Integrating metabolomic and transcriptomic to reveal the dynamics of ntramuscular fat in chicken meat

In this study, we investigated the dynamic changes of intramuscular fat (IMF) deposition in the breast muscle of Jingyuan chickens at different stages (42-, 126- and 180-day-old) using metabolomics. pH45min, a*, and L* were significantly increased in the breast muscle of 126-day-old chickens, and IMF content and b* were significantly increased in the breast muscle of 180-day-old chickens. A total of 4,643 differentially expressed metabolites (DEMs) were identified, of which 10 decreased and 29 increased with age. Key pathways associated with meat quality included oxidative phosphorylation, ß-alanine metabolism, and glycerophospholipid metabolism. Combined transcriptomic and phenotypic correlation analyses revealed significant positive correlations of IMF, pH45min, a*, and L* with LysoPC 20:4, CD3E, TARP, IL7R, ENSGALG00010025331, and RASSF5. In the 42- and 180-day-old chickens, IMF, pH45min, a*, and L* were significantly and positively correlated with L-Anserine, Dihydroxyacetone phosphate, ENSGALG00010006904, and HSPB7. IMF, pH45min, a*, and L* were significantly and positively correlated with beta-Nicotinamide adenine dinucleotide in the 126- and 180-day-old. This study deepens our understanding of the differences in IMF deposition at different stages of Jingyuan chickens and its relationship with meat quality. Overall design: A total of 300 1-day-old Jingyuan chicks were reared at the Jingyuan Chicken National Breeding Farm (Panyang County, China) using standardized temperature and humidity. All chicks were always fed and watered ad libitum under the same conditions. Group B1 was slaughtered at 42 days of age (0.422 ± 0.03 kg), Group B2 was slaughtered at 126 days (1.68 ± 0.14 kg), and Group B3 was slaughtered at 180 days (2.03 ± 0.09 kg). After rendering the hens unconscious with ether respiratory anesthetic, we severed their carotid arteries to end their lives. The remaining breast muscles were snap-frozen in liquid nitrogen and kept in a refrigerator at -80 °C after whole muscles were gathered for the purpose of determining the quality of the meat. Subsequently, 30 hens of consistent weight were chosen from each age group, and the transcriptome and non-targeted metabolome sequencing were performed on their breast muscles.