Prof. Dr. Halis Oguz | Selcuk University (Selçuk Üniversitesi) (original) (raw)

Papers by Prof. Dr. Halis Oguz

Aflatoxin B1 (AFB1), produced by various species of toxigenic fungi, is among the most potent gen... more Aflatoxin B1 (AFB1), produced by various species of toxigenic fungi, is among the most potent genotoxic and carcinogenic mycotoxins which act as a major source of distress for the growing poultry sector while distillery yeast sludge or distillery sludge (DS) is a byproduct of molasses-based industries and often treated as a waste despite of containing abundant nutrients particularly protein contents, basic amino acids and vitamins along with other macro and micronutrients. This study was designed to investigate the oxidative stress and immunological alterations induced by AFB1 and their amelioration by dietary supplementation of DS. 3. For this purpose, 360 newly hatched broiler chicks were randomly divided into twelve groups (30 birds each) and fed different combinations of AFB1 (100, 200 and 600 µg/kg) and DS (5 and 10 g/kg) for 42 days. The parameters under consideration were total antioxidant capacity, antibody response to intravenous injection of sheep red blood cells, in-situ ...

British Poultry Science, 2022

1. Aflatoxins’ (AFs) are metabolites which especially have toxic effects on proteins, and are det... more 1. Aflatoxins’ (AFs) are metabolites which especially have toxic effects on proteins, and are detoxified by the aflatoxin-B1 aldehyde reductase (AFAR) pathway. In this pathway, the aldo-keto reductase family 7, member A2 (AKR7A2) enzyme is controlled by nucleic-related erythroid factor 2 (Nrf2) plays an active role. However, data on the efficacy of this critical pathway in broilers is limited. 2. The aim of the following study was the changes in the expression levels of AKR7A2, Nrf2, and caspase-3, and the effects of Nigella sativa seeds (NS), thymoquinone (TMQ), and bentonite (BNT) on expression were investigated in broilers exposed to AFs. 3. One-hundred broilers were divided into ten groups (control (CNT); AF; NS; TMQ; BNT; AF+TMQ; AF+NS; AF+BNT; AF+BNT+NS; AF+BNT+TMQ) and fed for 28 d. AF. TMQ, NS and BNT were added to diets at levels of 2 mg/kg, 300 mg/kg, 50 g/kg and 10 g/kg respectively. 4. The addition of AF to the diet decreased AKR7A2 and Nrf2 levels dramatically, but increased caspase-3 (P<0.01). TMQ, NS and BNT additions to the diet eliminated all negative effects caused by AF (P<0.01); and AKR7A2 and Nrf2 were further raised in TMQ and NS groups when compared to the control group. TMQ and NS showed a positive effect on detoxification parameters when given together with BNT. 5. Supplementation with NS and TMQ enhanced AF detoxification via the AFAR pathway, by increasing AKR7A2 and Nrf2 levels, in addition to reducing hepatocyte apoptosis.

Journal of Veterinary Pharmacology and Therapeutics, 2021

The aim of this study was to determine the pharmacokinetics and bioavailability of tolfenamic aci... more The aim of this study was to determine the pharmacokinetics and bioavailability of tolfenamic acid in goats after intravenous (IV), intramuscular (IM), subcutaneous (SC), and oral (PO) administrations at 2 mg/kg dose. In this study, eight clinically healthy goats were used. The study comprised four periods, according to a crossover design with at least a 15-day washout period between treatments. Plasma concentrations of tolfenamic acid were determined by HPLC-UV, and the pharmacokinetic parameters were estimated using a non-compartmental method. Following IV administration, terminal elimination half-life, volume of distribution at steady state, and total clearance were 1.60 h, 0.37 L/kg, and 0.27 L/h/kg, respectively. The mean peak plasma concentration following IM, SC, and PO administrations was 1.77, 1.22, and 0.30 μg/ml, respectively. The mean bioavailability following IM, SC, and PO administrations was 64.46, 55.43, and 19.46%, respectively. The PO route, which exhibits both the low plasma concentration and bioavailability, is not recommended in goats. The IV, IM, and SC routes, which show comparable pharmacokinetic profiles, may be proposed for use in goats. However, the multi-dose and pharmacodynamic studies are necessary to establish more accurately its safety and efficacy in the goat.

Eurasian Journal of Veterinary Sciences, 2011

Bu meta-analitik derlemede kanatlı yemlerindeki aflatoksinlerin etkisizleştirilmesi ile ilgili ge... more Bu meta-analitik derlemede kanatlı yemlerindeki aflatoksinlerin etkisizleştirilmesi ile ilgili genel bilgiler verildikten sonra bu amaçla yem katkısı şeklinde kullanılan adsorbanlar ve biyolojik ürünlerle yapılan in vivo deneysel çalışmalar özetler halinde sunuldu. Bu amaçla 33 farklı ülkede gerçekleştirilen toplam 135 araştıma tarandı ve sonuçları ana hatlarıyla verildi. Bu derleme ile ilgili konuda yapılan tüm çalışmalar ve sonuçlarının konu ile ilgilenen sektör ve bilim temsilcilerine ülkeler bazında toplu halde sunulması ve onların bütüncül bir değerlendirme yapmalarına imkan sağlanması amaçlandı.

British Poultry Science, 2021

1. Aflatoxins' (AFs) are metabolites which especially have toxic effects on proteins, and are... more 1. Aflatoxins' (AFs) are metabolites which especially have toxic effects on proteins, and are detoxified by the aflatoxin-B1 aldehyde reductase (AFAR) pathway. In this pathway, the aldo-keto reductase family 7, member A2 (AKR7A2) enzyme is controlled by nucleic-related erythroid factor 2 (Nrf2) plays an active role. However, data on the efficacy of this critical pathway in broilers is limited.2. The aim of the following study was the changes in the expression levels of AKR7A2, Nrf2, and caspase-3, and the effects of Nigella sativa seeds (NS), thymoquinone (TMQ), and bentonite (BNT) on expression were investigated in broilers exposed to AFs.3. One-hundred broilers were divided into ten groups (control (CNT); AF; NS; TMQ; BNT; AF+TMQ; AF+NS; AF+BNT; AF+BNT+NS; AF+BNT+TMQ) and fed for 28 d. AF. TMQ, NS and BNT were added to diets at levels of 2 mg/kg, 300 mg/kg, 50 g/kg and 10 g/kg respectively.4. The addition of AF to the diet decreased AKR7A2 and Nrf2 levels dramatically, but increased caspase-3 (P<0.01). TMQ, NS and BNT additions to the diet eliminated all negative effects caused by AF (P<0.01); and AKR7A2 and Nrf2 were further raised in TMQ and NS groups when compared to the control group. TMQ and NS showed a positive effect on detoxification parameters when given together with BNT.5. Supplementation with NS and TMQ enhanced AF detoxification via the AFAR pathway, by increasing AKR7A2 and Nrf2 levels, in addition to reducing hepatocyte apoptosis.

Research in Veterinary Science, 2001

Indian Journal of Animal Research, 2015

Archivum veterinarium Polonicum / Polish Academy of Sciences, Committee of Veterinary Sciences

In this review the toxicological features of pyretroids, their uses and importance in veterinary ... more In this review the toxicological features of pyretroids, their uses and importance in veterinary medicine, public health and environmental sanitation were summarised.

Research in Veterinary Science, 2000

Introduction: Aflatoxin B1 is naturally occurring mycotoxin that is produced by many species of A... more Introduction: Aflatoxin B1 is naturally occurring mycotoxin that is produced by many species of Aspergillus, a fungus, most notably Aspergillus flavus and Aspergillus parasiticus, bifurano-coumarin derivative. Aflatoxins B1 is toxic and is one of the most potent hepato-carcinogens mycotoxins known. It appears to occur much frequently in silage, although analytical methods for its determination have not been always have been dedected. Experimental: This presentation deals with the planar chromatographyh method for determination of aflatoxin B1 in silage. Dried and ground silage (20 g) was mixed with 10 ml and 100 ml chloroform and shaken for 10 min. Decant through filter paper into 50 ml glass-stopper. Added ca. 10 g anhydrous Na2SO4 to 50 ml filtrate. Prepared Florosil column for cleanup as fallows: Inserted glass wool in bottom of chromatographic column. Added 5 g anhydrous granulated Na2SO4, 0.7 g Florosil, and 0.5 g anhydrous granulated Na2SO4. Washed column with 30 ml chloroform...

During 2009 ‐ 2012 period, mixed feeds (n=56) and feed ingredients (n=59), from differenteight pr... more During 2009 ‐ 2012 period, mixed feeds (n=56) and feed ingredients (n=59), from differenteight provinces (Afyonkarahisar, Aksaray, Antalya, Burdur, Isparta, Karaman, Konya and Niğde), submitted to Toxicology Laboratory, Konya Veterinary Control Institute with suspected aflatoxins(B1 (AFB1), B2 (AFB2), G1 (AFG1), G2 (AFG2)) were analyzed in this study. Samples were analyzed for aflatoxin using thin layer chromatographic and semi‐quantitativemethod for detection and quantification. A floriosil column was used during preparation of samples. AFB1 was found in 16 samples of mixed feed (28.6 %) and 9 feed ingredient (15.3 %) whereas AFB2 in 2 mixed feed (3.6 %) and 3 feed ingredients (5.1 %). AFG1 and AFG2 were detected in only one sample of feed ingredients (1.7 %). It was found that AFB1 levels in mixed feed samples ranged from 1 to 20 g/kg and were 0.5 to 60 g/kg in feed ingredient samples. However AFB2 levels in mixed feed samples ranged from 0.2 to 2 g/kg and were 0.5 to 15 g/kg in f...

Research in Veterinary Science, 2000

Research in Veterinary Science, 2002

Research in Veterinary Science, 2005

Revue Méd. …, 2011

... 4. - BATRA P., PRUTHI AK, SADANA JR: Effect of aflatoxin B1 on the efficacy of turkey herpesv... more ... 4. - BATRA P., PRUTHI AK, SADANA JR: Effect of aflatoxin B1 on the efficacy of turkey herpesvirus vaccine against Marek's disease. ... 16. - KONUK T.: Pratik Fizyoloji, Konuk T. (ed.), Ankara Universitesi Ve-teriner Fakultesi Yayınları, AU Basımevi, Ankara, 1981, 378, pp.: 90-103. ...

British Poultry Science, 2000

1. The amelioration of aflatoxicosis in broiler chickens was examined by feeding 2 concentrations... more 1. The amelioration of aflatoxicosis in broiler chickens was examined by feeding 2 concentrations of natural zeolite (clinoptilolite). Clinoptilolite (CLI), incorporated into the diet at 15 and 25 g/kg, was evaluated for its ability to reduce the deleterious effects of 2.5 mg total aflatoxin (AF; 76.40% AFB1, 16.12% AFB2, 6.01% AFG1 and 1.47% AFG in diet on growing broiler chicks from 1 to 21 d of age. A total of 360 broiler chicks were divided into 6 treatment groups (6 replicates of 10 broilers each): control, AF, CLI (15 g/kg), AF plus CLI (15 g/kg), CLI (25 g/kg), and AF plus CLI (25 g/kg). 2. Compared to controls, the treatment had significantly decreased body weight gain from week 1 onwards. The adverse effect of AF on food consumption (8.0%) and food conversion ratio (8.3%) was also shown over the entire 21-d feeding period. 3. The addition of CLI (15 g/kg) to an AF-containing diet significantly reduced the deleterious effects of AF on food consumption and body weight gain. Food conversion ratio was also slightly improved by adding CLI (15 g/kg) to AF-containing diets. Food consumption, body weight gain and food conversion ratio values were rendered numerically intermediate between AF and control groups by the addition of CLI (25 g/kg) to the AF-containing diet. 4. The addition of CLI (both 15 and 25 g/kg) to the AF-free diet did not produce any significant changes compared with the controls, except for decreased total food consumption in the CLI (25 g/kg)-alone group. 5. These results suggest that CLI (15 g/kg) addition effectively diminished the detrimental effects of AF on the values investigated. Also, the lower dietary concentration of CLI (15 g/kg) was more effective than the greater concentration against the adverse effects of AF on the variables investigated in this study.

British Poultry Science, 2000

1. The embryotoxicity of mixed aflatoxins (AF) and aflatoxin B1 (AFB1) were evaluated by a modifi... more 1. The embryotoxicity of mixed aflatoxins (AF) and aflatoxin B1 (AFB1) were evaluated by a modified chick embryotoxicity screening test (CHEST). Adverse effects on the early embryonic development of thymus and bursa of Fabricius were also investigated by light microscopy. AF consisted of 83.06% AFB1, 12.98% AFB2, 2.84% AFG1 and 1.12% AFG2. 2. A total of 448 fertilised laying hens' eggs were used. AF and AFB1 were injected into the eggs at doses of 10, 100 and 1000 ng/egg. Embryonic developmental stages were evaluated according to the Hamburger-Hamilton scale (HH-scale). 3. The results showed that AFB1 given at 10 ng/egg had a significantly (P<0.05) greater embryotoxic effect than AF given at a similar dose. The higher doses of both AF and AFB1 caused higher embryonic mortality and also an increase in early deaths. 4. In the groups receiving 100 ng/egg AF and AFB1 an abnormal development was seen, with a protruded central region, corresponding to the area pellucida of the blastoderm. No other developmental abnormality attributable to AF or AFB1 was found.

British Poultry Science, 2000

1. Protective action of an enzyme-linked polyvinylpolypyrrolidone (PVPP, Mycofix Plus) against th... more 1. Protective action of an enzyme-linked polyvinylpolypyrrolidone (PVPP, Mycofix Plus) against the immunosuppressive effect of afatoxins (AF) was evaluated by determination of peripheral blood T-lymphocyte proportions and splenic plasma cell counts. Histological changes in lymphoid organs were also investigated by light microscopy. One-d-old broiler chicks (Hybro) received 2.5 mg/kg diet AF (83.06% AFB1, 12.98% AFB2, 2.84% AFG1, 1.12% AFG2) with or without PVPP (3g/kg diet) until 21 d of age. When compared with controls, AF treatment significantly decreased peripheral T-lymphocyte counts. AF caused a slight decrease in splenic plasma cell counts. The addition of PVPP to an AF-containing diet significantly increased T-lymphocyte counts. Splenic plasma cell counts were numerically intermediate between control and AF groups. 3. The dietary addition of PVPP to AF-free diet did not significantly alter either T-lymphocyte or splenic plasma cell counts.

British Poultry Science, 2022

Journal of Veterinary Pharmacology and Therapeutics, 2021

Eurasian Journal of Veterinary Sciences, 2011

British Poultry Science, 2021

Research in Veterinary Science, 2001

Indian Journal of Animal Research, 2015

Archivum veterinarium Polonicum / Polish Academy of Sciences, Committee of Veterinary Sciences

Research in Veterinary Science, 2000

Research in Veterinary Science, 2002

Research in Veterinary Science, 2005

Revue Méd. …, 2011

British Poultry Science, 2000

British Poultry Science , 2022

2. The aim of the following study was the changes in the expression levels of AKR7A2, Nrf2, and caspase-3, and the effects of Nigella sativa seeds (NS), thymoquinone (TMQ), and bentonite (BNT) on expression were investigated in broilers exposed to AFs.

3. One-hundred broilers were divided into ten groups (control (CNT); AF; NS; TMQ; BNT; AF+TMQ; AF+NS; AF+BNT; AF+BNT+NS; AF+BNT+TMQ) and fed for 28 d. AF. TMQ, NS and BNT were added to diets at levels of 2 mg/kg, 300 mg/kg, 50 g/kg and 10 g/kg respectively.

4. The addition of AF to the diet decreased AKR7A2 and Nrf2 levels dramatically, but increased caspase-3 (P<0.01). TMQ, NS and BNT additions to the diet eliminated all negative effects caused by AF (P<0.01); and AKR7A2 and Nrf2 were further raised in TMQ and NS groups when compared to the control group. TMQ and NS showed a positive effect on detoxification parameters when given together with BNT.

5. Supplementation with NS and TMQ enhanced AF detoxification via the AFAR pathway, by increasing AKR7A2 and Nrf2 levels, in addition to reducing hepatocyte apoptosis.