Bioavailability of rumen bacterial selenium in mice using tissue uptake technique

Area of Science:

• Animal Nutrition
• Trace Element Metabolism
• Gastrointestinal Physiology

Background:

• Selenium (Se) is an essential trace element crucial for various physiological functions.
• Rumen bacteria can synthesize and accumulate Se, raising questions about its bioavailability.
• Understanding Se bioavailability from different sources is vital for optimizing animal nutrition and health.

Purpose of the Study:

• To evaluate the bioavailability of rumen bacterial Selenium (Se) in growing female mice.
• To compare tissue Se uptake from bacterial Se versus inorganic selenite.
• To determine the impact of dietary Se source on Se deposition in mouse tissues.

Main Methods:

• Rumen fluid was collected from a wether fed a Se-containing diet.
• Bacterial-rich precipitate was isolated, freeze-dried, and incorporated into mouse diets.
• Three dietary treatments were administered to mice: low Se (Diet 1), selenite-supplemented (Diet 2), and bacterial Se-supplemented (Diet 3).
• Tissue Se concentrations were measured after a 7-day feeding period.

Main Results:

• Mice fed the selenite-supplemented diet (Diet 2) exhibited significantly higher tissue Se concentrations (P < 0.05) compared to other groups.
• No significant differences in tissue Se concentrations were found between mice fed the low Se diet (Diet 1) and those fed the bacterial Se diet (Diet 3).
• Kidney and liver showed the highest Se accumulation across all treatments.

Conclusions:

• Dietary Selenium (Se) from rumen bacteria is poorly bioavailable for absorption in the mouse intestine.
• Selenite serves as a more readily available source of Selenium for tissue deposition in mice.
• Further research is needed to elucidate the mechanisms limiting bacterial Se absorption.