Absorption, excretion and tissue distribution of stable zinc and 65zinc in ponies.

The research article is about the study of the absorption, excretion, and distribution of zinc in ponies with different amounts of dietary zinc intake.

Overview of the Research

• The research conducted three different experiments to study the effect of various dietary inputs of zinc in the form of stable Zn and radioactive 65Zn in ponies. These experiments include the intravenous administration of 65Zn and analyzing the metabolism of both types of zinc.
• The research mainly focused on analyzing the amount of zinc absorbed and retained, the primary route of excretion, and the distribution in the tissues, including organs and bones.

First Experiment

• Three ponies were analyzed in three different phases. They were fed a corn and beet pulp diet, adding two amounts of supplemental Zn, and the natural diet alone.
• The ponies absorbed and retained more zinc when fed 250 mg of supplemental Zn compared to the basal diet alone or the basal diet plus 520 mg of supplemental Zn. This indicates that a certain amount of additional intake can enhance the absorption, but excessive intake does not necessarily augment the effect.
• The major route of excretion for stable Zn and 65Zn was observed to be the intestinal tract.

Second Experiment

• Three ponies were fed a diet of beet pulp, corn starch, and alfalfa meal. The diet was adopted with varying amounts of supplemental Zn.
• The ponies retained a more significant percentage of a 65Zn dose when fed the basal diet or the basal diet plus 240 mg of supplemental Zn than when fed 480 mg of supplemental Zn. The results were similar to the first experiment, which again showed that excessive intake did not yield higher absorption.

Third Experiment

• Four ponies on a commercial pelleted diet were given an intravenous dose of 65Zn. The ponies were then killed 7 to 14 days later and the tissues were reviewed for radioactivity.
• The organs of the ponies such as liver, pancreas, kidney, heart, and lung contained a greater percentage of 65Zn than the structural organs like bone and muscle, suggesting different levels of absorption in different body organs. The wall of the gastrointestinal tract contained more radioactivity compared to the contents, emphasizing the excretion route identified in the first experiment.