Digestive enzymes of penaeid shrimp : a descriptive and quantitative examination of the relationships of enzyme activity with growth, age and diet.
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| Other Authors: | , |
| Format: | Thesis Book |
| Language: | English |
| Published: |
1984.
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| Subjects: | |
| Online Access: | Link to ProQuest Copy |
| Abstract: | The relationships between protein level, protein source, growth and digestive enzyme activities were investigated for three species of penaeid shrimp, Penaeus aztecus, Penaeus setiferus and Penaeus vannamei. The shrimp were fed ad libitum for 30 days with six isocaloric diets and a starved control group was included in each experiment. The diets consisted of two series having different animal to plant protein ratios, 2:1 and 1:1, with each series having protein levels of 22%, 30% and 38%. The following activities were detected in extracts prepared from the digestive tracts of the shrimp; trypsin, carboxypeptidase A, carboxypeptidase B, general and acid protease, amylase, chitinase, esterase and lipase. The extracts lacked chymotryptic and peptic activities. The three species of shrimp exhibited significant differences in their enzymatic responses to dietary variables. P. aztecus displayed increased general protease activities as the protein level of the diet increased but the carbohydrase and lipolytic enzyme activities remained unchanged. P. setiferus exhibited greater general protease, carbohydrase and lipase activities as the protein level of the diet decreased. P. vannamei exhibited no significant changes in digestive enzyme activity with protein level. These differences suggest that enzyme secretions in P. vannamei, a tropical species, may be less able to adapt to dietary changes than those of the subtropical species, P. aztecus and P. setiferus. The differences between the digestive enzyme profiles of the latter species may be a result of differences in dietary regimen. Digestive enzyme activities also varied with size (P. vannamei). Large shrimp (> 10 g) exhibited few changes in enzyme activities that could be related to diet while smaller shrimp (< 10 g) exhibited higher activities on the 2:1 animal to plant protein ratio diets than 1:1 ratio diets. Therefore, protein quality exerts an influence on the digestive enzyme activities of small P. vannamei which disappears in larger shrimp. These comparative differences in the hydrolytic abilities of various sizes and species of penaeid shrimp should be considered in the design of commercial shrimp diets. |
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| Item Description: | Typescript (photocopy). Vita. "Major subject: Nutrition." |
| Physical Description: | x, 148 leaves : illustrations ; 29 cm |
| Bibliography: | Includes bibliographical references (leaves 135-147). |