Does the supplemental feed type used for carp nutrition influence on mentum deformities in Chironomus plumosus larvae?

Abstract

Supplemental feeding of carps reared in semi-intensive production system can cause changes in water quality which initiates changes in fish biocenosis, affecting other living organisms. We monitored the influence of different supplemental feed types used for carp fry on mentum deformities in Chironomus plumosus larvae, and the influence of carp as a predator on this phenomenon. The study was conducted in carp ponds at the Centre for Fishery and Applied Hydrobiology “Little Danube” (CEFAH), Experimental Station Radmilovac, Faculty of Agriculture, University of Belgrade, through four different treatments (A-D) lasting three months. Two commercial feed types (arranged in four treatments) were used for carp nutrition: Soprofish 25/7 and Omega 3-32/7. Chironomus plumosus larvae were collected prior to the experiment (control), in the middle of the experiment and at the end of the experiment. According to analysis of mentum deformities, the percentage of deformities was the same in the middle and at the end of the experiment in treatment A (10 %), while in treatment B and C the percentage of deformities decreased at the end of the experiment. Considering treatment D, where the fish were fed with Omega 3-3/27 feed during the entire period, the percentage of deformities decreased to the end of the experiment (6.6 %). In carp ponds where the fish were fed with Omega 3-32/7 feed, lowest percentage of mentum deformities in chironomids larvae indicate that carp consumed natural feed to a lesser extent. Actually, the most of their nutritional need they met with high quality supplemental feed.