Nutritional levels of digestible threonine in brown-egg laying hens from 75 to 90 weeks of age

Abstract

An experiment was conducted in the Department of Experimental Stations of the Universidade Tecnológica Federal do Parana -UTFPR campus Dois Vizinhos -PR, with the objective of determining the nutritional levels of threonine for laying hens aged 75 to 90 weeks. One hundred fifty laying Shaver Brown pullets were used in a completely randomized design (CRD) submitted to a basal diet containing 2.85 kcal ME/g and 148.7 g/kg CP, supplemented with 4.6; 4.9; 5.2; 5.5 or 5.8 g/kg of digestible Lthreonine (98 %), which provided 0.000, 0.027, 0.058, 0.089 or 0.120% threonine, respectively. The feed conversion, egg production, egg weight, egg mass and internal egg quality were not affected (P> 0.05) by the threonine in the diet. The Haugh unit showed a linear effect with threonine consumption in that it increased levels of digestible amino acids in the diet. The variables percent albumin and shell showed quadratic effects, so the recommended dietary digestible threonine level was 5.20 g/kg, which corresponds to 0.648 g threonine/hen/day, and 5.25 g/kg, which is equivalent to 0.654 g threonine/hen/ day, respectively. The specific gravity was affected by the level of threonine; the indicated level is 5.22 g/kg, equivalent to 0.651 g of threonine/hen/day obtained by the quadratic effect. Key words: Digestible amino acid, egg quality, performance ResumoConduziu-se um experimento no Núcleo de Unidades de Ensino e Pesquisa da Universidade Tecnológica Federal do Paraná -UTFPR, Campus de Dois Vizinhos -PR, com o objetivo de determinar os níveis nutricionais de treonina digestível para poedeiras comerciais, no período de 75 a 90 semanas de idade. Foram utilizadas 150 poedeiras Shaver Brown semipesadas num delineamento inteiramente casualizado (DIC), submetidas à uma ração basal contendo 2,85 Kcal EM/g, 148,7g/kg de PB, suplementada com 4,6; 4,9; 5,2; 5,5 e 5,8g/kg de L-treonina digestível (98%), que forneceu 0,000; 0,027; 0,058; 0,089 e 0,120% de treonina digestível, respectivamente. A conversão alimentar, a produção de ovos, o peso do ovo, massa de ovos e a qualidade interna dos ovos não foram influenciados (P>0,05) pelos níveis de treonina na dieta. A unidade Haugh e o consumo de treonina apresentaram efeito linear à medida em que aumentavam os níveis do aminoácido digestível na dieta. As variáveis porcentagem de albúmen e casca apresentaram efeito quadrático e os níveis nutricionais de treonina digestível recomendados foram de 5,20g/kg, o que corresponde a 0,648 g de treonina/ave/dia e, 5,25g/kg que equivale a 0,654 g de treonina/ave/dia, respectivamente. A gravidade específica foi afetada pelos níveis de treonina digestível, e o nível indicado é de 5,22g/kg, que equivale a 0,651 g de treonina/ave/dia obtido por meio de efeito quadrático. Palavras-chave: Aminoácido digestível, desempenho, qualidade do ovo

Multivariate modeling strategies to predict nutritional requirements of essential amino acids in semiheavy second-cycle hens

“…The estimated level of iThr at 20 weeks of production of the SCLH was also different than that recommended by Rostagno et al (2017) of 674 mg/hen•day for laying hen brown eggs with mediumsuperior performance in the first production cycle, Agustini et al (2014) of 562 mg/hen•day for Shaver Brown hens (75-90 weeks old), Hy-Line Brown commercial layer management guide (Hy-Line, 2014) of 499 mg/hen•day, and Schmidt et al (2010) of 462 mg/hen•day for Lohmann Brown line SCLH (79-95 weeks old). These reports were lower than the iThr level recommended in this study of 717 mg/hen•day for the H&N Brown SCLH.…”

“…In our study, treatment 23 presented a good intake and adequate EAA ratios (Met+Cys/Lys = 91% and Thr/Lys = 63%). It is noteworthy that the aminoacitic balance of the diet and the experimental diet composition are factors closely related to FI in SCLH (Agustini et al, 2014).…”

“…A total of 2300 records (23 treatments × five replicates × 20 weeks) were added during the fieldwork. The EAA ranges in the experimental design were established to include the levels for second-cycle hens in commercial genetic lines available in the literature (Schmidt et al, 2009a(Schmidt et al, , 2009b(Schmidt et al, , 2010Schneider, 2011;Polese et al, 2012;Agustini et al, 2014;Hy-Line, 2014) and levels recommended by Rostagno et al (2011) and Rostagno et al (2017) for laying-hen brown eggs with medium-superior performance in the first production cycle.…”