Evaluation of Calanus finmarchicus copepod meal in practical diets for juvenile Atlantic halibut (Hippoglossus hippoglossus)

The copepod, Calanus finmarchicus, has potential as a new ingredient in practical feeds for marine fish. Two experiments were conducted to evaluate the nutritional value of C.finmarchicus meals when fed to juvenile Atlantic halibut. The first study determined protein, lipid and energy digestibility coefficients of four C.finmarchicus meals prepared under different processing conditions. The second study evaluated growth and nutrient utilization efficiency of juveniles fed diets containing varying proportions of fish meal, plant meals and C.finmarchicus meal. Moisture, ash, protein, lipid and gross energy contents of the C.finmarchicus meals were 28-93, 74-138, 505-648, 123-269gkg(-1), and 21-26MJkg(-1), respectively. Protein, lipid and energy digestibilities of C.finmarchicus meals were 91-99%, 90-95% and 90-99%. The digestibilities significantly decreased for the Calanus meals processed at higher temperatures. During the growth study, halibut fed a diet containing 240gkg(-1)C.finmarchicus meal had significantly higher weight gain and growth rate than all other groups. Nitrogen and energy retention efficiencies ranged between 35-45% and 33-43%, and were significantly higher for fish fed 160-240gkg(-1)C.finmarchicus meal than for fish fed plant protein and control diets. The results indicate that growth and nutrient utilization efficiency are improved in Atlantic halibut fed diets supplemented with C.finmarchicus meal.