Effects of graded levels of dietary myo‐inositol on non‐specific immune and specific immune parameters in juvenile Jian carp (Cyprinus carpio var. Jian)

The aim of this study was to evaluate the effects of myo‐inositol (MI) on non‐specific immune and specific immune defence in fish. A total of 1050 Jian carp (Cyprinus carpio var. Jian) (22.28±0.07 g) were randomly distributed into seven groups, of three replicates each, of feeding diets containing graded levels of MI (163.5, 232.7, 384.2, 535.8, 687.3, 838.8 and 990.3 mg MI kg^?1 diet). After a 60‐day growth trial, an infectious trial was conducted by injection of Aeromonas hydrophila for 17 days. Results showed that the red blood cell (RBC) and the white blood cell count were significantly increased with increasing MI levels up to 535.8 mg kg^?1 diet (P<0.05). The spleen index showed a tendency similar to RBC, whereas the head kidney index showed the inverse pattern (P<0.05). The phagocytic activity of leucocytes, haemagglutination titre, lysozyme activity, anti‐A. hydrophila antibody titre and immunoglobulin M, after being injected with A. hydrophila, were all improved with an increase in the MI levels up to 232.7–687.3 mg kg^?1 diet respectively (P<0.05). Myo‐inositol did not influence serum acid phosphatase activity and total iron‐binding capacity (P>0.05). These results suggested that MI could enhance non‐specific immune and specific immune responses in fish.     

Induced ovulation of yellow catfish (Pelteobagrus fulvidraco) using a combination of a gonadotrop‐releasing hormone analogue and domperidone

The effects of an intraperitoneal hormone injection of gonadotropin‐releasing hormone agonist (D‐Ala⁶, Pro⁹‐NEt GnRHa) alone or in combination with a dopamine antagonist, domperidone (DOM), on ovulation induction in yellow catfish Pelteobagrus fulvidraco were tested. The hormone treatments were as follows: 6 mg kg⁻¹ body weight (BW) of carp pituitary extract as a positive control, GnRHa 10, 20, 40 and 80 μg kg⁻¹ BW and a combination of GnRHa and DOM as follows: 10 μg+5 mg, 20 μg+10 mg, 40 μg+20 mg and 80 μg+40 mg kg⁻¹ BW. Physiological saline (0.7% NaCl) was used as a negative control. Significant differences in the ovulation ratio, latency period and ovulation index (OI) were observed among treatments (P<0.05). The combination of GnRHa and DOM at doses of 40 μg+20 mg kg⁻¹ BW had higher values of the ovulation ratio and OI, and a shorter latency period compared with other treatments. The highest OI in GnRHa treatments was only 56.67%, suggesting a dopaminergic tone on gonadotropin secretion in this fish at the pre‐ovulatory stage. Therefore, ovulation can be successfully induced in yellow catfish with 40 μg kg⁻¹ GnRHa+20 mg kg⁻¹ DOM without affecting the egg quality.     

不同饲料原料对草鱼生长和肌肉品质的影响

分别以专用配合饲料、浸泡蚕豆、浸泡豌豆喂养体质量为(1540.9±57.5)g的草鱼(Cteno-pharyngodon idellus)90d,以考察不同原料对草鱼生长和肌肉品质的影响。结果表明,配合饲料组、浸泡蚕豆组和浸泡豌豆组草鱼的增重率分别为17.3%、13.7%和12.2%,饵料系数分别为5.00、4.09和5.08,三种原料对草鱼的脏体比、肝体比没有显著影响;与普通草鱼相比,三种原料组草鱼肌肉粗脂肪含量和肌肉失水率显著降低(P0.05),胶原蛋白含量和肌原纤维长度显著增加(P0.05)。上述结果表明,三种原料均可显著改善草鱼肌肉品质;与浸泡蚕豆组相比,专用配合饲料组显著提高了草鱼的生长性能。     

镉对鲤遗传毒性和外周血细胞数量的影响

将鲤(Cyprinus carpio)分别暴露于0.16、0.31、0.63、1.26 mg/L Cd2+溶液中,研究Cd2+对鲤外周血红细胞微核率、核异常率、红细胞和白细胞数量的影响,探讨Cd2+对鲤遗传毒性和外周血细胞数量影响的变化规律和趋势。结果显示:Cd2+对鲤红细胞微核率和核异常率的影响存在浓度-效应和时间-效应关系。与对照组相比,1.26 mg/L Cd2+组鲤在不同暴露时间的红细胞微核率和核异常率均极显著(P<0.01),核异常率在72 h显著(P<0.05)增加,72 h后表现为极显著(P<0.01)增加。Cd2+对鲤外周血淋巴细胞、单核细胞和嗜中性粒细胞比例的影响存在浓度-效应和时间-效应关系。相同Cd2+浓度下,鲤淋巴细胞比例随暴露时间增加先降低后上升,同一暴露时间淋巴细胞比例随Cd2+浓度增加而降低。相同Cd2+浓度下,鲤单核细胞和嗜中性粒细胞比例随暴露时间增加先升高后降低,同一暴露时间嗜中性粒细胞比例随Cd2+浓度增加而升高。研究表明,Cd2+对鲤具有遗传毒性效应,且随Cd2+浓度增加而增强。     

锦鲤成熟系数及个体生殖力的研究

对锦鲤(Cyprinus carpiod)的成熟系数和个体生殖力进行了研究。结果显示:雌、雄锦鲤成熟系数变化规律基本一致,成熟系数在5月下旬达到最高值。2+~5+龄锦鲤个体绝对生殖力F与其年龄A、体长L、体重W呈直线相关,回归方程分别为:F=67054A+61567(R2=0.8419,P<0.01),F=8588.4L+24969(R2=0.9217,P<0.01),F=315.33W-9688.8(R2=0.9631,P<0.01)。     

鲤头长、体厚、体高性状的QTL定位及遗传效应分析

用174个SSR、41个EST、345个SNP标记对以镜鲤良种后代为祖父母本所培育的杂交F2群体的68个个体进行基因型检测,运用JoinMap4.0软件包构建遗传连锁图。利用MapQTL5.0区间作图法(interval mapping,IM)和多QTL区间定位法(MQM mapping,MQM)进行QTL检测,通过置换实验(1000次重复)确定连锁群显著性水平阈值。在对体高、头长、体厚的区间定位中,共检测到6个与体高性状相关的QTLs区间,分布在LG1(SNP1339-SNP1490)、LG10(HLJE469-SNP1491)、LG12(SNP0922-HLJ1316)、LG13(SNP0937-HLJ328)、LG25(SNP1041-HLJ594)、LG35(SNP1425-SNP0389)等6个连锁群上,解释表型变异范围为20.0%～43.3%。其中,SNP1339-SNP1490区间LOD值最大为3.64,解释表型变异35.4%。6个与头长相关的QTLs,分布在LG1(SNP1339-SNP1490)、LG12(HLJ071-HLJ336)、LG13(SNP0937-HLJ328)、LG24(SN...     

芙蓉鲤鲫(芙蓉鲤♀×红鲫♂)的性腺组织学及繁殖性能研究

采用解剖观察、组织切片及人工催情等方法,研究芙蓉鲤鲫(Cyprinus capiofurong.♀×Carassius auratus red var.♂)的性腺发育及繁殖性能。结果显示:解剖观察,芙蓉鲤鲫性腺发育异常的个体占83.64%,性腺外观基本正常的个体占16.36%。组织学观察,芙蓉鲤鲫性腺可分三类:两性嵌合体占21.13%,其中以精巢为主的16.90%,以卵巢为主的4.23%,它们性腺发育迟缓,在繁殖季节成熟系数也没有明显变化,性腺多为一侧发育或两侧不对称,两种性腺细胞均不能成熟;雌性个体占40.84%,在生殖季节卵巢可发育到第IV时相,但未见其细胞核发生偏移;雄性个体,占38.03%,在生殖季节只能发育到精子细胞阶段,不能产生成熟的精子。经人工催产,芙蓉鲤鲫少部分个体有发情产卵行为但不能正常受精。结果表明芙蓉鲤鲫为两性败育类型。     

Investigations on the digestibility and metabolizability of the major nutrients and energy of maize leaves and barnyard grass in grass carp (Ctenopharyngodon idella)

In the uplands of northern Vietnam, culture of grass carp contributes significantly to income and household food security of Black Thai farmers. Maize is one of the most important upland crops and barnyard grass is the most important weed in the paddy rice fields. Thus, these are frequently used by small‐scale fish farmers as fish feed. An 8‐week feeding trial was conducted simultaneously in a recirculation and in a respirometric system to determine the digestibility and metabolizability of the nutrients of maize leaves and barnyard grass, to assess their crude protein, lipid and energy conversion and to estimate the energy allocation in grass carp. The following diets were used: diet ‘A’ (reference diet) containing 39% crude protein with 19.8 MJ kg^?1 gross energy; diets ‘B’, ‘C’ and ‘D’, which contained the same amount of the reference diet as the control diet, supplemented with a known amount of dried barnyard grass, dried maize leaves or fresh maize leaves, respectively. Five fish were assigned to each treatment in each experimental unit. Reference and test diets were fed to fish and faecal samples were collected and the oxygen consumption was measured in order to set up an energy budget of the fish over the whole experimental period. The weekly development of the body weight was recorded. The body weight gain of the fish fed diet D was significantly higher than that of the group fed diet A, which also in turn was significantly higher than that of fish fed diet B or C. The apparent digestibility coefficients (ADC) of nutrients and gross energy for the different experimental diets in fish kept in the aquaria were, for diets A, B, C and D respectively, 94.1%, 60.9%, 70.5% and 84.7% for protein, 91.3%, 60.7%, 76.8% and 71.8% for lipid; 95.9%, 44.5%, 60.6% and 69.1% for gross energy. The partial ADC of plant leaf ingredients were determined and barnyard grass and dried maize leaves were found to be not only poorly digestible but having negative impact on the digestibility of the reference diet, while fresh maize leaves were well digested. The results of the present study indicated that fresh maize leaves have a good potential to be used as supplement in diets for grass carp.     

两种鲤鲫杂交回交子代染色体核型分析及比较

采用PHA和秋水仙素体内注射制备两种鲤鲫杂交回交子代鱼（鲤鲫杂交♀×德国镜鲤♂；鲤鲫杂交♀×鲤♂）的染色体。结果表明：两种鲤鲫杂交回交子代染色体组由150条染色体组成，按着丝粒位置染色体组型可分为四组，每个染色体小组均由三条同源染色体组成。其中鲤鲫杂交♀×鲤♂回交的染色体数目为3n=150，染色体臂数NF=234，其核型公式为：3n=60m＋24sin＋36st＋30t；鲤鲫杂交♀×德国镜鲤♂回交染色体数目为3n=150，染色体臂数NF=258，其核型公式为：3n=63m＋45sin＋12st＋30t。     

鲢、鳙对三角帆蚌池塘藻类影响的围隔实验

以浙江金华汤溪威旺养殖基地的三角帆蚌养殖水体为研究对象,通过围隔实验比较研究了单养鲢、鳙和三角帆蚌的池塘浮游植物密度、生物量和优势种(属)组成等的差异,以及养蚌池混养鲢鳙对水体浮游植物密度、生物量以及优势种变化的影响。结果表明,养蚌(10#)围隔的浮游植物平均密度和生物量均显著高于高密度鲢(12#)围隔(P<0.05),其蓝藻数量及生物量显著高于高密度鲢(12#)和低密度鳙(13#)围隔(P<0.05),绿藻数量则显著低于低密度鲢单养(11#)围隔(P<0.05)。在鱼蚌混养的情况下,单养蚌(10#)围隔浮游植物平均数量显著高于鲢-蚌混养(15#,16#)和鳙-蚌混养(17#,18#)围隔(P<0.05),其蓝藻数量及生物量极显著高于鲢-蚌混养(15#,16#)或鳙-蚌(17#,18#)围隔(P<0.01),其绿藻数量显著低于混养高密度鲢(16#)或低密度鳙(17#)的混养围隔(P<0.05)。研究结果充分说明,鲢、鳙和三角帆蚌三者对水体藻类组成的影响有别,三角帆蚌养殖池中适当混养鲢或鳙可以有效控制蓝藻(铜绿微囊藻)的生长,促进绿藻(四尾栅藻)的生长,并最终有利于三角帆蚌的养殖,混养鲢密度的增加有利于控制藻类生长,而鳙密度的增加促进了裸藻等中大型藻类的生长。