Dietary polyunsaturated fatty acids decrease fat deposition in separable fat depots but not in the remainder carcass

Abstract

Two experiments were conducted in order to determine the effect of dietary fatty acid profile on deposition of body fat, carcass fat, and separable fat depots. Diets with four types of fat (tallow, olive, sunflower, and linseed oils) at an inclusion level of 10% were administered to female broiler chickens. In Experiment 1, total body fat, carcass fat (total body fat minus abdominal fat), and abdominal fat (AF) were determined. In Experiment 2, several separable fat depots (abdominal, neck, sartorial, and mesenteric fat) were removed and weighed. In general, the analyzed separable fat depots were reduced in broilers fed sunflower or linseed oils with respect to those fed tallow or olive oil (P < 0.05). Percentages of body and carcass fat were also slightly reduced in birds fed sunflower or linseed oil, with respect to those fed tallow; however, the differences were not statistically significant. Regression analysis showed that body fat, carcass fat, and fat depots variability were closely correlated with AF (R2 = 0.69, 0.56, and 0.81, respectively), except for birds fed tallow, in which abdominal and mesenteric fat showed a different growth pattern with respect to the other treatments and to the other fat depots. These results suggest that polyunsaturated fatty acids reduce fat deposition in separable fat depots with respect to monounsaturated and saturated fats but not in the rest of the body fat depots. The growth pattern of fat depots can be modified by dietary fatty acid profile. Broilers fed saturated fat tend to deposit more fat in abdominal and mesenteric depots.