1. Implementation of food matrix effects into chemical food contaminant risk assessmentAna-Andreea Cioca, Tomaž Langerholc, Livija Tušar, 2022, izvirni znanstveni članek Opis: Food risk assessment plays an important role in protecting public health worldwide. Stakeholders involved in food risk assessment, such as national authorities, agencies, non-governmental organisations (NGOs), industry and consumers, need to properly understand the terminology of food risk assessment effectively. In this respect, the first part of the EU-FORA work programme (WP1) aimed to provide insights into the actual translation of two essential terms used in food risk assessment. ‘Hazard’ and ‘risk’ were first identified and compared between the English version of various food regulations and their equivalents in the national legislation of EU Member States. The comparison and critical evaluation revealed several inconsistencies. These inconsistencies could lead to misinterpretations, followed by errors in conducting risk assessments or communicating risks. We recommend that consistency is restored and maintained so that the message is properly communicated. The second part of the work programme (WP2) was focused on a specific area within chemical risk assessment (CRA). In this context, special attention was given to the impact of the food matrix on the bioaccessibility and bioavailability of heavy metals and metalloids. After collection and careful selection of data from scientific journals, a database with information on the bioaccessibility and bioavailability of cadmium (Cd), lead (Pb), mercury (Hg) and arsenic (As) in different food matrices was created for future statistical analyses related to dietary exposure.
Ključne besede: hazard, risk, food regulation, chemical contaminants, bioavailability, bioaccessibility, food matrix
Objavljeno v DKUM: 18.09.2023; Ogledov: 53; Prenosov: 5
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2. Spatial clusters of Varroa destructor control strategies in EuropeRobert Brodschneider, Johannes Schlagbauer, Iliyana Arakelyan, Aleš Gregorc, 2022, izvirni znanstveni članek Opis: Beekeepers have various options to control the parasitic mite Varroa destructor in honey bee colonies, but no empirical data are available on the methods they apply in practice. We surveyed 28,409 beekeepers maintaining 507,641 colonies in 30 European countries concerning Varroa control methods. The set of 19 different Varroa diagnosis and control measures was taken from the annual COLOSS questionnaire on honey bee colony losses. The most frequent activities were monitoring of Varroa infestations, drone brood removal, various oxalic acid applications and formic acid applications. Correspondence analysis and hierarchical clustering on principal components showed that six Varroa control options (not necessarily the most used ones) significantly contribute to defining three distinctive clusters of countries in terms of Varroa control in Europe. Cluster I (eight Western European countries) is characterized by use of amitraz strips. Cluster II comprises 15 countries from Scandinavia, the Baltics, and Central-Southern Europe. This cluster is characterized by long-term formic acid treatments. Cluster III is characterized by dominant usage of amitraz fumigation and formed by seven Eastern European countries. The median number of different treatments applied per beekeeper was lowest in cluster III. Based on estimation of colony numbers in included countries, we extrapolated the proportions of colonies treated with different methods in Europe. This suggests that circa 62% of colonies in Europe are treated with amitraz, followed by oxalic acid for the next largest percentage of colonies. We discuss possible factors determining the choice of Varroa control measures in the different clusters.
Ključne besede: Apis mellifera, COLOSS, beekeeping, acaricide, varroa control, survey results
Objavljeno v DKUM: 18.08.2023; Ogledov: 93; Prenosov: 11
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3. Virus prevalence in egg samples collected from naturally selected and traditionally managed honey bee colonies across EuropeDavid Claeys Bouuaert, Lina De Smet, Marleen Brunain, Bjørn Dahle, Tjeerd Blacquière, Anne Dalmon, Daniel S. Dezmirean, Dylan Elen, Janja Filipi, Alexandru Giurgiu, Aleš Gregorc, 2022, izvirni znanstveni članek Opis: Monitoring virus infections can be an important selection tool in honey bee breeding. A recent study pointed towards an association between the virus-free status of eggs and an increased virus resistance to deformed wing virus (DWV) at the colony level. In this study, eggs from both naturally surviving and traditionally managed colonies from across Europe were screened for the prevalence of different viruses. Screenings were performed using the phenotyping protocol of the ‘suppressed in ovo virus infection’ trait but with qPCR instead of end-point PCR and a primer set that covers all DWV genotypes. Of the 213 screened samples, 109 were infected with DWV, 54 were infected with black queen cell virus (BQCV), 3 were infected with the sacbrood virus, and 2 were infected with the acute bee paralyses virus. It was demonstrated that incidences of the vertical transmission of DWV were more frequent in naturally surviving than in traditionally managed colonies, although the virus loads in the eggs remained the same. When comparing virus infections with queen age, older queens showed significantly lower infection loads of DWV in both traditionally managed and naturally surviving colonies, as well as reduced DWV infection frequencies in traditionally managed colonies. We determined that the detection frequencies of DWV and BQCV in honey bee eggs were lower in samples obtained in the spring than in those collected in the summer, indicating that vertical transmission may be lower in spring. Together, these patterns in vertical transmission show that honey bee queens have the potential to reduce the degree of vertical transmission over time.
Ključne besede: honey bee, suppressed in ovo virus infection, vertical transmission, virus resistance
Objavljeno v DKUM: 18.08.2023; Ogledov: 59; Prenosov: 9
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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: 89; Prenosov: 9
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5. The potential of berula erecta in vitro for As bioaccumulation and phytoremediation of water environmentsJana Ambrožič-Dolinšek, Anja Podgrajšek, Nik Šabeder, Zdenka Mazej, Andreja Urbanek Krajnc, Biljana Todorović, Terezija Ciringer, 2023, izvirni znanstveni članek Opis: A potential plant species suitable for As bioaccumulation and phytoremediation of water environments could be the macrophyte Berula erecta. The objective of the present study was to investigate the effect of arsenate (As(V), C2H6AsNaO2∙3 H2O), predominant in freshwater systems, on the growth, development and low molecular weight thiols of Berula erecta under controlled tissue culture conditions in vitro. Uptake of total arsenate increased with increasing arsenate treatments, at a higher percentage in the roots than in the aboveground parts of the plants. Lower concentrations of As(V) (0.1, 1, 10 mg L−1) had a positive effect on growth, dry weight, length of roots and shoots and number of buds. High concentrations of arsenate (50 and 100 mg As(V) L−1) significantly inhibited all growth parameters and decreased the photochemical efficiency of PSII. Evaluation of thiols revealed the critical As level (146 µg g−1 DW; 50 mg As(V) L−1 treatment) above which the As concentration can be toxic.
Ključne besede: arsenic, arsenate, uptake, accumulation, thiols, apiaceae, lesser water-parsnip
Objavljeno v DKUM: 02.08.2023; Ogledov: 91; Prenosov: 23
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6. Kakovost izvedenih korektivnih ukrepov ob pojavu presežnih vrednosti mikroogranizmov v živilskem obratu - primer mesarije : diplomsko deloHana Koželjnik Kačičnik, 2023, diplomsko delo Opis: V okviru notranjega nadzora mora nosilec živilske dejavnosti zagotoviti zdravstveno ustreznost in varnost živil v vseh fazah proizvodnje in prometa z živili na podlagi veljavne zakonodaje in načel HACCP sistema (analiza tveganja in ugotavljanja kritičnih kontrolnih točk). Na primeru mesarije smo v sodelovanju z Inštitutom za sanitarno inženirstvo proučevali higiensko-tehnične zahteve za živilski obrat in preverjali učinkovitost korektivnih ukrepov ob pojavu preseženih vrednosti mikroorganizmov. V mesariji smo opravili mikrobiološke preskuse iz različnih površin in ugotovili presežne mejne vrednosti pri 70 % odvzetih vzorcev. Predlagali smo korektivne ukrepe (dezinfekcija in dodatno usposabljanje zaposlenih) in ugotavljali, ali so le-ti zadostni za izboljšanje higienskega stanja. Pri ponovnem pregledu mesarije, po opravljeni dezinfekciji, so bile vrednosti aerobnih mezofilnih bakterij v vseh odvzetih vzorcih pod dovoljenimi mejnimi vrednostmi (snažni vzorci). Dezinfekcija se je tako izkazala za učinkovit korektivni ukrep. Preverjanje znanja zaposlenih o higieni živil in HACCP sistemu je pokazalo pomanjkljivo poznavanje tematike s tega področja. Po izvedenem dodatnem izobraževanju zaposlenih se je stopnja znanja zaposlenih znatno povečala, prav tako je bila snažnost obrata v skladu s predpisanimi normativi. S tem smo potrdili, da je dodatno izobraževanje delavcev učinkovit ukrep za izboljšanje higienskega stanja v živilskih obratih, ki je ključno za zagotavljanje varnosti hrane in preprečevanje širjenja nalezljivih bolezni.
Ključne besede: varnost živil, HACCP sistem, mesarija, sanitarno-tehnični pregled, mikroorganizmi
Objavljeno v DKUM: 07.07.2023; Ogledov: 158; Prenosov: 35
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7. Poslovni načrt pridelave in predelave lešnikov : magistrsko deloSaša Guštin, 2023, magistrsko delo Opis: Navadna ali evropska leska (Corylus avellana L.) je po vsem svetu razširjena sadna vrsta, ki sodi med lupinasto sadje ali lupinarje. Zaradi svoje sestave so bili lešniki prepoznani kot zdravju koristno živilo. V magistrskem delu smo izdelali poslovni načrt pridelave in predelave lešnikov. Poslovni načrt je pisni dokument, ki opisuje predlagan podvig. Njegov namen je zmanjšati negotovosti v podjetniški dejavnosti. V okviru raziskave je bila narejena SWOT analiza, kjer smo definirali prednosti, slabosti, priložnosti in nevarnosti za pridelavo in predelavo lešnikov. S pomočjo metode kalkulacij skupnih stroškov smo ocenili pomembnejše ekonomske parametre pridelave in predelave (vrednost proizvodnje, lastno ceno, finančni rezultat, koeficient ekonomičnosti itd.). Naslednji cilj je bila ocena pomembnih parametrov finančne analize (neto sedanja vrednost, interna stopnja donosnosti in doba povratka investicije). Rezultati analize so pokazali, da sta pridelava in predelava lešnikov ekonomsko upravičeni. Investicija v pridelavo in predelavo se povrne ob upoštevanju nekonstantnega letnega denarnega toka v 9. letu. Pri razvoju poslovne ideje nam je bil v pomoč tudi poslovni model Canvas.
Ključne besede: lešniki, poslovni načrt, ekonomika, kalkulacije skupnih stroškov, ocena investicije
Objavljeno v DKUM: 05.07.2023; Ogledov: 184; Prenosov: 45
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8. Primerjava kakovosti nanosa FFS v nasadu jablan z ali brez uporabe elektrostatske podpore in kakovosti nanosa pri vožnji po vsaki ali vsaki drugi vrsti : magistrsko deloVeronika Turk, 2023, magistrsko delo Opis: Raziskava je bila izvedena v letu 2021 v ekološkem sadovnjaku podjetja Evrosad, d. o. o., v Savcih na sorti zlati delišes. Cilj naloge je bil preveriti učinkovitost zatiranja bolezni in škodljivcev jablane pri uporabi elektrostatskega nanosa z enako porabo vode in ob enakih delovnih parametrih kot pri nanosu brez elektrostatske podpore. Prav tako smo testirali učinkovitost škropljenja z uporabo elektrostatskega nanosa pri škropljenju vsake druge vrste jablan. Za oceno enakomernosti porazdelitve škropilne brozge smo uporabili tehniko vodoobčutljivih lističev. Kakovost depozita škropilne brozge smo ocenili z uporabo barvnega sledilca tartrazin, katerega koncentracijo na listih smo določili z uporabo fotospektrometra. Ocena stopnje napada zaradi bolezni in škodljivcev je bila večkrat letno narejena po standardnih metodah EPPO, pri čemer smo uporabili metodo vizualnega bonitiranja deleža napadene površine opazovanega organa. V poskusu pri danih parametrih nismo potrdili postavljenih hipotez, da uporaba elektrostatike značilno izboljša uspešnost zatiranja škodljivih organizmov in da lahko škropljenje preko dveh vrst ob uporabi elektrostatike daje enakovreden rezultat kot škropljenje vsake vrste nasada jablan.
Ključne besede: fitofarmacevtska sredstva, elektrostatska podpora, pršenje
Objavljeno v DKUM: 05.07.2023; Ogledov: 106; Prenosov: 7
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9. Analiza uporabe dodatka superabsorcijskega polimera v rastni substrat na morfoagronomske lastnosti sadik solate lettuca sativa var. comice (bvp4883) : magistrsko deloAndrej Smodič, 2023, magistrsko delo Opis: V magistrskem delu smo analizirali vpliv dodajanja superabsorberja (SA) v obliki kalijevega poliakrilata na življenjsko dobo sadik solate Lattuca sativa L. Var. Comice (BVP4883) in po metodi stroškov in koristi pregledali ekonomsko smiselnost dodajanja omenjenega SA.
Rezultati poskusa potrjujejo, da lahko z dodatkom SA povečamo količino zadrževane vode v vsebnikih sadik, kar kažejo podatki iz prvega tehtanja. Vezana voda zaznavno v zelo podobni intenziteti zapušča vsebnike z in vsebnike brez dodatka SA.
V ugodnih pogojih je obdobje, ko so rastline še primerne za prodajo (ocena več kot 3), za 5 dni daljše v vsebnikih z dodanim SA kot pri kontroli, kar pomeni, da se prodajno obdobje zaradi tega dejansko podvoji.
V manj ugodnih pogojih ocena rastlin več kot 3 ostane pri vsebnikih z dodanim SA le en dan dlje kot pri kontroli. Sadike pod tovrstnimi neugodnimi pogoji ne vzdržijo niti običajnega prodajnega obdobja, ki traja 5 dni.
Dodajanje SA v vsebnike sadik solatnic na pregledovanem primeru pomeni povečanje PLC vsebnika za 2,1%.
Glede na dosežene rezultate ocenjujemo, da se zaradi podaljšanja časa v prodaji lahko trgovinski kalo zniža za vsaj 40%.
Znižani kalo, ki neposredno vpliva na prihodke ter količino vračila in tudi vrednost sanacije vračila, daje izjemno pozitiven učinek glede gospodarnosti tovrstne pridelave.
Točka preloma pri % kala na osnovi podanih predpostavk in brez upoštevanja stroškov sanacije kala znaša pri poskusu s SA 4,9 % in pri kontroli brez SA 6,8 %.
Ključne besede: superabsorpcijski polimeri, kalijev poliakrilat, pridelava sadik, ekonomičnost
Objavljeno v DKUM: 05.07.2023; Ogledov: 132; Prenosov: 7
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10. Možnosti kemičnega zatiranja stenice marmorirane smrdljivke (Halyomorpha halys Stål) v nasadih jablan z ekološko in integrirano pridelavo : magistrsko deloAnja Preložnik, 2023, magistrsko delo Opis: V letu 2021 smo izvedli poljska poskusa, v katerih smo preučevali učinkovitost ekološkega in integriranega škropilnega programa na zatiranje stenice marmorirane smrdljivke (Halyomorpha halys Stål) v dveh ločenih nasadih jablan na Primorskem. Ocenjevali smo velikost populacije odrasle stenice, njenih ličink in delež plodov s poškodbami v 9- do 12-dnevnih presledkih. Škropilni program v ekološkem nasadu, temelječ na rastlinskih izvlečkih, naravnih piretrinih, spinosadu, kaolinu, naravnih milih in azadirahtinu, je bil v povprečju med 45- in 66-odstotno učinkovit za zatiranje stenic in je za 65 do 78 odstotkov zmanjšal delež plodov s poškodbami ob obiranju. Pri dveh integriranih škropilnih programih, temelječih na uporabi snovi acetamiprid, deltametrin, fosmet, spinosad in rastlinskih izvlečkov, smo dosegli od 69- do 93-odstotno učinkovitost pri zatiranju odraslih stenic. Uporaba pripravkov v integriranem programu je za 70 do 80 odstotkov zmanjšala delež plodov, poškodovanih od stenic, ob obiranju. Iz podatkov, ki smo jih dobili v poskusu, lahko sklepamo, da so lahko škropilni programi, ki temeljijo na podlagi testiranih razpoložljivih aktivnih snovi, do 80-odstotno učinkoviti. To kaže, da zgolj z uporabo testiranih pripravkov ni možno zagotoviti dovolj temeljitega zatiranja stenice. Hkrati je z uporabo insekticidov treba izvajati še druge biotične in biotehniške metode zatiranja.
Ključne besede: marmorirana smrdljivka, kemično zatiranje, jablana
Objavljeno v DKUM: 04.07.2023; Ogledov: 106; Prenosov: 9
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