投餌量和換水對輪蟲連續生產的影響

Abstract

輪蟲是一種重要的水產開口餌料生物，由於其體型小而難以換水，傳統的批次養殖密度低且不穩定，新興的循環水連續生產系統則因為持續少量換水而浪費飼料。本研究研製可快速換水的旋轉滾筒和輪蟲連續生產技術，目標是提高飼料效率，創造容易操作、低成本、高生產彈性的高密度輪蟲連續生產系統。本研究探討投餌量和換水對連續生產的影響，使用3個水量為100L的玻璃缸進行三重複試驗，輪蟲(Brachionus plicatilis)起始密度500 ind./ml，試驗組每天用旋轉滾筒換水80L，每天投餌90g或60g，對照組每天用滾筒不旋轉換水至堵塞為止，每天投餌60g，使用史派克(S. parkle)人工飼料，每天在換水後投預定量的40%，之後用蠕動泵浦投餵剩餘飼料22小時，至24小時進行換水。試驗海水鹽度預先調為5 psu，用加溫棒控制溫度在30°C，用純氧機維持DO在5 ppm以上，用pH控制器控制pH在7.0 ± 0.1，每次試驗進行14天，每天以人力管理一次，進行取樣、收穫、換水和清潔並記錄所花時間。試驗結果90g組在第3天達到1500 ind./ml，60g及對照組在第2天達到1000 ind./ml，之後每天收穫30%。平均收穫量:90g組57.8 x10⁶ 隻、60g組40.2 x10⁶ 隻、對照組40.2 x10⁶隻，收穫量與投餌量成正比。三組水中殘留飼料量皆隨時間遞減，至第24小時達最低點，實際投餵飼料量為90g組:89.17g、60g組:59.36g、對照組:59.12g。節省飼料率:90g組:99%、60g組:98.9%、對照組:98.9%，阿摩尼亞平均濃度:90g組:0.25 ppm、60g組0.18ppm、對照組0.41ppm。飼料轉換率:90g組:1.54g、60g組:1.48g、對照組:1.48g。試驗組每天管理一次，包括取樣、換水、投餌、收穫、清潔，90g組與60g組約需45min，對照組約30 min。估計本系統的養殖密度可以達到3000 ind./ml，且可以用投餌量調控。相較於高密度循環水連續生產系統，本系統具有容易操作、低成本、以彈性的生產量等優點。

Rotifers are an essential feed for many species of larvae in aquaculture. Due to their small size, it is difficult for water to change. Traditionally, breeding density is low and unstable. This study developed a novel recirculating system of rotifers rearing, with a rotating drum and a continuous production technology for quick water changing rate. Also, this system can improve feed efficiency and product density. This study investigated the effect of feeding amount and water change rate on continuous production. Three glass tanks with a water volume of 100 L were used for three replicate experiments. The initial density of rotifers (Brachionus plicatilis) was 500 ind./ml. Each group used a rotating drum to change the water every day. 80L, feeding 90g or 60g per day, the control group used the drum to change the water without rotation until it was blocked, providing 60g per day. The results showed that the 90g group reached 1500 ind./ml on the 5th day, and the 60g and control groups reached 1000 ind./ml on the 4th day. The average harvest amount was 57.8x10⁶ per day in the 90g group, 40.2x10⁶ per day in the 60g group, and 40.2x10⁶ per day in the control group. The amount of residual feed in the three groups decreased with time and reached the lowest point at the 24th hour，The actual feeding amount of rotifers is in the 90g group87.14g, 56.36 in the 60g group, 56.12g in the control group，The concentration of ammonia was 0.25 ppm in the 90g group, 0.18ppm in the 60g group, and 0.41ppm in the control group. Feed conversion ratio were maintained at 90g: 1.54g, 60g: 1.26g control group: 1.46g.，Save feed ratio 90g: 99%、60g: 98.9%、control group: 98.9%。The experimental group was managed daily, including sampling, water change, feeding, harvesting, and cleaning. It took about 45 minutes for each tank and 30 minutes for the control group. It is estimated that the breeding density of this system can reach 3000 ind./ml, and the feeding amount can control it. Compared with the high-density circulating water continuous production system, the system has the advantages of easy operation, low cost, and flexible production volume.