不換水白蝦 (Litopenaeus vannamei)養殖技術
不換水白蝦 (Litopenaeus vannamei)養殖技術之建立
本試驗在隔離病毒的環境下，以不換水的方式養殖白蝦，以探討其最佳養殖方法。各試驗組之養殖密度除了密度實驗之外，皆為100尾/m2。結果顯示，養殖池加裝簡易的隔離設施養殖不帶病毒的蝦苗即可以避免白蝦感染病毒。養殖83天後，不換水組的活存率、末重、產量與成長率 (90.7%, 16.8 g, 1.52 kg/m2, 1.36 g/week)與換水組無顯著差異，不過FCR卻較低 (p<0.05)。添加黑糖可增加白蝦的末重、成長率並降低FCR (18.6 g, 1.60 kg/m2, 1.64 ± 0.04) (p<0.05)，但是會抑制硝化作用效率。掛網以2張組白蝦的末重、產量最高，FCR最低 (p<0.05)。底砂可增加白蝦的末重、產量與降低FCR (p<0.05)，以及穩定pH和增加脫氮作用效率。鹽度以25 ppt組白蝦的末重、產量最高，FCR最低 (p<0.05)。養殖密度以200尾/m2組白蝦的末重最高，FCR最低 (p<0.05)，並且產量為100尾/m2的兩倍。養殖結束時，37% 蛋白質與32% 蛋白質飼料兩組的水質條件無顯著差異，不過37% 蛋白質組白蝦的末重較高，FCR較低 (p<0.05)，產量也多出26%。由以上結果可知，不換水養殖不但可以降低白蝦遭受病毒感染的風險，而且只要充分打氣使固體物保持懸浮，即可維持良好的水質。因此，不換水養殖除了可以減少抽水電力與用水量之外，尚有增加產值與降低飼料成本的益處。
Establishment of zero-water exchange cultivation technology in the white shrimp, Litopenaeus vannamei
White shrimp (Litopenaeus vannamei) were cultured in isolated environment using zero-water exchange to investigate optimum cultivation method. Except density experiment, culture density was 100 shrimps/m2 in all other experiments. The results indicated that simple quarantine facility could prevent virus infection of pond shrimps. After 83 days of cultivation, survival rate, final weight, yield and growth rate (90.7%, 16.8 g, 1.52 kg/m2, 1.36 g/week) of zero-water exchange group was not significantly different from those of water exchange group, but FCR was lower (p<0.05) instead. Addition of brown sugar increased final weight and growth rate of shrimp and lowered FCR (18.6 g, 1.60 kg/m2, 1.64 ± 0.04) (p<0.05), but nitrification was inhibited. Application of two mats per tank gave highest increases in final weight and yield and lowest FCR (p<0.05). Bottom sand increased final weight and yield and lowered FCR (p<0.05), stabilized pH and increased de-nitrification efficiency. Salinity of 25 ppt had highest final weight and yield and lowest FCR (p<0.05). Density of 200 shrimps/m2 had highest final weight and lowest FCR (p<0.05) and yield twice as that of density of 100 shrimps/m2. At the end of cultivation, water quality condition between 37% and 32% protein feed were not significantly different. But, the shrimps of 37% protein feed had higher final weight, lower FCR (p<0.05) and 26% more yield. The above results indicated that the risk of shrimps infected by virus could be prevented using zero-water exchange culture method. As long as solid was held suspending by sufficient agitating, good water quality could be maintained. Hence, zero-water exchange culture could not only decrease electricity of water pump and quantity of water use, but also increase the value of product and incorporation efficiency of feeds.
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