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Advisor(s)
Abstract(s)
Background: Both 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.
Results: The 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.
Conclusions: Overall, 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.
Description
Articles in International Journals
Keywords
Beef cattle Adipose tissue Muscle Gene expression Fat deposition
Pedagogical Context
Citation
COSTA, A.S.H., et al. (2013). Expression of genes controlling fat deposition in two genetically diverse beef cattle breeds fed high or low silage diets. BMC Veterinary Research, 9(118), 1-16. doi: 10.1186/1746-6148-9-118
Publisher
BioMed Central