Dietary fat type, body composition and fatty acid metabolism in broiler chickens

Abstract

An increased intake of PUFA in the form of soybean oil at the expense of SFA in the form of tallow reduced abdominal deposition by broiler chickens in a does-dependent fashion, the relationship being essentially independent of the fat level of the diet. Dietary fats rich in MCT would diminish abdominal fat deposition as do fats rich in PUFA. Broiler chickens were fed on diets containing either tallow, which is rich in SFA, soybean oil, which is rich in PUFA, or krabok oil, which is rich in MCT. In the dietary soybean oil versus tallow significantly lowered abdominal fat deposition. The feeding of krabok oil instead of tallow did not affect the weight of abdominal fat. PUFA instead of SFA was found that amount of body fat was reduced significantly when about 75 % of the tallow was replaced by soybean oil. Energy expenditure trended to increase in soybean oil diet. Also inhibit whole-body de novo fatty acid synthesis. As indexes of de novo fatty acid synthesis, the concentration of plasma triacylglycerols and minimum fatty acid synthesis. It was found that the level of plasma triacylglycerols was decreased, but it was not associated with minimum de novo fatty acid synthesis in the whole body. Energy expenditure of broilers fed the high-PUFA diet tended to be higher were fed restricted or ad libitum feeding. In the birds fed the diet with PUFA instead of SFA, the deposition:intake ratio was raised for SFA, but diminished for mono-unsaturated fatty acids (MUFA). The increased deposition:intake ratio for SFA may be explained by an enhanced de novo synthesis of SFA, whereas the decreased ratio for MUFA was associated with a diminished synthesis of MUFA. The decreased ratio of deposition:intake for PUFA in the birds fed the high-PUFA diet may be explained by preferential oxidation of PUFA. The diet containing ALA instead of LA would alter the whole body fatty acid metabolism and deposition and energy expenditure. Soybean oil was used as LA source and linseed oil was used as ALA source. The high-LA and high-ALA diets had no differential effect on energy balance, but the amount of fat in the whole carcass was decreased in the birds fed the high-ALA diet. The rate of whole body de novo synthesis of monounsaturated fatty acids was higher in chickens fed the high LA-diet than in their counterparts fed the high ALA-diet. Birds fed the high-ALA diet tended to have less abdominal fat when compared with birds fed the high LA-diet. In the last study, the experimental diets were enriched with linseed oil as source of ALA and contained either beef tallow as source of SFA or sunflower oil as source of PUFA. The broilers fed the PUFA diet tended to have higher values for energy expenditure and lower values for whole body fat content. In general, it is concluded that the feeding of PUFA versus SFA lowers the amount of abdominal fat in broiler chickens through preferential oxidation of PUFA.