caa a22 4500 397567707 CHVBK 20180308164832.0 cr unu---uuuuu 161202e199602 xx s 000 0 eng 10.3382/ps.0750216 doi (NATIONALLICENCE)oxford-10.3382/ps.0750216 Bioavailability of the Digestible Lysine and Valine in Cottonseed and Soybean Meals for Chicks [Elektronische Daten] [S. R. FERNANDEZ, C. M. PARSONS] Previous research showed that formulation of chick diets containing cottonseed meal (CSM) using true digestible amino acid (AA) values was superior to formulation based on total AA; however, optimum growth performance could not be obtained from high CSM diets even when formulated on a digestible AA basis. Therefore, two experiments were conducted to determine whether the digestible AA in CSM were totally bioavailable or utilizable for protein synthesis. Soybean meal (SBM) was also evaluated for comparison. True digestibility of Lys and Val in CSM and SBM were determined using the precision-fed cecectomized rooster assay. Bioavailability was then assessed by chick growth assay using purified crystalline AA diets deficient in Lys or Val that were supplemented with varying levels of the test AA, CSM, SBM, or AA mixtures simulating the digestible AA composition of CSM and SBM. Multiple regression slope-ratio methodology indicated that bioavailability of the digestible Lys in CSM and the digestible Lys and Val in SBM did not differ (P > 0.05) from 100% for most response parameters. Bioavailability of the digestible Val in CSM ranged from 78 to 96% depending on response parameter. Bioavailabilities of crystalline Lys and Val in the AA mixtures simulating CSM and SBM were generally lower than the bioavailabilities of the digestible Lys and Val in CSM and SBM. The results of this study indicated that the digestible Lys and Val in SBM and CSM as measured by the precision-fed cecectomized rooster assay are totally or almost totally bioavailable for protein synthesis. © 1996 Poultry Science Association, Inc. Metabolism and Nutrition nationallicence chick nationallicence soybean meal nationallicence cottonseed meal nationallicence amino acid digestibility nationallicence amino acid bioavailability nationallicence FERNANDEZ S. R. aut PARSONS C. M. 1To whom correspondence should be addressed: 284 Animal Sciences Laboratory, 1207 W. Gregory Drive, Urbana, IL 61801. aut Poultry Science Oxford University Press 75/2(1996-02), 216-223 0032-5791 75:2<216 1996 75 ps https://doi.org/10.3382/ps.0750216 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.3382/ps.0750216 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- FERNANDEZ S. R. aut NATIONALLICENCE 700 1- PARSONS C. M. 1To whom correspondence should be addressed: 284 Animal Sciences Laboratory, 1207 W. Gregory Drive, Urbana, IL 61801 aut NATIONALLICENCE 773 0- Poultry Science Oxford University Press 75/2(1996-02), 216-223 0032-5791 75:2<216 1996 75 ps Metadata rights reserved CC BY-NC-4.0 http://creativecommons.org/licenses/by-nc/4.0 nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-oxford