Identification of microRNA Transcriptome Involved in Bovine Intramuscular Fat Deposition

Abstract

BackgroundIntramuscular fat deposition in beef is a major determinant of carcass quality and value in the USA. The objective of this study was to examine changes in microRNA (miRNA) transcriptome that are involved with intramuscular fat deposition with time-on-concentrates (TOC). Yearling steers were individually fed a high concentrate diet and changes in intramuscular fat deposition were monitored by real-time ultrasound at 28 to 33 d intervals. Longissimus muscle biopsies collected on d 0, 92 and 124 TOC to examine changes in miRNA transcriptome that are involved in intramuscular fat deposition.ResultsSteer body weight increased (P < 0.0001) at each weigh day during TOC. Fat thickness increased (P < 0.005) from d 28 to 124. Ribeye area was larger (P < 0.001) on d 124 than d 61, which was larger than d 0 and 28. Ultrasound intramuscular fat content was greater (P < 0.001) on d 92 and 124 compared to d 0, 28 or 61. Sequencing of the muscle biopsy samples identified one miRNA, bta-miR-122, that was up-regulated (P < 0.005) at d 92 and 124 compared to d 0. At d 92 TOC, mRNA expression levels of fatty acid binding protein 4 (FABP4) and elongase 6 (ELOVL6) were up-regulated (P < 0.01) compared to d 0; whereas at d 124, lipogenic genes involved in de novo fatty acid synthesis, fatty acid transport, elongation and desaturation were highly up-regulated compared to d0.ConclusionsSmall RNA sequencing identified bta-miR-122 as a potential miRNA of interest that may be involved in intramuscular fat deposition with increasing TOC. Increased intramuscular fat content, as measured by real-time ultrasound, combined with differential gene expression suggests that preadipocyte differentiation may be stimulated first, which is followed by a global up-regulation of lipogenic genes involved in de novo fatty acid synthesis that provide fatty acids for subsequent hypertrophy.

A review of the role of transcription factors in regulating adipogenesis and lipogenesis in beef cattle

“…Regarding the role of transcription factors and miRNAs, beef cattle, sheep and pigs all involve PPARγ, miRNAs and other transcription factors in regulating lipid metabolism and IMF content (Duckett & Greene, 2022; Feng et al., 2022; Han et al., 2021). While these commonalities exist, there are differences in how these factors operate in each species.…”

Verification of Key Target Molecules for Intramuscular Fat Deposition and Screening of SNP Sites in Sheep from Small-Tail Han Sheep Breed and Its Cross with Suffolk

“…Further, the Protein–Protein Interaction (PPI) prediction analysis indicated that the PVALB gene was the highest hub gene. Susan K. Duckett [ 20 ] demonstrated that bta-miR-122 may be related to IMF deposition by conducting miRNA transcriptome sequencing on bovine longissimus dorsi muscle tissue. By transcriptome sequencing analysis of chicken pectoral and abdominal muscles, Na Luo [ 21 ] reported that the IMF deposition in pectoral muscles was associated with pyruvate and citrate metabolism through genes such as GAPDH , LDHA , GPX1 , and GBE1.…”