The effect of feeding on CO2 production and energy expenditure in ponies measured by indirect calorimetry and the 13C-bicarbonate technique.

The research article investigates how feeding times affected carbon dioxide production and energy expenditure in ponies, measured through two different techniques: indirect calorimetry and the 13C-bicarbonate method.

Research Methods

• Four Shetland ponies were used in this study. They were individually placed in respiration chambers for the measurements.
• The ponies were given either an oral or intravenous dose of 13C-labelled sodium bicarbonate. This substance helps in studying metabolic processes.
• The feeding time for the ponies was altered: they were fed haylage either three hours before, simultaneously with, or three hours after the administration of 13C-bicarbonate.
• Measurements of the carbon dioxide produced and oxygen consumed by the ponies were taken for six hours, following both administration methods of 13C-bicarbonate at all three feeding times.

Research Findings

• Findings showed that the feeding time significantly influenced the ponies’ carbon dioxide production and oxygen consumption. However, it had no impact on their respiratory quotient, measured via indirect calorimetry.
• The study also found that the recovery factor (the rate at which 13C was found in the ponies’ breath) was affected by the feeding times.
• The researchers found no difference between the indirect calorimetry and 13C-bicarbonate technique in estimating carbon dioxide production, indicating that both methods are reliable for such measurements.
• The energy expenditure estimated was found to be higher when food was offered during or after the measurements, compared to when no food was available before the measurements.

Conclusions and Recommendations

• The study concluded that feeding times do play a significant role in carbon dioxide production and energy expenditure in these ponies. This factor should be considered when using the 13C-bicarbonate technique in the field.
• The researchers recommended that future studies using horses should prefer intravenous administration of 13C-bicarbonate. This method would avoid complex 13C enrichment-time curves experienced with oral administration, thus making the analysis simpler and more accurate.