عنوان مقاله [English]
نویسندگان [English]چکیده [English]
This study was conducted to determine the effects of four different dietary levels of fish oil on performance, fatty acids composition, cholesterol and triglyceride in liver, breast and thigh muscle of broiler chicks. Two hundred and forty d-old male broiler chicks in a completely randomized design were allotted with four replicates. Broilers were fed isonitrogenous and isoenergetic diets containing 0, 1, 2 and 3% fish oil levels (treatments 1, 2, 3 and 4 respectively) ad-libitum in both starter (11 to 21 d) and growth periods. During the final week of the experiment (42 to 49 d) fish oil was removed from the diets. All of experimental groups were fed with the same diet to 10 d-old. The body weight gain, as well as feed efficiency were higher in broilers fed with fish oil as compared with control. The differences in feed intake were not significant. The fatty acid profiles in tissues were altered by fish oil. The effects of different levels of FO were not significant on cholesterol and triglyceride, except for the concentration of cholesterol in liver (p<0.05), that was lowered with 3% FO, but after withdrawal of FO from diet (49 days of age) the concentration of cholesterol and triglyceride significantly decreased in thigh and liver samples (p<0.05). Increased levels of fish oil clearly increased the amount of ?-3 and ?-6 polyunsaturated fatty acids in liver, breast an thigh muscle (p>0.05), and increased ?-6 linoleic acid only at 42 days of age which was significant in liver tissue. In conclusion, the addition of FO in diet up to 2-3% and removing of FO during the last week and before slaughtering of the birds can be used for enrichment of meat.