Effects of dietary conjugated linoleic acid, fish oil and soybean oil on body-fat deposition and serum lipid fractions in broiler chickens
An experiment was conducted on broiler chickens to study the effects of dietary fats rich in conjugated linoleic acid (CLA), fish oil (n-3 rich oil), soybean oil (n-6 rich oil), polyunsaturated fatty acids (PUFAs) alone or in dual mixtures, as well as palm oil as a more saturated fat on tissue fat deposition and serum lipid concentrations of broiler chickens. The fat included in the experiment's diets is a dose of 7% for single fats and 3.5 + 3.5% for the dual mixtures. The conjugate linoleic acid (CLA) supplement used in this study was LUTA-CLA 60, containing 60% CLA, so that dietary inclusion of 7 and 3.5% LUTA-CLA 60 were supplied with 4.2 and 2.1% CLA, respectively. The chickens fed diets containing palm oil, soybean oil or fish oil as the only dietary fat deposited more fat in breast tissue compared with other groups (P < 0.05). The highest fat in thigh tissue was observed in birds fed 7% fish oil (P < 0.05). The CLA containing diets resulted in fatter liver tissue (P < 0.05). The diets containing 7% fish oil effectively decreased the lipid content of chicken's liver (P < 0.05). The fish oil and soybean oil as n-3 and n-6 rich sources, respectively demonstrated a comparable reduction in the serum cholesterol and low density lipoprotein (LDL) concentrations (P < 0.05), while the 7% CLA diet increased serum high density lipoprotein (HDL) level (P < 0.05). The results of this study showed that dietary fish oil, and CLA effectively increased fat content of meat and liver tissues, respectively; and the dietary soybean oil and fish oil were more effective on reducing serum undesired lipoproteins, as compared with CLA.
Key words: CLA, PUFA, body fat deposition, serum lipids and broiler chickens.