| This paper observed the gonad development of female Procambarus clarkii,optimized the conditions of light and salinity which can promote gonad development of female Procambarus clarkii, optimized the cryopreservation conditions of spawning crayfish, studied on the growth performance of crayfish breeding, provided a useful reference for scale breeding, seed breeding and breeding factory of Procambarus clarkii.Studying and observing the samples collecting from Xieqiao breeding base in Changshou City, Jiangsu Province, obtain the following results:1.Studying ovarian development of female Procambarus clarkii, dividing the ovarian development into six periods according to the color of ovary and size of eggs and morphological features of the female Procambarus clarkii, the results showed that:Suzhou, Jiangsu Province female Procambarus clarkii lay eggs once a year, mainly in the autumn and winter; influenced by the temperature in 2014, the growth period of female Procambarus clarkii ovary is longer, synchronicity is poor.2.Study on salinity and light induced gonad development of female Procambarus clarkii quickly. By set three salinity(0 ‰,(5 ± 2) ‰,(12 ± 2) ‰), and three kinds of light intensity(natural light(illumination> 800LX), stamped shade net(illuminance <800LX),no light) 9 groups test the impact of female Procambarus clarkii gonads, GSI and survival,the results showed that: salinity and light can effectively promote female Procambarus clarkii gonadal development, including light have greater impact. Salinity(5± 2) ‰, stamped shade net(light intensity <800 lx) can significantly promote female Procambarus clarkii gonadal development. Provide some guidance for female Procambarus clarkii artificial breeding of industrialization.3.Effects of low temperature on survival rate and hatching of fertilized eggs for brood’s original crayfish matrix. By setting a low temperature(0 ℃, 5 ℃, 10 ℃), the natural temperature(15 ℃, 20 ℃) and three types of habitateffect on the spawningProcambarus clarkii maternal survival and hatching of measuring survival berried female Procambarus clarkii shrimp, fertilized eggs and hatching incubation time.The results showed that: in female Procambarus clarkii breeding process at 5-10 ℃ temperature control can effectively control when female Procambarus clarkii fertilized embryos fertilized egg hatching rate and extend the incubation time, improve berried female Procambarus clarkii shrimp survival. To a certain extent, you can always call the time according to the sale of seedlings broodstock, Feeding time to ensure accurate, timely,Feeding time difference can be used to achieve higher economic returns.4. The offspring of the red swamp crayfish, Procambarus clarkii was divided into three groups based on body weight;large,medium and small for culture selection.For each group,we established three replicates to test their grown performance.Our results showed that after 40 days culture,the survival rate was larger than 50% in all three groups.Significant changes(P < 0.01) were detected for the body weight and length in the three groups,and the increase of body weight and length of the large-body group was significantly greater(P < 0.01)than the other two groups.After another 40 days culture,the variation among individuals of large-body group decreased.However,the competition among the three groups became more severe,with the survival rate lower than 50%.Such competition among individuals of the large-body group was stronger than the other two groups. Therefore, In artificial breeding should be selected on better growth performance of large-sized juveniles as a reserve breeding populations.Procambarus clarkii should arrange pre nurture nurturing juveniles density, appropriately increase the number of shelter, reducing the intensity of the struggle between juveniles and improve survival rate of breeding.Cultivation of late taken to catch big to stay small way listed in batches, fry guarantee supply, enhance economic efficiency. |
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