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利用生物絮团的原理,探讨了养殖水体中添加碳源对水质及罗非鱼Oreochromis niloticus生长的影响。试验分A、B、C 3个处理组和1个对照组,在室外水泥池中饲养体质量为(10.5±0.2)g的新吉富罗非鱼,各组投喂同种商品饲料,其中对照组投喂正常量(日投饲量为鱼体总质量的8%～10%),A组投喂正常量,B组投喂正常量的80%,C组投喂正常量的75%,且A、B、C组水体中同时泼洒饲料投喂量30%的小麦淀粉(用池水混匀泼洒),而对照组不泼洒小麦淀粉。试验共进行36 d,分6次检测养殖池水质,并分析罗非鱼的生长性能、饲料系数和蛋白质效率。结果表明:整个试验期间,C组水体中总氨氮(NH4+-N)、亚硝酸盐(NO2--N)含量的平均值显著低于对照组(P<0.05);A、B、C组水体中硝酸盐(NO3--N)、总氮(TN)、总磷(TP)和叶绿素a含量的平均值均低于对照组(P>0.05),而絮体体积、悬浮物和异养细菌总量的平均值均高于对照组(P>0.05);A组罗非鱼的增重率和特定生长率均高于对照组(P>0.05);B组和C组鱼的饲料系数分别比对照组显著降低了12.96%和17.04%,而蛋白质效率分别比对照组显著提高了14.91%和21.04%(P<0.05)。本研究表明,养殖水体中添加小麦淀粉作为碳源,可降低三态氮含量,改善水质,并生成鱼类可食用的絮团,降低饲料系数。
The principle of biological flocculation was used to investigate the effect of adding carbon source on the water quality and the growth of Oreochromis niloticus in tilapia. Tests were divided into three groups (A, B and C) and a control group. The fresh tilapia fillets with the body weight of (10.5 ± 0.2) g were fed in the outdoor cement pool, and all the groups were fed the same kind of commercial feed, The rats in group A received a normal dose of 80% of the normal dose and those in group C fed 75% of the normal dose, while those in the normal group fed a normal dose of 8% -10% of the total mass of the fish. In Group A, B and C, wheat starch (30% of the total amount of feed) was sprinkled in the water of the groups A and B while the control group did not sprinkle wheat starch. The experiment was conducted for 36 days and the water quality of aquaculture ponds was tested 6 times. The growth performance, feedstuff coefficient and protein efficiency of tilapia were also analyzed. The results showed that the average values of NH4 + -N and NO2 - N in group C were significantly lower than those in control (P <0.05), while those in groups A, B and C The average contents of NO3 - N, TN, TP and chlorophyll a were lower than those of the control group (P> 0.05). The floc size, suspended matter and heterotrophic bacteria (P> 0.05). The weight gain rate and specific growth rate of tilapia in group A were higher than those in control group (P> 0.05). The feed coefficients of fish in group B and group C were respectively Which was significantly lower by 12.96% and 17.04% than the control group, while the protein efficiency was significantly increased by 14.91% and 21.04% (P <0.05), respectively, compared with the control group. This study shows that the addition of wheat starch as a carbon source in aquaculture water can reduce the three-state nitrogen content, improve water quality and produce fish edible flocs, reducing the feed efficiency.