Effects of Rhodotorula mucilaginosa culture and Bacillus subtilis on diarrhea rate,nutrient apparent metabolic rate,and fecal ammonia emission in yellow-feathered broilers

GAO Aiqin; SU Xiangtan; WANG Ke; LU Xinyu; ZHANG Gaowei; YANG Guang

doi:10.13557/j.cnki.issn1002-2813.2025.21.010

Abstract：The experiment aimed to investigate the effects of Rhodotorula mucilaginosa culture(RYC)and Bacillus subtilis(BS)on the diarrhea rate,nutrient apparent metabolic rate,and fecal ammonia emission in yellow-feathered broilers.A total of 192 healthy yellow-feathered broilers aged one day and weighing(40.00±0.64)g were randomly divided into four groups,with six replicates per group and eight broilers per replicate.The control group(group CON)was fed a basal diet,while the experimental groups were supplemented with 0.005％BS(group BS),0.500％RYC(group RYC),and 0.005％BS+0.500％RYC(group MIX)in the basal diet,respectively.The test period lasted for 56 days,including the early stage(1 to 28 days)and the late stage(29 to 56 days).The results showed that compared with group CON,on day 28,the body weight of yellow-feathered broilers in group BS was significantly increased(P＜0.05).The apparent metabolic rate of crude protein(CP)was significantly increased in each experimental group(P＜0.05),and the apparent metabolic rate of crude fat(EE)was significantly increased in groups BS and RYC(P＜0.05),the apparent calcium(Ca)metabolism rate in the BS group was significantly increased(P＜0.05).On day 56,the apparent metabolic rates of CP and Ca were significantly increased in each experimental group(P＜0.05),and the apparent metabolic rate of EE was significantly increased in groups BS and RYC(P＜0.05).On day 28,ileal trypsin activity was significantly increased in groups BS and RYC(P＜0.05).On day 56,ileal α-amylase and trypsin activities were significantly increased in each experimental group(P＜0.05).On day 28,fecal ammonia emissions were significantly reduced in group BS at 24 hours and 48 hours of aerobic fermentation,in group RYC at 48 hours of fermentation,and in group MIX at 24,48,and 72 hours of fermentation(P＜0.05).No significant differences were observed in the diarrhea rate among each experimental group(P＞0.05).The study indicates that dietary supplementation with RYC and BS can effectively enhance digestive enzyme activity in the intestines,improve nutrient apparent metabolic rate,and significantly reduce fecal ammonia emissions in yellow-feathered broilers,but has no significant effect on the diarrhea rate.Among them,the joint application of RYC and BS has a better effect.