Effects of dietary conjugated linoleic acid on the growth performance of chickens and ducks for fattening and fatty acid composition of breast meat
The effects of dietary conjugated linoleic acid (CLA) supplementation on feed intake, growth performance, carcass composition and fatty acid composition of meat tissue were investigated in broiler chickens and Pekin ducks. A total of 108 male chickens for fattening and a total of 96 male and 96 female Pekin ducks were allocated to 3 dietary treatments (0.0, 0.1 and 0.2 % CLA) and fed for 35 or 49 days. The results showed that 0.2 % CLA supplementation in the first 3 weeks improved the daily feed intake of the broilers and the feed to gain ratio, but did not significantly influence body weight, weight and the percentage of abdominal and visceral fat as well as the intramuscular fat in breast muscles. In the duck trial, the daily feed intake was significantly higher through the first 3 weeks of male control group and male 2 g CLA group compared with the female control group. The daily weight gain of all male ducks was significantly higher compared to female ducks of all groups and was not influenced by the CLA supplementation. The feed to gain ratio of the 1 g CLA-male ducks was lowest compared to male and female control ducks and 1 and 2 g CLA female ducks. Supplementing diets with CLA modified the fatty acid composition of breast muscle. The proportion of CLA was increased in broiler meat. In duck meat, the proportions of CLA, saturated fatty acids and polyunsaturated fatty acids were increased and monounsaturated fatty acids were decreased.