Use of Duckweed, Lemna minor, as a Protein Feedstuff in Practical Diets for Common Carp, Cyprinus carpio, Fry

The use of dried duckweed, Lemna minor, as a dietary protein source for Cyprinus carpio common carp fry reared in baskets was the topic of investigation in this study. Five diets with similar E:P ratios were fed to common carp fry with an average initial weight of 0.29 g for 90 days. A diet containing 5%, 10%, 15%, or 20% duckweed was substituted for the commercial 32% protein control-group diet, fed in normal rations to common carp. There was no significant difference between the growth performance of fish that were fed diets containing up to 20% duckweed and fish that were fed the control diet (P>0.05), except for the group of fish on the 15% duckweed diet. Also, no significant difference was observed among treatments with respect to feed utilization (P>0.05). While carcass lipid content increased, protein content of the fish fed a diet of 15% duckweed decreased compared to other groups (P<0.05). The results showed that a diet consisting of up to 20% content could be used as a complete replacement for commercial feed in diet formulation for common carp fry.