Effects of dietary protein and energy manipulations on growth and aspects of nitrogen metabolism of red drum, Sciaenops ocellatus /
influencing growth and body composition of fish. These dietary factors also may affect nitrogenous waste production of fish which has become an increasing concern in aquaculture. Therefore, six separate experiments were conducted to determine protein and energy requirements of red drum as well as ev...
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| Format: | Thesis Book |
| Language: | English |
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[Place of publication not identified] :
[publisher not identified] ;
1998.
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| Subjects: | |
| Online Access: | http://proxy.library.tamu.edu/login?url=http://proquest.umi.com/pqdweb?did=732838501&sid=1&Fmt=2&clientId=2945&RQT=309&VName=PQD |
| Summary: | influencing growth and body composition of fish. These dietary factors also may affect nitrogenous waste production of fish which has become an increasing concern in aquaculture. Therefore, six separate experiments were conducted to determine protein and energy requirements of red drum as well as evaluate various manipulations of dietary protein and energy in terms of weight gain, body composition and nitrogenous waste production. Based on changes in weight and whole-body protein and energy, metabolic protein requirements of juvenile red drum for maintenance and maximals gain ranged l from 0.5 to 2.5 g digestible protein (DP)/(kg BW'day) and 20 to 25 g DP/(kg BW.day), respectively, while energy requirements were 14 to 23 kcal digestible energy (DE)/(kg BW'day) and 185 to 235 kcal DE/(kg BW'day), respectively. These estimates will allow for more precise formulation of diets and feeding strategies to meet the requirements of red drum for specific purposes. Red drum in other experiments received no significant growth benefit from higher dietary energy levels (3.6 vs 4.4 kcal/g) but did deposit more fat in the peritoneal cavity and liver. Ammonia production was higher with increasing dietary protein content (35 to 45% of diet), and within each protein level, ammonia production generally decreased with higher energy levels. Within an energy level, increasing the percentage of dextrin, relative to lipid, resulted in lower ammonia production. Plasma glucose was elevated in fish fed diets with 20% dextrin but plasma glucose level was very similar between fish fed diets with 0% and 8% dextrin. Gluconeogenesis from amino acids likely maintained circulating glucose levels and likely contributed to the significant elevation in ammonia production by fish fed the diets without dextrin. Activities of hepatic glutamate dehydrogenate, glutaminase, and glutamine synthetase responded in such ways as to support the beneficial effect of dextrin in reducing ammonia production and increasing growth. Based on this study, manipulations of dietary protein and energy levels, as well as feeding rates, were identified which may reduce nitrogenous waste production while maintaining acceptable growth and body composition of red drum. |
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| Item Description: | Vita. "Major Subject: Nutrition". |
| Physical Description: | xiii, 135 leaves : illustrations ; 28 cm. Issued also on microfiche from University Microfilm Inc. |
| Bibliography: | Includes bibliographical references: pages 116-133. |