The Dietary Thiamin, Riboflavin And Pyridoxine Of Gift Tilapia(Oreochromis Niloticus)

The purpose of this study was to investigate the optimum dietary thiamin riboflavin and pyridoxine requirement of GIFT tilapia on the basis of growth parameters, hepatic vitamin saturation and a vitamin-dependent biochemical function. The main results were showed as below. 1. The dietary thiamin requirement of GIFT TilapiaGIFT tilapia(initial weight 64.4±1.5 g) were fed purified diets containing six levels(0.08, 0.57, 1.13, 2.09, 4.11 and 8.09mg/kg diet) of thiamin in separate 12 weeks. The experiment was used to determine the dietary thiamin requirement of GIFT tilapia on the basis of growth parameters, hepatic thiamin saturation and a thiamin-dependent biochemical function. The results showed that, with the increasing of dietary thiamin level, weight gain rate of tilapia first increased linearly then remained nearly unchanged. Hepatic thiamin contents with the increasing dietary thiamin increased an kept unchanged when increasing to 2.09 mg/kg thiamin. Fish fed the control diet without supplementation of thiamin showed significantly higher serum pyruvate content than fish fed diets supplemented with thiamin(P<0.05), while crude protein, moisture, ash, crude lipid content in whole body had no significant differences among various treatments(P>0.05). Fish fed the diets with supplementation of thiamin showed significantly higher serum high density lipoprotein cholesterol content and hepatic transketolase expression than fish fed the control diet without supplementation of thiamin(P < 0.05). Fish fed the diet containing more than 1.13 mg/kg thiamin obtained significantly higher hepatic transketolase activity and serum T-CHO content than that of the control group. Based on broken method of the relationships between weight gain rate, hepatic thiamin contents and dietary thiamin concentrations, it can be concluded that the dietary thiamin requirement for GIFT tilapia was considered to be 1.16 and 2.06 mg/kg diet respectively. 2. The dietary riboflavin requirement of GIFT tilapiaThere were 270 GIFT tilapia and divided into 6 groups randomly, every group has three replicates, 20 fish per replicate. GIFT tilapia(initial weight 59.5±0.9 g) were fed purified diets containing six levels(0.5, 2.6, 5.4, 10.8, 20.4 and 39.7 mg/kg diet) of riboflavin in separate 10 weeks. The experiment was used to determine the dietary riboflavin requirement of GIFT tilapia on the basis of growth parameters, hepatic riboflavin saturation and a riboflavin-dependent biochemical function. The results showed that, with the dietary riboflavin level increasing, weight gain rate of tilapia first increased linearly then remained nearly unchanged. Hepatic riboflavin contents with the increasing dietary riboflavin increased and kept unchanged when increasing to 20.4 mg/kg riboflavin. Fish fed the diets with supplementation of riboflavin showed significantly lower serum TGK, T-CHO content and AST activity than fish fed the control diet without supplementation of riboflavin(P<0.05). Fish fed the diet containing more than 5.4 mg/kg riboflavin obtained significantly lower GLU content than that of the control group. Fish fed the control diet without supplementation of riboflavin showed significantly lower hepatic SOD activity than fish fed diets supplemented with riboflavin(P<0.05), while hepatic CAT activity had no significant differences among various treatments(P>0.05). With the dietary riboflavin level increasing, hepatic GR expression increase, besides Fish fed the diet containing more than 10.8 mg/kg riboflavin obtained significantly higher GR expression content than that of the control group(P<0.05). Based on broken method of the relationships between weight gain rate, hepatic riboflavin contents and dietary riboflavin concentrations, it can be concluded that the dietary riboflavin requirement for GIFT tilapia was considered to be 10.1 and 19.7 mg/kg diet respectively. 3. The dietary pyridoxine requirement of GIFT tilapiaThere were 360 GIFT tilapia and divided into 6 groups randomly, every group has three replicates, 20 fish per replicate. GIFT tilapia(initial weight 56.3±1.8 g) were fed purified diets containing six levels(0.3, 2.7, 5.4, 10.1, 20.5 and 39.8 mg/kg diet) of pyridoxine in separate 10 weeks. The experiment was used to determine the dietary riboflavin requirement of GIFT tilapia on the basis of growth parameters and a pyridoxine-dependent biochemical function. The results showed that, with the dietary pyridoxine level increasing, weight gain rate of tilapia first increased linearly then remained nearly unchanged. Fish fed the diets with supplementation of riboflavin showed significantly higher protein content of the whole body and muscle than fish fed the control diet without supplementation of riboflavin(P<0.05). With the dietary pyridoxine increasing, the serum ALP activity, ALB, BUN, TP content increase, while the GLU content had no significant differences among various treatments(P>0.05). Fish fed the control diet with supplementation of pyridoxine showed significantly higher hepatic AST activity, ALT activity and lower TGK content than fish fed diets supplemented without pyridoxine(P < 0.05). Based on broken method of the relationships between weight gain rate and dietary riboflavin concentrations, it can be concluded that the dietary riboflavin requirement for GIFT tilapia was considered to be 9.1 mg/kg diet respectively.