title: Long-term effects of choline on productive performance and egg quality of brown-egg laying hens.
abstract: A total of five hundred forty 19-wk-old HyLine Brown hens were used to study the long-term effects of increasing choline with 0 (control), 425, 850, 1,700, 3,400, and 6,800 mg/kg of corn-soybean meal-based diets on productive performance and egg quality. Phase 1 was from 19 to 58 wk, and phase 2 was from 59 to 68 wk. During the whole experimental period, dietary choline had no significant effects on feed intake, egg weight, and egg mass (P > 0.05). During phase 1, egg production decreased linearly (P < 0.05) and feed conversion ratio (FCR) tended to increase linearly (P = 0.057) with increasing choline level in the diet. Moreover, BW decreased both linearly (P < 0.01) and quadratically (P < 0.05) as choline increased from 0 to 6,800 mg/kg. No significant treatment effects were found for shell thickness and shell strength of eggs (P > 0.05). However, albumen height and Haugh units increased linearly (P < 0.01 and P < 0.05, respectively) as choline increased during phase 2. Compared with the control group, diets supplemented with 425 or 850 mg of choline/kg significantly (P < 0.01) improved yolk color during phase 1. This study indicates that a dietary choline level of no more than 700 mg/kg is sufficient to maintain egg production. The effect of choline on egg quality was minimal when hens were fed a corn-soybean meal-based diet from 19 to 68 wk of age.
authors.affiliation: Institute of Animal Science, Chinese Academy of Agricultural Sciences, Beijing, People's Republic of China.
authors.forename: Q H
authors.initials: QH
authors.lastname: Zhai
authors.forename: X F
authors.initials: XF
authors.lastname: Dong
authors.forename: J M
authors.initials: JM
authors.lastname: Tong
authors.forename: Y M
authors.initials: YM
authors.lastname: Guo
authors.forename: Y E
authors.initials: YE
authors.lastname: Bao
mesh_terms: D000821:Animal Feed / Q000032:analysis; D000824:Animal Nutritional Physiological Phenomena; D000818:Animals; D002645:Chickens; D002794:Choline / Q000008:administration & dosage / Q000494:pharmacology*; D004032:Diet / Q000662:veterinary; D004334:Drug Administration Schedule; D004531:Eggs / Q000592:standards*; D005260:Female; D010860:Pigments, Biological
chemical_list: D010860:Pigments, Biological; D002794:Choline