Effects Of Cysteamine On Digestive Enzymes And Endocritic Regulation In Tilalpia

During this study, the methods of radioimmunoassay, enzymatic reaction, immunohistochemistry were used to evaluate the content of hormones in the blood, the activity of digestive enzyme, the changes of the number of endocrine cells in the digestive tract. The objective is to investigate the impact of the tilapia feed added with cysteamine to the growth performance, digestive enzyme and endocrine regulation of tilapia. Five groups were set: the control group (0 mg / kg), group 150 (150 mg / kg), group 300 (300 mg / kg), group 600 (600 mg / kg) and group 900 (900 mg / kg).The results are as follows:1,On the 45th day, the weight increase rate of the cystramine adding groups were higher than the control group. Among them, the increase rate of group 300 is the highest, 34.0% higher than that of the control group, reaching extremely significant the difference level (P<0.01).2,On the 14th day, the contents of SS and TSH in group 900 were the lowest than those in other groups while the contents of IGF-I, gastrin and T4 in group 900 were the highest. The content of T3 in group 300 was the highest. Then on the 28th day, the content of SS in group 900 was the lowest while the content of IGF-I in group 900 was the highest. The content of TSH in group 300 was the lowest, while the contents of Gas, T3 and T4 in group 300 were the highest. And then on the 42nd day, the content of SS in group 900 was the lowest, while the contents of gastrin,T3 and T4 in group 900 were the highest and lowest TSH in group 300, highest IGF-I in group 600. The differences of all the above indexes between the experimental groups and the control group were significant at different periods (P<0.05).3,On the 14th day, 28th day and 42th day, the activity of intestine amylase in group 300 was the highest, the activity of trpsin in group 600 was the highest, but the differences of the activity of lipase between the experimental groups and the control group were not significantly (P>0.05 ) . The activity of amylase in the hepatopancreas in group 900 was the highest on the 14th day and 28th day, and highest in group 600 on the 42th day. The activity of trypsin in group 600 was higheset on the 14th day, but there's no significant differences between experimental groups and the control group on the 28th day and the 42th day (P>0.05). The activity of lipase in group 300 is the highest during various stages. In different stage, the activity of amylase in intestine and the activity of amylase and lipase in hepatopancreas between experimental groups and the control group were significantly different (P<0.05). On the 28th day, the differences of the activity of trypsin in the intestine between experimental groups and the control group was significant and it's the same to the trypsin on the 14th day (P <0.05).4,On the 42th day, at the bottom of the stomach, the number of the SS-positive cells in group 300 was the lowest, the number of the 5-HT-positive cells in group 900 was the highest and the number of the Gas-positive cells in group 600 was the highest. In stomachus pyloricus, the number of the SS-positive cells in group 900 was the lowest, most 5-HT-positive cells in group 300 and most Gas-positive cells in group 300. The diiferences of all the above indexes between the experimental groups and the control group were significant (P <0.05).The experiment indicates that the addition of appropriate cysteamine could lead to the improvement of the growth of tilapia, the decrease of the content of SS in the blood, and meanwhile arise the increase the content of IGF-I, Gas, T3 and T4, the decrease of TSH, and bring the increase in the activities of amylase, trypsin and lipase in intestine and hepatopancreas, the fall in the number of the SS-positive cells, and the increase in the number of 5-HT and Gas-positive cells in stomachus fundus and stomachus pyloricus.