Supplementation with humic substances in laying hens during molt

摘要

Humic substances (HS) have been used in the last two decades as a supplement in animal feed to improve performance and physiological processes that are reflected in the quality of products. 120 Hy Line Brown hens were supplemented with HS during the first 60 days of the molting stage. The experimental design was completely randomized. The birds were divided into four groups, each with 30 hens. The first and second groups were supplemented with 0.1 and 0.2% HS, respectively. The third group was supplemented with 0.25 mg/kg levamisole hydrochloride. The fourth group received no supplementation. The effect of humic substances on production parameters and egg quality (laying percentage, daily mortality, feed conversion ratio, shell thickness, albumen thickness, and yolk color) was evaluated. Mortality was not related to the experiment. HS supplementation resulted in no significant differences on hen weight, laying percentage, egg weight, or feed conversion ratio (p 0.05). However, HS supplementation improved egg quality in terms of increased shell thickness and albumin at days 30 and 60 post-molt.