Effect of dietary carbohydrate‐to‐lipid ratios on growth performance,body composition,nutrient utilization and hepatic enzymes activities of herbivorous grass carp (Ctenopharyngodon idella)

Six isonitrogenous (390 g kg^?1) and isoenergetic (16.2 kJ g^?1) diets with varying carbohydrate : lipid (CHO : L) ratios (202.5–1.74), were fed to triplicate groups of 25 fish in indoor recirculation system. Over 8‐week‐growth trial, best weight gain (WG), specific growth rate, feed conversion ratio, protein efficiency ratio and protein production value (P < 0.05) were observed in fish‐fed diets with CHO : L ratio of 7.5. Fish fed either the lowest (1.7) or highest (202.5) CHO : L ratio tended to produce lower (P < 0.05) growth and feed conversion efficiencies. The values of viscerosomatic index, hepatosomatic index and intraperitoneal fat ratio increased as dietary CHO : L ratios decreased. There were no significant differences in whole body and liver crude protein among dietary treatments. Whole body and liver lipid increased as CHO : L ratios decreased. Plasma cholesterol and triacylglyceride levels increased linearly as dietary CHO : L ratios decreased. Activities of glucokinase and pyruvate kinase were stimulated by elevated levels of dietary carbohydrate; however, activities of lipase (LPS) and alkaline phosphatase were stimulated by elevated levels of dietary lipid. Based on a second‐order polynomial regression analysis of WG against dietary carbohydrate and lipid levels, 275 g kg^?1 of carbohydrate and 59 g kg^?1 of lipid, corresponding to a CHO : L ratio of 4.7, in a diet holding 390 g kg^?1 of crude protein and 16.3 kJ g^?1 of gross energy, proved to be optimal for grass carp. These results indicated that utilization of dietary lipid and carbohydrate was moderate in grass carp, but the fish were a little more capable of utilizing lipid compared with carbohydrate.     

长江草鱼群体MHC Class ⅡB的多态性和进化分析

克隆及测序草鱼(Ctenopharyngodon idella)长江3个群体的主要组织相容性复合体(MHC)Class II B基因编码β1和β2区的第2和第3个外显子及两个外显子之间的内含子,分析了草鱼MHC的进化模式和种群遗传结构。结果显示:实验共定义了34个等位基因,每条序列包括长为130~136 bp的第2个外显子,长为218 bp的第3个外显子以及长81~371 bp的内含子。序列分析揭示,第2个外显子有106个核苷酸变异位点(78%)和40个氨基酸变异位点(88%),而第3个外显子有100个核苷酸变异位点(45%)和41个氨基酸变异位点(56%),β1变异要大于β2区。用β1和β2区序列分别构建的邻接(NJ)系统树均显示5个具有高支持率的谱系,结合序列变异特点和内含子长度,推测草鱼至少存在5个MHC Class II座位。分别计算β1的肽结合位点(PBR)、非肽结合位点及β2的非同义替换率(dN)和同义替换率(dS),PBR的dN/dS为2.03(P<0.05),非肽结合位点和β2则小于1,表明草鱼MHC受到歧化选择作用。根据等位基因在群体中的分布频率作分子方差分析(AMOVA),得出FST为0.37%,提示长江草鱼MHC没有遗传分化。     

滁州鲫鱼食性的初步研究

对滁州鲫鱼的食性进行了调查研究。结果表明:滁州鲫是一种杂食性鱼,它的主要食物组成是轮虫、枝角类、桡足类、单胞藻类和有机碎屑等,随着体长的增长,食物中大型浮游动物、水生植物所占比例明显增加。对食物的摄食量上有季节性变化,在夏、秋两季摄食量最大,春季次之,冬季最少。     

谷氨酸铜对罗非鱼和草鱼生长性能血清生化指标和体组成的影响

为研究谷氨酸铜制剂对罗非鱼、草鱼的生长性能、血清生化指标和鱼体组成的影响，选用180尾罗非鱼、135尾草鱼，分别随机分为3个处理组，每组3个重复，每个重复20或15尾。在基础饲料中添加五水硫酸铜作为对照组（10 mg/kg），试验组添加谷氨酸铜（高、低剂量组分别为10、5 mg/kg，按铜离子计），饲养8周。结果表明：与对照组相比，谷氨酸铜高、低剂量组罗非鱼的增重率分别提高3.9%和5.8%，草鱼的增重率分别提高4.0%和5.9%；罗非鱼特定生长率分别提高1.9%和3.3%，草鱼分别提高2.5%和3.5%；罗非鱼和草鱼的平均饵料系数分别降低7.6%和3.7%。两种鱼的血清生化指标及体组成各试验组间均无显著差别（P＞0.05）。由此可见，日粮中添加适量谷氨酸铜可提高鱼体的生长性能，且效果优于五水硫酸铜。     

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.     

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。     

饲料蛋白质和能量水平对草鱼生长和鱼体组成的影响

采用3×3因子试验确定不同蛋白质和脂肪水平饲料对草鱼生长和鱼体组成的影响。初始平均体质量为0.75g的试验鱼放养在27个规格为85cm×35cm×95cm的网箱中,每箱放养50尾。日粮中的蛋白源、脂肪源和可消化碳水化合物源,分别采用鱼粉、豆油和糊精配制,日粮设3个粗蛋白水平,每个蛋白水平有3个能量水平饲养草鱼84d。结果表明MPLL组(粗蛋白为30%,粗脂肪为4%)的特殊生长率和蛋白质效率最高,饲料系数最低,但与LPML组(粗蛋白为25%,粗脂肪为6%)差异不显著;总的来看,脂肪含量在4%和6%时特定生长率和饲料系数以中蛋白质组(MP,30%)最高,脂肪含量在8%时特定生长率和饲料系数以低蛋白质组(LP,25%)最高,表明饲料脂肪水平对鱼的生长和饲料系数有显著影响。随着饲料可消化能的增加,鱼体的脂肪含量增加,而蛋白和灰分含量没有多大变化。综合饲料成本等因素,本试验初步确定草鱼幼鱼生长所需的最适蛋白水平为25%,DP/DE约为23.47mg·kJ-1。     

香辛料液对草鱼块保鲜效果的影响

根据淡水鱼存在的贮藏问题,就香辛料液对草鱼鱼块保鲜效果进行了初步研究。采用水浴浸提的姜蒜大料-黄酒复合液(甲液)和超声浸提的姜蒜大料—黄酒复合液(乙液)对新鲜草鱼鱼块进行处理,通过测定货架期草鱼鱼肉的游离水含量、pH值、挥发性盐基总氮(TVBN)以及感官评分,研究了香辛料液对草鱼块的保鲜效果。结果表明:复合液能够有效地保持鱼肉货价期感官品质,并能有效延缓pH值和TVBN值的升高,且超声浸提的乙液效果较为明显。     

鳙小卫星DNA的克隆

鳙基因组ＤＮＡ 经内切酶Ｓａｕ３ＡⅠ完全酶切后，与Ｂａｍ ＨⅠ－ ｐＵＣ１８ 质粒连接，转化ＤＨ５α后，获得９３３ 个重组体。用人源小卫星探针３３ ．１５ 对重组体进行原位杂交筛选，获得１４ 个阳性克隆，取其中的１ 个阳性克隆（ 即小卫星ｐＢＣ１７４） 作探针，与５ 尾鳙和４ 尾鲢基因组ＤＮＡ 杂交，能产生具有高度变异性的、个体特异性的ＤＮＡ 指纹图，表明克隆的鳙小卫星ｐＢＣ１７４ 可用于鱼类ＤＮＡ 指纹分析。     

草鱼_中华鳖淋巴细胞扫描电镜结构_省略_绵羊红细胞受体_CD_2_的检测

草鱼淋巴细胞表面扫描电镜结构特征为有孔穴且较为光滑、具短小细锥状突起；中华鳖淋巴细胞、胸腺细胞表面扫描电镜结构特征为凹凸不平、较为光滑；它们均以表面凹凸不平特征的占大多数。E花环试验的光镜和扫描电镜观察显示：草鱼淋巴细胞E花环形成不明显，而中华鳖淋巴细胞、胸腺细胞的成花率分别为25％－34％和36％－47％，能形成花环的淋巴细胞、胸腺细胞以表面结构特征凹凸不平（类似哺乳动物T淋巴细胞）的为主。草鱼、中华鳖血液淋巴细胞和中华鳖胸腺细胞与抗人CD2单克隆抗体交叉反应的免疫组化检测显示中华鳖血液淋巴细胞和胸腺细胞的CD2阳性率分别为24％和33％。草鱼血液淋巴细胞CD2阳性反应不明显。