饲料中添加钾和镁对淡水养殖凡纳滨对虾生长性能和成活率的影响

Effects of Potassium and Magnesium Supplement in Feed on Growth Performance and Mortality of Litopenaeus vannamei Cultured in Fresh Water

试验研究了钾和镁的添加剂(缓释型硫酸钾镁)对淡水养殖凡纳滨对虾的影响。选用90 000尾健康凡纳滨对虾[体重(0.001 7±0.000 1) g、体长(1.267±0.008) cm]随机分为5组,对照组投喂普通对虾饲料,处理组在普通对虾饲料中分别添加2、4 kg/t和6 kg/t的缓释型硫酸钾镁,在普通对虾饲料中添加2 kg/t硫酸镁·氯化钙混合物为正对照组,每个处理6个重复,池子规格为2 m×3 m×1.5 m,每池放养3 000尾凡纳滨对虾苗。试验开始、第35天、第70天每池捞取50尾虾,测定体重和体长。试验结束时,计算回捕虾数量。试验结束时,每池随机取5尾虾,剥离获得第一胸节肌肉,测定对虾肌肉的质构特性。结果表明,添加缓释型硫酸钾镁显著地改善凡纳滨对虾的增重、增重率,降低了饵料系数,提高成活率,改善肌肉的质构特性。缓释型硫酸钾镁与硫酸镁·氯化钙混合物对凡纳滨对虾的生长和成活率的影响比较接近。在本试验条件下,在饲料中添加4 kg/t缓释型硫酸钾镁对淡水养殖凡纳滨对虾的生长性能、成活率和肌肉质构特性是有益的。

The effect of supplement(Dipotassium dimagnesium trisulfate)of potassium and magnesium was studied in Litopenaeus vannamei cultured in fresh water.90000 healthy shrimp[BW(0.0017±0.0001)g,BL(1.267±0.008)cm]were used and allotted randomly to 5 treatments with 6 replicas.Control group was fed with common shrimp feed.The other four groups were fed with common shrimp feed supplemented with 2 kg/t,4 kg/t,6 kg/t dipotassium dimagnesium trisulfate and 2 kg/t calcium chloride and magnesium sulfate mixture respectively.The culture pool size was 2 m long,3 m wide and 1.5 m deep.In the beginning 3000 shrimp larvae were put into each pool.50 shrimp were selected randomly from each pool to determine the body weight and body length in the beginning,35th day and 70th day respectively.All shrimp were caught to calculate the mortality.At the end of experiment,5 shrimp were selected randomly in each pool to determine the muscle texture.The results showed that supplement of dipotassium dimagnesium trisulfate improved the weight gain,weight gain rate,feed conversion ratio,survivability and muscle texture feature compared to control group.Dipotassium dimagnesium trisulfate had the similar effect on the growth performance and mortality of shrimp compared to calcium chloride and magnesium sulfate mixture supplement.So 4 kg/t supplement of dipotassium dimagnesium trisulfate was recommended in Litopenaeus van⁃namei feed in fresh water.