IMPROVED MILBOND-TX® “VANADIUM: A FACTOR RESPONSIBLE FOR DEPIGMENTATION OF BROWN SHELLED EGGS”
EXPECTED EFFECTS OF VANADIUM IN LAYER DIETS
The adverse effects of vanadium (V) in laying hen diets have been reported by numerous investigators in several scientific journals over the past 50 years. Dietary concentrations of V used in previous experiments have ranged from 0 to 250 mg V/kg, with the majority of the investigators reporting the effects of 100 mg V/kg or less. Feeding laying hens a diet containing 30 mg V/kg or higher usually results in a decrease in feed intake, egg production, body weight, egg weight, fertility, hatchability and also poor feed conversion and increased excreta moisture. Bone, kidney, liver, and oviduct (magnum) are primary sites of V accumulation in laying hens.
Previously, the most common detrimental effect of dietary V in layers has been documented to be the decrease in interior egg quality as a result of low albumen height. A decline in albumen quality usually occurs within 48 hours after hens consume a diet containing 5 mg V/kg or greater and the decline in quality is thought to be mediated by muscle atrophy leading to an inhibition of motility in the magnum, which is the albumen-secreting portion of the hen’s oviduct. Numerous researchers have reported that supplementing a diet containing 20 mg V/kg or less with 100 mg vitamin C/kg will, in most cases, overcome the negative effect that V has on albumen quality and completely restore albumen height. The time required to restore albumen height after removing V from a hen’s diet is related to the concentration of V and the length of time the diet has been fed to the hens. When diets containing less than 15 mg V/kg are fed to laying hens, restoration of albumen quality usually occurs within 3 or 4 days. However, when higher than 30 mg V/kg diet are fed it may take up to 30 days for egg interior quality to be completely restored.
THE DEPIGMENTING EFFECT OF VANADIUM ON BROWN SHELLED EGGS
There are several factors known to cause a decline in the pigmentation of brown egg shells. Stress level of the flock, age of the laying hen, disease (especially infectious bronchitis), and chemotherapeutic agents such as sulfonamides have been reported to decrease brown egg shell pigmentation. The first report in the scientific literature documenting the depigmenting or “bleaching” effect of brown eggshells caused by V was from the laboratory of Dr. Richard Miles at the University of Florida Gainesville, Florida (USA) (Sutley et.al. 2001).
In their first study, these researchers used replicate floor pens of broiler breeders and supplemented their diet with 0, 50 or 100 mg V/kg as the compound “ammonium meta-vanadate” for a period of only seven days. A computer assisted color vision system (above photograph) was used to determine pigmentation in each egg. Within five days of feeding V there was a statistically significant (P < 0.05) decrease in the amount of brown pigmentation in the egg shells. Having previously established the negative effect on egg shell color using broiler breeders, the researchers then designed two similar experiments using Hy-Line Brown commercial egg-type layers (Odabasi et al. 2006). These hens were fed a corn-soybean meal basal diet adequate in all nutrients and energy and again supplemented with 0, 50, or 100 mg V/kg as the compound “ammonium meta-vanadate” in order to determine if V would also have a negative effect on egg shell pigmentation similar to that observed in the broiler breeders. In their second study using Hy-Line Brown hens, the researchers used a similar basal diet containing lower dietary levels of V (0, 15 or 30 mg V/kg).
In both of the above experiments with commercial egg-type brown layers there was a significant negative “bleaching” effect (P < 0.05) observed in egg shell pigmentation within three days of feeding hens the diets containing 30 mg V/kg or higher. Eggs from hens fed 15 mg V/kg diet also showed a bleaching effect, but not as great as for the higher V concentrations.
Even though eggshell pigmentation of the broiler breeder egg is not of any economic importance to the poultry industry, this is not true for the brown table-egg industry where shell color intensity and uniformity of color among eggs influence consumer preference. For example, in the Japanese egg market there are rigid standards for a uniform dark shell color, whereas other markets around the world prize a uniform light brown tint to the egg shell. Uniformity of shell pigmentation and color intensity among brown eggs are very important. Whenever pigmentation problems occur in flocks of brown egg-type hens another factor has been added to the list that might be responsible for the loss in pigmentation and that factor is V. Most of the feed ingredients used in poultry feed formulation contain very low concentrations of V. It is therefore, unlikely that V will be the factor responsible for causing a problem of pigmentation of brown-shelled eggs unless the diet contains a feedphosphate source that has a high concentration of V. The data collected in research studies at the University of Florida have shown that V is another factor which should be added to the list of factors that are responsible for depigmentation of brown-shelled eggs. In the next issue of Milwhite’s Journal the topic will focus on how egg shell pigmentation can be completely restored even though V is in the diet of brown egg-type layers.
The information presented in this issue of Milwhite’s Journal was compiled by Dr. Orlando Osuna, Director of Health Science at Milwhite, Inc. and Dr. Richard Miles, Professor Emeritus, University of Florida.
Sutley, J.P., R.D. Miles, C.W. Comer and M.O. Balaban. 2001. The influence of vanadium on pigmentation of brown-shelled eggs. Poultry Sci. 80:1039
Odabasi, A.Z., R.D. Miles, M.O. Balaban, K.M., Portier, and V. Sampath. 2006. Vitamin C overcomes the detrimental effect of vanadium on brown eggshell pigmentation. J. Appl. Poult. Res. 15:425-432.