Diet fed to brood stock effects the growth of channel catfish (Ictalurus punctatus L) fry.

摘要

In female brood stock, the fast growth of oocytes, embryonic development and early performance of fry are critically acted by the nutrient supply during vitellogenesis. During the vitellogenic phase of development, the main growth of the oocyte occurs through the uptake of extra-ovarian substances from the maternal blood (Tyler, Sumpter & Bromage 1988a, b). In rainbow trout there is decreased level of estradiol 17b and vitellogenin during fast ovary growthwhen brood stock is given a diet devoid of ascorbic acid (Waagbo,Thorsen & Sandnes 1989).Vitamin C is involved as a co-enzyme in many enzyme systems for hydroxylation of proline and lysine into the procollagen molecule that is necessary for the formation of cartilage, bones and skin and thereby contributes to growth (Barnes & Kodicek 1972; Halver1989). Thus, highvitamin C content increases survival of eggs and fry in rainbow trout Salmo gairdneri (Sandnes, Ulgenes, Brekkan & Utne1984), tilapia (Soliman, Jauncey & Roberts 1986) and Atlantic salmon (Eskelinen 1989). A low maternal intake of AA produces juvenileswith severe spinal deformities (scoliosis and lordosis) while a dietary supply of enhanced AA levels maintains an optimal performance of the fry (Soliman et al.1986).The importance of AAduring egg development has been supported by studies in mature salmonids, where ovarian deposition of this vitamin greatly exceeds deposition in other organs (Hilton, Cho, Brown & Slinger1979; Dabrowski1991).