The objectives of the current study were to compare the difference between standardized ileal digestibility (SID) and standardized total tract digestibility (STTD) of phosphorus (P) in pigs using published data and investigate the factors that affect the hindgut disappearance of P in pigs. A total of 156 observations from 32 experiments that determined the apparent ileal digestibility and total tract digestibility of P in pigs were collected. The SID and STTD of P were calculated by accounting for basal endogenous losses of P. Standardized hindgut disappearance (SHD) of P was determined by subtracting the SID of P from the STTD of P. The Chi-square test was performed to investigate the association between SHD of P and categorical variables, including the use of phytase, the use of inorganic P sources, the use of corn-soybean meal-based diets, and body weight (BW) of pigs. To determine the effects of the SID of P on the SHD of P, a linear equation for the SHD of P was developed using the SID of P as an independent variable. The BW of pigs ranged from 10.0 to 104.8 kg and the SHD of P ranged from −22.8% to 39.8%. The STTD of P was greater than the SID of P (47.1% vs. 49.7%; P = 0.019). Based on the Chi-square analysis, the supplementation of inorganic P sources tended to result in a higher occurrence of a positive value for the SHD of P (P = 0.079). In addition, the occurrence of a positive value in the SHD of P was lower when the BW of pigs was below 30 kg. However, as the BW of pigs increased, the occurrence of a positive value in the SHD of P increased (P = 0.061). A regression analysis of the SHD of P against the SID of P in pigs indicated that the SHD of P decreased as the SID of P increased in pigs (r² = 0.17; P < 0.001). In conclusion, the STTD of P is greater than the SID of P in pigs, and the SHD of P depends on the diet composition, the amount of P entering the large intestine, and the BW of the pigs.

A six-week feeding trial was carried out to determine the feasibility of cottonseed oil (CSO) as a viable substitute for fish oil (FO) in the commercial diet of swimming crabs. Ninety healthy swimming crabs (initial body weight 34.28 ± 0.59 g) were randomly assigned to 90 plastic baskets. Three isonitrogenous and isolipidic diets (450 g/kg protein and 120 g/kg lipid) were formulated replacing FO with CSO at 0%, 50% and 100% (CSO-0, CSO-50, and CSO-100), respectively. Each diet was randomly allocated to three replicates, each consisting of 10 crabs. Results indicated that crabs fed with CSO-100 diet had the lowest the percent weight gain (PWG), specific growth rate (SGR) and survival among all treatments (P < 0.05). Albumin (ALB), glucose (GLU), triglyceride (TAG), total cholesterol (T-CHO), low-density lipoprotein cholesterol (LDL-C), non-esterified fatty acid (NEFA) contents and alkaline phosphatase (ALP), alanine amino transferase (ALT) activity in hemolymph were significantly affected by dietary substitution of FO with CSO (P < 0.05). The contents of total saturated fatty acids (SFA), total mono-unsaturated fatty acids (MUFA) and total long-chain polyunsaturated fatty acids (LC-PUFA) in the hepatopancreas and muscle were negatively correlated with the substitution level, whereas total n-6 polyunsaturated fatty acids (n-6 PUFA) and linoleic acid (18:2n-6) contents increased significantly with increasing levels of dietary substitution of FO with CSO (P < 0.05). Dietary substitution of FO with CSO resulted in changes in the composition of volatile substances in muscle, with 16 volatile substances in muscle significantly affected (P < 0.05). The relative expression of genes related to lipid synthesis such as fatty acid synthase (fas), acetyl-CoA carboxylase (acc) and glycerol-3-phosphate acyltransferase 1 (gpat1) in the hepatopancreas were significantly up-regulated in the CSO-50 group compared to other treatment groups (P < 0.05). The relative expression of fatty acid anabolism-related genes fatty acyl desaturase 2 (fads2) and elongase 4 (elovl4) were significantly down-regulated with the increase of dietary substitution of FO with CSO (P < 0.05). In conclusion, 50% substitution with CSO had no negative effects on growth performance, promoted lipid synthesis and metabolism, facilitated lipid accumulation. However, complete substitution of FO with CSO inhibited fatty acid synthesis and metabolism, resulting in a lower tissue LC-PUFA content and an altered composition of muscle volatiles.

The purpose of this study was to gain insight into the mechanism of iron dextran (DexFe) absorption in the intestines. A total of 72 piglets (average BW = 7.12 ± 0.75 kg, male to female ratio = 1:1) weaned at 28 d of age were randomly divided into two treatment groups with six replicates for each group. The experimental diets included the basal diet supplemented with 100 mg/kg iron dextran (DexFe group) and the basal diet supplemented with 100 mg/kg FeSO₄·H₂O (CON group). The experiment lasted for 28 d. The piglets' intestinal iron transport was measured in vitro using an Ussing chamber. Porcine intestinal epithelial cell line (IPEC-J2) cells were used to develop a monolayer cell model that explored the molecular mechanism of DexFe absorption. Results showed that compared to the CON group, the ADG of pigs in the DexFe group was improved (P = 0.022), while the F/G was decreased (P = 0.015). The serum iron concentration, apparent iron digestibility, and iron deposition in the duodenum, jejunum, and ileum were increased (P < 0.05) by dietary DexFe supplementation. Piglets in the DexFe group had higher serum red blood count, hemoglobin, serum iron content, serum ferritin and transferrin levels and lower total iron binding capacity (P < 0.05). In the Ussing chamber test, the iron absorption rate of the DexFe group was greater (P < 0.001) than the CON group, and there was no significant difference between the DexFe group and the glucose group (P > 0.05). Furthermore, when compared to the CON group, DexFe administration improved (P < 0.05) SLC2A5 gene and glucose transporter 5 (GLUT5) protein expression but had no effect (P > 0.05) on SLC11A2 gene or divalent metal transporter 1 (DMT1) protein expression. Once the GLUT5 protein was suppressed, the iron transport rate and apparent permeability coefficient were decreased (P < 0.05) in IPEC-J2 monolayer cell models. The findings suggest the effectiveness of DexFe application in weaned piglets and revealed for the first time that DexFe absorption in the intestine is closely related to the glucose transporter GLUT5 protein channel.

Delivery and weaning are major stressful events in sows and piglets, adversely affecting production and growth performance and causing economic losses to swine farms. Probiotics as safe antibiotic alternatives have great potential for use across all stages of livestock farming. Here, 18 pregnant sows from clinical farms randomly were divided into two groups: one fed a basal diet (CON group) and the other fed a basal diet plus a probiotic mixture CBB-mix (containing 1×10¹² CFU/g of Lactobacillus johnsonii [CJ21], 1×10⁹ CFU/g of Bacillus subtilis [BS15], and 1×10⁹ CFU/g of Bacillus licheniformis [BL21]), for 20 days before delivery. The effects of maternal CBB-mix supplementation on sow colostrum metabolome and offspring piglets' clinical performance, immune status, and gut microbiota were investigated. Additionally, 177 piglets were randomly divided into 4 groups, including CC group (piglets and sows fed a basal diet, n = 40 from 5 litters), CP group (piglets fed the basal diet plus CBB-mix and sows fed the basal diet, n = 38 from 4 litters), PC group (piglets fed the basal diet and sows fed the basal diet plus CBB-mix, n = 50 from 4 litters), and PP group (both piglets and sows fed the basal diet plus CBB-mix, n = 49 from 5 litters). Among that, CP and PP groups were added CBB-mix in the creep feed from 11 days of age for 18 days to study the direct effects of CBB-mix on the growth performance of piglets. Maternal CBB-mix supplementation improved sow production performance, including litter size at birth and litter weight at birth (P < 0.05). Piglets born from CBB-mix-fed sows exhibited increased litter size at weaning and reduced diarrhea incidence from 1 to 10 days of age (P < 0.05). Additionally, systemic immune status and antioxidant capabilities were improved in both sows and piglets. Maternal CBB-mix supplementation reconstituted the gut microbiota structure and increased the Sobs index and Shannon index of fecal microbiota in both sows and piglets (P < 0.05). The relative abundance of Firmicutes and Clostridium_sensu_stricro_1 in sow feces was decreased after feeding CBB-mix (P < 0.05). In piglets, 10-day-old feces had relatively more Lactobacillus but less Escherichia-Shigella than 1-day-old feces (P < 0.05), indicating that maternal feeding CBB-mix alone affects the gut microbiota community of offspring piglets via the gut–breast axis. Piglets born from CBB-mix-fed sows had continuously decreased the relative abundance of fecal Escherichia-Shigella at 28 days of age (P < 0.05). Consistently, the metabolite profile in sow milk was also changed by CBB-mix. Colostrum metabolome showed that CBB-mix significantly regulated tryptophan metabolism and primary bile acid biosynthesis. Our data demonstrated that maternal CBB-mix supplementation effectively improved the production performance of sows and their offsprings' growth performance. Through the gut–breast axis (interaction between gut microbiota and mammary glands), feeding CBB-mix to sows impacted the gut microbiota of their offspring. This study provides strategy and evidence for maternal probiotic supplementation to improve immune status and gut microbiota homeostasis in response to delivery and weaning.

Aflatoxin B1 (AFB1), an important fungal toxin, exists mainly in plant feed ingredients and animals consuming feed contaminated with AFB1 will have reduced growth and impaired health condition mainly due to oxidative stress and reduced immunity. Our previous study found that AFB1 caused oxidative damage and inhibited muscle development of zebrafish. 4-Methylesculetin (4-ME), a coumarin derivative, is now used in biochemistry and medicine widely because of its antioxidant function. Whether 4-ME could alleviate the inhibition of muscle development in grass carp induced by AFB1 has not been reported. In this experiment, 720 healthy grass carp (11.40 ± 0.01 g) were randomly divided into 4 groups with 3 replicates of 60 fish each, including control group, AFB1 group (60 μg/kg diet AFB1), 4-ME group (10 mg/kg diet 4-ME), and AFB1+4-ME group (60 μg/kg diet AFB1 + 10 mg/kg 4-ME diet), for a 60-d growth experiment. In vitro, we also set up 4 treatment groups for grass carp primary myoblast, including control group, AFB1 group (15 μmol/L AFB1), 4-ME group (0.5 μmol/L 4-ME) and AFB1+4-ME group (15 μmol/L AFB1+0.5 μmol/L 4-ME). The results showed that dietary AFB1 decreased growth performance of grass carp, damaged the ultrastructure and induced oxidative damage in grass carp muscle, and significantly decreased the mRNA and protein expression levels of myogenin (MyoG), myogenic differentiation (MyoD), myosin heavy chain (MYHC), as well as the protein expression levels of laminin β1, fibronectin and collagen I (P < 0.05), significantly activated the protein expression levels of urokinase-type plasminogen activator (uPA), matrix metalloproteinase-2 (MMP-2), matrix metalloproteinase-9 (MMP-9) and phosphorylate-38 mitogen-activated protein kinase (p38 MAPK) both in grass carp muscle and grass carp primary myoblast (P < 0.05). Supplementation of AFB1 with 4-ME significantly improved the growth performance inhibition and alleviated the muscle fiber development inhibition and extracellular matrix (ECM) degradation in grass carp induced by AFB1 (P < 0.05). The present results revealed that supplementation of AFB1 contaminated feed with 4-ME reduced the inhibition of growth and muscle development by alleviating AFB1-induced ECM degradation in grass carp, which might be related to the p38 MAPK/uPA/MMP/ECM pathway. The results implied that 4-ME could be used as a valuable mycotoxin scavenger in animal feed.

In lambs, weaning imposes stress that can contribute to impaired rumen epithelial barrier functionality and immunological dysregulation. In this study, the effects of a yeast co-culture consisting of Saccharomyces cerevisiae and Kluyveromyces marxianus (NM) on rumen health in lambs was evaluated, with a focus on parameters including growth performance, ruminal fermentation, and epithelial barrier integrity, ruminal metabolic function, and the composition of the ruminal bacteria. In total, 24 lambs were grouped into four groups of six lambs including a control (C) group fed a basal diet, and N, M, and NM groups in which lambs were fed the basal diet respectively supplemented with S. cerevisiae yeast cultures (30 g/d per head), K. marxianus yeast cultures (30 g/d per head), and co-cultures of both yeasts (30 g/d per head), the experiment lasted for 42 d. Subsequent analyses revealed that relative to the C group, the average daily gain (ADG) of lambs in the NM group was significantly greater and exhibited significant increases in a range of mRNA relative expression including monocarboxylate transporter 1 (MCT1), (Na⁺)/hydrogen (H⁺) exchanger 1 (NHE1), (Na⁺)/hydrogen (H⁺) exchanger 3 (NHE3), proton-coupled amino acid transporter 1 (PAT1), vacuolar H⁺-ATPase (vH+ ATPase), claudin-1, occludin in the rumen epithelium (P < 0.05). Compared with the C group, the pH of the rumen contents in the NM group was significantly decreased , and the concentrations of acetate, propionate, and butyrate were significantly increased (P < 0.05). Analysis of the rumen bacteria showed that the NM group exhibited increases in the relative abundance of Prevotella, Treponema, Moryella, Fibrobacter, CF231 and Ruminococcus (P < 0.05). Metabolomics analyses revealed an increase in the relative content of phthalic acid and cinnamaldehyde in the NM group as compared to the C group (P < 0.05), together with the greater relative content of L-tyrosine, L-dopa, rosmarinic acid, and tyrosol generated by the tyrosine metabolic pathway (P < 0.05). Spearman's correlation analyses revealed relative abundance levels of Fibrobacter and Ruminococcus were positively correlated with the mRNA relative expression levels of PAT1, NHE3, and zonula occluden-1 (ZO-1), as well as with tyrosol, phthalic acid, and cinnamaldehyde levels (P < 0.05). Ultimately, these results suggest that dietary supplementation with NM has a wide range of beneficial effects on weaned lambs and is superior to single bacterial fermentation. These effects include improvements in daily gain and rumen epithelial barrier integrity, as well as improvements in the composition of the rumen microbiome, and alterations in tyrosine metabolic pathways.

The rumen is an important organ that enables ruminants to digest nutrients. However, the biological mechanism by which the microbiota and its derived fatty acids regulate rumen development is still unclear. In this study, 18 female Haimen goats were selected and slaughtered at d 30, 60, and 90 of age. Multi-omics analyses (rumen microbial sequencing, host transcriptome sequencing, and rumen epithelial metabolomics) were performed to investigate host–microbe interactions from preweaning to postweaning in a goat model. With increasing age, and after the introduction of solid feed, the increased abundances of Prevotella and Roseburia showed positive correlations with volatile fatty acid (VFA) levels and morphological parameters (P < 0.05). Epithelial transcriptomic analysis showed that the expression levels of hub genes, including 3-hydroxy-3-methylglutaryl-CoA synthase isoform 2 (HMGCS2), enoyl-CoA hydratase, short chain 1 (ECHS1), and peroxisome proliferator activated receptor gamma (PPARG), were positively associated with animal phenotype (P < 0.05). These hub genes were mainly correlated to VFA metabolism, oxidative phosphorylation, and the mammalian target of rapamycin (mTOR) and peroxisome proliferator activated receptor (PPAR) signaling pathways (P < 0.05). Moreover, the primary metabolites in the epithelium changed from glucose preweaning to (R)-3-hydroxybutyric acid (BHBA) and acetoacetic acid (ACAC) postweaning (P < 0.05). Diet and butyrate were the major factors shaping epithelial metabolomics in young ruminants (P < 0.05). Multi-omics analysis showed that the rumen microbiota and VFA were mainly associated with the epithelial transcriptome, and that alterations in gene expression influenced host metabolism. The “butanoate metabolism” pathway, which transcriptomic and metabolomic analyses identified as being upregulated with age, produces ketones that regulate the “oxidative phosphorylation” pathway, which could provide energy for the development of rumen papillae. Our findings reveal the changes that occur in the rumen microbiota, host transcriptome, and metabolome with age, and validate the role of microbiota-derived VFA in manipulating host gene expression and subsequent metabolism. This study provides insight into the molecular mechanisms of host–microbe interactions in goats and supplies a theoretical basis and guidance for precise nutritional regulation during the critical time window for rumen development of young ruminants.

Dietary sanguinarine (SAN) can enhance the growth performance of poultry and livestock, but the regulatory mechanism of the SAN monomer on intestinal homeostasis and how it promotes growth performance has not yet been clarified. In this study, 200 chickens were divided into four groups and fed different doses of SAN (0, 0.225, 0.75, 2.25 mg/kg) for transcriptome and microbiota analysis. The data showed that different doses of SAN supplementation increased the feed conversion rate (FCR) of 22 to 42 d old and 1 to 42 d old broilers (P < 0.01), and 0.225 mg/kg SAN reduced the contents of alanine aminotransferase (ALT), aspartate aminotransferase (AST), creatinine (CREA) and blood urea nitrogen (BUN) in serum (P < 0.01). Dietary SAN increased the villus height and the villus height/crypt depth (V/C) ratio in the ileum (P < 0.01). The levels of tight junction proteins (zonula occludens-1, occludin and claudin-1) were up-regulated in the ileum and cecum (P < 0.01) and the levels of immunoglobulin (Ig) A, IgM, IgG, interleukin (IL)-4, IL-10 and interferon (IFN)-γ were up-regulated in the serum and ileum (P < 0.01). RNA-seq analysis revealed 385 differentially expressed genes (DEGs) (|log₂ fold change| ≥ 1, FDR < 0.05) between the SAN group and CON group. Kyoto Encyclopedia of Genes and Genomes pathway analysis showed 15 pathways mostly associated with the immune system. Additionally, the reverse transcription-PCR results showed that the relative mRNA expression of β-defensin and mucin 2 were up-regulated (P < 0.01) and Toll-like receptor (TLR2 and TLR4) mRNA expression were down-regulated by SAN (P < 0.01), which was consistent with the transcriptomic analysis. Western blot analysis also showed that SAN reduced the expression of inflammatory proteins such as TLR4, nuclear factor-kappa B and IL-1β in the ileum (P < 0.01). In addition, at the genus level, SAN significantly increased the relative abundance of bacteria (Bacteroides, unclassified_f__Lachnospiraceae, Lactobacillus and Romboutsia) involved in acetate and butyrate production in the cecum, which are associated with enhanced intestinal immune function and maintaining intestinal health. In conclusion, SAN ameliorates the growth performance of broilers, enhances intestinal immune function, regulates the structure of microbiota and maintains intestinal health.

The use of reduced protein diets in broiler chicken production provides potential benefits for performance and environmental footprint of production. The effectiveness of β-Mannanase supplementation in wheat and soy based standard protein (SP) and reduced protein (RP) diets was tested for growth performance, nutrient utilisation and selected intestinal gene expression of broiler chickens. In a 2 × 2 factorial arrangement of treatments, two main factors included dietary protein (standard and reduced protein) and β-Mannanase supplementation (with or without). All diets contained phytase and carbohydrases (xylanase and glucanase). A total of 480 Ross 308 male off-sex day-old chickens were assigned to the four experimental diets in a 35-d study. Each diet was replicated 12 times with 10 birds per replicate. Using an additional 160 birds, separate apparent metabolizable energy (AME) and nutrient digestibility assays were undertaken for the 4 experimental diets from d 21 to 24 of age. Selected genes involved in gut integrity, inflammation and immune response were quantified using quantitative PCR assays. There was no interaction between β-Mannanase and dietary protein for any of the studied parameters except ileal viscosity. Enzyme had no effect on feed intake but tended to increase body weight gain (BWG) from d 0 to 35 of age (P = 0.079). Birds fed RP diet consumed more feed when assessed from d 0 to 35 of age (P = 0.029). At the same time, β-Mannanase tended to reduce feed conversion ratio independent of dietary protein (P = 0.069). β-Mannanase reduced ileal viscosity of the birds fed RP diet (P < 0.001). Reducing dietary protein increased nitrogen retention, nitrogen digestibility coefficient and digestibility coefficients of 11 amino acids (P < 0.001). β-Mannanase significantly improved digestibility coefficients of nitrogen and Arg, Gly, Thr, Lys, and Ile (P < 0.05). Dietary treatments had no effect on AME or gene expression of selected tight junction proteins, interleukin-10, interleukin-1β, mucin-2 and nuclear factor-kappa B. In conclusion, supplementation of β-Mannanase tended to improve feed efficiency and increased nutrient digestibility of broilers fed wheat-based diets independent of a moderate reduction in dietary protein. Complementary mode of actions of β-Mannanase for intestinal health requires further investigation.