ADVERSE EFFECTS OF WET DISTILLERS GRAINS WITH SOLUBLES (WDGS) IN THE DIET OF DAIRY COWS

Corn wet distillers grains with solubles (WDGS) included up to 25% in the diet of 16 Simmental dairy cows, 27 to 72 months old, during three weeks, negatively affected rumen function monitored by non-invasive parameters, such as fecal consistency, and also influenced milk quality by reducing milk fat content. Dry distillers' grains with solubles (DDGS) are currently the most attractive by-product of the bioethanol industry due to the possibility of application in the diet of various animal species, whereas WDGS is often more locally available and financially affordable; however, there is little data in the literature indicating potential negative consequences of its use. Therefore, this report aims to point out, based on a practical example, the possible problems of its application in the diet of dairy cows as the most metabolically sensitive category, as well as to demonstrate steps to prevent and/or mitigate eventual errors

Exploiting DNA repair defects in high-grade serous ovarian carcinoma

© 2020 Ksenija NesicHigh-Grade Serous Ovarian Carcinoma (HGSOC) is the most common subtype of ovarian cancer, and is the leading cause of ovarian cancer death. This subtype is molecularly characterised by frequent loss of Homologous Recombination (HR) DNA repair, making it susceptible to Poly-ADP ribose polymerase (PARP) inhibitor treatment. Despite the efficacy of PARP inhibitors (PARPi) in treating HGSOC, disease recurrence is common. A poor understanding of PARPi toxicity and resistance mechanisms has limited improvements in overall survival of patients. This project utilised HGSOC Patient-Derived Xenograft (PDX) and in vitro models to determine underlying mechanisms of PARPi sensitivity and resistance. Characterisation of the HGSOC PDX cohort led to the discovery of 2 models with HR gene secondary mutations, thereby explaining the poor PARPi responses of these tumours. Loss of the Classical Non-Homologous End-Joining (C-NHEJ) DNA repair pathway was also investigated but was not supported as a mechanism of resistance in PDX, or in a genome-wide PARPi-resistance CRISPR screen using a BRCA2-mutant cell line. The CRISPR screen revealed PARP1 mutations as the top hit, but no C-NHEJ mutation hits. CRISPR screens have also been optimised for a BRCA1-mutant cell line and a unique BRCA1 methylated cell line, to enable future validation in different HRD contexts. HR gene methylation analysis in the HGSOC PDX models revealed distinct BRCA1 promoter methylation profiles, subsequently found to represent “homozygous” and “heterozygous” methylation states. Our group demonstrated that all copies of BRCA1 must be methylated for gene silencing and PARPi response, and that methylation can be lost under treatment pressure in patients. I then investigated this mechanism in two HGSOC PDX models with RAD51C promoter methylation. RAD51C promoter methylation was found to have homogeneous or heterogeneous patterns, and both caused gene silencing and PARPi response in the PDX, that could be lost under treatment pressure. One third of patient samples tested appear to have a heterogeneous RAD51C methylation profile and, like the PDX, some responded to chemotherapy. To assess whether global methylation profiles influenced HR gene methylation stability, I carried out genome-wide methylation array analysis of PDX models and clinical samples. Analysis of cyclically PARPi re-treated RAD51C methylated tumours from one PDX model demonstrated increasing global losses in methylation with each treatment cycle. Through characterisation of the HGSOC PDX cohort and in vitro CRISPR screens, I have uncovered both well-established mechanisms of resistance (e.g. secondary mutations), and less studied mechanisms of sensitivity and resistance, such as loss of RAD51C methylation and PARP1 loss. These models provide a platform for further study of these PARPi resistance mechanisms, including potential therapeutics to prevent or overcome their development in the clinic

Examination of the efficacy of various feed additives on the pathomorphological changes in broilers treated with T-2 toxin

A 21-day-long experiment was performed on 160 one-day-old 'Ross' broiler chicks. This research was done with the aim of investigating pathomorphological changes in broilers exposed to a relatively small amount of T-2 toxin (2 ppm) and the possibility of prevention and/or alleviating adverse effects of T-2 toxin using various feed additives. Pathohistological examination showed negative consequences of T-2 toxin in all examined organs as degenerative changes developed in small intestine mucosa, enterocites and hepatocites necroses, as well as lymphocites depletion in bursa of Fabricius. Disparately from inorganic (Minazel-plus, Mz) and organic (Mycosorb, Ms) adsorbents, which did not provoke protective effects, in liver, small intestine and bursa of Fabricius of broilers who were given feed with T-2 toxin and mixed adsorbent (Mycofix-plus, Mf), mostly preserved structure of these organs could be noted.Eksperiment je izveden na 160 jednodnevnih brojlerskih pilića provenijencije 'Ross', u trajanju od 21 dan. Istraživanja su bila usmerena na omogućavanje detaljnijeg uvida u patomorfološke promene kod brojlera izloženih dejstvu relativno niskih doza T-2 toksina (2 ppm), kao i mogućnosti prevencije ili ublažavanja štetnih efekata korišćenjem različitih adsorbenata. Patohistološkom analizom isečaka tankog creva, jetre i Fabricijeve burze, uočeni su efekti T-2 toksina u svim ispitivanim organima, u vidu degenerativnih promena na sluznici tankog creva, nekroze enterocita i hepatocita, kao i deplecije limfocita u Fabricijevoj burzi. Za razliku od neorganskog (Minazel-plus, Mz) i organskog (Mycosorb, Ms) adsorbenta čijom primenom nije došlo do zaštitnog efekta, u tkivnim isečcima jetre, creva i Fabricijeve burze kod brojlera koji su putem hrane dobijali T-2 toksin i mešoviti adsorbent (Mycofix, Mf), zapaža se uglavnom očuvana struktura ispitivanih organa

Evaluation of the efficacy of different feed additives to adsorbe T-2 toxin in vitro

In the trial, in vitro HPTLC - High Performance Thin Layer Chomatography was used to determine the amount of 'free', i.e. unbound or non-decomposed T-2 toxin. Mean adsorption or degradation levels of T-2 toxin in examined feed aditives, in in vitro conditions, ranged from 26.06 to 34.84% and did not significantly differ among used adsorbents: inorganic (Minazel plus - Mz), organic (Mycosorb - Ms) and mixed (Micofyx - Mf). All these additives showed better adsorption ability in the acidic environment (pH3).In vitro ispitivanjem određivana je količina 'slobodnog' tj. nevezanog ili nerazgrađenog T-2 toksina tehnikom tankoslojne hromatografije (HPTLC - High Performance Thin Layer Chromatography). Prosečne vrednosti adsorpcije ili degradacije T-2 toksina ispitivanim adsorbentima u uslovima in vitro nisu se značajnije razlikovale u zavisnosti da li je bio umešan neorganski (Minazel plus, Mz), organski (Mycosorb, Ms) ili mešoviti adsorbent (Micofyx, Mf) i iznosile su od 26,06 do 34,84%. Svi ispitivani adsorbenti su pokazali veću sposobnost adsorpcije ovog toksina u kiseloj sredini (pH 3)

Mycotoxins in poultry production

All poultry is sensitive to mycotoxins. This partly depends on the type, age and production categories of poultry, their living conditions and nutritive status and partly on the type, quantity and duration of mycotoxin ingestion. The presence of mycotoxins results in significant health disorders and a decrease in production performances. This leads to considerable economic loss for the poultry industry - either direct losses, i.e. death of the poultry or the indirect ones, i.e. the decrease in body mass, number and quality of eggs, greater food conversion, and immunosuppression. Immunosuppression results in increased sensitivity to infective agents and a bad vaccinal response. Morevover, mycotoxin residues in poultry meat, eggs and products derived from them pose a threat to human health. In order to prevent and reduce the negative implications of mycotoxins in the poultry production, it is necessary to create both global and national strategies for combatting mycotoxins, advance diagnostic techniques and procedures, intensify the control of food quality, introduce new limits on the maximum amount of mycotoxins allowed in food and poultry feed used for certain species and categories of animals, and synchronise it with the European standards.Sva živina je osetljiva na mikotoksine u zavisnosti od vrste, starosne i proizvodne kategorije, uslova ambijenta i nutritivnog statusa, sa jedne strane, i vrste, količine i dužine unošenja mikotoksina, sa druge strane. Prisustvo mikotoksina rezultira značajnim poremećajem zdravlja i padom proizvodnih performansi, a samim tim i značajnim ekonomskim gubicima u živinarskoj industriji, kako direktnim, koji se očituju uginućem živine, tako i indirektnim, u vidu pada telesne mase, broja i kvaliteta jaja, veće konverzije hrane i imunosupresijom. Imunosupresija rezultira povećanom osetljivošću na infektivne agense i lošim vakcinalnim odgovorom. Opasnost po ljudsko zdravlje predstavljaju rezidue mikotoksina u živinskom mesu, jajima i proizvodima dobijenim od njih. Da bi se predupredile i smanjile negativne implikacije mikotoksina u živinarskoj proizvodnji potrebno je formirati kako globalne tako i nacionalne strategije za borbu protiv mikotoksina, unaprediti dijagnostičke tehnike i procedure, pooštriti kontrolu kvaliteta hrane, uvesti nove limite za maksimalne količine mikotoksina u hrani i hranivima za pojedine životinjske vrste i kategorije i uskladiti ih sa evropskim standardima

Efficacy of different adsorbents in alleviating zearalenone effects on performance of pigs

The investigation of the influence of zearalenone effects on performance of pigs and the possibility of the application of modified clinoptilolite (MC) and esterified glucomanane (EGM) in alleviating and/or prevention of harmful effects was performed by the experiment of pigs nutrition. The experiment lasted for 31 days, and the group of pigs was fed with uncontaminated feed while experimental groups were fed with feed containing 3.84 ppm of zearalenone. In pig feed of the second and third experimental group MC and EGM in the amount of 0,2 and 0,1% were added. The pigs of the control group accomplished daily growth of 0.569 kg with feed con- version of 1.793 kg. The presence of F-2 toxin in feed affected adversely production results. The addition of MC or EGM to contaminated feed improved production results, but not to the level of the control group. The obtained results point at the fact that adsorbents can only partially prevent harmful effects of F-2 toxin

Comparison of elisa and HPLC methods for the detection of mycotoxins by analysing proficiency test results

Different analytical techniques for the detection of mycotoxins have been developed in order to control the levels of mycotoxins in food and feed. Conventional analytical methods for mycotoxin determination are involving techniques such as thinlayer chromatography (TLC), high-performance liquid chromatography (HPLC) and gas chromatography (GC). Also, rapid methods for mycotoxin analysis have become increasingly important. Enzyme-linked immuno-sorbent assay (ELISA) is one of the most common rapid methods for determination of these natural contaminants. The aim of this study was to provide a comparison between two different methods of analysis (HPLC and ELISA) for the detection of different mycotoxins using data that originate from commercial proficiency tests. Based on the statistical evaluation of the results for both methods, in three proficiency tests for various mycotoxins (aflatoxins, ochratoxin and zearalenone), it could be concluded that both techniques can equally be used, although ELISA is considered to be the screening one

Effect of goat breed on the meat quality

The quality of goat meat has recently become an important aspect in the marketing of goats in Serbia. The aim of this study was to compare some goat meat quality parameters of various races and to determine the differences between them. Goat breeds were Balkan goat and Serbian white goat, both female in the age of four years. Analysis of quality parameters: chemical composition (moisture, protein, total fat, ash,), pH value, fatty acids, amino acids, microelements content, tenderness, cooking loss and colour measurements were done. Statistically significant difference was found between the samples of two groups of goat meat (P < 0.05) in relation to: live weight (kg), water (%), fat (%), protein (%) and ash (%), among 11 of 15 tested fatty acids, amino acid leucin, sensory examination of fresh meat for the palpatory evaluated firmness and in the content of copper and zinc. Statistically significant differences between the groups did not existed regarding the pH value, fatty acids eicosenoic, cis-heptadecenoic, t-elaidic, t-linolelaidic and amino acids alanine, arginine, aspartic acid, cysteine, glutamic acid, glycine, histidine, isoleucine, lysine, methionine, phenylalanine, proline, serine, threonine, tryptophan, tyrosine and valine. Also there was no statistically significant difference in instrumental testing of the meat color, sensory evaluation of surface color, visual evaluated structure, olfactory evaluated odor and iron and manganese. These results suggest that the race of animal has an impact on meat quality.Kozije meso ima otprilike istu hranljivu vrednost kao i ovčije (bliže rečeno više belančevina, a manje masti). Zbog niske zastupljenosti zasićenih masnih kiselina i holesterola, kozije meso u ishrani ljudi je zdravija alternativa u poređenju sa drugim vrstama crvenog mesa. Bez obzira na nutritivnu vrednost, ono je ipak manje cenjeno zbog specifičnog mirisa i ukusa koji su intenzivniji kod starijih životinja. U Srbiji se malo zna o kvalitetu kozijeg mesa u poređenju sa ostalim vrstama, a posebno je nedovoljno poznavanje kvaliteta mesa autohtonih rasa koza. Cilj ovog istraživanja bio je da se prikupe i uporede podaci hemijskog sastava, pH vrednosti, sastava masnih i amino kiselina, pojedinih mikroelemenata, boje i mekoće (instrumentalno), senzorne analize svežeg mesa i određivanje kala toplotne obrade srpske bele i balkanske koze iste starosti. Iz uzoraka m. longissimus dorsi, uzetih nakon klanja navedenih životinja, ispitivan je hemijski sastav i pH vrednost, primenom ISO metoda. Sastav masnih kiselina i određen je primenom gasne hromatografije (GC6890N, Agilent Tech., USA) i poređen je sa standardom masnih kiselina (standard mix of FAMEs 37, Supelco, USA). Aminokiseline u navedenim uzorcima određene su nakon hidrolize tkiva primenom AOAC metode 982.30. Određivanje mikroelemenata u mesu koza vršeno je u metodom AOAC method 999.10. Princip metode za određivanje kala toplotne obrade sastoji se u određivanju gubitka mase usled toplotne obrade uzorka. Određivanje mekoće je obavljeno aparatom Warner–Bratzler. Boja svežeg mesa je takođe određivana u m. longissimus dorsi upotrebom Minolta chromameter CR-400. Senzornu analizu su radili obučeni ocenjivači u skladu sa ISO metodom. Dobijeni rezultati su statistički obrađeni primenom programa MS-Excel 2003, ANOVA, i utvrđene razlike srednjih vrednosti poređene t-testom na nivou značajnosti 99 i 95%. Na osnovu dobijenih rezultata može se zaključiti da je postojala statistički značajna razlika u kvalitetu mesa između ispitivanih uzoraka