Preileal digestibility of coconut fat and soybean oil in horses and their influence on metabolites of microbial origin of the proximal digestive tract.

This study assesses the preileal digestibility of coconut fat and soybean oil in horses to understand how they may impact microbial metabolites in the digestive tract. Findings suggest fat feeding significantly stimulates the jejunoileal flow of chyme and improves fat digestibility, while reducing lactic acid and short-chain fatty acids concentration in chyme.

Study’s Methodology

• The researchers used three horses, each about 190 kg in body weight and fitted with a permanent fistula at the end of the jejunum.
• The horses were fed a control diet consisting of one-third hay and two-thirds mixed feed to which either soybean oil or coconut fat was added at two different levels. This resulted in fat intakes ranging from 0.1 g (control diet) to 0.5 or 1 g per kg of body weight.
• Each experimental period consisted of 2 weeks of adaptation, 2 days of breath tests taken before and every hour after the morning meal, and a further 5 days of sampling chyme, the semi-fluid mass of partly digested food in the small intestine.
• The chyme was analyzed for its content of crude fat, crude protein, organic acids (short-chain fatty acid [SCFA], lactic acid), pH, and minerals like calcium, magnesium, and phosphorus. Hydrogen (H2) and methane (CH4) levels were determined in the expired air.

Key Findings

• The study found that fat feeding significantly stimulated the flow of chyme in the jejunum and ileum, parts of the horse’s intestine, regardless of the type or amount of fat added to the diet.
• There was a significant increase in preileal fat digestibility from 30-38% in the control periods to between 73-80% for moderate fat intake and 82-86% for high fat intake.
• The researchers reported a reduction in lactic acid as well as SCFA concentrations in chyme. This reduction was dose-dependent and occurred 5 hours after feeding (postprandial).
• Fat intake led to a drop in the hydrogen concentration of exhaled air, but this did not significantly affect the concentration of methane, except with high levels of soybean oil that slightly reduced methane levels.
• The researchers reported that the addition of fat had no significant effect on the absorption of magnesium and calcium, but there was a significant increase in the secretion of phosphorus.
• They also found that the digestibility of protein slightly decreased due to the inclusion of fat in the diet.

Implication of Research

• The research suggests that fat from coconut or soybean oil fed to horses stimulates their digestive process and aids the digestion of fats.
• It also shows potential implications for the use of dietary fat in managing the fermentation processes in the horse’s gut, as evidenced by the reduction of lactic acid and short-chain fatty acid concentrations in the chyme.
• The authors point out that even though fat inclusion led to a slight decrease in protein digestibility, the effects on overall nutrient absorption and phosphorus secretion may require additional research for a comprehensive understanding.