Effect of Dietary Acidifier on Growth, Mortality, Post-Slaughter Parameters and Meat Composition of Broiler Chickens / Wpływ zakwaszacza diety na masę ciała, śmiertelność, wydajność rzeźną i skład mięsa kurcząt rzeźnych

An experiment with 608 broiler chickens was conducted to investigate the effect of dietary acidifier level on body weight, feed consumption and conversion, mortality, dressing percentage, postmortem carcass traits, tissue composition of breast and leg muscles, and plasma chemical parameters. Feeding the acidifier to chickens at 3, 6 and 9 g/kg of the diet reduced the pH of starter and grower diets from 6.90 to 5.89, and from 6.28 to 5.73, respectively. Compared to the control group, dietary acidification significantly increased body weight of chickens by 6.2, 8.2 and 8.2% at 21 days of age, and by 2.7, 3.6 and 3.7% at 42 days of age, respectively (P<0.01). Mortality decreased from 2.58% in the control group to 0.00-0.59% in the experimental groups (P<0.01). Acidification of the diets increased EEI-index from 327 (control group) to 348 points in the experimental group supplemented with 9% (9 g/kg) acidifier, but had no significant effect on feed consumption and feed conversion ratio among treatments. The relative weight of breast and leg muscles, gizzard, liver and carcass depot fat was not affected by dietary treatments. Breast muscles represented 27.7% (control group) and 27.9% (experimental groups) of the carcass weight. Leg muscles made up 21.5% and 20.7% of the carcass weight, respectively. There were no significant differences in chemical composition of breast and leg muscles, including dry matter, protein and fat content. No significant differences between the control and experimental chickens were noted for determined blood plasma constituents, glucose, total protein, triglycerides, total cholesterol and high density lipoprotein. The results suggested that organic acid acidifier used in this experiment at the rates of 3 to 9 g/kg diet has a growth enhancing and mortality reducing effect in broiler chickens, with no significant influence on carcass yield, proportion of individual carcass parts and blood plasma constituents. It seems that the amount of 6g of the applied acidifier per kilogram of feed may be recommended as the optimum dietary level if protein in the diet does not exceed 200-230 g crude protein per kilogram of diet.