Indigenous probiotics Lactobacillus reuteri and Enterococcus faecium exhibit positive growth performance and disease prevention against extended-spectrum cephalosporin and fluoroquinolones resistant Salmonella enterica in broiler chicks.

ABSTRACTThe rapid increase in antibiotic resistance poses a global threat to public health, necessitating the development of effective antimicrobial alternatives. This study compared an indigenous probiotic mix containing Lactobacillus reuteri and two strains of Enterococcus faecium to a commercial probiotic blend ProtexinR on the growth performance, mortality rate, histomorphology, serum immunoglobulins, and intestinal microflora of broiler chickens challenged with two multi drug resistant Salmonella serovars, Typhimurium and Enteritidis. Two hundred and forty day-old broiler chicks were randomly assigned to six treatment groups for 4 weeks: the treatment groups were; birds continuously supplemented with only indigenous probiotic strains (108 CFU/mL) (IPRO-); birds challenged with Salmonella serovars 106 (CFU/mL) (PC+); birds continuously supplemented with indigenous probiotic strains and challenged with Salmonella serovars (IPRO+); birds supplemented with ProtexinR and challenged with Salmonella serovars (CM+); birds supplemented with only ProtexinR (CM-); and birds with no Salmonella challenge or probiotics (negative control; PC-). The results revealed that IPRO- diets significantly improved feed conversion ratio (FCR) and increased body weight (BW) (P [≤] 0.05). No effect of probiotic treatments was observed on IPRO- and CM- on relative organ weights as compared to the negative control (PC-). The Salmonella- challenged group PC+ had the highest (20%) mortality rate and lowest BW. The IPRO- had significantly lower FCR (1.55) compared to PC- (1.86) and PC+ (1.95). The broilers in the IPRO- group showed significantly increased serum concentrations of IgA and IgG relative to both control groups (P [≤] 0.05). Morphological analysis of the ileum revealed significant increases (P [≤] 0.05) in the villus height and villus height/crypt depth in birds fed IPRO- compared with the PC+. Cecal Lactobacillus and Enterococcus counts were the highest (P [≤] 0.05) and Salmonella counts were the lowest (P [≤] 0.05) in the IPRO- group compared to the Salmonella infected group PC+. These results indicated that indigenous probiotic strains Lactobacillus reuteri and Enterococcus faecium can be an effective and low-cost alternative compared to commercial probiotics in the Pakistan poultry industry.