鱼类细胞工程育种技术和原理（三）

四、性反转 (一)鱼类的性别 自然界的鱼类性别多种多样，有些种类为雌雄异体，其外形和体色都明显不同；有些种类是雌雄同体，或雄性先成熟或雌性先成熟，人们所熟知的黄鳝即是先雌后雄的鱼类。     

知鱼、识鱼、管鱼:从个性研究开始

个性是指个体随着时间的推移, 在不同情境下所表现出的持续一致的行为差异, 普遍存在于动物界中。在种或种群水平, 个性表现为行为集, 即相关联行为的集合, 在行为集内, 每个个体有其行为类型。个性包含 5 个个性轴: (1)害羞-大胆性; (2)探索-回避性; (3)活动性; (4)攻击性; (5)社交性。个性影响着鱼类的行为表现, 从而影响鱼类的生命过程和产出, 对鱼类自身福利, 水产增、养殖, 渔业管理等都具有十分重要的意义。本文简要介绍了鱼类个性的研究进展和鱼类个性的在水产增养殖、捕捞、渔业资源管理及保护以及物种入侵防治等方面的应用, 并对存在的问题进行了分析以及展望了今后的研究方向, 旨在为鱼类个性的研究及应用提供参考。     

鱼类肠道组织结构、功能、影响因素及其保护物质的研究进展

肠道可以吸收营养物质并抵御病原体、微生物和细菌毒素进入内部环境，因此在鱼类健康中起着重要作用。作为鱼类与外部环境接触面积最大的器官，肠道受到多种因素的侵害，严重制约了鱼类的健康生长。文章从鱼类肠道组织结构、肠道的屏障功能、引起肠道损伤的因素以及有效缓解肠道损伤的物质等四个方面进行综述，可为进一步了解鱼类肠道健康的分子机制及相关产品的研发提供参考。     

鄱阳湖湿地内湖鱼类若干性状分析

初步调查了冬季鄱阳湖湿地内湖鱼类资源现状及其体长、体重等性状数据,分析其生长特征。结果表明,鲤鱼、鲫鱼是湖区鱼类的优势种,四大家鱼数量和质量上都呈减少趋势;鱼类个体呈小型化和低值化态势,渔业资源面临一定压力。加强保护区渔业监测与巡护,争取生态补偿,改变湖区居民经济产业结构或能利于鄱阳湖渔业发展。     

四带小鲃胚胎发育及系统进化分析

四带小鲃是一种具有较高经济价值的小型热带观赏鲤科鱼类。本实验利用光学显微镜观察了其胚胎发育全过程,采用小鱼游泳法和流式细胞术检测了其染色体数目及DNA含量,最后利用线粒体基因组序列对其在鲃亚科中的系统进化地位进行了分析。结果显示,水温28°C条件下,四带小鲃的胚胎发育经历了卵裂前期、卵裂期、囊胚期、原肠期、神经胚期、器官形成期和出膜期7个时期,24 h孵化出膜。与斑马鱼出膜时开始形成色素不同,四带小鲃出膜时色素未形成,这有利于早期器官形成和发育的观察。以公鸡血细胞DNA含量2.30 pg/2c为标准,四带小鲃DNA含量为1.50 pg/2c。四带小鲃染色体为2n=50,系统进化树显示,四带小鲃在鲃亚科鱼类进化史上属于较早出现的鱼类,染色体数为原始的数目类型,鲃亚科其他属的鱼类独立发生多倍化。上述结果为四带小鲃的繁殖和遗传改良研究提供了基础资料。     

三峡水库小江流域常见鱼类肌肉碳、氮、磷生态化学计量特征

为探究三峡水库小江流域常见草食性、浮游生物食性、肉食性和杂食性鱼类肌肉的碳(C)、氮(N)、磷(P)生态化学计量特征,2018年1月(枯水期)和7月(丰水期)在小江流域7个设定断面,采集4种食性的14种鱼类样品,测定其生长特性指标,分析鱼类肌肉C、N、P生态化学计量特征及相关性。结果表明,鱼类肌肉C、N、P元素含量为34.75%～58.71%、7.00%～15.45%、0.89%～8.21%,C:N、C:P和N:P为3.62～9.75、16.92～136.95、2.14～35.31,其中磷元素含量变化最大且是导致N:P变化的主要原因。小江流域不同食性鱼类肌肉元素组成差异不明显,其中仅草食性鱼类、浮游生物食性鱼类的N含量和N:P显著大于肉食性鱼类和杂食性鱼类(P<0.05),其他元素及比例在各食性鱼类之间均无显著性差异(P>0.05);不同采样断面的鱼类肌肉元素含量及比例无显著性差异(P<0.05);相关性分析发现,小江流域鱼类肌肉N和P含量呈负相关关系(P<0.05),除草食性外,各食性鱼类的N含量均与水体NO^-₃-N...     

翘嘴红鲔亲鱼运输、培育、繁殖注意事项

翘嘴红鲴俗称大白鱼，是我国四大淡水名鱼之一。肉质细嫩，味道鲜美，是我省重点发展的名特优鱼类品种，越来越受到广大养殖者和消费者的青睐。但因其属凶猛鱼类，性情急躁，多年来在运输、养殖、繁育等方面死亡率都很高。我所从2003年开始进行翘嘴红铂人工繁育试验。起初因亲鱼成熟度差等原因，常出现半产、难产现象。     

水源、水质对鱼类产品品质的影响

俗语讲“鱼儿离不开水”,鱼类终生生活在水中,水源、水质对鱼类始终产生着影响。水源、水质的优劣直接影响着鱼类产品的品质甚至健康和生命。 一、产生影响的理论依据 由于鱼类终生生活在水中,水体中的水生动植物、细菌、有机质、无机盐、溶解气体的含量和数量以及水温、透明度等理化特证,生物特征都与鱼类     

鱼类体色研究进展

鱼类的体色丰富多彩,这是由于鱼类体内具有色素细胞所致,鱼类的基本色素细胞有四种：即黑色素细胞（Melanophore）、虹彩细胞（Iridocyte,又称鸟粪素细胞,guanophore）、红色素细胞（Erythrophore）和黄色素细胞（Xanthophore）。色素细胞都具有薄而极富弹性的细胞膜,膜上有细微的肌纤维和神经末梢。     

海水鱼产销、加工及品质控制调查分析

我国海水鱼品种繁多,优选出产量高、销量好、产地较广、价格适中的鱼类品种,能为以后鱼类的相关研究正确选用研究对象提供参考依据。鱼类是人类的优质蛋白食物,含有人体必需脂肪酸,是人们喜欢的营养食物。但因其蛋白和水分含量高,易腐败变质失去食用价值甚至危及消费者     

Functional palatability enhancer improved growth,intestinal morphology,and hepatopancreas protease activity,replacing squid paste in white shrimp,Litopenaeus vannamei,diets

Squid visceral paste is a popular attractant and feeding stimulator supplement in shrimp feeds in China, but it often faces problems with fluctuating availability, cost, composition, and quality. An 8‐week experiment was performed to test a proprietary palatability enhancer as an alternative to squid paste in white shrimp feed. Seven diets were tested: a control diet with no supplementations; S1 and S3 diets supplemented with squid paste at 1 or 3%, respectively; S1+PE0.1 and S1+PE0.15 supplemented with both 1% squid paste and the palatability enhancer at either 0.1 or 0.15%, respectively; and finally PE0.1 and PE0.15 supplemented only with the palatability enhancer at 0.1 or 0.15%, respectively. The results showed a trend for increased feed intake and weight gain when squid paste was added to the diet compared to the control, but this was worsened by raising the inclusion level from 1 to 3%. The inclusion of the PE, in combination with squid paste or alone at 0.15%, led to a significantly higher growth, and a feeding stimulation effect was also indicated, with PE0.1 and PE0.15 having a higher feed intake than the control. A further beneficial effect was a significant increase in protease activity in the hepatopancreas in the S1+PE0.15, PE0.1, and PE0.15 treatments compared to the control. In addition, a significant increase in the height of the intestinal mucosal folds was observed in PE0.15, followed by PE0.1. The results demonstrated the potential to replace or reduce squid visceral paste in shrimp diets by supplementing with a PE with functional effects beyond feeding stimulation.     

Effect of Salinity on Embryonic Development,Hatchability, and Growth of African Catfish,Clarias gariepinus,Eggs and Larvae

Abstract

Effects of salinity on embryonic development and growth of African catfish, Clarias gariepinus, eggs and larvae were studied. Eggs were incubated at 27-29°C in 2,4,6,8, and 10 ppt sodium chloride. Rate of embryonic development was delayed in all salt solutions by 15, 15,28 and 30 minutes, in 2,4,6, and 8 ppt sodium chloride, respectively, when compared with the control group (0% salt); total mortality occurred at 12 hours after gastrula stage in the 10 ppt concentration. Percentage hatching was 45.1,47.7, 59.5,49.2, and 26.6% while percentage deformity was 10.4, 16.1, 52.0, 28.6, and 71.6% in 0, 2, 4, 6, 8, and 10 ppt salt treatments, respectively. There were significant differences (P <0.05) in the hatching percentage and in deformity percentage between 4, 6, and 8 ppt. Rate of yolk absorption was significantly faster in the control and 2 ppt salt treatments, but slower in 4, 6, and 8 ppt. Rate of increase in length was slower with increasing salinity. The optimum salinity for African catfish eggs and was between 0-2 ppt and acceptable up to 6 ppt. The results suggest that increasing salinity delayed hatching and development of African catfish eggs and larvae, respectively, as well as increased the deformity of the larvae.     

Surface disinfection of Pacific threadfin, Polydactylus sexfilis, and amberjack, Seriola rivoliana, eggs

The effects of exposing the eggs of Pacific threadfin and amberjack eggs (AEs) to different concentrations of hydrogen peroxide for 5 min on hatch rate and survival were assessed in a series of experiments using a petri dish model rearing system. Despite significant inter‐batch variation in hatch rate, it was shown that eggs of both species could be safely exposed to up to 11 340 mg L⁻¹ H₂O₂ for 5 min. Exposure to 34 230 mg L⁻¹ H₂O₂ for 5 min was shown to be lethal to AEs at a late stage of development. In two further experiments, it was demonstrated that Pacific threadfin eggs were resistant to all tested concentrations of a range of polyvinylpyrrolidone iodine (PVP‐I) concentrations and contact times (up to 1000 mg L⁻¹ PVP‐I for 10 min). The level of bacteria adhering to the eggs of both species was highly variable. Where eggs were heavily colonized (>10⁴ cfu egg⁻¹), hydrogen peroxide concentrations of at least 11 340 mg L⁻¹, or PVP‐I concentrations higher than 500 mg L⁻¹ for 10 min, were required for effective sterilization. In less colonized batches, rinsing in sterile seawater or exposure to lower (550 mg L⁻¹) concentrations of H₂O₂ was sufficient to result in high apparent levels of surface sterility (<1 cfu egg⁻¹).     

斑节对虾的精氨酸、蛋氨酸、苯丙氨酸、色氨酸的需求量研究

用额外添加必需氨基酸的实验饲料投喂斑节对虾虾苗，研究斑节对虾的精氨酸，蛋氨酸，苯丙氨酸，色氨酸的需求量。添加精氨酸，对虾的增重明显，并且随着添加量的增大，对虾的增重率也变大，但不影响成活率，当精氨酸占饲料中蛋白质含量１０．３８％时，对虾的增重率，成活率都最高，这时饲料的必需氨基酸比率（Ａ／Ｅ）与对虾肌肉必需氨基酸比率相似。添加蛋氨酸后，对虾的增重率，成活率明显升高，烂尾率明显下降至消失，但三个水平     

Seasonal distribution, age, growth, and reproductive biology of marbled sole Pleuronectes yokohamae in Tokyo Bay, Japan

ABSTRACT:   The seasonal distribution, age, growth and reproductive biology of marbled sole Pleuronectes yokohamae (Günther) from Tokyo Bay, Japan were studied. A clear seasonal distribution trend was observed, with P. yokohamae limited to the south of the bay in summer and expanding almost throughout the bay in other seasons. The formation and dynamics of hypoxic areas in the bay limited the northward distribution of P. yokohamae in summer. Age was determined by counting growth rings on otoliths; maximum ages were found to be 5 years for males and 6 years for females. The mean back-calculated length for females at each estimated age was greater than that for males. Growth of males and females was shown by the von Bertalanffy growth equations. Reproductive biology was studied on the basis of gonadosomatic indices and histological sections of gonads. The spawning season lasted from November to March, peaking in December and January. Sixty per cent of males at 1 year and all males ≥ 2 years had mature testes, whereas 6.7% of females at 1 year, 58.3% of females at 2 years, and all females ≥ 3 years had attained maturity.     

Factors influencing the abundance of the common bully, Gobiomorphus cotidianus McDowall, in small, North Island, New Zealand, lakes

Adult common bullies, Gobiomorphus cotidianus McDowall, are small (total length =  30–120 mm), benthic fish commonly found in the littoral zones of New Zealand lakes where they are a major prey species for trout and eels. Differences in their relative abundance (CPUE) were determined between 21 shallow North Island lakes. Mean CPUE ranged from 2 to >  1000 fish net^{− 1} night^{− 1} and was inversely related to water transparency. The abundance of bullies was not reduced in lakes containing rainbow trout, Oncorhynchus mykiss (Walbaum), but was reduced in all lakes containing self-recruiting populations of eels, Anguilla spp. Mean densities of planktonic larval bullies in the limnetic zone were also inversely related to water transparency. Since low water transparency is related to increased trophic status for these lakes, the abundance of bullies is likely to be related to lake productivity, rather than turbidity.     

Growth,Feed Utilization,and Glycemic Response in European Sea Bass,Dicentrarchus labrax,Juveniles Fed Carbohydrate of Different Complexities

The effect of dietary carbohydrate complexity on growth, feed utilization, and glycemia was studied in European sea bass juveniles. Four isonitrogenous (50% crude protein) and isolipidic (15% crude lipids) diets were formulated to contain 20% pregelatinized maize starch (PGS diet), dextrin (DEX diet), maltose (MAL diet), or glucose (GLU diet). No effect of dietary carbohydrate complexity on growth was noticed. Feed efficiency and protein efficiency ratio were lower in fish fed the GLU diet than in the other groups, whereas the opposite was observed for feed intake. Plasma glucose peaked 3–4 h after feeding in fish fed the MAL and GLU diets, whereas in fish fed the PGS and DEX diets the peak was reached 5–6 h after feeding. Peak plasma glucose concentration (13 mmol/L) was higher in fish fed the GLU diet than the other diets (9 mmol/L). Shorter hyperglycemia duration was observed in fish fed the MALT and GLU diets (6 h) than the PGS and DEX diets (10 h). Complex carbohydrates delayed plasma glucose concentration peak compared with simple sugars, whereas the opposite was observed for hyperglycemia duration. Overall, dietary maltose, dextrin, and starch were apparently better utilized as energy source than glucose by European sea bass juveniles.     

Occurrence and Effects of the Rhizocephalan Parasite,Polyascus gregarius,in the Chinese Mitten Crab,Eriocheir sinensis,Cultured in a Freshwater Pond,China

An epizootic outbreak of the parasitic barnacle, Polyascus gregarius, was reported for the first time in cultured commercial mitten crab, Eriocheir sinensis. Observations were made in a freshwater culture pond in Shenjia Dang, Zhejiang province, China, from June to October 2007. The surface morphology and appearance of the interna, externa, or scar of P. gregarius were recorded in 1464 crabs, including 871 males and 593 females. Overall prevalence of infection was 37.8 and 31.7% in male and female crabs, respectively. The monthly variation of infection was mainly dependent on the mortality of the host, with the highest prevalence (58.0% of males and 51.3% of females infected) in June, and the lowest (13.4% of males and 6.3% of females) in October. A host with multiple externae or scars was encountered frequently, with the maximum of 28 externae or 19 scars on a single crab. Being restricted in the culture pond, the hosts could not escape and return to the brackish water of the estuary; therefore, the externae were never exposed to male cyprids and remained unfertilized. As a result, all the externae degenerated and dropped off finally after 2–3 mo. This parasite caused castration, anecdysis, and increased mortality in the host, and therefore, had both direct and indirect effects on the commercial culture of E. sinensis. Infected males were castrated and displayed morphological modifications of secondary sexual characters. The size of infected crabs was significantly smaller than that of uninfected crabs because the molting was reduced by infection. After all the externae dropped off, the scarred host crabs finally died. A high mortality (possibly >50%) due to parasitism was observed in this study.     

Use of xylocaine, potentiated with sodium bicarbonate, as an anaesthetic for fry and juveniles of acumara, Algansea lacustris Steindachner 1895, from Lake Patzuaro, Michoacan, Mexico

Abstract. The effectiveness of xylocaine anaesthesia, potentiated with sodium bicarbonate, was investigated on the altiplano cyprinid, Algansea lacustris Steindachner. The drug gave excellent sedation, handling and recovery and was effective at doses between 50 and 300 mg/l in 1 g/l sodium bicarbonate.     

Yield, growth and mortality rate of the Thai river sprat, Clupeichthys aesarnensis, in Sirinthorn Reservoir, Thailand

The Thai river sprat, Clupeichthys aesarnensis Wongratana, is a clupeid with a short life span, and supports artisanal fisheries in a number of reservoirs in the Mekong Basin. The growth parameters, mortality rates and the status of the Thai river sprat in Sirinthorn Reservoir (28 800 ha), NE Thailand (15°N; 105°E), are presented. The fishery is based on lured lift‐nets, operated 7–14 days in the new moon period, September to April each year. It was shown that the von Bertalanffy growth function (VBGF) model was L_t (mm) = 78.43[1 ? exp{?0.211[t ? (?0.7996)]}] and its growth conformed to an isometric pattern. Natural mortality rate (month^?1) was 0.13 month^?1. Total mortality rates ranged from 0.69 to 1.53 month^?1 depending on the weather and the fishing season. Recruitment was continuous throughout the year but peaked in June and July. The yield per recruit model indicated that the exploitation rate of this fishery is probably too high.