Selenium absorption by canine jejunum.

Area of Science:

• Nutritional Science
• Gastroenterology
• Trace Element Metabolism

Background:

• Selenium deficiency is linked to diseases in animals and potentially humans.
• Understanding selenium absorption is crucial for human and animal health.
• Dietary selenium exists in various chemical forms, influencing its bioavailability.

Purpose of the Study:

• To compare the in vivo jejunal absorption rates of different selenium compounds in dogs.
• To investigate the absorption mechanism of selenium from D,L-selenomethionine.
• To determine if amino acid-bound selenium is absorbed differently than inorganic selenium.

Main Methods:

• Triple-lumen perfusion technique in healthy dogs to measure selenium absorption from the jejunum.
• Administration of trace amounts of D,L-selenomethionine, D,L-selenocystine, and sodium selenite.
• Intestinal perfusion with L-[75Se]selenomethionine to track absorption and incorporation in anesthetized dogs.

Main Results:

• Selenium absorption rates varied significantly: D,L-selenomethionine (1.97±0.04%/cm) > D,L-selenocystine (1.15±0.06%/cm) > sodium selenite (0.51±0.07%/cm).
• Studies with L-[75Se]selenomethionine showed quantitative correspondence between luminal disappearance and portal venous appearance (74±6%) and tissue incorporation (24±5%).
• These findings support active transport for amino acid-bound selenium and potentially diffusion for sodium selenite.

Conclusions:

• Amino acid-bound selenium compounds (selenomethionine, selenocystine) are absorbed more efficiently from the canine jejunum than sodium selenite.
• Active transport mechanisms in the gut mucosa likely facilitate the enhanced absorption of amino acid-bound selenium.
• Sodium selenite absorption may occur via passive diffusion, resulting in a slower uptake rate.