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Öğe Acromegaly is associated with high fibroblast growth factor-21 levels(Springer, 2019) Yurekli, B. S.; Kutbay, N. O.; Aksit, M.; Suner, A.; Simsir, I. Y.; Seckiner, S.; Kocabas, G. U.; Bozkaya, G.; Saygili, F.PurposeFibroblast growth factor-21 (FGF-21) is a member of fibroblast growth factor family. Both growth hormone (GH) and FGF-21 take place in the regulation of glucose and lipid metabolism. We aimed to investigate FGF-21 levels in acromegaly which is characterized by excess GH levels and is associated with comorbidities and altered body composition.MethodsWe studied 43 subjects (21 females and 22 males, mean age of 50.012.8) with acromegaly. The control group consisted of 40 gender- and age-matched subjects (25 females and 15 males, mean age of 48.88.8). Acromegaly patients were classified into two groups; active acromegaly (AA; n=26) and controlled acromegaly (CA; n=17). Metabolic, anthropometric and laboratory values of subjects were recorded. FGF-21 level was measured by ELISA assay.Results Median FGF-21 levels were significantly higher in acromegaly group compared to control group (85.5 vs. 59.0pg/mL, p=0.02, respectively). In the multiple regression model, FPG, A1c, HOMA-IR, glucose intolerance, BMI, visceral fat, hs-CRP, presence of hypertension, dyslipidemia and acromegaly were included as independent variables to explain variability of plasma FGF-21 levels in whole study group. The presence of acromegaly was the only determinant of increased FGF-21 levels in the whole study group ( coefficient=0.253, p=0.006).Conclusion FGF-21 levels were increased significantly in acromegaly group. Increased FGF-21 levels were significantly and independently associated with the state of acromegaly. Acromegaly may also be a FGF-21 resistance state independent from insulin resistance, glucose intolerance, obesity, hypertension and dyslipidemia.Öğe Assessment of osteoprotegerin and RANKL levels and several cardiovascular risk scoring systems in acromegaly(Springer Science and Business Media Deutschland GmbH, 2023) Kocabas, G.U.; Yurekli, B.S.; Simsir, I.Y.; Ozgur, S.; Aksit, M.; Bozkaya, G.Purpose: The OPG/RANKL (osteoprotegerin/receptor activator of nuclear factor kappa-B) system, which plays a crucial role in bone metabolism, is also associated with vascular calcification. Acromegaly is characterized by excessive secretion of growth hormone and insulin-like growth factor, and studies have demonstrated an elevated risk of cardiovascular disease in individuals with acromegaly. In this study, our objective was to investigate the relationship between OPG/RANKL and various cardiovascular risk scoring systems. Methods: We recruited 44 consecutive acromegaly patients and 41 healthy controls with a similar age and gender distribution for this study. Results: While RANKL levels were significantly higher in the acromegaly group compared to the controls, OPG levels were not found to be significantly different between the two groups. Furthermore, within the acromegaly group, RANKL levels were significantly higher in patients with active acromegaly compared to those with controlled acromegaly. Osteoprotegerin levels showed a positive correlation with the Framingham risk score (FRS) in the acromegaly group. Linear regression analysis revealed an association of OPG with FRS (adjusted R 2 value of 21.7%). Conclusion: OPG and RANKL may serve as potential markers for assessment of cardiovascular calcification and prediction of the cardiovascular risk status in acromegalic patients. © 2023, The Author(s), under exclusive licence to Hellenic Endocrine Society.Öğe Broilers respond to cooler ambient temperatures after temperature acclimation during incubation and early postnatal age(Poultry Science Assoc Inc, 2013) Aksit, M.; Yalcin, S.; Siegel, P. B.; Yenisey, C.; Ozdemir, D.; Ozkan, S.Temperature acclimation, either during the incubation or the early growing period, has been suggested as an effective method to improve thermotolerance of broilers to cooler rearing temperatures. We compared the response of broilers from younger (Y) and older (O) breeder flocks to cooler rearing temperatures after temperature acclimation during incubation and early posthatch. Eggs were exposed to either a control incubation temperature (37.6 degrees C) or a cooler temperature (36.6 degrees C; ITcool) for 6 h (from 1000 to 1600 h) daily from d 10 to 18 of incubation. From d 22 to 42, chicks were reared at a control temperature (RTcont), a cooler temperature (17 +/- 2 degrees C; RTcool), or at a cooler temperature after acclimation of chicks to cooler temperatures by exposing them to 17 +/- 2 degrees C for 6 h on d 5 posthatch. The ITcool conditions reduced mortality and mortality due to ascites of O broilers reared under cooler temperatures from d 22 to 42. Early age acclimation to cooler temperatures did not support thermotolerance of broilers. Regardless of IT, the RTcool broilers from Y gained more weight but had poorer feed conversion than RTcont. Repeated cooler temperatures applied during incubation and early postnatal stage disturbed homeostasis and energy balance of broilers from O breeders.Öğe Circulating insulin-like peptide 5 levels and its association with metabolic and hormonal parameters in women with polycystic ovary syndrome(Springer, 2019) Bicer, M.; Alan, M.; Alarslan, P.; Guler, A.; Kocabas, G. U.; Imamoglu, C.; Aksit, M.; Bozkaya, G.; Isil, A. M.; Baloglu, A.; Aslanipoiur, B.; Calan, MehmetPurposeInsulin-like peptide 5 (INSL5) is a gut peptide hormone that is a member of relaxin/insulin superfamily. Growing evidence implicates the crucial role of the peptide in some metabolisms including food intake, glucose homeostasis and reproductive system. Polycystic ovary syndrome (PCOS) is involved in both reproductive and metabolic issues. The aim of the study was determination of circulating levels of INSL5 alteration in women with PCOS and evaluation of the relationship between INSL5 and hormonal-metabolic parameters as well as carotid intima media thickness (cIMT).MethodsA total of 164 subjects were recruited in this cross-sectional study (82 women with PCOS and 82 age- and BMI-matched controls). Circulating INSL5 levels were assessed via ELISA method. High-resolution B-mode ultrasound was used to measure cIMT. The hormonal and metabolic parameters of the recruited subjects were determined.ResultsCirculating INSL5 levels were significantly elevated in women with PCOS compared to controls (27.637.74 vs. 19.90 +/- 5.85ng/ml, P<0.001). The mean values of INSL5 were significantly higher in overweight subjects compared to lean weight subjects in both groups. The women with PCOS having insulin resistance have increased INSL5 compared to those of PCOS subjects without insulin resistance. INSL5 is associated with insulin resistance, BMI, luteinizing hormone and free androgen index. Multivariate logistic regression analyses revealed that the odds ratio for having PCOS in the highest tertile of INSL5 was higher than in the lowest tertile.Conclusions PCOS subjects exhibited an elevation in circulating INSL5 levels along with a link between INSL5 level induction and metabolic-hormonal parameters.Öğe Effect of manipulation of incubation temperature on fatty acid profiles and antioxidant enzyme activities in meat-type chicken embryos(Oxford Univ Press, 2012) Yalcm, S.; Bagdathoglu, N.; Yenisey, C.; Siegel, P. B.; Ozkan, S.; Aksit, M.Eggs (n = 1,800) obtained from Ross broiler breeders at 32 and 48 wk of age were incubated at either a constant temperature of 37.6 degrees C throughout (T1), or the temperature was reduced for 6 h to 36.6 degrees C each day during embryonic age (EA) 10 to 18 (T2). Yolk sac, liver, and brain fatty acid profiles and oxidant and antioxidant status of liver and brain were measured at EA 14, 19, and day of hatch (DOH). Fatty acid profiles of yolk sac, liver, and brain were influenced by age of breeder with significant breeder hen age x incubation temperature interactions. At EA 14, higher levels of 20:4n-6 and 22:6n-3 had been transferred from the yolk sac to T2 embryos from younger than older breeders, whereas for T1 and T2 embryos, yolk sac 20:4n-6 and 22.6n-3 values were similar for older breeders. Accumulation of 20:4n-6 and 22:6n-3 fatty acids in the liver of T1 and T2 embryos from younger breeders was similar; however, T2 embryos from older breeders had higher liver levels of 20:4n-6 and 22:6n-3 than T1 embryos. At EA 19, liver nitric oxide levels were higher for T2 embryos from younger breeders than those from breeders incubated at T1. Brain catalase levels of T2 embryos from younger breeders were higher than those from older breeders at DOH. Thus, changes in fatty acid profiles and catalase and nitric oxide production of brain and liver tissues resulting from 1 degrees C lower incubation temperature from EA 10 to 18 reflect adaptive changes.Öğe Effect of temperature manipulation during incubation on body weight, plasma parameters, muscle histology, and expression of myogenic genes in breast muscle of embryos and broiler chickens from two commercial strains(Taylor & Francis Ltd, 2022) Yalcin, S.; Aksit, M.; Ozkan, S.; Hassanzadeh, M.; Bilgen, G.; Helva, I. B.; Izzetoglu, G. T.1. This study evaluated the effect of a higher incubation temperature on body weight, plasma profile, histology and expression of myogenin (MYOG), insulin-like growth factor-I (IGF-I) and vascular endothelial growth factor A (VEGFA) genes in breast muscle of embryos and broilers from two commercial strains. 2. A total of 784 eggs from Ross 308 and Cobb 500 broiler breeder flocks were used. Half of the eggs per strain were incubated at control temperature (37.8 degrees C), whereas the other half were exposed to heat treatment (HT) of 38.8 degrees C between embryonic day (ED) 10 and 14, for 6 h/day. Embryos and chicks were sampled on ED 19 and at hatch. A total of 480, one-day-old chicks per strain and incubation temperature were reared up to 42 d post-hatch. 3. The HT increased hatch weight of Ross chicks and 42-d body weight of broilers from both strains. Lower plasma triacylglycerol levels were measured for HT embryos and broilers on ED 19 and 42 d post-hatch, respectively. HT reduced plasma T-3 levels in Ross embryos and broilers for the same periods. Hepatic TBARS concentrations were elevated by HT compared to the control incubation. 4. The HT reduced breast muscle VEGFA gene expression of Cobb embryos on ED 19, whereas expression was stimulated in day-old chicks. At 42 d post-hatch, fibre area was increased by HT regardless of strain. Compared to the control incubation, HT increased the breast yield of Ross broilers and leg yield of Cobb. Ross-HT broilers had a higher pH at 24 h after slaughter and better water holding capacity than Cobb-HT broilers. 5. These results suggested that HT increased body weight, fibre area, IGF-I gene expression and lowered plasma triacylglycerol levels of broiler chickens from both strains at 42 d. However, HT influenced the expression of VEGF-A and MYOG genes and meat quality differently between the broiler strains.Öğe Effects of cold temperature and vitamin E supplementation on oxidative stress, Troponin-T level, and other ascites-related traits in broilers(Eugen Ulmer Gmbh Co, 2008) Aksit, M.; Altan, Ozge; Karul, Aslihan Bueyuekoeztuerk; Balkaya, M.; Ozdemir, D.The present study was conducted to determine effects of low ambient temperature and dietary vitamin E supplementation on growth performance and ascites- related traits in broilers, and to assess oxidative stress status in broilers with ascites. Male broiler chicks (Ross) were randomly assigned to one of four experimental groups. Control or low temperature groups were fed a standard commercial diet with (200 mg Vitamin E/kg) or without supplemental vitamin E from 0 to 6 week of age. Low rearing temperature caused growth depression and induced the development of ascites syndrome as indicated by clinical signs and higher hemotocrit level, RV/TV ratio, and serum Troponin-T level. Ascitic broilers exhibited significantly lower SOD, CAT and GSH-Px activities, and higher MDA level suggesting the presence of oxidative stress. In spite of some decrease in ascites-induced mortality, dietary vitamin E supplementation could not improve growth performance and was not effective in protecting tissues from oxidative damage.Öğe Effects of monochromatic light on growth performance, welfare and hormone levels in broiler chickens(Eugen Ulmer Gmbh Co, 2019) Helva, I. B.; Aksit, M.; Yalcin, S.This study aimed to investigate the effect of the colour of monochromic light-emitting diode (LED) lighting on growth performance, tonic immobility duration, gait score, and hormone concentration in broilers. A total of 540 one-day-old broilers were randomly assigned into three lighting treatments: 1) 517-623 nm, 6500 K (white, WL), 2) 440 -480 nm (blue, BL), and 3) 503-540 nm (green, GL) LED light. Body weight and feed intake were recorded, weekly. The duration of tonic immobility and the gait score of the broilers were determined at d 28 and 35. Concentrations of growth hormone (GH), adrenocorticotropic hormone (ACTH) and insulin-like growth factor (IGF-1) were assayed on d 1, 7, 21 and 42. From d 14 to 42 broilers of the BL and GL groups were heavier than of the WL group. Although, there was no effect of lighting treatment on feed intake from d 0 to 21, GL and BL broilers consumed more feed than WL broilers from d 22 to 42. The duration of tonic immobility was not influenced by the LED light colour. Sex had a significant effect on tonic immobility duration. It was shorter in males than in females. There was no difference among groups in gait score at d 28. However, a better walking ability was obtained under GL on d 35. The WL broilers had the highest IGF-1 concentration on d 7. On d 42, birds under BL and GL lighting had lower ACTH concentration than under WL. The present results suggested that BL and GL improved body weight and reduced stress response of broilers. Furthermore, walking ability of broilers can be improved by GL lighting.Öğe Effects of temperature during rearing and crating on stress parameters and meat quality of broilers(Oxford Univ Press, 2006) Aksit, M.; Yalcin, S.; Ozkan, S.; Metin, K.; Ozdemir, D.Two trials were conducted to study the effects of heat stress during rearing (trial 1) and crating (trial 2) on broiler stress parameters and fear, breast meat quality, and nutrient composition. The relationships between stress parameters and meat quality traits were also determined. Trial I consisted of 3 temperature treatments from 3 to 7 wk: control (temperature was 22 degrees C); diurnal cyclic temperature (temperature was 28 degrees C from 1000 to 1700 h and 22 degrees C from 1700 to 1000 h); and constant high temperature (34 degrees C; temperature was 34 degrees C). In trial 2, broilers from the control and 34 degrees C groups in trial I were used. Broilers in each group were placed in transport cages. The 9 cages from the control group were divided into 3 groups and placed into 3 rooms at 15, 22, or 34 degrees C for 2 h. The 3 cages from the 34 degrees C group were also held in the room at WC (34-34 degrees C). Diurnal cyclic temperature had no effect on BW up to 5 wk of age. The effect of WC constant temperature on BW of broilers increased with age. Plasma levels of glucose and albumin increased by 34 degrees C, but no dramatic change in levels occurred when those broilers were crated at 34 degrees C. The heterophil:lymphocyte (H:L) was higher for the 34-34 degrees C broilers and the control broilers in the WC room than those from the 22 and 15 degrees C room. Breast muscle glycogen level decreased in broilers reared under diurnal cyclic or high temperatures. A lower pH and higher lightness (L*) and redness values and redness:yellowness were found in meat for broilers from both 34 degrees C and 34-34 degrees C groups. Higher H:L was associated with breast muscle pH according to first-order polynomial regression. The H:L had a significant effect on L* values, which were described by a second-order polynomial regression. Blood glucose level was positively correlated with L* and redness values. Duratiori of tonic immobility was neither influenced by rearing and crating temperatures nor associated with meat quality parameters.Öğe Environmental enrichment influences on broiler performance and meat quality: Effect of light source and providing perches(Eugen Ulmer Gmbh Co, 2017) Aksit, M.; Yardim, Z. Kacamakli; Yalcin, ServetThe aim of the experiment was to examine the effect of perches on performance, tibia bone parameters, fear level and meat quality of broilers under either fluorescent or monochromatic white light-emitting diodes (LED) lighting. A total of 700 one-day old mixed sexes broiler chickens (ROSS 308) were randomly assigned to one of 4 treatments: 1) Fluorescent (FL) lighting was provided without perches, 2) FL lighting was provided with perches, 3) LED (white) lighting was provided without perches and 4) LED lighting was provided with perches. Galvanised steel perches were constructed of 200 cm in length and 20 mm width and placed at 15 cm height. Perch space for each bird was 25 cm. Although body weight did not differ among treatment groups at 7 d, perching reduced body weight under LED lighting at 14 d. Lower body weight of broilers with perches was associated with impaired feed conversion at 21 d. At 42 d, while perch treatment did not significantly affect body weight, LED lighting resulted in 44 g (P=0.088) heavier body weight with improved feed conversion and increased tibia breaking strength compared to FL lighting. Tonic immobility (TI) duration, gait score, breast meat pH and lightness were similar among treatment groups. Perching increased yellowness and redness of breast meat. These results suggest that providing broilers with perches have no effect on body weight and feed consumption and conversion at 42 d. Monochromatic LED light resulted in improved feed conversion and tibia breaking strength at slaughter age without interacting with perch treatment. Therefore, light source appears to be the most important environmental factor.Öğe Exposure of embryos to cyclically cold incubation temperatures durably affects energy metabolism and antioxidant pathways in broiler chickens(Oxford Univ Press, 2014) Loyau, T.; Collin, A.; Yenisey, c; Crochet, S.; Siegel, P. B.; Aksit, M.; Yalcin, S.Cyclically cold incubation temperatures have been suggested as a means to improve resistance of broiler chickens to ascites; however, the underlying mechanisms are not known. Nine hundred eggs obtained from 48 wk Ross broiler breeders were randomly assigned to 2 incubation treatments: control I eggs were incubated at 37.6 degrees C throughout, whereas for cold I eggs the incubation temperature was reduced by 1 degrees C for 6 h daily from 10 to 18 d of incubation. Thereafter, chickens were reared at standard temperatures or under cold exposure that was associated or not with a postnatal cold acclimation at d 5 posthatch. At hatch, hepatic catalase activity and malondialdehyde content were measured. Serum thyroid hormone and triglyceride concentrations, and muscle expression of several genes involved in the regulation of energy metabolism and oxidative stress were also measured at hatch and 5 and 25 d posthatch. Cold incubation induced modifications in antioxidant pathways with higher catalase activity, but lower expression of avian uncoupling protein 3 at hatch. However, long-term enhancement in the expression of avian uncoupling protein 3 was observed, probably caused by an increase in the expression of the transcription factor peroxisome proliferator activated receptor-gamma coactivator-1 alpha These effects were not systematically associated with an increase in serum triiodothyronine concentrations that were observed only in chickens exposed to both cold incubation and later acclimation at 5 d with cold rearing. Our results suggest that these conditions of cyclically cold incubation resulted in the long-term in changes in antioxidant pathways and energy metabolism, which could enhance the health of chickens reared under cold conditions.
