Effects of Biological Flocs on Growth Performance of Cyprinus carpio var.Furui No.2 and Aquaculture Water Quality

[Objectives]To study the effects of biological flocs on growth performance of Cyprinus carpio var.Furui No.2 and aquaculture water quality.[Methods]The comparative experiment method was adopted.An experimental group and a control group were set up,with 3 replicates in each group.The experimental group used beet molasses as the carbon source which was added once a week.The breed,quantity,and specifications of stocked fish in each group were exactly the same.The experiment lasted for 60 d.Fish growth indicators were measured every 7 d.After one week of the experiment,ammonia nitrogen and nitrite were monitored once a week,and dissolved oxygen was monitored once a day.[Results]The survival rate of fish,the average weight of,the weight gain rate,and the specific growth rate of the experimental group were significantly higher than those of the control group(P<0.05),and the feed conversion rate was significantly lower than that of the control group(P<0.05).One week after adding the carbon source in the experimental group,the ammonia nitrogen was lower than the control group,and after three weeks it was significantly lower than the control group(P<0.05);after adding the carbon source,the nitrite in the experimental group was lower than the control group,there was no significant difference in the first three weeks(P>0.05),and there was a significant difference after three weeks(P<0.05).The feed conversion rate of the experimental group was significantly lower than that of the control group(P<0.05).[Conclusions]Adding a carbon source can significantly reduce ammonia nitrogen,nitrite and other toxic and harmful substances in the aquaculture water,promote the growth of aquaculture fish and increase the feed utilization rate.