Hakan Öztürk

Hakan Öztürk

*This is an algorithmically generated author record based on publicly available information.

Current Organizations / Institutes

The organizations/institutes from the scholar's latest article


Hakan Öztürk has a total of 29 co-authors. Here are the top co-authors by number of shared publications:


Latest Publications

  • Effects of capsaicin on rumen fermentation under normal and acidosis pH conditions: A comparative Rusitec study with monensin

    by Melis Unler, Hakan Öztürk

    Capsaicin (CAP), the pungent component of chili peppers, possesses antimicrobial activity against a broad range of bacteria. This study evaluated the in vitro effects of CAP on ruminal fermentation under normal and acidic (SARA) pH conditions using the Rusitec system, in comparison with monensin (MON). By isolating pure capsaicin and applying a controlled dual-pH design, this study addresses uncertainty regarding CAP’s specific regulatory role in the rumen, thereby distinguishing its effects from those of complex phytochemical blends. The 18-day trial included adaptation, normal fermentation, and acidosis phases. CAP was tested at 1, 5, and 25 mg/L alongside MON (5 mg/L) under a high-concentrate diet (20:80). CAP significantly reduced ruminal pH at all doses, while SARA induction caused a clear phase-dependent pH decline in all fermenters. Total volatile fatty acids (VFA) production was unaffected by treatments but decreased during acidosis. MON increased propionate under both pH conditions, whereas CAP showed no effect. Only the CAP5 and CAP25 groups had higher methane production than the MON group. Protozoal counts were lowest in the MON group. NH₃-N and dry matter digestibility declined solely due to acidosis. Overall, at the tested doses, CAP exerted minimal influence on ruminal fermentation compared with MON.

  • Impact of lysozyme on ruminal fermentation and microbial population in Rusitec fermenters

    by Saad Ahmed Adam Musa, Ahu Demirtaş, Hakan Öztürk

    The aim of the present study was to investigate the in vitro effects of two lysozyme doses (10 and 50 FIP U/mL) on rumen fermentation and microbial populations using the artificial rumen system Rusitec with an 80:20 concentrate-to-forage diet. The ruminal pH, the total number of protozoa, total and individual volatile fatty acid (VFA) production, and methane (CH4) release were not significantly affected by the tested quantities of lysozyme. However, the ammonia nitrogen (NH3-N) concentration was significantly increased by supplementation with Lysozyme-50 (P < 0.05). The dry matter digestibility (DMD) was significantly higher in Lysozyme-50 than in Lysozyme-10 (P < 0.05). The total bacterial count decreased linearly in response to the addition of Lysozyme-50 (P < 0.05). Furthermore, in the presence of Lysozyme-50, the abundance of Butyrivibrio fibrisolvens decreased in both linear and quadratic manners (P < 0.05), and the abundance of Fibrobacter succinogenes decreased in a linear manner (P < 0.05). A linear decline tendency in the cell numbers of Ruminococcus albus (P = 0.092) and Megasphaera elsdenii (P = 0.085) was observed with Lysozyme-50 treatment. These findings suggest that while core fermentation parameters such as VFA production and digestibility remained stable, the elevated ammonia nitrogen concentration may reflect reduced nitrogen utilization efficiency, particularly at high doses. Additionally, since lysozyme has limited selectivity for certain rumen bacteria within the Rusitec system, lysozyme may influence rumen microbes differently from conventional antibiotics, warranting further in vitro and in vivo studies across diverse diets and dose ranges.


  • Open Access

    Effects of the Ketogenic Diet on Microbiota Composition and Short-Chain Fatty Acids in Women with Overweight/Obesity

    by Müge Güzey Akansel, Murat Baş, Cansu Gençalp, Meryem Kahrıman, Eray Şahin, Hakan Öztürk, Gürsel Gür, Ceren Gür

    Background/Objectives: The ketogenic diet (KD) is a dietary model that can impact metabolic health and microbiota and has been widely discussed in recent years. This study aimed to evaluate the effects of a 6-week KD on biochemical parameters, gut microbiota, and fecal short-chain fatty acids (SCFAs) in women with overweight/obesity. Methods: Overall, 15 women aged 26–46 years were included in this study. Blood samples, fecal samples, and anthropometric measurements were evaluated at the beginning and end of this study. Results: After KD, the mean body mass index decreased from 29.81 ± 4.74 to 27.12 ± 4.23 kg/m2, and all decreases in anthropometric measurements were significant (p < 0.05). Fasting glucose, insulin, homeostasis model assessment of insulin resistance, hemoglobin A1C, urea, and creatinine levels decreased, whereas uric acid levels increased (p < 0.05). Furthermore, increased serum zonulin levels were noted (p = 0.001), whereas fecal butyrate, propionate, acetate, and total SCFA levels decreased (p < 0.05). When the changes in microbiota composition were examined, a decrease in beta diversity (p = 0.001) was observed. After the intervention, a statistically significant increase was noted in the Firmicutes/Bacteroidetes ratio (p = 0.001). Although Oscilibacter, Blautia, and Akkermensia relative abundances increased, Prevotella relative abundance and Bifidobacter abundance, which were the dominant genera before the KD, decreased. Moreover, the abundance of some pathogenic genera, including Escherichia, Klebsilella, and Listeria, increased. Conclusions: In healthy individuals, KD may cause significant changes in microbial composition, leading to dysbiosis and long-term adverse outcomes with changes in serum zonulin and fecal SCFA levels.


  • Open Access

    Preliminary study of the effects of Apilactobacillus kunkeei EIR/BG-1 and Enterococcus hirae EIR/CM-2 supplementation on in vitro rumen fermentation and microbial population

    by A. Demirtas, S. Sevin, S. A. A. Musa, M. Sudagidan, N. N. Toprak, Y. Salgirli Demirbas, F. Kiran, H. Ozturk

    The aim of the study was to assess the impact of potential probiotic strains of lactic acid bacteria (LAB), Apilactobacillus kunkeei EIR/BG-1 isolated from the gut of honeybees, and Enterococcus hirae EIR/CM-2 isolated from cow’s milk, on rumen fermentation parameters and microbial...


  • Rumen physiology: microorganisms, fermentation and manipulation

    by Hakan Öztürk, Gursel Gur

    Ruminants are the unique animals with their energy conversion ability form forages to edible products. Therefore, rumen fermentation has been for long years excessively on the scope of researchers. Improvements of rumen fermentation is vital issue to meet the quality food demand grooving population of man. This review focuses on physiology and recent improvements in rumen fermentation. Ruminantlar, bitki yapısal unsurlarından oluşan kaba yemin tüketilebilir ürünlere dönüştürülmesinde eşsiz hayvanlardır. Bu nedenle, rumen fermentasyonu konusu bilim insanları tarafından uzun yıllardır yoğun bir şekilde araştırılmaktadır. Rumen fermentasyon performansında elde edilen ilerlemeler nüfusu hızla artan insanlığın kaliteli gıda ihtiyacının karşılanmasında hayati öneme sahiptir. Bu derlemede rumen fermentasyonu fizyolojisi ve son zamanlarda ki ilerlemeler ele alınmıştır.


  • Open Access

    METHANE MITIGATION STRATEGIES IN RUMINANTS

    by Gürsel Gur, Hakan Öztürk

    Küresel ısınma gezegenimizin bugünü ve geleceği için çok ciddi bir tehdittir. Çok sayıda faktörün sorumlu olduğu küresel ısınma sorununa ruminantlar da önemli katkı sağlamaktadır. Rumen fermantasyonu sonucu oluşan önemli miktarda metan gazı (CH4) yakın gelecekte insan nüfus artışına paralel olarak ruminantların da sayısının artmasıyla çok daha etkili bir sorun olacaktır. Bu nedenle son yirmi yıldır rumen fermantasyonu sırasında metan gazı oluşumunu önlemek maksadıyla çok sayıda araştırma yapılmıştır. Özellikle ikincil bitki metabolitleri, daha önceleri yem katkı maddesi olarak kullanımları yaygın olan iyonofor grubu antibiyotiklerin etkilerine benzer etkileriyle önemli bir potansiyel oluşturmaktadır. Bu derlemede rumen fermantasyonu sırasında oluşan metan gazının azaltılmasına yönelik çalışmalar incelenerek geleceğe yönelik öncelikli araştırılması gereken konular belirlenmeye çalışılmıştır.


  • The role of bio-detection dogs in the prevention and diagnosis of infectious diseases: A systematic review

    by Yasemin Salgirli Demi̇rbaş, Bülent Baş, Hakan Öztürk, Gorkem Ki̇smali̇, Merve Alpay, Hale Seçi̇lmi̇ş Canbay, Fatih Emen, Barış SAREYYÜPOĞLU, Aykut Özkul

    Infectious diseases are lately considered as one of the most important global risks which negatively impact not only the health but also the economy of countries. Globalization influences spread of infectious diseases as a result of new patterns of human travel and increased human interaction. Thus, in the new world, it is very important to prevent and diagnose the new infectious diseases by using accurate and quick diagnostic methods. Bio-detection dogs have a great potential to accurately diagnose infectious disease as they have a great ability to discriminate the volatile organic compounds (VOCs) which are specific to disease. This review discusses the potential use of bio-detection dogs in prevention and diagnosing of infectious disease. Moreover, factors affecting the scent of disease, i.e. VOCs, are tried to be highlighted. Keywords: Bio-detection dogs, diagnosis, infectious disease, volatile organic compound (VOC)


  • Open Access

    Consciousness for animal welfare: A trial of multidisciplinary education.

    by Etkin Şafak, Begüm Saral, Yasemin Salgirli Demi̇rbaş, Hakan Öztürk, Mehmet Bahri Emre

    Tr en Kedi ve köpekler yüzyıllardır çeşitli koşullarda ve çeşitli sebeplerden dolayı insanlarla birlikte yaşamaktadırlar.Farklı barınma koşulları, sahiplerinin beklenti ve tutumları gibi çeşitli faktörler evcil hayvanların refahını etkileyebilir. Hayvanların refah seviyelerini belirleyen çevrenin ihtiyaçlarını karşılamasını sağlamak veteriner hekimlerin, özellikle de hayvan davranışı uzmanlarının sorumluluğundadır. Farklı ev hayvanlarının ihtiyaçlarını karşılayabilmek için, kullanılacak ürünler bu ihtiyaçlara paralel olarak tasarlanmalıdır. Evcil hayvanların ihtiyaçlarını tam olarak karşılayan ürünlerin sadece tasarım ve hayvan davranışlarını içeren multidisipliner bir eğitim modeli ile mümkün olduğu düşünülmektedir. Bu çalışmada, Orta Doğu Teknik Üniversitesi Endüstriyel Ürün Tasarımı Bölümü 3. sınıf öğrencileri için 2018-2019 güz döneminde, kedi ve köpeklerin yanı sıra sahiplerinde refahını iyileştirmek için tasarım çözümleri geliştirmek amacıyla çok disiplinli bir eğitim modeli kullanılmıştır. Eğitim programına 30 tasarım öğrencisi katılmıştır. Öğrenciler seçtikleri türlere göre örneğin kediler, köpekler ve insanlar (evcil hayvan sahipleri) ve çevreye göre örneğin ev, barınak veya kampüs olmak üzere 9 takıma ayrıldılar. Ankara Üniversitesi Veteriner Fakültesinden iki öğretim elemanı tasarım öğrencilerine köpeklerin ve kedilerin duygusal ihtiyaçları hakkında dersler ve tasarım süresi boyunca da danışmanlık hizmeti vermişlerdir. Sonuç olarak, endüstriyel tasarım öğrencilerinin kedi ve köpeklerin biyolojik, duygusal ve davranışsal ihtiyaçlarını konularındaki bilinçlerinde önemli gelişmeler tespit edilmiştir. Farklı ekipler tarafından diş sağlığı, ev ortamında ilaç uygulaması, tımar gibi farklı sorunları hedefleyen fikirleri olan otuz farklı ürün tasarlanmıştır. Son ürünlerin çoğu Veteriner Fakültesi öğretim üyeleri tarafından iyi (75-79) ve olağanüstü (90-100) arasında puanlanmıştır. Bu çalışmanın sonuçları Multidisipliner eğitim ile farklı meslekler arası bilgi alışverişinin, hayvanlarda yaşam kalitesini iyileştirmek için ürün geliştirme başarısı üzerinde önemli bir etkiye sahip olduğunu göstermiştir. Cats and dogs have been living with humans for centuries in various conditions and for various reasons. Various factors such as different housing conditions, owner’s expectations and attitudes may affect the well-being of domestic animals. It is the responsibility of Veterinarians to ensure that the environment meets their needs, which further determines the welfare levels of animals. In order to meet the needs of different pets, the products used for pets should be designed in line with these needs. It can be suggested that products that fully meet the needs of pets are possible only with a multidisciplinary education model including design and veterinary behavior. In this study, a multidisciplinary education model was used for the 3rd-grade industrial design students at the Department of Industrial Product Design, Middle East Technical University in the autumn 2018-2019 Semester to develop design solutions for improving the well-being of cats and dogs as well as their owners. 30 design students attended the program. They divided into 9 teams according to the species, and environment they chose. Two lecturers from the Faculty of Veterinary Medicine gave lectures about the emotional needs of dogs and cats to the design students and supervised them during the design process. As a result, significant improvements were detected in the awareness of the industrial design students of biological, emotional and behavioral needs of cats and dogs. Thirty different products with ideas targeting different problems such as dental health, drug application, grooming were designed by different teams. Most of the end products were scored between good (75-79) and outstanding (90-100) by the instructors from the Faculty of Veterinary Medicine. The results of this study show that multidisciplinary education and the exchange of information between different professions have a significant impact on product development success to improve the quality of life in animals.

  • Effects of commercial aldehydes from green leaf volatiles (green odour) on rumen microbial population and fermentation profile in an artificial rumen (Rusitec)

    by Ahu Demirtas, Hakan Ozturk, Mert Sudagidan, Erhan Keyvan, Orhan Yavuz, Ozlem Yildiz Gulay, Saad Ahmed Adam Musa