1. The effect of supplementing pig diet with chestnut wood extract or hops on fresh meat and dry-cured productsUrška Tomažin, Martin Škrlep, Maja Prevolnik Povše, Nina Batorek Lukač, Danijel Karolyi, Matjaž Červek, Marjeta Čandek-Potokar, 2020, original scientific article Abstract: Oxidation is one of the major reasons for impaired quality of meat and meat products but can be prevented by the addition of antioxidants. In the present study, the effect of dietary sweet chestnut wood extract and hop cones on the quality and oxidative stability of meat and dry-cured products was investigated. Control pigs (N = 11) were fed a commercial diet (13.1 MJ metabolizable energy, 15.5% crude protein), while the other two experimental groups were supplemented with 3% of sweet chestnut wood extract (Tannin; N = 12) or 0.4% of hop cones (Hops; N = 11). The quality of meat and dry-cured products was evaluated by means of chemical composition, water holding capacity, objective color, and lipid and protein oxidation. No major effects of sweet chestnut wood extract or of hops supplementation were observed, nevertheless, some indications of improved water holding capacity could be attributed to antioxidants supplementation. The color evolution of dry-cured bellies from Tannin and Hops groups of pigs during refrigerated storage was also indicative of an improved oxidative stability.
Keywords: pig meat, meat quality, pig diet, tannin extract, hops, dry-cured products, oxidation, pigs
Published in DKUM: 23.12.2024; Views: 0; Downloads: 2
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2. Effect of immunocastration and housing conditions on pig carcass and meat quality traitsMartin Škrlep, Klavdija Poklukar Žnidaršič, Kevin Kress, Milka Vrecl, Gregor Fazarinc, Nina Batorek Lukač, Ulrike Weiler, Volker Stefanski, Marjeta Čandek-Potokar, 2020, original scientific article Abstract: The present study investigated the effects of immunocastration and housing conditions on carcass, meat, and fat quality traits. Immunocastrates (IC, n = 48), entire (EM, n = 48), and surgical castrates (SC, n = 48) male pigs were reared under three different housing conditions. The conditions were standard (n = 36), enriched (n = 36, twice as much space as standard and additional outdoor access), or standard with repeated social mixing (n = 72). Pigs of the IC group were vaccinated at the age of 12 and 22 wk. The animals were slaughtered in four batches, balanced for sex category and housing, at the age of 27 wk reaching 124.7 ± 1.0 kg. Immunocastration led to increased fat deposition (i.e., thicker subcutaneous fat at different anatomical locations, more leaf fat, fatter belly in IC than EM, P < 0.05) but did not affect muscularity traits. As a result, EM exhibited higher and SC lower (P < 0.05) carcass leanness than IC. Fatty acids composition of either subcutaneous or intramuscular fat (IMF) agreed with general adiposity, that is, IC were intermediate between EM and SC exhibiting the lowest and highest fat saturation (P < 0.05), respectively. Compared to SC, EM exhibited higher (P < 0.05) levels of muscle oxidation and collagen content than SC, with IC taking an intermediate position in the case of the level of peroxidation and collagen content, or closer to SC as regards to oxidation of muscle proteins (i.e., carbonyl groups). Meat quality (including marbling score, cooking loss, subjective color redness, and chroma) of IC was similar to EM, and both differed (P < 0.05) from SC. However, IC and SC had less (P < 0.05) tough meat than EM, consistent with protein oxidation. The effect of housing was less evident. Mixing of pigs resulted in lower (P < 0.05) carcass weight and fatness in all sex categories with lower (P < 0.05) oleic and higher (P < 0.05) arachidonic acid in IMF of EM.
Keywords: carcass traits, entire males, housing, immunocastrates, meat quality, surgical castrates
Published in DKUM: 18.12.2024; Views: 0; Downloads: 2
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3. Adipose tissue gene expression of entire male, immunocastrated and surgically castrated pigsKlavdija Poklukar Žnidaršič, Marjeta Čandek-Potokar, Milka Vrecl, Nina Batorek Lukač, Gregor Fazarinc, Kevin Kress, Volker Stefanski, Martin Škrlep, 2021, original scientific article Abstract: Differences in adipose tissue deposition and properties between pig male sex categories, i.e., entire males (EM), immunocastrates (IC) and surgical castrates (SC) are relatively well-characterized, whereas the underlying molecular mechanisms are still not fully understood. To gain knowledge about the genetic regulation of the differences in adipose tissue deposition, two different approaches were used: RNA-sequencing and candidate gene expression by quantitative PCR. A total of 83 differentially expressed genes were identified between EM and IC, 15 between IC and SC and 48 between EM and SC by RNA-sequencing of the subcutaneous adipose tissue. Comparing EM with IC or SC, upregulated genes related to extracellular matrix dynamics and adipogenesis, and downregulated genes involved in the control of lipid and carbohydrate metabolism were detected. Differential gene expression generally indicated high similarity between IC and SC as opposed to EM, except for several heat shock protein genes that were upregulated in EM and IC compared with SC. The candidate gene expression approach showed that genes involved in lipogenesis were downregulated in EM compared with IC pigs, further confirming RNA-sequencing results.
Keywords: pigs, adipose tissue, entire males, immunocastration, surgical castration, RNA-sequencing, expression
Published in DKUM: 10.10.2024; Views: 0; Downloads: 5
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4. Reduced use of nitrites and phosphates in dry-fermented sausagesMartin Škrlep, Manja Ozmec, Marjeta Čandek-Potokar, 2022, original scientific article Abstract: Given consumer demand for foods with fewer artificial additives, the objective of this study was to investigate the effects of reduced use of nitrites and phosphates on dry-fermented sausage quality. Four sausage formulations were prepared: (1) control (using standard procedure with 0.2% phosphates and 110 mg/kg sodium nitrite) and formulations with (2) 50% less sodium nitrite, (3) 50% less sodium nitrite and sodium ascorbate (225 mg/kg), and (4) with standard nitrite but no phosphates. Weight loss and pH evolution were monitored during processing. The color, physicochemical (including oxidation), rheological, and sensory properties were evaluated on the finished product, as well as mold growth and microbiological status. Compared to control, nitrite reduction was associated with increased surface mold growth, reduced (3.0–4.4%) processing loss, and slightly higher oxidation (1.7 μg/kg more malondialdehyde) but without affecting instrumental color. The simultaneous addition of ascorbate reduced oxidation and improved color stability. The formulation without the phosphates resulted in increased oxidation (3.4 μg/kg more malondialdehyde) and changes in the instrumental color. The observed changes were relatively unimportant, as neither of the tested formulations influenced sensory traits or compromised microbial safety, implying that they can be used in production without any harm or even with some benefits.
Keywords: dry sausages, additives, nitrites, phosphates, ascorbates
Published in DKUM: 04.07.2024; Views: 109; Downloads: 16
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5. Male reproductive organ weight : criteria for detection of androstenone-positive carcasses in immunocastrated and antire male pigsGregor Fazarinc, Nina Batorek Lukač, Martin Škrlep, Klavdija Poklukar Žnidaršič, Alice Broeke, Kevin Kress, Etienne Labussière, Volker Stefanski, Milka Vrecl, Marjeta Čandek-Potokar, 2023, original scientific article Abstract: Immunocastration and rearing of entire males (EMs) are sustainable alternatives to surgical castration. However, these animal carcasses have variable risk of boar taint and should be identified at the slaughter line. We aimed to identify a simple and reliable indicator of androstenone-related boar taint by evaluating pelvic urogenital tract weight as a marker of boar-taint animals at the slaughter line. The pelvic urogenital tract, testes, and accessory sex glands of EMs and immunocastrates (ICs) were collected, dissected, and weighed, before colorimetric measurements of testicular tissue. Additionally, GnRH antibody titers and testosterone, androstenone, and skatole levels were determined. Our results showed that 81.8% of EMs had androstenone levels above the risk threshold (>0.5 µg/g fat; EM/Ahigh subgroup), whereas in ICs, the C/Ahigh subgroup with androstenone >0.5 µg/g fat accounted for only 4.3%. Androstenone levels correlated negatively with GnRH antibody titers and positively with testosterone levels and reproductive organ weights. Identification of ICs with androstenone levels above the threshold (IC/Ahigh subgroup) may be achieved via testes or pelvic urogenital tract weight measurements. However, in EMs, the latter is a more reliable parameter. A principal component analysis based on these variables and hierarchical clustering also distinguished the Ahigh from the Alow subgroup, irrespective of IC/EM. The findings highlight the possible use of pelvic urogenital tract weight along with testes weight as a simple, reliable, and efficient morphometric indicator for identifying androstenone-positive carcasses of different sex categories.
Keywords: boar taint, morphometric indicators, immunocastration, entire males
Published in DKUM: 11.04.2024; Views: 213; Downloads: 13
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6. Immunocastration in adult boars as a model for late-onset hypogonadismNina Batorek Lukač, Kevin Kress, Marjeta Čandek-Potokar, Gregor Fazarinc, Martin Škrlep, Klavdija Poklukar Žnidaršič, Raffael Wesoly, Volker Stefanski, Milka Vrecl, 2022, original scientific article Abstract: Background:
While immunocastration has been studied in male pre-pubertal pigs, data on older, sexually mature animals are limited. To understand the physiological effects of androgen deprivation in the late sexual development phase, we compared mature immunocastrated boars (n = 19; average age = 480 days) to young male immunocastrated pigs (n = 6; average age = 183 days) and young entire males (n = 6; average age = 186 days) as positive and negative controls, respectively.
Objectives:
We hypothesized that the timing of gonadotropin-releasing hormone suppression (early or late sexual development phases) influences the extent of reproductive function inhibition, histological structure of testicular tissue, and expression levels of selected genes related to steroid metabolism.
Materials and methods:
Antibody titer, hormonal status, and histomorphometric analysis of testicular tissue were subjected to principal component analysis followed by hierarchical clustering to evaluate the immunocastration effectiveness in mature boars.
Results:
Hierarchical clustering differentiated mature immunocastrated boars clustered with young immunocastrated pigs from those clustered with entire males. Although all mature immunocastrated boars responded to vaccination, as evidenced by the increased gonadotropin-releasing hormone antibody titers (p < 0.001), decreased serum luteinizing hormone concentrations (p = 0.002), and changes in testicular tissue
vascularization (lighter and less red testicular parenchyma; p ≤ 0.001), the responses were variable. Sharp decreases in testes index (p < 0.001), Leydig cell volume density (p < 0.001), Leydig cell nucleus-to-cytoplasm ratio (p < 0.001), and testosterone concentration (p < 0.001) were observed in mature immunocastrated boars clustered with young immunocastrated pigs compared with those that clustered with entire males. Additionally, mature immunocastrated boars clustered with young immunocastrated pigs showed lower hydroxysteroid 17-beta dehydrogenase 7 expression than entire males (p < 0.05). The young immunocastrated pigs group showed higher folliclestimulating hormone receptors than the entire males and mature immunocastrated boars, lower steroidogenic acute regulatory protein expression levels compared with
entire males, and mature immunocastrated boars clustered with entire males (p < 0.01).
Conclusion:
The two-dose vaccination regime resulted in progressive but variable regression of testicular function in adult (post-pubertal) pigs; however, it was insufficient to induce a complete immunocastration response in all animals.
Keywords: response to immunocastration, pigs, anti-GnRH, morphometry, testicular mRNA expression
Published in DKUM: 16.08.2023; Views: 490; Downloads: 77
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7. Salivary gland adaptation to dietary inclusion of hydrolysable tannins in boarsMaša Mavri, Marjeta Čandek-Potokar, Gregor Fazarinc, Martin Škrlep, Catrin Rutland, Božidar Potočnik, Nina Batorek Lukač, Valentina Kubale, 2022, original scientific article Abstract: The ingestion of hydrolysable tannins as a potential nutrient to reduce boar odor in entire males results in the significant enlargement of parotid glands (parotidomegaly). The objective of this study was to characterize the effects of different levels of hydrolysable tannins in the diet of fattening boars (n = 24) on salivary gland morphology and proline-rich protein (PRP) expression at the histological level. Four treatment groups of pigs (n = 6 per group) were fed either a control (T0) or experimental diet, where the T0 diet was supplemented with 1% (T1), 2% (T2), or 3% (T3) of the hydrolysable tannin-rich extract Farmatan®. After slaughter, the parotid and mandibular glands of the experimental pigs were harvested and dissected for staining using Goldner’s Trichrome method, and immunohistochemical studies with antibodies against PRPs. Morphometric analysis was performed on microtome sections of both salivary glands, to measure the acinar area, the lobular area, the area of the secretory ductal cells, and the sizes of glandular cells and their nuclei. Histological assessment revealed that significant parotidomegaly was only present in the T3 group, based on the presence of larger glandular lobules, acinar areas, and their higher nucleus to cytoplasm ratio. The immunohistochemical method, supported by color intensity measurements, indicated significant increases in basic PRPs (PRB2) in the T3 and acidic PRPs (PRH1/2) in the T1 groups. Tannin upplementation did not affect the histo-morphological properties of the mandibular gland. This study confirms that pigs can adapt to a tannin-rich diet by making structural changes in their parotid salivary gland, indicating its higher functional activity.
Keywords: pigs, dietary supplements, tannins, parotid gland, mandibular gland, immunohistochemistry, histology, proline-rich proteins (PRP), swine
Published in DKUM: 07.07.2023; Views: 506; Downloads: 51
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8. Lipid metabolism, deposition and composition in different metabolic types of pigs : Ph. D. thesisKlavdija Poklukar Žnidaršič, 2022, doctoral dissertation Abstract: Fat deposition contributes importantly to various aspects of pig production such as meat and fat quality. It is influenced by various factors, including genetics (i.e. different breeds) and non-genetic factors (e.g. sex). This study aimed to identify mechanisms underlying these differences. The general objective of the present research was to determine how genetic variants and gene expression networks influence lipid-related traits in different metabolic types of pigs (i.e. among local breeds, between local breeds versus modern pig crossbreed and between entire males versus immunocastrated versus surgically castrated pigs). In the first part of the research, 20 European local pig breeds were phenotypically distributed according to stature, growth performance and fatness traits. Principal component analysis of phenotypic data distinguished between larger and leaner breeds with better growth potential from breeds that were smaller, fatter, and had low growth efficiency. The phenotypic data and genetic variants were used for a genome scan for selection signatures associated with phenotype. Several candidate genes were identified that may have adapted to specific phenotypic traits, such as the ANXA4 and ANTXR1 genes for stature, the TLL1 and KCTD16 genes for growth performance, and the DNMT3A and POMC genes for fatness. Several discovered genes in the genotype-phenotype selection scan were further tested for differential gene expression in adipose tissue between the local Krškopolje and the modern crossbreed. However, no significant differences in expression were found between the studied groups. Additionally, the expression of genes involved in lipid metabolism was further investigated in the same groups to discover possible underlying mechanisms for fatty phenotype in Krškopolje pigs. Genes involved in adipogenesis (i.e. PPARγ) and lipogenesis (i.e. FASN, ACACA) were upregulated in Krškopolje compared to modern crossbreed. These results were further supported by a higher quantity of adipose tissue depots together with a higher desaturation capacity in Krškopolje pigs than in modern crossbreed. However, lipogenic enzyme activities of subcutaneous adipose tissue were lower in Krškopolje than in modern pigs. In the second part of the research, male sex categories were compared at different levels. RNA-sequencing analysis revealed 83 differentially expressed genes between entire males and immunocastrated pigs, 15 between immunocastrated and surgically castrated pigs and 48 between entire males and surgically castrated pigs. Upregulated genes in entire males compared to immunocastrated and surgically castrated pigs were related to extracellular matrix dynamics and adipogenesis, whereas downregulated genes were involved in carbohydrate and lipid metabolism. A candidate gene expression approach using quantitative PCR demonstrated that genes involved in lipogenesis (i.e. FASN, ME1, ACACA) were downregulated in entire males compared to immunocastrated pigs. The obtained transcriptomic results were further associated with the phenotype. It was shown that entire males were the leanest compared to castrated pigs, exhibiting the smallest adipocytes and lobulus surface area in the backfat. In addition, activities of lipogenic enzymes in backfat were similar to surgically castrated pigs, while the immunocastrated pigs had increased activity compared to entire males and surgically castrated pigs. The higher activity of lipogenic enzymes in the backfat of immunocastrated pigs was not consistent with the fatty acid composition, as immunocastrates were still similar to entire males (lower saturated and higher polyunsaturated fatty acid content compared to surgically castrated pigs). To conclude, the present study discovered genetic variants and differentially expressed genes responsible for distinct lipid metabolism in different metabolic types of pigs.
Keywords: prašič, maščobno tkivo, lipidni metabolizem, lokalne pasme, moderni križanci, nekastrirani prašiči, imunokastrirani prašiči, kirurško kastrirani prašiči, selekcijski podpisi povezani s fenotipom, izražanje genov
Published in DKUM: 05.10.2022; Views: 692; Downloads: 6
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9. Zmanjšanje uporabe nitritov in polifosfatov pri predelavi sušenih klobasManja Ozmec, 2021, master's thesis Abstract: Cilj naloge je bil ugotoviti, kakšen je vpliv zmanjšanja količine aditivov (natrijevega nitrita in polifosfatov) ter dodatka natrijevega askorbata na kakovost sušenih klobas. V ta namen so bile oblikovane štiri poskusne skupine. Prva skupina klobas (kontrola) je bila izdelana po že obstoječi recepturi predelovalca (uporaba 0,2 % polifosfatov ter 2,2 % mesarske soli z 0,5 % natrijevega nitrita). Druga skupina klobas je bila narejena s 50 % zmanjšano vsebnostjo natrijevega nitrita, v tretji skupini je bil klobasam poleg 50 % zmanjšane vsebnosti nitritov dodan natrijev askorbat (225 mg/kg). Četrta skupina je bila oblikovana po standardni recepturi, vendar brez polifosfatov. Postopek predelave je trajal 24 dni. Z izjemo vpliva na oksidativno stabilnosti in nekoliko manjših izgub (osuška) ni bilo ugotovljenih pomembnih vplivov zmanjšanja natrijevega nitrita na fizikalno-kemijske lastnosti klobas, prav tako se razlike niso izrazile pri senzoričnih lastnostih, niti pri mikrobiološki sliki. Analize so pokazale, da dodatek natrijevega askorbata v kombinaciji z zmanjšanim dodatkom nitritov pozitivno vpliva na stabilnost barve in antioksidativne lastnosti. V primeru skupine klobas brez dodanih fosfatov ni bilo ugotovljenega pomembnega vpliva pri izgubi (osušek), ne pri reoloških in senzoričnih lastnostih, ugotovljena pa je bila večja oksidacija in vpliv na instrumentalno izmerjeno barvo. Na splošno so bile razlike majhne in slabo opazne, kar je potrdila tudi senzorična analiza.
Keywords: sušena klobasa, nitrit, polifosfati, askorbat
Published in DKUM: 17.09.2021; Views: 804; Downloads: 114
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10. Vpliv mutacije gena ryr1 na lastnosti pršuta pri krškopoljskih prašičihKatarina Horvat, 2020, master's thesis Abstract: V raziskavi smo preučevali vpliv mutacije gena RYR1 na lastnosti kakovosti pršuta. V raziskavo smo vključili stegna 37 kastratov pasme krškopoljski prašič, od tega je bilo 46 % prašičev heterozigotnih nosilcev mutacije (N/n), preostali pa so bili mutacije prosti (N/N). Pred začetkom predelave smo krojena stegna stehtali, izmerili vrednost pH ter parametre barve (L*, a* in b* v mišicah gluteus medius in gluteus profundus). Spremljali smo izgube teže med predelavo, na končnem izdelku pa smo prav tako izmerili barvne parametre (L*, a* in b* v mišicah semimembranosus – SM, biceps femoris – BF in semitendinosus – ST), določili kemijsko sestavo ter reološke lastnosti s pomočjo testov TPA in SR v mišicah BF in SM. Pri genotipu N/n smo ugotovili nekoliko višje izgube med predelavo v primerjavi z genotipom N/N, vendar so bile razlike statistično značilne (P < 0,05) le v fazi soljenja (1,3 odstotne točke). Pri končnem izdelku je bila vsebnost beljakovin višja (P < 0,05) pri genotipu N/n v mišici BF.. Razlike smo opazili tudi pri vsebnosti intramuskularne maščobe, ki je pri nosilcih mutacije nižja (P < 0,05) v mišici BF. Pri vsebnosti vlage, soli, nebeljakovinskega dušika, indeksu proteolize in aktivnosti vode ni bilo statistično značilnih razlik. Pri reoloških značilnostih smo opazili nižji (P < 0,05) relaksacijski indeks in tendenco (P < 0,10) po manjši adhezivnosti, oboje v mišici BF pri genotipu N/n v primerjavi z N/N. Rezultati raziskave so sicer pokazali nekatere razlike v kakovosti in sestavi pršuta med preučevanima genotipoma prašičev, vendar pa so ugotovljene razlike relativno majhne.
Keywords: mutacija gena RYR1, pršut, krškopoljski prašič
Published in DKUM: 20.10.2020; Views: 1365; Downloads: 79
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