Differential Effect of Dietary Fibers in Intestinal Health of Growing Pigs: Outcomes in the Gut Microbiota and Immune-Related Indexes

Comparison between Organic and Inorganic Zinc Forms and Their Combinations with Various Dietary Fibers in Respect of the Effects on Electrolyte Concentrations and Mucosa in the Large Intestine of Pigs

This study aimed to determine the effects of Zn sources, used with potato fiber (PF) or lignocellulose (LC), on electrolyte concentration and the mucus layer in the large intestine of pigs. The experiment involved 24 barrows with an initial body weight of 10.8 ± 0.82 kg, divided into four groups fed the following diets: LC and ZnSO4, LC and Zn glycinate (ZnGly), PF and ZnSO4, or PF and ZnGly. Fiber supplements provided 10 g crude fiber/kg diet, while Zn additives introduced 120 mg Zn/kg diet. After four weeks of feeding, the pigs were sacrificed and digesta and tissue samples were taken from the cecum and colon. PF increased the water content and decreased the phosphorus concentration in the large intestine in comparison with LC. PF also increased calcium, iron, and chloride concentrations in the descending colon. Mucus layer thickness and histological parameters of the large intestine were not affected. ZnGly diets increased MUC12 expression in the cecum as compared to the LC-ZnSO4 group. In the ascending colon, the PF-ZnGly diet increased MUC5AC expression, while both PF groups had greater MUC20 expression in comparison with the LC-ZnSO4 group. In the transverse colon, the LC-ZnGly group and both PF groups had higher MUC5AC expression in comparison with the LC-ZnSO4 group, and both ZnGly groups had higher MUC20 expression than ZnSO4 groups. PF and ZnGly increased MUC4 and MUC5AC expression in the descending colon. PF and ZnGly may exert a beneficial effect on colon health in pigs by upregulating the expression of the MUC5AC and MUC20 genes and are more effective than LC and ZnSO4.

Influences of wheat bran fiber on growth performance, nutrient digestibility, and intestinal epithelium functions in Xiangcun pigs

Dietary fiber (DF) has long been looked as an essential "nutrients" both for animals and humans as it can promote the intestinal tract development and modulate the intestinal epithelium functions and the gut microbiota. This study was conducted to investigate the influences of wheat bran fiber (WBF) on growth performance and intestinal epithelium functions in Xiangcun pigs. Twenty Xiangcun pigs with 60 days of age were divided to two groups and exposed to a basal diet (BD) or BD containing 4.3% wheat bran fiber (WFD). WFD improved the average daily gain (ADG) and feed-to-gain ratio (F:G) (p < 0.01). Moreover, WFD lowered the serum triglyceride (TC), d-lactate, and malonicdialdehyde (MDA) concentrations, but significantly improved the glutathione (GSH) activity and total antioxidant capacity (T-AOC) (p < 0.05). Interestingly, WFD observably improved the villus height (VH) and the villus height to crypt depth ratio (V/C) in the small intestine (p < 0.05). The jejunal sucrase and ileal maltase activities were higher in the WFD group (p < 0.05). WFD markedly elevated the tight junction protein ZO-1 and claudin-1 expression levels in the jejunum and ileum (p < 0.05). The sodium/glucose co-transporter 1 (SGLT1), glucose transporter 2 (GLUT2), and fatty acid transport proteins 4 (FATP-4) expression levels in jejunum and ileum were also elevated under WFD (p < 0.05). WFD decreased the IL-6 impression level in the duodenum and ileum, but significantly increased the IL-10 expression levels in jejunum and ileum (p < 0.05). Moreover, WFD reduced the abundance of E. coli, but elevated the abundances of beneficial microorganisms (e.g. Lactobacillus and Bacillus) and the production microbial metabolites (e.g. propionic acid and butyrate acid) in the cecum (p < 0.05).

Effects of Oat Bran Addition on the Growth Performance and Intestinal Health of Nile Tilapia (Oreochromis niloticus) Exposed to Copper Ions

This study investigated the effects of the oat bran addition on the growth performance and intestinal health of Nile tilapia (Oreochromis niloticus) exposed to copper ions. Four groups of diets containing 0%, 5%, 10%, and 20% oat bran were fed to Nile tilapia for four weeks. The results showed that oat bran had a dose-dependent effect on the growth performance of Nile tilapia. The addition of oat bran can increase the relative abundance of Delftia, which is capable of degrading heavy metals in the intestinal tract and alleviating the intestinal damage caused by copper ion stress. Compared to the control group, the 5% oat bran group had an increased intestinal antioxidant capacity. The relative gene expression of proinflammatory factors (NF-κB, IL-1β) was significantly downregulated in the 5% oat bran group (P < 0.05), and the relative gene expression of anti-inflammatory factors (TGF-β), HIF-1α, occludin, and claudin was significantly upregulated (P < 0.05). In conclusion, we suggest that 5% oat bran should be added to the diet to improve the growth performance of Nile tilapia and alleviate the negative effects of copper ion stress on intestinal health.

Employing pigs to decipher the host genetic effect on gut microbiome: advantages, challenges, and perspectives

The gut microbiota is a complex and diverse ecosystem comprised of trillions of microbes and plays an essential role in host's immunity, metabolism, and even behaviors. Environmental and host factors drive the huge variations in the gut microbiome among individuals. Here, we summarize accumulated evidences about host genetic effect on the gut microbial compositions with emphases on the correlation between host genetic kinship and the similarity of microbial compositions, heritability estimates of microbial taxa, and identification of genomic variants associated with the gut microbiome in pigs as well as in humans. A proportion of bacterial taxa have been reported to be heritable, and numerous variants associated with the diversity of the gut microbiota or specific taxa have been identified in both humans and pigs. LCT and ABO gene have been replicated in multiple studies, and its mechanism have been elucidated clearly. We also discuss the main advantages and challenges using pigs as experimental animals in exploring host genetic effect on the gut microbial composition and provided our insights on the perspectives in this area.

The interaction between dietary fiber and gut microbiota, and its effect on pig intestinal health

Intestinal health is closely associated with overall animal health and performance and, consequently, influences the production efficiency and profit in feed and animal production systems. The gastrointestinal tract (GIT) is the main site of the nutrient digestive process and the largest immune organ in the host, and the gut microbiota colonizing the GIT plays a key role in maintaining intestinal health. Dietary fiber (DF) is a key factor in maintaining normal intestinal function. The biological functioning of DF is mainly achieved by microbial fermentation, which occurs mainly in the distal small and large intestine. Short-chain fatty acids (SCFAs), the main class of microbial fermentation metabolites, are the main energy supply for intestinal cells. SCFAs help to maintain normal intestinal function, induce immunomodulatory effects to prevent inflammation and microbial infection, and are vital for the maintenance of homeostasis. Moreover, because of its distinct characteristics (e.g. solubility), DF is able to alter the composition of the gut microbiota. Therefore, understanding the role that DF plays in modulating gut microbiota, and how it influences intestinal health, is essential. This review gives an overview of DF and its microbial fermentation process, and investigates the effect of DF on the alteration of gut microbiota composition in pigs. The effects of interaction between DF and the gut microbiota, particularly as they relate to SCFA production, on intestinal health are also illustrated.

Nourishing neonatal piglets with synthetic milk and Lactobacillus sp. at birth highly modifies the gut microbial communities at the post-weaning stage

The importance of probiotics in pig production is widely recognized. However, the precise role of probiotics in regulating the gut microbiota of piglets has not been assessed extensively. Therefore, we intend to examine whether suckling pigs ingesting with synthetic milk (SM) and probiotics along with mother milk has a carryover effect on its growth and gut health at the post-weaning stage. A total of 40 [Duroc× (Yorkshire× Landrace)] neonates with an initial BW of 1.49 ± 0.28 kg were assigned to one of two treatments groups: control (CON) and treatment (TRT). Control group piglets were nourished with synthetic milk, while TRT group piglets were nourished SM with (1 × 109 CFU/g) Lactobacillus sp. probiotics. The treatment group piglets showed higher (p < 0.05) body weight and daily gain at week 3 than the CON group piglets. 16S metagenome sequencing showed average demultiplexed reads and denoised reads counts of 157,399 and 74,945, respectively. The total ASV taxonomy number classified with a confidence threshold > 70% (default) on sequence alignment with the SILVA v138 reference database was 4,474. During week 1, Escherichia-Shigella, Clostridium sensu stricto 1, and Bacteroides were confirmed as the major dominant bacterial genera in both the groups at the genus level. However, during week 2, the relative proportion of Escherichia-Shigella, Clostridium sensu stricto 1, and Proteobacteria was decreased, while that of Lactobacillus and Bacteroidota was increased in pigs receiving the probiotic supplement. During weeks 2 and 3, Firmicutes, Proteobacteria, and Bacteroidota phyla were dominant in both groups. During week 6, the relative proportion of Proteobacteria was slightly increased in both groups. Furthermore, Prevotella was confirmed as the major dominant bacterial genus in both groups during weeks 3 and 6. This study suggests that nourishing neonatal piglets with synthetic milk and Lactobacillus sp. probiotics from birth to 21 days would be beneficial to enhance the gut health of piglets and to overcome post-weaning mortality.