High lipid diets (HLD) and high plant-protein diets (HPD) exhibit potential fishmeal-saving effects but negatively impact liver health and growth performance in fish. We hypothesized that HLD and HPD impair liver health in pearl gentian groupers (Epinephelus fuscoguttatus♂ × Epinephelus lanceolatus♀) through the modulation of intestinal microbiota and bile acid (BA) metabolism. Four diet groups were tested: control diet (CD, 46.21% crude protein, 9.48% crude lipid), HLD (46.37% crude protein, 16.70% crude lipid), HPD (46.50% crude protein, 9.38% crude lipid), and high lipid-high plant-protein diet (HLPD, 46.54% crude protein, 16.67% crude lipid). A total of 300 fish (average body weight = 15.22 ± 0.03 g) were randomly divided into 4 diet treatments (ensuring 3 tanks replicates of each diet treatment, each tank containing 25 fish). After an eight-week feeding period, the HLD and HPD significantly decreased the final body weight (FBW), weight gain rate (WGR), specific growth rate (SGR) and feed intake (FI) in comparison to CD group, with HLPD exacerbating these indicators (P < 0.05). Compared to CD group, the content of total cholesterol (T-CHO) and triglyceride (TG) in liver and serum were significantly increased in HLD group (P < 0.05). Compared to HPD group, the content of T-CHO in liver was significantly decreased, the content of TG in liver and serum were significantly increased in HLPD group (P < 0.05). HLD, HPD, and HLPD impaired liver health by inducing histological damage, inflammation, and oxidative stress. Compared to CD group, the mRNA relative expression of bile salt export pump (bsep) and multidrug resistance protein 3 (mdr3) were significantly increased in HLD group, whereas the mRNA relative expression of sterol-27-hydroxylase (cyp27a1), microsomal epoxide hydrolase (meh), apical sodium-dependent bile acid transporter (asbt), multidrug resistance-associated protein 3 (mrp3), farnesoid X receptor (fxr) and G protein-coupled bile acid receptor 5 (tgr5) were significantly decreased (P < 0.05). Compared to CD group, the mRNA relative expression of mdr3, asbt, mrp3, organic anion transporters 1 (oatp1), meh, fxr and tgr5 were significantly decreased in HPD group (P < 0.05). In summary, HLD affects intestinal microbiota, BA metabolism, and lipid metabolism, leading to lipid deposition and liver damage. HPD regulates gut microbiota, BA metabolism, inflammatory responses, and BA receptor expression, impairing grouper liver health. HLPD synergistically combines the adverse effects of HLD and HPD on grouper liver health.

The aims of the present study were to investigate the effects of dietary supplementation with rumen-protected taurine (RPT) on the whole-body protein turnover, the plasma metabolomics, and the whole blood cell transcriptomics in steers. Eight steers, averaging 220 ± 3.26 kg of liveweight, were allocated in a replicate 4 × 4 Latin square design. The experimental treatments consisted of four levels of RPT supplementation: 0, 25, 50, and 75 g RPT per day, added to a basal diet. The results showed that supplementation with RPT linearly decreased the fecal nitrogen (N) excretion (P = 0.001) and the ¹⁵N fractional recovery rate (P = 0.047), while it linearly increased the urinary excretion of taurine (P = 0.045) as well as the average daily weight gain (P = 0.003), the protein synthesis (P < 0.001), the protein degradation (P < 0.001) and the whole-body protein turnover (P < 0.001). Supplementation with RPT linearly increased the plasma concentrations of growth hormone (P = 0.005) and quadratically affected the plasma concentration of insulin-like growth factor-1 (P = 0.013), and it linearly decreased the plasma concentration of albumin (P = 0.022). Supplementation with RPT altered the whole blood cell mRNA expression and upregulated the expressions of the marker genes, including RPS6KB1, PRSS42, COL1A2, ENSBTAG00000013055 and ENSBTAG00000038159 which are related to protein metabolism. The plasma metabolomics profiling indicated that supplementation with RPT upregulated the plasma concentrations of taurine, lysine and methionine. The experiment revealed the impact and the mechanisms of taurine on driving whole-body protein turnover and protein accretion in steers. Two novel marker genes which could be related to body protein degradation in steers were identified.

The milk replacer feeding regime in dairy calves has a great impact on metabolic and immunological functioning and affects animal welfare and lifetime performance. The feeding regime influences the rumen microbial composition, and epithelium-associated microbes may interact with the immune system of the host. We examined the correlations between blood leukocyte counts and the rumen epithelium-associated microbiome in dairy calves fed 2 different milk replacer feeding intensities and if these factors related to metabolic traits. Fourteen newborn female dairy calves were allocated to a group receiving either 10% (n = 7) or 20% (n = 7) milk replacer of their body weight (on average 41 kg) and provided ad libitum access to grass hay and concentrate pellets. At 3 weeks of life, all calves were fitted with a rumen cannula. Calves were weaned at 12 weeks of life and received a total mixed ration for ad libitum intake. Pre- (8–10 weeks of life) and post-weaning (21–23 weeks of life), methane production was measured in respiration chambers, and rumen epithelium and blood were sampled for 16S rRNA sequencing and leukocyte analyses, respectively. Pre-weaning, the reduced milk replacer feeding intensity was accompanied with higher concentrate intake but lower growth performance (P < 0.001), a higher abundance of amylolytic and lower abundance of cellulolytic epimural microbes. The group fed a low milk replacer intensity had also greater portions of monocytes (P = 0.031), CD8⁺ (P < 0.001), and CD14⁺ (P = 0.044) leukocytes, suggesting elevated inflammatory conditions. Correlations between CD8⁺ T cells and rumen methanogens, Ruminococcaceae, and Lachnospiraceae were recorded, but these were not consistent throughout maturation. Post-weaning, differences in feed intake and rumen microbial composition converged among milk replacer groups, while differences in growth performance (P = 0.040) and CD8⁺ cells (P < 0.001) were still present. In conclusion, a reduced milk replacer feeding intensity in dairy calves compromised growth performance and immunity and this effect persisted in the long-term. Significant correlations between the proportion of leukocytes and distinct epimural microbe taxa indicated an interplay between rumen epimural colonization and immune functioning of the host. However, further research is required addressing this interplay between rumen epimural microbes and immune functioning in dairy calves.

This study evaluated the effect of black soldier fly (Hermetia illucens) larvae oil (BO) produced by a novel technique, subcritical butane extraction, on the flesh quality, lipid nutrients and muscle growth of rainbow trout (Oncorhynchus mykiss) fillet, and investigated the alleviating mechanisms of dietary astaxanthin (AST) supplementation. Two hundred and forty fish (215.16 ± 2.30 g) were distributed to three groups with four replicates. Fish were fed three experimental diets for 8 weeks: the control diet (CD diet), total fish oil of the CD diet was replaced with BO to formulate the BO100 diet, and then 1 g/kg AST was supplemented with the BO100 diet to formulate the AST diet. Results showed that the final body weight and the sarcomere length of fillet were significantly increased and the protein phosphorylation levels of mammalian target of rapamycin (mTOR) and p70 S6 kinase were enhanced in the BO100 group compared to the CD group (P < 0.05). However, there was a reduction in the hardness, springiness and chewiness of fillets, with a decrease in eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) levels in the fish of the BO100 group (P < 0.05). Supplementation of AST in the BO100 diet mitigated the impairment of springiness and chewiness and further promoted the sarcomere length of fillet (P < 0.05). Furthermore, dietary AST partially restored the EPA and DHA content of fillet by increasing the phosphorylation levels of serine/threonine kinase (AKT) and AMP-activated protein kinase α (AMPKα) (P < 0.05) and activating the gene expression of unsaturated fatty acid synthesis. To conclude, BO produced by subcritical butane extraction can be a readily available oil source for rainbow trout feed that can be used to promote muscle growth in rainbow trout. Further dietary AST supplementation can alleviate BO-induced lipid accumulation, restore DHA levels and improve the flesh quality of rainbow trout fillet.

This study aimed to compare the effects of dietary methionine (Met) and 2-hydroxy-4-(methylthio)-butanoate (HMTBA) on the eggshell quality of broiler breeder hens and elucidate the mechanism of Met in improving eggshell quality from the perspectives of eggshell microstructure and shell gland physiological function. A total of 720 WOD188 broiler breeder hens at 40 weeks old were assigned to 3 groups, with 8 replicates per group and 30 birds per replicate. Over 7 weeks, birds were fed a basal diet or the same diet supplemented with 0.15% Met or 0.17% HMTBA. Our findings revealed significant improvements in the Met group for egg shape index, shell thickness, breaking strength, and fracture toughness (P < 0.05), whereas the HMTBA group showed no significant improvements (P > 0.05). Met supplementation increased calcium and phosphorus levels in both serum and shell gland tissue (P < 0.05), and enhanced Ca²⁺ ATPase activity in shell gland tissue (P < 0.05). Histomorphological changes cluded enhanced mucosal fold dimensions and increased epithelial height in the shell gland (P < 0.05). Met also improved eggshell ultrastructure, resulting in a thicker effective layer and broader mammillae with fewer type B structures (P < 0.05). The mRNA levels for genes regulating eggshell ultrastructure, such as ovocleidin-116 (OC-116), calbindin 1 (CALB1), and integral membrane protein 2C (ITM2C), were significantly upregulated in the Met group (P < 0.05). Transcriptome analysis identified 248 differentially upregulated genes in the Met group, primarily linked to the non-canonical Wnt/Ca²⁺ signaling pathway, crucial for calcium ion transport and cellular proliferation. This research highlights that Met supplementation improves eggshell quality by enhancing calcium transport and cellular proliferation in uterine function, particularly through the modulation of Wnt family member 11 (WNT11) and CALB1, influencing calcium deposition and ultrastructural development.

Diarrhea poses a significant threat to the health and well-being of weaned piglets, leading to substantial morbidity and mortality and economic loss in the pig industry. However, the structural characteristics of the gut microbiota and the key genera associated with early diarrhea in piglets within large-scale production systems are poorly understood. This study aimed to investigate the differences in the microbial community structure and the specific genera alteration between the healthy piglets and diarrhea piglets, and to identify the biomarkers of gut microbiota associated with diarrhea in piglets. A total of 250 fecal samples, including 130 healthy piglets (Duroc × Landrace × Large Yorkshire) in the Control group and 120 from diarrhea piglets in Diarrhea group, were collected from three large-scale farms as discovery cohorts and were used for 16S rRNA gene sequencing. Additionally, 150 fecal samples from another large-scale pig farm were collected for the validation trail. The Chao1 and ACE indices were obviously lower (P < 0.01) in the diarrhea piglets compared to the healthy ones. Principal coordinate analysis showed significant differences in the distance matrix of gut microbiota between the healthy and diarrhea piglets (Bray-Curtis: P = 0.001, Jaccard: P = 0.001). Eighty-five genera were differentially enriched (P < 0.001) between healthy and diarrhea piglets. Notably, Treponema, Sphaerochaeta, Escherichia-Shigella, Slackia, and Staphylococcus were identified as potential biomarkers of diarrhea susceptibility; Clostridium sensu stricto 1, Prevotella_9, Olsenella, Dorea, and Lachnospiraceae NK4A136 group were found to be beneficial for maintaining intestinal homeostasis. These differentially enriched genera of healthy and diarrhea piglets were further confirmed in the validation cohort. In conclusion, this study identified the diarrhea-associated and beneficial genera in the faces of piglet, providing a theoretical basis for the diagnosis and intervention of diarrhea in weaned piglets.

Intramuscular fat (IMF) content influences various meat quality traits, including tenderness, flavor, juiciness and nutritional value. This study aimed to investigate the effects of dietary inositol supplementation on meat quality, metabolic profiles, and gut microbiota composition of finishing pigs. A total of 144 finishing pigs (initial body weight 70.41 ± 0.78 kg) were randomly divided into control, 0.075%, 0.15%, and 0.3% inositol groups. The data showed that inositol increased backfat thickness at the 6th to 7th rib and 10th rib, IMF content, and improved tenderness (P ≤ 0.05, n = 8). Paralleling an increase in fat deposition, 0.3% inositol also increased the protein level of PPARγ in the subcutaneous fat (P ≤ 0.05) and longissimus thoracis (LT) muscle (P = 0.062). Inositol elevated the content of amino acids in LT muscle and enhanced amino acid metabolism of finishing pigs, including lysine degradation, tyrosine metabolism, and arginine and proline metabolism. The 16S ribosomal RNA (rRNA) sequencing showed that 0.3% inositol supplementation altered the profiles of microbes in the colon, particularly decreasing the abundance of Firmicutes (P < 0.01) and increasing the abundance of Bacteroidota (P ≤ 0.05). Correlation analysis showed that differential microbes had strong correlation with differential metabolites in serum, including amino acids. In conclusion, this study demonstrated that dietary inositol supplementation could effectively improve IMF content and tenderness of pork, enhance amino acid metabolism, and regulate gut microbiota composition of finishing pigs.

The study evaluated the effects of nutritional strategies on broilers challenged with Eimeria from d 14 to 26. A total of 840 Cobb male broilers were fed five diets in a 2 × 5 factorial arrangement: 1) nutrient adequate diet (PC; 0.84% calcium [Ca], 0.42% available phosphorus [avP]); 2) Ca-P deficient diet (NC; 0.64% Ca, 0.22% avP); 3) NC + 1500 FTU/kg phytase of diet (NC + PHY); 4) NC + 5000 IU/kg 25-hydroxycholecalciferol of diet (NC + 25OHD); and 5) NC with both supplements (NC + PHY + 25OHD), with and without Eimeria challenge. All treatments had six replicate cages with 14 birds per cage. At 5 days post inoculation (DPI), the challenged birds exhibited higher serum fluorescein isothiocyanate-d (FITC-d) levels than the unchallenged birds (P < 0.001). The NC + PHY and NC + PHY + 25OHD groups exhibited lower FITC-d levels compared to the NC + 25OHD group (P = 0.012). Significant interaction effects between Eimeria challenge and dietary treatments were observed on various parameters. During 0 to 6 and 0 to 12 DPI, Eimeria challenge resulted in decreased the body weight gain (BWG) (P < 0.05) but had a negative effect on the feed conversion ratio (FCR) in birds compared to the unchallenged group (P < 0.05). Reducing Ca and avP levels in the diet (NC) did not adversely affect BWG, but negatively impacted FCR, bone ash weight, ash concentration, and femur bone microstructure parameters (P < 0.05). On 12 DPI, Eimeria challenge led to decreased tibia bone weight, bone volume, fat-free bone weight (FFBW), and ash weight of birds (P < 0.05). Supplementation with phytase alone or in combination with 25OHD improved growth performance, gut permeability, bone ash and bone microstructure parameters in birds (P < 0.05). However, the group fed 25OHD alone showed enhancements on growth performance, mineral apposition rate (MAR), bone ash concentration and ash percentage of the birds (P < 0.05). In conclusion, lowering Ca and avP levels in the diet negatively affected FCR and bone development but did not affect intestinal integrity in broilers. Dietary supplementation of phytase, 25OHD, or phytase in combination of 25OHD could enhance the growth performance and bone quality of broilers infected with Eimeria. Notably, the benefits of phytase supplementation were generally more pronounced than those associated with 25OHD supplementation; however, the combination of phytase and 25OHD could induce optimum effects.

This research aims to investigate the effects of dietary konjac glucomannan and κ-carrageenan (SF) on sow performance and suckling piglet gut barrier. Thirty-four sows in late gestation (parity 2–5) were selected at random and grouped into two treatments. The control group (Con group; n = 17) was fed the basal diet; the SF group was fed the same diet supplemented with 0.25% konjac glucomannan + 0.25% κ-carrageenan (SF group; n = 17). The results showed that sows fed the SF diet had a higher feed intake during lactation than the Con group (P < 0.05), and the levels of neuropeptide tyrosine (NPY) (P = 0.006) and acetylcholine enzyme (AChE) (P < 0.05) significantly increased. The fecal microbial analysis indicated that the SF diet had a higher abundance of Subdoligranulum, Holdemanella, and Succinivibrio at the genus level, and the acetate level was significantly increased (P < 0.05). Moreover, SF lowered the level of interleukin-6 (IL-6) in milk (P < 0.05). Regarding suckling piglets, maternal supplementation with SF reduced jejunal IL-6 protein levels in suckling piglets (P < 0.05). In the colon of the piglet, the SF group up-regulated protein levels of occludin (P < 0.05), and the nuclear factor erythroid 2-related factor 2 (Nrf2) (0.05 ≤ P < 0.10), and claudin 4 (CLDN4) (0.05 ≤ P < 0.10) protein levels tended to be up-regulated. Consequently, supplementation of SF in sow diets positively affects lactation feed intake and maternal microflora. Furthermore, the maternal effect improves the jejunum and colon barriers of suckling piglets.

At a global level, the supply of protein sources is insufficient to support the current magnitude of pig production. Moreover, given the exorbitant expense of conventional protein feed options like soybean meal and fish meal, it becomes imperative to promptly explore alternative sources of protein feed for the sustainable advancement of the pig industry. Cottonseed meal, a by-product from the extraction of cottonseed oil, exhibits significant potential as a protein source for pig feed owing to its high protein content, high yield, low cost, well-balanced amino acid composition, and sufficient accessibility. However, cottonseed meal possesses several anti-nutritional factors, especially gossypol, which adversely affect growth and reproductive performance, resulting in the limited utilization of cottonseed meal in pig feed. To maximize the benefits of cottonseed meal and promote its application in pig production, it is imperative to acquire comprehensive knowledge regarding its nutritional value and current utilization. In this review, we initially presented a summary of the nutritional values of cottonseed meal, primary anti-nutritional factors, and effective approaches for improving its utilization as a protein source feed. Subsequently, we comprehensively summarized the latest research progress of cottonseed meal application in pig nutrition over the past decade. The outcome of this review serves as a theoretical foundation and practical guidance for the research and application of cottonseed meal in pig nutrition and promotes the reduction of soybean meal utilization in the pig industry.