Inbreeding evaluation using microsatellite and its effect on growth traits in turbot,Scophthalmus maximus

Turbot is an economically relevant fish, and simultaneously at the risk of inbreeding depression in China. Microsatellite DNA markers were used to evaluate inbreeding level of a random turbot breeding population and further investigate its effects on growth traits. DNA based inbreeding coefficients (F_DNA) were ranged from 0 to 0.4124. Average inbreeding coefficient was 0.0621 with a standard deviation of 0.0658. Regression analysis results showed inbreeding had a very significant (p < .01) effect on harvest body weight (BW) and significant (p < .05) effect on harvest body long (BL). Inbreeding depression, expressed as the percent change in phenotype per 10% increase in F, was ?4.00% for BW and ?1.14% for BL. The inbreeding depression on high inbreeding coefficient (more than 10%) individuals was further analyzed. A set of significant (p < .05) and larger inbreeding depression was obtained, ?7.15% and ?2.49% for BW and BL respectively. This study demonstrates that inbreeding has a negative effect on growth traits and highlights the need of DNA markers to control inbreeding and maximize the genetic diversity in selection breeding programs.     

The tolerance and safety assessment of taurine as additive in a marine carnivorous fish,Scophthalmus maximus L.

The effects of dietary taurine on growth performance, liver and intestine morphology, serum physiological and antioxidant parameters, serum thyroid hormone level, muscle taurine content and fatty acid composition of turbot were first evaluated, for the safe utilization in marine fish feed and for human food safety. Four experimental diets were formulated to contain 0, 10, 50 and 100 g/kg taurine. Each diet was randomly assigned to six replicates of 30 juvenile turbot (initial mean weight of 7.46 g). The feeding trial lasted for 10 weeks. The growth performance of fish was significantly enhanced by 10 g/kg dietary taurine. The integrity of the distal intestine was impaired and the absorptive surface was found to be significantly reduced by 100 g/kg dietary taurine. The obvious pathological changes in liver were observed in fish fed 100 g/kg taurine. Dietary taurine with 10 and 50 g/kg significantly increased the activities of serum superoxide dismutase, lysozyme and thyroid hormone. The taurine content in muscle was found to be significantly increased by dietary taurine; however, no significant differences were observed among taurine‐supplemented treatments. This study suggested that 10 g/kg taurine was safe in turbot feed, and fivefold of safety margin was obtained.     

Growth and survival of young turbot (Scophthalmus maximus L.) produced with cryopreserved sperm

This study assessed the growth and survival over a year of two groups of 4‐month‐old turbot Scophthalmus maximus (L.) derived from artificial fertilization with fresh (FG) and cryopreserved sperm (CG). Growth in both groups, measured monthly in terms of length and weight, were compared. Survival was also recorded. No significant differences were found when we compared weight and length data in both groups. Growth rates were similar between FG and CG young turbot during 1 year. Likewise, the same survival rate (92.2%) was found in both groups. Our results show the good survival and growth of young turbot obtained from cryopreserved sperm, and confirm the cryopreservation technique as a useful tool for raising turbot for commercial purposes.     

饲料脂肪源对大菱鲆幼鱼生长性能和肌肉脂肪酸组成的影响

以不同脂肪源配制成等氮等脂的7种试验饲料,对体重为(27.31±0.10)g的大菱鲆幼鱼进行40 d的饲养试验,旨在探讨饲料脂肪源对大菱鲆幼鱼生长性能和肌肉脂肪酸组成的影响。7种试验饲料的脂肪源分别为鱼油、豆油、菜籽油、花生油、猪油、鱼油+豆油(鱼油∶豆油=1∶1)和鱼油+豆油+猪油(鱼油∶豆油∶猪油=3∶4∶3)。每种饲料设3个重复,每个重复12尾鱼。结果表明:鱼油+豆油组的增重率和特定生长率显著高于鱼油组、豆油组和菜籽油组(P0.05),花生油组、猪油组和鱼油+豆油+猪油组的增重率和特定生长率则显著低于其他各组(P0.05)。饲料系数以鱼油+豆油组最低,猪油组最高。各组干物质和总磷表观消化率差异不显著(P0.05),猪油组和鱼油+豆油+猪油组的粗脂肪表观消化率显著低于其他各组(P0.05)。花生油组、鱼油+豆油组和豆油组的粗蛋白质表观消化率显著高于猪油组(P0.05)。摄食不同脂肪源饲料的大菱鲆幼鱼鱼体水分、粗脂肪和粗灰分含量差异不显著(P0.05)。猪油组鱼体粗蛋白质含量显著低于菜籽油组、花生油组和鱼油组(P0.05),其余各组间无显著差异(P0.05)。除C14∶0以外,各组大菱鲆肌肉中的脂肪酸含量和相应饲料中脂肪酸含量呈正相关。大菱鲆幼鱼肌肉中n-3多不饱和脂肪酸(PUFA)含量以鱼油组和鱼油+豆油组较高,而以花生油组和猪油组较低。结果提示:豆油和菜籽油是大菱鲆幼鱼饲料良好的脂肪源,鱼油和豆油按1∶1混合添加则能使大菱鲆幼鱼更好地生长。     

菜籽油替代鱼油对大菱鲆幼鱼生长、脂肪酸组成及脂肪沉积的影响

本试验旨在研究饲料中菜籽油替代鱼油对大菱鲆(Scophthalmus maximus L.)幼鱼生长、脂肪酸组成以及脂肪沉积的影响。以菜籽油分别替代0、33.3%、66.7%和100.0%的鱼油,配制4种等氮等脂实用饲料。选择初始体重为(5.89±0.02)g的大菱鲆幼鱼420尾,随机分为4组,每组3个重复,每个重复35尾。每种饲料随机投喂1组试验鱼,养殖周期为92 d。结果表明:1)随菜籽油替代水平的升高,大菱鲆幼鱼的终末体重和特定生长率均有下降的趋势,而肝体比则有升高的趋势,其中全菜籽油组的终末体重和特定生长率显著低于全鱼油组(P0.05),肝体比则显著高于全鱼油组(P0.05)。菜籽油替代水平并未显著影响大菱鲆幼鱼的存活率、饲料效率、摄食率和表观净蛋白质利用率(P0.05)。2)菜籽油替代水平并未显著影响大菱鲆幼鱼的体成分、肌肉脂肪含量以及饲料脂肪表观消化率(P0.05),但显著影响了大菱鲆幼鱼的肝脏脂肪含量(P0.05)。66.7%菜籽油组和全菜籽油组肝脏脂肪含量显著高于全鱼油组(P0.05)。3)肝脏和肌肉脂肪酸组成与饲料脂肪酸组成呈正相关关系;相对于全鱼油组,66.7%菜籽油组和全菜籽油组肌肉和肝脏中C18∶2n-6(亚油酸)和α-C18∶3n-3(α-亚麻酸)含量显著升高(P0.05),而C20∶5n-3(EPA)和C22∶6n-3(DHA)含量显著下降(P0.05)。综上可知,从营养品质角度考虑,在大菱鲆幼鱼饲料中菜籽油替代鱼油水平应低于66.7%     

饲料脂肪源对大菱鲆生长、体组成及血清生化指标的影响

本试验以不同脂肪源配制成等氮等脂的7种饲料,对大菱鲆[(27.31±0.10)g]进行40 d的饲养试验,旨在探讨不同饲料脂肪源对大菱鲆生长、体组成、血清生化指标的影响。7种饲料分别添加6%的鱼油(FO)、大豆油(SO)、菜籽油(RO)、花生油(PO)、猪油(L)、鱼油-豆油(1∶1)(FSO)和鱼油-豆油-猪油(3∶4∶3)的混合油(MIX)。每组饲料设3个重复,每个重复12尾鱼。研究结果表明:(1)鱼油-豆油组特定生长率显著高于其他各组,较鱼油组(基础饲料组)提高了10.42%(P < 0.05),猪油组特定生长率最低,较鱼油组降低了19.79%(P < 0.05)。猪油、混合油、花生油组饲料系数分别较鱼油组提高了36.36%、33.33%、25.25%(P < 0.05),其余各组间无显著差异(P > 0.05);(2)饲料脂肪源对大菱鲆鱼体水分、粗脂肪和粗灰分含量影响不显著(P > 0.05),猪油组粗蛋白质含量显著低于鱼油组、菜籽油组和花生油组,其中较鱼油组降低了4.47%(P < 0.05)。摄食不同脂肪源饲料的大菱鲆空壳、内脏和背肌的脂肪含量差异不显著(P > 0.05),猪油组空壳的水分显著高于菜籽油组和混合油组(P < 0.05);(3)各试验组总胆固醇、甘油三酯、高密度脂蛋白胆固醇和碱性磷酸酶含量无显著差异(P > 0.05)。猪油组和混合油组的谷丙转氨酶含量显著高于其他各组,较鱼油组分别升高了124.89%和119.94%(P < 0.05),混合油组的谷草转氨酶含量显著高于其他各组,较鱼油组提高了352.51%(P < 0.05),表明猪油组和混合油组鱼体肝脏受到一定程度的损伤。综合以上7种饲料脂肪源对鱼体生长性能、体组成及血清生化指标的影响,鱼油-豆油(1∶1)、豆油和菜籽油可作为大菱鲆饲料合适的脂肪源,而猪油、混合油不适宜作为大菱鲆的饲料脂肪源。     

家禽副产物酶解肽部分替代鱼粉对大菱鲆生长性能、消化指标和特异性免疫指标的影响

本试验旨在研究家禽副产物酶解肽部分替代鱼粉对大菱鲆生长性能、消化指标和特异性免疫指标的影响。选取初始体重(10.32±0.26) g、大小均匀、体质健壮的大菱鲆450尾,随机分为5组,每组3个重复,每个重复30尾。首先配制含50%鱼粉的基础饲料,然后用家禽副产物酶解肽分别替代基础饲料中0(对照)、8%、16%、24%和32%的鱼粉,配制5种等氮等能的试验饲料,分别记为D0、D8、D16、D24、D32组。试验期为56 d。结果显示:家禽副产物酶解肽替代8%和16%的鱼粉对大菱鲆的增重率、存活率、特定生长率、饲料系数、肝体比、肥满度、脏体比等生长性能指标均无显著影响(P>0.05)。家禽副产物酶解肽替代鱼粉比例超过8%时,全鱼粗脂肪含量显著低于对照组(P<0.05)。D0、D8、D16组干物质表观消化率、粗蛋白质表观消化率和粗脂肪表观消化率显著高于D24、D32组(P<0.05)。D0、D8组肝脏中胃蛋白酶、胰蛋白酶活性显著高于D16、D24、D32组(P<0.05)。D0、D8组的血浆和肝脏中谷丙转氨酶、谷草转氨酶活性显著低于D24、D32组(P<0.05)。D8组血浆中补体3、补体4含量显著高于D24、D32组(P<0.05)。D0、D8组血浆中尿素氮、丙二醛含量显著低于D24、D32组(P<0.05)。D0、D8组的血浆中总抗氧化能力、超氧化物歧化酶活性以及总蛋白、甘油三酯、总胆固醇、葡萄糖含量显著高于D32组(P<0.05)。由此可见,在本试验条件下,以生长性能为基础,综合考虑消化、代谢、特异性免疫等指标,家禽副产物酶解肽替代大菱鲆饲料中鱼粉的适宜比例为8%。     

The effect of ultrafiltered fish protein hydrolysate levels on the liver and muscle metabolic profile of juvenile turbot (Scophthalmus maximus L.) by 1H NMR‐based metabolomics studies

A ¹H NMR‐based metabolomics approach was to explore the effect of ultrafiltered fish protein hydrolysate (UF) levels on the liver and muscle metabolic profile of juvenile turbot (Scophthalmus maximus L.). Fish protein hydrolysate (FPH) was produced from by‐products by enzymatic treatment, and UF was obtained by diluting FPH followed filtration. Fish were fed diets containing fish meal protein, which was, respectively, replaced by UF protein 0, 50, 100, 150 and 200 g kg^?1 of dietary total protein (UF‐0, UF‐5, UF‐10, UF‐15 and UF‐20) for 68 days. OPLS‐DA of liver and muscle showed that high levels of UF in diets may lead to corresponding tissue metabolites changes. In liver tissue, changing metabolites included dimethylamine, N,N‐dimethylglycine, valine, isoleucine, leucine, arginine and alanine and were mainly involved in choline metabolism and amino acid metabolism. For muscle tissue, changing metabolites included lactate, alanine, proline, fumarate, tyrosine, histidine, cystathionine and taurine. And the metabolites were mainly involved in glycolysis and gluconeogenesis, proline metabolism and taurine metabolism. ¹H NMR‐based metabolomics is a useful approach to investigate different levels of UF on metabolic profile in liver and muscle tissues combined with the growth.     

Construction and expression of DNA vaccine against reddish body iridovirus and evaluation of immune efficacy in turbot (Scophthalmus maximus)

Turbot aquaculture is a very important industry in China. However, it is hampered because of viral reddish body syndrome (VRBS) and high mortality caused by piscine turbot reddish body iridovirus (TRBIV). TRBIV virus is an icosahedron‐like and cytoplasmic DNA virus, belonging to Iridoviridae, Megalocytivirus. In previous studies, we have identified two antigen mimotopes using bioinformatics and constructed prokaryotic expression vectors. In this study, a fragment of major capsid protein (MCP) gene with the two antigenic epitopes was cloned into eukaryotic expression vector pVAX1, to generate a recombinant plasmid pVAX1‐TRBIV‐MCP. The plasmid DNA was transferred into turbot cell line TK using liposome, and transient expression was detected using RT‐PCR. After injection into turbot (Scophthalmus maximus), the expression of the antigen gene was analysed using RT‐PCR and was shown to express in all tested tissues in vaccinated fish 2 and 7 days post‐vaccination. The cumulative mortalities in the vaccinated and unvaccinated control fish were 30% and 88% respectively. Immune responses and upregulation of the expression of chemokine receptor, tumour necrosis factor, interferon and interferon‐induced antiviral molecules were observed in the vaccinated fish 60 h post‐vaccination. These results demonstrate that the vaccinated turbots had higher survival rate and produced specific serum antibodies following the TRBIV challenge. More studies are needed to develop and apply the promising DNA vaccine for virus control in turbot.     

大菱鲆迟缓爱德华氏菌福尔马林灭活疫苗研究

以大菱鲆为免疫对象,采用0.5福尔马林灭活的方法,将迟缓爱德华氏菌制成全菌疫苗,验证了其具有可靠的安全性。以浸泡和注射两种免疫接种方法对养殖大菱鲆14d内进行2次免疫,第二次免疫后第10天,对免疫鱼和各自的对照鱼进行爱德华氏菌的人工感染试验,获得注射接种疫苗的大菱鲆对腹水病的免疫保护率为70,浸泡接种疫苗的大菱鲆对腹水病的免疫保护率为35。表明注射和浸泡接种迟缓爱德华氏菌全菌疫苗都能使大菱鲆对腹水病产生免疫效果,并且注射免役效果优于浸泡免疫。