Gene Expression of Peroxisome Proliferator-Activated Receptor ? in Mangalica and Large White Pigs

Abstract

The expression of peroxisome proliferator-activated receptor ? gene (PPAR?) – a major regulator of adipogenesis and intramuscular fat deposition in pigs – was analysed in different tissues of Blonde Mangalica (M) and Hungarian Large White (LW) by means of quantitative reverse transcription PCR. In total, 20 experimental animals were raised and fed under identical conditions, and transported to the abattoir at similar body weight (124.7±10.3 kg; p>0.05). In both breeds highest PPAR? expression was observed in backfat (p<0.001), whereas lower levels were measured in muscle samples. The PPAR? mRNA levels in loin (m. longissimus dorsi) and semimembranosus muscle samples did not differ (p>0.05). Elevated PPAR? expression was observed in M backfat compared to LW (p<0.05). Loin and semimembranosus muscle samples of M showed higher PPAR? mRNA levels than LW (P<0.001), as well. Loin muscle marbling scores significantly correlated with ß-actin normalized PPAR? expression (r=0.63; p<0.001) indicating the involvement of PPAR? in the regulation of intramuscular fat development. In conclusion, the differential expression of PPAR? in backfat and muscle samples can contribute to the remarkable differences in the constitution and intramuscular fat accumulation of fat-type M and lean-type commercial LW. Muscle PPAR? mRNA levels may be used as an indicator of marbling characteristics in pigs.