碩士 / 國立海洋大學 / 水產養殖學系 / 91 / Three experiments were conducted to investigate the effects of protein levels and protein to energy ratio on the weight gain, survival and body composition of juvenile cobia, Rachycentron canadum.
In the first trial, triplicate groups of cobia (4.6±0.1g initial body weight) were fed isocaloric diets containing five dietary protein levels from 30 to 50% diet with 5% increment for 4 weeks. Fish meal was used as a dietary protein. Cobia fed a diet containing 50% protein had the best weight gain (1585.9%), and there was no significant difference among those fed diets containing 35、40、45 and 50% protein. Food conversion ratio (FCR) and protein efficiency (PER) were 0.8~1.2 and 2.28~2.5. Survival of all treatments was 100%. Based on the percentage weight gain data using second-order polynomial regression analysis, the optimal dietary protein of juvenile cobia was found to be approximately 47.5%. The moisture、ash and crude lipid content of cobia muscle had no significant difference among all treatment, but the crude protein of muscle of cobia increase with increasing dietary protein level.
The dietary protein to energy ratio for cobia was evaluated in experiment 2 and 3. In the second trial, triplicate groups of cobia (5.9±0.5g initial body weight) were fed eight diets containing two protein levels (25 and 35%) and four P/E ratio (100、112.5、125、137.5 mg protein/Kcal). Fish meal was used as protein source and energy contents of diets were adjusted by lipid mixture (cod liver oil: corn oil=2:1) in experiment 2 and 3. Cobia a fed diet containing 35% protein and P/E ratio=100 mg protein/Kcal had the highest percentage weight gain and were no significant difference between those fed diets containing 35% protein and P/E ratio=112.5~125 mg protein/Kcal. Factorial experimental design indicated that cobia fed diets containing 35% dietary protein had the significant higher weight gain than those fed 25% dietary protein and those fed diets containing low P/E ratio (100、112.5 mg protein/Kcal) had the significant higher weight gain than those fed diets containing high P/E ratio (137.5 mg protein/Kcal).
In the third trial, triplicate groups of cobia (5.35±0.13g initial body weight) were fed eight diets containing 25% protein、P/E ratio=100 mg protein/Kcal, 35% protein、P/E ratio=100~137.5 mg protein/Kcal, 45% protein，P/E ratio=112.5~137.5 mg protein/Kcal. Cobia fed diet containing 45% protein and P/E ratio=112.5 mg protein/Kcal had the highest percentage weight gain. Factorial experimental design indicated that cobia fed diets containing 45% dietary protein had the significant higher weight gain than those fed diets containing 35% dietary protein and those fed diets containing low P/E ratio (112.5、125 mg protein/Kcal) had the significant higher weight gain than those fed diets containing high P/E ratio (137.5 mg protein/Kcal). Survivals of all treatments were 100%. In the experiment 2 and 3, cobia fed high protein diets had lower muscle protein content, and muscle lipid content increase with increasing the diet lipid. It is suggested that juvenile cobia require a diet containing 45% protein and a protein to energy ratio between 112.5~125 mg protein/Kcal, when fish meal was used as the protein source.
| Identifer | oai:union.ndltd.org:TW/091NTOU0086030 |
| Date | January 2003 |
| Creators | 沈亮廷 |
| Contributors | 沈士新 |
| Source Sets | National Digital Library of Theses and Dissertations in Taiwan |
| Language | zh-TW |
| Detected Language | English |
| Type | 學位論文 ; thesis |
| Format | 69 |
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