N6-methyladenosine (m⁶A) is the most prevalent internal mRNA modification in eukaryotes. The M⁶A modification plays an important role in transcription and cell function. The mechanism by which m⁶A modification regulates meat quality remains elusive. In this study, gene knockout and overexpression were used to explore m⁶A-modified regulation of meat quality. The content of PCK2 in blood increased significantly with the increase of Rex rabbits’ age. PCK2 expression levels in the longissimus lumborum and liver also increased significantly with the increase of Rex rabbits’ age. However, the expression level of PCK2 showed no significant difference in adipose tissue. In cell experiments, we found that METTL3 inhibited adipocyte differentiation by targeting the PCK2 gene via the recognition function of YTHDF2. Finally, the results of correlation analysis showed that PCK2 expression was positively correlated with intramuscular fat, whereas PCK2 expression was negatively correlated with total water loss rate at three different stages. In addition, PCK2 expression was also negatively correlated with reduced pH value at 75 and 165 days. Intramuscular fat content, pH and muscle water holding capacity are the main factors affecting the taste and flavor of muscle. Therefore, N6-methyladenosine regulated muscle quality by targeting the PCK2 gene.

Hair follicle development directly affects the development of the rabbit fur industry. The growth and development of a hair follicle is modified and regulated by many genes and mechanisms. M⁶A is an important RNA modification. However, there are few studies on the effects of the regulation of m⁶A on hair follicle growth and development. In this study, hematoxylin–eosin (HE) staining was used to explore the difference in hair follicle development between Rex rabbits and Hycole rabbits, and we performed m⁶A sequencing to identify the key genes with m⁶A modification in hair follicle growth. The results showed that the hair length, coarse hair percentage, primary hair follicle ratio, and skin thickness of Hycole rabbits were significantly higher than those of Rex rabbits. However, the proportion of secondary hair follicles in Hycole rabbits was significantly lower than that in Rex rabbits. In addition, we found five differential methylases, 20 differential genes, and 24 differential signaling pathways related to hair growth and development. The results of the Sankey diagram showed that 12 genes were related to 13 signal pathways. Finally, we found that five methylases regulated the development of hair follicles through differential genes/signal pathways. These findings laid a molecular foundation for the function of m⁶A modification in hair development.

Background Rabbit meat is a high-protein, low-fat food with recognized nutritional benefits, often labeled as “healthy meat” and “nootropic meat.” However, its low-fat content leads to relatively poor flavor. Myofibers are the main components of rabbit meat, and their type composition determines the overall metabolic characteristics of the meat, which ultimately affects fresh meat quality. During the growth of rabbits, muscle fibers transform into one another. Nevertheless, the changes in the relative composition of myofiber types as domestic rabbits grow, and the molecular mechanisms behind myofiber transformation, remain unclear. This study aimed to analyze the changes in the relative composition of myofiber types in rabbits of different ages and explore the roles of various potential molecules in rabbit myofiber transformation at the transcriptional level using whole transcriptome technology. Results Significant differences were observed in the relative composition of gluteus (GLU) and gastrocnemius (GAS) muscle fiber types, which impacted rabbit meat color and taste. During growth, the relative composition of GLU muscle fiber types differed significantly between 1-day-old and 14-day-old rabbits. Transcriptome analysis of GLU muscle from these two age groups revealed extensive molecular changes during myofiber transformation, including 3,194 differentially expressed mRNAs, 366 circRNAs, 1,394 lncRNAs, 343 miRNAs, 180 differentially expressed transcription factors, and 2,717 genes with significant alternative splicing. These differentially expressed molecules were associated with multiple signaling pathways involved in myofiber transformation, such as the AMPK, calcium, PI3K-Akt, MAPK, Hippo, and mTOR pathways. Comprehensive co-expression and protein-protein interaction analyses identified an active interconnected module containing 38 co-expressed proteins related to myofiber transformation. Based on the ceRNA theory and these 38 key molecules, a lncRNA/circRNA-miRNA-mRNA network was constructed, involving 9 mRNAs, 10 circRNAs, 18 lncRNAs, and 14 miRNAs. Conclusions This study investigated how the relative composition and content of myofiber types change during different growth stages of rabbits, and revealed the complex dynamic biological mechanisms underlying myofiber transformation in rabbits through whole transcriptomics. The results of this study can help identify appropriate targets for regulating myofiber transformation, thereby facilitating the development of high-quality rabbit meat.

Rabbit meat is a high-protein, low-fat food with recognized nutritional benefits, often labeled as “healthy meat” and “nootropic meat.