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Low utilization of carotene by sheep
Summary
Sheep poorly absorb beta-carotene, a vital nutrient, due to digestive physiology. This study investigated carotene absorption in Awassi rams, revealing low apparent digestibility and suggesting ruminant digestion hinders nutrient uptake.
Area of Science:
- Animal Nutrition
- Digestive Physiology
- Ruminant Metabolism
Background:
- Beta-carotene is essential for animal health and productivity.
- Ruminants have unique digestive systems that may affect nutrient absorption.
- Understanding beta-carotene bioavailability is crucial for optimizing sheep diets.
Purpose of the Study:
- To determine the apparent digestibility of beta-carotene in Awassi rams.
- To investigate the influence of different carotene sources and carriers on absorption.
- To elucidate the factors affecting beta-carotene bioavailability in sheep.
Main Methods:
- Balance trials were conducted with Awassi rams fed varying beta-carotene supplements.
- Carotene was administered orally (pelleted alfalfa, water-dispersible preparation) and abomasally (aqueous dispersion, oil-based carriers).
- Fecal recovery and blood radioactivity (using 3H-labelled carotene) were measured to assess absorption and degradation.
Main Results:
- Oral beta-carotene supplements showed high fecal recovery (92-98%) with a low-carotene diet.
- Abomasal administration revealed poor recovery (<50%) when carotene was dissolved in triglycerides.
- Degradation in the lower intestinal tract, not enhanced absorption, explained low fecal recovery in oil carriers.
Conclusions:
- Awassi rams exhibit poor beta-carotene absorption, especially from oil-based carriers.
- Ruminant digestive physiology may impede efficient micellar solubilization of nonpolar lipids.
- Further research is needed to enhance beta-carotene bioavailability in sheep.
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