光照周期和光照强度对循环水系统中墨瑞鳕的生长、肌肉营养成分及养殖收益的影响

分别探究了4种光照周期(12L﹕12D、15L﹕9D、18L﹕6D和21L﹕3D)和4种光照强度(1200 lx、1500 lx、1800 lx和自然光)对循环水养殖系统中墨瑞鳕的生长、肌肉营养成分及养殖收益的影响。结果表明: (1)15L﹕9D组墨瑞鳕的终重、日增重及特定生长率均显著高于其他三组(P<0.05), 饵料系数显著低于12L﹕12D和21L﹕3D组(P<0.05); 1500 lx组墨瑞鳕的终重、日增重及特定生长率均显著高于其他三组(P<0.05), 饵料系数显著低于其他三组(P<0.05)。(2)15L﹕9D组墨瑞鳕肌肉中粗脂肪含量、氨基酸总量及必须氨基酸总量均达到最大值; 1500 lx组墨瑞鳕肌肉中粗脂肪和灰分含量最高, 而水分和粗蛋白含量最低; 相反, 自然光照组中水分和粗蛋白含量最高, 而粗脂肪和灰分含量最低(P<0.05)。(3)尽管15L﹕9D组和1500 lx组都投入了较高的成本, 但由于这两组中墨瑞鳕的生长快, 产量高, 其总收益、总净收益和效益成本比均显著高于其他实验组(P<0.05)。综合各项实验数据, 15L﹕9D和1500 lx分别为墨瑞鳕生长的最佳光照周期和最佳光照强度。研究为人工照明在循环水系统中的应用提供了参考依据。

EFFECTS OF PHOTOPERIOD AND LIGHT INTENSITY ON THE GROWTH,MUSCLE NUTRITION AND ECONOMIC PERFORMANCE OF MURRAY COD (MACCULLOCHELLA PEELII) IN THE RECIRCULATING AQUACULTURE SYSTEM

Light is an important environmental factor that affects fish growth, while there is limited research in recirculating aquaculture system. This study investigated the growth, muscle nutrition and economic performance of murray cod in the recirculating aquaculture system with different photoperiods (12L﹕12D, 15L﹕9D, 18L﹕6D, 21L﹕3D) and light intensities (1200 lx, 1500 lx, 1800 lx, natural light). The results showed that: (1) The final weight, daily weight gain and specific growth rate of 15L﹕9D group were significantly higher than those of other treatments (P<0.05), and the feed conversion ratio was significantly lower than the 12L﹕12D and 21L﹕3D groups (P<0.05). The final weight, daily weight gain and specific growth rate of 1500 lx group were significantly higher than those of other groups (P<0.05), and the feed conversion ratio was significantly lower than that of other groups (P<0.05). (2) The content of crude fat, total amino acids, and total essential amino acids of 15L﹕9D group were the highest. 1500 lx group had the highest content of crude fat and ash and the lowest content of moisture and crude protein. On the contrary, natural light group had the highest content of moisture and crude protein and the lowest content of crude fat and ash. (3) Although the 15L﹕9D and the 1500 lx group have invested relatively high costs, due to the fast growth and high output of the two groups, the total benefits, total net benefits, and benefit-cost ratios of the two groups significantly higher than other groups (P<0.05). In general, 15L﹕9D and 1500 lx are the best light condition for Murray cod in the RAS system, which provides a reference for the application of artificial lighting aquaculture.