Digestive enzyme concentrations and activities in healthy pancreatic tissue of horses.

This study examines the levels and activities of primary digestive enzymes in the healthy pancreatic tissue of horses. Surprisingly, the research showed that lipase, an enzyme responsible for fat digestion, had the highest concentration, which may give insights into why horses can tolerate high-fat diets despite carbohydrates being their primary energy source.

Methodology

• Seven adult horses with healthy pancreatic tissues were the subjects of this research.
• Small samples of their pancreatic tissues were collected immediately after euthanasia, rapidly frozen in liquid nitrogen, and stored at an extremely cold temperature (-80 degrees Celsius) until required for analysis.
• The study focused on measuring the concentrations and activities of five key digestive enzymes: amylase, lipase, chymotrypsin, trypsin, and elastase. These elemental assays were carried out using a microtiter technique, which allows for simultaneous analysis of multiple samples.
• The research also determined the relative concentration of pancreatic proteins by using bovine serum albumin as a reference standard.
• Additionally, pancreatic DNA was extracted and its concentration was measured by using the diphenylamine method, with calf thymus DNA serving as a standard.

Results

• The study presented that the concentration of each of these enzymes, measured in units per milligram of DNA, was consistent among all horses.
• The concentration of lipase, an enzyme that breaks down fat, was highest (1,090.8 +/- 285.3 U/mg of DNA).
• Following lipase, the concentration of amylase, which aids in complex carbohydrate digestion, was next (59.5 +/- 9.8 U/mg of DNA).
• Enzymes elastase, trypsin, and chymotrypsin, all responsible for protein breakdown, were found in significantly smaller concentrations (1.9 +/- 0.6, 3.5 +/- 1.5, and 9.6 +/- 2.9 U/mg of DNA, respectively).

Conclusions

• The researchers found these results unexpected due to the typical equine diet which is predominantly carbohydrate-based, suggesting the digestion system should favour enzymes for carbohydrate breakdown instead of fat digestion.
• However, the unusually high concentration of lipase may explain why horses adapt well to high-fat diets. This evidence challenges the existing perception about the diet and digestive system of horses, potentially opening up new avenues in equine dietary science and management.