Optimization Of Water Quality Control And Feeding Techniques For Litopenaeus Vannamei

Litopenaeus vannamei is the main kind of prawn cultured in China,and its output accounts for more than 85%of the total output of prawn.High-quality seed is the key to the success of shrimp culture.Besides the genetic germplasm of the parents,water quality and nutrition during the breeding process have a significant impact on the gonad development of the parent shrimp,which is also a key factor in determining the quality of the larvae.In this paper,the technological process of parent cultivation,seedling rearing and aquaculture production of Litopenaeus vannamei was summarized,and the water quality control and feeding technology were optimized through field experiments.The results show that:1.By optimizing the production and breeding of an air force in Jinzhou,Dalian,and optimizing the aquaculture water,feeding strategy and disease management,the risk of disease of shrimp seedlings was reduced and the resistance of larvae to diseases was enhanced;According to the different states of prawns,precise feeding amount,and timely adjustment.A total of 50,000 P7 shrimp seedlings(≈0.5cm,≈0.006g)were placed in 13m~3 water environment for high-density cultivation.After 25 days of standard seedling period,the final body weight reached 0.43g,body length reached 3.7cm,weight gain rate was 7066%,and survival rate was84%.19,500 seedlings were selected to be cultured in a breeding tank with an effective water body of 39 m~3.The size of the outlet tank reached 22-25 tail/500 g,the feed coefficient was 1.18,and the final breeding density was 7.5-7.69 kg/m~3.The breeding quality and yield were confirmed,and the breeding results were quite abundant.2.In the experiment,mature parent shrimp were bred after culture,and 1 to 14 breeding tanks were selected,each of which was a 90L white rectangular micro reservoir.The quantitative parent shrimp of Litopenaeus vannamei was selected to change the water,adjust the feeding amount,turn on the aerator and use microbial agents had certain effects on the aquaculture water body,and the water quality was improved in different degrees.3.Under the condition of satiation,the parent shrimps of Litopenaeus vannaeuswere cultured with live food for 30 days,and the effects of different feeding frequencies F2,F3 and F4(2,3 and 4 times/day)on feeding,growth,reproductive performance,offspring quality,body composition of shrimps and digestive enzyme activity of hepatopancreas were compared.The objective is to explore the optimal feeding frequency of nutritional fortification during reproductive period of parent shrimp.The results showed that with the increase of feeding frequency,the daily feed intake of parent shrimp gradually increased,and F2 group was significantly lower than F4 group(P<0.05),but there was no significant difference compared with F3 group(P>0.05);The weight gain rate and body length growth rate of parent shrimp increased first and then decreased,but there was no significant difference(P>0.05).Different feeding frequencies had no significant effects on single spawning quantity,relative spawning quantity,number of nodulus stage I individuals,hatching rate of nodulus stage I individuals,metamorphosis rate of nodulus stage I individuals,gonad index,time of first birth and interspawning period(P>0.05).In the best feeding environment,the feeding frequency of nutrient enhancement during the breeding period of Litopenaeus vannaeuswas 2 times/day.