ABSTRACT
Since most fish lack the ability to biosynthesize ascorbic acid (AA), or if they have the capability to synthesize the vitamin, the quantity produced is insufficient to meet metabolic needs, AA must be provided in the diet. Also, since AA is an essential dietary component that functions in numerous met abolic processes, considerable research has been conducted concerning its role in the nutrition of fish. Diets devoid of AA result in prominent defi ciency signs in fish. Most notable are spinal deformities, particularly scoliosis and lordosis. Often abnormalities of the cartilage of the eye, gill, gill opercula, and fins are observed in AA-deficient fish, as well as reduced ap petite, slow growth, internal and external hemorrhage, fin erosion, and ane mia. The minimum amount of AA required in the diet needed for normal growth and health of fish generally ranges from 10 to 50 mg/kg of diet. The requirement varies among fish species, but intraspecies differences such as fish strain, size, and age also affect the dietary requirement. The amount of AA that must be added to the diet for normal function is also affected by the abundance of natural food organisms found in pond water and by the form of the vitamin that is added to the diet. Considering that ingredients typi cally used in commercial fish feeds are essentially devoid of AA and further considering that processing these ingredients into fish feed pellets requires conditions of high pressure, heat, and moisture, AA must be added, not only
The manuscript is approved for publication as Journal Article No. J-9435 of the Mississippi Agricultural and Forestry Experiment Station (MAFES), Mississippi State University. This project is supported under MAFES Project Number MIS-0822.
