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试验在5个循环水系统中进行,每个系统由3个40L的水族箱和1个20L的沙石生物过滤器组成。水通过一根虹吸管从水族箱排出,因重力作用回流到生物过滤器,每天换5％的去氯新水(用硫代硫酸钠中和)。温度用200-W水族箱加温器控制,保持在25～27℃。每隔两星期测一次溶氧、pH、氨氮和亚硝酸氮。饵料按Stichney等(1984)提出的饵料成分配制。饵料成分混合后,用肉糜研磨机挤出2mm直径的颗粒(NRC,1983)。经空气干燥后,饵料湿度为10～20％,-20℃冷冻贮存。饵料成分为商业化产品(u.s.Bio-
The experiment was conducted in five recirculating water systems, each consisting of three 40 L aquariums and one 20 L sandstone biofilter. Water is discharged from the aquarium via a siphon and back to the biofilter by gravity, changing to 5% dechlorinated fresh water daily (neutralized with sodium thiosulfate). The temperature was controlled with a 200-W aquarium warmer, kept at 25-27 ° C. Dissolved oxygen, pH, ammonia nitrogen and nitrite nitrogen are measured every two weeks. The feed is formulated according to the feed composition proposed by Stichney et al. (1984). After mixing the bait ingredients, a 2 mm diameter pellet was extruded with a meat mill grinder (NRC, 1983). After air-drying, bait humidity of 10 to 20%, -20 ℃ frozen storage. Food ingredients for commercial products (u.s.Bio-