EFFECTS OF DIETARY FATTY-ACIDS ON LIPOGENESIS AND LIPID TRAITS IN MUSCLE, ADIPOSE-TISSUE AND LIVER OF GROWING RABBITS

The effects of fat source on lipogenesis and lipid traits of longissim us muscle, liver and perirenal adipose tissue, weve studied in 48 New Zealand White rabbits, slaughtered at 11 or 15 weeks of age. Rabbits w ere offered diets with 20 g added fat per kg, containing either medium -chain (COC: coconut oil), saturated and monounsaturated (PAL: palm oi l) or polyunsaturated (SUN: sunflower oil) fatty acids as major compon ents. Diets did not affect growth performance, dressing proportion and tissue weights. Intramuscular lipid content was lower for COC than fo r SUN and PAL (e.g. 10 v. 13 and 12 g/kg, at 11 weeks, respectively, P < 0.05), whereas lipid content was unaffected by diet in liver and pe rirenal fat. In muscle, the fat source did not influence the activitie s of acetyl-CoA-carboxylase (CBX), malic enzyme (ME) and glucose-6-pho sphodehydrogennse (GGPDH). In liver, activities of G6PDH and ME were d epressed from the SUN diet, as compared with the COC or PAL diets. The diet-induced variations in enzyme activities in perirenal fat were lo wer than in the liver and were not significant. Medium-chain fatty aci ds were found only in tissue lipids of animals given COG. The ratio of polyunsaturated to saturated fatty acids decreased in the order SUN > PAL > COC in muscle and perirenal fat. Thus, polyunsaturated fat ty a cids exert an inhibition of G6PDH and ME activities specifically in li ver. Compared with COG, the addition of SUN to the basal diet increase d total lipids and polyunsaturated fatty acids contents in the longiss imus lumborum muscle, which might improve the organoleptic and dieteti c qualities of rabbit meat.