角毛藻营养及其不同添加量对凡纳滨对虾育苗水质以及仔虾生长、非特异性免疫和抗逆性能的影响

Nutrition of Chaetoceros muelleri and Effects on Breeding Water Quality,Growth,Non-Specific Immunity and Resistant Capability of Shrimp Larvae of Litopenaeus vannamei in Different Addition Amount

本试验旨在研究角毛藻营养及其不同添加量对凡纳滨对虾育苗水质以及仔虾生长、非特异性免疫和抗逆性能的影响。本试验首先检测了牟氏角毛藻的营养成分,然后从对虾溞状幼体开始,每组分别添加0(对照组)、0.5×10^(5)(试验组Ⅰ)、1.0×10^(5)(试验组Ⅱ)、2.0×10^(5)(试验组Ⅲ)和4.0×10^(5)个细胞/mL(试验组Ⅳ)的牟氏角毛藻进行育苗试验,直至糠虾Ⅱ期,每组将15万尾凡纳滨对虾健康无节幼体放置在1000 L的黑桶中培育,每组3个重复。结果表明:1)牟氏角毛藻水分、粗蛋白质、粗脂肪和粗灰分含量分别为75.23%、14.30%、2.97%和7.50%;必需氨基酸含量占氨基酸总量的46.82%,鲜味氨基酸含量占氨基酸总量的40.42%;牟氏角毛藻含18种脂肪酸,其中饱和脂肪酸(SFA)8种,占脂肪酸总量的39.40%,不饱和脂肪酸(UFA)10种,占脂肪酸总量的50.29%。2)牟氏角毛藻可改善育苗池水质,促进虾苗生长、提高出苗率,其中试验组Ⅲ、试验组Ⅳ优势明显,与其他各组差异显著(P<0.05),但二者差异不显著(P>0.05)。试验组饵料消耗量随着牟氏角毛藻添加量的增加而下降,除试验组Ⅰ外,其余试验组饵料消耗量与对照组差异显著(P<0.05)。3)试验组仔虾淀粉酶、脂肪酶和蛋白酶活性随着牟氏角毛藻添加量的提高而增加,试验组Ⅳ仔虾淀粉酶活性与对照组差异显著(P<0.05),其余各组间差异不显著(P>0.05);试验组仔虾脂肪酶和蛋白酶活性与对照组差异显著(P<0.05),试验组Ⅱ、试验组Ⅲ和试验组Ⅳ间无显著差异(P>0.05)。4)试验组仔虾总抗氧化能力(T-AOC)、超氧化物歧化酶(SOD)和过氧化物酶(POD)的活性随着牟氏角毛藻添加量的提高而增加,与对照组差异显著(P<0.05);试验组仔虾酸性磷酸酶(ACP)和碱性磷酸酶(AKP)的活性与对照组间无显著差异(P>0.05)。5)各组间的仔虾在3.0×10^(-4)mL/L甲醛质量密度的应激下,随应激时间的增加存活率逐步下降,24 h后试验组仔虾的存活率分别比对照组提高11.45%、22.90%、24.41%和37.40%,组间差异显著(P<0.05)。综上所述,牟氏角毛藻个体较小,运动弱,营养丰富,是适合作为对虾幼体的开口料和育苗期间的良好饵料。牟氏角毛藻可以降低水中氨氮、亚硝酸盐氮等有害因子的含量和化学需氧量,消除应激因素,保持水质稳定,有利于对虾的生长。牟氏角毛藻添加量在1.0×10^(5)~2.0×10^(5)个细胞/mL可提高消化酶活性和免疫性能,提高虾仔的出苗率。

The experiment was aimed to study the nutrition of Chaetoceros muelleri and effects of Chaetoceros muelleri on the breeding water quality,growth,non-specific immunity and resistant capability of Litopenaeus vannamei in different addition amount.In this experiment,the nutrition composition of Chaetochetes mouti was detected firstly,and then 0(control group),0.5×10^(5)(test groupⅠ),1.0×10^(5)(test groupⅡ),2.0×10^(5)(test groupⅢ)and 4.0×10^(5) cell/mL(test groupⅣ)of Chaetoceros mouterii were added in each group to carry out seedling test from zoea to mysisⅡperiod.A total of 1.5×10^(5) healthy nauplii of Litopenaeus vannamei in each group was placed in 1000 L black barrel,with 3 replicates per group.The results showed as follows:1)the contents of water,corde protein,crude fat and ash were 75.23%,14.30%,2.97%and 7.50%in Chaetoceros muelleri,respectively.The contents of essential amino acids accounted for 46.82%of total amino acids,and those of umami amino acids accounted for 40.42%of total amino acids.There were 18 kinds of fatty acids in Chaetoceros muelleri,among which 8 kinds of saturated fatty acids accounted for 39.40%of total fatty acid content and 10 kinds of unsaturated fatty acids accounted for 50.29%of total fatty acid content.2)Chaetoceros muelleri could improve breeding water quality,promote growth,improve the germination rate of young shrimps,test groupsⅣandⅢhad obvious advantages,and had significant differences from other groups(P<0.05),but feed difference between those two group was not significant(P>0.05).The diet consumption of test groups decreased with the increase of the supplemental level of Chaetoceros muelleri.Except for test groupⅠ,the feed consumption of other test groups was significantly different from that of control group(P<0.05).3)The activities of amylase,lipase and proteinase in the test groups were increased with the increase of the addition of Chaetoceros muellerii,respectively.The amylase activity of larvae in test groupⅣwas significantly different from that in control group(P<0.05),but there was no significant difference among other groups(P>0.05).Lipase and protease activities of shrimp in test groups were significantly different from those in control group(P<0.05),but there were no significant differences among test groupsⅡ,ⅢandⅣ(P>0.05).4)The total antioxidant capacity(T-AOC)and the activities of superoxide dismutase(SOD)and peroxidase(POD)in the test groups were increased with the increase of the addition of Chaetoceros muellerii,respectively,which were significantly different from the control group(P<0.05),respectively.The activities of acid phosphatase(ACP)and alkaline phosphatase(AKP)in the test groups were no significantly different from the control group(P>0.05).5)Under the stress of formaldehyde at 3.0×10^(-4) mL/L,the survival rate of post-larval in each group gradually decreased with the increase of stress time.After 24 h,the survival rate of larvae in test groups was 11.45%,22.90%,24.41%and 37.40%higher than that in control group,respectively,and the difference among groups was significant(P<0.05).Chaetoceros muelleri is suitable initial feeding for shrimp larvae and good feed during seedling raising because of its small size,weak exercise ability and abundant nutrition.Chaetoceros muelleri can reduce the contents of harmful factors such as ammonia nitrogen,nitrite nitrogen and chemical oxygen demand in water,eliminate stress factors and maintain stable water quality and conducive to the growth of shrimp.In summary,Chaetoceros muelleri can improve the activity of digestive enzymes,immune factors and the emergence rate of shrimp post-larvae at 1.0×10^(5) to 2.0×10^(5) cell/mL addition amount of Chaetoceros muelleri.