The aim of the study was to determine the quality and nutritional value of meat originating from pigs of polish native pure breeds -the puławska and Złotnicka spotted as well as the commercial four-breed crossbreds f1 (large white × polish landrace) × f1 (duroc × pietrain). physicochemical properties of meat were evaluated, such as acidity, water holding capacity, tenderness, and color parameters. in addition, functional properties of meat were determined: nutritional value, mineral content and fatty acid profile. the dietetic indices of meat were also determined. the smallest acidity of muscle tissue was characteristic of the meat of the puławska breed and the smallest meat drip loss was found in both native breeds (p≤0.01). this can confirm their greater technological suitability. the most tender was meat obtained from pigs of the puławska breed (36.07 n/cm 2 ). the darker color was characteristic of the pig meat of the Złotnicka spotted breed (l* = 49.19) (p≤0.01). meat of all three groups of the tested pigs had the quality characteristics related to normal meat. the highest content of protein was found in the Złotnicka spotted meat (25.23%) at optimum fat content (2.25%). the high content of ash (1.63%) recorded in the Złotnicka spotted meat meant higher content of macro and microelements, especially iron and zinc, as compared to meat of the four-breed crossbreds (p≤0.01). the highest amount of monounsaturated fatty acids (52.72%) was recorded in porcine meat of the puławska breed, while content of polyunsaturated fatty acids was the highest in meat of the four-breed crossbreds (16.77% vs. 9.32% and 15.19%) (p≤0.01). no differences were found between the groups tested for atherogenic index. in terms of most physicochemical and functional characteristics, meat of native pig breeds was superior to the meat of commercial pigs from mass-production. key words: pigs, native breeds, meat quality, nutritional value *This study was funded from statutory activity.

The aim of the study was to evaluate the relations between genotype effects at porcine loci MYF3, MYF4, MYF5 and MYF6 on meat quality traits in pigs of the CC genotype at the RYR1 locus. Meat traits were analysed in longissimus lumborum muscle in 98 pigs (75 of PLW´PL and 25 [PLW´PL]´Pietrain crosses). The determined meat characteristics covered the pH 1 and pH u records, visual assessment of colour and exudation on fresh meat samples, water holding capacity, drip loss, spectrophotometric measurements of dominant wavelength, colour saturation and lightness, L, a*, b* values according to the CIE system, basic chemical constituents (water, protein, intramuscular fat and ash) and soluble protein fraction in meat. The distribution of animals within particular MyoD genotypes only in the MYF4 and MYF5 genotypes were spread uniformly. The gene effects at particular MyoD loci on studied meat traits were significant. The most pronounced effect on meat quality was exerted by the myogenin gene (MYF4). Individuals of the BB genotype in respect to the MYF4 locus showed a better water holding capacity (P<0.01), lower drip loss (P<0.05), darker colour score (P<0.01) and better wateriness score (P<0.01), darker and more desirable colour characteristic (P<0.01) than pigs with the AA genotype, whereas AB genotype animals had intermediate values. In respect to meat protein solubility the AA genotype pigs had a significantly lower level of soluble protein in meat than AB and BB (P<0.01). On basis of the present study it may be inferred that mutations in coding and the non-coding regions of MyoD genes exert significant effects on muscle traits related to oxidative metabolism, as well as related to glycolysis and contractile muscle properties, and thereby on meat quality.

The paper presents the results of a study on the relationship between acidification (pH) and standard quality characteristics of the meat of Polish Large White × Polish Landrace pig crossbreds. The meat for the study was obtained from 184 F1 Polish Large White × Polish Landrace fatteners from a herd free of the stress-sensitivity gene. The obtained results were analysed in groups formed according to the meat’s measured pH45 values (≤ 6.3; 6.3–6.7; > 6.7) and pHu values (≤ 5.3; 5.3–5.6; > 5.6). Increasing measured pH45 values were paralleled by greater water-holding capacity and plasticity, lower drip loss, darker colour L* as assessed visually and with equipment, and greater content of muscle pigments (P < 0.01) of the evaluated meat. Higher pHu values had a more pronounced impact on WHC, free drip loss, tenderness, water content, and colour parameters: a*, b*, chroma C* (P < 0.01), and hue angle ho (P < 0.05). The obtained simple correlations between pH45 and pHu acidity and meat-quality characteristics indicate that the measured pH45 value was correlated more closely than ultimate acidification (P < 0.01) with visually assessed colour intensity, tactilely assessed meat hardness, colour lightness L* (P < 0.01), hue angle ho (P < 0.05), and muscle pigment content. On the other hand, pHu was more strongly correlated with water-holding capacity, drip loss, meat tenderness as well as water and protein content (P < 0.01).