title: Estimation of the optimum digestible lysine level for Cherry Valley ducks.
abstract: The aim of the current study was to determine the digestible lysine (DLys) requirement of Cherry Valley ducks from 1 to 14 d and from 15 to 35 d of age. One-day-old male Cherry Valley ducks (n = 320) were divided randomly and evenly into five treatments with 8 replicates of 8 birds. Ducks were fed adequate levels of digestible amino acid but with graded levels of DLys: 0.80, 0.88, 0.96, 1.04, and 1.12% from 1 to 14 d; 0.60, 0.68, 0.76, 0.84, and 0.92% from 15 to 35 d. At 35 d of age, 8 ducks per treatment were slaughtered for evaluating the yields of abdominal fat, subcutaneous fat, breast meat, and leg meat. Additionally, a 7-d metabolizable experiment was conducted with ducks of the same hatch beginning on d 35 (8 ducks per treatment). The results showed that the DLys level in diet had a quadratic relationship both with the average daily gain (ADG) and feed:gain ratio (F/G). According to the quadratic model, an optimum digestible lysine level was 0.948% from 0 to 14 d and 0.758% from 15 to 35 d based on ADG. The digestible lysine level for obtaining minimum F/G were 0.986% (0 ∼ 14 d) and 0.792% (15 ∼ 35 d), respectively. Breast meat yield (P = 0.110) and subcutaneous fat percentage (P = 0.021) showed a quadratic or linear response to the increasing dietary DLys level. To achieve maximum breast meat yield, the digestible lysine level of 0.961% and 0.761% were needed for the starter period (1 ∼ 14 d) and the growth period (14 ∼ 35 d), respectively. N excretion showed a quadratic response to the increasing dietary DLys level (P = 0.103). The results of the current study suggested that the optimum digestible lysine level was very different with the response criterion. The dietary digestible lysine levels were 0.948, 0.961% in the starter period (1 ∼ 14 d) and 0.758, 0.761% in the growth period (15 ∼ 35 d) for ADG, F/G, respectively.
authors.affiliation: Department of Animal Nutrition and Feed Science, College of Animal Science and Technology, Huazhong Agricultural University, Wuhan, 430070, China.
authors.forename: Y F
authors.initials: YF
authors.lastname: Zhou
authors.affiliation: Department of Animal Nutrition and Feed Science, College of Animal Science and Technology, Huazhong Agricultural University, Wuhan, 430070, China.
authors.forename: Y Q
authors.initials: YQ
authors.lastname: Liu
authors.affiliation: Department of Animal Nutrition and Feed Science, College of Animal Science and Technology, Huazhong Agricultural University, Wuhan, 430070, China.
authors.forename: H K
authors.initials: HK
authors.lastname: Wei
authors.affiliation: Department of Animal Nutrition and Feed Science, College of Animal Science and Technology, Huazhong Agricultural University, Wuhan, 430070, China.|The Cooperative Innovation Center for Sustainable Pig Production, Wuhan, Hubei, China.
authors.forename: J
authors.initials: J
authors.lastname: Peng
mesh_terms: D000821:Animal Feed / Q000032:analysis; D000824:Animal Nutritional Physiological Phenomena / Q000502:physiology*; D000818:Animals; D004032:Diet / Q000662:veterinary*; D004063:Digestion / Q000502:physiology*; D004372:Ducks / Q000254:growth & development / Q000502:physiology*; D004734:Energy Metabolism / Q000502:physiology*; D008239:Lysine / Q000008:administration & dosage / Q000378:metabolism*; D008297:Male; D008460:Meat / Q000032:analysis; D010369:Pectoralis Muscles / Q000502:physiology; D011897:Random Allocation; D050151:Subcutaneous Fat / Q000378:metabolism; D015430:Weight Gain / Q000502:physiology*
chemical_list: D008239:Lysine
keywords: Cherry Valley ducks; breast meat; digestible lysine; growth performance; subcutaneous fat