The association between acyl-CoA synthetase (ACSL4) polymorphism and intramuscular fat content in (Landrace × Yorkshire) × Duroc pigs.

The aim of the study was to check whether different genotypes at acyl-CoA synthetase (ACSL4 locus, SNP G2645A) are associated with pork quality. 132 (Landrace × Yorkshire) × Duroc fatteners were genotyped by originally developed PCR-RFLP method. Upon the slaughter, the samples of longissimus lumborum muscle were taken from each carcass to determine the following parameters: content of water, protein and fat, pH (45 min, 24, 48, 96, and 144 h post mortem), electrical conductivity, drip loss, meat lightness, glycolytic potential, glycogen and lactate contents in meat. Among several associations observed, the highly significant (p<0.01) was found for intramuscular fat (IMF) content. Pigs with genotype GG revealed the highest content of IMF - 2.47%.

Screening 52 single nucleotide polymorphisms for extreme value of glycolytic potential and drip loss in pigs.

Summary Low heritability of meat quality traits and the lack of their systematic registration in breeding programs have encouraged the search for single nucleotide polymorphisms (SNPs) located within genes coding the proteins involved in muscle and fat metabolism. In this report, a panel of 52 SNPs was used to find which alleles and genotypes are more/less frequent in groups of pigs differentiated by extreme value of glycolytic potential (GP) and drip loss (DL). The analysis was carried out in 52 fatteners (chosen from 246 pigs), of which 28 were Landrace and 27 Landrace x Yorkshire. Two designs were performed: I, fatteners were divided into two groups showing extreme value of GP (<125 versus >145), II, fatteners were divided into two groups showing extreme value of DL (<6.0 versus >6.0). Allele frequency differences between the phenotypic groups of extreme GL or DL were not influenced by the breed. The frequency of 52 SNPs alleles for each of group was calculated and a chi-squared test was used to estimate the significance of differences in allele frequencies between alternative groups in each experimental design. Three SNPs (DECR1, PPARGC1, MC4R) and another two (CYP21, SFRS1) showed significant differences between groups of extreme GP and DL, respectively. To exemplify and validate potential associations of candidate SNPs for GP and DL, 293 fatteners representing three commercial breeds/crosses (95 Landrace, 66 Landrace x Yorkshire and 132 Landrace x Yorkshire x Duroc were genotyped for DECR1 and CYP21 by PCR-RFLP assays. DECR1 showed significant associations with GP in Landrace and Landrace x Yorkshire x Duroc fatteners. CYP21 showed significant associations with DL in all breeds/crosses. Interestingly, the CYP21 polymorphism revealed adverse associations trend in Landrace x Yorkshire x Duroc pigs in comparison to Landrace and Landrace x Yorkshire fatteners.

The expression of genes PKM2 and CAST in the muscle tissue of pigs differentiated by glycolytic potential and drip loss, with reference to the genetic group.

The present studies aimed at an analysis of the expression level of genes PKM2 and CAST in Longissimus lumborum [LL] muscle tissue of pigs differing as regards the glycolytic potential [GP] and drip loss [DL] from the LL muscle, with reference to the genetic group. The studies covered a total of 65 pigs: 20 purebred Landrace [L], 22 crossbreeds of Landrace with the Yorkshire [L x Y] and 23 three-breed crosses (Landrace x Yorkshire) x Duroc [(L x Y) x D]. In the case of gene PKM2 one may observe in (L x Y) x D crossbreds, compared to L x Y crossbreds, an increased expression, closely related with the increase in dry matter content, including intramuscular fat, as well as a more favourable progress of glycolytic and energy metabolism during the early time post mortem (pH(45) and R(1)). Compared with Landrace animals, the lower expression of the CAST gene observed in (L x Y) x D pigs is manifested by a marked improvement of meat quality (R(1) pH(45) pH(24), pH(48)), arising from the rate of glycolytic and energy metabolism, typical for normal meat, that in effect results in its higher culinary and technological value.

The association between polymorphism of PKM2 gene and glycolytic potential and pork meat quality.

The objective of this study was to investigate the association of PKM2 gene with glycolytic potential and meat quality traits in three groups of fatteners - Landrace, Landrace x Yorkshire and (Landrace x Yorkshire) x Duroc. The present study was conducted on 243 fatteners, free of RYR1(T) gene, which 95 were of Landrace breed and the rest were the following crosses: 66 - Landrace x Yorkshire and 82 (Landrace x Yorkshire) x Duroc. It has been stated, that PKM2 gene (independently from the breed) was significantly associated with GP, lactate content, R(1) indicator, pH and drip loss. The presence of TT genotype may lead to increase of GP and lactate content and results in low pH(24) and pH(144) and bigger drip loss measured 96 and 144 h after the slaughter. Except for the landrace fatteners, the association of the PKM2 gene with the glycogen content has not been statistically confirmed. Statistically confirmed interaction shows, that the association of PKM2 gene with glycolytic potential and glycogen content concerns mainly the Landrace pigs. Moreover, a high (almost 89%) conformability of the genotype of PKM2 gene with the RN(-) phenotype, can serve as an additional argument in favour of the thesis.

The effect of interaction between genotype CAST/RsaI (calpastatin) and MYOG/MspI (myogenin) on carcass and meat quality in pigs free of RYR1(T) allele.

The purpose of the studies was to demonstrate to what degree genotypes of calpastatin (CAST/RsaI) and myogenin (MYOG) genes as well as the interaction between them may affect the carcass and meat quality of pigs. The investigations were conducted on 397 stress resistant pigs (free of RYR1(T) allele). It was demonstrated that the favourable effect of the variants of CAST and MYOG genes on carcass quality traits depends on the cut. The gene variant favourably affecting the weight of ham simultaneously had a negative effect on the weight of the loin. It was also shown that the interaction between CAST and MYOG genotypes has a significant effect on backfat thickness. The effect of a given combination of CAST and MYOG genotypes on carcass traits is related to the weight of a substantial cut (ham, loin). Genotypes at loci CAST/RsaI and MYOG have a significant effect on the value of certain traits and parameters of meat quality and its technological value (genotype CAST on pH at 35min and 2, 3, 24, 48, 96, 144h post-mortem (pH(35), pH(2), pH(3), pH(24), pH(48), pH(96), pH(144), respectively), R(1) (IMP/ATP), electrical conductivity at 3 and 4h post-mortem (EC(3), EC(4)), technological yield of meat in curing and thermal processing (TY) and protein content in the muscle tissue, while genotype MYOG on pH(48), EC(35), EC(3), EC(24) and dry matter content).

Association of calpastatin (CAST/MspI) polymorphism with meat quality parameters of fatteners and its interaction with RYR1 genotypes.

The aim of this study was to analyse the effect of polymorphism of calpastatin (CAST) and RYR1 genes for some meat quality traits taking into consideration the group of meatiness and their mutual interactions. Investigations were carried out on a group of 201 fatteners which were crosses of four breeds. The results obtained show that CAST/MspI genotype has an effect close to the major effect for drip loss from LL muscle tissue at 48 h as well as at 96 h postmortem (0.92 and 0.96 SD respectively). Among the meat quality traits analysed and that were affected by CAST/MspI genotype, the animals with BB genotype at this locus were characterized by the most profitable values of all these traits. Significant interactions between CAST and RYR1 genotypes observed indicate that the quality of meat influenced by RYR1 genotype may be modified by the simultaneous influence of genotype as regards the CAST locus.

The interaction between calpastatin and RYR1 genes for some pork quality traits.

This study was performed in order to investigate a relationship between polymorphism's of calapastatin gene (CAST) identified with HinfI, MspI and RsaI restriction endonucleases in pigs and meat quality characteristics and also interactions between CAST and RYR1 genes. Investigations were carried out on group of 89 fatteners being crosses of (Polish Large White×Polish Landrace)×(Hampshire×Pietrain). Some meat quality characteristics, glycolytic potential of LL muscle, yield of curing meat in cooking, the yield of loin in curing and smoking processes were determined. Statistically significant influence of RYR1 genotype (CC and CT) on investigated traits wasn't affirmed. A significant effect of CAST genotype on the value of several meat quality traits was noticed. Interactions between RYR1 and CAST genes were statistically significant for pH(45) value (CAST/RsaI×RYR1) and for drip loss (CAST/HinfI×RYR1). Obtained results showed that glycogen level in LL muscle in 45 min post mortem depends on CAST/MspI and CAST/RsaI genotypes while glycolytic potential depends on CAST/RsaI genotype. Genotyp AA at CAST/RsaI locus and AA genotype at CAST/HinfI locus stopped disclose of effect of RYR1 gene mutation for pH(45) in LD muscle and for drip loss respectively. Animals heterozygous in RYR1 locus (CT) being BB homozygotes at CAST/RsaI locus produced meat with highest pH(45) value (6,4) and dark meat colour. For technological properties of meat most interesting are double heterozygotes at the loci RYR1 and CAST/HinfI with significantly lowest (P⩽0.01) drip loss (4,04%).

Muscle glycogen level and meat quality in pigs of different halothane genotypes.

The halothane genotype of 22 Polish landrace pigs was determined using halothane test and blood typing. Eight homozygous normal (NN), eight hetero-zygotes (Nn) and six homozygous recessive (nn) were identified. The levels of glycogen and lactate were measured in biopsy samples taken from the longissimus lumborum using a shot biopsy technique. pH (pH(1)) and IMP/ATP ratio (R) were determined at 30 min after slaughter, while pH, meat colour and water holding capacity were determined on the day after slaughter. The halothane genotype did not affect intra vitam glycogen level. The nn pigs had a higher R value and lower pH(1) than both Nn and NN animals. Heterozygous animals were intermediate between both homo-zygotes for biopsy lactate level and meat colour. The lactate content of biopsy samples was significantly correlated with pH(1) (r = -0·68; P < 0·01), R (r = 0·68; P < 0·01), meat colour (r = 0·57; P < 0·01) and water holding capacity (r = 0·45; P · 0·05).

Enzyme entrapped polypyrrole modified electrode for flow-injection determination of glucose.

Immobilization of glucose oxidase in electropolymerized polypyrrole film on the surface of a platinum wire electrode, provides a convenient sensor for flow-injection glucose determination. An upper limit of linear response for 100 microliters injected sample volume was estimated as 20 mM, whereas a 500 microliters injected sample volume gave an estimated detection limit of 0.5 mM. A simple electrode preparation procedure allows quick electrode renewal before each series of measurements.