RseB影响溶藻弧菌感染花鲈的能力

为了研究Rse基因缺失对溶藻弧菌感染花鲈能力的影响，评估了花鲈感染后的LD50、定殖能力和免疫响应，结果显示，溶藻弧菌野生株LD50为2.013×105CFU/ml，RseB缺失溶藻弧菌LD50为5.526×105CFU/ml，RseB缺失溶藻弧菌毒力下降2.75倍；溶藻弧菌主要在花鲈的鳃部、肠道、皮肤定殖，RseB缺失溶藻弧菌定殖肠空泡化程度更低，鳃组织结构的损坏程度更低；分别对野生株与RseB缺失溶藻弧菌感染的花鲈头肾组织进行转录组测序，发现与免疫相关的差异表达基因一共有236个，其中包括了122个显著上调的免疫基因和114个显著下调的免疫基因，这些基因大部分显著富集在Th1和Th2细胞分化、B细胞受体信号通路、T细胞受体信号通路等特异性免疫通路上，部分基因显著富集在与细胞凋亡相关的通路以及与炎症相关的NF-kappa B信号通路中。综上结果表明RseB缺失溶藻弧菌能引起宿主细胞的免疫反应且毒力有所降低。     

盐度与碱度对花鲈幼鱼的毒性研究

试验研究盐度与碱度对花鲈(Lateolabraxjaponicus)幼鱼的急性毒性结果表明,24h、48h、72h、96h碱度对花鲈幼鱼的半致死浓度(LC50)分别为101.05mmol/L、63.27mmol/L、56.85mmol/L和46.18mmol/L;盐度和碱度联合毒性试验结果显示碱度对花鲈幼鱼24h半致死浓度与盐度显著相关,二者间关系为ALK=125.05-2.18S(n=7,r=0.9756),表明盐度和碱度之间可能存在一定的交互作用。     

茄子叶片气孔密度与侧多食跗线螨发生数量的关系

 对27个茄子品种叶片气孔密度与侧多食跗线螨(Polyphagotarsonemus latus Banks)田间种群密度进行了相关性研究, 结果表明: 叶片背面气孔密度与该螨的田间种群密度呈显著正相关, 而叶片正面气孔密度则与之相关不显著。     

花鲈消化道粘液细胞的类型及分布

采用阿利新蓝与过碘酸雪夫氏染色方法(AB-PAS)(pH 2.6)和不同pH(1.0、2.5、3.1)的阿利新蓝染色法观察花鲈消化道(舌、食道、胃、肠)粘液细胞的类型与分布。根据AB-PAS染色结果将花鲈粘液细胞分成Ⅰ~Ⅳ4种类型:Ⅰ型为红色,AB阴性,PAS阳性,含中性粘多糖;Ⅱ型为蓝色,AB阳性,PAS阴性,含酸性粘多糖;Ⅲ型为紫红色,AB与PAS均为阳性,主要含有PAS阳性的中性粘多糖,同时含有少量AB阳性的酸性粘多糖;Ⅳ型为蓝紫色,AB与PAS均为阳性,主要含有AB阳性的酸性粘多糖,同时含有少量PAS阳性的中性粘多糖。不同pH的阿利新蓝染色结果为pH 2.5和pH 3.1溶液显示酸性粘液蓝色,pH 1.0溶液仅显示弱的和强的硫酸化酸性粘液蓝色。花鲈舌粘液细胞较少,以Ⅱ型为主;食道含有大量粘液细胞,以Ⅲ型和Ⅳ型为主;胃中只含大量Ⅰ型粘液细胞;肠中也有大量粘液细胞,以Ⅲ型和Ⅳ型为主。通过对各部位粘液细胞的分类和比较,可以看出粘液细胞的分布和类型与其所在部位执行的功能有密切的关系。     

鲈鱼在微冻保鲜过程中的质量变化

以感官评价、细菌总数、T-VBN、pH、ATPase活性、K等作为鲜度指标,研究鲈鱼在微冻(-3℃)保鲜过程中的质量变化规律,评价鲈鱼微冻保鲜的可行性.结果表明,鲈鱼在微冻过程中,①感官评分变化在前、中、后3个10天内下降速度分别为0.07、0.09、0.12分/天,但差异不显著;②细菌总数变化第30天下降至初始菌数的1/100;③T-VBN变化第30天时为0.156 6 mg/g,远未达到2级鲜度指标上限;④pH变化前10天一直下降,第10天最低为6.3,而后缓慢上升;⑤ATPase活性下降速度很快,第20天下降至0.005 3μmol/(min@mg),基本丧失活性;⑥K变化前5天由5.2%迅速升到22.33%,此后上升速度趋于缓慢,第30天达到34.362%.微冻可以明显抑制其细菌总数的增长,并维持其较低的T-VBN和K值.但是,微冻条件下鲈鱼的蛋白质变性速度较快.     

使用颗粒饵料养殖鲈鱼试验

本文报道了颗粒饵料养殖鲈鱼的效果。结果表明；使用颗粒产与使用鱼浆比较，鲈鱼增重率提高２．７０％，饵料系数降低２７．６％。     

花鲈鱼种日摄食节律的初步研究

花鲈鱼种的摄食具有明显的昼夜节律性，其摄食活动主要在白天进行，并以５：００￣６：００和１５：００￣１８：００最为活跃，表现出晨昏摄食的特点，花鲈的日摄食强度随日投饲次数的增加而增大，但增幅逐步减小，日摄食率与日投饲次数之间近似幂函数关系：Ｙ＝５．４４２０Ｘ＾０．１０９，饲料的能量转换效率随日投饲次数的增加而提高，日投喂四次时，接近最高值，若继续增加日投饲次数，能量转换效率不再明显提高。     

Effects of raw corn starch levels on growth, feed utilization, plasma chemical indices and enzyme activities in juvenile yellowfin seabream Sparus latus Houttuyn

A 10‐week growth trial was conducted to evaluate the effect of raw corn starch levels on the growth, feed utilization, plasma chemical indices and metabolic enzyme activities of juvenile yellowfin seabream Sparus latus. Four semi‐purified experimental diets with different raw corn starch levels (5%, 10%, 20% and 26%) and a high‐protein control diet were prepared before the experiment and hand‐fed to triplicate groups of juvenile yellowfin seabream Sparus latus. Weight gain and specific growth rate for fish fed the diet containing 26% raw corn starch were significantly lower than those for fish fed 10% or 20% corn starch diets or the high‐protein control diet. Fish fed 10% or 20% corn starch diets had a slightly better growth performance than those fed the 5% corn starch diet. Feed efficiency ratio and protein efficiency ratio (PER) for 20% raw corn starch fed fish were the highest among all groups, although no statistically significant differences were found among the experimental groups. The high‐protein control group had a significantly lower PER value than other groups. Protein productive values for fish fed the 5% raw corn starch diet and the high‐protein control diet were significantly lower than those of fish fed the 20% raw corn starch diet, but not significantly different from the values of any other group. The values of intraperitoneal fat ratio, viscerosomatic index and condition factor, as well as body and muscle compositions, were unaffected by corn starch levels. The hepatosomatic index and liver glycogen level for fish fed 5%, 10%, 20% raw corn starch and the high‐protein control diets were equal but significantly lower compared with that of fish fed the 26% raw corn starch diet. Plasma values of the fish were not affected by various dietary treatments, except that a significantly higher plasma glucose concentration was measured in the high‐protein control group compared with the values in the other groups. There were variations in the activities of hepatic hexokinase and pyruvate kinase of the yellowfin seabream after they had been fed different dietary raw corn starch levels for 10 weeks. The overall results showed that a 20% inclusion level of raw corn starch in the diet was better utilized by juvenile yellowfin seabream than 5%, 10% or 26% levels and had a protein‐sparing effect.     

Daily age and food habits of Lateolabrax latus larvae and juveniles occurring in the innermost shallow waters of Uwajima Bay, Japan

ABSTRACT:   Daily age and food habits of Lateolabrax latus larvae and juveniles were investigated at two different habitats in Uwajima Bay, western Shikoku, Japan. In the shallow zone at Miura, which contained eelgrass beds, larvae occurred from January and were collected abundantly in March. The size, age, and hatch-date distributions suggested that late-hatched specimens stay longer than early-hatched specimens at this station. On the contrary, in the intertidal flats of the Kunomura River mouth larvae were rarely collected, but juveniles were collected in relative abundance from April. The distributions in the intertidal flats station suggested that specimens had migrated from another location and then resided in the intertidal flats. Spatial and temporal trophic variations increased remarkably with metamorphosis, and thus, the spatial differences in growth rate were considered in relation to the trophic diversity of prey items. Our results suggest that the nursery environment, nursery utilization pattern, and food habits of early life stages of L. latus show remarkable flexibility. From the similarity of these ecological aspects with L. japonicus , which is a closely related species, we suggest the important role of the interspecific competition to the realized niche difference between Lateolabrax congeners.     

茶跗线螨空间分布型及理论抽样技术研究

在田间调查的基础上,运用聚集度指标法、Iwao回归分析法及Talor幂指数法对茶跗线螨在茶园中的空间分布型、理论抽样数技术进行研究,同时根据1wao的理论抽样数模型确定了茶跗线螨的最适理论抽样数。结果表明：茶跗线螨在茶园中的空间分布为聚集分布,基本成分为个体群,个体间相互吸引,个体群在茶园中呈聚集分布。同时其聚集程度随种群密度的增加而增强。根据各项聚集度指标得出茶跗线螨田间调查的理论抽样数公式为：N=t2/D2（12.557/m＋0.340）.本研究结果为茶园茶跗线螨预测预报及防治提供了科学依据。