Citation
Callejo Ramos, Antonio and Dos Santos, Andrea Luciana and Nicodemus Martin, Nuria and Gutiérrez del Alamo, A. and Buxade Carbo, Carlos and Borges Amorim, Alessandro and Dib Saleh, Mayra Anton
(2017).
Effect of digestible threonine level of dietar on productivo performance, commercial ego grading and ego Quality of 55 to 61 week-old playing heno.
"Journal of Veterinary Health Care", v. 1
(n. 2);
pp. 18-25.
ISSN 2575-1212.
https://doi.org/10.14302/issn.2575-1212.jvhc-17-1795.
Abstract
The aim of this study was to establish the digestible threonine (dig. Thr) requirements and the ideal
proportion between Thr and Lys for Isa Brown laying hens on productive traits and egg quality characteristics
from 55- to 58- and 59- to 61 weeks of age. Increased levels of L-Thr were added to a basal diet that
contained 3.7 g/kg of dig. Thr. Therefore, diets containing 3.7, 4.0, 4.3, 4.6, 4.9 and 5.2 g/kg of dig. Thr and
a relation between Thr and Lys of 0.58, 0.63, 0.67, 0.72, 0.77 and 0.81, respectively were provided to laying
hens. A total of 216 hens were distributed in a randomized design among the 6 experimental diets. There
were 9 replicates per treatment, and 4 birds per replicate. Data were analyzed by repeated measures analysis
using the MIXED procedure of SAS. The main effects (dig. Thr level and experimental period) and their
interaction were studied. Neither the dig. Thr level nor the experimental period had effect on performance
traits and egg quality. Also, commercial egg grading was not influenced by period. However, there was a
quadratic effect (P<0.001) of dig. Thr level within each scale egg weight. In conclusion, diets containing more
than 3.7 g/kg of dig. Thr do not improve laying hens productivity at 55- to 61-week-old.