Biotin studies in pigs. 3. Biotin absorption and synthesis

Area of Science:

• Animal Nutrition
• Gastroenterology
• Microbiology

Background:

• Biotin is an essential vitamin crucial for various metabolic processes.
• Understanding biotin absorption and synthesis in pigs is vital for optimizing animal health and productivity.
• The role of hind-gut microbial synthesis in meeting biotin requirements requires further investigation.

Purpose of the Study:

• To investigate the impact of dietary biotin supplementation on biotin absorption and hind-gut synthesis in growing pigs.
• To quantify biotin flow through the gastrointestinal tract of pigs fed diets with varying biotin levels.
• To assess the contribution of microbial biotin synthesis in the large intestine.

Main Methods:

• Eight pigs were fed semi-purified diets with either 10 µg/kg (unsupplemented) or 80 µg/kg (supplemented) biotin from 5 to 94 days of age.
• Biotin levels were measured in digesta at different sections of the gastrointestinal tract (stomach, small intestine, caecum, large intestine, colon).
• Intake and flow rates of biotin were calculated to determine absorption and synthesis.

Main Results:

• Biotin intake and stomach outflow were significantly higher in supplemented pigs (112 µg/d) compared to unsupplemented pigs (13.5 µg/d).
• Biotin flow decreased significantly along the small intestine in supplemented pigs, from 39 µg/d to 7.9 µg/d.
• Biotin levels in the caecum, large intestine, and colon were similar between groups (17-54 µg/d), suggesting microbial synthesis.

Conclusions:

• Dietary biotin supplementation increases biotin intake and absorption in the upper gastrointestinal tract of pigs.
• Significant biotin synthesis occurs in the hind-gut of pigs, contributing to overall biotin availability.
• The gut microbiota plays a crucial role in biotin production, potentially influencing the requirement for dietary supplementation.