The aim of the paper was to investigate the impact of feeding pigs with different levels of conjugated linoleic acid or sunflower oil on fatty acid profile of Longissimus dorsi muscle. The subjects of research were 60 crossbred gilts divided into 6 groups, fed with different levels of conjugated linoleic acid (CLA) or sunflower oil (SFO) (0.5; 1.0 and 2.0 %, respectively). All fatteners were kept and fed under standardized conditions. Animals were slaughtered at 95 kg of body weight. Fatty acid profile was determined in samples of Longissimus dorsi muscle from each animal. Gas chromatography was used (in the research). The significance of differences between groups was verified by Duncan's test. In the present study the addition of conjugated linoleic acid or sunflower oil did not impact the composition and amounts of saturated or unsaturated fatty acids in Longissimus dorsi muscle. Keywords

Backfat Fatty Acid Profile of Crossbred Pigs Fed a Diet Supplemented with Conjugated Linoleic acid or Sunflower OilThe aim of the study was to investigate the impact of feeding pigs with different levels of conjugated linoleic acid (CLA) or sunflower oil (SFO) on the backfat fatty acid profile. The subjects of research were 60 crossbred gilts divided into 6 groups, which were fed different levels of conjugated linoleic acid or sunflower oil (0.5, 1.0 and 2.0%, respectively). All fatteners were kept and fed under standardized conditions. Animals were slaughtered at 95 kg of body weight. Fatty acid profile was determined in samples of backfat from each animal using gas chromatography. The significance of differences between groups was verified by Duncan's test. In the present study, a beneficial effect of adding CLA was that it reduced saturated fatty acids and increased unsaturated fatty acids in the adipose tissue (backfat) of pigs as compared to fatteners receiving SFO. The amount of monounsaturated fatty acids in the backfat decreased with increasing amounts of CLA or SFO. Modifying the fatty acid profile of pig backfat through addition of CLA or SFO would be beneficial to the health of consumers because relatively large amounts of fat pork, including backfat, are added to the sausages.

The behaviour of 31 to 43 pregnant sows housed in one pen was observed during 5 diurnal periods (the number of sows depending on the timing of parturition). On the basis of these behavioural observations the sows were distributed into 5 social ranks: dominants, subdominants, subordinated, selfpossessed and marginals. The reproductive traits studied were: number of live-born piglets, number of piglets alive at 21 days, and litter weight at 21 days. Reproductive performance evaluated in this way did not show any distinct differences according to the social ranks of sows. The average number of piglets born alive varied from 10.8 in selfpossessed to 12.7 in the two extreme ranks: dominants and marginals. The number of piglets alive at 21 days varied from 10.5 in self-possessed to 12.3 in marginals. Litter weight at 21 days varied from 58.0 kg in subdominants to 59.7 kg in marginals. It is suggested that the electronic feeding system is advantageous for the housing of pregnant sows. This feeding system enables maintenance of pregnant sows in one group and permits undisturbed and individual feed consumption irrespective of sows social rank.

The aim of presented paper was analysis of the performance test results of young pure breed boars coming from The Bydgoszcz Breeding Region (located in Poland in Kujawy-Pomorze Province). The research covered the results concerning 4190 young boars of following breeds: Polish Large White, Polish Landrace, Hampshire, Duroc and Pietrain. Young pure breed boars were performance tested in 2009 and 2010 in The Bydgoszcz Breeding Region according to the actual methodology. Among young pure breed boars performance tested in The Bydgoszcz Breeding Region in tested years animals of Hampshire breed had the higher growth rate. The pigs of Pietrain breed had the highest meat content. Regarding to the most important parameter of performance test, i.e. selection index in analyzed years 2009 and 2010 the best results had young boars of Hampshire then Pietrain, Duroc, PLW and PL.Keywords: daily gain of body weight, meat content, performance test, selection index, young pure breed boars Abstrakt Celem prezentowanej pracy była analiza wyników oceny przyŜyciowej knurków czysto rasowych pochodzących z bydgoskiego okręgu hodowlanego (zlokalizowanego w Polsce, w woj. kujawsko-pomorskim). Badaniami objęto wyniki dotyczące 4190 knurków ras: wielkiej białej polskiej, polskiej białej zwisłouchej, hampshire, duroc i pietrain. Knurki zostały poddane ocenie przyŜyciowej w 2009 i 2010 r. w bydgoskim okręgu hodowlanym według aktualnej metodyki. Spośród knurków czysto rasowych ocenionych przyŜyciowo w bydgoskim okręgu hodowlanym w badanych latach zwierzęta rasy hampshire odznaczały się największym tempem wzrostu. Świnie rasy pietrain charakteryzowały się największą mięsnością. Pod względem najwaŜniejszego parametru oceny przyŜyciowej, tj. indeksu selekcyjnego w analizowanych latach 2009 i 2010 najlepsze wyniki uzyskały knurki rasy hampshire, następnie pietrain, duroc, wbp i pbz. 12Journal of Central European Agriculture, 2016, 17(1), p.12-24 DOI: 10.5513/JCEA01/17.1.1662Słowa kluczowe: indeks selekcyjny, knurki czysto rasowe, mięsność, ocena przyŜyciowa, przyrost dobowy masy ciała Streszczenie szczegółowe Znaczący postęp wartości hodowlanej trzody chlewnej w zakresie uŜytkowości tucznej i rzeźnej nastąpił na skutek prac hodowlanych prowadzonych na podstawie oceny przyŜyciowej. Wyniki tej oceny są jednym z podstawowych kryteriów w pracach selekcyjnych nad trzodą chlewną przy wyborze zwierząt do stad hodowlanych i produkcyjnych. Bydgoski okręg hodowlany zlokalizowany jest w woj. kujawsko-pomorskim i w produkcji świń zajmuje czołowe miejsce w Polsce, a produkowane na jego terenie knurki i loszki oddziałują na poziom uŜytkowości tego gatunku zwierząt w kraju.