串联养殖模式下的凡纳滨对虾(Litopenaeus vannamei)与缢蛏(Sinonovacula constricta)生长特性、消化免疫及水生态效应

GROWTH PERFORMANCE AND AQUATIC ECOLOGICAL EFFECT IN TANDEM CULTURE OF SHRIMP LITOPENAEUS VANNAMEI AND RAZOR CLAM SINONOVACULA CONSTRICTA

虾蛏串养模式作为海水围塘养殖坚持可持续发展、绿色发展的模式,已在福建沿海地区推广,取得明显效果,但目前适宜于该模式下的虾蛏数量配比尚不清楚。在实验室内,通过设立LP组(虾蛏数量配比1︰3)、MP组(1︰5)、HP组(1︰7),模拟虾蛏串联养殖模式,对虾和缢蛏分别投喂颗粒饲料、微绿球藻和角毛藻,并对虾蛏生长特性、养殖环境水质因子、消化与免疫指标、环境与蛏内脏团微生物群落进行探究。结果表明,LP组和MP组虾蛏增重率和特定生长率显著高于HP组。LP组和MP组对虾增重率分别为43.88%、41.91%,缢蛏增重率分别为29.30%、29.40%。水质营养盐浓度开始总体升高达到峰值后总体下降。虾蛏对环境反应不同,缢蛏中淀粉酶和过氧化氢酶活性变化显著,对虾则是胰蛋白酶和超氧化物歧化酶活性变化显著。RDA分析表明,总氮、活性磷酸盐是影响微生物群落关键因素。16S rRNA分析表明,虾蛏不同数量配比对养殖环境以及缢蛏内脏团有较大影响,与LP组相比,MP组和HP组微生物种类更多,且参与氮磷循环的微生物丰度增加。当虾蛏数量配比为1︰3或者1︰5时,虾蛏能良好生长且串养系统养殖环境能起到改善作用。研究结果有助于优化虾蛏串养模式,对今后虾蛏串养模式健康发展具有重要意义。

The tandem culture of shrimp Litopenaeus vannamei(L)and razor clams Sinonovacula constricta(S)in seawater pond is a sustainable practice and a green development model,which is being promoted widely in coastal areas of Fujian,South China with a good achievement.However,the appropriate proportion of each species involved remains unclear.We tested the L-S tandem culture in different L︰S proportions(low 1︰3,LP;middle 1︰5,MP;and high 1︰7,HP),in which L and S were fed pelleted diets of Nannochloropsis oculata and Chaetoceros,respectively,and the growth performance was monitored and analyzed in terms of water quality factors,digestive and immune indicators,and microbial communities in the ambiance and razor clam viscera.The results showed that the weight gain rate and specific growth rate of L and S were significantly higher in the LP group than in the HP group,with the MP group being similar to the LP group.The weight gain rates were 43.88%and 41.91%for shrimp and 29.30%and 29.40%for razor clams in the LP and MP groups,respectively.The water nutrient concentration increased before reaching peak value and then decreased overall.The shrimp and clams responded differently to the environment.The activities of amylase and catalase in the clams changed significantly,while the activities of trypsin and superoxide dismutase changed significantly in shrimp.The redundancy analysis showed that total nitrogen and reactive phosphate were the key factors affecting the microbial community.As 16S rRNA analysis shown,different L︰S proportions had a greater impact on the culture environment and the visceral mass of the clam.The microbial species were more diversified and the microorganism that involved in nitrogen and phosphorus cycling were more abundant in the MP and HP groups than those of the LP group.Therefore,the L︰S proportions of 1︰3 or 1︰5 shall be a good choice in the L-S tandem culture.This study provided a good reference for similar aquacutural practices in a healthy and sustainable way in the future.