|
|
||||||||
Articles |
Department of Poultry Science, Mississippi State University, Mississippi State, MS 39759-9665, USA. mkidd@poultry.msstate.edu
The Thr needs in 3 commercial broiler strains (A, multipurpose; B, high yield; C, high yield) known to differ in terms of feed intake, growth rate, and breast yield were evaluated. Birds were randomized across 96 floor pens (12 birds/pen), received a common diet from d 1 to 20, and were fed graduations of Thr (0.52 to 0.87% total Thr in 0.07% increments) from d 21 to 42. Treatments (3 x 6 factorial) were replicated 5 or 6 times. The corn, soybean meal, and peanut meal test diet contained 0.43 and 0.96% digestible Thr and Lys, respectively. An additional group of strain C birds (6 pens) was maintained on a corn-soybean meal diet containing surfeit Thr (0.73% of diet). Birds fed the corn and soybean meal diet performed similarly (P < or = 0.05) to birds fed peanut meal diets. A feed conversion interaction (P < or = 0.05) occurred indicating that strain C was more sensitive to Thr deficiency than strains A and B. The abdominal fat interaction (P < or = 0.05) indicated that strain A had more relative abdominal fat than strains B and C. All strains differed (P < or = 0.05) in terms of BW gain (A, 78.2; B, 75.1; C, 72.9 g/d). Strain C had the lowest (P < or = 0.05) feed intake, which resulted in the lowest (P < 0.05) Thr intake, but it had the highest (P < or = 0.05) breast meat yield. Most parameters tested yielded quadratic (P < or = 0.05) models whereby Thr estimates could be predicted. Namely, BW gain and breast meat yield resulted in total Thr estimates (95% of maximum response) of 0.74 and 0.71%, respectively, which are in close agreement with the 1994 NRC (0.74%). The plasma Thr sigmoid response verified the former estimates. Analysis of strain intercepts and slopes as affected by Thr differed (P < or = 0.05) in terms of feed intake but not BW gain or breast meat yield. The 21 to 42 d Thr need across strains was estimated as 0.74% total or 0.65% digestible. Because dietary Lys was not in excess of the bird's needs, the former digestibility estimate equated to a Thr/Lys of 0.68.
This article has been cited by other articles:
![]() |
A. Corzo, W. A. Dozier III, R. E. Loar II, M. T. Kidd, and P. B. Tillman Assessing the threonine-to-lysine ratio of female broilers from 14 to 28 days of age J. Appl. Poult. Res., January 1, 2009; 18(2): 237 - 243. [Abstract] [Full Text] [PDF] |
||||
![]() |
A. C. Fanatico, P. B. Pillai, P. Y. Hester, C. Falcone, J. A. Mench, C. M. Owens, and J. L. Emmert Performance, Livability, and Carcass Yield of Slow- and Fast-Growing Chicken Genotypes Fed Low-Nutrient or Standard Diets and Raised Indoors or with Outdoor Access Poult. Sci., June 1, 2008; 87(6): 1012 - 1021. [Abstract] [Full Text] [PDF] |
||||
![]() |
Samadi and F. Liebert Threonine Requirement of Slow-Growing Male Chickens Depends on Age and Dietary Efficiency of Threonine Utilization Poult. Sci., June 1, 2007; 86(6): 1140 - 1148. [Abstract] [Full Text] [PDF] |
||||
![]() |
A. Corzo, M. T. Kidd, W. A. Dozier III, G. T. Pharr, and E. A. Koutsos Dietary Threonine Needs for Growth and Immunity of Broilers Raised Under Different Litter Conditions J. Appl. Poult. Res., January 1, 2007; 16(4): 574 - 582. [Abstract] [Full Text] [PDF] |
||||
![]() |
Samadi and F. Liebert Modeling of threonine requirement in fast-growing chickens, depending on age, sex, protein deposition, and dietary threonine efficiency. Poult. Sci., November 1, 2006; 85(11): 1961 - 1968. [Abstract] [Full Text] [PDF] |
||||
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |