Browsing by Author "Uysal, S."

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Evaluation of a Stress Model Induced by Dietary Corticosterone Supplementation in Broiler Breeders: Effects on Egg Yolk Corticosterone Concentration and Biochemical Blood Parameters
(2013) Babacanoǧlu, E.; Yalçin, S.; Uysal, S.
1. This study aimed to evaluate a stress model induced by corticosterone (CORT) supplementation in the diet of broiler breeder hens.2. A total of 60 Ross broiler breeder hens at 29 weeks of age were randomly divided into 4 groups with 15 hens each. The first group served as the control. The rest of the hens were given 1, 1.5 or 2 mg of CORT/hen/d (CORT1, CORT1.5 and CORT2, respectively) for 7 d. Concentrations of yolk CORT, plasma uric acid, glucose, cholesterol, creatine kinase, heterophil (H):lymphocyte (L) ratio and duration of tonic immobility (TI) were measured at d 3, 5 and 7 of CORT supplementation. The same measurements were repeated at 3, 5 and 7 d after CORT was withdrawn from the diet.3. There were no significant CORT dose effect on yolk CORT and plasma glucose concentrations. Higher plasma uric acid and H:L ratio was obtained for CORT1.5 and CORT2 than for CORT1. From 3 to 7 d of dietary CORT supplementation, yolk CORT and plasma uric acid concentrations and H:L ratio increased whereas plasma glucose concentration decreased. After CORT was withdrawn from the diet, the H:L ratio remained elevated. The duration of TI and plasma creatine kinase concentration did not change during and after CORT supplementation.4. Yolk CORT concentration was correlated with plasma uric acid concentration during CORT supplementation.5. The results suggest that dietary CORT supplementation could be used as a stress model and to evaluate hormone-mediated maternal effects in broiler breeder hens. © 2013 British Poultry Science Ltd.
Photoperiodic Lighting (16 Hours of Light:8 Hours of Dark) Programs During Incubation: 1. Effects on Growth and Circadian Physiological Traits of Embryos and Early Stress Response of Broiler Chickens
(Oxford Univ Press, 2012) Ozkan, S.; Yalcin, S.; Babacanoglu, E.; Kozanoglu, H.; Karadas, F.; Uysal, S.
This study was conducted to evaluate the effect of a 16L:8D photoperiod during incubation, either during the whole incubation period (Inc(0-21d)) or the last week of incubation (Inc(14-21d))1 on embryo growth, incubation performance, and light:dark rhythm of plasma melatonin and corticosterone in relation to early stress responses of newly hatched chicks to the posthatching environment. A dark incubation condition (Inc(Dark)) served as control. Three batches of eggs (n = 1,080, 1,320, 720) from Ross 308 broiler breeders were used in the experiment. Embryos from Inc(0-21d) presented a daily rhythm of melatonin at internal pipping and hatching, but Inc(Dark) embryos did not. The Inc(14-21d) group had rhythmic plasma melatonin at hatching only. A L:D rhythm of corticosterone was apparent at hatching. A significant incubation x sampling time interaction suggested that a lower increment in blood corticosterone level in Inc(0-21d) at 8 h posthatching (light period), as compared with hatching (dark period) values, might be associated with probable changes in the hypothalamic-pituitary-adrenal axis in Inc(0-21d) through incubation lighting. This finding may also suggest improved adaptation to the posthatching environment. Incubation lighting did not consistently affect brain malondialdehyde concentration; the only difference between groups was higher concentrations at hatching in Inc(14-21d), whereas incubation groups at the internal pipping stage had similar values. Mean relative asymmetry (RA) did not differ with incubation lighting. The malondialdehyde and RA results indicate that neither lighting nor darkness during the overall incubation exacerbated embryo oxidative and developmental stress. An increased breast muscle weight was observed at hatching only in Inc(14-21d). The Inc(0-21d) group had increased embryo weights relative to egg weight and decreased residual yolk but had no effect on chick weight, relative heart and liver (% of embryo weight), hatch-ability, embryo mortality, incubation time, oxidative stress, or mean RA. In conclusion, these results provide further evidence that photoperiodic lighting during incubation (Inc(0-21d)) may improve adaptation of chicks to a novel environment at hatching, possibly giving birds a better start for early posthatching development.
Photoperiodic Lighting (16 Hours of Light:8 Hours of Dark) Programs During Incubation: 2. Effects on Early Posthatching Growth, Blood Physiology, and Production Performance in Broiler Chickens in Relation To Posthatching Lighting Programs
(Oxford Univ Press, 2012) Ozkan, S.; Yalcin, S.; Babacanoglu, E.; Uysal, S.; Karadas, F.; Kozanoglu, H.
Photoperiodic incubation lighting might improve bird adaptation to a novel environment at hatching for a better start in early posthatching development. We evaluated the effect of 16L:8D lighting for either the whole incubation period (Inc(0-21d)) or the last week of incubation (Inc(14-21d) on early posthatching growth, blood melatonin, and corticosterone at 6 d as well as malondialdehyde levels in brain tissue, relative asymmetry, and overall broiler performance as an interaction with the posthatching lighting programs. Dark incubation conditions (Inc(Dark)) served as control. There were 3 incubation batches in the experiment. Chicks from 2 of 3 batches were reared either at 16L:8D or under continuous lighting (24 h) through 6 d posthatching. Batch 3 chicks were reared to 35 d under either 16L:8D or 23L:1D. The main finding was a significant incubation x posthatching lighting interaction for 35-d BW in broilers. Although groups had similar BW under continuous lighting, Inc(0-21d) and Inc(14-21d) broilers were respectively 94 and 78 g heavier than Inc(Dark) birds under 16L:8D at 35 d. Lighted incubation groups increased 0 to 6 d of gain and had higher d-6 breast muscle weights with no effect on other traits measured. Posthatching 16L:8D reduced the gain and d-6 breast muscle. Significant incubation x posthatching lighting and posthatching lighting x sampling time interactions for blood melatonin may indicate that Inc(0-21d) affects melatonin diurnal rhythms even at 6 d under continuous light. Lower blood corticosterone levels on d 6 in Inc(0-21d) chicks reared under 16L:8D posthatching may support our hypothesis that incubation lighting can modify the bird stress response, probably affecting the hypothalamic-pituitary-adrenal axis during ontogeny, and may improve adaptation to a similar environment posthatching. The lower malondialdehyde concentration in brain tissue of Inc(0-21d) birds on d 6 may indicate lower lipid peroxidation and thus lower oxidative stress compared with Inc(Dark). These results provide further evidence that Inc(0-21d) may improve both bird adaptation to a similar photoperiodic environment and growth, probably through early entrainment of circadian physiology.