Dietary guanidineacetic acid supplementation ameliorated meat quality and regulated muscle metabolism of broilers subjected to pre-slaughter transport stress by metabolomics analysis

Pre-slaughter transport stress could induce multiple comprehensive variations in physiological and metabolic parameters of broilers. However, the entire metabolomics of pre-slaughter transport stress and supplementation of exogenous energy regulatory substances on broilers is still poorly understood. The metabolome characteristics of broilers subjected to 3 h pre-slaughter transport stress combined with 1,200 mg/kg guanidinoacetic acid (GAA1,200) supplementation were analyzed using gas chromatography-mass spectrometry (GC−MS) in this study. The results showed that, compared to the control group (no transport), 3 h pre-slaughter transport stress (T3h) decreased creatine (Cr), phosphocreatine (PCr) and adenosine triphosphate (ATP), and increased adenosine diphosphate (ADP), adenosine monophosphate (AMP) and the ratio of AMP to ATP in pectoralis muscle (PM) of broilers by high performance liquid chromatography (HPLC) analysis. However, GAA1,200 supplementation reversed the negative effects induced by 3 h pre-slaughter transport stress. Besides, GAA1,200 supplementation elevated mRNA expression of creatine transporter in PM. Our metabolomics approaches demonstrated that 38 and 48 significant metabolites were separately identified between the control group and T3h group, and T3h group and 3 h pre-slaughter transport stress combined with GAA1,200 supplementation group using the standard of variable importance in the projection values >1 and P < 0.05. Among these, the metabolites involved in amino acid metabolism (alanine, glycine, serine, threonine, cysteine , methionine, phenylalanine, tyrosine, and tryptophan), oxidative stress (3-methylhistidine, 1-methylhistidine and glutathione), non-protein amino acid (citrulline) metabolism, and energy metabolism (Cr, PCr, sarcosine, and glycocyamine) were confirmed through pathway enrichment analysis, which could be chosen as suitable candidate targets for further analysis of the effects of exogenous energy substances on broilers subjected to transport stress.