Effect of dietary Bacillus subtilis on growth performance and serum biochemical and immune indexes in weaned piglets

Abstract

This study evaluated the effect of dietary Bacillus subtilis on growth performance of weaned piglets, and also the effects of dietary B. subtilis on serum biochemical parameters and serum growth hormone, cytokines and immunoglobulins levels after Escherichia coli challenge. A total of 24 weaned piglets were housed in single pens and fed the basal diet (NC) either with or without B. subtilis (BS) or chlortetracycline (PC) for a 14-day period. All piglets were orally inoculated with E. coli K88 on day 14, and the blood samples were collected at 6 hours post-challenge. The results showed that dietary BS increased average daily gain and reduced feed conversion rate compared to the NC group. In addition, piglets in the BS group had higher serum growth hormone levels, total protein concentrations and alkaline phosphatase activities than the NC group did. Moreover, dietary BS decreased concentrations of serum IFN-γ and TNF-α and increased concentrations of serum IL-10 compared to the NC group, and BS supplementation increased serum IgA and IgG concentrations compared to those of the NC group. In conclusion, dietary B. subtilis improved growth performance of weaned piglets and attenuated the serum immune response to E. coli challenge.