Chemical composition and energy content of chickens in response to different levels of dietary polyunsaturated fatty acids.

Two experiments were performed to study the effect of dietary polyunsaturated fatty acids (PUFA) on abdominal fat pad weight and chemical composition of broilers. In Experiment 1, different fat sources were blended in different ratios keeping added fat level constant (9%). In Experiment 2, PUFA gradient was obtained by increasing the level of inclusion (2, 4, 6 and 8%) of PUFA-rich oil. The treatments had 15, 34, 45 and 61 and 28, 38, 48 and 59 g PUFA/kg diet, respectively. Apparent metabolizable energy intake was similar in both experiments, except for the more saturated diet in Experiment 1 (15 g PUFA/kg), where it was lower. In Experiment 1, abdominal fat pad weight, total body fat and body energy were lower in the animals on the high PUFA diets (p < 0.05) compared to the animals on the saturated-rich ones, meanwhile in Experiment 2 there were no differences on chemical and energy composition by increasing added PUFA-rich oil inclusion level. In conclusion, PUFA-rich chicken diets, compared to saturated-rich ones, cause a lower body fat deposition, but not compared to low-PUFA low-fat diets.