QUALITY OF COMMERCIAL EGG FROM LAYING HENS TREATED WITH DOXYCYCLINE

Abstract

Doxycycline is a drug from the tetracycline group indicated for the treatment of different diseases, mainly infectious coryza. However, antimicrobials from the tetracycline group have the ability to bind and make minerals important for egg formation unavailable. The aim of this project is evaluate interference of doxycycline in quality of commercial egg. A study had carried out with 100 Dekalb Brown® laying hens where evaluated the yolk color, Haugh unit, color eggshell, weight and thickness eggshell. The delimitation had completely randomized in a 2x2 factorial scheme, resulting in treatments: without doxycycline at day 5; with doxycycline a day 5; without doxycycline at day 10; with doxycycline at day 10. Four eggs had gathered per replicate, totaling 48 eggs analyzed per treatment in each of the analyzed periods. No significant differences were found between treatments for internal egg quality variables (yolk color and Haugh unit). For the shell quality variables, there was a significant reduction in yellow levels with the use of doxycycline for 10 days, in addition to a reduction in shell weight and apical and equatorial shell thickness, mainly on the 10th day and with the use of doxycycline. It is conclude that the use of the doxycycline does not interfere in the internal quality of the eggs, but it gives a greyish tonality to the eggshells, and reduces their weight and thickness.