Abdominal fat deposition and fatty acid synthesis are lower and beta-oxidation is higher in broiler chickens fed diets containing unsatuarated ratherthan saturated fat

We evaluated the effects of dietary fat type on fat metabolism and depositi on in broiler chickens. Birds were fed diets containing either 8 g dietary saturated (beef tallow) or polyunsaturated fat (sunflower oil)/100 g for 32 d, The abdominal fat deposition of chickens fed the sunflower oil-enriched diet was significantly lower than that of chickens fed the tallow-enriched diet (2.63 +/- 0.47 versus 3.03 +/- 0.44 g/100 g live wt.; P = 0.033). The specific activities of heart carnitine palmitoyltransferase I and L-3-hydr oxyacyl-CoA dehydrogenase were higher (P less than or equal to 0.03) in chi ckens fed the sunflower oil-enriched diets, indicating a greater rate of be ta -oxidation, Liver fatty acid synthetase activity was lower (P = 0.01) in chickens fed the sunflower oil-enriched diet, suggesting reduced hepatic l ipogenesis in this group. Postprandial plasma triglyceride levels were sign ificantly lower (P < 0.05) in birds fed the sunflower oil-enriched diet, in dicating a higher rate of dietary lipid clearance from the bloodstream to t issues. In conclusion, the lower fat deposition observed in broilers fed su nflower oil-enriched diets appears to be the net result of an increased rat e of lipid catabolism and lower rate of fatty acid synthesis despite higher dietary fat absorption.