Digestive enzyme concentrations and activities in healthy pancreatic tissue of horses

Mireia Lorenzo-Figueras Island Whirl Equine Colic Research Laboratory, Department of Large Animal Clinical Sciences, College of Veterinary Medicine, University of Florida, Gainesville FL 32601

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Sophie M. Morisset Department of Clinical Sciences, Faculty of Veterinary Medicine, University of Montreal, St Hyacinthe, PQ J2S 2M2, Canada

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Jean Morisset Division of Gastroenterology, Faculty of Medicine, University of Sherbrooke, Sherbrooke, PQ J1H 5N4 Canada

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Jean Lainé Division of Gastroenterology, Faculty of Medicine, University of Sherbrooke, Sherbrooke, PQ J1H 5N4 Canada

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Alfred M. Merritt Island Whirl Equine Colic Research Laboratory, Department of Large Animal Clinical Sciences, College of Veterinary Medicine, University of Florida, Gainesville FL 32601

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Abstract

Objective—To measure concentrations and activities of major digestive enzymes in healthy equine pancreatic tissue.

Animals—7 adult horses with normal pancreatic tissues.

Procedures—Small pieces of pancreatic tissue were collected immediately after euthanasia, immersed in liquid nitrogen, and maintained at −80°C until analyzed. Concentrations and activities of amylase, lipase, chymotrypsin, trypsin, and elastase were determined by use of a microtiter technique. Relative pancreatic protein concentrations were determined by use of bovine serum albumin as the standard. Pancreatic DNA was extracted and con-centrations determined by use of the diphenylamine method with calf thymus DNA as the standard.

Results—The pancreatic cellular concentration of each enzyme, expressed as units per milligram of DNA, was consistent among horses. Cellular concentration of lipase (1,090.8 ± 285.3 U/mg of DNA) was highest, followed by amylase (59.5 ± 9.8 U/mg of DNA). Elastase, trypsin, and chymotrypsin were detected in small concentrations (1.9 ± 0.6, 3.5 ± 1.5, and 9.6 ± 2.9 U/mg of DNA, respectively). Similar results were obtained for specific activities of the enzymes.

Conclusions and Clinical Relevance—Results were unexpected because, under natural conditions, the predominant energy source for horses is carbohydrate. These results may indicate, in part, the reason horses seem to tolerate large amounts of fat added to their diet.

Abstract

Objective—To measure concentrations and activities of major digestive enzymes in healthy equine pancreatic tissue.

Animals—7 adult horses with normal pancreatic tissues.

Procedures—Small pieces of pancreatic tissue were collected immediately after euthanasia, immersed in liquid nitrogen, and maintained at −80°C until analyzed. Concentrations and activities of amylase, lipase, chymotrypsin, trypsin, and elastase were determined by use of a microtiter technique. Relative pancreatic protein concentrations were determined by use of bovine serum albumin as the standard. Pancreatic DNA was extracted and con-centrations determined by use of the diphenylamine method with calf thymus DNA as the standard.

Results—The pancreatic cellular concentration of each enzyme, expressed as units per milligram of DNA, was consistent among horses. Cellular concentration of lipase (1,090.8 ± 285.3 U/mg of DNA) was highest, followed by amylase (59.5 ± 9.8 U/mg of DNA). Elastase, trypsin, and chymotrypsin were detected in small concentrations (1.9 ± 0.6, 3.5 ± 1.5, and 9.6 ± 2.9 U/mg of DNA, respectively). Similar results were obtained for specific activities of the enzymes.

Conclusions and Clinical Relevance—Results were unexpected because, under natural conditions, the predominant energy source for horses is carbohydrate. These results may indicate, in part, the reason horses seem to tolerate large amounts of fat added to their diet.

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