caa a22 4500 397568827 CHVBK 20180308164835.0 cr unu---uuuuu 161202e199610 xx s 000 0 eng 10.3382/ps.0751253 doi (NATIONALLICENCE)oxford-10.3382/ps.0751253 Digestible Threonine Requirement of Broiler Chickens During the Period Three to Six and Six to Eight Weeks Posthatching [Elektronische Daten] [DOUGLAS M. WEBEL, SERGIO R. FERNANDEZ, CARL M. PARSONS, DAVID H. BAKER] Four experiments were conducted to determine the digestible Thr requirement of commercial broiler chickens (Ross × Hubbard) during the period 3 to 6 and 6 to 8 wk posthatching. Threonine-deficient corn-peanut meal basal diets (3,200 MEn/kg) contained 20% CP and 0.50% Thr for 3- to 6-wk-old birds, and 18.3% CP and 0.50% Thr for 6- to 8-wk-old birds. True digestibility assessment using cecectomized roosters indicated that Thr was 81% digestible in both basal diets. Thus, both diets contained 0.40% digestible Thr. Growth rate and feed efficiency of chicks fed the corn-peanut meal basal diets supplemented with surfeit Thr was equal to that of chicks fed a 20% CP Met-fortified corn-soybean meal diet. Graded doses of Thr produced marked responses (P < 0.05) in weight gain and feed efficiency in birds of both age groups. Maximal feed efficiency was achieved at 0.61% digestible Thr in 3- to 6-wk-old birds and at 0.52% digestible Thr in 6- to 8-wk-old birds. Extrapolating these digestible Thr requirements to total requirements for chicks consuming corn-soybean meal diets (Thr digestibility = 87%) results in estimates of 0.70 and 0.60% for broiler chickens during the growth periods 3 to 6 and 6 to 8 wk posthatching, respectively. These estimates are lower than those of NRC (1994) but are in close agreement with those obtained from ideal protein calculations, i.e., Thr requirements should be 70% of lysine requirements for chicks 3 to 8 wk of age. © 1996 Poultry Science Association, Inc. Metabolism and Nutrition nationallicence broiler chick nationallicence threonine nationallicence amino acid requirement nationallicence WEBEL DOUGLAS M. aut FERNANDEZ SERGIO R. aut PARSONS CARL M. aut BAKER DAVID H. 3To whom correspondence should be addressed at: 290 Animal Sciences Laboratory, 1207 West Gregory Drive, Urbana, IL 61801. aut Poultry Science Oxford University Press 75/10(1996-10), 1253-1257 0032-5791 75:10<1253 1996 75 ps https://doi.org/10.3382/ps.0751253 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.3382/ps.0751253 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- WEBEL DOUGLAS M. aut NATIONALLICENCE 700 1- FERNANDEZ SERGIO R. aut NATIONALLICENCE 700 1- PARSONS CARL M. aut NATIONALLICENCE 700 1- BAKER DAVID H. 3To whom correspondence should be addressed at: 290 Animal Sciences Laboratory, 1207 West Gregory Drive, Urbana, IL 61801 aut NATIONALLICENCE 773 0- Poultry Science Oxford University Press 75/10(1996-10), 1253-1257 0032-5791 75:10<1253 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