title: Increasing dietary lysine increases final pH and decreases drip loss of broiler breast meat.
abstract: Responses to increased dietary Lys concentrations were evaluated on 1,584 Ross 308 male broilers between 21 and 42 d of age housed according to 2 bird densities. The experimental design was composed of 8 factorial treatments: 2 bird densities (22 or 44 broilers/ 1.7 m(2) pen) x 4 true digestible (TD) Lys levels (0.83, 0.93, 1.03, and 1.13%). There were 6 repetitions per treatment. Birds were weighed individually at d 21 and 42. Feed consumption was recorded per pen. Body weight gain and feed conversion were calculated over the experimental period. Forty-eight broilers per treatment were dissected at 42 d of age. Final pH and drip loss during storage were measured on the pectoralis major. Density adversely affected feed intake (169 +/- 1 and 160 +/- 1 g/d with 22 and 44 birds per pen, respectively, P < 0.05), growth rate (97.4 +/- 0.5 and 91.0 +/- 0.7 g/d, P < 0.05), and feed conversion (1.730 +/- 0.008 and 1.760 +/- 0.006, P < 0.05). Except for feed intake, there was no interaction between the effects of bird density and dietary Lys. An increase in dietary TD Lys from 0.83 to 0.93% resulted in an increased growth rate (from 91.8 +/- 1.6 to 95.5 +/- 0.8 g/d, P < 0.05), improved feed conversion (from 1.783 +/- 0.008 to 1.742 +/- 0.009, P < 0.05), and increased breast meat yield (22.0 +/- 0.1% to 22.7 +/- 0.2%, P < 0.01). Performance and body composition traits were not significantly improved for concentrations of TD Lys higher than 0.93%. However, final breast pH increased from 0.83 up to 1.03% TD Lys in the diet (6.02 +/- 0.01 vs. 5.91 +/- 0.01, P < 0.05), and drip loss correlatively decreased (0.85 +/- 0.03% vs. 1.10 +/- 0.06, P < 0.05). This result opens new way of research for the definition of an amino acid requirement and on metabolic pathways involved in variations of breast muscle pH.
authors.affiliation: Institut National de la Recherche Agronomique, UR83 Recherches Avicoles, F-37380 Nouzilly, France. berri@tours.inra.fr
authors.forename: C
authors.initials: C
authors.lastname: Berri
authors.forename: J
authors.initials: J
authors.lastname: Besnard
authors.forename: C
authors.initials: C
authors.lastname: Relandeau
mesh_terms: D000821:Animal Feed; D000824:Animal Nutritional Physiological Phenomena / Q000502:physiology; D000818:Animals; D001823:Body Composition; D002645:Chickens / Q000254:growth & development / Q000378:metabolism; D004044:Dietary Proteins / Q000008:administration & dosage / Q000378:metabolism*; D004063:Digestion; D004305:Dose-Response Relationship, Drug; D002149:Energy Intake / Q000502:physiology*; D006863:Hydrogen-Ion Concentration; D008239:Lysine / Q000008:administration & dosage / Q000378:metabolism*; D008297:Male; D008460:Meat / Q000032:analysis / Q000592:standards*; D011156:Population Density; D011897:Random Allocation; D015430:Weight Gain
chemical_list: D004044:Dietary Proteins; D008239:Lysine