小肽制品对凡纳滨对虾蛋白酶和淀粉酶活力的影响

采用单因子浓度梯度法,基础饲料中加入0.1%、0.5%、1.0%、1.5%、2.0%、2.5%六个不同添加梯度的小肽制品,以基础饲料为对照,饲喂凡纳滨对虾(Litopenaeusvannamei),初始体重0.084g。37d后,测定凡纳滨对虾的蛋白酶和淀粉酶活力。结果表明,添加不同水平的小肽制品对凡纳滨对虾的肝胰腺类胰蛋白酶活力没有显著影响(P>0.05),但添加1.0%和1.5%小肽可极显著地提高凡纳对虾的胃和肝胰腺的胃蛋白酶活力及胃和肠的类胰蛋白酶活力(P>0.01),同时添加1.0%小肽可极显著提高凡纳滨对虾胃和肠的淀粉酶活力(P>0.01),添加1.5%小肽显著提高凡纳滨对虾肝胰腺淀粉酶活力(P>0.05)。     

Genetic monitoring of broodstocks of the marine shrimp Litopenaeus vannamei in a closed rearing system in Pernambuco,Brazil

Loss of genetic variability can be detrimental to a population's survival traits and fitness. These effects are likely to be maximized in shrimp closed broodstock rearing systems where post‐larvae are often produced from crosses of breeders collected from an associated grow‐out farm after mass selection. Longtime broodstock management in closed systems is also expected to lead to reduction in or even complete eradication of genetic variability. The present work aimed at monitoring the genetic variability of a Litopenaeus vannamei hatchery in the state of Pernambuco (Brazil), during three successive replacements, using microsatellite markers. No significant genetic diversity losses have been observed through the values of mean heterozygosity (H_o=0.460 and H_e=0.660 in the first sample; H_o=0.420 and H_e=0.620 in the second sample; and H_o=0.600 and H_e=0.660 in the third sample). However, some alleles appear to have been lost after three replacements. The diversity level was considered to be high and is comparable to those reported for wild populations, suggesting that the original imported founder stock of Brazilian L. vannamei is likely to have had a high genetic diversity, possibly due to multiple origins.     

对虾IHHNV荧光定量PCR检测方法的建立

根据G enBank中对虾传染性皮下和造血器官坏死病毒( IHHNV) 保守基因序列( AF218226), 设计合成了1对引物和1条TaqM an探针, 建立了检测IHHNV的荧光定量PCR技术。将建立的荧光定量PCR检测方法与常规PCR对比。结果显示, 所建立的荧光定量PCR 方法灵敏度可达2个拷贝, 比常规PCR 灵敏度高1 000倍。对保存的15份经常规PCR检测为IHHNV 阳性的DNA 样品进行荧光定量PCR检测, 结果都为阳性, 检测的病毒含量为2. 15 @ 107 ~ 4. 21 @ 104 拷贝/LL。用该方法对不同浓度的样品进行了重复检测, 表明该方法具有良好的重复性, 可满足IHHNV的临床诊断需要。     

Glycosaminoglycans from Litopenaeus vannamei Inhibit the Alzheimer’s Disease β Secretase,BACE1

Only palliative therapeutic options exist for the treatment of Alzheimer’s Disease; no new successful drug candidates have been developed in over 15 years. The widely used clinical anticoagulant heparin has been reported to exert beneficial effects through multiple pathophysiological pathways involved in the aetiology of Alzheimer’s Disease, for example, amyloid peptide production and clearance, tau phosphorylation, inflammation and oxidative stress. Despite the therapeutic potential of heparin as a multi-target drug for Alzheimer’s disease, the repurposing of pharmaceutical heparin is proscribed owing to the potent anticoagulant activity of this drug. Here, a heterogenous non-anticoagulant glycosaminoglycan extract, obtained from the shrimp Litopenaeus vannamei, was found to inhibit the key neuronal β-secretase, BACE1, displaying a more favorable therapeutic ratio compared to pharmaceutical heparin when anticoagulant activity is considered.     

高密度CO2诱导制备虾糜凝胶的特性

为了探索高密度CO2诱导制备蛋白凝胶的可行性,以南美白对虾虾糜为材料,以常压热诱导凝胶为对照,研究压力5～30MPa、时间10～50min、温度50～70℃等因素对虾糜凝胶特性以及基本营养成分的影响。结果表明,高密度CO2处理能够使虾糜形成凝胶,压力、时间和温度对虾糜凝胶特性均有显著影响,在20MPa、60℃、30min和25MPa、60℃、30min条件下制备的虾糜凝胶品质相对较好;与热诱导凝胶相比,高密度CO2诱导的虾糜凝胶强度更大,同时也显著增加了虾糜凝胶的持水能力,减少了营养物质的流失。研究结果表明,高密度CO2具有促进凝胶形成和改善凝胶特性的作用,可以成为替代热处理成为蛋白凝胶制品生产的新技术。     

密度和碳水化合物水平对凡纳滨对虾存活和生长的影响

研究了密度(361．20、722．40和1083．60尾/m2)和碳水化合物水平(15．47％、29．15％和41．00％) 对凡纳滨对虾存活和生长的影响。5周的饲养结果表明:在三个密度水平,随碳水化合物水平的升 高,对虾存活率和特定生长率均呈下降趋势,而饲料系数呈上升趋势;在三个碳水化合物水平,随密 度的升高,对虾存活率、特定生长率、摄食量和饲料系数均呈下降趋势。     

不同水平低聚木糖对凡纳滨对虾生长、免疫及抗氨氮胁迫能力的影响

为探讨不同水平低聚木糖对凡纳滨对虾幼虾生长性能、主要免疫酶活力及抗氨氮胁迫能力的影响,本试验选取初始体质量(0.33±0.00)g的凡纳滨对虾幼虾480尾,随机分为四组,分别投喂含0、250、500、1000 mg/kg低聚木糖的四种饲料。养殖42 d,随后进行24 h氨氮胁迫试验,测定其生长指标,血清的超氧化物歧化酶(SOD)、过氧化氢酶(CAT)、酸性磷酸酶(ACP)、碱性磷酸酶(AKP)、多酚氧化酶(PPO)活力、溶菌酶(LZM)、总抗氧化能力(TAOC)和丙二醛(MDA)含量。结果显示:随着饲料中低聚木糖水平的增加,凡纳滨对虾的增重率(WGR)和特定生长率(SGR)先升高后降低(P> 0.05)。养殖试验结束后,250 mg/kg组和1000 mg/kg组中SOD含量显著高于对照组和500 mg/kg组(P <0.05),且分别高于对照组109.09%和86.49%;LZM、T-AOC、CAT和PPO活力均在500 mg/kg组达到最高,且T-AOC能力和PPO活力显著高于其他组(P <0.05),分别高于对照组74.30%和147.47%,对照组CAT活力显著低于其他各组(P <0.05);MDA含量先上升后下降,各组间差异并不显著(P> 0.05)。氨氮胁迫试验后,SOD、LZM、CAT、AKP和T-AOC的活力先上升后下降,且250 mg/kg组SOD活力显著高于对照组(P <0.05),增长了67.92%,250 mg/kg组和500 mg/kg组中CAT活力显著高于对照组(P <0.05),分别升高了37.08%和36.67%;500 mg/kg组和1000 mg/kg组中PPO活力显著高于对照组(P <0.05),分别增长了80.28%和86.39%;MDA含量呈上升趋势,但各组间差异并不显著(P> 0.05)。由此可见,饲料中添加250 mg/kg的低聚木糖对凡纳滨对虾的生长有积极的促进作用,且低聚木糖添加水平为250～500 mg/kg时可提高凡纳滨对虾免疫能力及抗氨氮胁迫能力。     

饲料中铬源及铬添加水平对凡纳滨对虾幼虾生长性能、血清生化指标及非特异性免疫酶活性的影响

本试验旨在研究饲料中铬源及铬添加水平对凡纳滨对虾幼虾生长性能、血清生化指标及非特异性免疫酶活性的影响,探讨3种铬源在饲料中的最适添加水平。采用双因素试验设计,铬源分别为氯化铬(Cr Cl3)、吡啶甲酸铬(Cr-Pic)和蛋氨酸铬(Cr-Met),铬添加水平分别为0、0.3、0.6、0.9、1.2和2.0 mg/kg,配制成16种试验饲料,投喂凡纳滨对虾幼虾8周。挑选初始体重为(0.897±0.001)g的凡纳滨对虾幼虾1 920尾,随机分为16组,每组3个重复,每个重复40尾。结果表明:铬源、铬添加水平及两者的交互作用对凡纳滨对虾的终末体重、增重率、饲料系数和蛋白质效率有显著影响(P0.05)。铬添加水平为0.3~2.0 mg/kg的各组幼虾的终末体重、增重率显著高于未添加铬组(P0.05),以Cr-Met形式添加0.9 mg/kg铬时上述指标达到最大值。Cr Cl3和Cr-Met组在铬添加水平为0.9 mg/kg时饲料系数最低,但与铬添加水平为1.2 mg/kg时差异不显著(P0.05);Cr-Pic组在铬添加水平为1.2 mg/kg时饲料系数最低。3种铬源下,蛋白质效率均在铬添加水平为0.9 mg/kg时达最大值,但与铬添加水平为1.2mg/kg时差异不显著(P0.05)。铬源、铬添加水平及两者的交互作用对全虾粗脂肪和粗灰分含量有显著影响(P0.05),但对全虾粗蛋白质和水分含量无显著影响(P0.05)。铬源、铬添加水平及两者的交互作用对血清总蛋白、葡萄糖、胆固醇和甘油三酯含量均有显著影响(P0.05),以Cr-M et形式添加0.9 mg/kg铬时呈现出最高的血清总蛋白含量和最低的血清葡萄糖含量。铬源、铬添加水平及两者的交互作用对血清碱性磷酸酶、酸性磷酸酶、酚氧化物酶及总超氧化物歧化酶活性有显著影响(P0.05),以Cr-Met形式添加0.9 mg/kg铬时血清酚氧化物酶和总超氧化物歧化酶活性最高。以增重率为评价指标,以Cr Cl3、Cr-Pic和Cr-Met为铬源时,经折线模型得出饲料中铬的适宜添加水平分别为1.33、1.27、1.04 mg/kg。通过比较可知,Cr-Met的相对生物利用率最高,Cr-Pic次之,Cr Cl3最低。     

Water quality,production parameters and nutritional condition of Litopenaeus vannamei (Boone, 1931) grown intensively in zero water exchange mesocosms with artificial substrates

The effect of artificial substrates on the water quality, production parameters and nutritional condition was assessed in experimental intensive cultures of Litopenaeus vannamei grown in mesocosm units with zero water exchange. The initial stocking densities in triplicate 1000 L tanks were 600 and 800 g of juvenile shrimp (2.7 g) per unit, with (W) and without (WO) artificial substrates. There were no significant differences between the water quality parameters of the four treatments. In the tanks with the lower stocking biomass, the best survival (96.7% vs. 87.0%), growth rate (1.69 vs. 1.35 g week⁻¹), final biomass (1969.6 vs. 1516.0 g m³) and feed conversion ratio (1.30 vs. 1.90) were obtained with artificial substrates. Similar results were observed for the higher stocking biomass (90.9% vs. 74.5%, 1.50 vs. 1.13 g week⁻¹, 2221.6 vs. 1560.8 g m³, and 1.50 vs. 2.60 respectively). The nutritional condition of shrimp was improved using artificial substrates. The protein content in muscle was higher (21.6% and 20.4%) in ponds with substrates as compared with the control (21.2% and 15.9%).