Effect of Aquatic Plants as a Biofilter on Water Criteria and Common Carp Growth Performance in Aquaculture Intensive System

Abstract

The experiment was conducted in the field of the College of Agriculture, University of Tikrit, for the period from 14/6/2022 to 14/8/2022 inside a semi-exposed building (gable) with four treatments. Each treatment included three replicates, and each replicate included (6) fishes in a closed bio-aquatic system, by weight 14.15±1.22, 13.8±0.72,13.9±0.78, 13.7±0.93g for T1, T2, T3 and T4 in 12 ponds respectively. On a filtration tank representing the biological and mechanical filter in an intensive aquatic system with a capacity of 100 liters each, three aquatic plants were grown (lentils, Azolla, Ceratophylom), except for the control treatment, which was similar to all treatments except for the presence of aquatic plants. The water was treated in a mechanical filter unit through thick sponge layer, then directing the water to the biological treatment by means of crushed gravel, in addition to the aquatic plants to filter the dissolved organic pollutants. The results showed a significant effect of aquatic plants at (p ≤0.05) on dissolved oxygen DO (mg / liter), pH, total dissolved salts (TDS), nitrate NO3, nitrite NO2, and ammonia. The biological characteristics of aquatic plants are impacted by modifications to the physicochemical properties of the water. There was a significant improvement in weight gain (G.W), relative growth (RGR), specific growth of fish (SGR), and feed conversion efficiency (FCR) for treatments T2, T3, and T4 compared with control treatment. There was a significant difference when using aquatic plant in the percentage of protein compared to the control treatment. No significant differences were observed on blood biochemical parameters. While the result of the correlation or interactions between water characteristics with growth parameters for Common carp fish showed significant effects at a significant level (P ≤0.05) and (P ≤0.01).