Abstract
The broiler chicks provide the major portion of daily food items. The current study aimed to investigate the effects of Bacillus subtilis (BS) on broiler chicken gut microflora diversity, digestive enzyme activity and expression of Toll-like receptors (TLRs). A total of 240 crossbred broiler chickens were randomly allocated into 4 groups with 3 replicates. The groups were named as control group (basal diet, BD), group Ⅰ (BD with 300 g/d BS,1.08×107 CFU/kg), group Ⅱ (BD with 600 g/d BS, 2.16×107 CFU/kg), and group Ⅲ (BD with 900 g/d BS, 3.24×107 CFU/kg). Samples were collected at the 21st day. The difference of α diversity and β diversity between control group and treatment groups were not significant, but the abundance of some microorganisms in the treatment groups were improved, and the core microorganisms were different between groups. In comparison of control group, the protease activity in ileum of experimental groups was significantly increased (p < 0.05). Protease activity in ileum of group Ⅱ and Ⅲ was improved by 22.59% (p < 0.01) and 14.49% (p < 0.05). The amylase activity in ileum of treatment groups were also significantly increased (p < 0.05). Amylase activity of group Ⅱ was increased by 41.85% (p < 0.01) in comparison to control, group Ⅰ and Ⅲ. Expression of TLR1A and TLR7 in the jejunum and caecum of treatment groups were significantly up-regulated while their expression in ileum was decreased. Similarly, the expression of TLR1B gene was significantly improved in the ileum, and down regulated in the cecum. Transcription levels of TLR2A and MyD88 in jejunum, liver, spleen and kidney were significantly increased, but their expression was significantly lower in the ileum and cecum. The TLR2B, TLR3, TLR4, TLR15, TLR21 expression were also significantly modulated in various organ of broiler chicken. The most important inflammatory factor such as IL-1β expressions in spleen and kidney were significantly increased in the current data. Bacillus subtilis could not regulate the caecal microflora diversity, but improved amount of some gut probiotics such as lactobacillus, the digestive enzyme activity, regulate some immunogenic expressions and enhance the immune capacity of animal. We hope that the impact of this data will explore the diseases control and feeding quality of broiler chicks at industrial level.
Effects of Probiotic Complex on Performance, Blood Biochemical and
Immune Parameters, Digestive Enzyme Activity, Fecal Microbial Population and
Noxious Gas Emission in Broiler Chicks