ABSTRACT
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.
Subject(s)
Abdominal Fat/drug effects , Body Composition/drug effects , Chickens/metabolism , Dietary Fats, Unsaturated/administration & dosage , Fatty Acids, Unsaturated/administration & dosage , Animal Feed , Animal Nutritional Physiological Phenomena , Animals , Body Composition/physiology , Dietary Fats, Unsaturated/metabolism , Dose-Response Relationship, Drug , Energy Intake/drug effects , Energy Intake/physiology , Fatty Acids, Unsaturated/metabolism , Female , Random AllocationABSTRACT
The effect of supplementation with different levels of all-rac-alpha-tocopheryl acetate and the inclusion of different dietary contents of PUFA on the deposition of alpha-tocopherol stereoisomers in liver and thigh of chickens was evaluated. Ninety-six 1-d-old Ross female broiler chickens were randomly distributed into eight experimental treatments (three replicates each) resulting from four levels of alpha-tocopheryl acetate without supplementation and supplemented with 100, 200 and 400 mg alpha-tocopheryl acetate/kg and two levels of dietary PUFA (15 and 61 g/kg). The feeds supplemented with alpha-tocopheryl acetate contained a similar proportion of each stereoisomer. The diets without alpha-tocopheryl acetate had the following alpha-tocopherol stereoisomers (%): RRR 35.1, RRS 24.5, RSR 25.3, RSS 13.9 and total 2S forms 1.3. Consumption of different levels of alpha-tocopheryl acetate did not lead to statistical differences in alpha-tocopherol stereoisomer proportion in the liver and thigh. In general, the stereoisomer profiles in the tissues studied were similar, responding to the stereoisomer profile of the diet. Both tissues preferentially accumulated 2R stereoisomer (69-100 %). However, when alpha-tocopheryl acetate was used the discrimination was not specific for the RRR alpha-tocopherol form. Furthermore, the 2R:2S ratio had a tendency to increase as the polyunsaturation level of the diet increased.
