Bacillus amyloliquefaciens BLCC1-0238 Alone or in Combination with Mannan-Oligosaccharides Alleviates Subclinical Necrotic Enteritis in Broilers

Subclinical necrotic enteritis (SNE) is a severe intestinal disease in broilers which brings huge economic losses to poultry industry. Herein, the effects of Bacillus amyloliquefaciens BLCC1-0238 ( B. amyloliquefaciens BLCC1-0238) alone or in combination with mannan-oligosaccharides (MOS) on the SNE challenge model in broilers were comprehensively explored. A total of 360 broilers were randomly divided into 4 groups, including an SNE infection control (IC), an antibiotic pretreatment control (AC), a B. amyloliquefaciens BLCC1-0238 pretreatment (BP), and a B. amyloliquefaciens BLCC1-0238 + MOS pretreatment (BMP). The results showed that compared with the IC, three pretreatment groups significantly improved the growth performance, lowered the overall mortality, and reduced intestinal mucosal lesions in broilers. Additionally, the expression levels of claudin-3 and peroxisome proliferator-activated receptor-gamma coactivator-1α in the BP and BMP groups and the levels of mucin-2 and mechanistic target of rapamycin in the BMP group were significantly upregulated compared with the IC. By contrast, the expression levels of interferon-γ, interleukin-10, and secretory immunoglobulin A in the BP and BMP groups were significantly downregulated. In conclusion, these findings show that B. amyloliquefaciens BLCC1-0238 in combination with MOS can exert synergetic effects by the interplay between them on improving growth performance and combating the SNE infection in broilers.