碩士 / 國立高雄海洋科技大學 / 水產食品科學研究所 / 102 / The aim of this study was to investigate the effect of different dietary proteins on the growth and postprandial changes in free amino acids in the blood of tilapia. The growth performance and free amino acids analyses were performed in the first, fourth and eighth week of the growth trial respectively. In the growth trial, three isonitrogenous and isocaloric experimental diets containing extracted soybean protein ( ESP ), defatted fish protein ( DFP ) and casein (CP) were fed to triplicate group for 8 weeks.
In the first week, there was no significant difference in feed intake among tilapia fed three different diets (p > 0.05). The final weight was significantly higher in tilapia fed the CP diet (p < 0.05), there were no significant difference between tilapia fed the DFP diet and tilapia fed the ESP diet (p > 0.05). The weight gain was highest in tilapia fed the CP diet, followed by tilapia fed the DFP diet and lowest in tilapia fed the ESP diet (p < 0.05). The specific growth rate, feed efficiency and protein efficiency were highest in tilapia fed the CP diet, followed by tilapia fed the DFP diet and lowest in tilapia fed the ESP diet (p < 0.05). The feed conversion ratio was significantly lower in tilapia fed the CP diet (p < 0.05), there were no significant difference between tilapia fed the DFP diet and tilapia fed the ESP diet (p > 0.05). After 1 week of feeding, the results showed that the diet for better growth of tilapia is CP diet.
In the fourth week, the final weight, weight gain and specific growth rate were significantly higher in tilapia fed the CP diet (p < 0.05), there were no significant difference between tilapia fed the DFP diet and tilapia fed the ESP diet (p > 0.05). The feed intake was significantly lower in tilapia fed ESP diet (p < 0.05), there were no significant difference between tilapia fed the CP diet and tilapia fed the DFP diet (p > 0.05). The feed efficiency and protein efficiency were significantly lower in tilapia fed the DFP diet (p < 0.05), there were no significant difference between tilapia fed the CP diet and tilapia fed the ESP diet (p > 0.05). The feed conversion ratio was significantly lower in tilapia fed the CP diet (p < 0.05), there were no significant difference between tilapia fed the DFP diet and tilapia fed the ESP diet (p > 0.05). After 4 week of feeding, the results showed that the diet for better growth of tilapia is also CP diet.
In the eighth week, there was no significant difference in feed intake among tilapia fed three different diets (p > 0.05).The final weight, weight gain, specific growth rate and protein efficiency were significantly lower in tilapia fed ESP diet (p < 0.05), there were no significant difference between tilapia fed the CP diet and tilapia fed the DFP diet (p > 0.05). The feed efficiency was significantly higher in tilapia fed the CP diet (p < 0.05) , there were no significant difference between tilapia fed ESP diet and tilapia fed the DFP diet. The feed conversion ratio was significantly higher in tilapia fed the ESP diet (p < 0.05), there were no significant difference between tilapia fed the CP diet and tilapia fed the DFP diet (p > 0.05). After 8 week of feeding, After 8 week of feeding, the results showed that the diet for better growth of tilapia are CP diet and DFP diet. Whereas, the growth of tilapia was significantly lower (p < 0.05) after feeding ESP diet, its final weight was only 0.65 times or 0.63 times of feeding DFP diet or CP diet respectively.
In the study of postprandial changes in free amino acids in the blood
of tilapia were performed in 3 stages, in the first, fourth and eighth week of the trial. In each stage, all fishes of three groups of tilapia were starved for 48 hours, and then 6 fishes in each group (2 fishes per tank) were taken as zero time samples. The remaining fishes were fed the three groups of diets and then 6 fishes each group were taken at 2, 4, 8, 16 and 24 hours after feeding. The blood samples were withdrawn individually from the caudal peduncle of all sample fish. The free amino acid concentration in the blood was analyzed by using the HPLC system. No matter what stage of the trial, based on the results of postprandial changes of free amino acid absorbed in the blood, it was found that the total free amino acids (TFAA) reached peak level at 4 hours after feeding CP or DFP diet, whereas TFAA reached peak level at 8 hours after feeding ESP diet. And, the total free essential amino acids (TFEAA) and total free non-essential amino acids (TFNEAA) were also following the same tendency of the TFAA. However, it was not consistent in the rates of absorption of individual essential amino acids after feeding ESP diet, their peak levels were distributed widely at a long period of 2-8 hours. Therefore, the slow absorption rate of TFAA and differences in rates of absorption of individual essential amino acids were considered to be the cause of inferior growth and feed performance of tilapia after feeding ESP diet.
Moreover, TFNEAA contents in the blood of tilapia which fed ESP diets was significantly lower than fed the CP diets and the DFP diets. Especially, the proline and alaline, the main components of collagen, were significantly lower in the blood of the the tilapia after feeding ESP diets than tilapia after feeding CP diets or DFP diets. Thus, the lower proline and alaline content after feeding was considered to be influence the syntheses of collagen and growth of tilapia. further experimentation is necessary to explain fully this observation.
| Identifer | oai:union.ndltd.org:TW/102NKIM0084035 |
| Date | January 2014 |
| Creators | Hsu,fukai, 許富凱 |
| Contributors | Lian,juanglin, 連壯林 |
| Source Sets | National Digital Library of Theses and Dissertations in Taiwan |
| Language | zh-TW |
| Detected Language | English |
| Type | 學位論文 ; thesis |
| Format | 175 |
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