1. 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, izvirni znanstveni članek Opis: 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.
Ključne besede: pigs, adipose tissue, entire males, immunocastration, surgical castration, RNA-sequencing, expression
Objavljeno v DKUM: 10.10.2024; Ogledov: 0; Prenosov: 0
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2. Reduced use of nitrites and phosphates in dry-fermented sausagesMartin Škrlep, Manja Ozmec, Marjeta Čandek-Potokar, 2022, izvirni znanstveni članek Opis: 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.
Ključne besede: dry sausages, additives, nitrites, phosphates, ascorbates
Objavljeno v DKUM: 04.07.2024; Ogledov: 109; Prenosov: 12
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3. 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, izvirni znanstveni članek Opis: 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.
Ključne besede: boar taint, morphometric indicators, immunocastration, entire males
Objavljeno v DKUM: 11.04.2024; Ogledov: 213; Prenosov: 6
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4. 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, izvirni znanstveni članek Opis: 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.
Ključne besede: response to immunocastration, pigs, anti-GnRH, morphometry, testicular mRNA expression
Objavljeno v DKUM: 16.08.2023; Ogledov: 490; Prenosov: 66
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5. 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, izvirni znanstveni članek Opis: 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.
Ključne besede: pigs, dietary supplements, tannins, parotid gland, mandibular gland, immunohistochemistry, histology, proline-rich proteins (PRP), swine
Objavljeno v DKUM: 07.07.2023; Ogledov: 506; Prenosov: 44
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6. Lipid metabolism, deposition and composition in different metabolic types of pigs : Ph. D. thesisKlavdija Poklukar Žnidaršič, 2022, doktorska disertacija Opis: 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.
Ključne besede: prašič, maščobno tkivo, lipidni metabolizem, lokalne pasme, moderni križanci, nekastrirani prašiči, imunokastrirani prašiči, kirurško kastrirani prašiči, selekcijski podpisi povezani s fenotipom, izražanje genov
Objavljeno v DKUM: 05.10.2022; Ogledov: 692; Prenosov: 6
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7. Zmanjšanje uporabe nitritov in polifosfatov pri predelavi sušenih klobasManja Ozmec, 2021, magistrsko delo Opis: 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.
Ključne besede: sušena klobasa, nitrit, polifosfati, askorbat
Objavljeno v DKUM: 17.09.2021; Ogledov: 804; Prenosov: 111
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8. Vpliv mutacije gena ryr1 na lastnosti pršuta pri krškopoljskih prašičihKatarina Horvat, 2020, magistrsko delo Opis: 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.
Ključne besede: mutacija gena RYR1, pršut, krškopoljski prašič
Objavljeno v DKUM: 20.10.2020; Ogledov: 1365; Prenosov: 79
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9. Vpliv spola in stopnje soljenja na kakovost pršutaGregor Sok, 2020, magistrsko delo Opis: Cilj naloge je bil ugotoviti, kako spol prašiča in dolžina soljenja stegen vplivata na fizikalno-kemijske in teksturne lastnosti pršuta. V ta namen smo predelali stegna dvanajstih prašičev, šestih kastratov in šestih svinjk. Vse leve noge smo uporabili za krajše (10 dni), vse desne noge pa za daljše soljenje (18 dni). Vsi ostali postopki med predelavo so bili enaki. Po zaključenem zorenju smo za nadaljnje analize odvzeli vzorce dveh mišic, semimembranosus (SM) in biceps femoris (BF). Stegna kastratov so se od stegen svinjk razlikovala le v zamaščenosti, kar se je med predelavo, v fazi soljenja, odrazilo v manjši izgubi mase. Po zaključenem zorenju se stegna kastratov in svinjk niso razlikovala v kemijsko-fizikalnih lastnostih, razen v indeksu proteolize, ki je bil manjši v mišičnini kastratov, kar kaže na manj izražene proteolitične procese pri slednjih. Skladno s tem je analiza teksturnih lastnosti pokazala, da je bil po zaključku zorenja pršut iz svinjk (ugotovljeno za mišico BF), bolj mehak, manj koheziven in manj gumijast. Vpliv spola je značilno vplival na barvo mastnine in mišičnine po zaključku zorenja, in sicer je bila barva mastnine in barva obeh mišic BF in SM pri svinjkah svetlejša kot pri kastratih. Trajanje soljenja je vplivalo na vsebnost soli v pršutu, ki je bila pri krajšem soljenju značilno zmanjšana. Prav tako je krajše soljenje vplivalo na teksturne lastnosti pršuta, saj je bil pršut, ki je bil izpostavljen krajšemu soljenju mehkejši (SM in BF), mišica SM je bila tudi manj kohezivna, gumijasta in žvečljiva.
Ključne besede: pršut, spol, soljenje, kakovost
Objavljeno v DKUM: 30.09.2020; Ogledov: 1078; Prenosov: 76
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10. Vpliv vključevanja krmnih dodatkov z antioksidativnim potencialom na barvo mesnih izdelkovHelena Zver, 2019, diplomsko delo/naloga Opis: V diplomski nalogi smo ugotavljali vpliv vključevanja krmnih dodatkov z antioksidativnim potencialom na barvo mesnih izdelkov (suhe vratovine in pancete). Vzorci mesnih izdelkov so izhajali iz poskusa, v katerem so prašiči v obdobju pitanja (60-130kg) dobivali krmo z različnimi krmnimi dodatki. Kontrolna skupina (n=9) je dobivala klasično krmo za pitanje, pri ostalih treh skupinah pa je bil v standardni obrok dodan hmelj (n=11), tanin (n=11) ali vitamin E (n=5). Barvo mesnih izdelkov smo merili s spektrokolorimetrom in sicer barvne parametre L* (svetlost), a* (odtenek rdeče barve) in b* (odtenek rumene barve). Pri vratovini smo barvo izmerili na svežem prerezu, pri panceti pa smo meritev ponovili še nekajkrat (6-krat v obdobju 1-6 ur ter 1, 2, 3, 4, 7, 14 in 21 dni po rezanju), s čimer smo želeli analizirati obstojnost barve. Krmni dodatki niso vplivali na barvo vratovine. Pri panceti smo ugotovili, da imajo krmni dodatki določen vpliv na barvo izdelka, vendar pa ne vplivajo na obstojnost barve (opažena je bila neznačilna interakcija med časom merjenja in krmnim dodatkom). Čas shranjevanja ni imel vpliva na barvni parameter L*, vrednosti parametra a* so ves čas merjenja padale, parametra b* pa naraščale. Med krmnimi dodatki sta nekoliko večji vpliv na barvo pokazala vitamin E in hmelj, vendar vpliv posameznega dodatka ni bil vselej enakoznačen, zaradi česar o kakršnem koli vidnejšem vplivu izbranih prehranskih dodatkov ne moremo sklepati.
Ključne besede: mesni izdelki, barva, krmni dodatki, antioksidanti
Objavljeno v DKUM: 01.03.2019; Ogledov: 2785; Prenosov: 79
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