Protein replacement with dried distiller's grain with solubles (DDGS) in practical diet of common carp (Cyprinus carpio)

A 12-week feeding trial was conducted to evaluate the effects of feeding corn DDGS to juvenile common carp (Cyprinus carpió L.) (initial weight 63.1±11.4 g) in controlled rearing conditions with stocking density of 30 ind/m3. Three iso-nitrogenous (35%) and iso-lipidic diets (6%) were formulated with DDGS inclusion levels of 0%, 20% and 40%. Growth parameters, nutrient and protein utilization, body composition, biochemical and histological parameters were examined at the end of trial. C. carpió demonstrated significant advantages for groups fed with DDGS-containing feeds compared to the control in most of the measured parameters (FBW, WG, FCR, PER, PPV). Protein efficiency ratios were significantly different between all groups, and the highest efficiency (1.68 g/g) was found in the DDGS 40 group. The examined fish did not showed differences in biometric indices and in biochemical parameters related to metabolic injuries, irrespective of the dietary composition. The highest deposition for oleic acid (18:1n-9) in the liver was observed in the DDGS 00 group by contributing to up 40% of the lipids. Our results showed that conventional sources of plant protein can be substituted with DDGS (up to 40%) without negative consequences on the growth and health of common carp.