Requirement of Grass Carp Fingerlings for .ALPHA.-Tocopherol.

Abstract

This experiment was intended to identify the vitamin E (VE)-deficiency symptoms and to determine the requirement of grass carp Ctenopharyngodon idella for α-tocopherol. For this purpose grass carp fingerlings weighing 4.5g on average were fed diets with various levels of α-tocopherol. Fish fed an α-tocopherol deficient diet showed the so-called 'sekoke disease', a similar symptom to the apparent muscular dystrophy of carp, characterized by a marked loss of flesh in the back, while also revealing high moisture and low protein contents in muscles, and the reduction of α-tocopherol content in hepatopancreas and muscle. Lordsis was also observed in fish fed the α-tocopherol deficient diet. Symptoms such as the apparent muscular dystrophy with or without lordsis started appearing from the 9th week of feeding (the 16th week from the pre-feeding experi-ment). Even though fish fed 5 and 10mg of α-tocopherol showed good growth and feed ef-ficienecy, high incidences of the apparent muscular dystrophy and lordsis were also noted. Taking into consideration the incidence of the apparent muscular dystrophy and lordsis as well as the tissue levels of α-tocopherol, it is suggested that the requirement of grass carp fingerlings for α-tocopherol is about 20mg per 100g diet.