Goran Kušec

Differentiation of pork longissimus dorsi muscle regarding the variation in water holding capacity and correlated traits

Abstract This study was performed on 87 randomly selected carcasses of castrated pigs, slaughtered at approximately 100 kg live weight in 2 abattoirs from east Croatia. Important meat quality traits were measured on the samples of musculus longissimus dorsi: initial and ultimate pH values (pH45 and pH24), meat colour and drip loss. Samples were further differentiated into 5 groups on the base of meat quality conditions. Results show that 14.66%, 32%, 40%, 10.67% and 2.66% of the longissimus dorsi muscles belonged to PSE, RSE, RFN, PFN and DFD conditions respectively. The highest correlations were observed between ultimate pH value, drip loss and meat colour. Interpolated threshold value for ultimate pH was 5.69. It is suggested to verify the values used for differentiation of meat according to quality on a larger sample.

Application of growth functions in the prediction of live weight of domestic animals

We consider several most frequently used growth functions with the aim of predicting live weight of domestic animals. Special attention is paid to the possibility of estimating well the saturation level of animal weight and defining life cycle phases based on animal weight. Parameters of the growth function are most often estimated on the basis of measurement data by applying the least squares (LS) principle. These nonlinear optimization problems very often refer to a numerically very demanding and unstable process. In practice, it is also possible that among the data there might appear several measurement errors or poor measurement samples. Such data might lead not only to unreliable, but very often to wrong conclusions. The least absolute deviations (LAD) principle can be successfully applied for the purpose of detecting and minorizing the effect of such data. On the other hand, by using known properties of LAD-approximation it is possible to significantly simplify the minimizing functional, by which parameters of the growth function are estimated. Implementation of two such possibilities is shown in terms of methodology.

Differences in carcass traits, meat quality and chemical composition between the pigs of different CAST genotype

The study was carried out on 89 Pig Improvement Co. (PIC) pig carcasses, with the aim to investigate the differences between three CAST loci in carcass and meat-quality traits, as well as chemical composition of longissimus dorsi (LD) muscle. The differences among genotypes at CAST/HinfI locus were significant in all carcass traits measured, where AB genotype exhibited preferable values in carcass lengths, ham length, muscle thickness, loin eye area, fat thickness and fat area. Among meat-quality traits analysed, genotypes at CAST/HinfI locus differed in pH45 in SM muscle, both pH24 in semimembranosus (SM) and LD muscles, as well as luminosity; genotypes at CAST/MspI differed in pH24 and EC24 measured at LD muscle and in red colour intensity, level of yellowness and hue angle; while genotypes at CAST/RsaI differed in pH45 and EC45 in SM muscle, pH24 in LD muscle, paleness and redness, as well as in shear force and calpain activity. EF genotype at this locus exhibited the highest pH values and the lowest CIE L*, with more pronounced red colour, but also highest shear force and lowest calpain activity values. Furthermore, significant differences in chemical composition of LD muscle were found only among genotypes at CAST/RsaI loci, where FF genotype had the lowest intramuscular fat and the highest relative share of protein.

The impact of frozen storage duration on physical, chemical and microbiological properties of pork

The aim of the present study was to evaluate the effect of frozen storage duration (3, 6, 9, 12, 15, 18 months) on physical, chemical and microbial properties of pork in three cuts (loin, ham, and belly rib). During frozen storage, significant alterations in physical and chemical parameters were observed through the increase of the total exudate, pH and lightness (L*), and a decrease of shear force and yellowness (b*). Water content in ham samples decreased, while protein content increased. The lipid oxidation (TBA) values in loin and ham samples increased for up to fifteen months of frozen storage, after which they decreased. The proportion of saturated fatty acids in frozen samples was significantly higher than in fresh meat. The total amount of Enterobacteriaceae, S. aureus and Pseudomonas spp. decreased during frozen storage, indicating that freezing may reduce the number of bacteria found in meat. Frozen pork microflora did not change after eighteen months of storage.

Análise genética de raças suínas autóctones da Croácia através do uso de microssatélites como marcadores

Black Slavonian pig (BS) and Turopolje pig (TP) are two Croatian autochthonous pig breeds. At the beginning of this century attempts were made to preserve and re-establish them, which included also employment of the genetic methods for studying genetic characteristics of both breeds. The number of Black Slavonian breed sows was increased from 237 in 2001 to 1305 last year, while the number of Turopolje breed sows rose from 45 to 132 in the same period. A set of 18 microsatellite markers was used to genotype 20 BS pigs, 20 TP pigs and 20 wild boars. The basic statistical analysis included number of samples, number of alleles for each locus, expected and observed heterozygosity, FIS and their statistical significance FISsign. In observed populations, a relatively high variety of loci was present. Average heterozygosity was between 0.35 and 0.64. The average fixation index (FST) was 0.24. Multilocus FST values indicated that around 24% of the total genetic variation was explained by population differences, with the remaining 78% corresponding to differences among individuals within population. Genetic distances between populations were made with PCA method and it was noticed that studied populations are clearly defined. The analysis of population structure indicates no admixture among analysed breeds. However, some substructuring in the Black Slavonian pig population was observed. Results confirmed usefulness of microsatellites for studying genetic diversity among Croatian autochthonous pig breeds, but for obtaining more accurate results, a study involving larger number of animals and other related breeds would be required.

Genetic diversity of autochthonous pig breeds analyzed by microsatellite markers and mitochondrial DNA D-loop sequence polymorphism

Abstract The evaluation of the genetic structure of autochthonous pig breeds is very important for conservation of local pig breeds and preservation of diversity. In this study, 18 microsatellite loci were used to detect genetic relationship between autochthonous pig breeds [Black Slavonian (BS), Turopolje pig (TP), and Croatian wild boar] and to determine phylogenetic relationship among Croatian autochthonous pig breeds and certain Asian and European pigs using the mitochondrial DNA (mtDNA) D-loop sequence polymorphism. Relatively high degree of genetic variation was found between the observed populations. The analysis of mtDNA showed that haplotypes of the studied pig populations are different from the other European and Chinese haplotypes. BS pigs showed some similarities with Mangalitsa and Duroc breeds. The genetic distances of TP can be explained by high degree of inbreeding during the past century. Despite the European origin of Croatian pig breeds with some impact of Chinese breeds in the past, the results of present study show that genetic diversity is still pronounced within investigated breeds. Furthermore, the genetic diversity is even more pronounced between Croatian breeds and other European and Chinese pig breeds. Thus, conservation of Croatian pig breeds will contribute to overall genetic diversity preservation of pig breeds.

Efficiency of PCR-RFLP and species specific PCR in identification of meat origin in dry sausages

The purpose of the investigation was the identification of chicken, beef and sheep meat in pork sausages using PCR-RFLP and PCR with species specific primers. Six dry fermented pork sausages were produced by adding beef, sheep and chicken meat to each in the amount of 1% and 5%. DNA was extracted from five locations of each sausage and PCR-RFLP together with PCR using species specific primers was performed. PCR-RFLP analysis was successful only for chicken meat, while species specific PCR was effective for identification of chicken, beef and sheep meat in all ratios and at all locations. The results of our study showed that in investigated products discovering of adulteration using PCR-RFLP is suitable only for chicken meat, while for detection of beef and sheep meat use of species specific oligonucleotides is more adequate.

Carcass leanness of pigs in Croatia estimated by EU referent method

Abstract The experiment was performed on 146 swine carcasses slaughtered at several Croatian slaughterhouses, selected according to backfat measures obtained by method for lean percentage prediction approved in Croatia (NN 40/2007). One day after slaughter left sides of the carcasses were dissected according to EU reference method (Commission Regulation No 3127/94, Walstra and Merkus, 1996). The dissected lean percentage was assessed using the formulae prescribed in EU Regulation from 1994 (Commission Regulation (EC) No 3127/94) and 2006 (Commission Regulation (EC) No 1197/2006). There were statistically significant differences between the lean shares estimated by Croatian prediction routine and assessed by both previous and current European regulation (p<0.01). When pig carcasses were classified by SEUROP system based on the lean percentage established by three mentioned methods, the distribution into quality classes was markedly different. It was concluded that because of substantial difference between the procedures for estimation of dissected lean percentage (51.00 vs 56.32%) further investigations on that matter are suggested. Croatian lean meat prediction equation significantly differed from dissected lean expressed by both European assessment methods and needs to be adjusted.