This study was conducted to evaluate the effects of Monascus purpureus M-32 fermented soybean meal (MFSM) on growth, immunity, intestinal morphology, intestinal microbiota, and intestinal metabolome of Pacific white shrimp (Litopenaeus vannamei). Four groups of diets were formulated, including control group (30% fish meal and 30% soybean meal [SBM] included in the basal diet) and three experimental groups which MFSM replaced 20% (MFSM20), 40% (MFSM40), and 60% (MFSM60) of SBM in control group, respectively. Results showed that the soluble proteins larger than 49 kDa in MFSM were almost completely degraded. Meanwhile, the crude protein, acid-soluble protein, and amino acid in MFSM were increased. The results of shrimp culture experiment showed that the replacement of SBM with MFSM decreased FCR (P < 0.001) and content of malondialdehyde (P = 0.007) in the experimental groups, and increased weight gain rate (P = 0.006), specific growth rate (P = 0.002), survival rate (P = 0.005), intestinal villus height (P < 0.001), myenteric thickness (P = 0.002), the activities of superoxide dismutase (P = 0.002), and lysozyme (P = 0.006) in experimental groups, as well as increased content of calcium (Ca²⁺) and phosphorus () in blood and muscle, and enhanced resistance to Vibrio parahaemolyticus infection. The gut microbiota of MFSM groups was significantly different from that of the control group, and the abundance of Actinobacteria and Verrucomicrobia increased significantly in the MFSM60 group, whereas Proteobacteria and Firmicutes decreased. Compared with the control group, there were significant changes in the levels of several intestinal metabolites in the MFSM60 group, including leukotriene C5, prostaglandin A1, taurochenodeoxycholic acid, carnosine, and itaconic acid. The fermentation of SBM by the strain M. purpureus M-32 has the potential to enhance the nutritional quality of SBM, promote the growth of L. vannamei, boost immune response, improve intestinal morphology and microbiota composition, as well as influence intestinal metabolites.

Fat content is an important trait in pig production. Adipose tissue and muscle are important sites for fat deposition and affect production efficiency and quality. To regulate the fat content in these tissues, we need to understand the mechanisms behind fat deposition. Laiwu pigs, a Chinese indigenous breed, have significantly higher fat content in both adipose tissue and muscle than commercial breeds such as Duroc. In this study, we analyzed the transcriptomes in adipose tissue and muscle of 21-d-old Laiwu and Duroc piglets. Results showed that there were 828 and 671 differentially expressed genes (DEG) in subcutaneous adipose tissue (SAT) and visceral adipose tissue (VAT), respectively. Functional enrichment analysis showed that these DEG were enriched in metabolic pathways, especially carbohydrate and lipid metabolism. Additionally, in the longissimus muscle (LM) and psoas muscle (PM), 312 and 335 DEG were identified, demonstrating enrichment in the cell cycle and metabolic pathways. The protein–protein interaction (PPI) networks of these DEG were analyzed and potential hub genes were identified, such as FBP1 and SCD in adipose tissues and RRM2 and GADL1 in muscles. Meanwhile, results showed that there were common DEG between adipose tissue and muscle, such as LDHB, THRSP, and DGAT2. These findings showed that there are significant differences in the transcriptomes of the adipose tissue and muscle between Laiwu and Duroc piglets (P < 0.05), especially in metabolic patterns. This insight serves to advance our comprehensive understanding of metabolic regulation in these tissues and provide targets for fat content regulation.

Diet is a major modulator of animal resilience and its three pillars: host's immune response, gut microbiota, and intestinal barrier. In the present study, we endeavour to delineate a challenging condition aimed to degrade these pillars and elucidate its impact on broiler performance and nutrient digestibility. To attain this objective, we opted to use guar gum (GG) as a source of galactomannan. A series of three in vivo experiments were conducted employing conventional or semi-purified diets, supplemented with or without GG during the grower phase (14–28 d). Our findings demonstrate a substantial decline in animal performance metrics such as body weight (reduced by 29%, P < 0.001), feed intake (decreased by 12%, P < 0.001), and feed conversion ratio (up to 58% increase, P < 0.001) in the presence of GG at 2%. The supplementation of a semi-purified diet with incremental doses of GG resulted in a linear reduction (P < 0.001) in the apparent total tract digestibility of dry matter and apparent metabolisable energy. Additionally, a marked reduction in ileal endogenous losses, as well as apparent and standardised digestibility of all amino acids with varying proportions (P < 0.05), was observed. These alterations were accompanied by disrupted gut integrity assessed by fluorescein isothiocyanate-dextran (FITC-d) (P < 0.001) as well as an inflammatory status characterised by elevated levels of acute-phase proteins, namely orosomucoid and serum amyloid A in the sera (P = 0.03), and increased mRNA expression levels of IL-1, IL-6, IL-8, Inos, and K203 genes in the ileum, along with a decrease in IgA levels in the gut lumen (P < 0.05). Microbial ecology and activity were characterised by reduced diversity and richness (Shannon index, P = 0.005) in the presence of GG. Consequently, our results revealed diminished levels of short-chain fatty acids (P = 0.01) and their producer genera, such as Clostridium_XIVa and Blautia, in the gut caeca, coupled with excessive accumulation of lactate (17-fold increase, P < 0.01) in the presence of GG at 2%. In addition to providing a more comprehensive characterisation of the GG supplementation as a leaky gut model, our results substantiate a thorough understanding of the intricate adjustments and interplay between the intestinal barrier, immune response, and microbiota. Furthermore, they underscore the significance of feed components in modulating these dynamics.

In vitro model provides alternatives to the use of live animals in research. In pig nutrition, there has been a tremendous increase in in vivo research over the decades. Proper utilization of in vitro models could provide a screening tool to reduce the needs of in vivo studies, research duration, cost, and the use of animals and feeds. This study aimed to develop a multi-step porcine in vitro system to simulate nutrient digestion and intestinal epithelial immune responses affected by feedstuffs and feed additives. Seven feedstuffs (corn, corn distillers dried grains with solubles [corn DDGS], barley, wheat, soybean meal, soy protein concentrates, and Corynebacterium glutamicum cell mass [CGCM]), feed enzymes (xylanase and phytase), and supplemental amino acids (arginine, methionine, and tryptophan), were used in this in vitro evaluation for their efficacy on digestibility, digesta characteristics, and intestinal health compared with the results from previously published in vivo studies. All in vitro evaluations were triplicated. Data were analyzed using Mixed procedure of SAS9.4. Evaluations included (1) nutrient digestibility of feedstuffs, (2) the effects of feed enzymes, xylanase and phytase, on digestibility of feedstuffs and specific substrates, and (3) the effects of amino acids, arginine, tryptophan, and methionine, on anti-inflammatory, anti-oxidative, and anti-heat stress statuses showing their effects (P < 0.05) on the measured items. Differences in dry matter and crude protein digestibility among the feedstuffs as well as effects of xylanase and phytase were detected (P < 0.05), including xylo-oligosaccharide profiles and phosphorus release from phytate. Supplementation of arginine, tryptophan, and methionine modulated (P < 0.05) cellular inflammatory and oxidative stress responses. The use of this in vitro model allowed the use of 3 experimental replications providing sufficient statistical power at P < 0.05. This indicates in vitro models can have increased precision and consistency compared with in vivo animal studies.

The prevalent practice of substituting fishmeal with plant protein frequently leads to disturbances in bile acid metabolism, subsequently increasing the incidence of metabolic liver diseases. Bile acid nutrients such as cholesterol, taurine and glycine have been shown to enhance bile acid synthesis and confer beneficial effects on growth. Therefore, this study aimed to investigate the effects of cholesterol-taurine-glycine (Ch-Tau-Gly) supplement on bile acid metabolism and liver health in spotted seabass (Lateolabrax maculatus) fed a plant-based diet. Two isonitrogenous and isolipidic diets were formulated: (1) plant protein-based diet (PP); (2) PP supplemented 0.5% cholesterol, 0.5% taurine and 1.3% glycine (CTG). Each experimental diet was randomly fed to quadruplicate groups of 30 feed-trained spotted seabass in each tank. The results revealed that supplementing plant-based diet with Ch-Tau-Gly supplement led to an increase in carcass ratio (meat yield) in spotted seabass (P < 0.05), indirectly contributing positively to their growth. The dietary supplement effectively suppressed endogenous cholesterol synthesis in the liver, promoted the expression of bile acid synthesis enzyme synthesis, and simultaneously the expression of intestinal fxr and its downstream genes, including hnf4α and shp (P < 0.05). The reduction in Lactobacillus_salivarius and bile salt hydrolase (BSH) were observed in CTG group with concurrently increased conjugated chenodeoxycholic acid (CDCA) bile acids (P < 0.05), suggesting the enhancement of the hydrophilicity of the bile acid pool. In CTG group, fatty liver was alleviated with a corresponding increase in lipid metabolism, characterized by a downregulation of genes associated with lipogenesis and lipid droplet deposition, along with an upregulation of genes related to lipolysis. Our study underscored the ability of Ch-Tau-Gly supplement to influence the gut microbiota, leading to an increase in the levels of conjugated CDCA (P < 0.05) in the bile acid pool of spotted seabass. The interplay between the gut microbiota and bile acids might constitute a crucial pathway in the promotion of liver health. These findings offer a promising solution, suggesting that Ch-Tau-Gly supplement have the potential to promote the growth of aquatic species and livestock fed on plant-based diets while addressing issues related to metabolic fatty liver.

Hermetia illucens (HI) meal is a promising substitute for fish meal (FM) in the feeds of farmed fish. However, the impacts of dietary HI meal on largemouth bass (LMB) remain unknown. In this study, we formulated three isonitrogenous and isolipid diets with 0% (HI0, control), 20% (HI20) and 40% (HI40) of FM substituted by HI meal. A total of 270 juvenile largemouth bass with an initial body weight of 10.02 ± 0.03 g were used (30 fish per tank). After an 80-day feeding trial, the fish fed with the HI40 diet demonstrated decreased growth performance and protein efficiency ratio (PER), and increased liver oxidative indices and lipid accumulation compared to the control (P < 0.05). Transcriptomic analysis revealed the effects of high dietary HI meal on liver gene expression. Consistent with the reduced growth and disturbed liver oxidative status, the upregulated genes were enriched in the biological processes associated with protein catabolism and endoplasmic reticulum (ER) stress; while the downregulated genes were enriched in cellular proliferation, growth, metabolism, immunity and maintenance of tissue homeostasis. Differential metabolites in the liver samples were also identified by untargeted metabolomic assay. The results of joint transcriptomic–metabolomic analyses revealed that the pathways such as one carbon pool by folate, propanoate metabolism and alpha-linolenic acid metabolism were disturbed by high dietary HI meal. In summary, our data revealed the candidate genes, metabolites and biological pathways that account for the adverse effects of high HI meal diet on the growth and health of LMB.

Previous studies have shown that maternal resveratrol improved growth performance and altered the microbial composition of suckling piglets under hot summer conditions. However, it remains unclear how maternal resveratrol improves growth performance of suckling piglets during high summer temperatures. A total of 20 sows (Landrace × Large White; three parity) were randomly assigned to 2 groups (with or without 300 mg/kg resveratrol) from d 75 of gestation to d 21 of lactation during high ambient temperatures (from 27 to 30 °C). The results showed that maternal resveratrol supplementation increased total daily weight gain of piglets under hot summer conditions, which is consistent with previous studies. Furthermore, we found that maternal resveratrol improved the intestinal morphology and intestinal epithelial proliferation in suckling piglets. Dietary resveratrol supplementation affected the characteristics of exosome-derived microRNAs (miRNAs) in sow colostrum, as well as the genes targeted by differentially produced miRNAs. MiRNAs are concentrated in the tight junction pathway. As a result, the expression of intestinal tight junction proteins was increased in suckling piglets (P < 0.05). Notably, maternal resveratrol increased the intestinal secretory immunoglobulin A (sIgA) levels of suckling piglets via colostrum immunoglobin (P < 0.05), which could increase the abundance of beneficial microbiota to further increase the concentration of short chain fatty acids (SCFA) in suckling piglets' intestine (P < 0.05). Finally, our correlation analysis further demonstrated the positive associations between significantly differential intestinal microbiota, intestinal sIgA production and SCFA concentrations, as well as the positive relation between total daily weight gain and intestinal health of suckling piglets. Taken together, our findings suggested that maternal resveratrol could promote intestinal health to improve piglet growth during high summer temperatures, which might be associated with the immunoglobin and exosome-derived miRNAs in sows' colostrum.

In recent decades, a lot of research has been conducted to explore poultry feeding behavior. However, up to now, the processes behind poultry feeding behavior remain poorly understood. The review generalizes modern expertise about the hormonal regulation of feeding behavior in chickens, focusing on signaling pathways mediated by insulin, leptin, and ghrelin and regulatory pathways with a cross-reference to mammals. This overview also summarizes state-of-the-art research devoted to hypothalamic neuropeptides that control feed intake and are prime candidates for predictors of feeding efficiency. Comparative analysis of the signaling pathways that mediate the feed intake regulation allowed us to conclude that there are major differences in the processes by which hormones influence specific neuropeptides and their contrasting roles in feed intake control between two vertebrate clades.

Trimethylamine oxide (TMAO) is a microbiota-derived metabolite, and numerous studies have shown that it could regulate fat metabolism in humans and mice. However, few studies have focused on the effects of TMAO on fat deposition in growing-finishing pigs. This study aimed to investigate the effect of TMAO on fat deposition and intestinal microbiota in growing-finishing pigs. Sixteen growing pigs were randomly divided into 2 groups and fed with a basal diet with 0 or 1 g/kg TMAO for 149 d. The intestinal microbial profiles, fat deposition indexes, and fatty acid profiles were measured. These results showed that TMAO supplementation had a tendency to decrease lean body mass (P < 0.10) and significantly increased backfat thickness (P < 0.05), but it did not affect growth performance. TMAO significantly increased total protein (TP) concentration, and reduced alkaline phosphatase (ALP) concentration in serum (P < 0.05). TMAO increased the α diversity of the ileal microbiota community (P < 0.05), and it did not affect the colonic microbial community. TMAO supplementation significantly increased acetate content in the ileum, and Proteobacteria and Escherichia–Shigella were significantly enriched in the TMAO group (P < 0.05). In addition, TMAO decreased fat content, as well as the ratio of linoleic acid, n-6 polyunsaturated fatty acids (PUFA), and PUFA in the liver (P < 0.05). On the contrary, TMAO increased intramuscular fat content of the longissimus dorsi muscle, whereas the C18:2n6c ratio was increased, and the n-6 PUFA:PUFA ratio was decreased (P < 0.05). In vitro, 1 mmol/L TMAO treatment significantly upregulated the expression of FASN and SREBP1 in C2C12 cells (P < 0.05). Nevertheless, TMAO also increased adipocyte area and decreased the CPT-1B expression in subcutaneous fat (P < 0.05). Taken together, TMAO supplementation regulated ileal microbial composition and acetate production, and regulated fat distribution and fatty acid composition in growing-finishing pigs. These results provide new insights for understanding the role of TMAO in humans and animals.

Nitrogen pollution resulting from excessive feed consumption poses a significant challenge for modern swine production. Precision nutrition technology seems to be an effective way to solve this problem; therefore, understanding the law of pig body composition deposition is a prerequisite. This study investigated the sex effects on growth performance, body composition, nutrient deposition, gut microbiota, and short-chain fatty acids (SCFA) in weaned piglets. Eighty weaned pigs were randomly allocated to 2 treatments according to the sex of pigs. An individual pig was considered as a treatment replicate. Six body weights (BW 5, 7, 11, 15, 20, and 25 kg) were chosen as experimental points; for each point 10 piglets close to the average BW (5 males and 5 females) were slaughtered, and there was one growth phase between each 2 BW points. Results indicated that the males had higher average daily gain (ADG) and average daily feed intake (ADFI) compared to the females (P < 0.05) at growth phases 15 to 20 kg BW and 20 to 25 kg BW. Meanwhile, males at 20 kg BW had higher body fat content than females (P < 0.10). Males showed a higher body fat (P < 0.05) deposition rate at phase 15 to 20 kg BW (P < 0.05) than females. For pigs at 20 kg BW, the relative abundance of Ruminococcaceae UCG-005, Clostridium, Christensenellaceae_R-7_group, and Peptostreptococcaceae was significantly increased in males (P < 0.05) but that of Bifidobacterium was decreased (P < 0.05). At 25 kg BW, the relative abundance of Ruminococcaceae_NK4A214_group, Fibrobacter, Ruminococcaceae UCG-009, Ralstonia, Klebsiel, and Christensenellaceae_R-7_group in males was higher when compared with females (P < 0.05). In terms of SCFA, females exhibited higher concentrations of propionate compared to males (P < 0.05). The results of the current study indicated that sex influenced fat deposition through changes in the composition of gut microbiota and the content of SCFA, which has significant implications for the realization of precision nutrition in modern swine production.