Effect of feeding different levels of dietary vermi-humus on growth performance and meat quality in broiler chickens

In order to evaluate the effect of feeding different levels of vermi-humus supplement (as a source of humic acid) on the performance of broiler chickens an experiment was conducted using 240 broiler chickens (Ross 308) in a completely randomized design by four treatments (vermi-humus levels of 0, 0.5, 1 and 1.5 percent) and five replicates of 12 chickens per each for 42 day. The experimental treatments had no significant effect on the growth performance, carcass percentage, internal organs weights, serum concentrations of calcium and phosphorus and tibia bone ash. Increasing the levels of vermi-humus up to one percent of diet resulted in linear decline in pH of breast meat (P<0.05), although the level of 1.5 percent increased the pH value. The thigh meat pH increased at 1 and 1.5 percent levels of vermi-humus supplementation in diet compared to control and 0.5 percent groups. The concentration of malon dialdehyde of fresh and preserved thigh meat decreased linearly with increasing the levels of vermi-humus supplementation in diet, while the malon dialdehyde of breast meat changed in quadratic manner (P<0.01). Water holding capacity of meat increased linearly with enhancement of level of vermi-humus supplement in the diet (P<0.01). Addition of vermi-humus at the level of one percent in diet leads to improvements in the color, smell, juiciness and overall acceptance of breast meat compared to the control (P<0.05), but these parameters had not affected in thigh meat. The results showed that feeding vermi-humus up to one percent of diet could improve the breast meat quality, taste and flavor without adverse effect on performance.