Effect of different levels of dietary lipids in extruded feeds on the rearing results of carp fry (Cyprinus carpio L.) cultured in cooling water

Abstract

Carp of the initial individual weight of 30 g/ind. (±5 g) were fed for 83 days with three kinds of extruded, isoprotein (47.5%) feeds differing in the lipid content (9.1%, in feed A, 12.9% in feed B, and 17.0% in feed C). The main source of the lipids was a poultry fat. After the completion of the experiment the following values of the Specific Growth Rate, SGR index were achieved (respectively): 2.45, 2.75, 2.59% The values of Food Conversion Ratio, FCR were as follows: 1.27, 1.10, 1.21, while the Energy Retained index was respectively: 23.7, 29.6, and 26.6%. In the present experiment consisting in feeding the carp fry in the conditions of cooling water at 13.1-31.2°C, the most favourable results of rearing were achieved using the extruded feed containing12.9% of lipids. The lipids consisted of 2/3 of poultry fat and 1/3 of structural fish fat.