循环水养殖系统在凡纳滨对虾种虾养殖中的应用效果初探

Preliminary Application of the Recirculating Aquaculture System in Litopenaeus vannamei Breeding

循环水养殖系统在凡纳滨对虾种虾养殖中应用较少,本研究应用循环水养殖系统养殖凡纳滨对虾种虾,设定4个不同的养殖密度(30、40、50、65尾/m2),初始体重:(0.102±0.008)g,研究凡纳滨对虾种虾在循环水养殖系统中的生长情况。养殖期间定时对对虾体重和水体指标(氨氮、亚硝酸氮、pH、水温、微生物)进行分析测定。通过对各项数据分析表明:低密度组(30、40、50尾/m2)凡纳滨对虾体重增长较快,各组特定生长率分别为(3.83±0.03)%、(3.87±0.01)%、(3.81±0.03)%,绝对增重率分别为(0.201±0.009)、(0.214±0.004)、(0.194±0.009)g/d,但均无显著性差异(P>0.05);高密度组(65尾/m2)的凡纳滨对虾体重增长较慢,特定生长率和绝对增重率分别为(3.41±0.02)%和(0.107±0.004)g/d,该结果与低密度组间存在显著性差异(P<0.05)。低密度组中凡纳滨对虾养殖水体的水质指标要优于高密度组,4个密度组中氨氮、亚硝酸氮、绿菌均维持在安全浓度范围内,仅仅黄菌数量略高。综合分析,采用该养殖系统养殖凡纳滨对虾的最优密度为50尾/m2。因此,本研究可为循环水养殖系统养殖凡纳滨对虾种虾提供参考。

Litopenaeus vannamei（Pacific white shrimp,also known as Penaeusvannamei）is one of the most important farmed shrimp species in the world.L.vannamei was introduced into China in 1988 and now,after 27 years of practical experience,it has become a dominant variety in China.Stocking density is a key factor in shrimp breeding.It affects survival and growth of L.vannamei during the culture.Driven by the market demand,semi-intensive,intensive,and high-density shrimp farming have expanded steadily over the last two decades in China.In addition,there is growing interest in using recirculating aquaculture systems（RAS）to breed aquatic livestock in many places.The recirculating aquaculture system（RAS）is a research system for use in aquaculture.It has been little used in Litopenaeus vannamei breeding until now.Therefore,an indoor and closed RAS for L.vannamei was constructed in this study.We investigated the water quality,growth performance of L.vannamei,and bacterial communities in the closed recirculating system.Growth and water quality（concentrations of total ammonia nitrogen and nitrite nitrogen,pH,temperature,and biomass of microorganisms）were investigated in this system at four different stocking densities（30,40,50,and 65shrimps·m^-2）.It is shown that both the special growth rate and absolute growth rate were different in the four densities.Ponds stocked with 30,40,and 50shrimps·m^-2showed the best weight gains.Weight gain,special growth rate,and absolute growth rate were significantly correlated with stocking density（P〈0.05）.The special growth rates were（3.83±0.03）%,（3.87±0.01）%,（3.81±0.03）%,and（3.41±0.02）% with 30,40,50,and 65shrimps·m^-2,respectively.The absolute growth rates were（0.201±0.009）,（0.214±0.004）,（0.194±0.009）,and（0.107±0.004）g/d with 30,40,50,and 65shrimps·m^-2,respectively.The specific growth rates and the absolute growth rates of 65shrimps·m^-2 in the current study were significantly lower than in another groups（P〈0.05）.The quality criteria of the recirculate water for the three lowest densities（30,40,and 50shrimps·m^-2）were controlled within suitable ranges compared with those for the highest density（65shrimps·m^-2）during a culture period of 162 days.In this study,ammonia nitrogen,nitrite nitrogen,and＂green＂vibrion concentrations were adapted to the L.vannamei growth,but the＂yellow＂vibrion concentration was higher than the upper normal limit.Therefore,the optimal shrimp density in the RAS during the experimental culture was 50shrimp· m^-2.Our findings clearly showed that the shrimps of 50shrimp·m^-2in a closed recirculating system had low inorganic nitrogen levels,particularly ammonia nitrate,and resulted in better water and shrimps quality.In the long run,the current study aims to evaluate growth performance of L.vannamei in novel RAS and traditional ponds in order to determine the general suitability of RAS for culture of the L.vannamei.