INVESTIGATION OF CATHEPSIN B (CTSB) and CATHEPSIN L (CTSL) POLYMORPHISM FOR CARCASS AND MEAT QUALITY IN SWINE

Abstract

The objectives of the research were to evaluate genotype frequencies and to investigate
polymorphism in the cathepsin B gene (CTSB) and cathepsin L gene (CTSL) with carcass and meat quality in
288 crossbreeds (large white x landrace x duroc). Pigs whose weights ranged from 78-134 kg were assigned to
slaughter. PCR-RFLP protocols were used to identify polymorphisms of both genes. The frequencies of AA, AC
and CC genotypes of CTSB were 0.340, 0.615, and 0.045, respectively. The frequencies of A and C alleles of
CTSB were 0.648 and 0.352, respectively. Regarding CTSL, the frequencies of CC, CT and TT genotypes were
0.625, 0.354, and 0.021, respectively. The frequencies of C and T alleles of CTSL were 0.802 and 0.198,
respectively. The significant effects of CTSB polymorphism were detected on body length (BL), scan of loin eye
area (U_LAE), loin eye area (LAE), and weight loss (WL) (P<0.05). The pigs carrying the AC genotype had
higher level of BL, U_LEA and LEA than the ones carrying the homozygous genotype (AA or CC). The pigs
with the CC genotype of CTSB had lower WL (1.86 kg) than the ones carrying the AA or the AC genotype (2.19
and 1.97 kg). The CTSL variants represented statistically significant effects on BL trait (P<0.05). The CC
genotype (77.92 cm) had higher BL value compared to the CT (76.14 cm) and the TT genotypes (76.92 cm). The
CTSB and CTSL were high polymorphism and their alleles could be as the potential genetic markers for swine
selection.