J. Appl. Ichthyol. 22 (Suppl. 1) (2006), 283-286© 2006 Blackwell Verlag, BerlinISSN 0175-8659
Received:March,15,2006 Accepted:August20,2006
U.S. Copyright Clearance Centre Code Statement:
0175-8659/2006/2202-132$15.00/0
Summary
The objective of this study was to determine the effects of dietaryvitamin C on growth, blood, body chemical composition and alka-line phosphatase (ALP) activity in juvenile great sturgeon (
Husohuso
) fed different levels of dietary vitamin C. 5-month old greatsturgeon were fed diets supplemented with 0, 100, 200, 400, 800and 1600 mg ascorbic acid/kg diet for 16 weeks at 20°C. No exter-nal symptoms of scurvy developed in the vitamin C-free group. Nosignificant differences in hematocrit (PCV) and hepatosomaticindex (HSI) were observed (
p>0.05
). Dietary vitamin C supple-ment resulted in significant increases of final body weight andweight gain (
p<0.05
). Also, dietary vitamin C affected hemoglobin(Hb) significantly (
p<0.05
). The average of ALP was not affected by dietary treatment after 16 weeks (
p>0.05
), but the lipid contentand ash of body composition was significantly affected by vitaminC in the diets, (
p<0.05
). The results suggested that in means of ability of synthesis of this vitamin in sturgeon fish, it is insufficientin artificial rearing conditions and must add to the diet especially inearly life stages.
Introduction
Sturgeon fishes are valuable species, which are currently highlyendangered. The rearing of these species has seen considerable progress in past years. Great sturgeon or Beluga (
Huso huso
) is oneof the sturgeon species with high growth rates and appears to bevery suitable for aquaculture, however, little information about thenutrient requirements is presently available (Hung and Deng,2002).Vitamin C or ascorbic acid is an essential vitamin for many spe-cies of fish as a co-factor in various hydroxylation reactions in liv-ing tissue, and is involved in collagen formation, growth andreproductive processes as well as disease resistance and immuneresponse (Li and Robinson, 1999). It also acts as an importantwater-soluble antioxidant (Sandnes, 1991). Ascorbic acid is, how-ever, one of the most labile vitamins and is easily oxidized by air,heat, enzymes, and multivalent cations. Loss of supplementedascorbic acid in fish diets during processing and storage has beenreported (Waagbo et al., 1991; Anderson and Sunderland, 2002).More stable ascorbic acid derivatives with vitamin C activity, like phosphate derivates, are now widely used in fish feeds. Most cul-tured fish require vitamin C, because they are unable to synthesizeit (NRC, 1993; Papp et al., 1995; Dabrowski, 2001), but contro-versy surrounds the ability of primitive teleost fish to synthesizeascorbate (Dabrowski, 1990; Moreau et al., 1999a; Hung andDeng, 2002) for present of L-gulono-1, 4-lactone oxidase, a keyenzyme for convert of glucose to ascorbic acid.Today, there are many researches about effects of vitamin C ongrowth, tissue storage, disease, and stress resistance in many spe-cies (Dabrowski, 2001). While there is little documented evidenceabout the effects of this micro-nutrient on sturgeons, there is noinformation about the effects of ascorbic acid on carcass composi-tion, growth and physiological parameters such as alkaline phos- phatase (ALP) activity, hemoglobin (Hb) and hematocrit (PCV)values in great sturgeon. To determine the vitamin C requirementof fish species, the first step has to be the study of its effect on thegrowth performance and physiological roles. Thus, the purpose of this experiment was to determine the effects of different levels of vitamin C on growth, mortality, tissue chemical composition, and physiological status in juvenile great sturgeon.
Materials and methods
Feeding trials
Four-months old great sturgeons from the Shahid Beheshti Hatch-ery (Guilan, Iran), were used. Prior to the feeding trials, fish werefed an ascorbic acid free diet for 4 weeks to adjust their status tothe experimental diet. Fish averaging 38.0 ± 0.5g were distributedto each tank in groups of 55 fish in 18 tanks (completely random-ized design) and fed the experimental diets after acclimation intriplicates for 16 weeks (Table 1). The kind of vitamin C was L-
Effects of dietary vitamin C supplementation on performance, tissue chemicalcomposition and alkaline phosphatase activity in great sturgeon (
Huso huso
)
การแปล กรุณารอสักครู่..
