Dorota Wojtysiak

The effect of dietary CLA supplementation on meat and eating quality, and the histochemical profile of the m. longissimus dorsi from stress susceptible fatteners slaughtered at heavier weights.

The influence of adding 2% CLA to the morning feed of a group of 20 crossbred fatteners from 70 to 130 kg on meat quality, eating quality and dietetic value of m. longissimus dorsi was evaluated compared with a group of 20 controls. Addition of 2% CLA in feed did not influence fattening and slaughter results and also some traits of meat and eating quality. The only significant differences were observed in dry matter content, in meat flavour and L(∗), b(∗), and hue angle value. Meat from fatteners from the experimental group had a statistically significant higher content of CLA (P⩽0.01) and lower content of unsaturated fatty acids especially C18: 2, C18: 1 and C20: 4, PUFA fatty acids (P⩽0.01) and a reduction in the ratio of n-6: n-3 PUFA (P⩽0.01). No statistically significant influence of CLA on the content of cholesterol was observed. The results of the current histochemical study showed that dietary CLA supplementation significantly increased both the number and diameter of white fibres, and correspondingly reduced the number and diameter of red fibres. The percentage and diameter of intermediate fibres was unaffected by CLA.

Carcass quality, physico-chemical parameters, muscle fibre traits and myosin heavy chain composition of m. longissimus lumborum from Puławska and Polish Large White pigs.

In 54 Puławska pigs and 60 Polish Large White pigs (PLW), slaughtered at 30 and 100 kg body weight, carcass and meat quality of m. longissimus lumborum were studied. Analysis revealed that in both examined body weight groups, hot carcass weight, carcass yield percentage, meat content, and weight of ham and carcass ham percentage were significantly lower and backfat thickness higher for Puławska pigs compared to PLW pigs, while PLW pigs exhibited significantly longer carcasses, greater loin eye area, and, in the case of lighter pigs, smaller proportion of loin in the carcass. Muscles of Puławska pigs, in the lighter group, had higher IMF content and a* value, while in the heavier group they exhibited higher pH(45), pH(24) and a* values, lower L*, drip loss, WHC, and thermal loss compared with PLW pigs. PLW pigs had higher WB and hardness values and more glycolytic muscles characterised by higher TNF.

Effect of feed restriction on performance, carcass composition and physicochemical properties of the M. pectoralis superficialis of broiler chickens.

Abstract The aim of this study was to evaluate the effect of feed restriction on carcass composition, breast meat quality and microstructure of the m. pectoralis superficialis of broiler chickens. A total of 315 day-old female broilers (Ross 308) were randomly assigned to 3 groups of 105 birds each in 3 pen replicates. They were fed ad libitum as the control (I), and restricted for 6 h/day (from 08:00 to 14:00 h) as group II (3 and 4 weeks of age) and group III from 4 to 5 weeks of age. On day 42 of growth, 6 broilers with average body weight were chosen from each group for slaughter to analyse dressing percentage, carcass quality, physicochemical properties of breast muscles, including pH, colour (CIE L*a*b*), expressible juice, drip loss, thawing loss, cooking loss, Warner-Bratzler shear force, texture (TPA) and chemical composition, as well as histochemical profile of the m. pectoralis superficialis. Temporary feed restriction did not significantly alter the final body weight, dressing percentage and the proportion of breast and leg muscles, but increased the proportion of abdominal fat. No differences were found in the microstructure of the m. pectoralis superficialis of restricted and ad libitum fed chickens. Restricted feeding had an effect on water holding capacity and tenderness of breast muscles, and a non-significant effect on texture parameters and chemical composition. Restricted feeding of chickens changed their meat quality to a greater extent when applied from 3 to 4 weeks compared to analogous procedures introduced from 4 to 5 weeks of age.

Effect of weak electromagnetic field on cardiac work, concentration of thyroid hormones and blood aminotransferase level in the chick embryo

The aim of the study was to determine the effect of alternating electromagnetic field (EMF; 50 Hz frequency, 50 and 100 μT induction) on cardiac work of the chick embryo. Eggs from the experimental groups were exposed to EMF throughout incubation. During the experiment, heart rate (ballistocardiographic method), thyroxine (T4) and triiodothyronine (T3) concentrations, heart weight, ventricle wall thickness, and levels of alanine aminotransferase (ALT) and aspartate aminotransferase (AST) were determined. The results show, for the first time, that the exposure of chick embryos to EMF augments the heart rate, especially from 17 days of incubation. The increased heart rate in the embryos exposed to EMF was associated with considerable increases in plasma T4 and T3 concentrations, which were recorded during the final stage of embryogenesis. The significant effect of the 100-μT field on heart weight and blood AST levels in the embryos suggests that EMF has a direct effect on the physiological function of cardiac muscle.

Histological profile of the longissimus dorsi muscle in Polish large white and Polish landrace pigs and its effect on loin parameters and intramuscular fat content

Abstract The objective of this study was to analyse differences in individual fibre types in the histological profile of the longissimus dorsi muscle and their effect on pork carcass lean content and level of intramuscular fat (IMF) content, which determines palatability of meat and meat products. Analysis showed that the amount of type IIB fibres had a statistically significant (P<0.05) effect on the IMF content of the longissimus dorsi muscle. Animals with more than 70% of type IIB fibres in this muscle were also characterized by larger loin eye area (P<0.01) and loin eye height (P<0.05). Analogous relationships were noted when the analysed group of animals was divided according to the diameter of type IIA fibres. IMF was negatively correlated to the percentage of type IIB fibres (rP= -0.162). Relationships with the other two fibre types were positive (IIA - rP= 0.097; I - rP= 0.187). It was found that increased percentage of type IIB fibres resulted in a slightly greater loin weight (rP= 0.176), higher loin eye height (rP= 0.136), larger loin eye area (rP= 0.265) and higher carcass lean content (rP= 0.204). Likewise, the increase in the number of type IIA and type I fibres decreased these parameters.

Visualization of porcine eye anatomy by X-ray microtomography

Abstract The aim of our study is to obtain, as accurately as possible, porcine ocular tissue visualization using microtomography (micro‐CT) method. We propose image contrast enhancement by different staining procedures with combination of micro‐CT scanning. Porcine eye globes were investigated with Bruker‐SkyScan 1172 micro‐CT. We used 4F1G and Bouins as sample fixation solutions and tincture of iodine, 100% Lugol, phosphotungstic acid and 1% osmium tetroxide solutions for staining. Quantitative and qualitative analysis was performed based on micro‐CT reconstruction images histograms and 3D volume rendering models of investigated samples. This investigation showed that staining methods improved micro‐CT image quality in case of ocular anatomy visualization. Characteristic profiles of the grey level distributions and quality of the cross‐section and 3D volume rendering images confirmed the staining effect. Most significant contrast enhancement was obtained after 96 h staining in osmium tetroxide and Lugol solutions. The images of eye anatomical structures were characterized: cornea, lens, iris, ciliary body, vitreous, retina, choroid and sclera, vasculature and optic nerve. Staining of porcine eye globes used in this work leads to quality improvement of the micro‐CT imaging. The most contrast images were obtained for Lugol and osmium tetroxide solutions. Different affinity of staining solutions to eye anatomical structures has been observed in the obtained images. Osmium tetroxide provides sharper image of conjunctiva, sclera, choroid, retina, iris and ciliary body structure. Lugol staining leads to more accurate vessels, cornea and optic nerve imagining. HighlightsApplication of micro‐CT for porcine eye globe anatomy visualization.Investigation of staining procedure for most accurate contrast enhancement in micro‐CT eye images.Eye globe anatomical details identification based on 3D volume rendering models of the samples.

Study of cholesterol and vitamin E levels in broiler meat from different feeding regimens by TOF-SIMS

The quality of chicken meat, which is one of the most widely consumed meats in the world, has been the subject of research and studies for many years. There are several ways to improve the quality of this type of meat, including changing the concentrations of individual molecular components. Such important components of meat are inter alia, cholesterol, vitamin E, and some fatty acids such as ω-3 and ω-6. Manipulation of ingredient levels may be achieved by enriching chicken feed with elements of different types such as vegetable oils, garlic, or selenium. Thus far, various biochemical and biophysical methods have been used to study quality of different meat types, especially broiler meat. Here, the authors demonstrate the use of high-resolution time-of-flight secondary ion mass spectrometry (TOF-SIMS) mass spectrometry to assess how variations in animal nutrition affect concentrations of specific lipids in the meat, such as cholesterol and vitamin E. In the presented experiment, there were four different dietary treatments. Feed for animals in the first group was supplemented with soy oil in 50%, the second groups feed was supplemented with linseed oil in 50%, a combination of these two oils in the proportion of 44%:56% was used for the third group, and in the reference group, animals were fed with beef tallow. From each group, four individuals were selected for further analysis. Positive and negative ion mass spectra were generated from the pectoralis superficialis muscle tissue of the left carcass side of each one animal. Using TOF-SIMS with a bismuth cluster ion source (Bi3 (+)), and based on characteristic peaks for cholesterol in the positive mode and vitamin E in the negative mode, the authors have illustrated the relationship of these lipids levels to the various feeding regimens. Simultaneously, the authors characterized the varying dependences on the concentrations of measured lipids in fat and muscle fibers. The cholesterol concentration in muscle fibers was the lowest in the group fed with soybean oil and the highest in reference group IV (tallow feed). In the fatty region, the highest level of cholesterol was found in the third group. The highest concentrations of vitamin E were found in the fibers of the first group and the fat region of the second group. The obtained results show that SIMS imaging is a useful approach for assessing changes in lipid concentrations in the meat tissue from animals on different diets and provides a foundation for future research.

Effect of breed on microstructure and tenderness of porcine semimembranosus muscle.

Abstract The objective of the study was to analyse the effect of breed on characteristics of muscle fibres, parameters of intramuscular connective tissue, collagen content, intramuscular fat (IMF) content and tenderness of semimembranosus muscle in pigs. The study was conducted with 16 Złotnicka Spotted (ZS) and 23 Polish Landrace (PL) fattening pigs slaughtered at 210 days of age. The current study showed that compared to the PL breed, the semimembranosus muscle from the local breed of ZS pigs was characterized by a greater percentage of type I fibres, a smaller percentage of type IIB fibres and a smaller diameter of all the three muscle fibre types analysed, while the muscles of PL pigs had significantly thinner endomysium and perimysium and a more compact arrangement of collagen fibres, with a significantly lower percentage of collagen in the muscle and a lower content of total and soluble collagen compared to the muscles of ZS pigs. Furthermore, meat from ZS pigs was more tender (lower shear force value) and had a significantly higher IMF content compared to meat from PL pigs.

Effect of breed and age on histopathological changes in pig m. semimembranosus

Effect of Breed and Age on Histopathological Changes in Pig M. Semimembranosus The aim of the study was to determine the type and extent of histopathological changes in m. semimembranosus of Polish Landrace (PL), Polish Large White (PLW), Duroc, Pietrain, and Puławska pigs at 60, 90, 120, 150, 180 and 210 days of age. Changes in fibre size (atrophy, hypertrophy - giant fibres), changes in fibre shape (angular fibres), degenerative lesions (necrosis with phagocytosis) and connective tissue hypertrophy were evaluated. The presence of giant fibres was the only histopathological change observed in all age groups of PL, PLW, Duroc and Pietrain pigs, with the percentage of pigs with this type of pathology and the frequency of giant, atrophic and angular fibres increasing significantly with age. In Puławska pigs, giant fibres were only found in the oldest pigs aged 210 days. In these animals, giant fibres as well as atrophic fibres (at 180 and 210 days of age) and angular fibres (at 120, 150, 180 and 210 days of age) occurred in the smallest number of animals and were least extensive. Meanwhile, Pietrain pigs were characterized by a greater number of animals, a significantly greater proportion of giant fibres in all analysed age groups, and a greater proportion of atrophic fibres at 180 and 210 days of age compared to the other pig breeds under analysis. For connective tissue hypertrophy and necrosis with phagocytosis, the changes were not extensive. It is concluded that both the advancing age of the animals and selection of the pigs for increased leanness significantly increases the incidence of histopathological changes in muscle tissue, which may directly translate into pork quality. Wpływ rasy i wieku na zmiany histopatologiczne w m. semimembranosus świń Celem pracy było określenie rodzaju i rozległości zmian histopatologicznych w m. semimembranosus świń ras pbz, wbp, Duroc, Pietrain oraz puławskiej ubijanych w: 60. 90., 120., 150., 180. i 210. dniu życia. Analizowano zmiany wielkości włókien mięśniowych (atrofia, hipertrofia - włókna olbrzymie), zmiany ich kształtu (włókna angularne), zmiany degeneracyjne (martwica z fagocytozą) oraz przerost tkanki łącznej. Stwierdzono, że jedyną zmianą histopatologiczną obserwowaną we wszystkich grupach wiekowych świń ras PL, PLW, Duroc oraz Pietrain była obecność włókien olbrzymich, przy czym zarówno procent świń wykazujących ten rodzaj patologii, jak i frekwencja włókien olbrzymich, a także włókien atroficznych i angularnych wzrastała istotnie wraz z wiekiem. U świń rasy puławskiej włókna olbrzymie wykazano wyłącznie u najstarszych świń w 210. dniu życia. U nich też włókna olbrzymie, a także włókna atroficzne (w 180. i 210. dniu życia) oraz angularne (w 120., 150., 180., i 210. dniu życia) występowały u najmniejszej liczby osobników i charakteryzowały się istotnie najmniejszą rozległością. Z kolei świnie rasy Pietrain charakteryzowały się większą liczbą osobników, a także istotnie większym udziałem włókien olbrzymich we wszystkich analizowanych grupach wiekowych, jak również większą proporcją włókien atroficznych w 180. i 210. dniu życia w porównaniu z pozostałymi analizowanymi rasami świń. W przypadku przerostu tkanki łącznej, jak i martwicy z fagocytozą obserwowane w niniejszej pracy zmiany miały niewielki zasięg. Podsumowując, można stwierdzić, iż zarówno wydłużający się wiek zwierząt, jak i selekcja świń w kierunku zwiększenia mięsności wpływają istotnie na wzrost frekwencji występowania zmian histopatologicznych w tkance mięśniowej, co może mieć bezpośrednie przełożenie na jakość mięsa wieprzowego.

Transcriptomic Changes in Broiler Chicken Hypothalamus during Growth and Development

The hypothalamus plays an overarching role that is reflected in the physiological processes observed in the entire organism. The hypothalamus regulates selected metabolic processes and activities of the autonomic nervous system. The avian hypothalamus due to the structural complexity is not well described and has a slightly different function than the mammalian hypothalamus that is the subject of numerous studies. The present study evaluated activities of hypothalamic genes in fast-growing chickens during development (at the 1st day and 3rd and 6th weeks after hatching). The hypothalamic transcriptomes for 3- and 6-week-old cockerels were analysed using an RNA sequencing method in next-generation sequencing (NGS) technology. The differentially expressed gene analysis was conducted using DESeq2 software. In younger 22-day-old cockerels, 389 genes showed higher expression (fold change > 1.5) than that in 45-day-old birds. These genes played a role in several biological processes because they encoded proteins involved in integrin signalling, regulation of hormone levels, camera-type eye development, and blood vessel development. Moreover, surprisingly in the hypothalamus of 3-week-old cockerels, transcripts were identified for proteins involved in both anorexigenic (POMC, NMU) and orexigenic (PMCH, ALDH1A1, LPL, and GHRH) pathways. The RNA-seq results were confirmed by qPCR methods. In summary, the intensive growth of 3-week-old chickens was reflected in hypothalamic activities because the genes associated with the somatotropin axis and regulation of satiety centre showed increased expression.