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Öğe An Investigation on the Dna Binding Activities of Melamine, Cyanuric Acid and Uric Acid(Editura Acad Romane, 2021) Şenol, Ali; Devrim, Alparslan Kadir; Sudagidan, Mert; Özalp, Veli CengizMelamine can be added to various foods such as milk, milk powder, baby food, pet, and livestock feed for cheating purposes due to its high nitrogen content. Regarding its usage in food products, there is a need to investigate its possible interactions with DNA. Thus, this study aimed to investigate the interactions of melamine and its metabolized products, cyanuric acid and uric acid with genomic DNA, isolated from eukaryotic (calf thymus) and prokaryotic (Staphylococcus aureus) sources. UV-absorbance spectrophotometry, fluorescence spectrophotometry, and agarose gel electrophoresis techniques were used to evaluate these interactions. The five different concentrations of melamine, cyanuric acid, and uric acid were incubated with fixed DNA concentration and it was determined that the test compounds interacted with the DNA molecules. The data obtained by UV-absorbance and fluorescence spectrophotometry techniques revealed an increase in wave peaks observed with the increasing substance concentration. After the obtained data of the aforementioned techniques were evaluated together, it was concluded that melamine, cyanuric acid, and uric acid bonded to the eukaryotic and prokaryotic genomic DNA materials via groove binding.Öğe COMPARISON OF SOME COPPER COMPOUNDS IN TERMS OF THEIR INTERACTIONS WITH DNA USING AGAROSE GEL ELECTROPHORESIS, UV-ABSORBANCE AND FLUORESCENCE SPECTROPHOTOMETRY TECHNIQUES(Malaysian Society for Biochemistry and Molecular Biology, 2023) Akanbong, Elisha Apatewen; Devrim, Alparslan Kadir; Şenol, Ali; Sudagidan, MertIn this study, to investigate the interaction of genomic DNA with some copper compounds (CuSO4, CuCO3, and CuCl2) at various concentrations (1000 ?M, 500 ?M, 250 ?M, 125 ?M and 62.5 ?M); UV-absorbance spectrophotometry, agarose gel electrophoresis, and fluorescence spectrophotometry techniques were used. When the UV-spectrophotometry data were examined within the wavelength range of 220-320 nm, the hyperchromic effect of CuCl2 was evaluated to be proportional to its concentrations. Within the wavelength range, the copper compounds produced their strongest hyperchromic effect on the DNA at 1000 ?M. When the fluorescent spectrophotometry data were evaluated, the hypochromic effect of CuCl2 within the wavelength range of 400-700 nm was determined at 1000 ?M. CuSO4 showed a hypochromic effect at concentrations above 62.5 ?M. Also, it was observed that CuCO3 did not interact with DNA. According to the agarose gel electrophoresis findings, the copper compounds investigated decreased DNA band intensity as their concentrations increased. It was observed that the most significant decrease in band intensity was caused by CuCl2 at 1000 ?M. Again, it was observed that the copper compounds did not cause any cleavage in the genomic DNA within the concentration range 62.5-1000 ?M. Consequently, the copper compounds bind to DNA, most probably by non-intercalative mode. In this regard, they could have the potential to be used in the development of new therapeutic agents. Thence, conducting further studies on the interaction of the copper compounds with DNA, their possible DNA uncoiling activities, and also the investigation of these compounds in cancer cell lines will provide useful results. © 2023 Malaysian Society for Biochemistry and Molecular Biology. All rights reserved.Öğe COMPREHENDING COVID-19: IMMUNOPATHOGENIC MECHANISMS OF CYTOKINE ACTION(2021) Akanbong, Elisha; Devrim, Alparslan Kadir; Şenol, Ali; Devrim, TubaCytokine release syndrome (CRS) or cytokine storm is as a result of the excess production of pro-inflammatory cytokines which is due to the disproportionate response of the immune system which can be instigated by SARS-CoV-2. COVID-19 which is caused by SARSCoV- 2 has a correlation with cytokines. SARSCoV- 2 instigates the production of IL-1 by ubiquitous macrophages and mast cells. IL-1 tends to influence the production of IL-6 and TNF-?. The progression of COVID-19 severity influences the level of certain cytokines such as IL-6. IL-6 is the cytokine chiefly responsible for the occurrence of CRS. CRS is the cause of COVID-19-related complications and the main cause of COVID-19-related deaths. Despite the data reported in the literature so far, the relationship between SARS-CoV-2 and cytokines has not been fully elucidated. The aim of the present review is to examine the relationship in question. Targeting cytokines during COVID-19 treatment has the potential to increase patient survival and reduce COVID-19-related deaths. It is concluded that focusing on the mechanisms of cytokine release and the effects of released cytokines, especially examining the effects on T lymphocytes and IFN-? production in COVID-19 disease, may help reduce the lethal effects of the disease.Öğe Effect of Gingko Biloba Extract (Egb761) Supplementation onHemato-Biochemical Parameters Following Acute TreadmillExercise in Rats(2021) Çınar, Yasemin; Kabakçı, Ruhi; Şenol, AliThis study was aimed to investigate the effect of Gingko biloba extract (EGb761) on hemato biochemical parameters following acute treadmill exercise in rats. Thirty-two male rats were dividedinto four groups with equal number of rats. The animals of control and exercise groups orallyreceived 2 cc/kg bw 0.9% saline while EGb761 and EGb761+exercise groups received 100 mg/kgbw EGb761 by oral gavage for 5 days/week for 4 weeks. On the last day of experiment, theanimals of the exercise groups were promoted to acute exhaustive exercise, and blood sampleswere collected by intracardiac puncture from all rats. Following the hematological analysis, plasmasamples were separated for biochemical analysis. The results showed that exercise, EGb761supplementation or both did not lead to alteration on red blood cells (RBC), packed cell volume(PCV), hemoglobin (HGB), mean corpuscular hemoglobin (MCH), and mean corpuscularhemoglobin concentration (MCHC) (P>0.05). However, acute exhaustive exercise reduced meancorpuscular cell volume (MCV) in rats while increased red cell distribution width (RDW) (P<0.05). Inaddition, plasma alanine aminotransferase (ALT) activity, total cholesterol, and total protein levelsdid not change in any group (P>0.05), and alkaline phosphatase (ALP) activity was significantlyincreased in exercise groups while glucose and triglyceride levels were decreased (P<0.05). Inconclusion, our results showed that acute exhaustive exercise affected MCV and RDW values,plasma ALP activity, glucose, and triglyceride levels. Gingko biloba extract supplementationameliorated only the exercise-induced changes in ALP activity and RDW value. Therefore, it issuggested that the effects of usage after exercise or different doses of EGb761 should beinvestigated in the future comprehensive studies.Öğe Effects of free capric acid, lauric acid, and coconut oil supplementation on performance, carcass, and some blood biochemical parameters of broiler chickens(2023) Demirci, Mehmet; Evci, Şevket; Karslı, Mehmet Akif; Şenol, AliIn this study, it was aimed to investigate the effects of the addition of free capric (decanoic, C10:0) and lauric (dodecanoic, C12:0) acids and coconut (Cocos nucifera) oil to the broiler diets on performance, carcass yield, internal organ weights and some blood parameters. A total of 144 day-old broiler chicks (Ross 308) were used in the study, and four main groups were formed with four subgroups containing equal number of chicks. The control (C) group was fed with basal diet without any supplementation and the experimental groups were fed with 0.4% free capric acid (CA)-, lauric acid (LA)-, and coconut oil (CO)-supplemented basal diets and feeding was continued for 42 days. At the end of the process, the total average live weight (LW) of C, CA, LA, and CO groups reached 3048.63, 3009.88, 3052.13, and 3060.71 g, respectively. Moreover, average live weight gains (LWG) of groups were 3004.34, 2965.53, 3007.84, and 3015.82 g; average feed intakes (FI) were 4427.34, 4405.15, 4353.89, and 4375.54 g, and feed efficiency (FE) were 1.48, 1.50, 1.46, and 1.46. Average LW, LWG, FI, and FE values were similar at the end of the experiment (p > 0.05). From the carcass parameters, relative carcass rates and also carcass, bursa of Fabricius, pancreas, spleen, and gizzard weights were similar between the groups (p > 0.05). However, there were statistically significant changes in heart and liver weights between the groups; they were the lowest in the CA group and the highest in the LA group. There were no statistically significant differences between the groups in terms of serum biochemical parameters (p > 0.05). However, there were significant differences between the groups in terms of serum CK, Ca, and P values, and these values were the highest in the group fed with coconut oil. In conclusion, it is possible to state that the use of free capric acid, lauric acid, and coconut oil at the rate of 0.4% did not cause any significant difference in broiler performance, carcass, and serum biochemical parameters, but also no adverse effects were observed. It has been shown that feeding with coconut oil can significantly increase dissolved calcium and phosphorus in serum and affect their metabolism in the body and can also be an important antioxidant food additive for broiler with its effect of increasing the total antioxidant status (TAS) value.Öğe Farelerde monokrotalin ile indüklenen hepatik hasarda apoptotik belirteçlerin ekspresyon seviyelerindeki değişikliklerin incelenmesi(Kırıkkale Üniversitesi, 2024) Şenol, Ali; Devrim, Alparslan Kadir; Çınar, MiyaseBu çalışmanın amacı, canlılarda hepatotoksisiteye neden olduğu bilinen pirolizidin alkaloidlerinden monokrotalin (MCT) kaynaklı hepatik hasarın biyokimyasal ve moleküler düzeyde meydana getirdiği değişikliklerin incelenmesidir. Bu amaçla 30 adet erkek BALB/c faresi; kontrol, akut toksisite ve subakut toksisite olmak üzere üç gruba ayrıldı. Kontrol grubuna %0,9 salin, akut toksisite grubuna 120 mg/kg tek doz MCT, subakut toksisite grubuna 5 gün arayla toplam 3 kez 120 mg/kg MCT uygulandı. Tüm uygulamalar intragastrik olarak gerçekleştirildi. Deneme sonunda plazma AST, ALT ve GGT aktiviteleri ile TBIL, TCHO ve TP düzeyleri belirlendi. Ayrıca deney sonlandırılmasında toplanan karaciğer dokuları, oksidatif stres belirteçlerinden TAK, TOK ve OSİ düzeylerinin belirlenmesi, histopatolojik incelemeler ve moleküler tekniklerde kullanılmak üzere total RNA'nın izole edilmesi amacıyla kullanıldı. Yapılan incelemelerde kontrol grubuna göre deneme gruplarında ALT (P?0,05) ve GGT (P<0,001) aktiviteleri ile TBIL (P<0,001) düzeylerinin istatistiksel açıdan önemli düzeyde, AST aktiviteleri ve TCHO düzeylerinin sayısal olarak arttığı (P>0,05), TP düzeylerinin ise önemli düzeyde azaldığı (P<0,001) belirlendi. Karaciğer doku homojenatlarında oksidatif stres parametrelerinden TOK (P<0,001) ve OSİ (P>0,05) düzeylerinin kontrol grubuna kıyasla deneme gruplarında artış gösterdiği tespit edildi. Total antioksidan kapasite düzeylerinin ise kontrol grubuna göre akut toksikasyon grubunda sayısal olarak azaldığı (P>0,05), subakut toksikasyon grubunda ise önemli düzeyde arttığı (P<0,05) belirlendi. Ayrıca doku homojenatlarında Bcl-2, Bax ve Kaspaz-3 protein düzeyleri ELISA tekniği ile belirlendi. Deneme gruplarında pro-apoptotik markır Bax (P>0,05) ile Kaspaz-3 (P<0,05) protein düzeylerinde artma, anti-apoptotik markır Bcl-2 (P<0,001) düzeylerinde ise azalmaların olduğu görüldü. Aynı markırların qPCR ile gen ekspresyon düzeylerindeki değişikliklerin ELISA sonuçları ile uyumlu olduğu ancak istatistiksel açıdan önemli düzeyde olmadığı belirlendi (P>0,05). Moleküler düzeyde yapılan qPCR analizinin yanında aynı prensibe dayanan PCR array analizi ile de apoptotik belirteçler, JAK/STAT proteinleri, STAT etkileşimli transkripsiyon faktörler, hücre döngüsü, proliferasyonu, büyümesi ve/veya onarımı, akut faz tepkisi ile inflamatuar yanıttan sorumlu çok sayıda gen ekspresyonu, eş zamanlı olarak taranarak kontrol grubuna göre artan ya da azalan genlerin eksresyon profili tespit edildi. Monokrotalinin sebep olduğu karaciğer hasarının hücresel boyutta incelenmesi için yapılan mikroskobik incelemelerde, deneme gruplarında hasar belirteçlerinde değişikliklerin olduğu ve akut toksikasyon grubundaki değişikliklerin daha şiddetli düzeyde olduğu görüldü. Sonuç olarak MCT'nin sebep olduğu hepatik hasar sürecinde karaciğer enzim aktivitelerinin ve oksidatif stres mekanizmasının olumsuz yönde etkilendiği, ayrıca gerçekleştirilen ELISA ve qPCR analizleri ile de hem protein hem de gen düzeylerinde elde edilen Bcl-2, Bax ve Kaspaz-3 ekspresyonlarının önemli değişiklikler sergilediği anlaşıldı. Ayrıca, PCR array tekniği ile de incelenen hepatik hasar süreci ile ilişkili moleküler yolaklarda ekspresyon değişiklikleri gen panelleri seviyesinde belirlenerek potansiyel biyokimyasal ve patolojik belirteçler ortaya konuldu. Elde edilen verilerin yeni çalışmaların planlanması için önemli veriler sunduğu kanaatine varıldı.Öğe Melamin, siyanürik asit ve ürik asidin DNA ile etkileşimlerinin incelenmesi(Kırıkkale Üniversitesi, 2020) Şenol, Ali; Devrim, Alparslan KadirDNA molekülü, çift sarmallı yapıya sahip olması nedeni ile ilaçlar, metal kompleksleri ve birçok molekül için potansiyel bağlanma bölgeleri taşımaktadır. Bağlanmak için DNA'yı hedef olarak seçen söz konusu moleküllerin gerek zararsız hale getirilebilmeleri gerekse olası ilaç etkinliklerinin artırılması için moleküller arası etkileşim şekillerinin aydınlatılması oldukça önemlidir. Azotlu organik bir bileşik olan melamin, metabolizmada ürik asit ve siyanürik asit gibi çeşitli metabolitlere dönüşebilmektedir. Melamin ve metabolitlerinin gastrointestinal sistemde emildiği ve hayvanlarda nefrolitiazis, kronik böbrek iltihabı ve mesane karsinomu dahil olmak üzere çeşitli zararlı etkilere sebep olabildiği ileri sürülmüştür. Bu çalışmada, yüksek azot içeriği sebebiyle süt, süt tozu, bebek mamaları, pet ve çiftlik hayvan yemleri gibi çeşitli gıdalara hile amaçlı katılan melamin ve metabolize olan melaminden oluşan siyanürik asit ve ürik asidin ökaryotik (sığır timus dokusu) ve prokaryotik (Staphylococcus aureus bakteri kültürü) kaynaklardan izole edilen genomik DNA ile olan etkileşimlerinin incelenmesi amaçlandı. Söz konusu etkileşimlerin değerlendirilmesinde UV-absorbans spektrofotometri, floresans spektrofotometri ve agaroz jel elektroforezi tekniklerinden yararlanıldı. Sabit DNA konsantrasyonu ile inkübe edilen, beş farklı konsantrasyondaki melamin, siyanürik asit ve ürik asit çözeltilerinin gerçekleştirilen analizleri neticesinde söz konusu bileşiklerin DNA molekülleri ile etkileşim içerisinde olduğu belirlendi. UV-absorbans ve floresans spektrofotometri analizleri ile elde edilen grafiklerde, artan madde konsantrasyonuna karşın dalga piklerinde de artış gözlendi. Agaroz jel elektoroforez analizleri ile elde edilen jel görüntülerinin piksel ölçümü yapıldığında etkileri incelenen metabolitlerin DNA bant hacminde azalmaya sebep olduğu ve bu durumun, melamin ile hazırlanan kombinasyonlarda daha da belirgin hale geldiği görüldü. Elde edilen bulgular değerlendirildiğinde, melamin, siyanürik asit ve ürik asidin incelenen ökaryotik ve prokaryotik genomik DNA materyallerine groove bağlanma ile bağlandığı sonucuna varıldı. Anahtar Kelimeler: DNA, melamin, siyanürik asit, ürik asit, UV-absorbans, floresans spektrofotometri, agaroz jel elektroforeziÖğe Protective Effect of Krill Oil Against Gentamicin Induced Oxidative Stress Mediated Nephrotoxicity in Rats(2022) Şahin, Yaşar; Alçığır, Mehmet Eray; Şenol, Ali; Özden, Hüseyin; Ekici, Hüsamettin; Yıldırım, Ebru; Çınar, MiyaseThis study aimed to evaluate the protective effect of krill oil against nephrotoxicity caused by gentamicin. Distilled water was given orally to the control and second groups (GI) for seven days while 500 mg/kg krill oil was given to the third (GII), fourth (GIII) groups. In addition, isotonic saline was administered subcutaneously to the control and GIII groups throughout the study, while 80 mg/kg gentamicin was administered to the GI, and GII groups. Alanine aminotransferase (ALT) and gamma glutamyltransferase (GGT) peptidase, total cholesterol, urea, and creatinine levels in plasma and, malondialdehyde (MDA) and total antioxidant status (TAS) levels in both plasma and kidney tissue supernatant were evaluated. Histopathological changes in tubules and glomeruli and vascular changes were evaluated by scoring. Urea level and ALT activity were found to be significantly lower in the GII and GIII groups compared to the GI group (p<0.001; p?0.001). As a result, it was observed that degenerative damage and glomerular changes in the tubule at the histological level mediated by oxidative stress were consistent with the increase in ALT, urea, and MDA levels. In this respect, it is suggested that krill oil can be used as a nephroprotective food supplement to contribute to treatment in cases of toxicity.Öğe Protective Effect of Silymarin and Boric Acid Against Isoproterenol-Induced Myocardial Infarction in Mice(2022) Şahin, Yaşar; Alçığır, Mehmet Eray; Bakar-Ateş, Filiz; Ekici, Hüsamettin; Şenol, Ali; Atıcı, Enes Gazi; Yıldırım, EbruThis study aimed to compare the protective effects of separate and combined use of silymarin and boric acid against myocardial infarction induced by isoproterenol. Distilled water was given orally by gavage to the GI and GII groups for fourteen days. The GIII group was received silymarin (100 mg/kg), while the GIV group was given boric acid (100 mg/kg) for 14 days. In the last group, both silymarin and boric acid were given orally (gavage) for fourteen days. On the thirteenth and fourteenth days of the study, while isotonic water was applied to the GI group, isoproterenol (85 mg/kg) was applied to the other groups subcutaneously. Plasma ALT, AST, Ca, CK, CHO, TP, Ing P, IL-6, IL-12, PAL-1, and sPLA2 parameters were evaluated. Histopathological examination was performed on the heart, lung, liver, kidney, spleen, cerebrum, and cerebellum tissues taken from mice. The CK level was found to be significantly lower in the GIII and GV groups compared to the GII group (P<0.05). As a result, the increases shown in the plasma AST and CK activities caused due to the myocardial damage induced by isoproterenol were decreased in the silymarin and boric acid applied groups. Therefore it was thought that silymarin and boric acid may contribute to protection against myocardial infarction.Öğe The effect of krill oil on Wnt/ß-catenin signaling pathway in acetaminophen-induced acute liver injury in mice(De Gruyter Open Ltd, 2023) Şahin, Yaşar; Devrim, Alparslan Kadir; Alçiğir, Mehmet Eray; Şenol, Ali; Ekici, Hüsamettin; Devrim, Tuba; Sudağidan, MertObjectives: This study investigated the effect of krill oil (KO) on liver damage caused by acetaminophen (APAP). Methods: In the present study, the control and APAP groups were given distilled water by gavage for 14 days. In addition, the KO and APAP+KO groups were given 500 mg/kg krill oil by gavage for 14 days. At the end of 14 days, 0.9 % sodium chloride solution (saline solution) administration was applied intraperitoneally to the control and KO groups. Meanwhile, 220 mg/kg acetaminophen was administered to the APAP and APAP+KO groups. While some biochemical parameters in plasma were examined, some oxidative stress parameters in plasma and liver tissue were evaluated. Apoptotic and inflammatory responses of some primer sequences determined by quantitative Real-Time PCR (qPCR) in liver tissue. After histopathological examination of liver tissue, immunohistochemical analysis was performed with Wnt inhibitory factor-1 (Wif-1), beta-catenin (ß-Catenin), and 8-hydroxy-2'-deoxyguanosine (8-OHdG). Results: The Wif-1 positivity in hepatocytes increased significantly in the APAP group (5.29 ± 0.71) compared to the control (1.14 ±0.51), and KO (2.14 ± 0.55) groups (p<0.001). The 8-OHdG positivity in hepatocytes increased significantly in the APAP group (19.57 ± 0.58) compared to the control (0.43 ± 0.20), KO (3.57 ± 0.48), and APAP+KO (4.00 ± 2.53) groups (p<0.001).Conclusions: As a result, krill oil could be used as a nutritional supplement to protect the liver against acetaminophen-induced liver injury. © 2023 De Gruyter. All rights reserved.Öğe The effect of krill oil on Wnt/ß-catenin signaling pathway in acetaminopheninduced acute liver injury in mice(Walter De Gruyter Gmbh, 2023) Şahin, Yaşar; Devrim, Alparslan Kadir; Alcigir, Mehmet Eray; Şenol, Ali; Ekici, Hüsamettin; Devrim, Tuba; Sudagidan, MertObjectives: This study investigated the effect of krill oil (KO) on liver damage caused by acetaminophen (APAP). Methods: In the present study, the control and APAP groups were given distilled water by gavage for 14 days. In addition, the KO and APAP+KO groups were given 500 mg/kg krill oil by gavage for 14 days. At the end of 14 days, 0.9 % sodium chloride solution (saline solution) administration was applied intraperitoneally to the control and KO groups. Meanwhile, 220 mg/kg acetaminophen was administered to the APAP and APAP+KO groups. While some biochemical parameters in plasma were examined, some oxidative stress parameters in plasma and liver tissue were evaluated. Apoptotic and inflammatory responses of some primer sequences determined by quantitative Real-Time PCR (qPCR) in liver tissue. After histopathological examination of liver tissue, immunohistochemical analysis was performed with Wnt inhibitory factor-1 (Wif-1), beta-catenin (ss-Catenin), and 8-hydroxy-2'-deoxyguanosine (8-OHdG). Results: The Wif-1 positivity in hepatocytes increased significantly in the APAP group (5.29 +/- 0.71) compared to the control (1.14 +/- 0.51), and KO (2.14 +/- 0.55) groups (p<0.001). The 8-OHdG positivity in hepatocytes increased significantly in the APAP group (19.57 +/- 0.58) compared to the control (0.43 +/- 0.20), KO (3.57 +/- 0.48), and APAP+KO (4.00 +/- 2.53) groups (p<0.001). Conclusions: As a result, krill oil could be used as a nutritional supplement to protect the liver against acetaminopheninduced liver injury.Öğe The effect of using different litter materials in broiler rearing on performance, carcass yield, antioxidant status, some litter parameters, and coccidiosis oocysts(Tubitak Scientific & Technological Research Council Turkey, 2023) Şen, Gökhan; Oktay, Mehmet Naci; Evci, Şevket; Gökpınar, Sami; Şenol, AliThe aim of this study was to determine the effects of various mixtures of different litter materials containing wood shaving and barley straw on body weight gain, feed consumption, feed efficiency, carcass yield, antioxidant state, litter quality, and coccidio oocysts in broilers rearing. For this purpose, a total of 120, 0-day-old Ross 308 broilers were assigned to 3 groups with 4 replicates. Wood shaving, barley straw, and wood shaving + barley straw group had 10 chicks in each replicate, a total of 40 chicks in each group. When the overall period of the study was examined, it was determined that the feed conversion ratio (FCR) of the barley straw group was higher than other groups in the second half of the study (p < 0.05). It was observed that while nitric oxide (NO) level was higher in the wood shaving + barley straw group, enzymatic antioxidants could be more functional in the wood shaving group (p < 0.05). As a result, it has been concluded that the use of wood shaving and barley straw separately or mixed in equal proportions as litter will have a similar effect on performance and litter quality, whereas wood shaving will positively influence on the antioxidant status.Öğe The relationship of leptin and thyroid hormones with milk yield and some fertility parameters in Simmental dairy cows during transition period(Tubitak Scientific & Technological Research Council Turkey, 2021) Duru, Özkan; Devrim, Alparslan Kadir; Macun, Hasan Ceyhun; Duru, Sibel Yasa; Şenol, AliIn this study, transition period cows were used to test the hypothesis that serum levels of leptin and thyroid hormones would correlate the production efficiency such as milk yield, body condition score, and fertility in dairy cows raised under the same controlled conditions. The study comprised 37 Simmental cows, which were 3 years old and between 257-265 days of gestation. Serum levels of leptin, T3, T4, FT3, and FT4 hormones were measured in blood samples obtained from the animals, which were in the period of 3 weeks before and 3 weeks after delivery. Prepartum serum leptin levels were significantly (p < 0.05) lower in cows having increased milk production compared to the first lactation peak value. Also, postpartum serum FT3 levels were significantly (p < 0.05) lower in cows having milk yield of >= 30 kg. Leptin levels were found to be inversely related with milk production and fertility. FT3 levels exhibited a negative correlation with milk production and similarly T3 levels showed an inverse correlation with body condition score. The present study proposed that routine monitoring of leptin and thyroid hormones would be useful for the reproductive management of cows with breeding problems.
