Effects of Salinity on Na~+-K~+-ATPase Activity in Gills,and Concentrations of Ions and Hormones in Serum of Juvenile Turbot(Scophthalmus maximus)

采用饲养试验方法,研究了平均体质量为(7.16±0.07)g的大菱鲆(SCOPHTHAlMuS MAXIMuS)幼鱼分别在盐度12、18、24、30和36下饲养60 d后,其鳃nA+-k+-ATPASE活力、血清离子浓度、生长激素(gH)、皮质醇激素(COr)、特定生长率(Sgr)和饲料效率(fCE)的变化。结果表明:幼鱼鳃nA+-k+-ATPASE活力、血清nA+浓度均随盐度的升高而上升,分别在3.48~8.30 u/Mg和169.99~180.00 MMOl/l之间,其中12盐度组最低,36盐度组最高。幼鱼血清中k+和Cl-浓度分别在2.20~3.47 MMOl/l和136.67~142.00 MMOl/l之间,各盐度组之间差异不显著。幼鱼血清中gH和COr浓度分别在0.41~1.66 ng/Ml和35.33~76.41 ng/Ml之间;其中gH在36盐度组最高,12盐度组最低,而COr在12盐度组最高,36盐度组最低。幼鱼Sgr和fCE分别在(1.45~2.00)%/d和1.12%~1.38%之间,与盐度的相关性不显著,两者均为12盐度组最低。由此可见,盐度变化显著影响大菱鲆幼鱼鳃nA+-k+-ATPASE活力、血清nA+浓度和激素含量。本研究对大菱鲆养殖生理生态条件分析具有重要参考意义,研究结果可为大菱鲆养殖的盐度选择提供理论依据。The Na+-K+-ATPase activity in gill,concentrations of ions and hormones in serum,and specific growth rate and feed conversion efficiency of juvenile turbots( Scophthalmus maximus)( body weight of 7.16 ±0.07 g),which have been reared at salinities 12,18,24,30 and 36 for 60 days,were investigated.The results showed that Na+-K+-ATPase activity and Na+concentration were 3.48- 8.30 U /mg and 169.99-180.00 mmol /L,respectively,and their levels increased with the rise of water salinity.The highest values were observed at salinity 36,and lowest ones at salinity 12.The Na+-K+-ATPase activity and Na+concentration inthe fish reared at salinity 12 were significantly lower than those in the control( P 0.05).Growth hormone and cortisol levels were 0.41- 1.66 and35.33- 76.41 ng /ml,respectively.Growth hormone level was the lowest in the fish reared at salinity 12,and the highest at salinity 36,both of which had significant difference compared to that of the control( P 0.05).Specific growth rate and feed conversion efficiency were( 1.45-2.00) % /day and 1.12%- 1.38%,respectively.Although both were the lowest at salinity 12,they were not significantly correlative with salinity.Thus,the results indicate that the changes in salinity could have significant impacts on Na+-K+-ATPase activity in gill,concentrations of Na+,growth hormone and cortisol in serum of juvenile turbots.The results provide important reference for salinity selection in turbot mariculture.现代农业产业技术体系专项资金(No.CARS-50

Effects of salinities on muscle amino acid and fatty acid composition of juvenile turbot(Scophthalmus maximus)

为了探讨盐度对幼鱼肌肉中氨基酸和脂肪酸组成的影响,作者将平均体质量为(7.16±0.07)g的大菱鲆(SCOPHTHAl MuSMAXIMuS)幼鱼分别饲养在盐度(12、18、24、30(对照组)和36)水体中60 d。结果表明,不同盐度下,幼鱼肌肉中的氨基酸总量(TAA)、必需氨基酸(EAA)总量、非必需氨基(nEAA)总量和呈味氨基酸(fAA)总量分别在69.25%±0.37%~74.85%±1.26%、31.70%±0.11%~33.74%±0.28%、31.29%±0.44%~34.60%±1.26%和24.20%±0.66%~26.98%±1.02%,从高到低依次为36组>30组>12组>18组>24组,36组均显著高于24组(P0.05)。必需氨基酸指数(EAAI)在40.41±1.23~44.46±0.54,30和36组显著大于其他组(P30组>24组>12组>18组,各盐度组间均无显著性差异(P>0.05)。必需脂肪酸(EfA)总量在3.28%±0.04%~3.58%±0.10%,各盐度组间均无显著性差异(P>0.05)。饱和脂肪酸(SfA)总量在27.51%±0.37%~29.83%±0.35%,12组显著高于36组(P salinity 30 > salinity 12 > salinity 18 > salinity 24, and those of fish reared at salinity 36 were significantly higher than those of fish maintained at salinity 24(P0.05).The essential amino acid index(EAAI) was 40.41±1.23~44.46±0.54, increasing with the rise of water salinity.The EAAI of fish reared at salinities 30 and 36 was significant higher than those of other salinity groups(P salinity 30 > salinity 24 > salinity 12 > salinity 18, all of which had no significant differences between groups(P>0.05).The essential fatty acids(EFA) content was 3.28%±0.04%~3.58%±0.10%, no significant differences were observed between groups(P>0.05).The saturated fatty acids(SFA) content was 27.51%± 0.37%~29.83%±0.35%.The EFA in fish maintained at salinity 12 was significant higher than that of fish reared at salinity 36(P<0.05).Therefore, the qualities of free amino acid and fatty acid in muscles of fish reared at salinity 36 had been greatly improved in comparison with those of the control(salinity 30).This study provides important references for mechanistic researches on energy metabolisms of osmoregulation and salinity selection in turbot mariculture.国家现代农业产业技术体系建设专项资金资助项目(CA-RS-50

Effects of salinities on growth and flesh quality of juvenile turbot( Scophthalmus maximus)

将平均体质量为(7.16±0.07)g的大菱鲆幼鱼分别饲养在不同盐度(12、18、24、30和36)的水体中60 d,以探讨盐度对幼鱼特定生长率、生长激素、成活率、摄食率、饲料效率和肌肉营养成分的影响。结果表明:大菱鲆幼鱼在盐度分别为18、24、30和36的水体中均生长良好,成活率为100%,特定生长率分别为1.97、1.87、1.87和2.00%/d;在盐度为12的水体中,幼鱼的成活率和特定生长率均显著低于盐度30组(对照组)(P0.05)。幼鱼特定生长率随血清生长激素和饲料效率的升高而增大,与盐度的相关性不显著。幼鱼肌肉中的粗蛋白质含量随水体盐度的升高而降低,除盐度12和18组之间无显著性差异外(P>0.05),其余各盐度组之间均存在显著性差异(P0.05);各盐度组之间幼鱼肌肉中的水分均无显著性差异(P>0.05)。综上所述,适当降低盐度可改善大菱鲆幼鱼生长和肌肉品质,其适宜盐度为18。The specific growth rates(SGR),growth hormone(GH),survival rate,feed intake ratio,feed conversion efficiency(FCE) and body composition in muscles of juvenile turbot(Scophthalmus maximus) [body weight of(7.16±0.07)g],which had been reared at salinities 12,18,24,30 and 36 for 60 days, were investigated.The results showed that the SGR of the fish reared at salinity 18,24,30 and 36 were 1.97, 1.87,1.87 and 2.00 %/d,respectively,with a survival rate of 100% for these groups(P>0.05).However, the SGR and survival rate of the fish reared at salinity 12 were 1.45 %/d and 80.77%,respectively,both of which had significant differences in comparison with those of the control(salinity 30)(P0.05).Although SGR had not significantly correlative with salinity,SGR increased with the rise of FCE and GH.The crude protein decreased with the rise of water salinity and showed significant difference between groups(P0.05).Thus,the results indicated that the changes in salinity could have significant impacts on SGR,GH,FCE,feed intake ratio and protein in muscles of juvenile turbot.Rearing in brackish water can enhance grow th performance and flesh quality of the fish,and the proper salinity is 18.The results from this study provide important reference for salinity selection in turbot mariculture.鲆鲽类产业技术体系专项(CARS)(2060302-2-1-008

Characterization of the Mx and hepcidin genes in Epinephelus akaara asymptomatic carriers of the nervous necrosis virus

Emarked Fund for Modern Agro-industry Technology Research System [nycytx-50]; Minjiang Scholar ProgramInnate immunity plays a key role against the nervous necrosis virus (NNV) before adaptive immunity kicks off during fish development. We have studied the interferon-inducible Mx and the antimicrobial peptide hepcidin genes to probe the status of innate immunity in red-spotted grouper, Epinephelus akaara larvae and juveniles. For this study we examined the NNV infections in the farmed E. akaara, to generate the complete coding sequences of Mx and hepcidin, and to characterize the expression during development. Red-spotted grouper NNV (RGNNV) was mainly detected in the brain, gills and heart of the sick groupers, and the larvae from 0 to 23 day-post hatching (dph) of the farmed asymptomatic groupers were detected RGNNV-positive using real-time PCR (RT-PCR). The open reading frame (ORF) of E. akaara Mx gene is 1878 bp long encoding a putative protein of 626 amino acids, while the ORF of hepcidin is 258 bp in length encoding 86 amino acid residues. An RT-PCR was optimized to estimate the expression patterns of Mx and hepcidin in E. akaara. Mx was constitutively expressed in head kidney, liver, spleen, heart, gills, muscle, brain, thymus and intestine, and it was first detected on 2 dph and increased to a higher level after 15 dph. Hepcidin was mainly expressed in the liver and intestine, and it was detected in the fertilized-egg showing and significantly increased expression after 29 dph. It could be hypothesized that the farmed groupers are RGNNV carriers, promoting vertical virus transmission from parents to the offspring, as the eggs were tested RGNNV positive. We can conclude that there should be a balance between the innate immunity and the RGNNV infection during early development, and RGNNV will outbreak when the innate immunity becomes weak and adaptive immunity is still immature. (C) 2013 Elsevier B.V. All rights reserved