蚯蚓粉替代鱼粉对大鳞副泥鳅生长、肌肉成分、血清生化指标及免疫性能的影响

以初始体重为(3.86±0.23)g的大鳞副泥鳅(Paramisgurnus dabryanus)为试验对象,研究蚯蚓(Eisenia foetida)粉替代鱼粉对其生长、肌肉成分、血清生化指标及免疫性能的影响。以0代替鱼粉为对照组,用蚯蚓粉替代25%、50%、75%、100%的鱼粉配制成5组等氮等能饲料,在网箱中进行10周的养殖试验。结果显示,饲料中的蚯蚓粉替代鱼粉对大鳞副泥鳅的存活率无显著影响;随着替代水平的升高,饲料系数、增重率升高(P0.05),肥满度、肝体比降低(P0.05)。各组间脾体比、特定生长率均无显著性差异;75%和100%替代组肌肉粗脂肪含量显著高于对照组(P0.05),100%替代组粗蛋白和水分含量显著低于对照组(P0.05)。随着饲料中蚯蚓粉水平的上升,鱼体肌肉蛋白质的精氨酸、胱氨酸、天门冬氨酸含量升高(P0.05),脯氨酸、组氨酸、蛋氨酸、苏氨酸、苯丙氨酸含量显著降低(P0.05);各组间血清谷丙转氨酶活力、高密度脂蛋白胆固醇含量、脂肪酶和淀粉酶活性均无显著性差异(P0.05)。随着代替水平的上升,血清甘油三酯和总胆固醇含量显著升高(P0.05),谷草转氨酶显著降低(P0.05);随着替代水平的继续上升,肝胰脏过氧化氢酶、谷胱甘肽过氧化物酶、溶菌酶活力下降,肝胰脏丙二醛含量、碱性磷酸酶活力、攻毒后的发病率和死亡率上升。各组间的肝胰脏总超氧化物歧化酶活力和总抗氧化能力均无显著性差异(P0.05)。研究表明,本实验条件下,蚯蚓粉可部分替代(22%)饲料鱼粉而不影响大鳞副泥鳅的生长和存活,且能提高鱼体肌肉成分,有效预防肝胰脏损伤和过氧化,但显著降低了鱼类免疫性能(P0.05)。

Effects of substituting fishmeal with earthworm (Eisenia foetida) meal on growth, muscle composition, serum biochemistry index and immunity performance in the loach Paramisgurnus dabryanus

This study evaluates the effects of substituting fishmeal with earthworm meal on the growth, muscle composition, and biochemistry index in serum and immunity performance in the loachParamisgurnus dabryanus with an average initial body weight of (3.86±0.23) g. Five experimental diets with the same nitrogen and energy content were formulated to replace fishmeal using 0 (as the control group), 25%, 50%, 75% and 100% of earth-worm meal. The experimental fish were fed the alternative diets in net cages for 10 weeks. Results showed that dietary fishmeal replacement with earthworm meal had no significant effect on the survival rate of loach. The feed conversion ration (FCR) and weight gain rate (WGR) increased (P<0.05), and the condition factor (CF) and hepa-tosomatic index (HSI) decreased (P<0.05), as levels of substitution rose to the maximum. There was no significant difference in splenic index (SI) or specific growth rate (SGR) in any of the groups. The content of fat in the flesh at levels of 75% and 100% replacement was significantly higher compared with the control group (P<0.05); and the content of flesh crude protein and moisture in the 100% replacement diet was significantly lower than in the control group (P<0.05). As the content of earthworm meal rose, the content of Arg, Cys and Asp in flesh protein also increased (P>0.05), but that of Pro, His, Met, Thr and Phe in flesh protein decreased significantly (P<0.05). There was no significant difference (P>0.05) in the vitality of alanine aminotransferase (ALT), lipase (LPS) and amylase (AMS), or in the content of high density lipoprotein cholesterol (HDL-C)in the serum of treatment groups. As the fishmeal content dropped, triglyceride (TG) and total cholesterol (TCHO) increased (P<0.05), but aspartate ami-notransferase (AST) decreased significantly (P<0.05). As levels of substitution increased up to the maximum, the vitality of catalase, glutathion peroxidase (GSH-Px) and lysozyme (LZM) in the hepatopancreas decreased; the content of malonaldehyde (MDA) and the vitality of alkaline phosphatase (AKP) in the hepatopancreas increased; and morbidity and death rate after bacteriumAeromonas hydrophila challenge also increased. There was no sig-nificant difference in the vitality of total superoxide dismutase (TSOD) and total antioxidant capacity in the hepa-topancreas of treatment groups (P>0.05). This study demonstrated that replacing 22% of the fishmeal in the diet by earthworm meal had no significant effect on growth and survival, and could promote muscle composition. It could also effectively protect the hepatopancreas from damage and peroxidation by reactive oxygen; however, it would significantly inhibit loach immunity performance.