Effects of early commercial milk supplement on the mucosal morphology, bacterial community and bacterial metabolites in jejunum of the pre- and post-weaning piglets.

OBJECTIVE: Sow milk (SM) may not be able to meet the piglet's nutritional needs in late lactation. Hence, this study was conducted to investigate the effects of early commercial milk (CM) supplement on the mucosal morphology, bacterial community and bacterial metabolites in jejunum of piglets. METHODS: Ten litters of newborn piglets ([Yorkshire×Landrace]×Duroc) were randomly divided into 2 groups of 5 litters. The piglets in the control group were suckled by the sow (SM), while the piglets in the treatment group (CM supplement) were supplemented with a CM supplement along with suckling from d 4 to d 28 of age. RESULTS: No significant differences were observed about jejunal mucosal morphology on d 28 and d 35 between two groups. On d 28, the activity of lactase in the jejunum was significantly decreased in the CM group, while the activity of sucrase and the ratio of maltase to lactase were significantly increased (p<0.05). On d 35, the activity of maltase in the jejunum was significantly increased in the CM group (p<0.05), and maltase to lactase ratio tended to increase in the CM group (p = 0.065). In addition, piglets in the CM group had a higher abundance of Clostridium XI, Tuicibater, and Moraxella in the jejunum on d 28, while the abundance of Lactobacillus was significantly increased on d 35 (p<0.05). CONCLUSION: The early CM supplement improved the maturation of the jejunum to some extent by enhancing the maltase and sucrase activities. Moreover, the early CM supplement could help maintain the homeostasis of internal environment in jejunum by increasing the microbial-derived metabolites.

The Changes of Colonic Bacterial Composition and Bacterial Metabolism Induced by an Early Food Introduction in a Neonatal Porcine Model.

The impact of an early food introduction on the microbiota composition and microbial metabolism in colon was investigated using a new-born piglet model. At day 4 after birth, 10 litters of piglets were randomly allocated to a sow-rearing group (SR group) and a milk-replacer supplementing group (MRS group) (n = 5). A commercial milk replacer was given to the suckling piglets in the MRS group from the 4th day to the 28th day. Pyrosequencing of the V3-V4 region of the 16S rRNA genes showed that the milk replacer supplementation significantly decreased the relative abundance of Lactobacillus, Clostridium XI, Blautia, Clostridium sensustricto and Escherichia (p = 0.08) in the colon of the piglets, but significantly increased the relative abundance of Paraprevotella on the 28th day. In addition, the abundance of Rumminococcus, Clostridium XlVa, Succiniclasticum, Clostridium IV tended to increase in the MRS group. The concentrations of acetate, propionate, butyrate, valerate and branch-chain fatty acids (BCFAs) in the colonic digesta increased with the milk replacer supplementary in the MRS group. In addition, the milk replacer supplementary increased the expression level of Toll-like receptor 4 (TLR4), but decreased the expression level of interleukin-6 (IL-6) in the colonic mucosa of the piglets. In conclusion, an early food introduction can influence the gut bacterial composition and metabolism, and may further affect the intestinal health by modifying the gene transcription related to the colonic function. These findings may provide some guidelines for the early nutrition supplementation for infants during the lactation period.

Dynamic changes in morphology, gene expression and microbiome in the jejunum of compensatory-growth rats induced by protein restriction.

We previously reported that protein-restricted rats experienced compensatory growth when they were switched to a normal protein diet (NPD). This study aimed to investigate the changes in gene expression and microbiome in the jejunum of compensatory-growth rats. Weaned Sprague-Dawley rats were assigned to an N group, an LN group and an L group. The rats in the L and N groups were fed a low protein diet (LPD) and the NPD respectively. The rats in the LN group were fed with the LPD for 2 weeks, followed by the NPD. The experiment lasted 70 days, and the rats were sacrificed for sampling on days 14, 28 and 70 to determine the jejunal morphology, microbiome and gene expression related to digestive, absorptive and barrier function. The results showed that, although rats in the LN group had temporarily impaired morphology and gene expression in the jejunum on day 14 in response to the LPD, they had improved jejunal morphology and gene expression related to jejunal function on day 28 compared to rats in the N group. This improvement might promote compensatory growth of rats. However, lower expression of genes related to nutrient absorption and undifferentiated villous height (VH) were observed in the jejunum of rats in the LN group on day 70. In contrast, rats in the L group had lower VH on day 28 and day 70, while the expression of absorptive genes increased on day 28 compared to rats in the N group. Additionally, dramatic microbial changes in the jejunum of compensatory-growth rats were observed, principally for Lactobacillus, Streptococcus, Corynebacterium and Staphylococcus. Moreover, the abundance of Lactobacillus, Streptococcus, Corynebacterium and Staphylococcus significantly correlated with gene expression in the jejunum as revealed by the correlation analysis.

The role of microbiota in compensatory growth of protein-restricted rats.

Compensatory growth is a physiological phenomenon found in both humans and animals. However, the underlying mechanisms are unclear. In this study, for the first time, we investigated the role of microbiota in compensatory growth induced by protein restriction using a rat model. Weaned Sprague-Dawley rats were fed a low protein diet (L group), a normal protein diet (N group) and a low protein diet for 2 weeks followed by a normal protein diet (LN group). The results showed that in contrast with the inhibited growth of rats in the L group, compensatory growth was observed in the LN group. Meanwhile, rats in the LN group had increased concentrations of total short chain fatty acids, particularly butyrate, and an altered bacterial composition with modified abundances of Peptostreptococcaceae, Bifidobacteriaceae, Porphyromonadaceae and Prevotellaceae in the colonic content. Furthermore, gene expression analysis indicated that the rats that experienced compensatory growth had improved barrier function and innate immune function in the colon. Our data revealed the importance of colonic microbiota in achieving compensatory growth.