Effect of Feeding and Withdrawal of Vanadium and Vitamin C on Egg Quality and Vanadium Residual Over Time in Laying Hens

Abstract

This experiment examined the egg quality of hens fed vanadium (V) and vitamin C (VC) during storage, as well as the V and VC withdrawal on egg quality and V residual in egg. A total of 360 laying hens (31weeks old) were randomly allotted into a 3×2 factorial arrangement treatments (6 replicates and 10 chicks per replicate) with three levels of dietary V (0, 5, and 10mg/kg) and two levels of VC (0 and 100mg/kg) for 19weeks (feeding V and VC 12weeks, recovery 7weeks). The V residual in eggs at 4, 8, and 12th weeks were increased (linear effect, P≤0.01) as V levels increased and was not detected in albumen at 7th week after V withdrawal. Followed by 12-week feeding period, albumen height and Haugh unit of eggs during 2-week storage were decreased (linear and quadratic effect, P<0.01) by dietary V supplementation. Lightness value was increased (linear effect, P<0.01), whereas redness and yellowness value of the eggshell were lowered (linear effect, P<0.01) in V-containing diet. During 7-week withdrawal period, eggs from groups pre-feeding 5 and 10mg/kgV had lower (linear effect, P<0.01) overall albumen height and Haugh unit. The reducing effect on albumen height and HU continued to be observed until the seventh week, whereas the bleaching effect on eggshell color disappeared after 1-week withdrawal. The results indicated that feeding 5 or 10mg/kg V increases egg V residual and reduces egg albumen quality and bleached the shell color, and the impaired albumen quality induced by 10mg/kg of V lasted at least 6weeks after changing to no V supplementation diet. The addition of VC did not show to affect egg quality during storage or recovery phase.