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.

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.

A comprehensive understanding of the role of dietary fibre in non-ruminant animal production is elusive. Equivocal and conflated definitions of fibre coupled with significant analytical complexity, interact with poorly defined host and microbiome relationships. Dietary fibre is known to influence gut development, feed intake and passage rate, nutrient absorption, microbiome taxonomy and function, gut pH, endogenous nutrient loss, environmental sustainability, animal welfare and more. Whilst significant gaps persist in our understanding of fibre in non-ruminant animal production, there is substantial interest in optimizing the fibre fraction of feed to induce high value phenotypes such as improved welfare, live performance and to reduce the environmental footprint of animal production systems. In order to achieve these aspirational goals, it is important to tackle dietary fibre with the same level of scrutiny as is currently done for other critical nutrient classes such as protein, minerals and vitamins. The chemical, mechanical and nutritional role of fibre must be explored at the level of monomeric sugars, oligosac-charides and polysaccharides of varying molecular weight and decoration, and this must be in parallel to standardisation of analytical tools and definitions for speciation. To further complicate subject, exogenous carbohydrases recognise dietary fibre as a focal substrate and have varying capacity to generate lower molecular weight carbohydrates that interact differentially with the host and the enteric microbiome. This short review article will explore the interactive space between dietary fibre and exogenous carbohydrases and will include their nutritional and health effects with emphasis on functional development of the gut, microbiome modulation and host metabolism.

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.

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.

This study was to conducted to investigate the effect of red clover isoflavones on the health indicated by immune status and blood biochemistry in dairy cows. Sixty-eight healthy Holstein lactating cows were randomly divided into four treatments (n = 17 per treatment) from 5 blocks according to milk yield using a randomized complete block design. No initial differences in parity (2.13 ± 1.21), days in milk (165 ± 21 d), and milk yield (33.93 ± 3.81 kg/d) between groups. Cows were fed the basal diet supplemented with 0, 2, 4, or 8 g/kg red clover extract (RCE) in diet (dry matter based). Feeding, refusal feed weights, and milk yield were recorded three consecutive days in weeks 0, 4, 8, and 12. Blood was collected from the tail vein of the cows on the last day of weeks 4, 8 and 12, 1 h after the morning feeding, and analyzed for hormones, immunoglobulins, inflammatory markers, and markers of liver and kidney activities. The dry matter intake was significantly decreased by 3.7% in the 8 g/kg group (P < 0.05). The fat-corrected milk yield was significantly higher in both of the 2 and 4 g/kg groups (P < 0.01). Plasma estradiol and prolactin showed a quadratic effect with increasing RCE levels, with the highest in the 4 g/kg group (P < 0.05). Plasma tumor necrosis factor (TNF)-α, interleukin (IL)-6, and IL-1β levels decreased linearly with increasing dietary RCE levels. Plasma IL-18 levels showed a quadratic effect with increasing dietary RCE levels, with significantly lower levels in both of the 2 and 4 g/kg groups (P < 0.05). Plasma immunoglobulin A and D-lactic acid levels showed a quadratic effect with increasing dietary RCE levels, with significantly higher level in the 4 g/kg group (P < 0.05). The liver function and kidney activity makers were similar (P > 0.05). These results recommend the supplementation of RCE at a level from 2 to 4 g/kg DM.

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.

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.

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.

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.