Supplementing Hen Diets with Vitamins A and E

[j.]

Supplementing Hen Diets with Vitamins A and E Affects Egg Yolk Retinol and α-Tocopherol Levels

Laying hens were fed a basal diet supplemented with increasing levels of retinyl acetate and α-tocopheryl acetate to investigate the effects of vitamin A and E supplementation upon egg yolk retinol and tocopherol concentrations. The high concentration of added vitamin E caused a decline in egg production and poor feed conversion. Egg quality was not affected by vitamin A and E levels. Yolk retinol concentration was enhanced by added vitamin A, from 24.6 IU/g for eggs from the control group, to 33.6 and 37.7 IU/g of yolk when hens were fed 15,000 and 30,000 IU/kg of diet. Yolk α-tocopherol was significantly increased by dietary tocopherol supplementation, ranging from 10.9 μg/g (control group) to 160.6, 264.1, and 383.2 μg/g of yolk, respectively, when 200, 400 and 600 mg/kg of ration were added, respectively. Yolk α-tocopherol was increased by 24.9 and 44.0% with increasing vitamin A supplementation at 15,000 and 30,000 IU/kg of diet, respectively. When correlation coefficients and regression equations were calculated, it was found that yolk α-tocopherol decreased (P < 0.05) as supplemental vitamin A increased, indicating the adverse effect of dietary vitamin A on yolk tocopherol deposition. The nutritional value of eggs, related to retinol and tocopherol, can be improved by dietary manipulation of hens diet, but attention must be focused on their inter-relationship.

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Effect of Dietary Vitamin A on Egg Yolk Retinol and Tocopherol Levels

Vitamin A deficiency is a serious public health problem in developing countries, and it causes death or blindness among children in these countries. Fortification of food, such as eggs, could be an important source of vitamins to control deficiency. To evaluate the effect of dietary levels of vitamin A upon reproductive performance, egg quality, and egg yolk retinol and tocopherol concentrations, laying hens were fed a basal diet (commercial ration) supplemented with increased retinyl acetate. It was observed that hen performance was not significantly affected by addition of vitamin A. Progressive increase in the incorporation of retinol into egg yolk was verified when vitamin A was supplemented to the basal diet; the percentage of increment reached 50.6% with 25,000 IU of dietary retinyl acetate/kg. Egg yolk retinol content increased linearly as dietary vitamin A increased. However, significant decreases in the egg yolk tocopherol concentrations showed an adverse effect of vitamin A supplementation. The nutritional value of eggs, related to vitamin A, can be improved by dietary manipulation of hen diets.

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[charlie]

I got chickens and am wondering if I should start supplementing.

 

[SQu]

I wonder what countries they meant? For some reason in more tropical countries in Africa like Tanzania egg yolks get pale, almost colourless . It's a bit off putting.I've always wondered why and if it was vit a shortage. They may or may not get added food at all beyond what they pick up for themselves but that should be pretty good I'd think. (Insects, frogs, lizards if mine are anything to go by! )

 

[charlie]

I have seen my girls fighting over a snake before.

 

[SQu]

!! You know those new ' the world is running out of food and we all must learn to be responsible citizens and eat insects' articles you sometimes see in the news ( are they softening us up to accept weird insect parts in our food i wonder??) well I always think that if we eat real free range eggs we're eating insects already, just recycled through a chicken. So much nicer!

 

[charlie]

lol Recycled insects, yum!!!!

 

[SQu]

Yes, it's a lovely thought, isn't it!