Identification of selection signatures can provide a direct insight into the mechanism of artificial selection and allow further disclosure of the candidate genes related to the animals’ phenotypic variation. Domestication and subsequent long-time selection have resulted in extensive phenotypic changes in domestic pigs, involving a number of traits, like behavior, body composition, disease resistance, reproduction and coat color. In this study, based on genotypes obtained from PorcineSNP60 Illumina assay we attempt to detect both diversifying and within-breed selection signatures in 530 pigs belonging to four breeds: Polish Landrace, Puławska, Złotnicka White and Złotnicka Spotted, of which the last three are a subject of conservative breeding and substantially represent the native populations. A two largely complementary statistical methods were used for signatures detection, including: pairwise FST and relative extended haplotype homozygosity (REHH) test. Breed-specific diversifying selection signals included several genes involved in processes connected with fertility, growth and metabolism which are potentially responsible for different phenotypes of the studied breeds. The diversifying selection signals also comprised PPARD gene that was previously found to have a large effect on the shape of the external ear in pigs or two genes encoding neuropeptide Y receptors (Y2 and Y5) involved in fat deposition and stress response which are important features differentiating the studied breeds. REHH statistics allowed detecting several within-breed selection signatures overlapping with genes connected with a range of functions including, among others: metabolic pathways, immune system response or implantation and development of the embryo. The study provides many potential candidate genes with implication for traits selected in the individual breeds and gives strong basis for further studies aiming at identification of sources of variation among the studied pig breeds.

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The aim of the study was to determine technological and consumption quality of some offal components obtained from Pulawska and Polish Landrace fattening pigs, and to analyse the eating quality of the offal products. The study material consisted of 100 fattening pigs: Pulawska (PUL) and 50 Polish Landrace (PL) pigs. The offal components were analysed for physical traits, chemical composition and energy value. Offal products were made from the offal and their physical, chemical and organoleptic parameters were evaluated. Our study showed that breed had a significant effect (p ≤ 0.05) on pH₄₅ of the tongue, heart (PUL > PL), lungs and kidneys (PUL < PL), and on the fat content of the tongue, heart (PUL > PL), liver and kidneys (PUL < PL). A highly significant effect of breed (p ≤ 0.01) was observed for protein content of the lungs, liver (PUL < PL) and kidneys (PUL > PL), for collagen content of the kidneys (PUL < PL) and liver (PUL < PL), and for energy value (p ≤ 0.01) of the heart (PUL > PL) and liver (PUL < PL). Moreover, our results indicate that the organoleptic quality of the evaluated offal products was higher for Pulawska than Polish Landrace pigs, in particular with regard to consistency (p < 0.05) and flavour (p < 0.01) of the liver sausage.

The aim of this study was to evaluate the effect of the level of fat and selected fatty acids found in the milk of sows on the rearing of native breed piglets. Simultaneously, in order to improve the accuracy of the performed analyses, atomic absorption spectrometry was employed in the applied analytic methodology. The experimental animal material comprised 60 sows of the indigenous White Złotnicka breed. Colostrum and milk were collected on the first and 14th days of lactation. In all, 240 samples were collected. The following parameters were determined in the course of the experiment: number and weight of piglets, body weight gains as well as deaths of piglets. A total of 1270 born piglets was subjected to investigations. The performed experiments demonstrated that, with the progress of the lactation period, the content of fat and saturated fatty acids (SFA) turned out to be statistically significant and showed a growing tendency. Fat increased by about 2% and palmitic acid (C16:0) increased most, that is by 5%. Linolic (C18:2) and linolenic (C18:3) acids revealed decreasing trends. Irrespective of the day of lactation, the level of unsaturated fatty acids (UFA) determined in sows' colostrum and milk was higher in comparison with that of SFA, and the UFA to SFA ratio ranged from 1.84% to 1.33%. Proportions of n‐6 to n‐3 fatty acids were determined at the level of about 1.6:1.0 in the colostrum and 1.3:10 in milk. The highest daily body weight gains were recorded in the case of piglets derived from sows with the highest fat level – 294 g, while in the case of stearic acid (C18:0), the smaller its concentration in the colostrum and milk of the experimental sows, the better body weight gains of piglets – 262 g. At the same time, stearic acid (C18:0) was found to exert a statistically significant effect on piglet mortality at the level of P ≤ 0.05. Its highest concentration caused the highest proportion of deaths among piglets ‐ 16.23%. The performed analysis of correlations that occurred between fat, fatty acids and traits associated with piglet rearing confirmed that linolic acid (C18:2; n‐6) was highly significantly correlated with piglets' body weights (r = 0.456**) and was negatively correlated with piglets' deaths (r = −0.312). On the other hand, fat revealed correlation with body weight gains of piglets (r = 0.333*_ and a negative correlation with deaths of piglets (r = −0344*). Recapitulating, the results of the performed experiments revealed that differences in the levels of fat and fatty acids found in sows' colostrum and milk influenced results of piglet rearing. Together with the increase in the content of fat and UFA in sows' colostrum and milk, piglets were characterized by the best body weight, growth rate, as well as by small mortality.