Effects of spore-forming Bacillus probiotics on growth performance, intestinal morphology, and immune system of broilers housed on deep litter

Abstract

Aim of the study: to evaluate the effects of feed supplementation of Bacillus subtilis KATMIRA1933, B. subtilis KB41, and Bacillus amyloliquefaciens KB54 probiotics on growth performance, biochemical blood parameters, intestinal morphology, and the immune system of Ross 308 broilers housed on deep litter. Methods and Results: a total of 160 newly hatched Ross 308 broilers were involved in the 42-day-long study with evaluation of growth performance at 7, 14, 21, 28, 35, and 42 days and biochemical blood analysis, histological investigation of jejunum tissues and analysis of IL-6 and IL-10 gene expression of broilers at 42 days. As a result, probiotic KB41 significantly improved growth performance on the 42nd day of the experiment (p<0.01), increased the number of Lactobacillus bacteria in the ceca (p=0.03), and promoted IL-6 and IL-10 genes expression in the spleen of the chickens (p<0.01). The results of this study generally correspond to our previous study, which included an evaluation of Bacillus-based KB41 and KB54 probiotics on production performance and the immune system of broilers housed in cages, although the effects are less prominent. Conclusions: less prominent effects are probably linked to the colonization of the broilers' gastrointestinal tract with unknown bacilli of apparent environmental origin, as the broilers were housed in standard conditions. Significance and Impact of Study: this study provides more evidence of B. subtilis KB41 and B. amyloliquefaciens KB54 effectiveness in poultry.