Evaluation of In Vitro Apparent Protein Digestibility by Shrimp Using Gut Enzyme Extracts |
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| Authors: | Joe M Fox Addison L Lawrence |
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| Affiliation: | 1. Harte Research Institute for Gulf of Mexico Studies, Texas A&M University—Corpus Christi, 6300 Ocean Drive, Corpus Christi, Texas 78412 USA;2. Texas Agricultural Experiment Station, Shrimp Mariculture Program, Texas A&M University System, 1300 Port Street, Port Aransas, Texas 78373 USA |
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| Abstract: | Knowledge of apparent protein digestibility (APD) is required for optimization of feed formulae for the production of marine penaeid shrimp. The purpose of this study was to evaluate an in vitro method for determining APD in marine penaeid shrimp using gut enzyme extracts. A high correlation (r2 = 0.95) was shown between single‐ingredient APD values for fish meal diets using in vivo methodology and those derived from in vitro testing of ingredients. A second study showed positive correlation (r2 = 0.71) between in vitro APD of selected purified and semipurified ingredients and their reported in vivo APDs. This correlation was much higher for purified ingredients (r2 = 0.93) versus less‐refined ingredients (r2 = 0.24). A third trial compared in vitro APD at three different enzyme extract pH values and showed that for most protein sources, APD was significantly highest (P < 0.05) at pH = 7.0 and lower at pH = 6.1 or 7.9, indicating a neutral pH optimum for this methodology. |
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