Expression of genes controlling fat deposition in two genetically diverse beef cattle breeds fed high or low silage diets

Abstract

BackgroundBoth genetic background and finishing system can alter fat deposition, thus indicating their influence on adipogenic and lipogenic factors. However, the molecular mechanisms underlying fat deposition and fatty acid composition in beef cattle are not fully understood. This study aimed to assess the effect of breed and dietary silage level on the expression patterns of key genes controlling lipid metabolism in subcutaneous adipose tissue (SAT) and longissimus lumborum (LL) muscle of cattle. To that purpose, forty bulls from two genetically diverse Portuguese bovine breeds with distinct maturity rates, Alentejana and Barrosã, were selected and fed either low (30% maize silage/70% concentrate) or high silage (70% maize silage/30% concentrate) diets.ResultsThe results suggested that enhanced deposition of fatty acids in the SAT from Barrosã bulls, when compared to Alentejana, could be due to higher expression levels of lipogenesis (SCD and LPL) and β-oxidation (CRAT) related genes. Our results also indicated that SREBF1 expression in the SAT is increased by feeding the low silage diet. Together, these results point out to a higher lipid turnover in the SAT of Barrosã bulls when compared to Alentejana. In turn, lipid deposition in the LL muscle is related to the expression of adipogenic (PPARG and FABP4) and lipogenic (ACACA and SCD) genes. The positive correlation between ACACA expression levels and total lipids, as well trans fatty acids, points to ACACA as a major player in intramuscular deposition in ruminants. Moreover, results reinforce the role of FABP4 in intramuscular fat development and the SAT as the major site for lipid metabolism in ruminants.ConclusionsOverall, the results showed that SAT and LL muscle fatty acid composition are mostly dependent on the genetic background. In addition, dietary silage level impacted on muscle lipid metabolism to a greater extent than on that of SAT, as evaluated by gene expression levels of adipogenic and lipogenic factors. Moreover, the response to diet composition evaluated through mRNA levels and fatty acid composition showed interesting differences between Alentejana and Barrosã bulls. These findings provide evidence that the genetic background should be taken into account while devising diet-based strategies to manipulate fatty acid composition of beef cattle tissues.

RNA-Seq transcriptomics and pathway analyses reveal potential regulatory genes and molecular mechanisms in high- and low-residual feed intake in Nordic dairy cattle

“…The upregulation of the ACACA gene in the high-RFI Holstein group in this network is also interesting in relation to functions in feed utilization. A positive relationship has been reported between ACACA enzyme activity and intramuscular fat levels [40]. In addition, the negative relationship between the ACACA gene and other lipogenesis pathway genes and milk production in dairy cattle was also confirmed by Sumner-Thomson et al (2011) [41].…”

Molecular genetics-nutrition interactions in the expression of AANAT, ADRB3, BTG2 and FASN genes in the heart, kidney and liver of Australian lambs supplemented with Spirulina (Arthrospira platensis)

“…Fatty acids have been increasingly recognised as major biological regulators of the quality of fresh meat and sensory value of meat products. In addition, fatty acids can influence sterol metabolism, signal transduction, enzyme activities, cell proliferation, differentiation and receptor expression (Da Costa et al 2013). The cellular effect of fatty acids is related to the regulation of gene expression, subsequent downstream events and omega-3 fatty acids are especially potent in affecting many of the metabolic pathways (Kashani et al 2015;Deckelbaum et al 2006).…”

Intermuscular and intramuscular adipose tissues: Bad vs. good adipose tissues

“…One end point of this selection pressure is IM. 35 Meat animals such as beef cattle are fed a grain diet in a feedlot setting prior to slaughter in order to allow the IM to form. 36 This feeding regimen is costly, but provides consumers a meat product with adipose cells interspersed among skeletal muscle fibers in the final meat product resulting in a meat product that is flavorful and juicy.…”