Home Journals Articles Updates About
CN
image
收藏切换
Replacement of fish meal with cottonseed protein concentrate in Chinese mitten crab (Eriocheir sinensis): Nutrient digestibility, growth performance, free amino acid profile, and expression of genes related to nutrient metabolism
收藏切换
PDF
Xinting Liu, Danyang Zou, Yizhu Wang, Yutong Zhuang, Yang Liu, Yanyu Li, Zhenzhu Sun, Chaoxia Ye*
Animal Nutrition | 2024, 17(1) : 447 - 462
Less
收藏切换
Animal Nutrition | 2024, 17(1): 447-462
• Original Research Article •
Replacement of fish meal with cottonseed protein concentrate in Chinese mitten crab (Eriocheir sinensis): Nutrient digestibility, growth performance, free amino acid profile, and expression of genes related to nutrient metabolism
Full
Xinting Liu, Danyang Zou, Yizhu Wang, Yutong Zhuang, Yang Liu, Yanyu Li, Zhenzhu Sun, Chaoxia Ye*
Affiliations
  • Guangzhou Key Laboratory of Subtropical Biodiversity and Biomonitoring, Institute of Modern Aquaculture Science and Engineering, School of Life Science, South China Normal University, Guangzhou 510631, China
doi: 10.1016/j.aninu.2024.02.001
Outline
收藏切换

This study aimed to investigate the application of cottonseed protein concentrate (CPC) in Chinese mitten crabs (Eriocheir sinensis). First, the apparent digestibility coefficient (ADC) of CPC, fish meal and soybean meal were compared in crabs (21.72 ± 0.33 g). The protein ADC of CPC was 90.42%, which was significantly higher than that of soybean meal (83.16%) (P < 0.05). The ADC of Phe, Cys and Glu of CPC were significantly higher than those of fish meal, while the ADC of Ile, Leu, Lys, Met, Thr and Ala of CPC were significantly lower (P < 0.05). Second, we investigated the effects of fish meal substitution by CPC on growth performance, free amino acid profile, and expression of genes related to nutrient metabolism in crabs. Six diets were formulated by replacing 0%, 15%, 30%, 45%, 60% and 75% fish meal with CPC, namely FM, CPC15, CPC30, CPC45, CPC60, and CPC75. A total of 630 crabs (1.68 ± 0.00 g) were randomly divided into 18 tanks (3 tanks per group) and fed 3 times daily for 9 weeks. Results showed that CPC75 group significantly reduced growth performance, feed conversion efficiency, and free Ile, Leu, Lys, Met, and Thr contents in muscle (P < 0.05). The contents of free amino acids (Arg, His, Ile, Leu, Lys, Met, Phe, Thr, Val, Ala, Cys, Glu, Gly, Ser and Tyr) in hepatopancreas decreased linearly with the increase of dietary CPC level (P < 0.05). The substitution of more than 45% fish meal with CPC significantly decreased the concentration of delicious amino acids (Ala, Glu and Gly) in hepatopancreas (P < 0.05), which might adversely affect crab flavor. The expression of genes related to antioxidant capacity, protein transport, TOR pathway and lipid metabolism was significantly downregulated by increasing dietary CPC level (P < 0.05). In conclusion, based on the quadratic regression analysis of FCR and PER, the optimal replacement levels of fish meal with CPC in crab diet containing 35% fish meal were 32.36% and 35.38%, respectively. It is recommended that Ile, Leu and Thr be supplemented in addition to Met and Lys in the application of CPC.

Eriocheir sinensis  /  Cottonseed protein concentrate  /  Digestibility  /  Amino acid  /  TOR signaling pathway
Xinting Liu, Danyang Zou, Yizhu Wang, Yutong Zhuang, Yang Liu, Yanyu Li, Zhenzhu Sun, Chaoxia Ye. Replacement of fish meal with cottonseed protein concentrate in Chinese mitten crab (Eriocheir sinensis): Nutrient digestibility, growth performance, free amino acid profile, and expression of genes related to nutrient metabolism[J]. Animal Nutrition, 2024 , 17 (1) : 447 -462 . DOI: 10.1016/j.aninu.2024.02.001
Full Text
Less
1.　Introduction
Less
The Chinese mitten crab (Eriocheir sinensis) is an excellent protein source for human consumption with a unique flavor and high nutritional value. In 2019, the total production of Chinese mitten crabs reached roughly 800,000 tonnes (FAO, 2021), which is an economic pillar of freshwater aquaculture in China and hence the world. The application of formulated feeds in aquaculture has advanced in leaps and bounds to satisfy the nutritional requirements of aquatic animals and achieve scientific farming. It is well known that the quality of protein source significantly impacts the growth and health of farm animals. Among the many protein sources, fish meal has the characteristics of high digestibility, balanced amino acid composition, rich in vitamins, minerals and unsaturated fatty acids, and is considered to be the main source of protein in aquatic animal diets. However, in recent years, there has been a shortage of fish meal in the market due to the rapid growth of aquaculture and the stagnant annual worldwide fish meal production (Olsen and Hasan, 2012). It is therefore particularly important to find sustainable protein sources to replace fish meal.
Cottonseed is a plentiful plant protein that is sustainable in most regions of the world, and has a wide range of applications in food, agriculture and medicine industries (Kumar et al., 2021). A newly developed cottonseed product, cottonseed protein concentrate (CPC), has a high crude protein concentration and an excellent balance of amino acids (Xie et al., 2022). Compared with cottonseed meal, a large amount of free gossypol (an anti-nutritional factor unique to cottonseed) is removed from CPC by one-step low-temperature leaching and two-solvent stepwise extraction processes (Xie et al., 2022). Thus, CPC has great potential for application in feed.
Digestibility and utilization are generally important basic indicators of ingredient quality (Glencross, 2020). Evaluating the digestibility of nutrients in ingredients is one of the most effective ways to clarify the nutritional value of an ingredient for animals and its rational use (Glencross, 2020). However, the apparent digestibility coefficient (ADC) of CPC in crustaceans has not yet been determined. The utilization is obtained mainly by assessing feed intake (FI) and weight gain (WG) of the target species after feeding experimental diets to that species (Glencross, 2020). To date, CPC has been widely studied in fish, such as pearl gentian grouper (Epinephelus drummondhayi) (Chen et al., 2020; He et al., 2021; Ye et al., 2020; Yin et al., 2018), largemouth bass (Micropterus salmoides) (Huang et al., 2017; Xie et al., 2022; Xu et al., 2022), rainbow trout (Oncorhynchus mykiss) (Zhao et al., 2021) and golden pompano (Trachinotus ovatus) (Qin et al., 2021; Shen et al., 2020). In crustaceans, it has been shown that in a basal diet containing 25% fish meal, CPC could replace up to 45% of fish meal (CPC inclusion levels 0% to 13.16%) without having a negative impact on growth and disease resistance of Pacific white shrimp (Litopenaeus vannamei) (Wang et al., 2022). CPC could replace 19.07% and 22.73% of fish meal (CPC inclusion levels 8.90% to 10.61%) for swimming crab (Portunus trituberculatus) (Xie et al., 2022). Thus, CPC may not be used in high levels in crustacean diet formulations. One of the key reasons for limiting the dietary CPC level may be the contents and availability of amino acids (such as Met and Lys) in the feed after replacement. Therefore, it is particularly important to study the amino acid contents in the replacement diet, as well as the free amino acid levels in tissues and the regulated signaling pathways after animal feeding. However, research in this area is lacking, especially for crustaceans.
Besides serving as substrates for protein synthesis, amino acids are known as signaling molecules involved in cell growth and metabolic regulation (Skiba-Cassy et al., 2016). The target of rapamycin (TOR) is a highly conserved serine/threonine kinase that can be activated by amino acids to regulate cell growth and metabolism (Kim and Guan, 2011). TOR signaling pathway plays a crucial role in regulating protein synthesis in fish and mammals through eukaryotic translation initiation factor 4E (eIF4E), eIF4E binding protein (4EBP) and ribosomal protein S6 kinase (S6K) (Liu and Sabatini, 2020). Therefore, it is necessary to know whether replacement levels are associated with changes in amino acid composition and TOR signaling pathway. Clarifying the mechanisms of protein and amino acid metabolism in animals helps to achieve efficient feed utilization, and is vital for maintaining optimal growth of animals.
Meanwhile, it is shown that TOR signaling pathway can influence the expression of genes related to antioxidant regulation and lipid metabolism through downstream genes, thereby affecting antioxidant capacity and lipid levels (Jiang et al., 2016a, 2016b; Shay et al., 2012; Liu and Sabatini, 2020). In related studies, increased levels of substituting fish meal with a plant protein source significantly reduced antioxidant enzyme activities and body lipid levels in animals, which was detrimental to health and growth of the animals (Liu et al., 2020; Xie et al., 2022; Zhang et al., 2020). To the best of our knowledge, the effect of CPC substitution on gene expression of antioxidant regulation and lipid metabolism has not been explored. In particular, there is no report on the use of CPC in Chinese mitten crab diets in the literature. The purpose of present study was to evaluate the feasibility of CPC in crab diet in terms of compositional characteristics, digestibility and utilization. The effects of fish meal substitution by CPC on growth performance, feed utilization, free amino acid profile and expression of genes related to antioxidant regulation, protein intake and nutrient metabolism of crabs were also analyzed to provide information for the rational use of CPC in crab diet.
2.　Materials and methods
Less
2.1.　 Ethics statement
The South China Normal University's Animal Care and Use Committee approved this study and the relevant guidelines were strictly followed in the conduct of this study (approval reference number SCNU-SLS-2023-040).
2.2.　 Test ingredients
The three protein sources tested in this study were Peruvian fish meal, soybean meal (Yihai Kerry Arawana Holdings Co, Ltd.) and CPC (Xinjiang Jinlan Plant Protein Co., Ltd.). Nutrient composition of protein sources is provided in Table 1.
2.3.　 Digestibility trial – experimental design and diet preparation
The formulation of the experimental diets is listed in Table 2. The reference diet was formulated using fish meal, soybean meal, peanut meal and krill meal as the main protein sources, fish oil and soybean oil as the main lipid sources, and wheat flour as the main carbohydrate source. Each test ingredient was combined in a 3:7 (wt:wt) ratio with the reference diet. As an inner digestibility marker, yttrium oxide (Y2O3; Shanghai Macklin Biochemical Co., Ltd.), was added to the reference diet at 0.1%.
All ingredients were screened through a 100-mesh sieve, weighed, mixed thoroughly, added with distilled water, and then pelleted into 2.0-mm diameter size by a double screw extruder (F-26, South China University of Technology) and a granulator (G-250, South China University of Technology). The pellets were cooked in a blast drier (DKN812C, Chongqing Yamato Technology Co., Ltd.) at 90 °C for 1.5 h. After drying, the pellets were store at –20 °C until use.
2.4.　 Digestibility trial – crab rearing and experimental conditions
Feeding experiments were performed in an indoor recirculating aquaculture system at Biology Park of South China Normal University. The water temperature, dissolved oxygen and pH were 27.0 ± 1.5 °C, >6.0 mg/L and 7.7 to 8.3, respectively. Nitrite concentration was below 0.1 mg/L, and ammonia nitrogen concentration was below 0.2 mg/L.
Chinese mitten crabs were purchased from Chongming Breeding Base of Shanghai Ocean University and fed with commercial diet (Zhejiang Aohua Feed Co., LTD., crude protein content of 41%) for 2 weeks during acclimatization. At the beginning of experiment, 120 healthy crabs with an initial mean weight of 21.72 ± 0.33 g were selected and randomly divided into 12 fiberglass tanks (250 L, 3 tanks/diet, 10 crabs/tank). To reduce fighting, each tank was given 3 black arched tiles and 15 plastic pipes (5 pipes per bundle) as shelters. Crabs were fed twice daily at 07:30 and 16:30 during the culture experiment, and the residual diet and feces were collected 1.5 h after feeding. The culture experiment was conducted by collecting feces from the third week until sufficient fecal samples were available, lasting a total of 6 weeks.
2.5.　 Digestibility trial – feces sample collection and analysis
The fecal samples were gently rinsed with distilled water to remove debris. Daily collected feces were dried and stored at –20 °C for analysis of nutrients and yttrium.
2.6.　 Utilization trial – experimental design and diet preparation
The formulation and proximate composition of the experimental diets are listed in Table 3. Six isonitrogenous (44% crude protein) and isolipidic (8.5% crude lipid) diets were formulated using fish meal, soybean meal, rapeseed meal and krill meal as the main protein sources, fish oil and soybean oil as the main lipid sources, and wheat flour as the main carbohydrate source. The control group (FM) contained 35% fish meal, and five other diets (CPC15, CPC30, CPC45, CPC60 and CPC75 diets) were produced by replacing 15%, 30%, 45%, 60%, and 75% of fish meal with CPC, respectively. The final CPC inclusion levels were 0%, 5.90%, 11.70%, 17.60%, 23.50% and 29.40%, respectively. At each replacement level, Met and Lys were supplemented to maintain the consistency of the experimental diets. The amino acid composition of experimental diets is shown in Table 4. All ingredient handling and feed processing were as shown at Section 2.3, and the feed diameter was 1.0 mm.
2.7.　 Utilization trial – crab rearing and experimental conditions
Breeding equipment and conditions were shown in Section 2.4. Chinese mitten crabs were purchased from Chongming Breeding Base of Shanghai Ocean University and fed with commercial diet (Zhejiang Aohua Feed Co., Ltd., crude protein content of 41%) for 2 weeks during acclimatization. At the beginning of experiment, 630 healthy crabs with an initial mean weight of 1.68 ± 0.00 g were selected and distributed randomly into 18 fiberglass tanks (250 L, 3 tanks/diet, 35 crabs/tank). Five black arched tiles and 25 plastic pipes (5 pipes per bundle) were placed in each tank as a shelter to mitigate the fighting behavior. Crabs were fed 3 times daily at 07:30, 16:30 and 21:30 during the culture experiment, and the residual diet and feces were cleaned 1.5 h after feeding. The culture experiment lasted for 9 weeks.
2.8.　 Utilization trial – sample collection and analysis
At the end of the 9-week trial, crabs in each tank were counted and weighed to assess growth performance, feed utilization, and survival. Eight samples were randomly selected from each tank, and their hemolymph was extracted with 1.0 mL syringes, transferred into 1.5-mL Eppendorf (EP) tube, placed at 4 °C for 5 h and centrifuged at 1900 × g for 15 min. The upper serum was separated and frozen at –80 °C for subsequent biochemical index analysis. The hepatopancreas, intestine and muscle of each crab were then removed and quickly placed into pre-labeled and pre-cooled 1.5-mL EP tubes, which was frozen in liquid nitrogen and stored at –80 °C until further analysis of gene expression and amino acid composition. Six crabs were randomly chosen from each tank and put in a marked sealed bags and stored at –20 °C in order to assess whole-body proximate composition.
2.9.　 Digestibility calculation
ADC of dry matter, crude protein and amino acids of the reference diet and test diets were calculated using the formula as follows:
ADC of dry matter was calculated using dry matter instead of nutrient data.
ADC of the test ingredients were calculated based on the digestibility of the reference diet and experiment diets using the equation (Bureau and Hua, 2006):
where ADCi = apparent digestibility coefficient of dry matter or nutrient of the ingredients, ADCtd = apparent digestibility coefficient of the test diet, ADCrd = apparent digestibility coefficient of the reference diet, Ird = % of the reference diet in the mash, Ii = % of the test ingredient in the mash, Nrd = % of nutrient in the reference diet mash (as fed), and Ni = % of nutrient in the test ingredient (as fed).
2.10.　 Growth performance and feed utilization
The following variables were calculated:
2.11.　 Proximate composition analysis
Proximate composition of ingredients, experimental diets, and whole-body samples was analyzed in triplicate according to standard methods (AOAC, 2005). Moisture was determined by oven drying at 105 °C in a blast dryer (DKN812C, Chongqing Yamato Technology Co., Ltd.) to constant weight. Crude protein content was estimated using the Dumas nitrogen determination apparatus (Dumatherm DT NPRO, Gerhart Analytical Systems, Germany). Crude lipid was determined using the Soxhlet extraction with petroleum ether (boiling range 60 to 90 °C). Crude ash was analyzed after the sample was fully carbonized and placed in muffle furnace (FO610C, Yamato Scientific Co., Ltd., Tokyo, Japan) after burning at 550 °C for 6 h. The amino acid composition was measured by Guangzhou Chengyi Aquatic Technology Co., Ltd., according to GB/T 18246-2019 (China National Standard, 2019), using an oxidative hydrolysis method with an Automatic Amino Acid Analyzer (Biochrom 30+, Biochrom Ltd., Britain).
2.12.　 Serum biochemical indices analyses
Serum total protein (TP) was measured using the bicinchoninic acid (BCA) protein assay kit (P0011, Beyotime, Nantong, China) according to the manufacturer's instructions. Triglyceride (TG), total cholesterol (T-CHO), glucose concentrations, and alanine aminotransferase (ALT) and aspartate aminotransferase (AST) activities were measured using the commercial assay kits (A110-1, A111-1, F006-1, C009-2, C010-2; Nanjing Jiancheng Bioengineering Institute, Nanjing, China).
2.13.　 Hepatopancreas antioxidant enzymes activity assays
The hepatopancreas samples were precisely weighed and mixed with PBS buffer in accordance with the weight (g) to volume (mL) ratio of 1:9. Then it was homogenized in a refrigerated grinder and centrifuged at 13,700 × g for 15 min at 4 °C. An aliquot of the supernatant was taken for further analysis. The activities of superoxide dismutase (SOD) and total antioxidant capacity (T-AOC) were determined using the commercial assay kits (A001-3 and A015-2; Nanjing Jiancheng Bioengineering Institute, Nanjing, China).
2.14.　 Free amino acids determination
Approximately 100 mg of freeze-dried tissue sample was placed into 2.0-mL EP tube and 1.2 mL 10% sulfosalicylic acid was added, and the mixture was thoroughly shaken and centrifuged at 13,700 × g for 15 min at 4 °C. The supernatant was filtered by 0.22-μm membrane and transferred into 2.0-mL glass thread screw neck vials with 9-mm screw cap that contained a Red Silicone/Ivory PTFE (Thermo scientific, America). The composition and concentration of free amino acids in tissues were determined by High-speed Amino Acid Analyzer (L-8900, Hitachi High-Technologies Co., Tokyo, Japan).
2.15.　 Gene expression by quantitative real-time PCR (q-PCR)
The expression levels of genes related to antioxidant, protein metabolism and lipid metabolism were detected using q-PCR. Total RNA was isolated from the intestine and hepatopancreas with Trizol (9109, Takara, Japan). The purity of RNA was determined on a Nano Drop 2000 spectrophotometer (Thermo, USA). The following analysis only utilized RNA samples having the A260/A280 ratio between 1.8 and 2.0. And RNA integrity was verified using a 1.0% agarose gel. For each reverse transcription reaction, 1000 ng of RNA samples was treated with 5× gDNA digester Mix (Yeasen, Shanghai, China) to avoid genomic DNA amplification, and then reverse-transcribed into cDNA using 4× Hifair III SuperMix plus (Yeasen, Shanghai, China). The sequences of the primers are shown in Table 5.
Comparative gene mRNA quantification was employed. The q-PCR was conducted with an ABI 7500 Real-Time PCR System (Applied Biosystems, USA) in a 20 μL reaction mixture including 0.5 μL PCR forward primer (10 μm), 0.5 μL PCR reverse primer (10 μm), 2.0 μL cDNA solution, 10 μL SYBR Green Master Mix, and 7.0 μL dH2O. The reaction conditions were as follows: 95 °C for 5 min followed by 40 cycles consisting of 60 °C for 30 s and 95 °C for 15 s. The correlation coefficients (R2) of all standard curves were >0.98 and amplification efficiencies were between 90% and 110%. The expression levels of genes were calculated using 2−ΔΔCT method, and the normalization response was carried out with the ubiquitin/ribosomal S27 fusion protein (s27) gene as a reference.
2.16.　 Statistical analysis
Data are expressed as means and pooled SEM. One-way ANOVA was used to analyze the data. The differences with P-values < 0.05 were deemed significant in all analyses using the SPSS 25.0. Orthogonal polynomial contrasts were used in a subsequent trend analysis to assess if the significant effect was linear and/or quadratic. The correlations of amino acid changes in diet and tissues were estimated by Pearson's correlation.
3.　Results
Less
3.1.　 Nutritional composition of test ingredients
As shown in Table 1, the crude protein concentration of CPC was 65.95%, which was close to fish meal (69.62%) and substantially higher than soybean meal (53.52%). The crude lipid concentration of fish meal (11.01%) was higher, and that of soybean meal (1.41%) and CPC (0.68%) was lower. Compared to soybean meal (7.46%) and CPC (8.00%), fish meal had a higher crude ash concentration (17.06%). Among the amino acids, the contents of Ile (1.81%), Leu (3.65%), Lys (2.70%), Met (0.92%) and Thr (2.07%) of CPC were lower than those of fish meal (Ile 2.44%, Leu 4.91%, Lys 5.31%, Met 1.87%, Thr 2.92%). However, the contents of Arg (8.26%) and Phe (3.60%) of CPC were higher than those of fish meal (Arg 3.79%, Phe 2.71%). The essential amino acid (EAA, 27.65%) contents of CPC were lower than that of fish meal (EAA, 29.25%), and the total amino acid (TAA, 60.67%) content was close to that of fish meal (TAA, 60.94%).
3.2.　 Apparent digestibility of nutrients in test ingredients by E. sinensis
Table 6 shows the ADC of the dry matter, crude protein and amino acids of test ingredients. There was no discernible difference between the dry matter ADC of three protein sources, which varied from 70.68% to 73.50% for crabs (P > 0.05). The protein ADC of fish meal (87.21%) and CPC (90.42%) was significantly higher than that of soybean meal (83.16%) (P < 0.05).
Among the three protein sources, the ADC of Leu, Met, Thr and Ala of soybean meal and CPC were significantly lower than those of fish meal (P < 0.05). The ADC values of Ile and Lys in CPC were significantly lower, while Phe, Cys and Glu were significantly higher than those in fish meal and soybean meal (P < 0.05). The ADC of the remaining amino acids, EAA, and TAA were not significantly different among three protein sources (P > 0.05).
3.3.　 Growth performance and feed utilization
As shown in Table 7, when the basal diet contained 35% fish meal, of which 75% was replaced by CPC, crabs showed significantly lower final body weight, WG, SGR, PER and PR, and significantly higher FCR (P < 0.05). When CPC replaced 0% to 60% of fish meal, final body weight, WG, SGR, PER, PR and FCR of crabs were not significantly affected. The SR, FI, and HSI of crabs under various treatments did not differ significantly from one another (P > 0.05). Fish meal replacement with CPC had significant linear and quadratic impacts in FCR and PR, but only a quadratic effect in PER (P < 0.05). According to the quadratic regression analysis of FCR and PER with dietary CPC content, the optimal additions of CPC were 12.62% and 13.80%, respectively (Fig. 1), which corresponded to replacing 32.36% and 35.38% of the fish meal of the basal diet (containing 35% fish meal), respectively.
3.4.　 Proximate composition of whole crab
No significant effect of dietary CPC levels on the moisture, crude protein, lipid, and ash contents of whole crabs was observed (Table 8).
3.5.　 Biochemical indexes of serum
Table 9 shows the results of substituting fish meal by CPC on serum biochemical index of crabs. The concentration of T-CHO was linearly and quadratically affected by different dietary CPC levels (P < 0.05), while only quadratic effect was detected in the concentration of TG (P < 0.05). A significant positive linear trend existed between the activity of ALT and dietary CPC level (P < 0.05). Crabs fed the CPC15, CPC30, and CPC45 diets had higher serum TG concentrations than crabs fed other diets, and crabs fed the CPC30 and CPC45 diets had considerably higher serum T-CHO concentrations (P < 0.05). There were no discernible variations in the levels of TP, glucose, or AST activity across all treatments (P > 0.05).
3.6.　 Antioxidation capacity in hepatopancreas
As shown in Fig. 2, crabs fed the CPC75 diet had lower activity of SOD and lower level of gene expression of glutathione peroxidase (gpx) than those fed the other diets (P < 0.05). Copper-zinc superoxide dismutase (cu-zn sod), and cap 'n' collar isoform C (cncc) mRNA expression levels were significantly greater in CPC15 group crabs, whereas Kelch-like ECH-associated protein 1 (keap1) mRNA expression levels were significantly lower (P < 0.05). Fish meal substituted with CPC has no impact on the T-AOC value in the hepatopancreas (P > 0.05).
3.7.　 Free amino acid compositions of muscle and hepatopancreas
Free amino acids contents in muscle are shown in Table 10. The contents of Ile, Leu, Lys, Met, Thr and the total content of free EAA were the lowest in CPC75 group (P < 0.05). When compared to crabs fed other group diets, those fed the FM diet had muscles with a larger amount of Asp (P < 0.05). As the levels of CPC in diets increased, the content of Ala in crab muscles showed a tendency to increase after decrease, with higher levels in the CPC30, CPC45 and CPC60 groups (P < 0.05). The total amount of free non-essential amino acids (NEAA) and delicious amino acids (DAA) in muscle has no change when fish meal is substituted with CPC (P > 0.05).
Fish meal was substituted with CPC without affecting hepatopancreatic Asp and Pro (Table 11). Except Asp and Pro, other free amino acids of hepatopancreas were significantly affected by CPC and gradually decreased as the level of dietary CPC increased (P < 0.05). DAA also decreased as the level of dietary CPC increased (P < 0.05). The free amino acids concentrations of hepatopancreas and the level of CPC substituted fish meal linear variation were shown in Table 12. The findings showed that the free amino acids content, except for Arg, Asp and Pro, were negatively correlated with the CPC substitution level.
3.8.　 Correlation between changes in amino acid composition of the diet and tissues
The Pearson correlation coefficient between the dietary amino acid content and the tissue free amino acid content is shown in Fig. 3. Muscle Ile, Val and Gly levels were positively correlated with dietary Ile, Val and Gly contents, while His was negatively correlated (P < 0.05). In hepatopancreas, the concentrations of 13 free amino acids showed a significant linear correlation with the corresponding amino acid contents in the diet. Among them, the changes of Ile, Leu, Thr, Val, Ala, Gly and Pro were positively correlated, while that of Arg, His, Phe, Cys, Glu and Ser were negatively correlated (P < 0.05).
3.9.　 Expression levels of genes related to protein transport and TOR signaling pathway in the intestine
The expression of peptide transporter 1 (pept1), solute carrier family 7 member 5 (slc7a5), tor and s6k1 were negatively correlated with dietary CPC level, as shown in Fig. 4 (P < 0.05). Crabs in the CPC60 and CPC75 groups showed significantly higher levels of 4ebp mRNA expression (P < 0.05).
3.10.　 Expression levels of genes related to TOR signaling pathway and lipid metabolism in hepatopancreas
As shown in Fig. 5A, the expressions of tor, s6k1, regulatory-associated protein of TOR (raptor) and rheb were the highest in CPC15 group, but as CPC progressively replaced fish meal, the expression levels of tor and raptor significantly down-regulated (P < 0.05). The gene expression of eif4e and extracellular regulated protein kinases (erk) decreased significantly as the level of dietary CPC increased (P < 0.05).
The expression of sterol regulatory element-binding protein 1 (srebp1), Δ9 fatty acyl desaturase (Δ9 fad) and carnitine palmitoyltransferase 1 (cpt1) were the highest in CPC15 group, and significantly decreased as fish meal substitution by CPC increased (P < 0.05), as shown in Fig. 5B. In crabs fed diets supplemented with CPC, the expression level of carnitine acetyl-transferase (caat) was significantly downregulated.
4.　Discussion
Less
4.1.　 Nutritional composition of test ingredients
In the assessment process, ingredient characterization is an often overlooked but it is a crucial step for all nutritional studies (Glencross, 2020). Although the concentrations of some EAA (Ile, Leu, Lys, Met and Thr) of CPC were lower, Arg and Phe concentrations were higher than those of fish meal, and the protein level and TAA concentration were much higher than those of soybean meal and close to those of fish meal. This makes CPC a promising ingredient among the current dietary protein sources. Moreover, the lipid content of CPC was lower than that of fish meal and soybean meal, indicating that more fat needs to be supplemented when using CPC at high levels.
4.2.　 Apparent digestibility of nutrients in test ingredients by E. sinensis
The ADC of dry matter reflects the total level of digestion and absorption of nutrients by animals. A previous study found that the dry matter ADC of plant protein sources was lower than that of most animal protein sources due to their rich cellulose content (Mo et al., 2019), while the dry matter ADC of the tested ingredients in this study ranged from 70.68% to 73.50%, and there was no significant difference among the protein sources. This result indicates that the Chinese mitten crab, as an omnivorous animal, could make good use of the ingredients of legumes and cottonseeds.
Since the quality of dietary protein is an important factor affecting animal growth performance, protein and amino acid ADC is a practical and efficient way for evaluating ingredient. In this study, the protein ADC values of fish meal and soybean meal were 87.21% and 83.16%, respectively, which were generally consistent with those obtained in the study of Chinese mitten crab (Mu et al., 2000). The protein ADC of CPC was above 90%, which was not significantly different from that of fish meal. In a previous study, it was found that the protein ADC of cottonseed meal by the Chinese mitten crab tended to be close to soybean meal (Mu et al., 2000). Compared with the common cottonseed meal, the CPC has the characteristics of high protein and low gossypol through technical processing (Xie et al., 2022), which may be the reason why the protein ADC of CPC in this study was significantly higher than that of soybean meal, or even slightly higher than that of fish meal.
The composition and ADC of amino acids reflect the protein quality of the ingredients. Notably, the ADC values of Ile, Leu, Lys, Met, Thr and Ala of CPC were significantly lower than those of fish meal, suggesting that attention should be paid to the supplementation of these amino acids when using CPC at high levels. However, the ADC of EAA and TAA in CPC were not significantly different from those of fish meal. Therefore, CPC has the potential to replace fish meal as a protein source for crabs from the digestibility point of view, but this needs to be verified in culture experiments.
4.3.　 Growth performance and feed utilization
Although the protein content of CPC is close to that of fish meal, the Met and Lys contents are much lower than that of fish meal and cannot meet the requirements of crabs. Therefore, all the CPC diets were supplemented with crystal Met and Lys to achieve the same levels as the FM diet. After a 9-week feeding trial, based on the quadratic regression analysis of FCR and PER with dietary CPC content, the optimal replacement levels of fish meal with CPC in crab diets were estimated to be 32.36% and 35.38%, for FCR and PER, respectively. However, when the replacement level of fish meal with CPC was higher than 60%, it had significant adverse effects on growth performance and feed utilization. Additionally, it has been reported that replacement of 60% fish meal with CPC did not significantly affect WG of largemouth bass and hybrid grouper (Cui et al., 2022; Ye et al., 2020). According to previous studies, the addition of feed additives like Lys and Met can mitigate the negative effects of a high plant protein diet (Bulbul et al., 2015; Liu et al., 2014), and the reason why CPC substitution of 60% fish meal did not affect growth may be due to the supplement of Lys and Met in this study. However, the growth, FCR, PER and PR of the Chinese mitten crab were adversely affected when CPC replaced 75% of fish meal and the inclusion level reached 29.4%. Similar to this, when fish meal was replaced with CPC at 60% (CPC inclusion level 28%) in swimming crabs, both growth performance and feed utilization were negatively impacted (Xie et al., 2022). The results suggest that other factors besides Lys and Met may limit the high addition of CPC. On the one hand, excessive CPC may result in the diet not easy to digest and absorb. Plant is generally rich in fiber, which is not easily digested and absorbed by farm animals and can reduce the retention time of the diet in the intestine, which in turn leads to insufficient absorption of essential nutrients (Gonzalez-Pena et al., 2002; Hansen and Storebakken, 2007; Ren et al., 2020). On the other hand, an excess amount of CPC results in an imbalance of amino acids in the diet. The Arg concentration of CPC was much higher than that of fish meal, and it is possible that the excess Arg antagonized Lys, affecting its metabolism (Wang et al., 2021). In addition to Lys, Met and Arg, there are other amino acids significantly different in concentrations between fish meal and CPC, and the changes of dietary amino acids and tissue free amino acids caused by replacing fish meal with CPC remain to be explored.
4.4.　 Proximate composition in whole body of crabs
In the present study, there was no significant change in the whole body composition between the crabs fed diets supplemented with CPC and those with FM. Similar results were reported in Pacific white shrimps (Wan et al., 2018) and rainbow trouts (Zhao et al., 2021), which found that the level of dietary CPC replacing fish meal did not affect whole-body composition. Despite the fact that alternate protein sources did not have an impact on the composition of the whole-body (Sudaryono et al., 1995), high CPC levels reduced whole body crude lipid in studies of largemouth bass (Xu et al., 2022) and swimming crabs (Xie et al., 2022). In this study, it may be that the CPC level of 29.40% in the experimental feed did not reach a level that could significantly affect the whole-body composition of crabs, which is consistent with the results of the rainbow trout study (Zhao et al., 2021).
4.5.　 Biochemical indexes of serum
It is well known that serum and hepatopancreas components such as TP, TG, T-CHO and glucose are correlated with nutrient metabolism and immune response (Zhou et al., 2013). The results of the present study were consistent with those of a study on black carps, which showed that CPC had no significant effect on serum TP and glucose (Hu et al., 2015). However, our results showed that content of TG in CPC15, CPC30 and CPC45 groups and the content of T-CHO in CPC30 and CPC45 groups were significantly increased. On the whole, the TG and T-CHO contents of juvenile crabs first increased and then decreased with the increase of fish meal replacement by CPC, which is different from the previous study in which that T-CHO content in Pacific white shrimps decreased with increasing CPC levels (Wan et al., 2018). The intake and metabolism of lipids are key factors affecting changes in blood lipids, therefore it is necessary to study this aspect to explore the reasons for the increase in TG and T-CHO concentrations.
The ALT and AST are important enzymes in the hepatopancreas amino acid metabolism. The significant increase in the activities of these two enzymes in serum may indicate a damage of hepatopancreas function (Wang et al., 2014a). In present study, serum ALT activity significantly increased when dietary CPC replaced fish meal at levels above 45%, indicating that hepatopancreas function of the crab was impaired. Previous studies have also reported that excessive CPC in diet could harm cells and tissues (Wan et al., 2018; Xie et al., 2022).
4.6.　 Antioxidative capacity in hepatopancreas
Reactive oxygen species (ROS), which are frequently formed when substituting fish meal by plant protein sources, can cause oxidative damage that compromises the function of cells and tissues (Liu et al., 2020; Xie et al., 2022; Zhang et al., 2020). Important antioxidant system enzymes include SOD and GPx, of which Cu-Zn SOD is a class of SOD that is mostly present in eukaryotic cells' cytoplasm (Jiang et al., 2016b). When CPC replacement level reached 75% in this study, SOD activity and gpx expression were significantly lower than those in the control group. Additionally, as CPC level increased, cu-zn sod expression significantly downgraded. The expression of sod was significantly up-regulated after CPC replaced 15% fish meal in the study of white shrimp (Wang et al., 2022). In the swimming crab study, CPC substitution of 60% fish meal did not adversely affect expression of gpx, and moderate amounts of CPC increased SOD activity (Xie et al., 2022).
Unlike fish, CncC acts as an ortholog of nuclear factor erythroid 2-related factor 2 (Nrf2) in invertebrates, which could regulate antioxidant enzymes and corresponding genes to relieve oxidative stress (Jiang et al., 2016a; Wang et al., 2020). Keap1, the cytosolic repressor of CncC, blocks CncC nuclear transfer and expression (Bayliak et al., 2020; Li et al., 2019). When the amount of T-2 toxin was raised in the study of Chinese mitten crab, the expression of cncc first increased and then reduced, whereas the expression of keap1 exhibited the opposite trend (Wang et al., 2020). In the present study, we found that the expression of cu-zn sod, gpx, and cncc genes was significantly downregulated in the hepatopancreas of crabs in the CPC75 group. These findings suggest that high CPC may reduce the antioxidant capacity of crabs, due in part to its suppression of cncc expression levels. Further research is needed to determine the exact mechanism.
4.7.　 Free amino acid composition of muscle and hepatopancreas
In animals, all amino acids come from feed or body proteins. All NEAA produced by biosynthesis are transported to the free amino acid pool (Yao et al., 2022). The muscle system has the largest pool of free amino acids. Among the EAA, Ile, Leu, Lys, Met and Thr in muscle were significantly affected by the CPC level, all being the lowest in the CPC75 group. This suggests that attention should be paid to the supplementation of Ile, Leu and Thr in addition to the common limiting amino acids (Met and Lys) in CPC applications. Except for His, Ile, Val, and Gly, the variance of free amino acids in muscle did not exhibit a consistent trend with the composition of dietary amino acids, according to a correlation analysis. Similar to the CPC study of the largemouth bass (Xu et al., 2022) and Clostridium autoethanogenum protein study of white shrimps (Yao et al., 2022), the composition of muscle free amino acids may be reasonably stable and only marginally influenced by dietary amino acid composition and the digestibility of amino acids. The Ile, Leu, Thr, Val, Ala, Gly, and Pro in hepatopancreas had positive correlations with the relevant amino acids in the diet. Additionally, although the contents of dietary Arg, His, Phe, Cys, Glu, and Ser were on the increase, these amino acids in hepatopancreas decreased, resulting in a significant negative correlation between them. Overall, except Asp and Pro, hepatopancreas free amino acid contents had a negative linear relationship with the dietary CPC level, indicating that hepatopancreas free amino acid contents were more sensitive to replacement level than muscle free amino acid contents.
In addition to growth performance, the meat quality of animals is also a major concern for consumers. Among the free amino acids, DAA are important factors affecting flavor, among which Ala and Gly present sweetness and Glu and Asp present freshness (Chen and Zhang, 2007; Wang et al., 2016). In previous fish meal substitution studies, the reduction of fish meal usually reduced the DAA contents and had an adverse effect on flavor. The concentrations of free Glu, Asp, and Gly in muscle were dramatically reduced in diets for Pacific white shrimps when more than 45% of the fish meal were substituted by C. autoethanogenum protein (Yao et al., 2022). Replacing fish meal completely with soy protein concentrate significantly reduced the contents of DAA in grass carp (Ctenopharygodon idella) muscle (Yang et al., 2021). In the diets of large yellow croakers (Larimichthys crocea), substituting 30% fish meal with Antarctic krill meal significantly reduced the content of Glu, Gly and Ala (Wei et al., 2019). In a CPC study on largemouth bass, Glu and Ala content in muscle increased but DAA contents did not differ significantly (Xu et al., 2022). In the present study, although a moderate amount CPC addition increased Ala content and decreased Asp content, the total DAA content in muscle did not differ considerably from that of the FM group. Unlike fish and shrimp, the hepatopancreas of crabs is also an edible part. In hepatopancreas, when CPC replaced 45% or more fish meal, the contents of Ala, Glu, Gly and total DAA amount were significantly decreased, which may significantly reduce umami and sweet taste. Therefore, CPC substitution of fish meal above 45% can have a negative impact on the flavor of crabs.
4.8.　 Genes associated with protein transport and TOR signaling pathway in the intestine
The intestine is an important site for digestion, absorption and nutrient exchange of crustaceans, and it is also one of the most closely related parts between organism and the external environment. PEPT1 transported large amounts of amino acids in dipeptides/tripeptides form (Terova et al., 2009; Xu et al., 2020; Zhou et al., 2022). Small peptides are more efficiently absorbed than free amino acids, so PEPT1 has great potential to optimize absorption (Wang et al., 2017). SLC7A5 is a sodium independent high-affinity amino acid transporter, and together with solute carrier family 3 member 2 (SLC3A2) mediates cellular uptake of the large neutral amino acids such as Phe, Tyr, Leu and Trp (Wang et al., 2018). Studies have shown that the TOR signaling pathway can regulate the expression of amino acid and peptide transporters in the intestine of Caenorhabditis elegans (Benner et al., 2011) and grass carp (Wang et al., 2018), respectively. The present results show that increasing the dietary CPC level could inhibit intestinal TOR signaling pathway (down-regulating tor and s6k1 expression and up-regulating 4ebp expression) and the expressions of pept1 and scl7a5. In the grass carp study, the linear down-regulation of pept1 and partial amino acid transporter gene expression in various intestinal segments was a significant factor for the decrease of intestinal free amino acids with the increase of dietary gossypol level (Wang et al., 2018). Therefore, in the present study, with the increase of CPC level, the lack of some free amino acids in hepatopancreas and muscle could be attributed to the reduced expression levels of pept1 and slc7a5, resulting in insufficient uptake of amino acids.
4.9.　 Genes associated with nutrition metabolism in hepatopancreas
In crustaceans, the hepatopancreas not only absorb and store nutrients, but also serve as the metabolic center of the body (Wang et al., 2014b; Zhang et al., 2022). The TOR is a serine/threonine protein kinase member of the phosphoinositide-3-kinase-related kinase family, and is involved in the regulation of several key metabolic mechanisms (Kim and Guan, 2011). TOR signaling pathway, including mTOR complex 1 (mTORC1) and mTORC2, is a major nutrient sensitive pathway that plays an important role in substance metabolism and cell growth. The two complexes differ in function and structure, with the former sensitive to rapamycin and nutrients, while the latter insensitive (Jewell et al., 2013; Magnuson et al., 2012). In this study, the expression levels of tor, s6k1, raptor and rheb involved in the TOR signaling pathway were up-regulated first and then down-regulated with the addition of CPC in diets. The results show that appropriate CPC in the diet could activate TOR pathway, which is consistent with the study in swimming crabs (Xie et al., 2022). The dietary content of Arg increased with the increase of CPC level, and studies have shown that an appropriate level of Arg can activate TOR signaling pathway (Chantranupong et al., 2016; Liu et al., 2021; Wang et al., 2021). Therefore, we speculate that the Arg content in the CPC15 diet is beneficial to increase the expression of key genes in the TOR signaling pathway and promote protein synthesis. The reason for the inhibition of TOR signaling pathway with increasing CPC replacement levels may be that the excessive Arg content in diet has an antagonistic effect on Lys, which affects Lys utilization and metabolism. Furthermore, inadequacy of most free amino acids in hepatopancreas may also be an important reason. Therefore, the TOR signaling pathway was downregulated when CPC replaced 75% fish meal, which may have led to reduced growth of crab.
In addition, the nuclear translocation and processing of the SREBPs can be regulated by TOR through S6K1, thereby affecting lipid synthesis (Liu and Sabatini, 2020). SREBP1 and Δ9 FAD were crucial transcription factors for lipogenesis related genes and played a central role in cellular adipogenesis and lipid homeostasis (Arrese and Soulages, 2010; Hishikawa et al., 2020; Wu et al., 2014). In this study, the expression trends of tor and s6k1 were similar to those of srebp1 and Δ9 fad, so the expression changes of lipid metabolism-related genes may be affected by the expression of TOR signaling pathway related genes. Cpt1 and Caat are key enzymes of fatty acid oxidation and catalyze the conversion of fatty acid coenzyme into fatty acid carnitine (Coleman, 2004). In the study of golden pompano, when 60% fish meal was replaced by low-phenolic cotton seed meal (CSM), the expression of lipid anabolism genes was downregulated and the expression of lipid catabolism genes was activated, which may be the reason for the decreased crude lipid and partial fatty acids contents of whole fish (Qin et al., 2021). In the study of Nile tilapia (Oreochromis niloticus), high CPC substitution levels downregulated fatty acid synthesis gene expression, up-regulated catabolic gene expression and reduced lipid accumulation in the liver (Wu et al., 2022). However, in this study, high levels of CPC downregulated the expression of lipid anabolism and catabolism genes, which might be attributed to self-regulation to maintain body lipid balance in crabs. These results may provide a reasonable explanation for the absence of changes in crude lipid of whole-crab after replacement of fish meal with CPC.
5.　Conclusions
Less
In conclusion, the apparent protein digestibility of CPC is relatively high, which is close to that of fish meal. CPC can be used as a high-quality protein source in the diets of Chinese mitten crabs. Based on the quadratic regression analysis of FCR and PER with the dietary CPC content, the optimal replacement levels of CPC for fish meal were estimated to be 32.36% and 35.38% for FCR and PER, respectively. When the replacement level of fish meal with CPC exceeded 45%, the antioxidant capacity and free amino acids contents in hepatopancreas were significantly reduced. Meanwhile, in the application of CPC, attention should be paid to the supplementation of Ile, Leu and Thr in addition to common limiting amino acids (Met and Lys). Because CPC affects the hepatopancreas free amino acid contents and may affect flavor of crabs, it is not recommended to add CPC to pre-market crab diet.
References
Less
AOAC. Official Methods of Analysis. 18th ed. Gaithersburg, MD: AOAC International; 2005.
Arrese EL, Soulages JL. Insect fat body: energy, metabolism, and regulation. Annu Rev Entomol 2010;55:207-25.
Bayliak MM, Demianchuk OI, Gospodaryov DV, Abrat OB, Lylyk MP, Storey KB, Lushchak VI. Mutations in genes cnc or dKeap1 modulate stress resistance and metabolic processes in Drosophila melanogaster. Comp Biochem Physiol A Mol Integr Physiol 2020;248:110746.
Benner J, Daniel H, Spanier B, Hansen IA. A glutathione peroxidase, intracellular peptidases and the TOR complexes regulate peptide transporter PEPT-1 in C. elegans. PLoS One 2011;6:e25624.
Bulbul M, Kader MA, Ambak MA, Hossain MS, Ishikawa M, Koshio S. Effects of crystalline amino acids, phytase and fish soluble supplements in improving nutritive values of high plant protein based diets for kuruma shrimp, Marsupenaeus japonicus. Aquaculture 2015;438:98-104.
Bureau DP, Hua K. Letter to the Editor of Aquaculture. Aquaculture 2006;252:103-5.
Chantranupong L, Scaria SM, Saxton RA, Gygi MP, Shen K, Wyant GA, Wang T, Harper JW, Gygi SP, Sabatini DM. The CASTOR proteins are arginine sensors for the mTORC1 pathway. Cell 2016;165:153-64.
Chen D, Zhang M. Non-volatile taste active compounds in the meat of Chinese mitten crab (Eriocheir sinensis). Food Chem 2007;104:1200-5.
Chen G, Yin B, Liu H, Tan B, Dong X, Yang Q, Chi S, Zhang S. Effects of fishmeal replacement with cottonseed protein concentrate on growth, digestive proteinase, intestinal morphology and microflora in pearl gentian grouper (♀Epinephelus fuscoguttatus × ♂Epinephelus lanceolatu). Aquac Res 2020;51:2870-84.
China National Standard. Determination of amino acids in feeds. GB/T 18246-2019. Beijing: Standards Press of China; 2019.
Coleman R. Enzymes of triacylglycerol synthesis and their regulation. Prog Lipid Res 2004;43:134-76.
Cui Z, Zhang J, Ren X, Wang Y. Replacing dietary fish meal improves ecosystem services of largemouth bass (Micropterus salmoides) farming. Aquaculture 2022;550:737830.
FAO. Fishery and Aquaculture Statistics 2019. Rome: Food and Agriculture Organization of the United Nations; 2021.
Glencross BD. A feed is still only as good as its ingredients: an update on the nutritional research strategies for the optimal evaluation of ingredients for aquaculture feeds. Aquacult Nutr 2020;26:1871-83.
Gonzalez-Pena MDC, Anderson AJ, Smith DM, Moreira GS. Effect of dietary cellulose on digestion in the prawn Macrobrachium rosenbergii. Aquaculture 2002;211:291-303.
Hansen JØ, Storebakken T. Effects of dietary cellulose level on pellet quality and nutrient digestibilities in rainbow trout (Oncorhynchus mykiss). Aquaculture 2007;272:458-65.
He Y, Guo X, Tan B, Dong X, Yang Q, Liu H, Zhang S, Chi S. Replacing fishmeal with cottonseed protein concentrate in feed for pearl gentian groupers (Epinephelus fuscoguttatus♀ × E. lanceolatus♂): effects on growth and expressions of key genes involved in appetite and hepatic glucose and lipid metabolism. Aquacult Rep 2021;20:100710.
Hishikawa D, Yanagida K, Nagata K, Kanatani A, Iizuka Y, Hamano F, Yasuda M, Okamura T, Shindou H, Shimizu T. Hepatic levels of DHA-containing phospholipids instruct SREBP1-mediated synthesis and systemic delivery of polyunsaturated fatty acids. iScience 2020;23:101495.
Hu Y, Huang Y, Feng F, Zhong L, Ai Q, Xiao T, Wen H. Effect of soybean meal replacement by cottonseed meal on growth, feed utilization and some blood physiological/biochemical indices of juvenile black carp, Mylopharyngodon piceus. Aquac Res 2015;46:2490-500.
Huang D, Wu Y, Lin Y, Chen J, Karrow N, Ren X, Wang Y. Dietary protein and lipid requirements for juvenile largemouth bass, Micropterus salmoides. J World Aquacult Soc 2017;48:782-90.
Jewell JL, Russel RC, Guan K. Amino acid signalling upstream of mTOR. Nat Rev Mol Cell Biol 2013;14:133-9.
Jiang W, Wu P, Tang R, Liu Y, Kuang S, Jiang J, Tang L, Tang W, Zhang Y, Zhou X, Feng L. Nutritive values, flavor amino acids, healthcare fatty acids and flesh quality improved by manganese referring to up-regulating the antioxidant capacity and signaling molecules TOR and Nrf2 in the muscle of fish. Food Res Int 2016a;89:670-8.
Jiang WD, Wena HL, Liu Y, Jiang J, Wu P, Zhao J, Kuang SY, Tang L, Tang WN, Zhang YA. Enhanced muscle nutrient content and flesh quality, resulting from tryptophan, is associated with anti-oxidative damage referred to the Nrf2 and TOR signalling factors in young grass carp (Ctenopharyngodon idella): avoid tryptophan deficiency or excess. Food Chem 2016b;199:210-9.
Kim J, Guan K. Amino acid signaling in TOR activation. Annu Rev Biochem 2011;80:1001-32.
Kumar M, Tomar M, Punia S, Grasso S, Arrutia F, Choudhary J, Surinder SG, Pooja VH, Archana MI, Sharmila PJ, KR, Sangram DL, Potkule J, Sujata SA, Ryszard AM. Cottonseed: a sustainable contributor to global protein requirements. Trends Food Sci Technol 2021:100-13.
Li J, Mao T, Wang H, Lu Z, Qu J, Fang Y, Chen J, Li M, Cheng X, Hu J, Gu Z, Ni M, Li F, Li B. The CncC/keap1 pathway is activated in high temperature-induced metamorphosis and mediates the expression of Cyp450 genes in silkworm, Bombyx mori. Biochem Biophys Res Commun 2019;514:1045-50.
Liu GY, Sabatini DM. mTOR at the nexus of nutrition, growth, ageing and disease. Nat Rev Mol Cell Biol 2020;21:183-203.
Liu X, Han B, Xu J, Zhu J, Hu J, Wan W, Miao S. Replacement of fishmeal with soybean meal affects the growth performance, digestive enzymes, intestinal microbiota and immunity of Carassius auratus gibelio♀ × Cyprinus carpio♂. Aquacult Rep 2020;18:100472.
Liu Y, He G, Wang Q, Mai K, Xu W, Zhou H. Hydroxyproline supplementation on the performances of high plant protein source based diets in turbot (Scophthalmus maximus L.). Aquaculture 2014;433:476-80.
Liu Y, Yu H, Guo Y, Huang D, Liu J, Pan M, Wang L, Zhang W, Mai K. Arginine regulates TOR signaling pathway through SLC38A9 in Abalone Haliotis discus hannai. Cells-Basel 2021;10:2552.
Magnuson B, Ekim B, Fingar DC. Regulation and function of ribosomal protein S6 kinase (S6K) within mTOR signalling networks. Biochem J 2012;441:1-21.
Mo AJ, Sun JX, Wang YH, Yang K, Yang HS, Yuan YC. Apparent digestibility of protein, energy and amino acids in nine protein sources at two content levels for Mandarin fish, Siniperca chuatsi. Aquaculture 2019:42-50.
Mu YY, Lam TJ, Guo JY, Shim KF. Protein digestibility and amino acid availability of several protein sources for juvenile Chinese hairy crab Eriocheir sinensis H. Milne-Edwards (Decapoda,Grapsidae). Aquac Res 2000;31:757-65.
Olsen RL, Hasan MR. A limited supply of fishmeal: impact on future increases in global aquaculture production. Trends Food Sci Technol 2012;27:120-8.
Qin Y, He C, Wang W, Yang P, Wang J, Qin Q, et al. Changes in growth performance, nutrient metabolism, antioxidant defense and immune response after fishmeal was replaced by low-gossypol cottonseed meal in golden pompano (Trachinotus ovatus). Front Mar Sci 2021;8:775575.
Ren S, Cai C, Cui G, Ni Q, Jiang R, Su X, Wang Q, Chen W, Zhang J, Wu P, Lu J, Ye Y. High dosages of pectin and cellulose cause different degrees of damage to the livers and intestines of Pelteobagrus fulvidraco. Aquaculture 2020;514:734445.
Shay KP, Michels AJ, Li W, Kong ANT, Hagen TM. Cap-independent Nrf2 translation is part of a lipoic acid-stimulated detoxification stress response. Biochim Biophys Acta 2012;1823:1102-9.
Shen J, Liu H, Tan B, Dong X, Yang Q, Chi S, Zhang S. Effects of replacement of fishmeal with cottonseed protein concentrate on the growth, intestinal microflora, haematological and antioxidant indices of juvenile golden pompano (Trachinotus ovatus). Aquacult Nutr 2020;26:1119-30.
Skiba-Cassy S, Geurden I, Panserat S, Seiliez I. Dietary methionine imbalance alters the transcriptional regulation of genes involved in glucose, lipid and amino acid metabolism in the liver of rainbow trout (Oncorhynchus mykiss). Aquaculture 2016;454:56-65.
Sudaryono A, Hoxey MJ, Kailis SG, Evans LH. Investigation of alternative protein sources in practical diets for juvenile shrimp, Penaeus monodon. Aquaculture 1995;134:313-23.
Terova G, Corà S, Verri T, Rimoldi S, Bernardini G, Saroglia M. Impact of feed availability on PepT1 mRNA expression levels in sea bass (Dicentrarchus labrax). Aquaculture 2009;294:288-99.
Wan M, Yin P, Fang W, Xie S, Chen SJ, Tian LX, Niu J. The effect of replacement of fishmeal by concentrated dephenolization cottonseed protein on the growth, body composition, haemolymph indexes and haematological enzyme activities of the Pacific white shrimp (Litopenaeus vannamei). Aquacult Nutr 2018;24:1845-54.
Wang C, Wang X, Huang Y, Bu X, Xiao S, Qin C, Qiao F, Qin JG, Chen L. Effects of dietary T-2 toxin on gut health and gut microbiota composition of the juvenile Chinese mitten crab (Eriocheir sinensis). Fish Shellfish Immunol 2020;106:574-82.
Wang H, Hu X, Zheng Y, Chen J, Tan B, Shi L, Zhang S. Effects of replacing fish meal with cottonseed protein concentrate on the growth, immune responses, digestive ability and intestinal microbial flora in Litopenaeus vannamei. Fish Shellfish Immunol 2022;128:91-100.
Wang J, Yan X, Lu R, Meng X, Nie G. Peptide transporter 1 (PepT1) in fish: a review. Aquac Fish 2017;2:193-206.
Wang K, Jiang W, Wu P, Liu Y, Jiang J, Kuang S, Tang L, Zhang Y, Zhou X, Feng L. Gossypol reduced the intestinal amino acid absorption capacity of young grass carp (Ctenopharyngodon idella). Aquaculture 2018;492:46-58.
Wang Q, Xu Z, Ai Q. Arginine metabolism and its functions in growth, nutrient utilization, and immunonutrition of fish. Anim Nutr 2021;7:716-27.
Wang S, He Y, Wang Y, Tao N, Wu X, Wang X, Qiu W, Ma M. Comparison of flavour qualities of three sourced Eriocheir sinensis. Food Chem 2016;200:24-31.
Wang W, Wu X, Liu Z, Zheng H, Cheng Y. Insights into hepatopancreatic functions for nutrition metabolism and ovarian development in the crab Portunus trituberculatus: gene discovery in the comparative transcriptome of different hepatopancreas stages. PLoS One 2014a;9:e84921.
Wang X, Li X, Leng X, Shan L, Zhao J, Wang Y. Effects of dietary cottonseed meal level on the growth, hematological indices, liver and gonad histology of juvenile common carp (Cyprinus carpio). Aquaculture 2014b;428-429:79-87.
Wei Y, Shen H, Xu W, Pan Y, Chen J, Zhang W, Mai K. Replacement of dietary fishmeal by Antarctic krill meal on growth performance, intestinal morphology, body composition and organoleptic quality of large yellow croaker Larimichthys crocea. Aquaculture 2019;512:734281.
Wu H, Li W, Zhang L, Zhou N, Ye Z, Wang X, Zhang W, Qiao F, Du Z, Zhang M. Microbiota derived butyrate affected the muscle texture of Nile tilapia (Oreochromis niloticus) fed with different protein sources. Food Chem 2022;393:133392.
Wu Z, Soulages JL, Joshi BD, Daniel SM, Hager ZJ, Arrese EL. TGL-mediated lipolysis in Manduca sexta fat body: possible roles for lipoamide-dehydrogenase (LipDH) and high-density lipophorin (HDLp). Insect Biochem Mol Biol 2014;45:58-68.
Xie S, Zhou Q, Zhang X, Zhu T, Guo C, Yang Z, Luo J, Yuan Y, Hu X, Jiao L, Jin M. Effect of dietary replacement of fish meal with low-gossypol cottonseed protein concentrate on growth performance and expressions of genes related to protein metabolism for swimming crab (Portunus trituberculatus). Aquaculture 2022;549:737820.
Xu C, Liu W, Zhang D, Liu J, Zheng X, Zhang C, Yao J, Zhu C, Chi C. Effects of partial fish meal replacement with two fermented soybean meals on the growth of and protein metabolism in the Chinese mitten crab (Eriocheir sinensis). Aquacult Rep 2020:100328.
Xu X, Yang H, Zhang C, Bian Y, Yao W, Xu Z, Wang Y, Li X, Leng X. Effects of replacing fishmeal with cottonseed protein concentrate on growth performance, flesh quality and gossypol deposition of largemouth bass (Micropterus salmoides). Aquaculture 2022;548:737551.
Yang L, Wu P, Feng L, Jiang W, Liu Y, Kuang S, Tang L, Zhou X. Guanidinoacetic acid supplementation totally based on vegetable meal diet improved the growth performance, muscle flavor components and sensory characteristics of on-growing grass carp (Ctenopharygodon idella). Aquaculture 2021;531:735841.
Yao W, Yang P, Zhang X, Xu X, Zhang C, Li X, Leng X. Effects of replacing dietary fish meal with Clostridium autoethanogenum protein on growth and flesh quality of Pacific white shrimp (Litopenaeus vannamei). Aquaculture 2022;549:737770.
Ye G, Dong X, Yang Q, Chi S, Liu H, Zhang H, Tan B, Zhang S. Low-gossypol cottonseed protein concentrate used as a replacement of fish meal for juvenile hybrid grouper (Epinephelus fuscoguttatus♀ × Epinephelus lanceolatus♂): effects on growth performance, immune responses and intestinal microbiota. Aquaculture 2020;524:735309.
Yin B, Liu H, Tan B, Dong X, Chi S, Yang Q, Zhang S, Chen L. Cottonseed protein concentrate (CPC) suppresses immune function in different intestinal segments of hybrid grouper ♀Epinephelus fuscoguttatus × ♂Epinephelus lanceolatu via TLR-2/MyD88 signaling pathways. Fish Shellfish Immunol 2018;81:318-28.
Zhang L, Tao N, Wu X, Wang X. Metabolomics of the hepatopancreas in Chinese mitten crabs (Eriocheir sinensis). Food Res Int 2022;152:110914.
Zhang X, Wang H, Zhang J, Lin B, Chen L, Wang Q, Li G, Deng J. Assessment of rapeseed meal as fish meal alternative in diets for juvenile Asian red-tailed catfish (Hemibagrus wyckioides). Aquacult Rep 2020;18:100497.
Zhao W, Liu Z, Niu J. Growth performance, intestinal histomorphology, body composition, hematological and antioxidant parameters of Oncorhynchus mykiss were not detrimentally affected by replacement of fish meal with concentrated dephenolization cottonseed protein. Aquacult Rep 2021;19:100557.
Zhou F, Ding X, Feng H, Xu Y, Xue H, Zhang J, Ng W. The dietary protein requirement of a new Japanese strain of juvenile Chinese soft shell turtle, Pelodiscus sinensis. Aquaculture 2013;412-413:74-80.
Zhou Y, Guo M, Li Y, Zhang Y, Xu W, Zhao D, Chen Y, Zuo A, Qu F, Tang J, Cao S, Liu Z. Effects of Ghrelin on intestinal cell proliferation, the expression of protein absorption and metabolism factors in juvenile grass carp (Ctenopharyngodon idella). Aquacult Rep 2022;22:100928.
Appendix
Less
Year 2024 volume 17 Issue 1
PDF
67
42
Cite this Article
BibTeX
Article Info
doi: 10.1016/j.aninu.2024.02.001
  • Receive Date：2023-07-03
  • Online Date：2026-01-28
Article Data
Affiliations
History
  • Received：2023-07-03
  • Revised：2024-01-31
  • Accepted：2024-02-10
Affiliations
    Guangzhou Key Laboratory of Subtropical Biodiversity and Biomonitoring, Institute of Modern Aquaculture Science and Engineering, School of Life Science, South China Normal University, Guangzhou 510631, China

Corresponding:

*

Corresponding author. E-mail address: (C. Ye).
References
Share
https://castjournals.cast.org.cn/joweb/aninu/EN/10.1016/j.aninu.2024.02.001
Share to
QR

Scan QR to access full text

Cite this article
BibTeX
Citations
表12种不同金属材料的力学参数
科
Family		 属数
Number of
genus		 种数
Number of
species		 占总种数比例
Percentage of
total species (%)		 属
Genus		 种数
Number of
species		 占总种数比例
Percentage of total
species (%)
鹅膏菌科Amanitaceae 2 11 5.26 鹅膏菌属 Amanita 10 4.78
小菇科 Mycenaceae 2 12 5.74 丝盖伞属 Inocybe 5 2.39
多孔菌科 Polyporaceae 8 14 6.70 蜡蘑属 Laccaria 5 2.39
红菇科 Russulaceae 3 23 11.00 小皮伞属 Marasmius 6 2.87
小菇属 Mycena 11 5.26
光柄菇属 Pluteus 5 2.39
红菇属 Russula 17 8.13
栓菌属 Trametes 5 2.39
关闭全屏
  • BibTeX
  • EndNote
  • RefWorks
  • TxT
Links
Articles
Latest Articles
Most Read
Collections
Updates
Events
News
Multimedia
About
About Us
Contact
No. 86 Xueyuan South Road, Haidian District, Beijing
100081
010-62199257
qkjq@cast.org.cn

Copyright © 2025 China Association for Science and Technology. All rights reserved. For all open access content, the relevant licensing terms apply.
Sponsored by the Office of the Leading Group for Cybersecurity and Informatization of CAST, and supported by Science and Technology Review Publishing House