Effect of Humic Substance Supplementation on Performance and Gut Health in Broilers

The study was conducted to investigate the effect of dietary supplementation of humic substance (HS) on performance of broilers. 120 day old broiler chicks were randomly distributed into 6 dietary treatments with five replicates of four chicks each. Broiler diets were formulated as per commercial chick feed specification (2011). Antibiotic growth promoters (AGP) group diet was same as CON with addition of AGP whereas, in HS0.1, HS0.2, HS0.3 and HS0.4 replacing antibiotic with HS @ 1, 2, 3 and 4 g/kg feed, respectively. Individual body weight and feed intake were recorded and thus feed to gain ratio and European production efficiency index (EPEI) % was calculated. Birds were sacrificed to estimate carcass traits, intestinal histomorphometry and caecal microbial count. Immunological response and liver function tests (SGOT and SGPT) were estimated. Broiler performance (0-6 weeks) indicate that supplementation of HS0.4 significantly (p<0.05) improved body weight. Better feed to gain ratio and EPEI % was observed with HS0.2 compared to CON. Crude protein and crude fat utilization improved significantly (p<0.05) in broilers fed with HS0.2 and HS0.4. Supplementation of HS significantly (p<0.05) improved intestine villus height (VH), crypt depth (CP) and VH:CD ratio. Caecal E. coli count was lowered, humoral immune response, weight of bursa of fabricius, spleen, serum IgG and IL-10 levels were increased in HS supplemented groups compared to CON. HS inclusion had no effect on the carcass traits, nutrient composition of meat and liver function tests. Lower feed cost per kg weight gain and improved economic efficiency was observed in broilers fed on diets supplemented with HS0.2. It can be concluded that supplementation of HS0.2 in feed can be used as an economically efficient alternative to antibiotic growth promoters in broilers diet.