A low-carbon high inulin diet improves intestinal mucosal barrier function and immunity against infectious diseases in goats.

INTRODUCTION

Abrupt weaning is a major stressful event, contributing to intestinal abnormalities and immune system dysfunction in weaned kids. Inulin is a prebiotic fiber with many positive functions, including promoting intestinal fermentation and enhancing host immunity in monogastric animals. However, the effects of a high-inulin, energy-rich diet on ruminal fermentation characteristics, methane emission, growth performance, and immune systems of weaned kids have not been investigated.

METHODS

A fully automated fermentation system was used to investigate ruminal fermentation characteristics and methane emission of a mixed substrate of inulin and fat powder (1.31: 1) in comparison with maize grain-based starter concentrate. During a 1-week adaptation and 4-week trial phase, 18 weaned kids (8.97 ± 0.19 kg) were randomly assigned to two groups, one with a conventional diet (83% maize grain; CON) and the other with a low-carbon, high-inulin diet (41.5% maize grain, 14.4% fat powder, 18.9% inulin; INU).

RESULTS

In the rumen fermentation experiment, the total gas production was not different ( > 0.05); however, a lower ( < 0.05) methane production was observed for INU as compared to CON. The average daily gain and the ratio of feed intake and growth performance of kids fed with INU were higher ( < 0.05) than those fed with CON. Serum concentrations of alanine transaminase (ALT) and lactate dehydrogenase (LDH) were lower ( < 0.05), whereas the concentration of high-density lipoprotein (HDL) and cholesterol (CHOL) were higher ( < 0.05) in kids fed with the INU diet as compared CON. Dietary inulin significantly increased ( < 0.05) the secretion of immunoglobulins (IgA, IgG, and IgM) and inflammatory cytokines (IFN-γ and IL-10) in ileum tissue. Although no differences ( > 0.05) were observed in mRNA expression of tight junction markers, the INU diet tended to increase ( = 0.09) gene expression of ribosomal protein S6 kinase beta-1 () in the mammalian target of rapamycin () pathway of muscle.

CONCLUSION

Our findings highlighted that a low-carbon high-inulin energy-rich diet could be used as a promising strategy to improve gut immunity and growth performance of weaned kids under abrupt weaning stress and reduce methane production.