AUTHOR=Du Renjia , Jiao Shengyin , Dai Yue , An Jianbo , Lv Jia , Yan Xiaoni , Wang Juan , Han Bei 

TITLE=Probiotic Bacillus amyloliquefaciens C-1 Improves Growth Performance, Stimulates GH/IGF-1, and Regulates the Gut Microbiota of Growth-Retarded Beef Calves

JOURNAL=Frontiers in Microbiology

VOLUME=9

YEAR=2018

URL=https://www.frontiersin.org/journals/microbiology/articles/10.3389/fmicb.2018.02006

DOI=10.3389/fmicb.2018.02006

ISSN=1664-302X

ABSTRACT=<p>Growth retardation of calves is defined as a symptom of impaired growth and development, probably due to growth hormone disorder as well as natural and environmental factors in livestock. The growth-promoting effects of probiotics were determined in 50 growth-retarded growth calves. They were supplied with <italic>Bacillus amyloliquefaciens</italic> C-1 (Ba, 4 × 10<sup>10</sup>CFU/d, <italic>n</italic> = 16), <italic>B. subtilis</italic> (Bs, 4 × 10<sup>10</sup>CFU/d, <italic>n</italic> = 18), and negative control (NC, <italic>n</italic> = 16) for 30 days. Pre- and post-intervention, the growth performance (weight gain rate, feed intake and feed conversion rate) was analyzed, the serum GH, IGH-1 and immunoglobulin levels were assayed, and the fecal microbiota was detected. Calves in Ba and Bs groups demonstrated increased body weight gain, feed intake and GH/IGF-1 levels, as well as a more efficient feed conversion rate, compared with NC group (<italic>P</italic> &lt; 0.05). Additionally, the abundances of bacteria contributing to the production of energy and SCFAs (short chain fatty acids), including <italic>Proteobacteria, Rhodospirillaceae</italic>, <italic>Campylobacterales</italic>, and <italic>Butyricimonas</italic> were increased compared with NC group (<italic>P</italic> &lt; 0.05, <italic>FDR</italic> &lt; 0.1); and the suspected pathogens, which included <italic>Anaeroplasma</italic> and <italic>Acholeplasma</italic> were decreased (<italic>P</italic> &lt; 0.05, <italic>FDR</italic> &lt; 0.1) in both the Bs and Ba groups. <italic>Akkermansia</italic>, which is involved in the intestinal mucosal immune response, was increased in Bs group after intervention (<italic>P</italic> &lt; 0.05, <italic>FDR</italic> &lt; 0.1), but exhibited no obvious difference in Ba group. The increased bacterial genera in Ba group were <italic>Sphaerochaeta</italic> and <italic>Treponema</italic> (<italic>P</italic> &lt; 0.05, <italic>FDR</italic> &lt; 0.1). These results indicate that the probiotics <italic>B. amyloliquefaciens</italic> and <italic>B. subtilis</italic> exhibited similar therapeutic potential in terms of growth performance by regulating hormones, and improving the intestinal and rumen development in growth-retarded animals.</p>