Effects Of Bacillus Subtilis DSM32315 Supplementation In Low Crude Protein Diet On Growth Performance And Gut Health In Weaned Piglets

Early weaning is critical event in piglets,frequently associated with insufficient intestinal development,gut microbiota dysbiosis,which result in serious health and nutritional disorder such as reduction of nutrient digestibility and diarrhea.This situation may be more severe when piglets are fed with high-level crude protein diet.Low crude protein diet(LP)or / and supplementation of probiotics may be beneficial to gut health and improve growth performance of piglets.The study investigated the effects of Bacillus subtilis DSM32315(Bas)and different crude protein levels on growth performance and intestinal health of weaned piglets,and evaluate the efficacy of Bas at low crude protein diet for weaned pigs.The finding may provide a potential nutritional strategy to improve performance and gut health of piglets.72 piglets ‘Duroc×Landrace×Yorkshine’ aged at 25 days were allotted to 4 treatment groups in a randomized complete block design involving a 2(two protein levels)×2(two added probiotic levels)factorial arrangement of treatments in a 42-d trial.Two protein levels included HP(0-14 d,20.5%;15-42 d,19.5%)and LP(0-14 d,18%;15-42 d,17%),and added probiotic levels included 0 and 500 mg/kg diet.The results were as follows:(1)Compared with HP diet,The growth performance,the apparent total tract digestibility,luminal morphology and gut microbiota were not affected in pigs fed LP diet.But The colonic digesta p H was increased(P<0.05)in pigs fed HP diets compared with pigs fed LP diets,and BUN was decreased(P<0.05)in pigs fed LP diets compared with HP diet.(2)Pigs fed diets containing Bas had greater(P<0.05)ADG and lower F/G than pigs fed diets without Bas.The ATTD of CP(P<0.01),DM(P<0.05),EE(P<0.01)were increased in pigs fed diets containing Bas compared with pigs fed no Bas.Pigs fed with Bas had greater(P<0.01)villus height and villus height: crypt depth ratio in jejunum and ileum.The VFA contents of cecum and colon digesta were greater(P<0.05)in pigs fed diets containing Bas compared with pigs fed no Bas.The populations of Bacillus,Bifidobacterium(P<0.05),and Lactobacillus(P<0.05)of Bas groups were increased.The m RNA expressions of ileal mucous ZO-1,Occluding-1,IGF-1R and EGF in Bas groups were greater(P<0.05)than other groups(3)The apparent total tract digestibility of CP(P<0.01)and EE(P<0.05)were increased in pigs fed the LP diet containing Bas compared with other treatments.Piglets fed the LP diet plus Bas had greater villus height and villus height: crypt depth ratio of ileum than the other treatments.Piglets fed the LP diet plus Bas had greater villus height of jejunum(P <0.05).Piglets fed with the LP diet plus probiotic had greater population of Bifidobacterium and Bacillus in colonic content than other treatments(P<0.05).The acetic acid of ileal digesta was greater for pigs fed the LP diet containing Bas compared with other treatments.There were interactions between CP and Bas for the m RNA expressions of ileal Occludin-1,EGF,and IGF-1R,and piglets fed with LP diet plus Bas had greater EGF and IGF-1R m RNA expressions than other treatments.These results suggested that 2.5% reduction of dietary protein levels in piglets’ diets has no significant effect on growth performance,but the supplementation of 500 mg/kg Bas can increase the apparent total tract digestibility,improve the intestinal morphology,increase the abundance of beneficial bacteria in digesta,and increase the m RNA expression of tract developmental function,which result in improvement of the growth performance of weaned piglets.Furthermore,the LP diet worked synergically with the Bas to improve growth performance and gut health,and combined use of them show better effects than individual.