title: Effect of prenatal temperature conditioning of laying hen embryos: Hatching, live performance and response to heat and cold stress during laying period.
abstract: This study was designed to determine the effect of prenatal temperature conditioning on hatching and live performance of laying chickens, and response to heat and cold stress during laying period. A total of 3600 eggs obtained from ATAK-S brown parent stock were incubated at control (37.5°C, CONT-Inc), cyclic low (36.5°C/6h/d from 10 to 18d of incubation, LOW-Inc) or high (38.5°C/6h/d from 10-18d of incubation, HIGH-Inc) incubation temperatures. Hatched chicks per incubation temperature were reared under standard rearing conditions up to 26wk. From 27 to 30wk, hens from each incubation temperature were divided into 3 environmentally controlled rooms and reared at control (20±2°C, CONT-Room), low (12±2°C, COLDS) or high (32±2°C, HEATS) temperatures. Hatching performance, body weight, egg production, and plasma triiodothyronine (T3) and thyroxine (T4) levels and oxidant and antioxidant activities were evaluated. The highest hatchability was for LOW-Inc chicks while HIGH-Inc chick had similar hatchability to CONT-Inc. There was no effect of incubation temperatures on plasma MDA, GSH-Px, activities and T4 concentrations on day of hatch. LOW- Inc chicks had higher SOD activities and T3 concentrations compared to the other groups. Although chick weight was similar among incubation temperature groups, CONT-Inc chicks were heavier than those cyclic incubation temperature groups until 12wk of age. Incubation temperature had no effect on sexual maturity age and weight and egg production of laying hens. From 27 to 30wk, regardless of incubation temperature, HEATS hens lost weight from day 0 to 10, had the highest cloacal temperatures and lowest feed consumption and egg production while COLDS hens had the lowest cloacal temperatures. At day 5, T4 level was higher in LOW-Inc hens at COLDS but it was higher in HIGH-Inc hens at HEATS compared to CONT-Inc. These data may suggest a modification in thyroid activity of hens that were conditioned during the incubation period. Moreover under COLDS condition, SOD production of LOW-Inc hens was higher than those of CONT- and HIGH-Inc hens indicating an induction in antioxidant enzyme activity. Nonetheless, prenatal temperature conditioning of laying hen embryos had no advantage on laying performance of hens under temperature stress conditions.
authors.affiliation: Poultry Research Station, Ankara, Turkey.
authors.forename: S
authors.initials: S
authors.lastname: Kamanli
authors.affiliation: Ordu University, Faculty of Agriculture, Department of Animal Science, Ordu, Turkey.
authors.forename: I
authors.initials: I
authors.lastname: Durmuş
authors.affiliation: Ege University, Facultyof Agriculture, Department of Animal Science, Izmir, Turkey. Electronic address: servet.yalcin@ege.edu.tr.
authors.forename: S
authors.initials: S
authors.lastname: Yalçın
authors.affiliation: Poultry Research Station, Ankara, Turkey.
authors.forename: U
authors.initials: U
authors.lastname: Yıldırım
authors.affiliation: Ankara University, Faculty of Veterinary Medicine, Department of Biochemistry, Ankara, Turkey.
authors.forename: Ö
authors.initials: Ö
authors.lastname: Meral
mesh_terms: D000064:Acclimatization; D000818:Animals; D002642:Chick Embryo; D002645:Chickens / Q000254:growth & development*; D003080:Cold Temperature; D006358:Hot Temperature; D013312:Stress, Physiological
keywords: Antioxidant status; Incubation temperature; Laying chicks; Prenatal conditioning; Temperature adaptation