 หัวเรื่อง:การศึกษาเปรียบเทียบลักษณะการให้ไข่ และส่วนประกอบฟองไข่ของไก่พื้นเมืองและไก่ไข่ลูกผสมทางการค้า ผู้เขียน: Ratana Chotesangasa, Supaporn Isriyodom, Nitat Gongruttananun สื่อสิ่งพิมพ์:pdf AbstractRaised in individual cages under the same farm condition with free access to feed and water and under the 15L:9D lighting programme from 18 weeks of age onwards, the reproductive performance and egg component of the native and commercial laying hens were compared. At the onset of lay, the native hen had an average age of 152.8 d, 1.51 kg body weight and weight of first egg 28.9 g compared with the commercial laying hen which had an average age of 129.3 d, 1.42 kg body weight and weight of first egg 33.4 g. Hen-day egg production of the native hen was, at all time, lower than that of the commercial laying hen; with their peak production of 38.0 and 75.5%, respectively (P<0.05). Cumulative egg production of 91.6 eggs/hen/year of the native was much lower than that of 242.9 eggs/hen/year of the commercial (P<0.05). Average feed consumption values during laying period (20-72 weeks of age) of the native and commercial laying hens were about 81 and 100 g/hen/day, respectively (P<0.05). Feed conversion ratio, during the same period, of the native ranged from 5.3-176.8 whereas those of the commercial ranged from 2.4-3.7 (P<0.05). Average egg weight of the native was always lower than that of the commercial (P<0.05). Results obtained from the egg component study of the two breeds showed that yolk, albumen and shell weights of the native hen were 14.21, 25.45 and 4.52 g/egg and of the commercial hen were 14.64, 37.24 and 5.42 g/egg, respectively (P<0.05). The evidence that the albumen and shell portions of the native were much lower than those of the commercial whereas the yolk portion was not much different, suggested that the lower egg weight of the native was mainly contributed to its lower oviduct function. |
หัวเรื่อง:ระดับสเตอรอยด์ฮอร์โมนพื้นฐาน และการพัฒนาการของอวัยวะสืบพันธุ์ของไก่พื้นเมืองและไก่ไข่ลูกผสมทางการค้าในสภาวะการให้ผลผลิตไข่ที่แตกต่างกัน ผู้เขียน:Ratana Chotesangasa, Supaporn Isriyodom,  ดร.นิรัตน์ กองรัตนานันท์, รองศาสตราจารย์ สื่อสิ่งพิมพ์:pdf AbstractBasal steroid hormone profiled in plasma of the chicken changed according to states of egg production and degrees of oviduct development. Whereas the levels of basal progesterone and estradiol showed a clear connection with the he-day egg production, the levels of testosterone and progesterone were more likely involved with the degree of oviduct development. The hen with its hen-day egg production record above 80% (Good layer) had higher (P<0.05) concentration of progesterone and estradiol than the hen with its egg production record below 25% (Layer) and the hen which laid no egg at all (Nonlayer). When a comparison was made between the 2 breeds within the same group of Good layer, it was found that the native Good layer had lower testosterone and progesterone concentrations as well as lower oviduct weight than the commercial Good layer (P<0.05). The coincidence indicated a probable involvement of the two hormones in growth and development of the oviduct. States of development of the ovary and oviduct were also related to states of egg production. It was clear that the Good layer always had heavier and longer oviduct than the Layer and the Nonlayer (P<0.05). Despite holding the same good egg production record, the native Good layer tended to have lower degree of the oviduct development than the commercial Good layer, but only the oviduct weight that the significant difference (P<0.05) was observed. The numbers of small-sized follicles (diameter < 2 mm.) of the hens in different states of egg production or of different breeds were comparable (P>0.05). The numbers of medium-size (diameter 2-8 mm.) and large-size (diameter > 8 mm.) follicles tended to increase with the hen-day egg production. The native hen also showed a trend of having fewer number of the medium-sized and large-sized follicles. The differences were, however, not significant (P>0.05). |