title: Commercially available amino acid supplementation of low-protein diets for broiler chickens with different ratios of digestible glycine+serine:lysine.
abstract: This work studied the effect of supplementing commercially available amino acids in low-protein diets using different ratios of digestible (dig) glycine+serine:lysine (Gly+Ser:Lys) on performance, serum parameters, feathering, and litter characteristics of broiler chickens during the starter period. A total of one thousand fifty 1-d-old Cobb-Vantress male chicks were distributed in a completely randomized experimental design into 6 treatments with 5 replicates of 35 birds each. The treatments were as follows: T1, control diet based on corn and soybean meal formulated with 22% CP (dig Gly+Ser:Lys ratio of 147); T2, diet with a 2% CP reduction, supplemented with Val (dig Gly+Ser:Lys ratio of 137); T3, similar to T2 with the addition of Gly (dig Gly+Ser:Lys ratio of 147); T4, diet with a 3% CP reduction, supplemented with Val, Ile, and Arg (dig Gly+Ser:Lys ratio of 127); and T5 and T6, similar to T4 with the addition of Gly (dig Gly+Ser:Lys ratios of 137 and 147, respectively). At 7 and 21 d, broilers that had received diets with a 3% CP reduction (19% CP) and a Gly+Ser:Lys ratio that was equivalent to 127 had lower G:F (P < 0.05) and lower total protein and albumin serum concentrations (P < 0.05) than those broilers that received the control feed. However, these parameters were restored to the same level as the control diet with an increase in the dig Gly+Ser:Lys ratio from 127 to 137 and 147. Diets with a 3% CP reduction (19% CP) resulted in litter with reduced (P < 0.05) nitrogen content and lower ammonia emission than the litter of broilers receiving the control diet. The treatments did not influence (P > 0.05) the feather length or feathering scores at 21 or 28 d of age. The supplementation of essential amino acids while maintaining dig Gly+Ser:Lys ratios at and above 137 allowed for a reduction in the dietary CP of 3% without undermining the performance, feathering or serum parameters of early stage broilers.
authors.affiliation: Departamento de Zootecnia, Universidade Estadual de Maringá, Av. Colombo, 5790 Bloco j45, Maringá, Paraná, 87020-900, Brazil.
authors.forename: I C
authors.initials: IC
authors.lastname: Ospina-Rojas
authors.forename: A E
authors.initials: AE
authors.lastname: Murakami
authors.forename: C
authors.initials: C
authors.lastname: Eyng
authors.forename: R V
authors.initials: RV
authors.lastname: Nunes
authors.forename: C R A
authors.initials: CR
authors.lastname: Duarte
authors.forename: M D
authors.initials: MD
authors.lastname: Vargas
mesh_terms: D000821:Animal Feed / Q000032:analysis*; D000824:Animal Nutritional Physiological Phenomena; D000818:Animals; D002645:Chickens / Q000254:growth & development; D004032:Diet / Q000662:veterinary; D004044:Dietary Proteins / Q000008:administration & dosage*; D019587:Dietary Supplements; D005998:Glycine / Q000008:administration & dosage / Q000737:chemistry / Q000494:pharmacology*; D008239:Lysine / Q000008:administration & dosage / Q000737:chemistry / Q000494:pharmacology*; D008297:Male; D012694:Serine / Q000008:administration & dosage / Q000737:chemistry / Q000494:pharmacology*
chemical_list: D004044:Dietary Proteins; D012694:Serine; D008239:Lysine; D005998:Glycine