Effects of floating bed coverage rate in aquaponics system on feeding rate of Carassius auratus red Variety

In order to study effects of aquaponics system of Carassius auratus red Variety- Ipomoea aquatica Forssk on feeding rate of Carassius auratus red Variety, Ipomoea aquatica Forssk floating bed coverage was 0（group A, control group）, 30%（group B）and 50%（group C）, and 3 replicates were set up in each group．Feeding rate was calculated every 5 days as a feeding rate cycle．On the 25th day, water samples were taken to detect water quality indexes including total ammonia nitrogen（TAN）, nitrite nitrogen（NO₂⁻-N）and nitrate nitrogen（NO₃⁻-N）．Results showed that there was no significant difference in feeding rate among groups A, B and C in the first and second phases of experiment（P>0.05）．In the third phase, feeding rate of groups B and C was higher than that of group A, among which, group C > group B > group A（P>0.05）．In the fourth phase, feeding rate of group C was significantly higher than that of groups A and B（P<0.05）, and that of group B was higher than that of group A, but difference was not significant（P>0.05）．In the fifth phase, there were significant differences in feeding rate among all groups, group C > Group B > group A（P<0.05）．TAN concentration was group C > group B > group A（P<0.05）．Concentrations of NO₂⁻-N and NO₃⁻-N were group C > Group B > group A（P>0.05）．Weight gain rate of Carassius auratus red Variety and specific growth rate of fish in groups B and C were significantly higher than those in group A（P<0.05）, and growth rate of length of Ipomoea aquatica Forssk in group C was significantly higher than that in group B（P<0.05）．In conclusion, aquaponic system was more beneficial to increase feeding rate of Carassius auratus red Variety, and the 50% floating bed coverage system was more beneficial to increase feeding rate of Carassius auratus red Variety．