Effect of protein concentrations in the diet on productive performance, carcass characteristics, and meat chemical composition of broiler chickens in the dry subtropics

Authors: INFANTE-RODRIGUEZ, FIDEL - University Of Tamaulipas; DOMÍNGUEZ MUÑOZ, MIGUEL - University Of Tamaulipas; MONTAÑO-GÓMEZ, MARTÍN - Universidad Autonoma De Baja California; Hume, Michael; Anderson, Robin; MANRÍQUEZ-NUÑEZ, OLGA - Universidad Autonoma De Baja California; LÓPEZ-ACEVEDO, EDGAR - University Of Tamaulipas; BAUTISTA-MARTINEZ, YURIDIA - University Of Tamaulipas; SALINAS-CHAVIRA, JAIME - University Of Tamaulipas

Submitted to: Nova Scientia
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/5/2020
Publication Date: 11/10/2020
Citation: Infante-Rodriguez, F.M., Domínguez Muñoz, M.A., Montaño-Gómez, M.F., Hume, M.E., Anderson, R.C., Manríquez-Nuñez, O.M., López-Acevedo, E.A., Bautista-Martinez, Y., Salinas-Chavira, J. 2020. Effect of protein concentrations in the diet on productive performance, carcass characteristics, and meat chemical composition of broiler chickens in the dry subtropics. Nova Scientia. 12(25). https://doi.org/10.21640/ns.v12i25.2585.
DOI: https://doi.org/10.21640/ns.v12i25.2585

Interpretive Summary: Current broiler chicken diets tend to increase protein levels to support improved broiler performance. However, an increase in dietary protein levels does not always result in an increase in broiler productive efficiency. The objective of this study was to evaluate the effect of increasing levels of dietary protein on production performance, carcass characteristics, and chemical composition of breast and thigh meat in broiler chickens raised in the dry subtropics of northeastern Mexico. The study was divided in two phases, starter (1-21 days) and finisher (22-42 days). Treatment diets (T) for starter and finisher phases had percentage protein concentrations of 21.0 and 18.1 (T1), 21.4 and 18.5 (T2), 21.8 and 18.9 (T3), and 22.2 and 19.3 (T4), respectively. Protein concentrations had no effect on weight gain, while feed intake was greater in T1 than in T2 and T3. Feed conversion to body weight was better in T2 and T4 than in T1. There was no influence of treatment on carcass weight or carcass cut pieces. These results indicated that in the dry subtropics area of northeastern Mexico, increases in diet protein above the level of T2 may not improve broiler chicken productive performance, carcass characteristics, or meat composition. These results are of interest to researchers and growers seeking diet supplementation to improve broiler meat values.

Technical Abstract: Current diets of broiler chickens tend to increase protein levels to support the high productive parameters that are obtained after genetic, management, and sanitary improvements, among others. However, an increase in dietary protein levels does not always accompany an increase in broiler productive efficiency due to multiple factors involved in the production system. The objective of this study was to evaluate the effect of increasing levels of dietary crude protein (CP) on production performance, carcass characteristics, and chemical composition of breast and thigh meat in broiler chickens raised in the dry subtropics of northeastern Mexico. The study used 200, 1-day-old male Ross broiler chicks. In a completely randomized design, birds were allocated to the four treatments with five replicates (floor pens) of ten birds each. The trial was divided in two phases (starter and finisher) of 21 days each (42 days total). Treatment diets (T) for starter and finisher phases had crude protein concentrations (CP; %) of 21 and 18.1 (T1), 21.4 and 18.5 (T2), 21.8 and 18.9 (T3), and 22.2 and 19.3 (T4), respectively. Within each feeding phase, the four treatment diets were formulated to similar levels of apparent metabolizable energy. Protein concentrations had no effect (P > 0.05) on weight gain, while feed intake was greater in T1 (P < 0.05) than in T2 and T3. Feed conversion was better in T2 and T4 (P < 0.05) than in T1. There was no influence of treatment on carcass weight or carcass cuts (P > 0.05). Carcass yield was greater in T1 than in T3 (P < 0.05). Breast and thigh dry matter and ether extracts were similar (P > 0.05) between treatments. Breast crude protein was greater (P < 0.05) in T2 than in T3. The lowest (P < 0.05) CP concentration in thigh meat was in T3. These results indicate that in the dry subtropics area of northeastern Mexico, increases in CP above the level of T2 may not improve broiler chicken productive performance, carcass characteristics, or meat chemical composition.