Preventive antimicrobial action and tissue architecture ameliorations of in challenged broilers.

BACKGROUND AND AIM

Probiotics improve intestinal balance through bacterial antagonism and competitive exclusion. This study aimed to investigate the o antimicrobial activity, as well as the o preventive, immunological, productive, and histopathological modifications produced by probiotic s.

MATERIALS AND METHODS

The antimicrobial activities of (5×10 CFU/g; 0.5, 1.0*, 1.5, and 2.0 g/L) were tested against O157: H7, Typhimurium, , and after exposure times of 0.25, 0.5, 1, and 2 h using minimal inhibitory concentration procedures. A total of 320 1-day-old female Ross broiler chickens were divided into five groups. Four out of the five groups were supplemented with 0.5, 1.0*, 1.5, and 2.0 g/L probiotic from the age of 1 day old. Supplemented 14-day-old broiler chickens were challenged with only O157: H7 (4.5×10 CFU/mL) and . Typhimurium (1.2×10 CFU/mL). A total of 2461 samples (256 microbial-probiotic mixtures, 315 sera, 315 duodenal swabs, and 1575 organs) were collected.

RESULTS

The results revealed highly significant (p<0.001) killing rates at all-time points in 2.0 g/L : 99.9%, 90.0%, 95.6%, and 98.8% against , . Typhimurium, , and , respectively. Broilers supplemented with 1.5 and 2.0 g/L revealed highly significant increases (p<0.01) in body weights, weight gains, carcass weights, edible organs' weights, immune organs' weights, biochemical profile, and immunoglobulin concentrations, as well as highly significant declines (p<0.01) in total bacterial, , and counts. Histopathological photomicrographs revealed pronounced improvements and near-normal pictures of the livers and hearts of broilers with lymphoid hyperplasia in the bursa of Fabricius, thymus, and spleen after supplementation with 2.0 g/L .

CONCLUSION

The studies revealed that 1.5-2.0 g of probiotic at a concentration of 5×10 CFU/g/L water was able to improve performance, enhance immunity, and tissue architecture, and produce direct antimicrobial actions.