點帶石斑魚和龍膽石斑魚之氮排放速率研究

Abstract

台灣石斑魚養殖以點帶石斑魚和龍膽石斑魚最為常見，其具有高單價、換肉率高，生長快速，而鮮美的肉質受到許多人的喜愛，但是點帶石斑魚和龍膽石斑魚在不同體型下的氮排放速率相關研究鮮少，故本篇論文研究點帶石斑魚和龍膽石斑魚的氮排放速率，了解不同體重的石斑魚其氮排放速率的差異，以做為未來設計和優化養殖循環水系統參考依據，並應用於複合式養殖和養殖管理。點帶石斑魚50 g和600 g，其每單位餵食下的總氨氮排放量分別為3.59和1.45 mg TAN/g feed，排泄氮佔攝食氮分別約14.5%和15.1%，龍膽石斑體重164 g、243 g、359 g，其每單位餵食下的總氨氮排放量分別為11.86、12.20和7.11 mg TAN/g feed，排泄氮佔攝食氮分別約11.3%、15.4%和14.3%，此兩種石斑魚氨氮佔排泄氮約75-85%，在處理系統中氨氮為優先處理對象。兩種石斑魚在日夜間每小時排氨速率有顯著差異(p<0.05)，此結果也表明，氨氮的累積主要集中在餵食後的前12個小時，最大總氨氮排放速率會出現在6-10小時。本研究建立出不同體重點帶石斑魚和龍膽石斑魚的氮排放速率，在餵食後的4-10小時，要加強氨氮處理效率，以免過高的氨累積在水體。

The two of grouper species, Epinephelus coioides and Epinephelus lanceolatus are often to see in aquaculture in Taiwan. They have a lot of advantages about their high price, high feed conversion rate, high growth rate, and good to eat, but there are less studying about nitrogenous excretion rate in different weight of Epinephelus coioides and Epinephelus lanceolatus. We investigate the nitrogenous excretion rate of different weight of Epinephelus coioides and Epinephelus lanceolatus. These data help the aquaculture engineer to design and optimize the recirculating aquaculture system and provide the polyculture to make the best production and effective aquaculture management. In Epinephelus coioides, the per day per kg weight of ammonia excretion rate are 60.1 and 43.5 mg mg TAN kg-1d-1, and per g feed per TAN mg are 3.59 and 1.45 mg TAN/g feed, and nitrogenous excretion account for nitrogen intake about 14.5 and 15.1%, at 50 g and 600 g, respectively. In Epinephelus lanceolatus, the per day per kg weight of ammonia excretion rate are 43.9, 62.8 and 62.8 mg TAN kg-1d-1,and per g feed per TAN mg are 11.86, 12.20, 7.11 mg TAN/g feed, and nitrogenous excretion account for nitrogen intake about 11.3, 15.1 and 14.3%, at 164 g , 243 g and 359 g, respectively. Ammonia accounted for nitrogenous excretion about 75-85%. There have significant difference (p<0.05) between the light phase and the dark phase of hourly ammonia excretion rate in Epinephelus coioides and Epinephelus lanceolatus.These data show that ammonia will accumulate during 12 hours after feeding and the maximum total ammonia excretion rate will occur in 6-10 hours. We establish the nitrogenous excretion rate in different weight of Epinephelus coioides and Epinephelus lanceolatus. We suggest that should arise the efficiency of ammonia removal rate in recirculating aquaculture systems at 4-10 hours after feeding to prevent the higher ammonia accumulate in the water.