Nutritional Physiology Of Several Vitamins And Protein Sources Development For Japanese Seabass, Lateolabrax Japonicus C. And Large Yellow Croaker, Pseudosciaena Crocea R.

Feeding trials were conducted to investigate the nutritional physiology of several vitamins and the potential of several protein sources as replacement of fish meal for Japanese seabass, Lateolabrax japonicus C. and large yellow croaker, Pseudosciaena crocea R. The researches of vitamins for juvenile Japanese seabass and large yellow croaker were conducted in indoor flow-though culture system. The studies on protein sources were conducted in sea floating cages (1.0×1.0×1.5 m or 1.5×1.5×2.0m). Results of the present study are presented as follows:1. A 9 - week feeding experiment was conducted to estimate the effect of dietary vitamin A levels on growth and serum biochemical parameters for juvenile Japanese seabass, Lateolabrax japonicus. Six isonitrogenous (43% crude protein) and isoenergentic (20KJ g-1 dry matter) purified diets (Diets 1 - 6) containing 245, 1005, 1835, 3781, 7583 and 15273 IU vitamin A (supplied as retinyl acetate) per kg diet were fed twice daily to triplicate groups (10 fish / group) of fish (initial weight 10.20±0.14 g / fish) in 120 L plastic tanks. Water temperature ranged from 27.0 to 30.0℃, salinity from 25 to 28‰, pH from 8.0 to 8.1 and dissolved oxygen content was approximately 7 mg L-1 during the experiment. Fish fed the basal diet (Diet 1, 245 IU vitamin A / kg diet) developed heavy mortality, exophthalmos and haemorrhages at the base of the fins. None of these deficiency signs were observed in fish fed the vitamin A supplemented diets (Diets 2 - 6). Weight gain (WG), specific growth rate (SGR), feed efficiency ratio (FER) and protein efficiency ratio (PER) increased with increasing dietary vitamin A level up to 1835 IU / kg diet, and thereafter, level off. Liver vitamin A concentration in the fish increased with increasing dietary vitamin A level up to 3781 IU / kg diet (Diet 4), and thereafter,...