鲈鱼(Lateolabrax japonicus)养殖中期对饲料硒的需求量

The Requirement of Dietary Selenium at the Middle Growth Stage of Japanese Seabass (Lateolabrax japonicus)

中文关键词: 硒  鲈鱼  营养需求  生长中期

英文关键词: Selenium  Japanese seabass  Nutrient requirement  Middle growth stage

中文摘要:

      以初始体重为(214.5±1.0) g的鲈鱼为研究对象，通过在基础饲料中添加亚硒酸钠0、0.48、0.97、1.45、1.93、2.42 mg/kg配成不同水平硒(0.12、0.36、0.42 、0.60、0.78、1.10 mg/kg)的6组等氮等脂饲料，在海水浮式网箱进行为期70 d的生长实验，探讨饲料中不同水平的硒对鲈鱼生长、饲料利用、抗氧化酶活力和鱼体硒含量的影响。研究表明，特定生长率随着饲料中硒水平的增加呈先上升后平稳的趋势，在饲料中硒水平为0.60 mg/kg时，特定生长率最高；饲料中不同水平的硒对鲈鱼存活率和饲料效率无显著差异(P>0.05)；肝脏和血清中的谷胱甘肽过氧化物酶(GSH-Px)活性随着饲料硒水平的提高而呈现出先升高后降低的趋势，在饲料硒含量为0.60 mg/kg时达到最大值；血清和肝脏谷胱甘肽转移酶(GST)活性随着硒含量的增加呈现出先上升后平缓的趋势，在饲料中硒含量为0.78 mg/kg时，血清GST活性显著高于对照组(P<0.05)；血清谷胱甘肽还原酶(GR)活性随着硒含量的增加呈现先上升后平缓的趋势，在饲料中硒含量为0.78 mg/kg时，血清GR活性显著高于对照组(P<0.05)；血清中超氧化物歧化酶(SOD)活性随着饲料硒含量的升高呈现出先升高后下降的趋势，在饲料中硒含量为0.60 mg/kg时达到最大值，硒含量为1.10 mg/kg时，血清中SOD活性显著下降且低于对照组饲料(P<0.05)；随着饲料硒含量的升高，血清中丙二醛含量呈现出先降低而后升高的趋势，其中在饲料中硒含量为0.60 mg/kg时最低；全鱼和肝脏中硒含量随着饲料中硒水平的升高而显著升高(P<0.05)。综合生长和抗氧化能力，建议214 g规格的鲈鱼饲料中适宜的硒含量为0.63 0.75 mg/kg。

英文摘要:

      In this study we conducted a 10-week feeding trial to evaluate the effects of dietary selenium on the growth, the physiological status and the body composition of Japanese seabass with initial average weight of (214.5±1.0) g. Six semi-purified diets were supplemented with NaSeO3•H2O and the concentrations of Se were 0.12, 0.36, 0.42, 0.60, 0.78 and 1.10 mg/kg．In seawater floating net cages (1.5 m×1.5 m×2 m), a group of 18 fish was fed with these six diets twice daily and every 3 fish had one type of diet. The survival rate and the feed efficiency were not significantly affected by the increased level of dietary Se (P>0.05). The weight gain and the whole body crude protein were the highest in Japanese seabass fed with 0.60 mg Se/kg (diet) (P<0.05). Hepatopancreas and the level of the whole body selenium were positively correlated to the dietary Se level. The activities of both serum and heaptopancreas glutathione peroxidases (GSH-Px) were increased along with the elevated dietary Se level, and peaked at 0.60 mg Se/kg (diet) (P<0.05). When the dietary Se increased to 0.78 mg/kg, the activity of the serum GSH-Px decreased significantly (P<0.05). The activities of both serum and hepatopancreas glutathione S-tramsferase (GST) initially decreased and then increased along with the elevated dietary Se level. The activity of serum GST was significantly higher in the 0.78 mg/kg group than in the 0.12 mg/kg group (P<0.05). The activity of serum glutathione reductase (GR) was also significantly affected by the dietary selenium level, and was significantly higher in the 0.78 mg/kg group than in the 0.12 mg/kg group (P<0.05). The activity of serum superoxide dismutase (SOD) increased along with the elevated dietary Se level up to 0.60 mg/kg, and then declined (P<0.05). The activity of serum SOD was significantly decreased in the 0.78 mg/kg group compared to the 0.12 mg/kg group (P<0.05). The level of malonaldehyde (MDA) was initially decreased and then increased along with the elevated dietary Se level. Japanese seabass in the 0.60 mg/kg group showed the lowest level of MDA, which was distinct from the control group and the 1.0 mg/kg group (P<0.05). These results indicated that 0.60 mg Se/kg (diet) might promote the growth and the anti-oxidative ability of Japanese seabass. Quadrate broken-line analysis with specific qrowth rate (SGR) showed that 0.63 mg Se/kg (diet) could be optimal for the growth of Japanese seabass.