硒对铜胁迫下大菱鲆幼鱼生长、抗氧化能力及相关基因表达的影响

为探讨硒对铜胁迫下大菱鲆幼鱼生长、抗氧化能力及相关基因表达的影响,以初始体质量为(24.85±0.10) g的大菱鲆为研究对象,通过在饲料中添加五水硫酸铜和亚硒酸钠,配制铜、硒含量分别为(0、0,1 000、0,1 000、2,1 000、4 mg/kg) 4种等氮等能的实验饲料,命名为D1、D2、D3和D4组。养殖实验持续84 d。结果显示:①各组间实验鱼成活率无显著差异;增重率、特定生长率和蛋白质效率均在D2组显著低于D1、D3和D4组;摄食率和饲料系数呈相反趋势,在D2组显著高于其他3组。②幼鱼全鱼和肝脏粗脂肪含量呈先下降后上升趋势;而背肌粗蛋白和粗脂肪含量在各组之间无显著性差异。全鱼、脊椎骨和肝脏中Cu含量在D2组达到最高值;Zn含量则在D4组达到最高值;肝脏中铁含量呈下降趋势,在D3和D4组显著低于D1和D2组。③D2组显著降低了幼鱼血清总抗氧化能力(T-AOC)、过氧化氢酶(CAT)和谷胱甘肽过氧化物酶(GSH-Px)活性;丙二醛(MDA)含量则呈相反趋势,在D2组显著高于D3和D4组;总超氧化物歧化酶(T-SOD)和铜—锌超氧化物歧化酶(CuZn-SOD)活性均在D4组达到最低值。④血清谷丙转氨酶(ALT)、谷草转氨酶(AST)活性均在D2组显著高于其他3组;而血糖浓度、总胆固醇(TC)、高密度脂蛋白胆固醇(HDL-C)和低密度脂蛋白胆固醇(LDL-C)活性均在D2组达到最低值,显著低于D1组。⑤肝脏金属硫蛋白(MT) mRNA相对表达量在D4组达到最高值,显著高于其他3组;谷胱甘肽转移酶(GST)和溶菌酶(LZM) mRNA相对表达量均在D2组显著低于其他3组;热休克蛋白70 (HSP70) mRNA相对表达量则在D2组显著高于其他3组。综上所述,在本实验条件下,饲料中添加硒(2～4 mg/kg)可缓解高铜(1 000 mg/kg)胁迫导致的鱼体生长缓慢等症状,并可调控鱼体的抗氧化能力、生理代谢及相关基因表达量,进而对鱼体在高铜胁迫下的内环境稳态恢复具有一定的促进作用。     

Effect of Dietary Antarctic Krill Meal on Growth Performance,Muscle Proximate Composition,and Antioxidative Capacity of Juvenile Spotted Halibut,Verasper variegatus

A 7‐wk feeding trial was conducted to evaluate the effects of dietary Antarctic krill meal (AKM) on the growth performance, proximate composition of muscles, and antioxidative capacity of juvenile spotted halibut. Six diets were formulated to contain about 50% protein and 8% lipid. A control diet (R0) without AKM and the other five diets with 8.1, 16.2, 24.3, 32.4, and 42.5% AKM supplementation (R10–50) to replace 10, 20, 30, 40, and 50% fishmeal protein were used to feed to juvenile spotted halibut. The juveniles were fed with each diet using three replicates and cultivated in the indoor culture system. Results showed that the specific growth rate, feed intake, and protein efficiency ratio in the R30 and R40 groups were significantly higher than that in other groups (P < 0.05). Survival rate in the R50 group was significantly lower compared with the R0 group and the other four AKM supplementation groups. Moreover, the rising AKM levels in diets had significant effects on the chemical composition of juvenile spotted halibut, showing significantly decreased contents of crude protein, but increased lipid and ash contents (P < 0.05). The total superoxide dismutase activity and catalase activity of serum and liver in AKM groups were significantly higher than those in the control group (P < 0.05). In contrast, the contents of malondialdehyde in serum and liver were significantly lower compared with the control group. These findings illustrate that a moderate AKM level in diets can significantly improve the growth performance, feed utilization, and antioxidative capacity in juvenile spotted halibut, which support the finding that AKM may be used as a good protein source for halibut in the aquafeed industry.     

中国深远海养殖发展方式研究

在渔业转型发展进程中,发展深远海养殖是突破生态环境和自然资源约束性挑战,实现新时期中国海水养殖业可持续发展的战略方向。基于联合国粮食及农业组织(FAO)关于深远海养殖发展的定义,结合中国海水养殖业发展水平和海域条件,对中国深远海养殖概念进行了界定。提出养殖品种选择、养殖系统构建、养殖海域规划是关系深远海养殖产业稳步有序发展的重要因素。在养殖品种选择方面,应重点考虑经济潜力、适应水温和养殖技术;在养殖系统构建上,分析比较了不同养殖系统应用于深远海养殖的适宜性、安全性和经济性;在养殖海域规划方面,应重点考虑养殖排放、环境承载力和海域条件。     

Reforming the European Common Fisheries Policy: a case for capacity and effort controls

I summarize the total allowable catch (TAC) fishery management system, which forms part of the European Common Fisheries Policy (CFP) as complicated, inaccurate and ineffective. Total allowable effort (TAE), i.e. limits on fishing capacity and days‐at‐sea, provides a simpler, readily enforceable control to protect all species affected by a fishery. Fishing capacity of vessels in each region‐gear fleet could be capped through limits on engine power, gear, crew, and fittings, and/or reducing allowances of days‐at‐sea for large, powerful vessels. Two basic, fishery‐dependent indicators are put forward to assess sustainability of a fishery dependably even in the absence of fishery‐independent data. One is socio‐economic, the other is ecological. Fishery working groups within each marine region would recommend a TAE to sustain their fishery while also protecting the most critically affected species or processes. Regional working groups would supervise a consistent approach across the different fisheries in their region. A pan‐European group would set policy, implement external agreements, set rules for trading TAE if necessary and harmonize fishing opportunities across regions. To ease negotiations on TAEs with the fishing industry when an ecosystem needs to recover, I propose compensation payments funded by re‐direction of existing CFP subsidies that promote fishing.     

种青养鱼模式下的草鱼肌肉营养成分和品质特性

为探究种青养鱼养殖模式对草鱼肌肉营养成分和品质特性的影响,随机选取以种青喂草为主养殖模式下养殖的草鱼(生态草鱼)和投喂人工配合饲料进行养殖的草鱼(饲料草鱼)各16尾,测定其肌肉系水力和质构特性指标,以及肌肉常规营养成分、矿物元素、氨基酸和脂肪酸含量。结果显示,生态草鱼和饲料草鱼肝体比和空壳率无显著性差异;生态草鱼肌肉系水力指标中滴水损失显著低于饲料草鱼,冷冻渗出率不显著地低于饲料草鱼,失水率不显著地高于饲料草鱼,p H值无显著性差异;肌肉的硬度、弹性、凝聚性、胶黏性和回复性均无显著性差异;生态草鱼粗脂肪含量显著低于饲料草鱼,水分、灰分、粗蛋白含量均无显著性差异;生态草鱼P和Fe含量均显著高于饲料草鱼,Mg、Mn和Cr含量均极显著高于饲料草鱼;生态草鱼和饲料草鱼肌肉氨基酸组成基本一致,均含有17种氨基酸,其中人体必需氨基酸总量分别为6.85%和6.27%。生态草鱼必需氨基酸指数(EAAI)为76.07,而饲料草鱼为77.29,饲料草鱼略高于生态草鱼。生态草鱼和饲料草鱼肌肉均含19种脂肪酸,其中棕榈酸、花生四烯酸(ARA)、亚油酸(LA)、油酸、二十二碳六烯酸(DHA)和硬脂酸含量较高,为主要脂肪酸,而花生五烯酸(EPA)+DHA含量分别为8.95%和10.70%,且差异显著。研究表明,生态草鱼和饲料草鱼在肌肉质构特性方面无显著性差异,与饲料草鱼相比,生态草鱼具有肌肉系水力强、低脂肪和矿物元素含量高的特点。     

The Effects of Light Salting on Physicochemical Characteristics of Frozen Cod (Gadus morhua) Fillets

Abstract

The effects of light salting by brine injection and brine immersion on physicochemical and textural properties of cod fillets were evaluated. Light salting significantly increased yield and water holding capacity. Adding brine injection to the process can be used to shorten the process time needed to obtain the desired salt content and increase yield. The effects on chemical composition were most significant in salt content, but water and protein content were also affected. Water content decreased from the tail to head direction of the fillets, both in unsalted and light salted fillets. Changes in protein content were in opposite proportion to changes in water content. This could be seen in the fresh fish and also after freezing, both in unsalted and light salted fillets. Texture of the fish was not significantly affected by salting and freezing.     

浅海筏式养殖系统贝类养殖容量研究进展

据报道,以世界人均耕地计,中国人口以４亿为合适,按人均粮食５００ｋｇ／年计,中国人口以６亿为适度,按水资源来估算中国适度人口可为７亿。综合起来考虑,中国理想人口数量应在６．５亿左右［刘大椿等１９９５］,而我国实际人口已远远超过此数。很显然,只依靠耕地...     

Polygalacturonase and β-galactosidase activities in Hayward kiwifruit as affected by light exposure,maturity stage and storage time

Softening process and total antioxidant activity were evaluated in kiwifruit differently exposed to light intensity and harvested at two different times (October 10 and November 14). Fruit was stored for 2 months at 0 °C (S1) and then maintained for a week at ambient temperature (S2). The results showed that fruit harvested later presented a faster softening rate during storage than fruit harvested earlier, even if antioxidant activity did not change. Light-exposed fruit showed higher flesh firmness than that of shaded ones. Polygalacturonase activity was higher in kiwifruit maintained for a week at ambient temperature after cool storage and, in particular the highest value was recorded in fruit harvested later. The behaviour of β-galactosidase was different: it did not show changes in fruit harvested later and significantly decreased in light- and shade-exposed fruit harvested earlier.     

Evaluation of fertilizing capacity of cryopreserved rainbow trout sperm

ABSTRACT:   Experimental insemination was performed using artificially produced low-motility sperm. A mathematical model was applied to the results of the insemination in order to clarify the relationship between sperm motility, the density of sperm and the fertilization rate of eggs. In the model, the probability of fertilization by individual spermatozoa was a function of sperm density in the insemination solution. The results showed that the probability of fertilization clearly decreased with increased sperm density, and the maximum possible fertilizing rate by increasing the sperm density was constrained by the proportion of motile sperm (% motility). The model was also applied to the results of insemination tests of cryopreserved sperm in order to evaluate the fertilizing capacity of cryopreserved sperm. It was proven that cryopreserved sperm needed a higher density to obtain the maximum fertilization rate compared with fresh sperm, and it was anticipated that the ratio of the motile inseminated cryopreserved sperm should be more than 5.0% to achieve an egg fertilization rate greater than 90%.     

饲料中花生四烯酸含量对刺参生长性能、抗氧化能力及脂肪酸代谢的影响

为探究饲料中添加花生四烯酸(arachidonic acid,ARA)对刺参(Apostichopus japonicus)生长性能、抗氧化能力及脂肪酸代谢的影响,选用初始体重为(10.78±0.06)g的刺参为研究对象,以鱼粉和发酵豆粕为主要蛋白质源,小麦粉为主要糖源制作基础饲料,通过在基础饲料中添加不同比例的ARA-纯化油,制成ARA含量分别为0.02%(对照组)、0.17%、0.36%、0.51%、0.59%和0.98%(占饲料干重)的6组等氮等脂的实验饲料,在室内循环水养殖系统进行为期56 d的养殖实验。结果表明,随着饲料中ARA含量的升高,刺参增重率(weight gain rate,WGR)呈先上升后降低的趋势,0.36%和0.51%ARA饲料组刺参WGR显著高于其他处理组(P0.05),刺参的特定生长率(specific growth rate,SGR)和饲料效率(feed efficiency,FE)与WGR具有相同的变化趋势;刺参体壁粗脂肪含量随饲料ARA含量升高呈先降低后升高的趋势,在0.51%ARA饲料组含量最低,且显著低于对照组与0.98%ARA饲料组(P0.05);同时,随饲料中ARA含量的提高,刺参体壁中ARA和n-6多不饱和脂肪酸(n-6 polyunsaturated fatty acids,n-6 PUFA)含量呈显著上升趋势,而二十碳五烯酸(eicosapentaenioc acid,EPA)、二十二碳六烯酸(docosahexaenoic acid,DHA)和n-3多不饱和脂肪酸(n-3 polyunsaturated fatty acids,n-3 PUFA)含量显著降低(P0.05);抗氧化能力方面,0.36%和0.51%ARA饲料组刺参肠道中超氧化物歧化酶(superoxide dismutase,SOD)、过氧化氢酶(catalase,CAT)和总抗氧化能力酶(total antioxidant capacity enzyme,T-AOC)活性均显著高于对照组与0.98%ARA饲料组(P0.05),而肠道丙二醛(malondialdehyde,MDA)含量呈相反的变化趋势(P0.05);刺参肠道中脂肪酸合成酶(fatty acid synthase,FAS)和乙酰辅酶A羧化酶(acetyl-Co A carboxylase,ACC)活性随饲料ARA含量的升高呈显著降低趋势(P0.05);刺参肠道中肉毒碱棕榈酰转移酶-1(carnitine palmitoyltransferase-1,CPT-1)活性随饲料ARA含量升高呈先升高后降低的趋势(P0.05)。研究表明,在本实验条件下,饲料中添加适量ARA(0.36%~0.51%)能够对刺参生长、抗氧化能力起到一定的促进作用,同时结果显示,饲料ARA含量会对刺参肠道内脂肪酸代谢产生一定的影响。