The effect of dietary humic substances on the fattening performance, carcass yield, blood biochemistry parameters and bone mineral profile of broiler chickens

Abstract

Humic substances are currently being considered as a new feed component in replacement of antibiotic growth stimulators to improve growth and health in animals. The aim of our work was to evaluate the effect of the addition of humic substances to the feed at concentrations of 0.8% and 1.0% on the growth parameters, carcass yield, selected blood enzymes, minerals, and the bone quality in broiler chickens. One hundred fifty COBB 500 one-day-old male broiler chicks were randomly divided into one control and two experimental groups (n = 50) with three replications (16, 16 and 17 per pen), and fattened for 35 days. The broilers of the experimental groups (H0.8 and H1.0) were fed commercial feed mixtures with added humic substances (at 8 g·kg-1and 10 g·kg-1). The control group was fed a diet without the addition of humic substances. A slight increase in the final body weight and feed conversion ratio was noted in the experimental groups (P> 0.05). Significantly higher yields of breast and thigh meat (P< 0.05) were recorded for the experimental group H1.0. The blood cholesterol level was lower for both experimental groups. A lower concentration of alkaline-phosphatase was observed in group H1.0. A decrease in aspartate aminotransferase and calcium was recorded for group H0.8. A significantly higher content of calcium and lower content of phosphorus was found in the bones of experimental animals. The 1% addition of humic substances had a positive impact on growth parameters (P> 0.05), improved selected blood indices and increased the calcium content in the bones of broilers (P< 0.05).