Effect of feed protein level on water chemical and technological parameters of a recirculating aquaponics system for carp ( Cyprinus carpio L.) and lettuce ( Lactuca sativa L.) farming

摘要

Aquaponics is a system integrating hydrobionts farming with cultivation of plant species (vegetables, spice herbs, flowers etc.). The aim of the present study was to establish the effect of feeds with different protein content (24% and 28%) on water chemical and technological parameters of a recirculating aquaponic system for carp (Cyprinus carpio L.) and lettuce (Lactuca sativa L.) farming. The experiment was conducted in 2 variants, each of 30-day duration, comprising feeding carps with pelleted feed either with 24% crude protein or 28% crude protein, with pellet size of 3.5 mm. Each of variants comprised 12 fish with uniform initial weight (563±0.1 and 0.566±0.3 g respectively), without significant difference (P≥0.05) and 17 plants in 2nd germination week. In fish growth performance traits at the end of experiments showed higher body weight in carps in the variant with 28% dietary protein (by 4.4%) and total body length (by 1.4%) as compared to those with 24% dietary protein. Fish fed feed with higher dietary protein level exhibited lower feeding coefficients vs those fed 24% protein (by 13.04%). The lettuce biomass and the length of their root system by the end of the trial were higher in the experimental variant with 28% crude protein.