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  • Author: Ulku Gulcihan Simsek x
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Open access

Yasin Baykalir and Ulku Gulcihan Simsek

Abstract

This study was conducted to investigate the performance of laying hens and to determine possible age-related changes on external and internal quality traits of their eggs and synthesis of heat shock protein 70 kDa (HSP70) in the conventional cage and organic rearing systems. For this purpose, 4 different Bovans White hybrid flocks of the same age were monitored in each of these two systems for 52 weeks. While a total of 360 eggs were examined to determine the effects of rearing system and age (30 and 60 weeks) on egg quality traits, 48 liver tissue samples were examined for the analysis of HSP70. Egg production (hen-day) and dirty egg ratio were higher in the organic rearing system (P<0.05). The age at 50% yield, the age at peak of lay, and peak production rate were calculated as 156, 218.75 days and 95.98% in the conventional system, and 155.75, 201.50 days, and 96.56% in the organic system, respectively (P>0.05). While egg weight, albumen weight, yolk weight, shell weight, shape index, and yolk colour were higher in the organic system, the crude ash ratio of eggshell and shell ratio were higher in the conventional system (P<0.05). It was also found that the egg weight, albumen weight, yolk weight, shell weight, and the percentage of yolk were higher at 60 weeks of age (P<0.001). The percentage of shell and albumen, shape index, and yolk colour were higher at 30 weeks of age (P<0.001). The interactions between rearing system and age were statistically significant in terms of shell thickness, shape index, crude ash ratio, and yolk colour (P<0.001). Stress protein (HSP70) level was affected only by the rearing system and was higher in the organic system (P<0.001). As a result, the organic system can be considered as advantageous in terms of egg production and quality traits and the eggs of young hens exhibited better properties. The high level of HSP70 in the organic system could indicate that hens were affected by the environmental conditions at higher rates and/or the hens reared in the organic system had a stronger antioxidant defence system.

Open access

Ulku Gulcihan Simsek and Nejla Ozhan

Abstract

This research was conducted to compare performance, some blood parameters, bone quality and musculus pectoralis pH level in broiler flocks containing 15,000 (I), 25,000 (II) and 35,000 (III) birds. For this purpose, two different flocks from each capacity were simultaneously observed throughout two growth periods in summer and autumn seasons. A total of 20 broilers (10 males and 10 females) per different flock capacity, having stable live weight were selected on 32nd day of growing period. Broiler chickens were slaughtered by decapitation and their blood samples were drained into special tubes. Musculus pectoralis pH measurement was performed ten minutes after slaughter. Bones were extracted from meat and analyzed. Live weights of groups on days 1, 7, 14, 21, 28 and on the day of slaughter were similar to each other (P>0.05). The mortality rate was lower in group I (P≤0.01). Feed efficiency deteriorated negligibly in group III (P=0.078). Serum glucose and uric acid levels were high in group III (P≤0.01). Intergroup differences in serum total cholesterol, very-low-density lipoprotein cholesterol (VLDL), triglycerides, protein levels and enzyme activities of alkaline phosphatase and creatine kinase were statistically insignificant (P>0.05). Dimensions, weights and ash level of tibia and femur, bone mineral density (BMD) and bone mineral content (BMC) of tibia were observed to have similar values among the groups (P>0.05). Musculus

pectoralis pH level in groups I, II and III was determined as 5.93, 5.94 and 6.13, respectively (P≤0.05).