Author(s): Nweke SU, Ugwumba AAA
Clarias gariepinus fingerlings (mean weight =2.77g ± 0.33) were fed eleven (11) diets of about 36% crude protein with different inclusion levels (0% i.e. control diet, 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, 90% and 100%) of duckweed (Lemna paucicostata) meal as replacement for fish meal for ten (10) weeks. All experimental diets were accepted and utilized for growth by the fingerlings. The results showed that growth rate and nutrient utilization were better for the control diet (0% duckweed inclusion) compared to those fed duckweed diets. The weight gain (1.49g/fish) relative (522%) and specific (1.1%) growth rates were highest in fish fed control diet. Among the duckweed-based diets 10% and 50% inclusion levels had the best specific growth rates of 0.98% and 0.85% respectively. There was no significant difference between the specific growth rate of the control diet, 10% and 50% duckweed inclusion diets. The food conversion efficiency (51.5%) and protein efficiency ratio (1.41) were also best in fish fed control diet. The food conversion efficiency of the 10% and 50% duckweed-based diets were about 48% and 46%respectively. The protein efficiency ratio of 10% (1.31) and 50% (1.28) duckweed-based diets were also better than the other duckweed-based diets. There was also no significant difference between the protein efficiency ratio of the control diet, 10% and 50% duck weed-based diets. Therefore duckweed can partially replace fishmeal in the diet of C. gariepinus. For adequate growth and nutrient utilization, duckweed can replace fishmeal up to 50% level of inclusion.