三种鲇遗传多样性的RAPD分析

从40个10bp随机引物中筛选出22个用于大口鲇、鲇及其杂交F1代三个群体多样性分析,共检测到217个位点,在群体之间和个体之间都存在差异。群体内的遗传相似度分别为0.986、0.878、0.961,群体内平均遗传变异是0.112;大口鲇与杂交F1代、鲇与杂交F1代、大口鲇与鲇群体间的遗传相似度为0.731、0.615、0.423,群体间的平均遗传变异为0.888。鲇群体的遗传变异度和多态位点比例均高于大口鲇、杂交F1代。UPGMA系统树清晰反映个体间和群体间的相互关系。     

一例杂交鲇腐皮病的细菌分离鉴定和药敏试验

正杂交鲇养殖始于20世纪80年代,多为种间杂交,目前主养种类有大口鲇与鲇正反交、怀头鲇♀×鲇♂、胡子鲇♀×革胡子鲇♂。因其生长速度快、适应能力强、肉质优良等特点,受到广大民众的喜爱,在全国各地均有养殖。2019年11月,市场购回的杂交鲇养殖期间发生了腐皮病,死亡率高达100%。本文就该病例进行了病原的分离鉴定和菌株的药敏试验。一、临床检查     

大口鲇(♀)与鲇鱼(♂)的杂交试验

连续 2年进行大口鲇 (♀ )与鲇鱼 (♂ )的杂交系列试验 ,结果显示 :与对照组相比 ,杂交组受精率稍低 ,而孵化率、出苗率没明显差异 ,说明大口鲇 (♀ )与鲇鱼 (♂ )之间的杂交不存在繁殖障碍或繁殖障碍较小 ;杂交后代生长 (体重、体长 )与母本相近 ,通过配对样本t检验分析 ,差异不显著 (P >0 0 5 ) ,而与父本差异显著 (P <0 0 5 ) ,具有类似母本的快速生长的杂种优势。     

VIE标记和T型标记标志南方大口鲇的初步研究

正为了对剥隘库区增殖放流的南方大口鲇开展放流效果评估工作,采用可见荧光植入标记(VIE)和T型标记对其进行标记。笔者研究了VIE标记和T型标记对南方大口鲇的标志效果,旨在为南方大口鲇增殖放流的效果评估提供技术储备。一、材料与方法1.试验鱼试验鱼为南宁市水产良种场人工培育的南方大口鲇。试验鱼饲养于渔业站网箱养殖基地,养     

大口鲇的生物学特性及人工养殖技术

大口鲇(Silurus meridionalis Chen),原名南方大口鲇,俗称河鲇,大河鲇,主产于我国长江流域的大江河中,是一种以鱼为食的大型经济鱼类,常见个体重约2～5公斤,最大个体可达40公斤以上。它与分布很广的那种小个子鲇(俗称土鲇)是同属不同种。大口鲇肉质细嫩、味道鲜美。我所从1985年起即开始对其进行了移养驯化和池塘人工养殖试验。结果     

鲇、大口鲇及其杂交鲇的血型分析

用人的血型定型试剂分别测定了鲇、大口鲇和杂交鲇的血型,测得它们具有5种血型表现型,即NN、YY、NY、YN和YYN;建立了N血型系统,推测出它们由N0、N1和N23个复等位基因决定。     

2008～2010年渔业科技入户主导品种和主推技术（十二）

（十一）鲇鱼 【品种来源】我国养殖的鲇鱼,主要有大口鲇、怀头鲇、胡子鲇和革胡子鲇等种类。来自于我国野生资源驯化培育,如大口鲇、怀头鲇和胡子鲇等;或者来自于引进驯化培育,如革胡子鲇等。经济价值较高的有大口鲇和怀头鲇等。大口鲇分布于我国长江以南的各大江河水系,     

主推品种 鲇鱼

【品种来源】我国养殖的鲇鱼，主要有大口鲇、怀头鲇、胡子鲇和革胡子鲇等种类。来自于我国野生资源驯化培育，如大口鲇、怀头鲇和胡子鲇等；或者来自于引进驯化培育，如革胡子鲇等。经济价值较高的有大口鲇和怀头鲇等。大口鲇分布于我国长江以南的各大江河水系，以长江流域为主产区。     

渔民知识讲座: 我国十二种主要经济水产动物养殖指南(一)南方鲇

南方鲇(Silurus meridionalis Chen),又名南方大口鲇、大口鲇、河鲇,地方名鲇巴郎,属鲇形目、鲇科、鲇属、南方鲇种.     

投喂浮性膨化饲料与冰鲜鱼养殖南方大口鲇的效果对比

南方大口鲇（Silurus meridiondis chan,简称大口鲇）是一种经济价值较高的肉食性鱼类,在四川的简阳、双流、邛崃、西昌二滩等地养殖较多。目前主要是用冰鲜鱼来养殖,随着冰鲜鱼的数量减少,价格上涨,大口鲇的养殖成本不断增大，养殖户开始把目光投向了配合饲料。关于用配合饲料驯化、养殖大口鲶的效果已有报道，通威公司也一直致力于推广膨化饲料多年，为了更进一步直观比较冰鲜鱼与膨化饲料的效果，特于2008年6月11日～7月31日在养殖户处开展了投喂浮性膨化饲料与冰鲜鱼养殖南方大口鲇的效果试验。     

Carotenoid deposition in pen-reared salmonids fed diets containing oil extracts of red crab (Pleuroncodes planipes)

The rate of deposition of carotenoids in pen-reared coho salmon was investigated by the addition of known carotenoid levels to diets. The carotenoids added to the diets were derived from red crab (P. planipes), and a process is described for the preparation of a soya oil carotenoid concentrate. Using a 3-stage counter-current extraction process, extracts containing 155 mg/100 g oil were prepared from red crab (P. planipes). Oregon moist pellets containing 3, 6, and 9 mg carotenoid/100 g were prepared using these extracts and were fed to coho salmon (Oncorhynchus kisutch) for 120 days. The amount of carotenoid deposited in the flesh of the fish was related to the carotenoid content of the diet and to the weight of the fish. Fish fed diets containing 6 and 9 mg carotenoid/100 g for the same length of time contained 60% more flesh carotenoids than those fed 3 mg/100 g. In general, after 120 days of feeding, only those fish feeding on diets containing 6.0 and 9.0 mg carotenoid/100 g and weighing over 215 g were assessed as having good-to-excellent coloration. Analysis of the flesh showed that there was no correlation between its carotenoid and fat contents.     

投喂螺旋藻、雨生红球藻对螺蛳体内类胡萝卜素积累效果的研究

在6个62 cm×78 cm×50 cm的水箱中每箱投放5 kg规格为(2.69±0.21)g的螺蛳。选取螺旋藻(Spiruli-na)、雨生红球藻(Haematococcus pluvialis)两种富含类胡萝卜素的微藻,分别以每箱每天12 g、10 g的量投喂,并采用水循环和充气的方式维持藻粉在水中均匀分布。于投喂前及投喂后4、8、12天取螺蛳200 g左右,采用分光光度法测定类胡萝卜素含量。结果显示:投喂螺旋藻的螺蛳经过8 d喂养体内类胡萝卜素含量从42.5μg/g提高到69.1μg/g,并不再显著提高。投喂雨生红球藻的螺蛳在4 d后类胡萝卜素含量已达213.3μg/g,并进一步缓慢提高。该结果表明螺蛳适宜作为向中华绒螯蟹传递类胡萝卜素的中间载体。     

Correction of black tiger prawn (Penaeus monodon fabricius) coloration by astaxanthin

After two months of feeding a group of juvenile black tiger prawn (Penaeus monodon) with a commercial feed (CF), their external pigmentation changed from its normal greenish-brown to a light blue. This condition was thought to be induced by a carotenoid deficiency in the feed. Nutritional improvement and hence correction of this condition was attempted by adding 50 ppm astaxanthin (Roche Ltd^®) into one feed (AF) and 5% addition of brown algae (Chnoospora minima) into a second feed (BF). After four weeks of feeding, the prawns fed on AF reverted to their normal greenish-brown pigmentation. The carotenoids present in the BF feed increased carotenoid content in the prawns, but the levels were not high enough to correct the blue coloration. Analysis of carotenoid content in the shells of the groups showed 318%, 57% and 14% increase for AF, BF, and CF respectively, with 70–90% of the total carotenoid being in the form of astaxanthin. Deposition of astaxanthin was higher in the shell than in the flesh, with deposition in the flesh plateauing after two weeks, whilst deposition in the shell increased steadily.

The importance of these findings to the marketing of cultured shrimps is discussed.     

Population differentiation and temporal changes of carotenoid pigments and stable isotope ratios in the offspring of anadromous and non‐anadromous trout Salmo trutta

Trout (Salmo trutta) exhibit anadromous and non‐anadromous forms which are commonly sympatric. Offspring of the two forms can be separated by differences in characteristics such as stable isotope ratios and carotenoid pigments, which differ due to the influence of maternal resources. The rate of change in different characteristics due to freshwater feeding and the extent of differences between populations however remain unclear. Stable isotope (N and C) ratios and carotenoid pigment profiles were examined in the offspring of anadromous and non‐anadromous fish sampled at different times from six sites within the catchment of the River Tweed, UK. Both techniques were able to separate newly emerged fry successfully, with carbon isotopes distinguishing the forms better than nitrogen isotopes and zeaxanthin being the primary carotenoid pigment used to distinguish the offspring of different migratory forms. By 4 months, stable isotope ratios of the two forms were still distinct although both carbon and nitrogen ratios needed to be considered to distinguish the forms. Zeaxanthin levels were more variable and overlapped between the offspring of the two forms. There was significant variation between populations and over time in both isotope ratios and carotenoid composition. Comparison between the two techniques would suggest that stable isotopes are more effective for distinguishing between offspring of different forms as the distinctions are evident for longer. Population differences in isotope ratios could influence the extent to which the forms can be distinguished and need to be quantified more thoroughly to fully evaluate the technique.     

Concentration and Composition of Astaxanthin in Black Tiger Prawn Penaeus monodon Postlarvae Fed Artemia sp. Nauplii or Mauxia Shrimsp Acetes intermedius

Minced Taiwan mauxia shrimp Acetes intermedius , an alternative to brine shrimp Artemia sp. nauplii, has long been used as a principal or supplemental feed in prawn hatcheries in Southeast Asia and India. In this study, black tiger prawn Penaeus monodon postlarvae were fed with frozen brine shrimp nauplii (diet B) or minced Taiwan mauxia shrimp (diet M) for 4 wk to compare their astaxanthin concentration and composition, survival, and growth. Diet B contained two and a half times more total carotenoid (TC) than diet M, with canthaxanthin as a major (79%) carotenoid, but without astaxanthin, a predominant carotenoid in crustaceans. Of its TC in diet M, 55% was β-carotene and 17% astaxanthin. B-prawn (postlarvae fed with diet B) had a similar growth rate as M-prawn and twice the survival rate as M-prawn. The concentrations of total astaxanthin (TA), free astaxanthin (FA), astaxanthin monoester (MA), and astaxanthin di-ester (DA) in B-prawn were all higher than those in M-prawn. Except for FA, no reduction of TA, MA, or DA concentration during the feeding interval was found in B-prawn. However, concentrations of TA, FA, MA, and DA in M-prawn all decreased. TC content of the experimental diets had a greater influence on resulting prawn astaxanthin concentration and composition than carotenoid compositions of the diets.     

Lutein as a natural carotenoid source: Effect on growth,survival and skin pigmentation of goldfish juveniles (Carassius auratus)

This study aimed to evaluate the effect of lutein supplementation on growth, survival and skin pigmentation for goldfish juveniles. Four diets enriched with different carotenoid sources (lutein, astaxanthin, canthaxanthin and a combination of lutein and canthaxanthin) were compared to a control diet without carotenoid supplementation. The carotenoid inclusion level was standardized at 50 mg kg‐1 in all treatments. 240 goldfish juveniles (1.07?0.57 g) were cultivated in 30 aquariums (30L) during 84 days. The experimental design was completely randomized with five treatments and six replicates. The dietary inclusion of carotenoid pigments did not affect the growth and feeding efficiency of goldfish juveniles. Supplementation with lutein presented higher survival values when compared to the other treatments. Astaxanthin and canthaxanthin supplementation increased the concentration of carotenoids on the skin of goldfish juveniles in relation to the control treatment. For the fish fed with the diet containing lutein, the skin pigmentation was as efficient as astaxanthin and canthaxanthin, but did not differ from the control and combined treatment (canthaxanthin + lutein). The lutein supplementation (50 mg kg‐1) improved survival and promoted efficient carotenoid pigmentation on the skin of goldfish juveniles.     

How Apparent Digestibility of Carotenoids,Macronutrients, and Minerals are Differently Affected by Ration Level in Atlantic Salmon,Salmo Salar

The main objective of this field experiment was to investigate whether ration level affected utilization of carotenoids, macronutrients, and minerals in 1,300 g Atlantic salmon (Salmo salar) during rapid growth. Salmon fed ration levels of either 1.2% or 0.6% of biomass of a commercial diet supplemented with astaxanthin and canthaxanthin (37 and 39 mg kg^?1, respectively) in two consecutive 6-day feeding periods had carotenoid digestibility coefficients of 11.8% and 32.1% at the high and low feed rations, respectively. Thus, low carotenoid digestibility, but good macronutrient digestibility, may explain poor pigmentation and good feed conversion in rapidly growing salmon. Practical implications are illustrated.     

Response of rainbow trout (Oncorhynchus mykiss) to varying dietary astaxanthin/canthaxanthin ratio: colour and carotenoid retention of the muscle

Rainbow trout with an average initial weight of 160 g were fed during 42 days diets containing varied keto‐carotenoids astaxanthin (Ax)/canthaxanthin (Cx) ratio, as follows: Ax 100% : Cx 0%; Ax 75% : Cx 25%; Ax 50% : Cx 50%; Ax 25% : Cx 75% and Ax 0% : Cx 100%. Muscle colour and carotenoid muscle retention were studied. Colour parameter values for mixed astaxanthin–canthaxanthin‐fed fish were intermediate between those obtained for Ax 0% : Cx 100% fed fish group and for Ax 100% : Cx 0% fed fish group. Concerning muscle carotenoid retention, it has been observed that as the level of canthaxanthin in diet increased, the muscle total carotenoid retention decreased. In the mean time, as the level of canthaxanthin in diet increased, the muscle astaxanthin retention decreased while that of canthaxanthin increased. The results reported here provide further evidence of non‐beneficial effects in terms of muscle colour and muscle carotenoid retention of the use of varying dietary astaxanthin/canthaxanthin ratio for feeding rainbow trout compared to values obtained for astaxanthin‐only feed.     

Enhancement of non‐specific immune responses in common carp,Cyprinus carpio,by dietary carotenoids obtained from shrimp exoskeleton

The immunostimulatory role of carotenoid extract from shrimp processing discards was evaluated by feeding common carp fingerlings with a diet containing carotenoid extract for 21 weeks at 100 and 200 mg kg^?1 astaxanthin levels. Haemoglobin content was significantly (P < 0.05) higher in the blood of fish fed with carotenoid diet (>8.1 g dL^?1) compared with that from fish fed with carotenoid deficient diet (6.86 g dL^?1) and also leukocyte counts were higher (P < 0.05). No differences (P > 0.05) were observed in total serum protein, globulin level and albumin‐globulin ratio, but albumin content was higher (P < 0.05). Respiratory burst activity was significantly (P < 0.05) higher, the serum lysozyme activity almost doubled and the serum bactericidal activity was significantly increased when the fish were fed with diet containing 200 mg kg^?1 of astaxanthin but no significant differences were observed in serum trypsin inhibitory activity. There was a significant (P < 0.05) increase in leukocyte myeloperoxidase activity due to dietary carotenoids. Challenging fish with Aeromonas hydrophila after the feeding period resulted in 50% mortality in the control group while in the group fed with diet containing 100 mg kg^?1 astaxanthin, the mortality rate was 15%. No mortality and even symptoms of infection was not observed in the group fed with diet containing 200 mg kg^?1 of astaxanthin. The study indicated that carotenoid extract from shrimp processing discards can effectively be used as immunostimulants in aquaculture of carps and dietary carotenoids were found to enhance various immune defence mechanisms and also provide protection against the infection of pathogen A. hydrophila.     

Pigmentation of gilthead seabream, Sparus aurata (L. 1875), using Chlorella vulgaris (Chlorophyta, Volvocales) microalga

A feeding experiment was conducted over 9 weeks with seven groups of 30 (fish per group) unpigmented gilthead seabream, Sparus aurata (L. 1875) (initial mean weight = 145.2 ± 12.3 g). Three experimental diets were prepared by adding to a basal diet free of carotenoid (final pigment content of around 40 mg per kg feed): (i) a biomass of the carotenogenic Chlorella vulgaris (Chlorophyta, Volvocales); (ii) a synthetic astaxanthin; and (iii) a mixture (1:1) of microalgal biomass and synthetic astaxanthin. At 3‐week intervals, five fish were sampled from each tank for total carotenoids analysis in skin and muscle. The carotenoid pigments (total amount = 0.4%) identified in the carotenogenic alga were lutein (0.3%), β‐carotene (1.2%), canthaxanthin (36.2%), astaxanthin, free and esterified forms (55.0%), and other pigments (7.3%). Carotenoid pigments were significantly deposited in the four skin zones studied during the feeding trial: the forefront between the eyes, the opercule, along the dorsal fin and in the abdominal area. In the muscle, regardless of the astaxanthin source, the amount of carotenoids measured was very low (less than 1 mg kg^?1) and differences not significant. Moreover, no muscle pigmentation was evident, and there was no variation in the amount of carotenoid analysed in skin tissue, through the trial, for each treatment. It was concluded that supplementing the feed with C. vulgaris would be an acceptable practice in aquaculture to improve the market appeal of the gilthead seabream.