Selenium Supplementation And Mega-Sel`s Place

After our series on tying-up (April, May 1998), readers asked how Mega-Sel fits into the selenium supplement picture. Mega-Sel is a liquid vitamin E and selenium supplement proported to offer predictable absorption of selenium as compared to powdered supplements or fortified feeds. The advertisements that caught our readers’ eyes claim “unparalleled absorption,” “more effective than powder or crumble selenium products” and “guaranteed to reduce muscle soreness and alleviate tying-up.”

A company-sponsored field test placed 23 horses on Mega-Sel supplementation for 30 days. All the horses had been receiving selenium-fortified grains. Four had been on powdered selenium supplements. Plasma selenium levels at the start of the trial averaged 140 ng/ml (nanogram/milliliter); by day 15 they had increased to 160 and at day 30 were an average of 190 ng/ml, confirming increased selenium levels in the blood. But is this enough to make those advertising claims’

The starting level for this study is within what is normal. This would correspond to a dietary intake of about 0.1 to 0.2 ppm selenium (at .2 mg/kg of diet, total daily intake for an average 1,100-pound horse in work of 2 mg/day), according to a study by Shellow that followed plasma selenium levels in horses at different levels of dietary supplementation with selenium selenite — the same mineral form used in Spectra’s Mega-Sel.

Horses receiving a hay-and-grain diet containing .3 to .5 ppm in the fortified grain mix would be expected to consume a total daily level of about 0.1 to 0.2 ppm. In other words, the test horses had a blood level at the start of the study that was what would have been predicted based on available absorption studies.

The most interesting finding in the Mega-Sel study, however, is with the horses that had been receiving a powdered supplement prior to Mega-Sel. Although their diet before the study had been much higher in total selenium, their blood levels were only minimally elevated above the baseline 140 ng/ml. When switched to Mega-Sel from the powder, the selenium levels after 30 days had risen significantly.

Mega-Sel is a red liquid in a highly palatable form (multiple fruit juices are used) that adheres well to grain. Plus, it tastes and smells great. It is also advisable to feed your supplemental vitamin E and selenium separate from other mineral supplements, especially minerals in an inorganic/salt form as these minerals may react with and inactivate the vitamin E and selenium.

We asked the manufacturer why Mega-Sel was potentially absorbed better than powdered sodium selenite. They told us they could not give details without revealing how they make the formula work. We asked if Mega-Sel’s absorption was superior to organic (chelated) forms of selenium, since organic/chelated selenium is absorbed better than the inorganic salts in nonruminants. Their reply was that they were unaware selenomethionine was “approved” for horses (it can be found in many of the better supplements on the market) and that if it were approved they would consider using it, if it was cost-effective. They didn’t comment directly on whether absorption could equal/exceed that of a selenomethionine-containing supplement.

Mega-Sel is billed as the “sore muscle solution” and is guaranteed to reduce muscle soreness and alleviate tying-up. Researchers have been trying to pin down the connection between selenium/vitamin E and muscle problems for years without success. We caution you that how well your muscle-sore horse responds will depend on the exact cause of the problem. Horses with severe and recurrent tying-up problems need a complete medical work-up to attempt to determine the cause. However, field experience indicates vitamin E/selenium supplementation is reasonable in any therapeutic program/treatment for muscle damage.

Bottom Line
The absorption studies using Mega-Sel do indicate it may be more effective than powders in achieving higher blood levels of selenium. If your powder or crumble/pellet is not having the expected effect on muscle function, switching to Mega-Sel may get the job done. However, we question whether or not Mega-Sel would be more effective than supplements containing selenomethionine. Mega-Sel’s price ($14.95/half gallon) also compares favorably to that of the powdered E and selenium supplements. (Selenium Toxicity: Too much selenium can produce symptoms of toxicity, including breaking off, rings on hoof walls, sloughing of hoof walls.)

Also With This Article
Click here to view ”Selenium And The Pregnant Mare.”
Click here to view ”But Should You Replace Your Powder’”

Contact Your Local Tack Store Or:

Spectra Animal Health
PO Box 70877
Marietta, GA 30007

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