title: Effects of incubator humidity and hen age on yolk composition in broiler hatching eggs from young breeders.
abstract: The effects of broiler breeder age (26, 28, and 30 wk) and incubator relative humidity (43, 53, and 63% RH) on yolk sac weight and composition in broiler hatching eggs between 16 and 19 d of incubation were evaluated. Percentage yolk sac weight was reduced in eggs from the youngest (26 wk) breeder hens and in eggs incubated at 53% RH. Percentage yolk moisture, in eggs from the youngest hens, was lowest at 16 d and was highest at 19 d, and percentage yolk lipid was highest at 16 and 17 d of incubation in eggs from 30-wk-old hens. Percentage yolk lipid content was higher at 63% RH compared with 53% RH in eggs from 26-wk-old breeders but was lower in eggs incubated at a 43% RH compared with 53 and 63% RH from 30-wk-old breeders. Yolk stearic and arachidonic acid concentrations were higher and myristic acid concentration was lower in eggs from the 26-wk-old hens. Conversely, the highest yolk concentrations of linolenic and palmitoleic acids occurred in eggs from 30- and 28-wk-old breeders, respectively. At 16, 17, 18, and 19 d of incubation, yolk oleic acid concentrations were significantly, but variably, affected by breeder age, whereas linoleic acid concentration was highest in 26-wk-old breeders only at 19 d. Palmitic acid concentration at 17 d was lower in eggs incubated at 53% RH compared with 43 and 63% RH. Rate of yolk uptake from the yolk sac by embryos may be increased by incubating eggs at 53% RH, and the effects of changes in RH between 43 and 63% on yolk lipid content are influenced by breeder age.
authors.affiliation: Department of Poultry Science, Mississippi State University, Mississippi State 39762, USA.
authors.forename: M R
authors.initials: MR
authors.lastname: Burnham
authors.forename: E D
authors.initials: ED
authors.lastname: Peebles
authors.forename: C W
authors.initials: CW
authors.lastname: Gardner
authors.forename: J
authors.initials: J
authors.lastname: Brake
authors.forename: J J
authors.initials: JJ
authors.lastname: Bruzual
authors.forename: P D
authors.initials: PD
authors.lastname: Gerard
mesh_terms: D000367:Age Factors; D000818:Animals; D001823:Body Composition; D001947:Breeding; D002642:Chick Embryo / Q000254:growth & development* / Q000502:physiology; D002645:Chickens; D004530:Egg Yolk / Q000737:chemistry*; D006813:Humidity; D007185:Incubators / Q000662:veterinary; D008055:Lipids / Q000032:analysis*; D015017:Yolk Sac / Q000502:physiology
chemical_list: D008055:Lipids