AUTHOR=Li Cheng-liang , Wang Jing , Zhang Hai-jun , Wu Shu-geng , Hui Qian-ru , Yang Cheng-bo , Fang Re-jun , Qi Guang-hai 

TITLE=Intestinal Morphologic and Microbiota Responses to Dietary Bacillus spp. in a Broiler Chicken Model

JOURNAL=Frontiers in Physiology

VOLUME=9

YEAR=2019

URL=https://www.frontiersin.org/journals/physiology/articles/10.3389/fphys.2018.01968

DOI=10.3389/fphys.2018.01968

ISSN=1664-042X

ABSTRACT=<p>Dietary inclusion of probiotic <italic>Bacillus</italic> spp. beneficially affect the broiler chickens by balancing the properties of the indigenous microbiota causing better growth performance. The effects of three <italic>Bacillus</italic> spp. on the growth performance, intestinal morphology and the compositions of jejunal microflora were investigated in broiler chickens. A total of 480 1-day-old male Arbor Acres broilers were randomly divided into four groups. All groups had six replicates and 20 birds were included in each replicate. The control birds were fed with a corn-soybean basal diet, while three treatment diets were supplemented with <italic>Bacillus coagulans</italic> TBC169, <italic>B. subtilis</italic> PB6, and <italic>B. subtilis</italic> DSM32315 with a dosage of 1 × 10<sup>9</sup> cfu/kg, respectively. The experiment lasted for 42 days. The compositions and diversity of jejunal microflora were analyzed by MiSeq high-throughput sequencing. The <italic>B. coagulans</italic> TBC169 group showed marked improvements of growth performance, nutrient digestibility and intestinal morphology compared with the other <italic>B. subtilis</italic> treatments. <italic>B. coagulans</italic> TBC169 supplementation improved the average body weight (BW), average daily weight gain (ADG), total tract apparent digestibility of crude protein and gross energy (GE), and reduced feed conversion rate (FCR) compared with the control group (<italic>P</italic> &lt; 0.05). The villus height to crypt depth ratio (VH/CD) of jejunum and duodenum was increased in the birds fed with <italic>B. coagulans</italic> TBC169 compared with the control group (<italic>P</italic> &lt; 0.05). However, two <italic>B. subtilis</italic> treatments presented more positive variation of the jejunum microflora of chickens than that in the <italic>B. coagulans</italic> TBC169 group. <italic>B. subtilis</italic> PB6 and <italic>B. subtilis</italic> DSM32315 treatments improved the diversity of jejunal microbiota on day 21 compared with the control (<italic>P</italic> &lt; 0.05), while which were decreased on day 42 (<italic>P</italic> &lt; 0.05). The supplementation with <italic>B. coagulans</italic> TBC169 significantly improved the proportion of Firmicutes, otherwise two <italic>B. subtilis</italic> significantly improved the proportion of Proteobacteria, Bacteroidetes, Actinobacteria, and Acidobacteria at the phylum level during starter phase and decreased the proportion of Bacteroidetes during growing phase compared with the control. The supplementation with <italic>B.subtilis</italic> DSM32315 significantly improved the proportion of Clostridiales during starter phase, whereas two <italic>B. subtilis</italic> significantly improved the proportion of <italic>Pseudomonas, Burkholderia, Prevotella, DA101</italic> during growing phase at the genus level compared with the control. In conclusion, the dietary supplementation with probiotic <italic>Bacillus</italic> spp. strains improved body weight and intestinal morphology in broiler chickens, which might be associated with the gut microbiota.</p>