Effects of soybean meal fermented by L. plantarum, B. subtilis and S. cerevisieae on growth, immune function and intestinal morphology in weaned piglets

BACKGROUND: The present study compared the effects of soybean meal fermented by three different probiotics organisms with non-fermented soybean meal on growth performance, serum parameters, immune chemistry and intestinal morphology in weaned piglets. METHODS: One hundred and forty-four 35-day old crossbred (Duroc × Landrace × Yorkshire) piglets were randomly allocated into four different dietary treatments (n = 36 per group) containing 0, 5, 10 and 15% fermented soybean meal. RESULTS: The piglets fed fermented soybean meal showed an increase (p < 0.05) in average daily weight gain and a reduction in feed consumption (p < 0.05).The piglets fed 10 and 15% fermented soybean meal showed the greatest growth improvement with higher levels of serum alkaline phosphatase and total serum proteins. Serum urea nitrogen in the experimental group was significantly lower than control whereas serum IgG, IgM and IgA levels were all significantly higher. Moreover, villus height in the duodenum, jejunum, and ileum was significantly higher (p < 0.05) and the crypt depth was significantly lower (p < 0.05). The levels of the autophagy factor LC3B in piglets showed a downward trend in the jejunum and ileum compared to control. CONCLUSIONS: Fermented soybean meal could significantly improve the growth, immune function and intestinal health in weaned piglets, and the best effective benefits showed in 10% FSBM group. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (10.1186/s12934-017-0809-3) contains supplementary material, which is available to authorized users.