Evaluation of different probiotic administration methods on productive performance, visceral organs, intestinal bacteria, and morphology in broiler chickens.

This study aimed to evaluate the effects of different probiotic administration methods on productive performance, intestinal health, and visceral organ development in broiler chickens. The study used 400 one-day-old unsexed Lohmann broiler chicks reared for 35 days and randomly allocated into 4 treatments and 5 replicates (20 birds per replicate) using a completely randomized design. The probiotics contained Lactobacillus sp. (2 × 107 CFU/mL), Bacillus sp. (1.6 × 107 CFU/mL), and Streptomyces sp. (7.4 × 109 CFU/mL). The probiotic administration methods included: untreated (control, T1), administered in drinking water (T2), sprayed onto the litter (T3), and administered through drinking water and sprayed onto the litter (T4). Probiotics were supplied at 2 mL/L of drinking water and 80 mL per pen (2 m × 1 m) for the spraying treatment. The results showed that compared to the control, probiotic administration (T2 and T4) improved (p < 0.05) body weight gain, feed intake, and decreased feed conversion ratio (FCR), water intake, mortality, and spleen weight. Intestinal health status improved (p < 0.05), as indicated by increased lactic acid bacteria populations and enhanced villus length, surface area, and crypt depth. Ileum weight (% BW) also increased in the probiotic group (p < 0.05), with no significant differences for other organs. T3 yielded higher jejunum and ileum length compared to the control group. It can be concluded that probiotic administration in drinking water is more effective than spraying it onto the litter in improving growth performance, intestinal development, beneficial intestinal microbiota, and intestinal morphology in broiler chickens.