Bacillus amyloliquefaciens: Application in Poultry
Adding Bacillus amyloliquefaciens (Ba.) to poultry feed can promote the absorption of nutrients, significantly increase feed conversion rate and body weight gain. Lei et al. added 30 mg/kg or 60 mg/kg of Ba. to the diet of 1-day-old AA broiler chickens, and tested their growth performance, nutrient utilization efficiency, small intestine morphology, and cecal microbiota at 21 and 42 days, respectively. The results showed that compared with the blank control group, at 21 days, the villus height and crypt depth of the duodenum, jejunum, and ileum of chickens fed with Ba. significantly increased; At 21 and 42 days, the number of Escherichia coli in the cecum significantly decreased; Compared with the control group and the erythromycin group, the number of lactic acid bacteria significantly increased; At 42 days, the Bacillus amyloliquefaciens group gained more weight and had a higher feed conversion rate. Adding Ba. to a plant-based diet can be an option for feeding broiler chickens.
When adding Bacillus amyloliquefaciens isolated from soybean paste to broiler feed, it was found that after 28 days of feeding, the live weight increased by 7% to 8% compared to the control group, and the feed conversion rate increased by 5.3% to 8.8%. Feeding broiler chickens with feed containing 15% fermented rice bran (FRB) with Ba. can increase their body weight and feed conversion rate without increasing feed consumption, with significant differences compared to the unfermented group. It is found that adding Bacillus amyloliquefaciens to the diet can significantly increase the average daily weight gain of broiler chickens and reduce the feed gain ratio of broiler chickens aged 1-21 days; Significantly increased the weight corrected length of the ileum in 28 day old broiler chickens, significantly increased the relative intestinal weight of the small intestine in 14- and 28 day old broiler chickens, and significantly increased the villus height of the ileum in 14-, 21-, and 28 day old broiler chickens; Increase the total protein content in the serum of 42 day old broiler chickens, and increase the levels of IgG and IgM in the serum of 7 and 21 day old broiler chickens.
Ba. can also alleviate the reduced dietary intake, decreased daily weight gain, increased feed conversion rate, increased spleen and bursa weight, and increased white blood cell count caused by LPS. It can also increase the concentration of lysozyme in plasma and reduce the degree of IL-2 and IL-6 increase caused by LPS, indicating that Ba. can alleviate the immune stress phenomenon caused by LPS in early growth of broiler chickens.
However, in the study by Ierzsele et al., it was found that Bacillus amyloliquefaciens (109 CFU/g) had no beneficial effect on necrotic enteritis caused by Clostridium perfringens in broiler chickens, as analyzed from aspects such as body weight gain, pathology, histological score, villus length, and villus length to crypt depth ratio; Geerarrs et al.'s study also demonstrated that although Bacillus amyloliquefaciens can significantly inhibit Clostridium perfringens in vitro, in vivo experiments have shown that it has no therapeutic effect on necrotizing enteritis.
