Effect of Bacillus subtilis, Clostridium butyricum and Lactobacillus acidophilus endospores on growth performance, nutrient digestibility, meat quality, relative organ weight, microbial shedding and excreta noxious gas emission in broilers

This study was conducted to evaluate the effects of Bacillus subtilis, Clostridium butyricum and Lactobacillus acidophilus (tri-strain probiotics, TSP) endospores in broilers. TSP can benefit the host animal by increasing nutrient absorption from the gastrointestinal tract and altering the intestinal ecosystem in poultry. A total of 500 day-old ROSS 308 mixed sex broiler chickens with an average initial body weight (IBW) of 45 g ± 0.6 g were used in this 35-day feeding study. Broiler chickens were randomly allotted to one of five dietary treatments: (1) CON (antibiotic free diet), (2) ANT1 (CON + enramycin 5 ppm), (3) ANT2 (CON + avilamycin 5 ppm), (4) TSP1 (CON + 0.1% TSP), and (5) TSP2 (CON + 0.2% TSP) with five replicates per treatment and 20 chicks per pen. Broiler chickens fed on TSP diets exhibited linearly increasing body weight gain (BWG) and decreased feed conversion ratio (FCR) compared to those on the CON diet (P < 0.05; Day 21 to Day 35 and Day 1 to Day 35, respectively). Further, dry matter (DM) and nitrogen (N) digestibility were improved (P < 0.05) in the TSP treatment at the end of study. The inclusion of TSP reduced (linear, P = 0.02) meat lightness (L*) compared with CON and ANT treatments. Broiler chickens fed with TSP diets had relatively higher (linear, P < 0.05) bursa weight than those fed with ANT and CON diets. The supplementation of TSP increased (P < 0.05) the ileal and caecal Lactobacillus count compared with CON and ANT diets. The ileal and caecal Escherichia coli and caecal Clostridium perfringens counts were reduced (P < 0.05) in the TSP2 group compared with the CON group. Broiler chickens fed with TSP diets exhibited increased (P < 0.05) caecal Bifidobacteria counts compared with CON and ANT diets. Excreta ammonia (NH3) gas emission was lower (P < 0.05) with the TSP treatment compared with the CON treatment. In conclusion, the supplementation of TSP improved growth performance, nutrient digestibility, meat quality, gut health and reduced noxious gas emission in broilers.