Diarrheas are common risks faced by piglets during the weaning period. This study investigated the alleviating effects of artificial parasin I protein (API) on growth performance and intestinal health of weaned pigs upon enterotoxigenic Escherichia coli (ETEC) challenge. Sixty piglets were randomly divided into five groups and fed a basal diet (CON) or basal diet supplemented with API at 0, 750, and 1500 mg/kg or antibiotics for 5 weeks. On d 15 and 25, piglets were challenged with ETEC K88 except for the CON group. Before the ETEC challenge (d 1–14), dietary API supplementation improved growth performance, and 750 mg API increased (P < 0.05) the average daily gain (ADG), decreased (P < 0.05) feed to gain ratio (F/G) and diarrhea index of weaned piglets. ETEC challenge (during d 15–35) reduced growth performance and increased (P < 0.01) the F/G, diarrhea rate, and diarrhea index. This event was accompanied by the numerically increased malondialdehyde (MDA) levels in serum and ileum, the decreased (P < 0.05) zonula-occludens-1 (ZO-1) and interleukin-6 (IL-6) in the ileum, and the increased (P = 0.04) secretory immunoglobulin A (sIgA) protein in the ileum. Artificial parasin I protein supplementation alleviated the negative impact of ETEC. The 750 mg/kg API inclusion elevated (P < 0.05) ADG and decreased (P < 0.05) F/G. Two levels of API decreased (P < 0.01) the diarrhea rate and diarrhea index. Meanwhile, API inclusion decreased (P < 0.01) the crypt depth in the jejunum, elevated (P < 0.05) villus height in the duodenum and villus height to crypt depth ratio in the duodenum and ileum, up-regulated (P < 0.05) ZO-1 gene, and down-regulated (P < 0.05) mucin-2 gene in the jejunum, and 1500 mg/kg API decreased (P < 0.01) sIgA level and down-regulated (P < 0.05) IL-1β gene in the ileum. Furthermore, 750 mg/kg API elevated (P < 0.01) Bifidobacteria population and acetic acid concentrations in the cecal chyme. In conclusion, API supplementation alleviates the negative impact of ETEC on growth performance and intestinal health, thus can be applied as an antibiotic alternative in weaned piglets.

This review explores the potential of including glutamine, a so-called non-essential amino acid, in the formulation of reduced-crude protein (CP) diets for broiler chickens. There is a precedent for benefits when including glycine and serine in reduced-CP diets. Fundamentally this is due to decreases in non-essential amino acid concentrations in reduced-CP diets — an unavoidable consequence of reducing CP without amino acid supplementation. The situation for glutamine is complicated because analysed dietary concentrations are very rarely provided as standard assays do not differentiate between glutamine and glutamate and are reported on a combined basis as glutamic acid. The dietary requirement for glutamic acid is approximately 36.3 g/kg but it is increasingly unlikely that this requirement will be met as dietary CP levels are progressively reduced. Glutamine is an abundant and versatile amino acid and constitutes 50.5 mg/g of whole-body chicken protein and is the dominant free amino acid in systemic plasma where it has been shown to provide 22.6% (139.9 of 620.3 μg/mL) of the total in birds offered 215 g/kg CP, wheat-based diets. In addition to dietary intakes, glutamine biosynthesis is derived mainly from the condensation of glutamate and ammonia (NH₃) catalysed by glutamine synthetase, a reaction that is pivotal to NH₃ detoxification. Glutamate and NH₃ are converted to glutamine by phosphate-dependent glutaminase in the reciprocal reaction; thus, glutamine and glutamate are interchangeable amino acids. However, the rate of glutamine biosynthesis may not be adequate in rapidly growing broiler chickens and exogenous and endogenous glutamine levels are probably insufficient in birds offered reduced-CP diets. The many functional roles of glutamine, including NH₃ detoxification and maintenance of acid-base homeostasis, then become relevant. Twenty feeding studies were identified where dietary glutamine supplementation, usually 10 g/kg, was evaluated in birds kept under thermoneutral conditions. On balance, the outcomes were positive, but the average dietary CP was 213 g/kg across the twenty feeding studies, which indicates that CP and, in turn, glutamine concentrations would have been adequate. This suggests that glutamine inclusions in reduced-CP diets hold potential and consideration is given to how this may be best confirmed.

Dietary fat content can reduce the methane production of dairy cows; however, the relevance fatty acid (FA) composition has towards this inhibitory effect is debatable. Furthermore, in-depth studies elucidating the effects of unsaturated fatty acids (UFA) on rumen function and the mechanism of reducing methane (CH₄) production are lacking. This study exposed 10 Holstein cows with the same parity, similar milk yield to two total mixed rations: low unsaturated FA (LUFA) and high unsaturated FA (HUFA) with similar fat content. The LUFA group mainly added fat powder (C16:0 > 90%), and the HUFA group mainly replaced fat powder with extruded flaxseed. The experiment lasted 26 d, the last 5 d of which, gas exchange in respiratory chambers was conducted to measure gas emissions. We found that an increase in the UFA in diet did not affect milk production (P > 0.05) and could align the profile of milk FAs more closely with modern human nutritional requirements. Furthermore, we found that increasing the UFA content in the diet lead to a decrease in the abundance of Methanobrevibacter in the rumen (|linear discriminant analysis [LDA] score| > 2 and P < 0.05), which resulted in a decrease in the relative abundance of multiple enzymes (EC:1.2.7.12, EC:2.3.1.101, EC:3.5.4.27, EC:1.5.98.1, EC:1.5.98.2, EC:6.2.1.1, EC:2.1.1.86 and EC:2.8.4.1) during methanogenesis (P < 0.05). Compared with the LUFA group, the pathway of CH₄ metabolism was inhibited in the HUFA group (|LDA| > 2 and P < 0.05), which ultimately decreased CH₄ production (P < 0.05). Our results illustrated the mechanism involving decreased CH₄ production when fed a UFA diet in dairy cows. We believe that our study provides new evidence to explore CH₄ emission reduction measures for dairy cows.

This study investigated the impact of different ratios of soluble to insoluble dietary fiber (SDF:IDF) formulations by sugar beet pulp (SBP) supplementation on piglet growth performance, nutrient digestibility, immune function, intestinal morphology, intestinal microbiota and intestinal health. A total of 60 crossbred piglets (Duroc × [Landrace × Yorkshire]) at 40 d old with body weight of 10.0 ± 0.3 kg were randomly assigned to 5 treatments with 6 replicates per treatment and 2 piglets per replicate in a 21-d trial. The dietary treatments included a corn-soybean meal diet (0% SBP supplementation; CON), and diets supplemented with 2%, 4%, 6%, and 8% SBP, representing different SDF:IDF ratios at 10.16%, 13.53%, 16.79%, 19.86%, and 24.81%, respectively. The results indicated that the 8% SBP treatment had a negative effect on feed-to-gain ratio (linear, P = 0.009) compared with the CON treatment (P = 0.021). The apparent total tract digestibility (ATTD) of crude protein was lower in treatments supplemented with SBP (P = 0.002) and showed a linear decrease (P = 0.001), while the ATTD of IDF showed a linear increase (P = 0.037) in four SBP treatments compared to the CON treatment. The 4% SBP treatment increased serum concentrations of triglyceride (quadratic, P = 0.019) and K (linear, P = 0.037), and decreased alanine transaminase concentration (quadratic, P = 0.015) compared with the CON treatment. The concentrations of Cit, Cys, Ile, Leu, Orn, Arg, taurine, urea, 1-methylhistidine, α-aminoadipic acid, α-aminobutyric acid and cystathionine in the 4% SBP treatment were highest among all treatments (P < 0.05). The serum concentrations of interleukin-6, interleukin-8, interleukin-10, transforming growth factor-β, and tumor necrosis factor-α in the 6% SBP treatment were higher than those in the CON treatment (P < 0.05), which also increased mucin-2 and G protein-coupled receptor 41 mRNA expression (P < 0.05) in colonic mucosa compared with the CON treatment and improved the intestinal barrier function. Diets containing more than 19.86% SDF:IDF could impair the intestinal health in piglets when SBP was used as the SDF source. Supplementing nursery piglet diets with 16.79% to 19.86% SDF:IDF is recommended for improving intestinal barrier function, increasing short-chain fatty acids concentrations, and improving intestinal microbiota composition.

The development of skeletal muscle is a crucial factor in determining the meat yield and economic benefits of broiler production. Recent research has shown that mulberry leaves and their extracts can be used to significantly improve the growth performance of livestock and poultry. The present study aims to elucidate the mechanisms involved in the regulation of skeletal muscle development in broiler offspring by dietary mulberry-leaf flavonoids (MLF) supplementation from the perspective of maternal effect theory. A total of 270 Qiling broiler breeder hens were randomly assigned to 3 treatments with different doses of MLF (0, 30, 60 mg/kg) for 8 weeks before collecting their fertilized eggs. The chicken offspring at 13 and 19 d of embryonic stage, and from 1 to 28 d old after hatching were included in this study. The results showed that maternal supplementation increased the breast muscle weight and body weight of the offspring at the embryo and chick stages (P < 0.05). This was followed by increased cross-sectional area of pectoral muscle fibres at 14 d (P < 0.05). Further determination revealed a tendency towards increased serum levels of insulin-like growth factor 1 (IGF-1) (P = 0.092) and muscle fibre count (P = 0.167) at 1 d post-hatching following maternal MLF treatment, while serum uric acid (UA) was decreased at 14 d after hatching (P < 0.05). Moreover, maternal MLF supplementation significantly up-regulated the mRNA expression of the myogenic regulatory factor Myf5 in skeletal muscle at the both embryonic and growth stages (P < 0.05). The relative abundance of the downstream protein of BMPR2, Smad1 and p-Smad1/5/9 in the TGFβ signalling pathway was significantly increased by maternal MLF treatment. Meanwhile, the increased expression of the target protein p-mTOR in the breast muscle of the offspring chicks is in accordance with the improved growth rate of the breast and the body. In conclusion, maternal MLF supplementation can promote muscle protein metabolism and muscle fibre development of chick embryos through upregulation of Myf5 expression and BMP/p-Smad1/5/9 axis, thereby improving growth performance of slow growing broiler.

The aim of this study was to investigate the reasons for the differences in lipid accumulation between lean and obese pigs. The bile acids with varying levels within two types of pigs were found and then in vitro experiments were conducted to identify whether these bile acids can directly affect lipid accumulation. Fourteen pigs, including seven lean and seven obese pigs with body weights of approximately 80 kg, were fed the same diet at an amount approximately equivalent to 3% of their respective body weights daily for 42 d. In vitro, 3T3-L1 preadipocytes were cultured in medium with high glucose levels and were differentiated into mature adipocytes using differentiation medium. Then, bile acids were added to mature adipocytes for 4 d. The results showed that there was a difference in body lipids levels and gut microbiota composition between obese and lean pigs (P < 0.05). According to the results of gut microbial function prediction, the bile acid biosynthesis in colonic digesta of obese pigs were different from that in lean pig. Sixty-five bile acids were further screened by metabolomics, of which 4 were upregulated (P < 0.05) and 2 were downregulated (P < 0.05) in obese pigs compared to lean pigs. The results of the correlation analysis demonstrated that chenodeoxycholic acid-3-β-D-glucuronide (CDCA-3Gln) and ω-muricholic acid (ω-MCA) had a negative correlation with abdominal fat weight and abdominal fat rate, while isoallolithocholic acid (IALCA) was positively associated with crude fat in the liver and abdominal fat rate. There was a positive correlation between loin muscle area and CDCA-3Gln and ω-MCA (P < 0.05), however, IALCA and 3-oxodeoxycholic acid (3-oxo-DCA) were negatively associated with loin eye muscle area (P < 0.05). Isoallolithocholic acid increased the gene expression of peroxisome proliferator-activated receptor gamma (PPARG) and the number of lipid droplets (P < 0.05), promoting the lipid storage when IALCA was added to 3T3-L1 mature adipocytes in vitro. In conclusion, the concentration of bile acids, especially gut microbiota related-secondary bile acids, in obese pigs was different from that in lean pigs, which may contribute to lipid accumulation within obese pigs.

This study aims to elucidate the mechanism of lipid metabolism disorder in intrauterine growth retardation (IUGR) pigs and the potential alleviating effects of dimethylglycine sodium salt (DMG-Na). A total of 60 male newborn piglets were selected for this study. Within each litter, one normal birth weight (NBW) male piglet (1.53 ± 0.04 kg) and two IUGR male piglets (0.76 ± 0.06 kg) were chosen based on their birth weight. The piglets were divided into three groups for the study: NBW pigs received a PBS gavage and a common basal diet (NBW-C group), IUGR pigs received the same PBS gavage and common basal diet (IUGR-C group), and IUGR pigs received a 70-mg DMG-Na gavage along with a common basal diet supplemented with 0.1% DMG-Na (IUGR-D group). At 150 d of age, all piglets underwent euthanasia by exsanguination following electrical stunning, after which plasma, liver, and longissimus dorsi (LM) samples were promptly collected. The IUGR-D group demonstrated improvements in plasma parameters (P < 0.05), with lower triglyceride and free fatty acid (FFA) values, and hormone levels (P < 0.05), with lower growth hormone, insulin, and homeostasis model assessment of insulin resistance values. Restoration of lipid metabolism was observed (P < 0.05), with lower triglyceride and FFA, and higher hepatic lipase and total lipase values in the liver, and lower triglyceride and FFA values in the LM. Mitochondrial ETC complexes showed increased levels (P < 0.05), including higher complex III values in the liver, and higher complex I, complex III, and complex V values in the LM. Enhanced levels of energy metabolites were noted (P < 0.05), with higher NAD⁺, NAD⁺/NADH, adenosine triphosphate, and mtDNA values, and lower NADH values in the liver and LM. Additionally, meat quality parameters showed improvement (P < 0.05), with higher pH 24 h and a* values, and lower drip loss 48 h, L*, and b* values. The expressions of lipid metabolism and mitochondrial function-related genes and proteins were upregulated (P < 0.05) compared to the IUGR-C group. In conclusion, it was indicated that IUGR pigs experienced lipid metabolism disorders and diminished performance. However, supplementation with DMG-Na showed promise in mitigating these adverse physiological effects by safeguarding body tissues and modulating energy metabolism.

The transition period for dairy cows usually refers to the 3 weeks pre-calving to the 3 weeks post-calving. During this period, dairy cows undergo metabolic and physiological adaptations because of their susceptibility to metabolic and infectious diseases. Poor feeding management under these circumstances may adversely affect the health and subsequent production performance of the cows. Owing to long-term adaptation and evolution, the rumen has become a unique ecosystem inhabited by a complex microbial community closely associated with its natural host. Dietary components are metabolized by the rumen microbiota, and volatile fatty acids and microbial protein products can be used as precursor substances for synthesizing meat and milk components. The successful transition of perinatal dairy cows includes changes in diet, physiology, and the rumen microbiota. Rumen microbial profiles have been confirmed to be heritable and repairable; however, adverse circumstances affect rumen microbial composition, host digestion and metabolism, as well as postpartum production traits of dairy cows for a certain period. Preliminary evidence indicates a close relationship between the rumen microbiota and animal performance. Therefore, changes in rumen microbes during the transition period and the intrinsic links between the microbiota and host postpartum phenotypic traits need to be better understood to optimize production performance in ruminants.

Considerable research has been conducted into the efficacy of individual probiotics in broiler production, however information on the most effective combinations of synergistic Bacillus probiotic is lacking. This study investigated the impact of different Bacillus strain combinations in broiler chickens, as well as in vitro enzyme production. In experiment one, a total of 576 Ross 308 broilers at 1 d old were grown for 21 d across 6 treatments of maize-soybean diets (n = 12 pens per treatment) to compare three different strain combinations (formulation 1 [F1]: 3 strains Bacillus amyloliquefaciens; F2: Bacillus coagulans and 2 strains B. amyloliquefaciens; F3: B. coagulans, Bacillus licheniformis and 2 strains B. amyloliquefaciens; F5: Bacillus subtilis, B. licheniformis and 2 strains B. amyloliquefaciens), positive control (PC), and a negative control antibiotic treatment group (NC). In Exp. 2, a total of 360 one-day-old ROSS308 broilers were used to test five treatments (n = 9) including PC, NC, F1 and F5 (selected from Exp. 1), and F4 (Bacillus pumilis and 2 strains B. amyloliquefaciens) in a maize-soybean diet. B. amyloliquefaciens F1 demonstrated a significant improvement in feed conversion ratio (FCR) compared to F2 at d 14 (1.49 vs 2.10; P = 0.038) and the body weight (BW) at d 21 (847.0 g vs 787.4 g) compared to other combinations (P = 0.027). The FCR at d 21 tended to be lower in birds fed F1 (1.46 vs 1.66) compared to the control (P = 0.068). Probiotic treatments had significantly improved nutrient digestibility compared to the PC and NC. Also, probiotic treatments supported the growth of Streptococcus, a common commensal genus and reduced the abundance of genera that correlated with low weight gain such as Akkermansia. Experiment two revealed that F4 improved FCR (P < 0.001) and BW at 28 d (P = 0.014). In vitro testing showed a high production of protease and amylase by Bacillus. Thus, the addition of Bacillus probiotics, particularly containing B. amyloliquefaciens strains and Bacillus pumilus, into the diet of broiler chickens improves production performance, nutrient digestibility, and allows the proliferation of beneficial gut microbiota.

The intracellular lipids in muscle cells of farm animals play a crucial role in determining the overall intramuscular fat (IMF) content, which has a positive impact on meat quality. However, the mechanisms underlying the deposition of lipids in muscle cells of farm animals are not yet fully understood. The purpose of this study was to determine the roles of carbohydrate-response element binding protein (ChREBP) and fructose in IMF deposition of chickens. For virus-mediated ChREBP overexpression in tibialis anterior (TA) muscle of chickens, seven 5-d-old male yellow-feather chickens were used. At 10 d after virus injection, the chickens were slaughtered to obtain TA muscles for analysis. For fructose administration trial, sixty 9-wk-old male yellow-feather chickens were randomly divided into 2 groups, with 6 replicates per group and 5 chickens per replicate. The chickens were fed either a basal diet or a basal diet supplemented with 10% fructose (purity ≥ 99%). At 4 wk later, the chickens were slaughtered, and breast and thigh muscles were collected for analysis. The results showed that the skeletal ChREBP mRNA levels were positively associated with IMF content in multiple species, including the chickens, pigs, and mice (P < 0.05). ChREBP overexpression increased lipid accumulation in both muscle cells in vitro and the TA muscles of mice and chickens in vivo (P < 0.05), by activation of the de novo lipogenesis (DNL) pathway. Moreover, activation of ChREBP by dietary fructose administration also resulted in increased IMF content in mice and notably chickens (P < 0.05). Furthermore, the lipidomics analysis revealed that ChREBP activation altered the lipid composition of chicken IMF and tented to improve the flavor profile of the meat. In conclusion, this study found that ChREBP plays a pivotal role in mediating the deposition of fat in chicken muscles in response to fructose-rich diets, which provides a novel strategy for improving meat quality in the livestock industry.