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Open access

Mirosław Tyra and Grzegorz Żak

Analysis of Relationships Between Fattening and Slaughter Performance of Pigs and the Level of Intramuscular Fat (IMF) in Longissimus Dorsi Muscle

The aim of the study was to determine the level of basic fattening and slaughter traits (growth rate, level of meatiness and fatness, age at slaughter) depending on different levels of intramuscular fat that determine different sensory perceptions of consumers. Subjects were 4430 gilts from pedigree farms, which were tested in performance stations. The breed composition of the animals was as follows (head): Polish Large White - 1240, Polish Landrace - 2083, Puławska - 104, Hampshire - 35, Duroc - 152, Pietrain - 208, line 990 - 608. Animals were kept in individual pens and fed standard diets. Intramuscular fat (IMF) content of the longissimus dorsi muscle was determined by Soxhlet using the SOXTHERM SOX 406 system (Gerhardt). The level of IMF served as a basis for dividing the test animals into three groups: below 2% (group I), between 2% and 3% (group II) and above 3% (group III). Animal breed had the highest and highly significant effect on the level of all traits analysed. As regards age at slaughter and carcass meat percentage, an interaction was found between animal breed and the group factor determined based on IMF level (P≤0.001). The factor expressed as IMF group had no effect on the level of analysed traits (P>0.05). Therefore, the results of this analysis concerning the parameters obtained from live evaluation do not permit these data to be used in selection for improved IMF levels. The high rate of lean deposition in the modern breeds prevented genetic differences in the level of IMF to fully manifest themselves at a slaughter weight of about 100 kg. This unfavourable information leads one to look for other factors that determine variation of this trait.

Open access

Mirosław Tyra and Grzegorz Żak

Abstract

The aim of the study was to estimate coefficients of heritability for intramuscular fat (IMF) content and other fattening, slaughter and meat quality traits of the pig breeds raised in Poland. In addition, genetic correlations were estimated between IMF content and a group of fattening, slaughter and meat quality traits, which enables this parameter to be included in the BLUP estimation of breeding value. The experiment used Polish Landrace (PL), Polish Large White (PLW), Puławska, Hampshire, Duroc, Pietrain and line 990 animals. A total of 4430 gilts of these breeds, tested at Pig Performance Testing Stations (SKURTCh), were investigated. Heritability of IMF was at intermediate level for the two most common breeds raised in Poland (h2 = .318 for PLW, h2 = .291 for PL). In the group of meat quality traits, high heritability was noted for meat colour lightness (L*) measured by Minolta (from h2 = .453 to h2 = .572). No relationships were found between IMF level and indicators of fattening performance. The highest value observed in this group of traits concerned the genetic relationship with daily feed intake (rG = .227) for the entire group of animals. For the PLW and PL breeds, these relationships were with feed conversion (kg/kg gain) (rG = .151 and rG = .167, respectively). One of the higher relationships observed were genetic correlations with water holding capacity (above rG = -.3) and, for the PLW and PL breeds, with meat redness (a*), which amounted to rG = .155 and rG = .143, respectively.

Open access

Magdalena Sobczyńska, Tadeusz Blicharski and Mirosław Tyra

Abstract

Relationships between performance test traits (growth rate, backfat thickness, loin depth, lean meat percentage, exterior, phenotypic selection index) and longevity traits (length of productive life, number of litters, total number of weaned pigs, number of weaned piglets per year, number of litters per year) in Landrace sows were evaluated using canonical correlation analysis. The data set consisted of 23,012 purebred sows that farrowed from 1994 to 2011 in 161 herds. The first three canonical correlations (0.37, 0.25, 0.07) were highly significant (P<0.0001). Correlations of the first canonical variate with the original measured variables indicated that sows with high values for this variate had lower growth rate (r=-0.31) and loin depth (r=-0.43), greater backfat thickness (r=0.23), as well as being older at birth of their last litter (r=0.98). These sows also had a greater number of litters (r=0.94) and better lifetime efficiency (r=0.61 and r=0.70 for number of weaned piglets per year and number of litters per year, respectively). Canonical loadings for the second canonical function indicate that sows with high values for the second set of variates had high growth rate (r=0.79) and phenotypic selection index (r=0.83), excellent conformation (r=0.62), as well as better efficiency in pig production (r=0.67). The squared multiple correlations show that the first canonical variate of the performance traits is a poor predictor of longevity (0.13) and nearly useless for predicting efficiency traits (0.07). Performance test traits explain 11% of the variance in the variables of longevity and lifetime productivity, whereas dependent variables explain only 3% of the variance in performance test traits. The relationships between performance test data and subsequent lifetime productivity or longevity were significant and unfavourable but low for Polish Landrace population

Open access

Katarzyna Ropka-Molik, Przemysław Podstawski, Katarzyna Piórkowska and Mirosław Tyra

Abstract

The microsomal triglyceride transfer protein via participation in transport of neutral lipids between membrane vesicle is essential for assembly of chylomicrons, low-density lipoproteins (LDL), and very low-density lipoproteins (VLDL). In human and pigs, it has been confirmed that mutations within MTTP locus affected lipid-transfer activity of this protein. The aim of the present study was to establish potential influences of ENSSSCP00000009789.2:p.Leu840Phe polymorphism on a panel of meat texture parameters measured in two muscles: m. longissimus lumborum and m. semimembranosus. The research performed on 410 pigs showed that investigated missense polymorphism was associated with meat texture profile parameters – TPA (hardness, cohesiveness, springiness, resilience, chewiness) as well as firmness and toughness estimated in loin muscle. In whole analyzed population, the meat of pigs with CC genotype was characterized by significantly the lowest value of TPA characteristic and this trend was also confirmed in two breeds (Puławska and Large White pigs). In turn, the results obtained for firmness and toughness parameters in longissimus lumborum were not consistent across the different populations studied. Our research, in connection with previous studies, indicated that the MTTP gene may be considered as a candidate gene responsible for pork quality traits and pinpointed a need for further analysis in order to select useful genetic markers associated with meat quality parameters.

Open access

Katarzyna Piórkowska, Kacper Żukowski, Tomasz Szmatoła, Katarzyna Ropka-Molik and Mirosław Tyra

Abstract

A high meat percentage in the porcine carcass has been achieved as a result of selection, but it has contributed to a deterioration of pork quality. The level of intramuscular fat has significantly declined, the pork has lost its tenderness and drip loss in meat has substantially increased, which has led to a deterioration of meat flavour and its technological suitability. The recovery of good pork quality could be supported by the development of genetic markers enabling faster breeding progress. This study presents a method by using RNA-seq data that identifies new variants for a chromosome region rich in QTLs for pork quality and selects gene candidates for these traits. This work included two pig breeds: the Polish Landrace (PL) and Puławska (PUL), which differ in meat quality and fat content. The transcriptome profile was estimated for semimembranosus and longissimus dorsi muscles. Into variant calling analysis, transcripts of both muscles encoded by genes located in a region between microsatellites SW964 and SW906 (43-135.9 Mbp) in SSC15 were included. In total, 439 transcripts were searched, 2,800 gene variants were identified and 6 mutations with a high effect belonging to the frameshift variants were found (ENSSSCG00000015976, ENSSSCG00000027516, WRN and XIRP2). Moreover, several interesting significant missense variants in PDLIM3, PLCD4 and SARAF genes were detected. These genes are recommended as candidates for meat quality; however they require further investigation in an association study.

Open access

Daniel Polasik, Eva-Maria Kamionka, Mirosław Tyra, Grzegorz Żak and Arkadiusz Terman

Abstract

The aim of this study was to analyze the association of polymorphisms in alpha-ketoglutarate dependent dioxygenase (FTO) and perilipin 2 (PLIN2) genes with carcass and meat quality traits in pigs reared in Poland. The research covered 578 sows that belong to the following breeds: Duroc, Hampshire, Polish Landrace, Pietrain, Puławska and Polish Large White. FTO (FM244720:g.400C>G) and PLIN2 (GU461317:g.98G>A) genes variants were determined by means of PCR-RFLP and ACRS-PCR methods respectively. Association between individual genotypes and analyzed traits was calculated by means of GLM procedure for Polish Landrace, Polish Large White and Puławska breeds separately and for all six breeds together in case of FTO gene. The results showed that FTO variants were associated with weight of loin without backfat and skin (WL), loin eye area (AL) and meat percentage (MP) in Polish Large White (P≤0.05), mean backfat thickness from 5 measurements (BFT) and pH measured 45 min after slaughter in m. longissimus dorsi (pH24 ld) as well as with water holding-capacity (WHC) in Puławska breed (P≤0.01). PLIN2 genotypes, however were correlated with WL and height of the loin eye (HL) in Polish Large White and Puławska (P≤0.05), AL in Polish Large White (P≤0.01) as well as luminosity (L*) in Puławska (P≤0.05) pigs. We observed most consistent relationships of PLIN2 SNP with intramuscular fat content (IMF) and WHC. In 3 analyzed breeds GG genotype was connected with highest values of these traits (P≤0.05).

Open access

Magdalena Szyndler-Nędza, Robert Eckert, Tadeusz Blicharski, Mirosław Tyra and Artur Prokowski

Abstract

One of the approaches to improving performance testing of pigs is to look for mathematical solutions to increase the accuracy of calculations. This is mainly done through improvement of linear regression equations based on current data on performance tested pigs in Poland. The advances in computer technology and the improvements in mathematical analysis have made it possible to use artificial neural networks (ANNs) for prediction of carcass meat percentage in young pigs. The aim of the study was to compare the potential for live estimation of carcass meat percentage in pigs using two computational methods: linear regression equations and ANNs. The experiment used 654 gilts of six breeds, which were subjected to performance testing and slaughter analysis at the Pig Performance Testing Station (SKURTCh). The collected data were used to train ANNs to estimate carcass meat percentage in young pigs. Training was performed using the Levenberg- Marquardt algorithm. Next, meatiness estimated by ANNs was compared with the results obtained using linear modelling. It is concluded that based on the fattening and slaughter performance test results of live pigs, artificial neural networks (SSN23) are significantly more accurate in estimating carcass meat percentage in young pigs compared to the three-variable linear regression model 1. The difference in meatiness estimation between SSN23 and the four-variable linear regression model 2 was statistically non-significant in most of the breeds except Duroc and Pietrain, where the meatiness of young animals was estimated more accurately by the linear regression model.

Open access

Anna Bereta, Mirosław Tyra, Katarzyna Ropka-Molik, Dorota Wojtysiak, Marian Różycki and Robert Eckert

Abstract

The objective of this study was to analyse differences in individual fibre types in the histological profile of the longissimus dorsi muscle and their effect on pork carcass lean content and level of intramuscular fat (IMF) content, which determines palatability of meat and meat products. Analysis showed that the amount of type IIB fibres had a statistically significant (P<0.05) effect on the IMF content of the longissimus dorsi muscle. Animals with more than 70% of type IIB fibres in this muscle were also characterized by larger loin eye area (P<0.01) and loin eye height (P<0.05). Analogous relationships were noted when the analysed group of animals was divided according to the diameter of type IIA fibres. IMF was negatively correlated to the percentage of type IIB fibres (rP= -0.162). Relationships with the other two fibre types were positive (IIA - rP= 0.097; I - rP= 0.187). It was found that increased percentage of type IIB fibres resulted in a slightly greater loin weight (rP= 0.176), higher loin eye height (rP= 0.136), larger loin eye area (rP= 0.265) and higher carcass lean content (rP= 0.204). Likewise, the increase in the number of type IIA and type I fibres decreased these parameters.

Open access

Tomasz Szmatoła, Katarzyna Ropka-Molik, Mirosław Tyra, Katarzyna Piórkowska, Kacper Żukowski, Maria Oczkowicz and Tadeusz Blicharski

Abstract

The aim of this study was to evaluate genetic variability of five pig populations maintained in Poland with the usage of model based clustering method (MCMC approach) on microsatellite data. A high degree of genetic diversity with the values corrected for sample sizes was observed for four breeds: 0.740 for Polish Landrace, 0.697 for Pietrain, 0.692 for Polish Large White and 0.688 for Puławska. Duroc breed, however, was characterized by the lowest genetic diversity (0.589), allelic richness and number of effective alleles. As for Structure software results, each breed was represented by their own cluster while maintaining a possible small admixture of other breeds. The results obtained suggest a moderate gene flow between breeds, especially between Polish Landrace and Polish Large White has occurred. The lowest admixture was presented for Duroc breed, which confirms its high purity. The presented results can be used to study the structure and as a genetic information for the preservation and further genetic improvement of the pig breeds maintained in Poland. It seems also advisable to conduct further studies with a larger number of microsatellites and by analysis of mitochondrial DNA.

Open access

Maria Oczkowicz, Anna Dunkowska, Katarzyna Piórkowska, Aurelia Mucha, Mirosław Tyra and Katarzyna Ropka-Molik

Abstract

Recently, DIO3 gene has been proposed as a candidate gene for litter size in pigs. Moreover, it was shown that polymorphism in this gene is associated with carcass traits. In this study we identified several SNPs within coding sequence of DIO3 by HRM method and performed association study between two polymorphisms and reproductive and carcass traits in pigs bred in Poland. Analysis of 350 pigs of Landrace and Large White breed revealed several significant associations for rs80999359, like period between the second and third parities (2IP)(P<0.0008) in the whole population, period between the third and fourth parities (3IP) (P<0.022), number of piglets born alive (L3NBA) (P<0.0084) and number of piglets at 21 days (L3NB21d) (P<0.0176) at the third parity in Large White as well as period between the second and third parities (2IP) (P<0.0012) in Landrace breed. The second polymorphism (rs80983654) was associated with 1IP (P<0.0218), number of piglets born alive at the fourth parity (L4NBA, P<0.027), number of piglets at 21 day at the fourth litter (L4NB21d, P<0.01), in the whole population, average number of piglets born alive (ANBA, P<0.01250), average number of piglets at 21 day (ANB21d, P<0.009), average interparity period (AIP, P<0.016), age at the first parity (1AP, P<0.003), (1IP, P<0.001, L4NBA, P<0.017, L4NB21d, P<0.005) in Large White breed. In contrast, we have found only few associations between DIO3 polymorphisms and carcass traits. rs80999359 was associated with backfat thickness (p<0.01) while rs80983654 with the weight of ham. Our results suggest that polymorphisms within DIO3 gene may be associated with reproductive traits.