凡纳滨对虾3 个引进群体及其杂交子代的生长性能评估

以3个凡纳滨对虾(Litopenaeus vannamei)引进群体为亲本,按照Griffing I方法进行双列杂交,对子代杂交组合体质量进行长期跟踪测量,分析幼虾阶段、成虾阶段、留种阶段的特定生长率和杂种优势率。研究结果表明,9个交配组合群体3个生长发育阶段体质量最小二乘均值的变化范围分别为5.86~12.15 g、14.79~28.82 g和38.25~54.74 g,其中各生长发育阶段杂交组均值均比自交组高。各阶段的特定生长率分别为3.40~5.70%/d、1.11~2.56%/d和0.33~0.68%/d。杂种优势分析结果显示,凡纳滨对虾各杂交组合体质量存在较明显的杂种优势,幼虾阶段、成虾阶段、留种阶段表现为递减趋势,其中迈阿密SIS的M群体母本与夏威夷的H群体父本杂交组合(M-H)杂种优势率最高。M群体作为父本亦或母本其子代体质量的最小二乘均值均较高,且不同生长阶段双亲均值均高于3个群体的均值,属于相对优良的亲本,M-H和M-T杂交组合属于优选杂交组合。该研究为进一步家系选育基础群体的建立提供了技术参数和理论依据。     

Bacterial communities and predicted nitrogen metabolism of heterotrophic‐ and probiotic‐based biofilms used for super‐intensive indoor shrimp culture

Biofilm‐based aquaculture systems constitute a promising alternative for intensive shrimp rearing. Microorganisms forming biofilms can recycle the nitrogen compounds the production units improving the water quality while using zero or limited water exchange. This study aimed to compare the taxonomic profiles and the predicted functions related to the transformation of nitrogenous compounds between a heterotrophic‐ (HtB) and a probiotic biofilm (PrB), and the effect of these on the water quality and the productive response of cultured shrimp. Libraries of the 16S‐rRNA gene (V3‐V4 region) were prepared and sequenced to be used as a taxonomic biomarker. Analysis of metagenomic datasets revelated that genera Halomonas, Planctomycetes and Rhodopirellula were the most abundant genera in HtB; meanwhile, Bacillus, Halobacillus and Flavobacterium dominated in PrB. Regarding nitrogen metabolism, the proportion of genes encoding enzymes catalyzing the six pathways shaping the nitrogen metabolism showed differences between biofilms, which could also explain the difference in water quality between treatments. Concerning the productive response of shrimp, no significant differences were detected except for survival, which was higher in PrB. Finally, the results suggest that biofilms harbour functions for nitrogen metabolism, including dissimilatory nitrate reduction, assimilatory nitrate reduction, denitrification, nitrification, nitrogen fixation and anammox; however, the balance of these functional capabilities seems to be relevant to maintain water quality.     

中草药免疫增强剂对南美对虾血液生化指标的影响

该研究针对南美白对虾的生理特点,采用中医的辨证施治方法,选用具有补脾益气、消食导滞、催肥增重和增强免疫力等许多优点的中草药组方作为南美白对虾的中草药免疫增强剂。试验结果表明,饲料日粮中添加中草药免疫增强剂的南美白对虾比对照组增重明显,为了验证中草药免疫增强剂的作用原理,试验进行了南美白对虾实验组和对照组几种常见血液免疫生化指标的检测,发现用过中草药免疫增强剂的南美白对虾血液免疫生化指标几种常见体酶的活力有不同程度的提高,由此证实了中草药免疫增强剂对南美白对虾的免疫效果。     

东方对虾饲料不同蛋白源的比较

本试验以鱼粉(F),豆饼(S)和棉籽饼(C)作为东方对虾饲料的主要蛋白源。为适应实际生产的需要,还设计了以混合蛋白源(M)组成的饲料。每种蛋白源的饲料设计了两个粗蛋白水平:前期46%和后期44%。用8种饲料(M-46,F-46,S-46,C-46,M-44,F-44,S-44和C-44)饲喂初重为6.1 g 的东方对虾,观察不同蛋白源对试验对虾的成活率、生长性能和饲料转化率的影响。本试验还以 Cr_2O_3为指示剂,测定东方对虾对不同蛋白源的粗蛋白和主要氨基酸的消化率。为期42 d 的试验结果表明,不同蛋白源对所观察指标有显著影响。     

南美白对虾中喹乙醇及其代谢物3-甲基-喹恶啉-2-羧酸残留的高效液相色谱-串联质谱检测

以南美白对虾为试验材料,建立了喹乙醇(OLA)及3-甲基-喹恶啉-2-羧酸(MQCA)多残留的高效液相色谱-串联质谱(HPLC-MS/MS)确证检测法。组织样品经2 mol/L盐酸提取,Oasis HLB固相萃取柱净化,采用HPLC-MS/MS仪进行测定。质谱检测采用正离子选择反应监测模式,外标法定量。样品中OLA和MQCA质量分数分别为2~200和4~200μg/kg时,线性关系良好;当质量分数分别为2~50和4~50μg/kg时,平均回收率为93.9%~103.2%,变异系数为6.3%~11.5%。OLA及MQCA的检测限分别为0.5和1.0μg/kg,定量限分别为2.0和4.0g/kg。该方法灵敏、准确、简便、快速,适于南美白对虾中OLA及MQCA残留的同时定量分析和确证检测。