Dietary Bacillus spp . enhanced growth and disease resistance of weaned pigs by modulating intestinal microbiota and systemic immunity

Yijie He; Cynthia Jinno; Kwangwook Kim; Zhaohai Wu; Bie Tan; Xunde Li; Rose Whelan; Yanhong Liu

doi:10.1186/s40104-020-00498-3

Dietary Bacillus spp . enhanced growth and disease resistance of weaned pigs by modulating intestinal microbiota and systemic immunity

J Anim Sci Biotechnol. 2020 Sep 15:11:101. doi: 10.1186/s40104-020-00498-3. eCollection 2020.

Authors

Yijie He¹, Cynthia Jinno¹, Kwangwook Kim¹, Zhaohai Wu², Bie Tan³, Xunde Li⁴, Rose Whelan⁵, Yanhong Liu¹

Affiliations

¹ Department of Animal Science, University of California, Davis, CA 95616 USA.
² Institute of Animal Science, Chinese Academy of Agricultural Sciences , Beijing, 100193 China.
³ Key Laboratory of Agro-ecological Processes in Subtropical Region, Institute of Subtropical Agriculture, Chinese Academy of Sciences, Changsha, 410125 China.
⁴ School of Veterinary Medicine, University of California, Davis, CA 95616 USA.
⁵ Evonik Nutrition & Care GmbH, 63457 Hanau-Wolfgang, Germany.

Abstract

Background: Previous research has shown that dietary supplementation of Bacillus spp. probiotics exerts beneficial effects on animals' growth. However, limited studies have evaluated the efficacy of Bacillus spp. on weaned pigs and their effects on host gut health and microbiome, and systemic immunity using a disease challenge model. The objective of this experiment was to investigate the effects of two Bacillus spp. strains (Bacillus subtilis DSM 32540 and Bacillus pumilus DSM 32539) on growth performance, diarrhea, intestinal health, microbiome, and systemic immunity of weaned pigs experimentally infected with an enterotoxigenic Escherichia coli (ETEC).

Results: Pigs in PRO1 (Bacillus subtilis DSM 32540) had greater (P < 0.05) body weight on d 7 and 14 PI, greater (P < 0.05) ADG from d 0 to 7 and d 7 to 14 PI, compared with pigs in CON (Control). Pigs in PRO1 had milder (P < 0.05) diarrhea on d 2 and 3 PI compared with pigs in CON. However, no differences were observed in growth performance and diarrhea score between PRO2 (Bacillus pumilus DSM 32539) and CON groups. Supplementation of PRO1 decreased (P < 0.05) lymphocyte counts on d 7 and 14 PI, compared with CON. Supplementation of PRO1 and PRO2 both reduced (P < 0.05) total coliforms in mesenteric lymph nodes on d 21 PI. Pigs in PRO2 had greater (P < 0.05) goblet cell number and sulfomucin percentage in duodenal villi and greater (P < 0.05) sialomucin percentage in jejunal villi than pigs in CON. Supplementation of PRO1 up-regulated (P < 0.05) MUC2 gene expression in jejunal mucosa and reduced (P < 0.05) PTGS-2 and IL1B gene expression in ileal mucosa on d 21 PI, compared with CON. Pigs in PRO1 had reduced (P < 0.05) relative abundance of families Lachnospiraceae, Peptostreptococcaceae and Pasteurellaceae in the ileum.

Conclusions: Supplementation of Bacillus subtilis DSM 32540 improved growth performance, alleviated diarrhea severity, enhanced gut health, and reduced systemic inflammation of weaned pigs infected with ETEC F18. Although Bacillus pumilus DSM 32539 was able to alleviate systemic inflammation, it had limited impacts on growth performance and severity of diarrhea of ETEC F18 challenged weaned pigs.

Keywords: Bacillus spp.; Diarrhea; Escherichia coli; Gut health; Weaned pigs.