Two experiments were conducted to study the effects of dietary protein quality on the growth of juvenile cobia Rachycentron canadum. Experiment I was to find out the maximum level of steam dried blood meal and spray dried blood meal can be used in the diet for juvenile cobia. Experiment II examined how juvenile cobia utilizes supplemental amino acids. In Experiment I, 9 test diets were evaluated. In the first group, steam dried blood meal was used to partially replace fish meal. The replacement levels were 0, 10, 20, 30 and 40% of the fish meal protein. In the second group, crystalline methionine, which was 0.1 and 0.2% of the diets, was added respectively to 2 diets in which 20 and 40% of the fish meal protein was replaced by blood meal. In the third group, spray dried blood meal was used to replace fish meal protein at 20 and 40% instead of steam dried blood meal. Juvenile cobia with an initial weight of 72g were fed with the test diets for 8 weeks. The results showed that the percent weight gain (PWG), specific growth rate (SGR), feed conversion ratio (FCR), protein efficiency ratio (PER) and net protein utilization ratio (NPU) were significantly reduced (P¡Õ0.05) when the replacement level was increased from 20% to 30%. Spray dried blood meal was more effectively than steam dried blood meal was at high replacement level (40%) than low replacement level (20%). Supplementation of crystalline methionine in the cobia diet had no positive effects. In Experiment II, 8 test diets were studied. The control diet contained only fish meal as the sole protein source. The other seven diets all contained steam dried blood meal which replaced 30% of fish meal protein. In the first group of 3 diets, (1) crystalline methionine, (2) crystalline methionine and crystalline isoleucine, (3) crystalline methionine, crystalline isoleucine and crystalline arginine were added, respectively. Two diets were supplemented with (1) microencapsulated (glycerol monostearate) methionine, (2) microencapsulated methionine and microencapsulated isoleucine. Two diets were supplemented with (1) microcoated (cellulose acetate phthalate) methionine, (2) microcoated methionine and microcoated isoleucine. Juvenile cobia with an initial weight of 33g were fed with the test diets for 8 weeks. The results showed that when the fish meal was partially replaced and amino acids were added, the PWG, SGR, FCR, PER and NPU of the cobia were significantly reduced compared to the control group (P¡Õ0.05). In conclusion, steam dried blood meal could effectively replace fish meal up to 20% of the fish meal protein, which was 6.2% of the diet. Spray dried blood meal showed better effects on the growth of fish than steam dried blood meal when given at high level. The two types of blood meal were no difference when the replacement levels were low. Juvenile cobia were not able to effectively use the different types of amino acids evaluated in the experiments.
| Identifer | oai:union.ndltd.org:NSYSU/oai:NSYSU:etd-0201104-142614 |
| Date | 01 February 2004 |
| Creators | Lin, Kuo-Wei |
| Contributors | Houng-Yung Chen, Chen-Huei Huang, Cheng-Fang Chang, Shi-Yen Shiau |
| Publisher | NSYSU |
| Source Sets | NSYSU Electronic Thesis and Dissertation Archive |
| Language | Cholon |
| Detected Language | English |
| Type | text |
| Format | application/pdf |
| Source | http://etd.lib.nsysu.edu.tw/ETD-db/ETD-search/view_etd?URN=etd-0201104-142614 |
| Rights | unrestricted, Copyright information available at source archive |
Page generated in 0.0013 seconds