罗非鱼Oreochromisspp.是我国重要的水产养殖品种。我国是世界最大的罗非鱼生产国和出口国。但罗非鱼性成熟早、繁殖过度,致使商品鱼品质偏低、资源浪费严重,解决途径为采用单雄性养殖。本文进行了温度调控诱导尼罗罗非鱼仔鱼雄性化的研究。较之前常采用的雄激素投喂方式更环保、安全、高效。控温处理开始时期为出膜后第7天(DPH,DaysPostHactching),进行正交试验:设置3个温度20、28、36oC(±0.5℃),3个控温时段7—14DPH、7—21DPH、7—28DPH。主要结果如下:处理组合(温度+控温时段)为36℃+7—14DPH、36℃+7—21DPH、36oC+7—28DPH时雄性率较对照组显著增高、与其它各组有显著差异(P〈0.05),分别高达93.85%、96.00%和96.92%,这3组问无显著差异(P〉0.05)。为了解控温对仔鱼的影响,还同步研究了相应的增质量率和存活率。由控温时段结束至60DPH的绝对增质量率来看:处理组合36℃+7—14DPH、28℃+7—14DPH与对照组无显著差异(P〉0.05);从存活率来看:只有处理组合20qc+7—21DPH、20℃+7—28DPH与对照组有显著差异(P〈0.05)。综合来看,最佳处理组合为36℃+7—14DPH,平均雄性率93.85%、最高达96.96%,且高温(36℃)处理后生长和存活不受影响。
The tilapia (Oreochromis spp. ) is very important for fishery in China. China is the first in the amount of product and export of tilapia in the world every year. The period of tilapia' s maturation is very short. So the reproduction is very fast and waste a lot of energy. The style of mono-male cultivation can resolve the problems. In this paper, the researches have been concentrated on the male rates under different water temperature condition in larva Nile Tilapia (Oreochromis niloticus L. ). The possibility of making mono-male by temperature controlling has been discussed from two aspects: the effective tempera- ture and the disposal duration time. The larvae were treated from 7DPH. Two factors were considered: the water temperature (20 ℃, 28 ℃, 36 ℃) and the disposal duration time (7 - 14DPH, 7 - 21DPH, 7 -28DPH). They were taken into account by orthogonal experimental design. The main results are as follows : at the aspect of getting mono-male by temperature control, when the temperature is 36 ℃,the male rates in the three disposal duration (7 -14DPH; 7 -21DPH; 7 -28DPH) are significant higher than the other treatment schemes ( P 〈 0. 05 ) , the male rates are 93.85%, 96. 00% and 96.92% respectively. In order to evaluate the effects of masculinization, the growth rates and the survival rates have been studied too. When the treatment schemes (temperature + disposal duration time) are 36 ~C + 7 -14DPH, the AGR and survival rate are no significant difference with the Control Group (P 〉 0.05 ). In general, the best treatment schemes are 36 ℃+7 - 14DPH, the average male rate is 93.85% and the highest male ratio is 96. 96%. The growth rate and the survival rate in that treatment schemes are normal too.