Bacillus amyloliquefaciens supplementation alleviates immunological stress and intestinal damage in lipopolysaccharide-challenged broilers

• Bacillus amyloliquefaciens improved tight junctions in LPS-treated broilers.
• Bacillus amyloliquefaciens decreased oxidative damage in LPS-treated broilers.
• Bacillus amyloliquefaciens improved intestinal immune in LPS-treated broilers.

The present study investigated the effects of Bacillus amyloliquefaciens (BA) supplementation on the growth performance, intestinal integrity, antioxidant and immune status of broilers challenged with lipopolysaccharide (LPS). 192 one-day-old male Arbor Acre broilers were randomly distributed into four treatments: (1) non-challenged control; (2) LPS-challenged control; (3) LPS-challenged group + 0.5 g/kg of diet; and (4) LPS-challenged group + 1.0 g/kg of diet. Broilers were intraperitoneally injected with either 500 μg/kg body weight of LPS or sterile saline at 16, 18 and 20 d of age. The inclusion of 1.0 g/kg BA alleviated the compromised average daily gain caused by LPS challenge, the body weight gain in 1.0 g/kg BA supplemented group was still significantly lower than that of control (P < 0.05). Similarly, BA supplementation attenuated intestinal morphology impairment, and reduced intestinal malonaldehyde concentration and myeloperoxidase activity after LPS injection (P < 0.05). The 1.0 g/kg BA inclusion prevented the elevation of circulating diamine oxidase activity and reduction of intestinal glutathione concentration induced by LPS challenge (P < 0.05). The BA decreased interleukin (IL)-1β, whereas increased IL-10 at both protein and transcriptional levels in jejunum, and attenuated LPS-induced elevated mRNA expression of jejunal toll-like receptor 4 (P < 0.05). Moreover, inclusion of 1.0 g/kg BA alleviated LPS-induced negative effect on the mRNA abundance of tight junctions (P < 0.05). It can therefore be postulated that BA supplementation alleviates LPS-induced intestinal mucosal damage by improving intestinal integrity and antioxidant and immune status.