title: Responses of organic housed laying hens to dietary methionine and energy during a summer and winter season.
abstract: 1. The main dietary challenge in organic laying hen production is to fulfil the digestible methionine (MET) requirement in a diet consisting of ingredients of organic origin only. 2. The aim of the present experiment was to determine the response of organic housed laying hens (26-34 weeks of age) to dietary energy and MET during a summer and winter trial. Per trial, a total of 128 17-week-old Brown Nick hens were allotted to 16 pens, which were connected to an outdoor run. Each experiment comprised 8 dietary treatments according to a 4 × 2 factorial design. The factors were AFD MET level (2.3, 2.7, 3.1 and 3.5 g/kg) and energy content (10.9 and 12.1 MJ). 3. Dietary energy content did not affect energy intake (1361 kJ/d) in summer, whereas energy intake in winter was increased in hens that were fed on the 12.1-MJ diets (1514 vs. 1421 kJ/d). Maximal egg mass in summer was achieved if a diet with 3.5 g/kg MET was given, corresponding to a digestible MET intake of 421 mg/d. During winter, maximal egg mass was achieved with a digestible MET intake of 360 mg/d, which was already realised with a MET content of 2.7 g/kg. 4. Because digestible MET content for maximal egg performance differed between the summer and winter trial, dietary energy to MET ratio might be adjusted to seasonal conditions.
authors.affiliation: a Department of Animal Nutrition , Wageningen UR Livestock Research , Lelystad , The Netherlands.
authors.forename: M M
authors.initials: MM
authors.lastname: Van Krimpen
authors.forename: G P
authors.initials: GP
authors.lastname: Binnendijk
authors.forename: M A
authors.initials: MA
authors.lastname: Ogun
authors.forename: R P
authors.initials: RP
authors.lastname: Kwakkel
mesh_terms: D000821:Animal Feed / Q000032:analysis; D000822:Animal Husbandry; D000824:Animal Nutritional Physiological Phenomena; D000818:Animals; D002645:Chickens / Q000378:metabolism*; D004032:Diet / Q000662:veterinary*; D004305:Dose-Response Relationship, Drug; D002149:Energy Intake; D005260:Female; D006799:Housing, Animal; D008715:Methionine / Q000378:metabolism*; D011897:Random Allocation; D012621:Seasons
chemical_list: D008715:Methionine