Studies On Requirements Of Dietary Vitamin A, D And K For Grass Carp (Ctenopharyngodon Idellus) Fingerling

This paper was done to investigate dietary vitamin A, D and K requirement for grass carp (Ctenopharyngodon idellus) fingerling. The contents are as follows:1. Studies on the requirement of dietary vitamin A for grass carp fingerlingA 12-week growth study was conducted to determine the dietary vitamin A requirement for grass carp fingerling. Eight semipurified diets containing 0, 810, 1620, 2520, 3224, 3980, 7950 and 16386IU vitamin A (as retinyl acetate)/kg diet were fed thrice daily to triplicate groups(40 fish/group) of fish (initial weight 10.79±0.52g) in 410L plastic tank. Water temperature ranged from 20.0 to 28.0℃. The results showed that: Fish fed the diet without vitamin A exhibited a few cases of deficiency signs, such as exophthalmos, haemorrhages on the skin overlaying the base of the caudal fin, skeletal deformities. None of these deficiency signs were observed in fish fed the vitamin A supplemented diets. Weight gain rate and special growth rate increased with increasing dietary vitamin A level 0 up to 1620IU/kg. When dietary vitamin A exceeded 3980IU/kg, weight gain rate and special growth rate had a significantly decreased. The analyses of serum parameters showed that alkaline phosphatase(AKP), glutamate transaminase(ALT) and aspartate aminotrasferase (AST) were all significantly affected by dietary vitamin A. Brokenline regression analysis showed that grass carp fingerling require a minimum of 1653 IU vitamin A/kg diet for maximal growth.2. Studies on the requirement of dietary vitamin D for grass carp fingerlingThe objective of this study was to determine the dietary vitamin D requirement of grass carp fingerling. Triplicate groups of fish (initial weight 3.86±0.34g) were fed semipurified, casein- defatted soybean meal-based diets containing one of seven levels of vitamin D (0, 100, 200, 500, 1000, 2000, 3000IU kg^-1 diet) for 8 weeks. The results showed that: weight gain rate, special growth rate, feed conversion rate and survival rate were not significantly affected by the dietary treatments (P＞0.05). No differences were found in moisture, lipid and protein of the carcass related to different dietary levels of vitamin D (P＞0.05). Ash content, composition of calcium and phosphorus were significantly affected by the vitamin D(P＜0.05). Phosphorus and the activity of alkaline phosphatase in serum were increased with the level of dietary vitamin D(P＜0.05), while the serum calcium was not affected. It is proposed that the requirements of grass carp fingerling for vitamin D is about 1000IU/kg diet.3. Studies on the requirement of dietary vitamin K for grass carp fingerlingThe experiment was conducted to determine the effects of dietary vitamin K on growth, carcass composition and haematology and coagulation time for grass carp fingerling. Seven semi-purified diets were formulated to provide a series of graded levels of menadione sodium bisulfite (MSB) (0, 0.5, 1.0, 2.0, 5.0, 10.0 and 20.0 mg kg^-1 diet). Grass carp fingerlings of similar size (initial weight 3.47±0.23g; mean length 6.89 cm) were distributed in a flow-through system using a completely randomized design with seven treatments and three replicate groups per treatment. Fish were hand-fed the appropriate diets third daily at 8:00, 12:00, 16:00 for a 11-week period. Survival, growth, carcass composition and serum calcium, serum phosphorus were not significantly affected by the dietary treatments (P＞0.05). Haematology and coagulation time related to dietary level of vitamin K were found. Vitamin K deficiency prolonged blood coagulation time. It is proposed that the requirement of grass carp fingerling for vitamin K is about 1.9mg/kg diet.