Effect of dietary arginine to lysine ratios on productive performance, meat quality, plasma and muscle metabolomics profile in fast-growing broiler chickens

Abstract

Background: Due to the important functions of arginine in poultry, it should be questioned whether the currently adopted dietary Arg:Lys ratios are sufficient to meet the modern broiler requirement in arginine. The present study aimed, therefore, to evaluate the effects of the dietary supplementation of L-arginine in a commercial broiler diet on productive performance, breast meat quality attributes, incidence and severity of breast muscle myopathies and foot pad dermatitis (FPD), and plasma and muscle metabolomics profile in fast-growing broilers.

Results: A total of 1,170 1-day-old Ross 308 male chicks was divided into two experimental groups of 9 replicates each fed either a commercial basal diet (CON, digestible Arg:Lys ratio of 1.05, 1.05, 1.06 and 1.07 in each feeding phase, respectively) or the same basal diet supplemented on-top with crystalline L-arginine (ARG, digestible Arg:Lys ratio of 1.15, 1.15, 1.16 and 1.17, respectively). Productive parameters were determined at the end of each feeding phase (12, 22, 33, 43 d). At slaughter (43 d), incidence and severity of FPD and breast myopathies were assessed, while plasma and breast muscle samples were collected and analyzed by proton nuclear magnetic resonance-spectroscopy. The dietary supplementation of arginine significantly reduced cumulative feed conversion ratio compared to the control diet at 12 d (1.352 vs. 1.401, P < 0.05), 22 d (1.398 vs. 1.420; P < 0.01) and 33 d (1.494 vs. 1.524; P < 0.05), and also tended to improve it in the overall period of trial (1.646 vs. 1.675; P = 0.09). Body weight was significantly increased in ARG compared to CON group at 33 d (1,884 vs. 1,829 g; P < 0.05). No significant effect was observed on meat quality attributes, breast myopathies and FPD occurrence. ARG birds showed significantly higher plasma concentration of arginine and leucine, and lower of acetoacetate, glutamate, adenosine and proline. Arginine and acetate concentrations were higher, whereas acetone and inosine levels were lower in the breast of ARG birds (P < 0.05).

Conclusions: Taken together, these data showed that increased digestible Arg:Lys ratio had positive effects on feed efficiency in broiler chickens probably via modulation of metabolites that play key roles in energy and protein metabolism.

Keywords: 1H–NMR spectroscopy; Arginine; Broiler chicken; Meat quality; Metabolomics; Nuclear magnetic resonance; Nutrition; Productive performance.

Fig. 1

Incidence and severity of foot pad dermatitis in CON and ARG broiler chickens. CON, n = 574: digestible Arg:Lys = 1.05, 1.05,  1.06 and 1.07 in starter, grower I, grower II and finisher feeding phase, respectively. ARG, n = 569: digestible Arg:Lys = 1.15, 1.15, 1.16 and 1.17, respectively. [0 = no lesions; 1 = mild lesions (< 0.8 cm); 2 = severe lesions (> 0.8 cm)]

Fig. 2

Robust Principal Component Analysis on plasma metabolites showing differential expression between CON and ARG groups. CON, n = 9; digestible Arg:Lys = 1.05, 1.05, 1.06 and 1.07 in starter, grower I, grower II and finisher feeding phase, respectively. ARG, n = 9; digestible Arg:Lys = 1.15, 1.15, 1.16 and 1.17, respectively. a In the scoreplot, samples from chickens fed different diets are represented with squares and circles respectively. The wide, empty circles represent the median of the samples at the various time-points. b Boxplot summarizing the position of the subjects along PC 1. c Loadingplot reports the correlation between the concentration of each substance and its importance over PC 1. Highly significant correlations (P < 0.05) are highlighted with gray bars

Fig. 3

Robust Principal Component Analysis on breast metabolites showing differential expression between CON and ARG groups. CON, n = 9; digestible Arg:Lys = 1.05, 1.05, 1.06 and 1.07 in starter, grower I, grower II and finisher feeding phase, respectively. ARG, n = 9; digestible Arg:Lys = 1.15, 1.15, 1.16 and 1.17, respectively. a In the scoreplot, samples from chickens fed different diets are represented with squares and circles respectively. The wide, empty circles represent the median of the samples at the various time-points. b Boxplot summarizing the position of the subjects along PC 1. c Loadingplot reports the correlation between the concentration of each substance and its importance over PC 1. Highly significant correlations (P < 0.05) are highlighted with gray bars

Fig. 4

Hypothetical molecular responses to the dietary supplementation of L-arginine in broiler chicken