The study aimed at an evaluation of fattening and slaughter performance as well as meat quality of the native Złotnicka Spotted (ZS) pigs and its crosses with Duroc pigs. The experimental material comprised 60 fatteners, divided into three genetic groups of 20 animals (100% ZS, 75% ZS and 50% ZS). The specific character of conservative breeding results in low values of fattening and slaughter performance traits observed in ZS breed. Among the analysed groups, animals with 100% share of ZS genes in their genotype were characterised by low daily weight gains (0.59 kg), considerable backfat thickness (34.96 mm), slight muscle thickness (48.05 mm), and low leanness (41.83%). These parameters were higher in both groups of crosses. Differences between the 100% ZS group and the 50% ZS group were significant for backfat thickness and highly significant for leanness. Acidity and colour parameters analysis showed that meat from all the genetic groups analysed was characterised by a good quality. The highest pH<sub>45 </sub>values were in the 75% ZS group, and meat from this group had the darkest colour (L* = 49.73) and the highest red colour share (a* = 5.11). Statistical analyses showed that ZS breed retained its original traits through the years of breeding. It was confirmed that meat of Złotnicka Spotted breed is characterised by excellent quality. The results indicate that ZS and Duroc breeds crossing improves fattening and slaughter performance, while maintaining good meat quality in their crosses. Results of this study may also be used by breeders. They indicate that crosses of both the breeds kept in extensive breeding may be successfully used in high quality meat production. Pork from such animals may be a raw material for market niche production, such as regional products. The use of meat from crosses in meat processing may improve both quality of the processed products and efficiency of production based on the native Złotnicka Spotted breed.
Uncoupling proteins 2 and 3 (UCP2 and UCP3) as mitochondrial electron transporters are involved in regulation of ATP production and energy dissipation as heat. Energy efficiency plays an important role in physical performance, especially in aerobic fitness. The aim of this study was to examine the association between maximal oxygen uptake and genetic variants of the UCP2 and UCP3 genes. The studies were carried out in a group of 154 men and 85 women, professional athletes representing various sports and fitness levels and students of the University of Physical Education in Poznań. Physiological and molecular procedures were used, i.e. direct measurement of maximum oxygen uptake (VO₂max) and analysis of an insertion/deletion (I/D) polymorphism in the 3'untranslated region of exon 8 of the UCP2 gene and a C>T substitution in exon 5 (Y210Y) of the UCP3 gene. No statistically significant associations were found, only certain trends. Insertion allele (I) of the I/D UCP2 and the T allele of the UCP3 gene were favourable in obtaining higher VO₂max level and might be considered as endurance-related alleles.
The functional and structural integrity of sperm membrane are crucial for the viability of spermatozoa. The commonly used staining test (eosin + nigrosin) for assessing sperm membrane measures only its structural integrity. The hypoosmotic swelling test (HOS) originally developed for human sperm (Jeyendran et al. 1984) has been also applied to several species of domestic animals (bull, pig, horse, dog). The test enables to evaluate the functional status of the sperm membrane. The principle of HOS is based on water transport across the sperm tail membrane under hypoosmotic conditions. It has previously been used to assess the semen quality (Revell and Mrode 1994), to analyse fertilizing capacity (Rota et al. 2000; Perez-Llano et al. 2001) and also to detect viable, immotile cells for ICSI (Intra-cytoplasmic sperm injection) in human (Zeyneloglu et al. 2000). There are two procedures commonly used for sperm capacitation in the pig-sperm washing and incubation before insemination (Nagai 1994). Capacitation involves several changes like removing molecules coating the sperm head membrane, changes in membrane fluidity and intracellular ion concentration (Green and Watson 2001). Thus the membrane integrity as well as functionality may be affected as shown by Harrison (1996). The aim of the present study was to analyse changes in sperm membrane integrity after in vitro capacitation by use of the HOS test.
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