GROWTH-RESPONSE AND FATTY-ACID COMPOSITION OF JUVENILE PENAEUS-VANNAMEI FED DIFFERENT SOURCES OF DIETARY-LIPID

A study was conducted to evaluate the effects of feeding various sourc es of dietary lipid on weight gain, feed conversion, survival and fatt y acid composition of juvenile Penaeus vannamei. Seven semi-purified d iets (35% protein and 3400 kcal of metabolizable energy kg(-1)) contai ning defatted, freeze-dried shrimp meal, 1.0% soybean lecithin and 0.5 % cholesterol were supplemented with 6.5% of either stearic acid, coco nut, safflower, corn, soybean, linseed or menhaden fish oils. Each die t was fed to shrimp (1.00 +/- 0.03 g average weight) in four replicate aquaria four times daily for 10 weeks. Weight gain, feed conversion a nd survival were best for shrimp fed the diet containing menhaden fish oil. Shrimp fed the linseed oil diet had the second highest weight ga in, followed by shrimp on soybean oil, corn oil, stearic acid, coconut oil and safflower oil diets, respectively. Feed conversion values wer e a reflection of weight gain. Results of this study show that both n- 6 and n-3 fatty acids are dietary essential for juvenile Penaeus vanna mei, although n-3 fatty acids promoted faster growth than n-6. However , highly unsaturated fatty acids (HUFA) (20:5n-3 and 22:6n-3) had bett er growth-promoting effect than 18:3n-3, due probably to the limited a bility of shrimp to bioconvert fatty acids to polyenoic forms of longe r chain length. The fatty acid composition of the shrimp generally ref lected that of the dietary lipids, especially for the diets containing unsaturated fatty acids. Shrimp fed stearic acid and coconut oil diet s low in polyunsaturated fatty acids accumulated high levels of 16:1n- 7 and 18:1n-9. Published by Elsevier Science B.V.