长江中游草鱼仔鱼的日龄和生长研究

采用耳石日轮鉴定了19988年采自长江九江江段和1999年分别采自长江石码头和纱帽江段的草鱼仔鱼的日龄,并依据日龄推算了仔鱼的孵化期和估计了日生长率.采自九江、石码头和纱帽江段的仔鱼的平均日龄分别为10.7d,8.8～16.0d和7.0d.石码头江段仔鱼中,5月16日样本的日龄稍高(16.0d),其余样本的日龄比较接近(8.8～9.5d).采自石码头江段的所有仔鱼的体长平均生长率为0.11mm·d-1,特定生长率为 1.32%.各批次仔鱼的体长与其日龄的相关性通常很差,这表明长江中游仔鱼的生长不整齐,部分个体可能遭受了营养缺乏的影响.     

Role of free neuromasts in larval feeding of willow shiner Gnathopogon elongatus caerulescens Teleostei, Cyprinidae

ABSTRACT:   It has been reported that the larvae of willow shiner Gnathopogon elongatus caerulescens have many free neuromasts on their body surface. This study examined the ability of the willow shiner larvae to feed on zooplankton by mechanoreception by the free neuromasts. Feeding experiments using untreated larvae and larvae treated with streptomycin, which impairs free neuromast function, were conducted under light and completely dark conditions. The larvae were put into Petri dishes, then nauplii of Artemia salina were introduced. The average number of Artemia eaten by the larvae was expressed as the average ingestion rate of Artemia /10 min. The ingestion rate of Artemia for untreated larvae was 12.3 under light conditions and 10.6 Artemia /10 min. even in complete darkness. The ingestion rate in the larvae treated with streptomycin was 11 under light conditions and only 0.8 Artemia /10 min under dark conditions. The low rate in the treated larvae under dark conditions must be due to impairment by the streptomycin. Therefore, the high ingestion rate for the untreated larvae under dark conditions would be surely dependent on mechanoreception. The results indicate that larval willow shiner is able to feed on zooplankton under limited light conditions.     

不同温度对红鳍东方(鱼屯)仔、稚、幼鱼形态发育和生长的影响

通过对三个不同水温的红鳍东方纯育苗池的仔、稚、幼鱼的连续取样观察,分析比较在不同的培育水温对红鳍东方(鱼屯)的形态发育和生长的影响。通过试验分析表明,在红鳍东方纯适宜的温度范围内的增温对红鳍东方(鱼屯)稚、幼鱼的影响效果明显,且不会降低成活率,从而可缩短育苗时间,降低成本,减少风险。     

不同药剂对铜绿丽金龟卵和幼虫室内药效及毒力测定

11种杀虫剂对铜绿丽金龟卵和幼虫室内药效及毒力测定结果表明,25%吡虫·辛硫磷乳油、20%氯虫苯甲酰胺悬浮剂、10%吡虫啉可湿性粉剂对铜绿丽金龟卵具有相对较好的防治效果;40%甲基异柳磷乳油、40%辛硫磷乳油、40%氧化乐果乳油、90%敌百虫原药、40%毒死蜱乳油、25%吡虫·辛硫磷乳油、10%噻虫嗪可湿性粉剂、10%吡虫啉可湿性粉剂对铜绿丽金龟二龄幼虫均具有较高的持久防效;吡虫啉与辛硫磷复配防治铜绿丽金卵和二龄幼虫有显著的增效作用。     

黑莓鲈（Pomoxis nigromacufatus）仔鱼饥饿试验及 PNR 的确定

为确定黑莓鲈仔鱼的饥饿耐受能力及死亡不可逆点（PNR）,采用实验生态学方法研究饥饿对黑莓鲈仔鱼摄食、生长与发育的影响。结果表明,在19．5～22．8℃水温条件下：①黑莓鲈仔鱼在6日龄开口摄食,8日龄卵黄囊消失,其混合营养期仅维持2 d 左右,属于易遭受饥饿胁迫鱼类;②仔鱼最高初次摄食率出现在9日龄,初次摄食期仔鱼的 PNR 发生在孵化后第11～12 d,仔鱼具有摄食能力的时间仅4～5 d,且在到达 PNR 后仅1 d 多即全部死亡,其耐受饥饿的能力较差;③在饥饿胁迫条件下的仔鱼对卵黄囊和油球的吸收进程明显慢于正常投喂组仔鱼,且随着饥饿程度的不断加深,仔鱼的生长发育趋于停滞甚至出现负增长;仔鱼在 PNR 期出现胸角,并且表现出一系列明显的由饥饿所导致的形态和行为学特征。     

大麦虫幼虫营养成分分析

以大麦虫幼虫为研究对象,采用国家标准测定分析大麦虫幼虫水分、粗脂肪、粗蛋白、灰、部分维生素、矿物质元素及氨基酸组成。结果表明：（1）大麦虫活虫含水分57.87%、粗脂肪20.13%、粗蛋白18.69%、灰分1.72%;以干物质计,含粗脂肪38.99%、粗蛋白49.51%、灰分2.13%;（2）幼虫粉脂溶性维生素中,VE的含量最高,为23.49（依0.06）mg/kg;水溶性维生素中,VC 的含量最高,为16.04（依0.03）mg/kg,其次是VB2 ,为13.60（依0.09）mg/kg;（3）幼虫粉的宏量元素中,钾（K）的含量最高,为7 620.12（依2.26）mg/kg;其次是磷（P）、为6 150.48（依6.53）mg/kg;钙（Ca）的含量最低,为1 005.02（依4.08）mg/kg;微量元素中,锌（Zn）的含量最高,为88.74（依1.60）mg/kg;其次是铁（Fe）,为78.30（依1.78）mg/kg;铜（Cu）和锰（Mn）的含量分别为14.71（依0.21）mg/kg 和18.73（依1.09）mg/kg;（4）幼虫粉中氨基酸组成有17 种,氨基酸总量达41.92 g（每100 g幼虫粉）,其中必需氨基酸占氨基酸总量的44.80%,呈味氨基酸占36.64%。     

Improved performance of gilthead sea bream, Sparus aurata, larvae after ozone disinfection of the eggs

Ozone (O₃) dissolved in seawater (ODS) was evaluated, as an egg disinfectant, on the spawn of captive gilthead sea bream, Sparus aurata, brood stock. Four contact times (CT) were tested (0.6, 1.2, 2.4 and 4.8 mg min L⁻¹) where CT was calculated by multiplying the dissolved O₃ concentration (0.3 mg L⁻¹) by different exposure periods (2, 4, 8, 16 min). There was also a disinfected seawater treatment that contained no O₃ or derived compounds (CT 0) and an untreated seawater control. All ODS treatments reduced egg surface bacterial counts to zero, which was significantly (P<0.05) lower than the CT 0 and the control groups (194 and 1320 plate⁻¹ respectively). Nevertheless, the hatching rate was high in the control and the CT treatments 0, 0.6 and 1.2 (88.7%, 87.3%, 89.5% and 83.7% respectively) while eggs exposed to a CT 2.4 and 4.8 hatched poorly (36.5% and 20.4% respectively), which was likely due, at least in part, to larvae unable to break the egg chorion successfully. Swim‐bladder inflation was significantly higher in the ODS groups (>97%) compared with the control and CT 0 treatments (ca. 70%). The results suggest that a 2‐min exposure of eggs to 0.3 mg O₃ L⁻¹ of ODS (CT 0.6) would improve current protocols in marine larviculture.     

Maturation of the pancreatic and intestinal digestive functions in sea bass (Dicentrarchus labrax): effect of weaning with different protein sources

The maturation of the digestive functions in sea bass (Dicentrarchus labrax) larvae was evaluated by the enzymatic profile of pancreas and intestine brush border membranes. Sea bass larvae were weaned at day 25 with three simplified diets different by their protein nature: 100% fish meal (FP), 100% casein mixture (CP) and 50% fish meal-50% casein mixture (CFP). The casein mixture contained 35% of hydrolysate. The control group was fed live preys. The specific activity of amylase decreased with age irrespectively of the diets whereas the specific activity of trypsin was enhanced. The casein mixture reduced pancreatic secretion in amylase and trypsin. The CFP group differed from the other groups fed on compound diets, exhibiting as soon as day 32 high activities of brush border enzymes, similar to controls. This sharp increase between day 25 and 32 appeared to be crucial for larval survival. The addition of a protein hydrolysate in a weaning diet seems to facilitate this maturation process.     

中国对虾幼体的能量代谢

近年来中国对虾(Penaeus orientalis)工厂化育苗技术的进步,已能使海捕亲虾与养殖越冬亲虾在人工控制的条件下产卵,然而虾卵孵化之后能否健壮地生长以及如何提高变态存活率,幼体的饵料起着关键的作用。生物饵料虽然效果好,但受到培养技术及设备等条件的限制,因此,目前育苗生产中的饵料仍以豆浆、蛋黄为主,辅以少量的生物饲料与配合饵料,以致幼体的抗病力差,变态存活率低。所以研究适合于中国对虾幼体营养需求的配合饵料很重要。至今有关日本对虾幼体营养的研究屡见报导,而中国对虾幼体的营养研究还未有报导。对虾营养的研究方法有分析虾体成分、梯度或正交法设计饲料试验以及能量代谢试验等。周洪琪(1990)通过能量代谢研究中国对虾亲虾的营养。Harris(1959)、Conover