饲料n-3 HUFA水平对三疣梭子蟹(Portunus trituberculatus)幼蟹生长、饲料利用和组织脂肪酸组成影响的研究

Effects of dietary n-3 HUFA levels on growth performance, feed utilization and tissue fatty acid composition of juvenile swimming crab(Portunus trituberculatus)

以白鱼粉和酪蛋白为蛋白源,通过调节EPA和DHA高浓度油来配制四组等氮（42.00%~44.10%）、等能（18.26~18.67 k J/g）含有4种不同n-3高不饱和脂肪酸（n-3 HUFA）水平（0.52%、1.12%、2.33%和4.02%）的试验饲料,每组饲料设3个平行,每个平行15只螃蟹,进行为期8周的摄食生长实验。实验结果表明,饲料中不同n-3 HUFA水平影响了三疣梭子蟹的增重率,2.33%组显著高于0.52%组和4.02%组（P〈0.05）。随着实验饲料中n-3 HUFA水平的上升,饵料系数（FCR）呈现出先下降后上升的趋势,最低值出现在2.33%组,为1.02±0.11,显著低于0.52%组和4.02%组（P〈0.05）。肝体比（HSI）随着实验饲料中n-3 HUFA水平的上升而下降,其中4.02%组显著低于0.52%组（P〈0.05）。三疣梭子蟹肌肉和肝胰腺的脂肪酸组成明显受到了饲料脂肪酸组成的影响,肌肉和肝胰腺脂肪酸中n-3 HUFA含量与饲料脂肪酸中n-3 HUFA含量呈现正相关关系。综合饲料n-3 HUFA含量对其生长和饲料利用的影响,再结合生长的折线模型,估算出三疣梭子蟹配合饲料中n-3 HUFA的适宜添加量为2.36%。

Four isonitrogenous and isoenergetic experimental diets were formulated to contain four n-3 HUFA levels（0.52%, 1.12%, 2.35%, and 4.02%）. White fishmeal and casein were used as protein sources. And DHA and EPA enriched oil were used for adjusting the n-3 HUFA levels. There were three replicates （15 crabs per replicate） for each diet treatment. The crabs were fed （about 6%-8% body weight） twice daily for 8 weeks. WG of swimming crab was significantly affected by dietalw n-3 HUFA （P〈0.05）, WG of 2.33% group was significantly higher than 0.52% and 4.02% group（P〈0.05）. As the increasing of dietary n-3 HUFA levels, FCR declined and then increased. The lowest value ap- pear in 2.33% group, and it was significant lower than 0.52% and 4.02% group （P〈0.05）. HSI de- creased as the increasing of dietary n-3 HUFA levels, and the value of 4.02% group was significantly lower than 0.52% group （P〈O.05）. There was a positive correlation between tissue and dietary n-3 HU- FA content. Based on WG, the requirement for n-3 HUFA of juvenile swimming crab is about 2.36% of dry diet by broken-line analysis.