Research advances in intramuscular fat deposition and chicken meat quality: genetics and nutrition

Abstract

Chicken meat quality directly influences consumer acceptability and is crucial for the economic success of the poultry industry. Genetics and nutrition are key determinants of the meat quality traits in broilers. This review summarizes the research advances in this field, with a focus on the genetic and nutritional foundations that regulate intramuscular fat (IMF) deposition and meat quality in chickens over the past decade. The effects of embryonic nutrition, both maternal nutrition and in ovo feeding (IOF), on skeletal muscle development, the IMF content, and meat quality traits in broilers are also discussed. In genetics, single-cell RNA sequencing revealed that de novo lipogenesis predominantly occurs in myocytes, which is key to the formation of IMF in chicken muscle tissue. Fatty acid synthase (FASN) is the key enzyme involved in this process. This discovery has reshaped the traditional understanding of intramuscular lipid metabolism in poultry. Key genes, proteins, and pathways, such as FASN, FABP4, PPARG, C/EBPα, SLC27A1; LPL, APOA1, COL1A1; PPAR and ECM-receptor interactions signaling, have been identified to regulate IMF content and distribution by modulating fatty acid metabolism and adipogenesis. LncHLFF was innovatively found to promote ectopic IMF deposition in chickens via exosome-mediated mechanisms without affecting abdominal fat deposition. MiR-27b-3p and miR-128-3p were found to inhibit adipogenic differentiation by targeting PPARG, thereby affecting IMF formation. In nutrition, nutrigenomics research has shown that fructose enhances IMF deposition by activating ChREBP, providing new targets for nutritional interventions. Adjusting dietary components, including energy, protein, amino acids, fatty acids, and phytochemicals (e.g., rutin), has been shown to significantly improve meat quality in broilers. Maternal nutrition (e.g., intake of energy, amino acids, vitamins, and trace elements) and IOF (e.g., N-carbamylglutamate) have also been confirmed to significantly impact offspring meat quality, opening new avenues for improving embryonic nutrition. Based on these significant advancements, this review proposes strategies that integrate genetic and nutritional approaches. These strategies aim to modulate the differentiation fate of paraxial mesenchymal stem cells toward myogenic or adipogenic lineages and the interaction between muscle and adipose tissues. These insights would help to improve meat quality while ensuring the growth performance of broiler chickens.

Keywords: Chicken meat quality; Embryonic nutrition; Genetic regulation; Intramuscular fat; Nutritional intervention.

Fig. 1

Global poultry meat and pork production from 1980 to 2022. A Total global poultry meat and pork production. B Global chicken meat production and its proportion of total poultry meat. Source: Our World in Data (https://ourworldindata.org/)

Fig. 2

Regulatory networks of noncoding RNAs in preadipocytes and intramuscular fat (IMF) deposition. ACAA1: Acetyl-CoA acyltransferase 1; ACOX1: Acyl-CoA oxidase 1; ACOT13: Acyl-CoA thioesterase 13; AGPAT2: 1-acylglycerol-3-phosphate-O-acyltransferase 2; ANXA6: Annexin A6; circ: Circular RNA; CPT1A: Carnitine palmitoyl transferase 1 A; FDPS: Farnesyl diphosphate synthase; GATA6: GATA binding protein 6; GPAM: Glycerol‑3‑phosphate acyltransferase; lncRNA/lnc: Long noncoding RNA; miR: MicroRNA; MSTN: Myostatin; PPARG: Peroxisome proliferator activated receptor γ; RXRG: Retinoid X receptor γ; SCP2: Sterol carrier protein 2; TXNRD1: Thioredoxin reductase 1. The red upward arrow represents an increase. The question mark within the dashed brown box represents the target gene that has not yet been identified. Created by FigDraw (https://www.figdraw.com)

Fig. 3

Regulatory networks of noncoding RNAs in the regulation of myofiber type profiles. ACACA: Acetyl-CoA carboxylase alpha; CALM1: Calmodulin 1; circPTPN4: Circular RNA PTPN4; FGF18: Fibroblast growth factor 18; lncRNA/lnc: Long noncoding RNA; miR: MicroRNA; MYH1B: Myosin heavy chain 1B; NAMPT: Nicotinamide phosphoribosyltransferase; PC: Pyruvate carboxylase; PPARGC1A: Peroxisome proliferator-activated receptor gamma coactivator 1-alpha; SERCA2: Sarcoplasmic/endoplasmic reticulum Ca²⁺ transporting 2; SOX6: SRY-box transcription factor 6; Six1: SIX homeobox 1. Created by FigDraw (https://www.figdraw.com)

Fig. 4

Schematic diagram illustrating the role of enhancing embryonic nutrition in improving the meat quality of broiler chicks. IMF: Intramuscular fat. The red upward arrow represents upregulation, and the black downward arrow represents a decrease. Created by FigDraw (https://www.figdraw.com)

Fig. 5

Schematic representation of key genetic pathways in the gene-nutrition network regulating intramuscular fat (IMF). A range of regulatory factors collectively influence IMF formation and deposition in chickens. These factors include maternal nutrition, in ovo feeding (IOF), and direct uptake, as well as biological regulators such as hormones (green boxes), key transcription factors (pink boxes), and non-coding RNAs (ncRNAs; red dashed boxes), along with their target genes and associated pathways. All these elements interact to orchestrate the processes of IMF generation and accumulation. Blue dashed arrows indicate possible regulatory relationships, blue solid arrows indicate regulation, transport, or interaction, and red double-sided arrows indicate bidirectional regulatory relationships. The red upward arrow represents an increase. Figure 5 is based on the reports from [298] and [39], with some modifications. Additional annotations can be found in Supplementary Material 3. Created by FigDraw (https://www.figdraw.com)

Fig. 6

A schematic diagram for further research points in the targeted regulation of intramuscular fat deposition and improvement of meat quality. The solid arrows indicate the proliferation or differentiation of cells, and the dashed arrows represent interactions between nutrients and intercellular signaling. The red dashed rectangle and question mark indicate that these paths have not yet been fully investigated in chickens. FAPs: Fibro-adipogenic progenitors; MDSCs: Muscle-derived stem cells; MSCs: Mesenchymal stem cells. Created by FigDraw (https://www.figdraw.com)