The evaluation of secondary stress response of grass carp (Ctenopharyngodon idella, Val. 1844) after exposing to the saline water

The stress response of grass carp to salinity was evaluated assessing the levels of hematocrit, leucocrit, plasma glucose, sodium, potassium and calcium. Mean hematocrit values increased following exposure to salinity. Mean leucocrit values elevated after exposure to salinity for 24 h, then decreased. Mean plasma glucose increased during saline exposure for 48 h and then decreased to normal values. Plasma sodium and chloride levels were increased to their highest values after 48 h. While plasma potassium value increased with the exposure time, plasma calcium values were not affected by salinity exposure.     

Induction of larval settlement and metamorphosis of the abalone, Haliotis discus hannai larvae using bromomethane and potassium chloride

Larvae of Haliotis discus hannai were induced to settle and metamorphose by exposure to seawater supplemented with bromomethane. The settlement and metamorphosis of veliger larvae were observed with bromomethane concentrations of 300, 600, 900, 1200, 1500 ppm on the benthic diatom plates. The highest settlement and metamorphosis rates of larvae were observed in bromomethane concentrations of 600 ppm.

Abalone larvae were induced to settle and metamorphose by exposure to seawater supplemented with potassium chloride. The settlement and metamorphosis of veliger larvae was observed in potassium chloride concentrations of 14, 19, 24 and 29 mM on the benthic diatom plates. The highest settlement and metamorphosis rates of larvae were observed in potassium chloride concentrations of 14–19 mM.     

Improved survival of rohu, Labeo rohita (Hamilton-Buchanan) and silver carp, Hypophthalmichthys molitrix (Valenciennes) fingerlings using low-dose quinaldine and benzocaine during transport

The effects of fingerlings immersion in low‐dose benzocaine (15 and 30 mg L⁻¹, silver carp and rohu) and quinaldine (100 μL L⁻¹ silver crap and 250 μL L⁻¹ rohu) for 1, 3 and 6 h on stress responses and survival of rohu, Labeo rohita and silver carp, Hypophthalmichthys molitrix fingerlings were evaluated in a transport simulation experiment. Both quinaldine and benzocaine showed low mortalities (0–2%). The total mortality in control (with no anaesthesia) was 30% for rohu and 14% for silver carp. Quinaldine and benzocaine‐treated fingerlings had significantly higher plasma chloride levels than the control in both species. Benzocaine, quinaldine, as well as the control, had an initial elevation of plasma cortisol levels. Benzocaine lost its effectiveness after 3 h exposure while quinaldine persisted throughout the 6 h experimental period. Both sedatives reduced bacterial build‐up compared with the control. No post‐exposure mortality was observed for any of the transport methods assessed 48 h after the treatment. This study suggests that the use of low‐dose benzocaine or quinaldine during transport has positive effect on the survival and health of rohu and silver carp fingerlings.     

壳寡糖及其复合聚合氯化铝絮凝微藻富集的研究

［目的］ 为了找到可以加速微藻富集的合适絮凝剂。［方法］ 制备了壳聚糖的降解产物壳寡糖,用于绿色巴夫藻（Pavlovaviridis Tseng, Chen et Zhang）和小球藻（Chloreiia spp.） 絮凝富集。［结果］ 终浓度为30 mg/L以上的壳寡糖溶液对2种藻类具有显著的促沉降效应。当壳寡糖与6 mg/L聚合氯化铝混合使用时,壳寡糖/聚合氯化铝促沉降效应明显提高。［结论］ 壳寡糖可以用于微藻大规模生产的采收。     

烯唑醇·苯醚甲环唑和咪鲜胺锰盐对饰纹姬蛙蝌蚪的急性和联合毒性

[目的]了解3种杀菌剂对水生生物的急性和联合毒性.[方法]采用静态换水方法研究了烯唑醇、苯醚甲环唑、咪鲜胺锰盐3种杀菌剂对饰纹姬蛙蝌蚪的急性毒性及其联合毒性,并对其进行了安全性评价.[结果]在急性毒性试验中,烯唑醇在24、48和72 h的半致死浓度（LC50）分别为60.80、62.40和41.20 mg/L;苯醚甲环唑的LC50分别为11.50、10.40和9.00 mg/L;咪鲜胺锰盐的LC50分别为49.30、6.40和3.00 mg/L;烯唑醇、苯醚甲环唑、咪鲜胺锰盐对饰纹姬蛙蝌蚪的安全浓度（SC）分别为19.90、2.50和0.03 mg/L.在联合毒性试验中,烯唑醇＋苯醚甲环唑的联合毒性和咪鲜胺锰盐＋苯醚甲环唑联合毒性均表现为协同作用,咪鲜胺锰盐＋烯唑醇联合组中除了0.6U ＋0.4U毒性比组均表现为协同作用外,其他3个毒性比组均表现为拮抗作用.[结论]为进一步了解农药对两栖类的毒性影响以及农药在农业中的合理使用提供了参考.     

Physiology of seawater acclimation in the striped bass,Morone saxatilis (Walbaum)

Several experiments were performed to investigate the physiology of seawater acclimation in the striped bass, Morone saxatilis. Transfer of fish from fresh water (FW) to seawater (SW; 31–32 ppt) induced only a minimal disturbance of osmotic homeostasis. Ambient salinity did not affect plasma thyroxine, but plasma cortisol remained elevated for 24h after SW transfer. Gill and opercular membrane chloride cell density and Na⁺,K⁺-ATPase activity were relatively high and unaffected by salinity. Average chloride cell size, however, was slightly increased (16%) in SW-acclimated fish. Gill succinate dehydrogenase activity was higher in SW-acclimated fish than in FW fish. Kidney Na⁺, K⁺-ATPase activity was slightly lower (16%) in SW fish than in FW fish. Posterior intestinal Na⁺,K⁺-ATPase activity and water transport capacity (J_v) did not change upon SW transfer, whereas middle intestinal Na⁺,K⁺-ATPase activity increased 35% after transfer and was correlated with an increase in J_v (110%). As salinity induced only minor changes in the osmoregulatory organs examined, it is proposed that the intrinsic euryhalinity of the striped bass may be related to a high degree of “preparedness” for hypoosmoregulation that is uncommon among teleosts studied to data.     

盐碱地池塘4种养殖模式的鱼产量及负荷力

在氯化物型盐碱地池塘中 ,采用围隔实验生态学方法对鲤、草鱼、罗非鱼和淡水白鲳等 4种鱼类混养模式的鱼产量、负荷力和搭配比例进行对比研究。结果表明 ,4种养殖模式中吃食性鱼类的日增重率和收获规格都随其本身放养密度的增大而减小 ,而鲢、鳙的日增重率和收获规格则随吃食性鱼类放养密度的增大而增大 ;吃食性鱼类的日增重率以淡水白鲳最快 ,草鱼生长最慢 ;吃食性鱼类的净产量为鲤模式 (CC) >罗非鱼模式 (TH) >淡水白鲳模式 (FP) >草鱼模式 (GC) ,混养的鲢在各种模式中的产量顺序为CC >GC >TH >FP ,鳙为CC >GC >FP >TH。CC、GC、TH、FP模式的总净产量分别为 4 .0 2～ 6 .5 5、3.0 5～ 5 .2 6、3.4 5～ 5 .86、2 .99～ 5 .34g/ (m2 ·d) ;FP、CC、TH、GC模式的负荷力分别为 0 .6 0 4、0 .4 92、0 .4 37和 0 .4 30kg/m2 。     

Immunohistochemical study on changes in gill Na+/K+-ATPase α-subunit during smoltification in the wild masu salmon, Oncorhynchus masou

Changes in immunoreactivity of Na⁺/K⁺-ATPase -subunit in gill sections of wild masu salmon (Oncorhynchus masou) during the parr-smolt transformation (smoltification) were compared with changes in gill Na⁺/K⁺-ATPase specific activity. Gill Na⁺/K⁺-ATPase specific activity increased from April and peaked in May. Immunohistochemical analysis, using an antiserum against a synthetic oligopeptide based on the conserved region of the Na⁺/K⁺-ATPase -subunit, revealed that immunoreactivity was confined to chloride cells in the surface layer of primary lamellae and the proximal end of secondary lamellae. The size and number of these cells increased gradually from February to May; however, the number of chloride cells of the secondary lamellae decreased in May. These data suggest that the synthesis of Na⁺/K⁺-ATPase and the proliferation of chloride cells occur prior to the elevation of enzyme activity. Moreover, it is likely the proliferation and hypertrophy of chloride cells on primary lamellae prepare smolts for entry into seawater and migration in the ocean.     

Response of pea (Pisum sativum L.) to mepiquat chloride under varying application doses and stages

Grown as a monoculture, peas (Pisum sativum L.) exhibit severe lodging after flowering and lodging causes yield reductions considerable. This study was conducted to investigate the effects of dose (untreated, 25, 50, 75 and 100 g a.i. ha^?1) and stage (late vegetative, early blooming and early pod filling) of mepiquat chloride (MC) application on the growth, lodging control, seed yield and yield parameters of pea (Pisum sativum L.) under field conditions in Erzurum, Turkey in 2002 and 2003. Application doses of 25, 50, 75 and 100 g a.i. ha^?1 significantly reduced stem height by 5.3 %, 7.2 %, 7.5 % and 6.4 % and increased stem width by 7.5 %, 12.7 %, 12.3 % and 15.7 % respectively, when compared with the untreated control, and thereby reduced the tendency of the crop to lodging. Increases of the seed yield under different application doses of MC ranged between 13.7 % and 20.1 % over the untreated control. However, in all parameters investigated, except for stem width, higher application doses of MC gave no clear advantages compared with the application dose of 25 g a.i. ha^?1. Seed yield was also significantly influenced by application stage of MC and application at early blooming stage of crop, MC significantly increased seed yield by 11.4 % and 10.2 % when compared with the late vegetative and the early pod filling stages respectively. Furthermore, the interaction of application dose and stage was significant, and spraying of pea plants with 25 g a.i. ha^?1 MC at early blooming stage has the most beneficial effects on the characters evaluated.     

氯化钾缓解肉仔鸡热应激的研究

120只28日龄艾维茵(AVIAN)肉仔鸡随机分为1、2、3、4组.1组为对照组,饮自来水;2、3、4组为试验组,分别饮添加0.18％、0.26％、0.34％氯化钾的自来水.舍温控制在34±1℃.试验期为4周.结果,各组鸡增重、采食量、饲料效率、饮水量的顺序均为第4组→第3组→第2组→第1组.饮水中添加KCI,肉仔鸡血清K~ 浓度高于对照组,而直肠温度、呼吸率及血清尿酸浓度则相反.血清Na~ 前两周3、4组显著低于1组,以后趋于一致.血细胞压积(PCV)、血液PH、CO_2分压(PCO_2)、氧分压(PO_2)、碳酸氢根(HCO_3)和血清中总蛋白、白蛋白、白/球比以及血糖,组间均差异不显著.本试验表明,饮水中添加KCI能较好地缓解热应激对肉仔鸡生长的影响,增强肉仔鸡对高温的耐受性,并可提高其生产性能.