Effect of Intensity and Duration of Quantitative Feed Restriction and Dietary Coenzyme Q10 on Growth Performance, Carcass Characteristics, Blood Constitutes, Thyroid Hormones, Microbiota, Immunity, and Ascites Syndrome in Broiler Chickens

This experiment was conducted to investigate the effects of feed restriction and dietary supplementation of coenzyme Q10 (CoQ10) on growth performance, carcass characteristics, blood parameters, hormonal, immune responses, and intestinal microbiota. The completely randomized design experiment used a 2×2×3 factorial arrangement of treatments to provide two dietary restriction levels (10 and 20% less than the standard guide for Ross strain 308 broilers), two restriction durations (7 and 14 days), and three levels of CoQ10 (0, 20, and 40 mg/kg). In addition to the above-mentioned treatments, 3 other treatments were provided without feed restriction for each of the 3 levels CoQ10. Each of the fifteen treatments was replicated 4 times with each replicate containing 10 male birds. No differences were observed in weight gain among treatments. Feed conversion ratio decreased significantly when chicks had the highest duration (14 days) and intensity (20%) of feed restriction and fed all 3 levels of coQ10 as well as when had the mild duration (7 days) and intensity (10%) of feed restriction without coQ10 supplementation (P < 0.05). Heart weight and right ventricular to total ventricular ratio were not affected by feed restriction, but both total heart and right ventricular ratio decreased when CoQ10 was fed (P < 0.05). Blood and hormonal parameters were relatively unaffected by treatments although cortisol decreased with CoQ10 supplementation and CoQ10 at 40 mg/kg increased immune globulins M and G (P < 0.05). Under the conditions of this experiment, we conclude that supplementing CoQ10 can partially overcome the negative effects of feed restriction. Although the exact mechanism is unknown, CoQ10 appears to improve immune response and reduce subclinical ascites syndrome.