Standardized ileal digestibility coefficients (SIDC) of nitrogen (N) and amino acids (AA) in two protein sources (soybean meal [SBM] and canola meal [CM]) were investigated at six broiler ages (d 7, 14, 21, 28, 35, and 42). Two assay diets were formulated to contain either SBM (413 g/kg) or CM (553 g/kg) as the sole dietary AA source. Titanium dioxide (5 g/kg) was added as an indigestible marker. A total of 696 male broilers at 1 d old were allotted to 12 replicate cages per age group. Each assay diet was offered to birds for 4 d prior to the ileal digesta collection on d 7 (14 birds/cage), 14 (12 birds/cage), 21 (10 birds/cage), 28 (8 birds/cage), 35 (8 birds/cage) and 42 (6 birds/cage), respectively. The apparent digestibility coefficients were standardized using age-specific basal endogenous AA flows. In the SBM group, though the SIDC of N tended to be influenced (quadratic; P = 0.075) by age, no linear or quadratic response of age effect was observed on the average SIDC of indispensable (IAA) and total AA (TAA). An age effect (quadratic; P < 0.05) was observed on the average SIDC of dispensable AA (DAA) in SBM with the highest value recorded at d 7, followed by a decrease from d 14 to 28, which increased beyond d 35. The SIDC of some individual AA (Arg, Thr, Trp, Cys, Pro) were affected (P < 0.05 or P < 0.001) in a quadratic manner by age. In the CM, the SIDC of N, average SIDC of IAA, DAA and TAA were influenced (quadratic; P < 0.05 or P < 0.001) by age. The SIDC of N and average SIDC of DAA and TAA were higher from d 7 to 14, declined at d 21, and then increased beyond d 28. The average SIDC of IAA was low between d 7 and 28 and increased thereafter. The SIDC of individual AA were affected (linear or quadratic; P < 0.05 or P < 0.001) by different magnitudes by age. The age influence on the SIDC AA was variable, depending on the protein source and AA. The results demonstrate that age-specific SIDC AA data might need consideration in broiler feed formulations.

This study aimed to determine the regulatory mechanism of dietary zinc lactate (ZL) supplementation on intestinal oxidative stress damage in a paraquat (PQ)-induced piglet model. Twenty-eight piglets (mean body weight 9.51 ± 0.23 kg) weaned at 28 d of age were randomly divided into control, ZL, PQ, and ZL + PQ groups (n = 7 in each group). The ZL-supplemented diet had little effect on growth performance under normal physiological conditions. However, under PQ challenge, ZL supplementation significantly improved average daily gain (P < 0.05) and reduced the frequency of diarrhea. ZL improved intestinal morphology and ultrastructure by significantly increasing the expression level of the jejunal tight junction protein, zonula occludens-1 (ZO-1) (P < 0.05), and intestinal zinc transport and absorption in PQ-induced piglets, which reduced intestinal permeability. ZL supplementation also enhanced the expression of antioxidant and anti-inflammatory factor-related genes and decreased inflammatory cytokine expression and secretion in PQ-induced piglets. Furthermore, ZL treatment significantly inhibited the activation of constitutive androstane receptor (CAR) signaling (P < 0.01) in PQ-induced piglets and altered the structure of the gut microbiota, especially by significantly increasing the abundance of beneficial gut microbes, including UCG_002, Ruminococcus, Rikenellaceae_RC9_gut_group, Christensenellaceae_R_7_group, Treponema, unclassified_Christensenellaceae, and unclassified_Erysipelotrichaceae (P < 0.05). These data reveal that pre-administration of ZL to piglets can suppress intestinal oxidative stress by improving antioxidant and anti-inflammatory capacity and regulating the crosstalk between CAR signaling and gut microbiota.

Skatole, a strong fecal odor substance, is generated through microbial degradation of tryptophan in the animal hindgut. It easily accumulates in adipose tissue and affects meat quality. In this study, the effect of mulberry leaf supplementation on skatole in finishing pigs was studied. In a 35-day trial, 20 finishing pigs (barrows and gilts) were fed with a basal diet or basal diet with 6% mulberry leaves. Growth performance of the pigs (n = 10) was automatically recorded by a performance-testing feeder system and 8 pigs in each treatment were slaughtered and sampled for the remaining tests. Skatole and short-chain fatty acids were detected using HPLC and gas chromatography, respectively. Fecal microbiota were analyzed using 16S rRNA gene sequencing. The metabolomics analysis of feces and serum was performed with UHPLC-MS/MS. The major cytochrome P450 (CYP) enzymes that catalyze skatole degradation in the liver were tested by using RT-PCR and Western blot. Effects of major bioactive compounds in mulberry leaves on the CYP genes were verified in the hepatic cell line HepG2 in an in vitro test (n = 3). In finishing pigs, mulberry leaf supplementation had no significant effect on the average daily gain, average daily feed intake, and feed conversion ratio (P > 0.05), but reduced skatole levels in feces, serum, and backfat (P < 0.05), and increased acetic acid levels in feces (P = 0.027). Mulberry leaf supplementation decreased the relative abundance of the skatole-producing bacteria Megasphaera and Olsenella (P < 0.05). Indole-3-acetic acid, the intermediate that is essential for skatole production, was significantly reduced in feces by mulberry leaf supplementation (P < 0.05) and was positively correlated with skatole content in feces (P = 0.004). In pigs treated with mulberry leaves, liver CYP1A1 expression was increased (P < 0.05) and was negatively correlated with skatole content in backfat (P = 0.045). The in vitro test demonstrated that mulberry leaf polyphenols and polysaccharides could directly stimulate CYP1A1 expression in hepatic cells. These findings suggest that mulberry leaf supplementation reduces skatole production and deposition in finishing pigs by regulating the gut microbiota and promoting skatole degradation in liver.

A 12-week feeding trial with juvenile red drum (Sciaenops ocellatus) fed high-soybean meal (SBM) diets was conducted to investigate a putative biomarker of nutritional imbalance, N-formimino-L-glutamate (FIGLU). Three fishmeal-free, 60% SBM pelleted diets (named B12, Fol, and Met, respectively) were tested to evaluate the effects on growth performance and tissue metabolite profiles of supplementation of vitamin B₁₂ (0.012 mg/kg), folate (10 mg/kg), methionine (1 g/kg) respectively, above basal supplementation levels. A fourth SBM-based diet (named B12/Fol/Met) was formulated with a combination of B₁₂, folate, and methionine to attain the above-mentioned target concentrations. A fifth 60% SBM diet (named FWS) with methionine supplementation (1 g/kg above basal supplementation levels), enriched with taurine, lysine and threonine as well as minerals, was also tested. This diet contained formulation targets and additives which have allowed for replacing fishmeal with plant proteins in rainbow trout feeds. Control diets included a fishmeal-based diet (named FM), an unsupplemented basal 60% SBM diet (named SBM60), and a “natural” diet (named N) made up of equal parts of fish (cigar minnows), squid and shrimp as a positive reference for growth performance. Formulated feeds contained approximately 37% total crude protein, approximately 14% total crude lipid and were energetically balanced. Standard growth performance metrics were measured, and tissues (liver, muscle) were collected at week 12 to evaluate diet-induced metabolic changes using nuclear magnetic resonance (NMR)-based metabolomics. Our results show that the FWS diet outperformed all other SBM diets and the FM diet under all performance metrics (P < 0.05). FIGLU was not detected in fish fed the N diet but was detected in those fed the SBM diets and the FM diet. Fish fed the FWS diet and the Met diet showed lower hepatic levels of FIGLU compared with the other SBM-based diets (P < 0.05), suggesting that among the different supplementation regimes, methionine supplementation was associated with lower FIGLU levels. The FWS diet produced tissue metabolite profiles that were more similar to those of fish fed the N diet. Based on our results, the FWS diet constitutes a promising SBM-based alternative diet to fishmeal for red drum.

Different energy systems have been proposed for energy evaluation of feeds for domestic animals. The oldest and most commonly used systems take into account the fecal energy loss to obtain digestible energy (DE), and fecal, urinary and fermentation gases energy losses to calculate metabolizable energy (ME). In the case of ruminants and pigs, the net energy (NE) system, which takes into account the heat increment associated with the metabolic utilization of ME, has progressively replaced the DE and ME systems over the last 50 years. For poultry, apparent ME (AME) is used exclusively and NE is not yet used widely. The present paper considers some important methodological points for measuring NE in poultry feeds and summarizes the available knowledge on NE systems for poultry. NE prediction equations based on a common analysis of three recent studies representing a total of 50 complete and balanced diets fed to broilers are proposed; these equations including the AME content and easily available chemical indicators have been validated on another set of 30 diets. The equations are applicable to both ingredients and complete diets. They rely primarily on an accurate and reliable AME value which then represents the first limiting predictor of NE value. Our analysis indicates that NE would be a better predictor of broiler performance than AME and that the hierarchy between feeds is dependent on the energy system with a higher energy value for fat and a lower energy value for protein in an NE system. Practical considerations for implementing such an NE system from the commonly used AME or AME_n (AME adjusted for zero nitrogen balance) systems are presented. In conclusion, there is sufficient information to allow the implementation of the NE concept in order to improve the accuracy of feed formulation in poultry.

Heat stress adversely affects sows' performance, which can be improved by applying proper nutritional strategies. This study was conducted to investigate the interactive effects of dietary fiber levels and sources on sows' reproductive performance, metabolic response during gestation, and the carry-over influence on litter performance in the lactation period during heat stress (average room temperature of 27.1 °C). Fifty-four multiparous sows (Landrace × Yorkshire; initial body weight of 236.3 ± 16 kg; 2, 3 and 4 parities) at d 90 of gestation were assigned to a 2 × 3 factorial arrangement (9 sows/treatment), involving 2 dietary fiber levels (4.5% and 6% crude fiber) and 3 dietary fiber sources (wheat bran [WB], palm kernel meal [PK], and beet pulp [BP]). Sows fed the BP diet had highest (P < 0.01) feed intake and constipation index and lowest (P < 0.01) farrowing duration. Piglet weight (P = 0.041) and litter weight (P < 0.01) at weaning were higher in sows in the BP treatment compared to PK treatment. Sows in the BP treatment showed the greatest (P < 0.01) digestibility of crude protein and neutral detergent fiber. The fecal concentration of acetate was the lowest (P < 0.01) in the PK treatment. Total short-chain fatty acid production was increased in the WB and BP treatments compared with the PK. Sows in the BP treatment showed the lowest (P = 0.036) hair cortisol. The blood insulin concentration of sows was higher (P = 0.026) in the high fiber (6%) treatment compared with the low fiber (4.5%) treatment at 90 min and 120 min after the meal. The concentration of phthalic acid, succinic acid, phenylethylamine, hydrocinnamic acid, iron, linoleic acid, glycerol, ketone, and formamide were increased (P < 0.05) in the BP treatment compared with the WB. The BP treatment with high soluble fiber content improved the constipation index, farrowing duration, and litter performance, while high insoluble fibers increased sows comfort and reduced stress factors including respiratory rate and rectal temperature. Therefore, both soluble and insoluble sources of fiber are necessary to be added to the diet of gestating sows.

This research was to assess the dietary copper (Cu) requirement of broiler chickens fed a practical corn-soybean meal diet during 22–42 d of age. A total of 288 numbered Arbor Acres male broilers at 22 d of age were randomly allotted 6 treatments with 8 replicate cages (6 broilers per cage) per treatment. Broilers were fed a Cu-unsupplemented corn-soybean meal basal diet (control, containing 7.36 mg Cu/kg) or the basal diet added with 3, 6, 9, 12, or 15 mg Cu/kg from CuSO₄•5H₂O for 21 d. Quadratic, asymptotic and broken-line models were fitted and the best fitted models were selected to determine dietary Cu requirements. The results revealed that the contents of Cu in serum and liver, mRNA expression levels of Cu- and zinc-containing superoxide dismutase (CuZnSOD) in liver and monoamine oxidase b (MAO B) in heart, as well as protein expression level of CuZnSOD in liver were affected (P < 0.05) by supplemental Cu levels, and the above indices varied linearly and quadratically (P < 0.05) with increasing Cu levels. Dietary Cu requirements assessed according to the best fitted broken-line models (P < 0.05) of the above indexes were 10.45–13.81 mg/kg. It was concluded that mRNA expression levels of CuZnSOD in liver and MAO B in heart, as well as liver CuZnSOD protein expression level were new specific sensitive biomarkers for estimating dietary Cu requirements, and the dietary Cu requirement was recommended to be 14 mg/kg to support Cu metabolic needs related to key Cu-containing enzymes in broilers fed the corn-soybean meal diet during 22–42 d of age, which was higher than the dietary Cu requirement (8 mg/kg) for broilers at the corresponding stage suggested by the Chinese Feeding Standard of Chicken.

Low-fishmeal and protein-saving diets are two prominent nutritional strategies utilized to address challenges related to the scarcity and sustainability of protein sources in aquaculture. However, these diets have been associated with adverse effects on the growth performance, feed utilization, and disease resistance of aquatic animals. To mitigate these challenges, exogenous protease has been applied to enhance the quality of diets with lower protein contents or fishmeal alternatives, thereby improving the bioavailability of nutritional ingredients. Additionally, protease preparations were also used to enzymatically hydrolyze fishmeal alternatives, thus enhancing their nutritional utilization. The present review aims to consolidate recent research progress on the use of protease in aquaculture and conclude the benefits and limitations of its application, thereby providing a comprehensive understanding of the subject and identifying opportunities for future research.

Animal nutritionists have incessantly worked towards providing livestock with high-quality plant protein feed resources. Soybean meal (SBM) has been an essential and predominantly adopted vegetable protein source in livestock feeding for a long time; however, several SBM antinutrients could potentially impair the animal's performance and growth, limiting its use. Several processing methods have been employed to remove SBM antinutrients, including fermentation with fungal or bacterial microorganisms. According to the literature, fermentation, a traditional food processing method, could improve SBM's nutritional and functional properties, making it more suitable and beneficial to livestock. The current interest in health-promoting functional feed, which can enhance the growth of animals, improve their immune system, and promote physiological benefits more than conventional feed, coupled with the ban on the use of antimicrobial growth promoters, has caused a renewed interest in the use of fermented SBM (FSBM) in livestock diets. This review details the mechanism of SBM fermentation and its impacts on animal health and discusses the recent trend in the application and emerging advantages to livestock while shedding light on the research gap that needs to be critically addressed in future studies. FSBM appears to be a multifunctional high-quality plant protein source for animals. Besides removing soybean antinutrients, beneficial bioactive peptides and digestive enzymes are produced during fermentation, providing probiotics, antioxidants, and immunomodulatory effects. Critical aspects regarding FSBM feeding to animals remain uncharted, such as the duration of fermentation, the influence of feeding on digestive tissue development, choice of microbial strain, and possible environmental impact.

This study evaluated the effects of flavonoids from mulberry leaves (FML) on plasma biochemical indices, serum activities of lipid metabolism-related enzymes, fat morphology, fatty acid composition, and lipid metabolism in different adipose tissues of finishing pigs. We used 120 Chinese hybrid barrows of Berkshire and Bama mini-pigs with an average initial body weight of 45.11 ± 4.23 kg. The pigs were randomly assigned to five treatment groups and fed a control diet based on corn, soybean meal, and wheat bran or a control diet supplemented with 0.02%, 0.04%, 0.08%, or 0.16% FML. Each experimental group had six replicates (pens), with four pigs per pen. After a 7-d adaptation period, the feeding trial was conducted for 58 d. Blood and adipose tissue samples were collected from 30 pigs (one pig per pen) at the end of the test. The results showed that FML supplementation significantly decreased the feed intake to body gain ratio, the plasma concentrations of total cholesterol and free fatty acids, and the serum activity of 3-hydroxy-3-methylglutaryl coenzyme A reductase (linear or quadratic effects, P < 0.05), and decreased the plasma triglyceride concentration (quadratic, P = 0.07). Increasing FML supplementation increased the average daily gain and serum activities of lipoprotein lipase (linear and quadratic effects, P < 0.05) and adipose triglyceride lipase (linear, P < 0.05). Dietary FML supplementation decreased the adipocyte area in the dorsal subcutaneous adipose (DSA) tissue of finishing pigs (linear, P = 0.05) and increased the adipocyte area in the visceral adipose tissue (quadratic, P < 0.01). Increasing FML supplementation decreased the C20:1 content in DSA, abdominal subcutaneous adipose, and visceral adipose tissues of finishing pigs (P < 0.05) and increased the C18:3n3 and n-3 PUFA contents (P < 0.05). The lipid metabolism genes were regulated by the PPARγ-LXRα-ABCA1 signaling pathway, and their expressions differed in different adipose tissues. These findings suggest that FML improved growth performance, regulated lipid metabolism, inhibited fat production, and improved fatty acid distribution in the adipose tissue of finishing pigs, thereby improving pig fat's nutritional quality and health value.

This study was conducted to explore the regulatory mechanism of leucine (Leu) on lipid metabolism of finishing pigs. Twenty-four Duroc × Landrace × Large cross pigs with an average body weight of 68.33 ± 0.97 kg were randomly allocated into 3 treatment groups with 8 replicates per group (1 pig per replicate). The dietary treatments were as follows: control group (CON), 0.25% Leu group and 0.50% Leu group. The experimental period was 42 d. The results showed as follows. (1) Compared with the CON, 0.25% and 0.50% Leu increased (P < 0.01) the average daily gain (ADG), while the average backfat thickness (ABT) and the ratio of feed intake to body weight gain (F:G ratio) were decreased (P < 0.05). (2) In the 0.25% Leu group, the relative mRNA expression levels of sterol regulatory element binding protein-1c (SREBP1c), recombinant fatty acid transport protein 1 (FATP1), chemerin and peroxisome proliferator-activated receptor γ (PPARγ) were decreased but the level of fatty acid binding protein 4 (FABP4) and fatty acid translocase (FAT/CD36) were increased in backfat tissue. In the 0.25% Leu group, the protein levels of p-Rictor, p-Raptor, p-eIF4E-binding protein 1 (p-4EBP1), p-silent mating type information regulator 2 homolog 1 (p-SIRT1) and acetylation ribosome s6 protein kinase 1 (Ac–S6K1) were increased (P < 0.05). (3) Compared to the CON, the diversity of gut microbiota in the 0.25% Leu group was increased. Principal component analysis showed that the relative abundance of Bacteroidetes, Lactobacillus and Desulfovibrio was higher in the 0.25% Leu group than the CON, but the relative abundance of Firmicutes, Treponema and Shigella was lower than in the CON (P < 0.05). (4) Four different metabolites were screened out from the serum of finishing pigs including allolithocholic acid (alloLCA), isolithocholic acid (isoLCA), ursodeoxycholic acid (UDCA) and hyodeoxycholic acid (HDCA), which correlate to various degrees with the above microorganisms. In conclusion, Leu could promote adipose tissue lipolysis of finishing pigs through the mTOR-SIRT1 signaling pathway, and S6K1 is acetylated at the same time, and the interaction between gut microbiota and bile acid metabolism is also involved.

Optimal intestinal health and functionality are essential for animal health and performance, and simultaneously intestinal nutrient transporters and intestinal peptides are also involved in appetite and feed intake control mechanisms. Given the potential of essential oil (EO) in improving animal performance and improving feed palatability, we hypothesized that dietary supplementation of cinnamaldehyde and carvacrol could improve performance and appetite of nursery pigs by modulating intestinal health and microbiota. Cinnamaldehyde (100 mg/kg), carvacrol (100 mg/kg), and their mixtures (including 50 mg/kg cinnamaldehyde and 50 mg/kg carvacrol) were supplemented into the diets of 240 nursery pigs for 42 d, and data related to performance were measured. Thereafter, the influence of EO on intestinal health, appetite and gut microbiota and their correlations were explored. EO supplementation increased (P < 0.05) the body weight, average daily gain (ADG) and average daily feed intake (ADFI) of piglets, and reduced (P < 0.05) diarrhea rates in nursery pigs. Furthermore, EO increased (P < 0.05) the intestinal absorption area and the abundance of tight junction proteins, and decreased (P < 0.05) intestinal permeability and local inflammation. In terms of intestinal development and the mucus barrier, EO promoted intestinal development and increased (P < 0.05) the number of goblet cells. Additionally, we found that piglets in the EO-supplemented group had upregulated (P < 0.05) levels of transporters and digestive enzymes in the intestine, which were significantly associated with daily gain and feed utilization. In addition, EO supplementation somewhat improved appetite in nursery pigs, increased the diversity of the gut microbiome and the abundance of beneficial bacteria, and there was a correlation between altered bacterial structure and appetite-related hormones. These findings indicate that EO is effective in promoting growth performance and nutrient absorption as well as in regulating appetite by improving intestinal health and bacterial structure.

The production of selenium-enriched fish can contribute to alleviating selenium deficiency in human diets. However, it is still unclear which selenium source, as an additive, can efficiently and cost-effectively produce high-quality selenium-enriched fish. This study evaluated the effects of selenium nanoparticles (SeNP), selenite, and selenomethionine (SeMet) on the growth, antioxidant capacity, selenium content, selenium speciation, and meat quality of grass carp. Ten diets were prepared, including a basal diet (BD) and three concentrations (0.1, 0.3, and 0.9 mg/kg) of SeNP, selenite, and SeMet. A total of 600 fish (250.79 ± 1.57 g) were randomly assigned to 30 tanks (3 tanks/group). Fish were fed the experimental diet three times daily for 60 d. In this study, SeNP most significantly promoted the growth and antioxidant capacity of grass carp, with 0.3 mg/kg SeNP identified as the optimal additive concentration. Additionally, SeNP demonstrated equally excellent bioavailability as SeMet and significantly increased the content of SeMet in grass carp (Ctenopharyngodon idella) muscle. Furthermore, compared to SeMet and selenite, dietary SeNP could more significantly enhance the content of selenocysteine (SeCys₂) and methylselenocysteine (MeSeCys) in grass carp muscle tissue. In addition, we have demonstrated that SeCys₂ and MeSeCys promote apoptosis of cancer cells (HeLa) through the mitochondrial apoptotic pathway (involving Bax and Bcl-2). Furthermore, as an additive, 0.3 mg/kg SeNP significantly improved the flesh quality of grass carp by reducing crude fat and heavy metal content, as well as increasing the levels of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) and the ratio of n-3/n-6 polyunsaturated fatty acid (PUFA). In summary, SeNP is the most suitable additive for producing selenium-enriched fish.

Bacterial pathogens destroy the structural integrity of functional organs in fish, leading to severe challenges in the aquaculture industry. Vitamin D₃ (VD₃) prevents bacterial infections and strengthens immune system function via vitamin D receptor (VDR). However, the correlation between VD₃/VDR and the structural integrity of functional organs remains unclarified. This study aimed to investigate the influence of VD₃ supplementation on histological characteristics, apoptosis, and tight junction characteristics in fish intestine during pathogen infection. A total of 540 healthy grass carp (257.24 ± 0.63 g) were fed different levels of VD₃ (15.2, 364.3, 782.5, 1,167.9, 1,573.8, and 1,980.1 IU/kg) for 70 d. Subsequently, fish were challenged with Aeromonas hydrophila, a pathogen that causes intestinal inflammation. Our present study demonstrated that optimal supplementation with VD₃ (1) alleviated intestinal structural damage, and inhibited oxidative damage by reducing levels of oxidative stress biomarkers; (2) attenuated excessive apoptosis-related death receptor and mitochondrial pathway processes in relation to p38 mitogen-activated protein kinase signaling (P < 0.05); (3) enhanced tight junction protein expression by inhibiting myosin light chain kinase signaling (P < 0.05); and (4) elevated VDR isoform expression in fish intestine (P < 0.05). Overall, the results demonstrated that VD₃ alleviates oxidative injury, apoptosis, and the destruction of tight junction protein under pathogenic infection, thereby strengthening pathogen defenses in the intestine. This finding supports the rationale for VD₃ intervention as an essential practice in sustainable aquaculture.

Methionine (Met) is an essential and first limiting amino acid in the poultry diet that plays a significant role in chicken embryonic development and growth. The present study examined the effect of in ovo injection of DL-Met and L-Met sources and genotypes on chicken embryonic-intestinal development and health. Fertilized eggs of the two genotypes, TETRA-SL layer hybrid (TSL) — commercial layer hybrid and Hungarian Partridge colored hen breed (HPC) — a native genotype, were randomly distributed into four treatments for each genotype. The treatment groups include the following: 1) control non-injected eggs (NoIn); 2) saline-injected (SaIn); 3) DL-Met injected (DLM); and 4) L-Met injected (LM). The in ovo injection was carried out on 17.5 d of embryonic development; after hatching, eight chicks per group were sacrificed, and the jejunum was extracted for analysis. The results showed that both DLM and LM groups had enhanced intestinal development as evidenced by increased villus width, villus height, and villus area (P < 0.05) compared to the control. The DLM group had significantly reduced crypt depth, glutathione (GSH) content, glutathione S-transferase 3 alpha (GST3), occludin (OCLN) gene expression and increased villus height to crypt depth ratio in the TSL genotype than the LM group (P < 0.05). The HPC genotype has overexpressed insulin-like growth factor 1 (IGF1) gene, tricellulin (MD2), occludin (OCLN), superoxide dismutase 1 (SOD1), and GST3 genes than the TSL genotype (P < 0.05). In conclusion, these findings showed that in ovo injection of Met enhanced intestinal development, and function, with genotypes responding differently under normal conditions. Genotypes also influenced the expression of intestinal antioxidants, tight junction, and growth-related genes.

Net energy (NE) enables the prediction of more accurate feed energy values by taking into account the heat increment which is approximately 25% of apparent metabolizable energy (AME) in poultry. Nevertheless, application of NE in poultry industry has not been practiced widely. To predict the NE values of broiler diets, 23 diets were prepared by using 13 major ingredients (wheat, corn, paddy rice, broken rice, cassava pellets, full-fat soybean, soybean meal, canola meal, animal protein, rice bran, wheat bran, palm kernel meal and palm kernel oil). The diets were formulated in order to meet the birds' requirements and get a wide range of chemical compositions (on DM basis; 33.6% to 55.3% for starch; 20.8% to 28.4% for CP, 2.7% to 10.6% for ether extract [EE] and 7.0% to 17.2% for NDF), with low correlations between these nutrients and low correlations between the inclusion levels of ingredients allowing for the calculation of robust prediction equations of energy values of diets or ingredients. These diets were fed to Ross 308 broilers raised in 12 open-circuit respiratory chambers from 18 to 23 d of age (4 birds per cage) and growth performance, diet AME content and heat production were measured, and dietary NE values were calculated. The trial was conducted on a weekly basis with 12 diets measured each week (1 per chamber), 1 of the 23 diets (reference diet) being measured each week. Each diet was tested at least 8 times. In total, 235 energy balance data values were available for the final calculations. Growth performance, AME (15.3 MJ/kg DM on average) and AME/GE (79.4% on average) values were as expected. The NE/AME value averaged 76.6% and was negatively influenced by CP and NDF and positively by EE in connection with efficiencies of AME provided by CP, EE and starch for NE of 73%, 87% and 81%, respectively. The best prediction equation was: NE = (0.815 × AME) — (0.026 × CP) + (0.020 × EE) — (0.024 × NDF) with NE and AME as MJ/kg DM, and CP, EE and NDF as % of DM. The NE prediction equations from this study agree with other recently reported equations in poultry and are suitable for both ingredients and complete feeds.

T-2 toxin is one of the most widespread and toxic fungal toxins in food and feed. It can cause gastrointestinal toxicity, hepatotoxicity, immunotoxicity, reproductive toxicity, neurotoxicity, and nephrotoxicity in humans and animals. T-2 toxin is physicochemically stable and does not readily degrade during food and feed processing. Therefore, suppressing T-2 toxin-induced organ toxicity through antidotes is an urgent issue. Protective agents against the organ toxicity of T-2 toxin have been recorded widely in the literature, but these protective agents and their molecular mechanisms of detoxification have not been comprehensively summarized. In this review, we provide an overview of the various protective agents to T-2 toxin and the molecular mechanisms underlying the detoxification effects. Targeting appropriate targets to antagonize T-2 toxin toxicity is also an important option. This review will provide essential guidance and strategies for the better application and development of T-2 toxin antidotes specific for organ toxicity in the future.

Piglet diarrhea is among one of the most serious health problems faced by the pig industry, resulting in significant economic losses. Diarrheal disease in piglets has a multifactorial etiology that is affected by physiology, environment, and management strategy. Diarrhea is the most apparent symptom of intestinal dysfunction. As a key class of essential nutrients in the piglet diet, amino acids confer a variety of beneficial effects on piglets in addition to being used as a substrate for protein synthesis, including maintaining appropriate intestinal integrity, permeability and epithelial renewal, and alleviating morphological damage and inflammatory and oxidative stress. Thus, provision of appropriate levels of amino acids could alleviate piglet diarrhea. Most amino acid effects are mediated by metabolites, gut microbes, and related signaling pathways. In this review, we summarize the current understanding of dietary amino acid effects on gut health and diarrhea incidence in piglets, and reveal the mechanisms involved. We also provide ideas for using amino acid blends and emphasize the importance of amino acid balance in the diet to prevent diarrhea in piglets.

Vitamin E (VE) is an essential lipid-soluble vitamin that improves the fish flesh quality. However, the underlying molecular mechanisms remain unclear. This study aimed to investigate the effects of VE on growth performance and flesh quality in sub-adult grass carp (Ctenopharyngodon idella). A total of 450 fish (713.53 ± 1.50 g) were randomly divided into six treatment groups (three replicates per treatment) and fed for nine weeks with different experimental diets (dietary lipid 47.8 g/kg) that contained different levels of VE (5.44, 52.07, 96.85, 141.71, 185.66, and 230.12 mg/kg diet, supplemented as dl-α-tocopherol acetate). Notably, the treatment groups that were fed with dietary VE ranging from 52.07 to 230.12 mg/kg diet showed improvement in the percent weight gain, special growth rate, and feed efficiency of grass carp. Moreover, the treatment groups supplemented with dietary VE level of 141.71, 185.66, and 230.12 mg/kg diet showed enhancement in crude protein, lipid, and α-tocopherol contents in the muscle, and the dietary levels of VE ranging from 52.07 to 141.71 mg/kg diet improved muscle pH_24h and shear force but reduced muscle cooking loss in grass carp. Furthermore, appropriate levels of VE (52.07 to 96.85 mg/kg diet) increased the muscle polyunsaturated fatty acid content in grass carp. Dietary VE also increased the mRNA levels of fatty acid synthesis-related genes, including fas, scd-1, fad, elovl, srebp1, pparγ, and lxrα, and up-regulated the expression of SREBP-1 protein. However, dietary VE decreased the expression of fatty acid decomposition-related genes, including hsl, cpt1, acox1, and pparα, and endoplasmic reticulum stress-related genes, including perk, ire1, atf6, eif2α, atf4, xbp1, chop, and grp78, and down-regulated the expression of p-PERK, p-IRE1, ATF6, and GRP78 proteins. In conclusion, dietary VE increased muscle fatty acid synthesis, which may be partly associated with the alleviation of endoplasmic reticulum stress, and ultimately improves fish flesh quality. Moreover, the VE requirements for sub-adult grass carp (713.53 to 1590.40 g) were estimated to be 124.9 and 122.73 mg/kg diet based on percentage weight gain and muscle shear force, respectively.

The global trend towards raising broiler chickens without the use of in-feed antibiotics (IFAs) means that there is an ongoing need to develop alternative treatments capable of delivering the benefits that IFAs previously provided. IFAs supported the productivity performance of chickens and played a key role in maintaining their health. Necrotic enteritis (NE) is an important disease of broilers that affects health, productivity, and welfare, and was previously well controlled by IFAs. However, with the reduction in IFA use, NE is resurgent in some countries. Vaccines and various feed additives, including pre-, pro-, and postbiotics, phytobiotics, fatty acids, and phage therapies have been introduced as alternative methods of NE control. While some of these feed additives have specific activity against the NE pathogen, Clostridium perfringens, most have the more general goal of reinforcing gut health. Extensive reviews of the effects of many of these feed additives on gut health have been published recently. Hence, rather than cover previously well reviewed areas of research this review focuses on the challenges and pitfalls in undertaking experimental assessment of alternative NE treatments and translating laboratory research to real world commercial production settings. The review is based on the author's particular experience, reading, thoughts, and analysis of the available information and inevitably presents a particular understanding that is likely to be at odds with others thinking on these issues. It is put forward to stimulate thinking and discussion on the issues covered.

Fat is one of the three macronutrients and a significant energy source for piglets. It plays a positive role in maintaining intestinal health and improving production performance. During the weaning period, physiological, stress and diet-related factors influence the absorption of fat in piglets, leading to damage to the intestinal barrier, diarrhea and even death. Signaling pathways, such as fatty acid translocase (CD36), pregnane X receptor (PXR), and AMP-dependent protein kinase (AMPK), are responsible for regulating intestinal fat uptake and maintaining intestinal barrier function. Therefore, this review mainly elaborates on the reasons for diarrhea induced by insufficient fat absorption and related signaling pathways in weaned-piglets, with an emphasis on the intestinal fat absorption disorder. Moreover, we focus on introducing nutritional strategies that can promote intestinal fat absorption in piglets with insufficient fat absorption-related diarrhea, such as lipase, amino acids, and probiotics.

The present study was to explore the Ile requirement of piglets fed 18% crude protein (CP) diets. Two hundred and fifty 28-day-old Duroc × Landrace × Yorkshire piglets (8.37 ± 1.92 kg) were randomly divided into 5 dietary treatments (10 piglets per replicate, 5 barrows and 5 gilts per replicate) with 45%, 50%, 55%, 60%, 65% standardized ileal digestible (SID) Ile-to-Lys ratios, and the SID Lys was formulated to 1.19%. The experimental design consisted of two phases (d 1 to 14 and d 15 to 28). Results showed that average daily gain (ADG) had a tendency to quadratically increase as the SID Ile-to-Lys ratio increased (P = 0.09), and the optimum SID Ile-to-Lys ratios required to maximize ADG were 48.33% and 54.63% for broken-line linear model and quadratic polynomial model, respectively. Different SID Ile-to-Lys ratios had no significant effects on average daily feed intake and gain-to-feed ratio. Dry matter (P < 0.01), CP (P = 0.01), ether extract (P = 0.04), gross energy (P < 0.01) and organic matter (P < 0.01) digestibility increased quadratically. Serum total cholesterol levels decreased linearly (P = 0.01) and quadratically (P < 0.01); aspartate aminotransferase (P < 0.01), interleukin-1β (P = 0.01), and tumor necrosis factor-α (P < 0.01) levels decreased quadratically; immunoglobulin G (P = 0.03) and immunoglobulin M (P = 0.01) concentrations increased quadratically. Serum Ser levels decreased linearly (P < 0.01) and quadratically (P = 0.01); Glu (P = 0.02), Arg (P = 0.05), and Thr (P = 0.03) levels decreased quadratically; Gly (P < 0.01) and Leu (P = 0.01) levels decreased linearly; Ile (P < 0.01) concentration increased linearly. Duodenal villus height (P < 0.01) and villus height to crypt depth ratio (P < 0.01) increased quadratically. The deficiency or excess of Ile decreased short chain fatty acid-producing bacteria abundance and increased pathogenic bacteria abundance. Overall, taking ADG as the effect index, the optimum SID Ile-to-Lys ratios of piglets offered 18% CP diets were 48.33% and 54.63% based on two different statistical models, respectively, and the deficiency or excess of lle negatively affected piglet growth rates and health status.

This study was to investigate growth performance, rumination development, rumen fermentation and feed digestion in young calves provided high volumes (about 20% of calf birth weight) of milk with or without forage inclusion and how these parameters correlate with each other. Immediately after birth, 160 newborn Holstein female calves (41.6 ± 4.2 kg of initial BW) were randomly divided into 2 treatments: 1) starter (CON, only starter) and 2) starter and hay (HAY, both starter and hay). The calves were fed their respective experimental diets from d 4 to 84, after which they were all introduced to similar diets until the end of the experiment on d 196. Treatment had no effect on growth and structural measurements throughout the experimental period. However, treatment had an effect on the other parameters, mainly during the post-weaning period. Forage supplementation tended to reduce starter dry matter intake (P = 0.05), while increasing the forage intake (P < 0.01) and the feed-to-gain ratio (P < 0.01). HAY calves had increased neutral detergent fiber (NDF) and physically effective NDF (peNDF) intakes (P < 0.05) and tended to lower (P < 0.01) starch intake compared to CON calves. The HAY calves had a higher rumination time (P < 0.01), ruminal pH (P < 0.01), and acetate-to-propionate ratio (P = 0.05) compared to the CON calves. Spearman correlation analysis showed that rumination time was positively related to the ruminal pH at d 84 (P = 0.01) and 196 (P = 0.02). The HAY calves had similar apparent total-tract digestibility of dry matter (DM), NDF and ether extract (EE), but lower digestibility of organic matter (OM, P = 0.03), crude protein (CP, P < 0.01) and starch (P < 0.01) compared to those of the CON calves at week 12. Furthermore, there were no positive relationships between rumination time and nutrient digestibility or between rumination time per kilogram DM and nutrient digestibility. In conclusion, feeding hay to calves fed a high milk level improved rumination during the post-weaning period only, without a concomitant effect on growth performance throughout the experimental period, suggesting no detrimental effect of feeding forage in calves fed high milk level.

Glucose plays a vital part in milk protein synthesis through the mTOR signaling pathway in bovine mammary epithelial cells (BMEC). The objectives of this study were to determine how glucose affects hexokinase (HK) activity in BMEC and investigate the regulatory effect of HK in kappa casein (CSN3) synthesis via the mechanistic target of rapamycin complex 1 (mTORC1) signaling pathway in BMEC. For this, HK1 and HK2 were knocked out in BMEC using the CRISPR/Cas9 system. The gene and protein expression, glucose uptake, and cell proliferation were measured. We found that glucose uptake, cell proliferation, CSN3 gene expression levels, and expression of HK1 and HK2 increased with increasing glucose concentrations. Notably, glucose uptake was significantly reduced in HK2 knockout (HK2KO) BMEC treated with 17.5 mM glucose. Moreover, under the same glucose treatment conditions, the proliferative ability and abundance of CSN3 were significantly diminished in both HK1 knockout (HK1KO) and HK2KO BMEC compared with that in wild-type BEMC. We further observed that the phosphorylation levels of ribosome protein subunit 6 kinase 1 (S6K1) were reduced in HK1KO and HK2KO BMEC following treatment with 17.5 mM glucose. As expected, the levels of glucose-6-phosphate and the mRNA expression levels of glycolysis-related genes were decreased in both HK1KO and HK2KO BMEC following glucose treatment. These results indicated that the knockout of HK1 and HK2 inhibited cell proliferation and CSN3 expression in BMEC under glucose treatment, which may be associated with the inactivation of the S6K1 and inhibition of glycolysis.

The compromised egg quality and leg abnormality during the end of the laying cycle (after 40 weeks) have been leading to poor animal welfare and substantial economic losses. Therefore, the effects of fermented calcium (Ca) butyrate, produced by fermentation by Clostridium butyricum, on production, eggshell quality, and tibial property of hens were explored. A total of 192 Hy-line brown laying hens at 50-week-old were assigned to a basal diet or the basal diet with 300 mg/kg of the fermented Ca butyrate from 50 to 58 weeks of age. Each treatment had 6 replicates with 16 hens each. The diet supplemented with 300 mg/kg fermented Ca butyrate notably increased egg weight, ovarian follicle number, and eggshell strength (P = 0.072) as compared to the basal diet, which were associated with cytokine secretion, toll-like receptor signaling pathways, and intestinal immunity based on the RNA-seq data from the granulosa. Dietary Ca butyrate inclusion decreased the expression of ileal tumor necrosis factor-alpha and serum pro-inflammatory cytokine concentration, as well as increased the content of serum immunoglobulin A when compared to the basal diet (both P < 0.05). The birds that received fermented Ca butyrate diets exhibited higher villus height (P < 0.05) and upregulated expression of tight junction proteins, whereas it did not alter the composition of cecal microbiota (P > 0.05). In addition, the diet with fermented Ca butyrate reduced the number of osteoclasts in the proximal tibia and the level of C-terminal cross-linked telopeptide of type I collagen, a bone resorption marker (P < 0.05), whereas it tended to increase the concentration of the procollagen type I N-terminal propeptide that reflects bone formation marker in serum. Moreover, the layers fed fermented Ca butyrate diets possessed higher (P < 0.05) bone area and trabecular number of the proximal tibia, yield load, and ultimate load than those that consumed basal diets. Collectively, dietary fermented Ca butyrate supplementation in post-peak layer diets improved the ovarian function and tibia quality, which might be related to enhancing intestinal integrity and consequently decreasing inflammation mediated bone resorption.

In the present study, the chronic heat stress (CHS) broiler model was developed to investigate the potential protection mechanism of organic selenium (selenomethionine, SeMet) on CHS-induced skeletal muscle growth retardation and poor meat quality. Four hundred Arbor Acres male broilers (680 ± 70 g, 21 d old) were grouped into 5 treatments with 8 replicates of 10 broilers per replicate. Broilers in the control group were raised in a thermoneutral environment (22 ± 2 °C) and fed with a basal diet. The other four treatments were exposed to hyperthermic conditions (33 ± 2 °C, 24 h in each day) and fed on the basal diet supplied with SeMet at 0.0, 0.2, 0.4, and 0.6 mg Se/kg, respectively, for 21 d. Results showed that CHS reduced (P < 0.05) the growth performance, decreased (P < 0.05) the breast muscle weight and impaired the meat quality of breast muscle in broilers. CHS induced protein metabolic disorder in breast muscle, which increased (P < 0.05) the expression of caspase 3, caspase 8, caspase 9 and ubiquitin proteasome system related genes, while decreased the protein expression of P-4EBP1. CHS also decreased the antioxidant capacity and induced mitochondrial stress and endoplasmic reticulum (ER) stress in breast muscle, which increased (P < 0.05) the ROS levels, decreased the concentration of ATP, increased the protein expression of HSP60 and CLPX, and increased (P < 0.05) the expression of ER stress biomarkers. Dietary SeMet supplementation linearly increased (P < 0.05) breast muscle Se concentration and exhibited protective effects via up-regulating the expression of the selenotranscriptome and several key selenoproteins, which increased (P < 0.05) body weight, improved meat quality, enhanced antioxidant capacity and mitigated mitochondrial stress and ER stress. What's more, SeMet suppressed protein degradation and improved protein biosynthesis though inhibiting the caspase and ubiquitin proteasome system and promoting the mTOR-4EBP1 pathway. In conclusion, dietary SeMet supplementation increases the expression of several key selenoproteins, alleviates mitochondrial dysfunction and ER stress, improves protein biosynthesis, suppresses protein degradation, thus increases the body weight and improves meat quality of broilers exposed to CHS.

This experiment aimed to discuss and reveal the effect and mechanism of mannanase on intestinal inflammation in broilers triggered by a soybean meal diet. In this experiment, 384 Arbor Acres broilers at 1 d old were randomly divided into 3 treatment groups. The broilers were fed a corn-soybean meal basal diet, a low-energy diet (metabolizable energy reduced by 50 kcal/kg), and a low-energy diet supplemented with 100 mg/kg mannanase for 42 d. The low-energy diet increased feed conversion ratio from 0 to 42 d, reduced ileal villus height and villus height-to-crypt depth ratio and upregulated the expression of nuclear factor kappa B (NF-κB) in the ileum (P < 0.05). It also reduced cecal short-chain fatty acids (SCFA), such as acetic acid (P < 0.05). Compared with low-energy diets, the addition of mannanase increased body weight at 42 d, promoted the digestibility of nutrients, and maintained the morphology and integrity of the intestinal epithelium of broilers (P < 0.05). In addition, mannanase upregulated the expression of claudin-1 (CLDN1) and zonula occludens-1 (ZO-1) in the jejunum at 21 d, downregulated the expression of ileal NF-κB, and increased the content of isobutyric acid in the cecum of broilers (P < 0.05). The results for the ileal microbiota showed that a low-energy diet led to a decrease in the relative abundance of Lactobacillus reuteri in the ileum of broilers. The addition of mannanase increased the relative abundance of Lactobacillus-KC45b and Lactobacillus johnsonii in broilers. Furthermore, a low-energy diet reduced the relative abundance of Butyricicoccus in the intestine of broilers and inhibited oxidative phosphorylation and phosphoinositol metabolism. Mannanase increased the relative abundance of Odoribacter, promoted energy metabolism and N-glycan biosynthesis, and increased the activities of GH3 and GH18. It is concluded that mannanase could improve the growth performance of broilers by reducing the expression of NF-κB in the ileum, increasing the production of SCFA in the cecum, suppressing intestinal inflammation, balancing the intestinal microbiota, reducing damage to the intestinal barrier, and improving the efficiency of nutrient utilization to alleviate the adverse effects caused by the decrease in dietary energy level.

The present study was to evaluate the effect of trace minerals (Zn, Mn, and Cu) from complexed amino acid minerals (ZMCAA) and bis-glycinate chelated minerals (ZMCGly) in laying hen diets on performance, internal and external egg quality, yolk mineral deposition, intestinal morphometry, and bone characteristics. From 78 to 98 weeks of age, 400 White LSL-Lite strain laying hens were distributed in a randomized design with 4 treatments with 10 replicates per treatment. Treatments were distributed in a 2 × 2 factorial arrangement using either Zn, Mn, and Cu of ZMCAA or ZMCGly source at 2 levels: low (20, 20, and 3.5 mg/kg of Zn, Mn, and Cu, respectively) or high (40, 40, and 7 mg/kg of Zn, Mn, and Cu, respectively). The analysis of variance was performed, and in cases where differences were observed, the means were compared using Tukey's test (P < 0.05). The source and level of trace mineral supplementation had a significant impact on the performance of laying hens. Hens fed ZMCAA had higher egg production (P = 0.01), egg weight (P = 0.02), egg mass (P = 0.01), and lower feed conversion ratio (P = 0.05) compared to those fed ZMCGly. The ZMCAA supplementation showed higher albumen height (P = 0.01), albumen weight (P = 0.01), and eggshell thickness (P < 0.01). The deposition of Zn (P < 0.01), Mn (P < 0.01), and Cu (P < 0.01) in the egg yolk was greater for hens received ZMCAA. Tibia weight (P = 0.04) and bone densitometry (P < 0.01) in the tibia were higher with ZMCAA supplementation. In the small intestine, ZMCAA resulted in longer villi (P = 0.02) and shorter crypt depth (P = 0.01) in the duodenum. Jejunum and ileum measurements were influenced by the level and source of trace minerals (P < 0.05). Laying hens fed ZMCAA exhibited superior performance, egg quality, deposition of trace minerals in the egg yolk, and bone density compared to hens fed ZMCGly. In this study, older laying hens supplemented with ZMCAA at lower levels demonstrated adequate levels of supplementation.

Rotaviruses (RV) are a major cause of severe gastroenteritis, particularly in neonatal piglets. Despite the availability of effective vaccines, the development of antiviral therapies for RV remains an ongoing challenge. Retinoic acid (RA), a metabolite of vitamin A, has been shown to have anti-oxidative and antiviral properties. However, the mechanism by which RA exerts its intestinal-protective and antiviral effects on RV infection is not fully understood. The study investigates the effects of RA supplementation in Duroc × Landrace × Yorkshire (DLY) piglets challenged with RV. Thirty-six DLY piglets were assigned into six treatments, including a control group, RA treatment group with two concentration gradients (5 and 15 mg/d), RV treatment group, and RV treatment group with the addition of different concentration gradients of RA (5 and 15 mg/d). Our study revealed that RV infection led to extensive intestinal architecture damage, which was mitigated by RA treatment at lower concentrations by increasing the villus height and villus height/crypt depth ratio (P < 0.05), enhancing intestinal stem cell signaling and promoting intestinal barrier functions. In addition, 15 mg/d RA supplementation significantly increased NRF2 and HO-1 protein expression (P < 0.05) and GSH content (P < 0.05), indicating that RA supplementation can enhance anti-oxidative signaling and redox homeostasis after RV challenge. Additionally, the research demonstrated that RA exerts a dual impact on the regulation of autophagy, both stimulating the initiation of autophagy and hindering the flow of autophagic flux. Through the modulation of autophagic flux, RA influence the progression of RV infection. These findings provide new insights into the regulation of redox hemostasis and autophagy by RA and its potential therapeutic application in RV infection.

Phytin is the Ca²⁺-Mg²⁺-K⁺ salt of phytic acid that is created and deposited in the aleurone layer and/or germ of grains and legumes. Its high presence in feedstuffs for fowl and swine diets results in it being a universal and significant impediment to optimum performance. Phytin impairs gastrointestinal recovery of a wide array of nutrients, the effect varying with the nutrient concerned. On exposure to low pH during gastric digestion, phytin dissociates into phytic acid and solubilized Ca²⁺. Even at low gastric pH, phytic acid is negatively charged which forms the basis of its anti-nutritive behavior. Pepsinogen has extensive basic amino acids on its activation peptide that are presented as cations at low pH which are targeted by pepsin for activation. Partially crystalized Ca²⁺ near the enzyme's active site further stabilizes its newly formed structure. Thus, phytic acid appears to interfere with gastric digestion by several mechanisms; interfering with pepsinogen activation by binding to the polypeptide's basic amino acids; coordinating free Ca²⁺, destabilizing pepsin; binding some dietary proteins directly, further compromising gastric proteolysis. Upon digesta attaining neutrality in the duodenum, Ca²⁺ and other cations re-bind with accessible anions, phytic acid being a significant contender. Phytate not only binds free cations but can also strip them from enzymes (e.g. Ca²⁺, Zn²⁺) which reduces their structural resistance to autolysis and ability as co-factors (e.g. Zn²⁺) to increase enzyme activity. Goblet cells initially employ Ca²⁺ as an electronic shield between mucin layers enabling granule formation and cell storage. After mucin granule release, Ca²⁺ is progressively displaced by Na⁺ to free the viscous mucins enabling its translocation. Mucin entangles with the glycocalyx of adjacent enterocytes thereby constructing the unstirred water layer (USWL). Excessive removal of Ca²⁺ from mucin by phytic acid increases its fluidity facilitating its loss from the USWL with its associated Na⁺. This partly explains increased mucin and Na⁺ losses noted with high phytate diets. This review suggests that phytic acid binding of Ca²⁺ and less so Zn²⁺ is the basis for the diversity in nutrient losses encountered and that such losses are in proportion to dietary phytate content.

This study explored the developmental changes in small intestinal barrier function and the potential regulatory roles of intestinal microbiota and metabolites in different breeds of piglets during suckling and weaning periods. Taoyuan black (TB), Xiangcun black (XB), and Duroc (DR) piglets (10 litters per breed; half male and half female) were selected for sampling to evaluate the intestinal barrier-related indexes and intestinal microbiota and metabolites at 1, 10, 21 (weaned), and 24 (3 d after weaning) d old. The results showed that weaning led to severe shedding of small intestinal microvilli and sparse microvilli arrangement. D-lactate level in the ileum of TB and XB piglets during suckling and weaning periods was lower (P < 0.01) than that of DR piglets, as well as the ileal diamine oxidase level at 1 d old. The expression level of mucin 1 was higher (P < 0.05) in the ileum of TB and XB piglets than that of DR piglets, and it was the highest in the ileum of TB piglets at 21 d old. The expression levels of mucin 2 and mucin 13 were higher (P < 0.10) in TB and XB piglets than those of DR piglets at 21 d old, whereas mucin 2 and mucin 13 in the ileum of TB and XB piglets were higher (P < 0.05) than those of DR piglets at 24 d old. TB and XB piglets had a lower relative abundance of Escherichia_Shigella at 21 and 24 d old, but they had higher Streptococcus at 1 and 24 d old than DR piglets (P < 0.01). Differential metabolites between the three breeds of piglets were mainly related to oxidative phosphorylation, steroid biosynthesis, and bile acid synthesis. Collectively, these findings suggest that different pig breeds present differences in the development of the small intestinal barrier function. Compared with DR piglets, TB and XB piglets had higher intestinal permeability during the suckling period and a stronger intestinal mechanical barrier after weaning. Moreover, intestinal microbiota and metabolites are the key factors for developing small intestinal barrier functions in different breeds of piglets.

High-carbohydrate (HC) diets decrease the intestinal levels of sodium acetate (SA) and sodium butyrate (SB) and impair the gut health of largemouth bass; however, SA and SB have been shown to enhance immunity and improve intestinal health in farmed animals. Thus, the present study was to investigate the effects of dietary SA and SB on HC diet-induced intestinal injury and the potential mechanisms in juvenile largemouth bass. The experiment set five isonitrogenous and isolipidic diets, including a low-carbohydrate diet (9% starch) (LC), a high carbohydrate diet (18% starch) (HC), and the HC diet supplemented with 2 g/kg SA (HCSA), 2 g/kg SB (HCSB) or a combination of 1 g/kg SA and 1 g/kg SB (HCSASB). The feeding experiment was conducted for 8 weeks. A total of 525 juvenile largemouth bass with an initial body weight of 7.00 ± 0.20 g were used. The results showed that dietary SA and SB improved the weight gain rate and specific growth rate (P < 0.05) and ameliorated serum parameters (alkaline phosphatase, acid phosphatase, glutamate transaminase, and glutamic oxaloacetic transaminase) (P < 0.05). And, importantly, dietary SA and SB repaired the intestinal barrier by increasing the expression levels of zonula occludens-1, occludin, and claudin-7 (P < 0.05), reduced HC-induced intestinal damage, and alleviated intestinal inflammation and cell apoptosis by attenuating HC-induced intestinal endoplasmic reticulum stress (P < 0.05). Further results revealed that dietary SA and SB reduced HC-induced intestinal fat deposition by inhibiting adipogenesis and promoting lipolysis (P < 0.05). In summary, this study demonstrated that dietary SA and SB attenuated HC-induced intestinal damage and reduced excessive intestinal fat deposition in largemouth bass.