Effects of different dietary fat sources on performance and carcass characteristics of broilers

The effects of four different dietary fat sources on the performance, carcass characteristics, meat quality and fatty acid composition of abdominal fat of broilers were evaluated. As fat sources, a commercial animal/vegetable fat blend (Group 1), soybean oil (Group 2), rapeseed oil (Group 3) and a processed fat product (Group 4) were used. A total of 1300 one-day-old broiler chicks was assigned to 20 litter pens. Each dietary treatment consisted of five replicates (5 pens). The chicks were fed corn-soy-based all mash diets which contained 3.5% of the respective fat source for 43 days. The broilers which were fed the vegetable oils (Groups 2 and 3) performed better than those in Groups 1 and 4. Group 4 also excreted a higher amount of fat because of the decreased metabolizability of the saturated long-chain fatty-acids. The fatty acid composition of the fat excreted in the droppings confirmed that the saturated long-chain fatty-acids cannot be metabolized by young broiler chickens. The proportion of legs, breast meat and abdominal fat was not affected by the dietary treatment. There were no significant differences between the groups in dry matter, protein, and fat content of the thigh meat, or in organoleptic traits of the breast meat. The composition of the abdominal fat was typically influenced by the dietary fat source: the content of polyunsaturated fatty acids was significantly elevated in Group 2. Group 3 contained more oleic acid than any of the other groups, and in the abdominal fat of the broilers of Group 4 significantly higher contents of myristic acid, palmitic acid, palmitoleic acid, and behenic acid were found. It was concluded that the growth performance of broilers can be improved by incorporation of polyunsaturated fatty acids at levels higher than generally recommended without negative effects on quantitative carcass characteristics. However, the feeding of fats with a high percentage of saturated long-chain fatty-acids has a significant positive influence on the composition and the consistency of broilersʹ adipose tissue.