Effect of different levels of energy and protein on performance of Khazak hens at the first period of laying

Abstract

Introduction: The diets of laying hens can vary depending on factors such as strain, production
targets, age, and climatic conditions. Due to the limitations in basic studies in estimating the
requirements of native birds, it is necessary to perform studies in this field, so that the
requirements are commensurate with the climatic conditions of the region and the production
rate. Therefore, the present study was conducted to investigate the effect of different levels of
dietary energy and protein on production performance and egg quality in early laying of Khazak
hens and to select the optimal levels of energy and protein at this stage of production.
Materials & Methods: In this study, 160 Khazak-laying hens aged 25 weeks were selected
and in a completely randomized design as a factorial experiment with two levels of
metabolizable energy (2700 and 2900 kcal ME/kg DM of diet) and two levels of crude protein
(15% and 19%) with 4 replicates and 10 birds in each replication were fed for 90 days.
Production yield and egg quality traits were measured during the experiment. Data were
analyzed using the generalized linear model procedure and the means were compared using the
Turkey’s test.
Results: Energy level had a significant effect on laying percentage, egg mass, feed intake and
feed conversion ratio, and protein level had a significant effect on feed intake and feed
conversion ratio (P˂0.05). Also, the interaction of energy and protein on all production traits
except the average weight of eggs was significant (P˂0.05), so that egg production percentage,
egg mass increase and feed consumption and feed conversion ratio decreased with increasing
energy and protein levels. Although the highest quality eggs were observed from hens that
consumed the diet with the lowest energy and protein, but it was not significant compared to
eggs produced by hens that consumed the diet with the highest energy and protein.
Conclusion: The results showed that diets containing 19% CP and 2900 kcal ME improved
production and feed conversion ratio, and the quality of produced eggs did not differ
significantly from diets containing low levels of energy and protein. Therefore, the diet with
19% CP and 2900 kcal ME is ideal for Khazak hens in the first period of laying hen.