PRODUCTS AND SERVICES TO FISH
L-ascorbic acid fine microcrystals (powder)
WATER SOLUBLE VITAMIN C
Description and nature of the product:
C-powder comprises water soluble vitamin C (L-ascorbic acid) micro-crystals in fine powder form. Either 99% of the crystals are smaller than 212 μm, or 90% of the crystals are smaller than 150μm. Solubility in water exceeds 200g per litre. The product appears as an odourless white or pale white powder like product with a density of 0.8g/cm3.
Young developing fish larvae and fry need vitamin C for the normal development of their cartilagenous tissues and skeleton. It has been found that pour supply of the vitamin to the young fish in hatcheries provoke most of the known skeletal deformities, such as those affecting the vertebrae, the opercula and jaws as well as the fins. Stress related responses are weakened and the fish are prone to disease.
Vitamin C plays a vital role in the physiological mechanisms of stress and immune responses of the nursery and caged on-growing fish. Supplementation of the fish diets with extra vit. C at intervals is recommended in order to strengthen their defences against secondary infections and their endurance to adverse weather, handling and transportation stress.
On cage farms, vitamin C supplemented diets help to speed surface wound healing in case of scale loss subsequent to fish grading or vaccination. In addition, supplementary vitamin C is required by fish suffering bacterial, viral or parasitic infections enhancing their defence mechanisms against disease.
Supplementary vitamin C is also required by active brood-stock fish in order not only to condition them, but also to increase the quality of gametes and the hatching rate of the fertilised ova.
None. Ascorbic acid is a natural antioxidant. There are no limitations as regards the duration of supplementary administration.
The normal vitamin C requirements of sea bass and sea bream range between 150-300 mg/kg of dry ration. These requirements increase by at least 30% for young fry and spawning brood-stock.
During winter, subsequent to handling stress, or during disease outbreaks the needs for vitamin C are much higher and it must be available through the diet at elevated levels, approximately 1300 mg/kg of dry ration.
C-powder is administered as a diet supplement subsequent to dilution with some fresh water, which is then sprayed on the feed. After the feed dries in air, some fish oil is used for top coating. Alternatively, it may be top-dressed on the fish feed after mixing with some fish oil.
During periods of increased vit. C demand, the usual daily supplementation rate of fish feed with vitamin C (on top of the commercial fish feed content) should be calculated to provide 7g to 10g of extra available vitamin per 100kg of fish biomass for about a week.
Recommended diet supplementation rates per 100kg of fish biomass:
For sea bream in particular, vitamin C supplemented diets are recommended throughout the winter (November through to February).
Storage and packing:
C-powder is available in 25kg carton boxes with insulated air-tight lining. It may be stored for 18 months in a dry, dark and cool (up to 25°C) environment.
The inner container should be closed firmly after each use in order to avoid oxidation, especially in humid environments. Avoid exposure to direct sun-light and never place ascorbic acid in metallic (especially iron or copper) containers.
Copyright © Dr Panos Varvarigos
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