Impact of the leptin receptor gene on pig performance and quality traits

Abstract

The recessive T allele of the missense polymorphism rs709596309 C > T of the leptin receptor gene is associated with intramuscular fat. However, its overall impact on pork production is still partial. In this work, we investigated the all-round effects of the TT genotype on lean growth efficiency and carcass, meat and fat quality using data from an experiment that compared the performance of 48 TT and 48 C- (24 CT and 24 CC) Duroc barrows. The TT pigs were less efficient for lean growth than the C- pigs. Although heavier, their carcasses had less lean content, were shorter and had lighter loins. Apart from increasing marbling and saturated fatty acid content, changes caused by the TT genotype in meat and fat quality are likely not enough to be perceived by consumers. The effect on visual marbling score exceeded that on intramuscular fat content, which suggests a direct influence of the T allele on the pattern of fat distribution in muscle. With current low-protein diets, the T allele is expected to be cost-effective only in niche markets where a very high level of marbling is critical.

Keywords: Feed intake; Growth; Intramuscular fat; Leptin; Meat quality; Swine.

Figure 1

Average reads per kilobase per million mapped reads (RPKM) of (A) leptin receptor (LEPR) and (B) leptin (LEP) transcripts by LEPR genotype (TT, CT and CC).. Within transcript, means with different letters differ (P₀ > 0.95). P₀: Posterior probability of the difference between genotypes being greater (if positive) or lower (if negative) than zero. Leptin receptor expression was different between LEPR genotypes (P₀ > 0.99, between TT and CT, and P₀ = 0.98, between CT and CC) while leptin expression differed between TT and CT (P₀ > 0.99), but not between CT and CC (P₀ = 0.50).