Effect of fibrous diet and vitamin C inclusion on uniformity, carcass traits, skeletal strength, and behavior of broiler breeder pullets

Abstract

This experiment studied the effect of broiler breeder nutritional strategies on uniformity, carcass traits, tibia parameters, and behavior during rearing and prebreeder periods (up to 22 wk of age). One-day-old pullets (n 5 384) were randomly assigned to 4 treatments arranged as a 2!2 factorial,with 2 fiber levels (control vs. fibrous diet, 15% diluted in AMEn and nutrient content) and 2 vitaminCfeed inclusions (0 vs. 200 mg/kg).At 6, 15, and 22 wk, blood sampling was carried out (4 birds/replicate) to determine serum alkaline phosphatase (ALP) levels, and behavior was observed by visual scan sampling. At 22 wk, carcass traits, tibia parameters, and intestinal morphology were assessed (2 birds/replicate), and tail- and wing-feather integrity of all birds were scored. Fibrous diet did not modify BW uniformity, mortality, or tibia growth when compared with control diet. Pullets fed the fibrous diet had lower tibia breaking strength, elasticmodulus, and ash content values (P , 0.05). They also had lower ALP serum level at 6 and 22 wk (P , 0.05), their breast muscle was less developed (18.5 vs. 19.8%, P , 0.05), and their abdominal fat deposition was higher (1.14 vs. 0.87%, P , 0.05). At 15 and 22 wk, they performed, on average, 97% less grasping feather pecking and 45% less non–food object pecking behaviors, and their wing-feather score was lower (P , 0.05) at 22 wk. Tail- and wing-feather scores of the control treatments were reduced by vitamin Cinclusion (tail: 0.30 vs. 1.15,P,0.05;wing: 0.98 vs. 1.26, P , 0.05) at 22 wk. In conclusion, fibrous diet improves carcass traits (reduces breast muscle and increases abdominal fat deposition), deteriorates bone mineral deposition and thus skeletal strength, and reduces stereotypic behaviors, improving wing-feather integrity. Vitamin C inclusion improves tail- and wing-feather integrity of lower in feed allowance.