亞麻油酸(Linoleic Acid)及次亞麻油酸(Linolenic Acid)封奧利亞吳郭魚(Oreochromis Aureus)之生長、耐寒性及極性脂質組成的影響

The effect of linoleic acid (C18:2ω6) and linolenic acid (C18:3ω3) on the growth, cold tolerance and the composition of polar lipid of Oreochromis aureus were studied. The diets were prepared by adding both linoleic acid (C18:2ω6) and linolenic acid (C18:3ω3) at different proportions. After ten-week experiment, the results indicated that the addition of linoleic acid or linolenic acid to the basal diet containing only lauric acid (C12:0) improved the weight gain and feed conversion efficiency. However, the growth-promoting effect of linleic acid was better than that of linolenic acid. Thediet requirement of linoleic acid was found to be around 1% of drp feed. During the following cold-tolerance test, the temperature was decreased 1℃ every two hours from 22℃ until it reached 6℃.It appears that the cold tolerance of Oreochromis aureus had no obvious relationship with types of dietary fatty acids. Feeding the fat-free diet or the diet containing only 5% lauric acid (C12:0) could elevate the proportion of ω9 fatty acids in the polar lipids of Oreochromis aureus bodies. This trend was lowered proprtionally by the supplementation of linoleic acid or linolenic acid, and the former appeared to be more efficient. In addition, the supplementation of linoleic acid to the diets caused the increase of the proportion of C20:4ω6 in the polar lipid composition of Oreochromis aureus while linolenic acid caused the increase of C22:6ω3 proportion.