Effect of arginine supplementation on liver and pectoral muscle: Tissue-specific lipid metabolism in broilers

Abstract

Abdominal fat (AF) and intramuscular fat (IMF) are key carcass traits in broilers but managing both is challenging due to their contrasting effects. Arginine (Arg) supplementation has potential effect in lipid metabolism, however its tissue specific effect remains poorly understood. The objective of this study was to investigate the tissue specific effect of Arg supplementation on growth performance and fat metabolism in both liver and pectoral muscle in broilers. A total of 480 Arbor Acre chicks were randomly assigned to four groups: Control (0 g/kg), Arg (1.8 g/kg), 5 × Arg (9 g/kg) and 10 × Arg (18 g/kg), with 12 replicates of 10 birds each. Overall, high Arg supplementation (5 ×, 10 ×) significantly impaired growth performance, reducing average daily gain and feed intake, accompanied by elevated serum AST and IFN-γ levels (P < 0.05). Liver transcriptomics analysis revealed that 10 × Arg significantly enriched PPAR signaling pathway, promoting fatty acid oxidation while suppressing lipogenic genes. Conversely, in pectoral muscle, high Arg (10 ×) promoted intramuscular fat deposition which was associated with downregulation of PPAR-α (P < 0.05) and increased expression of key lipogenic genes involved in de novo lipogenesis (SREBP-1c, FAS, ACC and SCD). Moreover, Arg supplementation modulated drug metabolism genes in liver, including EPX and RRM2, suggesting potential impacts on detoxification pathways. These findings underscore the importance of precise Arg dosing to optimize broiler growth, immune function, and carcass quality by targeting its tissue specific metabolic effect.

Keywords: Abdominal fat; Arginine; Broilers; Intramuscular fat; Lipogenic genes.

Fig. 1

Effect of Arginine supplementation on significant slaughter induces (abdominal fat pad, leg muscle and pectoral muscle) and serum indices (aspartate amino transferase (AST), Interferon gamma (IFN-γ), and Urea). Different values of lowercase letters (a, b) indicate significant differences (P < 0.05). Each mean represents 12 birds per treatment.

Fig. 2

Liver trasncriptomics (n = 8): Principle component analysis (A), Upset diagram (B), Differential statistics of genes (C) KEGG annotation comparative analysis of Arg vs Contorl, 5 × Arg vs Control, 10 × Arginine vs Control (D).

Fig. 3

Liver transcriptomics showing KEGG enrichment analysis of Arg vs Contorl, 5 × Arg vs Control, 10 × Arginine vs Control (A,B,C respectively). N = 8.

Fig. 4

Liver transcriptomics showing correlation heat map of target gene i.e. Drug metabollism, PPAR Signaling, Lipid metabolism between different dietary treatments (mean of TPM value of 8 replicates).

Fig. 5

A) Relative gene expression of *PPAR-signaling pathways genes, **drug Metabolism genes and lipid Metabolism genes (n = 8) i.e. retinol binding protein 7 (RBP7), acyl-CoA synthetase long-chain family member 6 (ACSL6), cytochrome P450 family 8 subfamily B member 1 (CYP8B1), cytochrome P450 family 7 subfamily A member 1 (CYP7A1), lipase G (LIPG), matrix metallopeptidase 1 (MMP1), perilipin 1 (PILIN1), aquaporin 7 (AQP7), peroxisome proliferator factor alpha (PPAR-a), fatty acid synthase (FAS), malic enzyme-1 (ME-1), stearoyl Co-A desaturase-1 (SCD-1), acetyl Co-A carboxylase (ACC), sterol regulatory element binding protein-1c (SREBP-1c), patatin like phospholipase domain-containing 3 (PNPLA3), eosinophil peroxidase (EPX), ribonucleotide reductase regulatory subunit M2 (RRM2). B) Western blot analysis of PPAR-α and ME-1 genes. Means with different superscript differ significantly (P<0.05).

Fig. 6

Relative gene expression of lipid metabolism genes in pectoral muscle (n = 8). Patatin like phospholipase domain-containing 3 (PNPLA3), fatty acid synthase (FAS), malic enzyme-1 (ME-1), acetyl Co-A carboxylase (ACC), sterol regulatory element binding protein-1c (SREBP-1c), peroxisome proliferator factor alpha (PPAR-a) and stearoyl Co-A desaturase-1 (SCD-1). Means with different superscript differ significantly (P<0.05).