Effects of fishmeal replacement by Tenebrio molitor meal on growth performance,antioxidant enzyme activities and disease resistance of the juvenile pearl gentian grouper (Epinephelus lanceolatus ♂ × Epinephelus fuscoguttatus ♀)

A 50‐day feeding trial was conducted for juvenile pearl gentian grouper (Epinephelus lanceolatus ♂ × Epinephelus fuscoguttatus ♀) to determine the optimal amount of Tenebrio molitor meal (TM) that could replace fishmeal (FM) in feeds without reducing growth performance, antioxidant enzyme activities and resistance. Six isonitrogenous and isolipidic diets were formulated with TM replacing 0% (T0), 6.25% (T6), 12.5% (T12), 18.75% (T18), 25% (T25), 31.25% (T31) FM respectively. Each diet was randomly divided into triplicate groups with 30 juveniles (initial weight 6.60 ± 0.00 g). After feeding trail, fish were challenged by Vibrio harveyi for 7 days. The results showed that each treatment had better survival rate between 96.67% and 100%. Fish fed with control and T6 diet showed lower final weight and weight gain rate as compared to other diets. The feed conversion ratio of fish fed on T12 and T18 diet had no significant difference compared to control diet. As compared to control diet, other diets had no significant differences on specific growth rate and temperature growth coefficient. Fish fed with T6 diet had highest liver glutathione reductase activities. No significant differences were observed in liver superoxide dismutase activities in fish fed with T6, T12, T25, T31 and control diet. Fish fed on T18 diet had lowest hepatic malondialdehyde contents and a highest relative per cent survival. According to a broken‐line model, the recommended substituted ratio of TM for FM was estimated to be 12.3% for grouper obtaining maximum WGR, corresponding to additive amount of TM is 4.92%.     

Comparative chemical,taste, and functional components in different tissues of giant grouper (Epinephelus lanceolatus)

The chemical composition, nutrition, and flavor components of various giant grouper tissues were determined. The muscle protein content was about 20%, and the muscle fat content was in the range of 3.9–6.4%, which is higher than that of most other groupers. The bone had the highest fat value (12.5–14.2%). The major nucleotide-related compound in the tissues was inosine monophosphate (IMP); whereas in the skin, adenosine monophosphate (AMP) was predominant. The predominant free amino acid (FAA) in the tissues was taurine (Tau), followed by arginine (Arg), lysine (Lys), and glycine (Gly). Tau content was higher in chin meat, and lower in bone. The total peptide content was in the range of 660–1,390 mg/100 g, which was much higher than that observed in other fish species. Muscle was rich in C16:0, C18:0, C18:1, and omega-3 highly unsaturated fatty acids, eicosapentaenoic acid (EPA), and docosahexaenoic acid (DHA).     

Modeling the Decision-Making Behavior of Fishers in the Reef Fish Fishery on the West Coast of Florida

When, where, and how a commercial vessel fishes determines the temporal and spatial placement of the data they are legally bound to supply to management agencies. Data provided by commercial fishing vessels are used in assessments to infer fish population abundance. Fisher decision-making may also allow fishers to dissipate the benefits of regulations and affect expected management outcomes. Decisions about participation, site choice, and trip termination were modeled for commercial fishers in the Gulf of Mexico. Vessel logbook data were used to parameterize discrete choice models for each decision. A questionnaire of vessel captains (N = 40) helped inform model structure. Results suggested that participation and site choice decisions may be nested, and are affected by expected revenue, regulations, fish price, wind speed, vessel characteristics, and fuel price. Trip termination was influenced by regulations, wind speed, and catch relative to fish hold capacity. Assessment and management implications are discussed.     

赤点石斑鱼血清与皮肤黏液的SDS-PAGE蛋白电泳分析

以正常生活状态下的非免疫赤点石斑鱼(Epinephelus akaara)为材料,采用SDS-PAGE蛋白电泳技术,分析和比较了全血清和皮肤黏液中的蛋白区带数。结果表明:赤点石斑鱼血清与皮肤黏液蛋白图谱不完全相同,其中相同的蛋白区带数为9条,血清中特有蛋白带为16条,皮肤黏液中特有蛋白带为10条。计算机辅助分析蛋白图谱,结果提示:赤点石斑鱼血清及皮肤黏液中免疫球蛋白(Ig)的轻链大小为25.0 ku,重链为73.2 ku。该试验为进一步研究赤点石斑鱼皮肤黏液Ig的理化性质奠定基础。     

幼鱼和养成阶段斜带石斑鱼对饲料中脂肪的需要量

本试验旨在探讨2个生长阶段(幼鱼和养成阶段)斜带石斑鱼对饲料中脂肪的需要量。以鱼油调整饲料脂肪水平,配制5种脂肪水平(7.07%、9.92%、12.92%、15.95%和19.04%)的等氮饲料,分别投喂体重为9.1 g(幼鱼阶段)的斜带石斑鱼8周和体重为102.6 g(养成阶段)的斜带石斑鱼10周。同一生长阶段,每种饲料设3个重复,每个重复幼鱼阶段放养25尾鱼,养成阶段放养20尾鱼。结果表明:1)随着饲料脂肪水平的升高,幼鱼和养成阶段石斑鱼的增重率(WGR)、特定生长率(SGR)、蛋白质效率(PER)、肥满度(CF)和脏体比(VSI)均随着饲料脂肪水平的升高呈先上升后下降趋势,饲料系数(FCR)则呈相反的变化趋势,上述指标均在饲料脂肪水平为12.92%时获得极值。2)随着饲料脂肪水平的升高,幼鱼和养成阶段石斑鱼的全鱼粗蛋白质含量逐渐下降,全鱼和肌肉粗脂肪含量逐渐上升,全鱼和肌肉水分含量无显著变化(P0.05),全鱼和肌肉其他常规营养成分含量无规律性变化。3)随着饲料脂肪水平的升高,幼鱼和养成阶段石斑鱼的血浆总蛋白(TP)和低密度脂蛋白(LDLC)含量呈逐渐下降趋势,血浆高密度脂蛋白(HDLC)含量呈逐渐升高趋势。幼鱼和养成阶段石斑鱼的血浆甘油三酯(TG)和总胆固醇(CHOL)含量与饲料脂肪水平呈线性或曲线关系。4)随着饲料脂肪水平的升高,幼鱼和养成阶段石斑鱼的肝脏肝脂酶(HL)、脂蛋白脂酶(LPL)、苹果酸脱氢酶(MDH)活性均逐渐下降,而肝脏乳酸脱氢酶(LDH)活性则逐渐上升。5)随着饲料脂肪水平的升高,幼鱼阶段肝脏酸性磷酸酶(ACP)活性无显著变化(P0.05),养成阶段肝脏ACP活性逐渐下降,幼鱼和养成阶段肝脏超氧化物歧化酶(SOD)活性先升高后降低。幼鱼和养成阶段石斑鱼肝脏碱性磷酸酶(AKP)和溶菌酶(LZM)活性与饲料脂肪水平呈正相关关系。6)随饲料脂肪水平的升高,幼鱼和养成阶段石斑鱼的胃肠道胃蛋白酶和淀粉酶活性逐渐下降,胃肠道脂肪酶活性逐渐上升。综上,在本试验条件下,饲料中适宜水平的脂肪可以改善幼鱼和养成阶段斜带石斑鱼的生长性能,且对体成分、生化指标和消化代谢酶活性有一定影响;以SGR、FCR和PER为评价指标,幼鱼和养成阶段的斜带石斑鱼对饲料中脂肪的需要量均在11%~13%内。     

新加坡石斑鱼虹彩病毒ORF086蛋白的原核表达、纯化及抗体制备

新加坡石斑鱼虹彩病毒(Singapore grouper iridovirus,SGIV)是导致石斑鱼养殖严重经济损失的主要病原体。本研究构建了含有新加坡石斑鱼虹彩病毒(Singapore grouper iridovirus,SGIV)ORF086基因的重组表达质粒载体pET32a-ORF086,将其转化到大肠杆菌中进行融合表达,经SDS-PAGE分析和Western blot鉴定,证实重组大肠杆菌融合表达了SGIV ORF086蛋白。经异丙基-β-D-硫代半乳糖苷(isoprophl-thio-β-D-galactopyranoside,IPTG)浓度、诱导温度、诱导时间等诱导表达条件的优化,确定在0.7 mmol/L IPTG、16℃诱导14 h时可溶性SGIV ORF086重组蛋白占重组蛋白的60%。经镍琼脂糖凝胶柱纯化重组蛋白,纯化度达95%以上。用纯化的SGIV ORF086蛋白免疫小鼠,获得了高效特异的SGIV ORF086抗血清。     

利用畜禽加工副产品替代点带石斑鱼饲料中的鱼粉

比较网葙养殖点带石斑鱼对宠物级鸡肉粉(简称P-PBM)和一种畜禽蛋白混合物(由饲料级鸡肉粉、羽毛粉和血粉按质量比65:20:15的比例混合而成,简称MM)的利用能力.设5组等蛋白(49％粗蛋白)、等能(19 MJ· kg-1总能)饲料:对照饲料中添加50.0％鱼粉,在其余4组饲料中分别加入15.0％、30.0％的P-PBM或13.9％、27.8％的MM替代对照饲料中鱼粉的30％、60％,每个饲料处理设3个网箱重复,每个网箱中放养30尾鱼[初始体质量(33.4土0.1)g],饲养实验持续10周.结果表明:通过添加P-PBM或MM将点带石斑鱼饲料中鱼粉含量降低到20.0％对鱼摄食、增质量、饲料系数、氮储积效率(NRE)、磷储积效率(PRE)和鱼体组成无明显的不良影响;利用P-PBM部分替代鱼粉后鱼生长速度趋于加快,NRE和PRE趋于升高.本实验结果证实P-PBM是点带石斑鱼的优质饲料蛋白源,将其与鱼粉搭配使用可提高网箱养殖点带石斑鱼的生长性能和食物利用效率.     

First Documentation of Male Sexual Maturation in Captivity of Pacific Goliath Grouper,Epinephelus quinquefasciatus

This is the first documentation of male sexual maturation in captivity of Pacific goliath grouper. Males weighed between 15.3 and 16.6 kg and measured 93.5 and 97 cm in total length. No mature females were found during the same 4-year period of observation in captivity.     

Viral susceptibility,transfection and growth of SPB – a fish neural progenitor cell line from the brain of snubnose pompano,Trachinotus blochii (Lacépède)

This study investigates the susceptibilities of the SPB cell line to fish viruses including giant seaperch iridovirus (GSIV‐K1), red sea bream iridovirus (RSIV‐Ku), grouper nervous necrosis virus (GNNV‐K1), chum salmon reovirus (CSV) and eel herpesvirus (HVA). GSIV‐K1, RSIV‐Ku and CSV replicated well in SPB cells, with a significant cytopathic effect and virus production. However, the cells were HVA and GNNV refractory. To examine the ability of SPB cells to stably express foreign protein, expression vectors encoding GNNV B1 and B2 fused to enhanced green fluorescent protein (EGFP) and GSIV ORF35L fused to DsRed were constructed and introduced by transfection into SPB cells. Stable transfectants displayed different morphologies compared with SPB and with each other. EGFP‐B1 was predominantly localized in the nuclei, EFPF‐B2 was distributed throughout the cytoplasm and nucleus, and granular 35L‐DsRed was localized with secreted vesicles. The expression of EFPF‐B2 in SPB cells produced blebs on the surface, but the cells showing stable expression of EGFP, EGFP‐B1 or 35L‐DsRed showed normal morphologies. Results show the SPB cells and the transfected cells grow well at temperatures between 20 and 35 °C and with serum‐dependent growth. SPB cells are suitable for studies on foreign protein expression and virology.