Influence of obesity gene in quantitative traits of swine

Abstract

Genotype data of 477 animals of several swine races (Landrace -LD, Large White -LW, Pietrain -PI, LWXLDXPI, Piau, Monteiro, and unknown race) were obtained to determine the allele frequency of the obesity gene. Genotype data of 174 crossbred swine (LWXLDXPI) were also obtained, in order to assess its correlation with carcass evaluation data (lean meat percentage, backfat thickness at P2, loin eye area, adjacent fat area, total fat and meat). Finally, genotype data of 96 pure swine (Landrace, Large White and Pietrain) were collected, to establish its relation with meat quality (drip loss, meat color, texture analysis and intramuscular fat) and carcass evaluation data (lean meat percentage; ham, loin, shoulder and belly weights; and backfat thickness at P2). This work also aimed associating EPDs (expected progeny differences) for litter size, daily weight gain and backfat thickness with genotype data of 49 Large White males and 54 Landrace females. Genotyping was done on animal blood by PCR-RFLP, based on Stratil et al. (1997). Statistical analysis was done by using SAS software for variance analysis between genotypes and data for each cited class. For purebred animals, a mixed model was used, with sire within race as random effect. The allelic frequencies of alleles T and C were, respectively: 0.8142; 0.1857 (Landrace); 0.9125; 0.0875 (Large White); 0.9433; 0.0566 (Pietrain); 0.8333; 0.1666 (LWXLDXPI); 0.2500; 0.7500 (Piau); 0.8750; 0.1250 (Monteiro), and 0.8870; 0.1130 (unknown race). Since the highest allele C frequency occurred in Piau, we suggest that this allele could be associated with fat accumulation. In the Landrace race, a study was done separating the frequencies of 2 generations (great-grandfather and grandfather), and the differences confirmed by a Chi-square test, a higher frequency of allele C having been found in the grandparental generation. This suggests that this allele could be eliminated by selection from the great-grandparental generation, when the male grandparent is replaced by the great-grandparental generation. The obesity gene did not influence any of the carcass evaluation data from crossbred animals. In pure swine, where the only genotypes were TT and TC, it greatly influenced shoulder weight and meat texture, with the highest average in heterozygotes (shoulder: 4.07 vs. 3.93; texture: 2.62 vs. 1.82), suggesting better carcass quality and worse meat quality than in homozygotes. The obesity gene did not influence any trait in the expected progeny difference (EPD) study.

Effect of g.2728G>A and g.3996T>C Polymorphisms at the Leptin Gene Locus on Microstructure and Physicochemical Properties of longissimus lumborum Muscle of Polish Landrace Pigs

“…The comparison of meat quality traits (Table 1) did not reveal differences in pH 45min and pH 24h between the analysed genotypes. Our results are similar to those reported by BORGES & GOULART (2002), who identified g.3469T>C polymorphism in the populations of Landrace, Large White and Pietrain pigs but also did not find the effect of animal genotype on pH of meat. In addition, in the present study, no significant differences in shear force values were identified between GA and GG genotypes.…”

“…This is confirmed by LARZUL et al (1997) and RYU & KIM (2005), who showed positive correlations between parameters of L* colour and parameters of type IIB muscle fibres. Meanwhile, BORGES & GOULART (2002), who identified 3469T>C polymorphism in the leptin gene in Landrace, Large White and Pietrain pigs, showed no relationship between animal genotype (TT, TC) and meat colour. This may be due to the fact that meat colour, like other meat traits, is affected by several factors such as IMF content, pH and water binding in muscle, the interaction of which determines the variation of this parameter.…”

Obese gene polymorphism in Pietrain and large white pigs after a divergent selection

“…The genotype frequencies observed were consistent with those reported by Borges and Goulart (2002) who, when genotyping 80 Large White pigs, observed 82.5% TT, 17.5% TC and no CC, and when analyzing 53 Pietrain animals, found 90.56% TT genotypes, 7.54% TC and 1.88% CC. The same allele frequencies were found by Borges and Goulart (2002), Stratil et al (1997), Korwin-Kossakowska et al (2001), Kulig et al (2001), and Szydlowski et al (2004) when studying other pig breeds.…”

“…The same allele frequencies were found by Borges and Goulart (2002), Stratil et al (1997), Korwin-Kossakowska et al (2001), Kulig et al (2001), and Szydlowski et al (2004) when studying other pig breeds.…”

“…Jiang and Gibson (1999) found a positive correlation between C allele and the body fat rate in the Meishan breed. Borges and Goulart (2002) suggested that the C allele may be associated with fat accumulation. Later, Kuryl et al (2003) concluded that the TT genotype may be more advantageous since it is associated with lower fat deposition in carcass when compared to TC.…”