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Metabolic changes and induction of hepatic lipidosis during feed restriction in llamas

Susan J. TornquistDepartment of Biomedical Sciences, College of Veterinary Medicine, Oregon State University, Corvallis, OR 97331-4802.

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Christopher K. CebraDepartment of Clinical Sciences, College of Veterinary Medicine, Oregon State University, Corvallis, OR 97331-4802.

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Robert J. Van SaunDepartment of Clinical Sciences, College of Veterinary Medicine, Oregon State University, Corvallis, OR 97331-4802.
Present address is Department of Veterinary Science, College of Agricultural Sciences, Pennsylvania State University, State College, PA 16802.

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Bradford B. SmithDepartment of Biomedical Sciences, College of Veterinary Medicine, Oregon State University, Corvallis, OR 97331-4802.

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John S. MattoonClinical Sciences, College of Veterinary Medicine, Oregon State University, Corvallis, OR 97331-4802.
Present address is Department of Veterinary Clinical Sciences, College of Veterinary Medicine, The Ohio State University, Columbus, OH 43210.

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Abstract

Objectives—To determine whether feed restriction induces hepatic lipidosis (HL) in llamas and to evaluate the metabolic changes that develop during feed restriction.

Animals—8 healthy adult female llamas.

Procedure—Llamas were fed grass hay at a rate of 0.25% of their body weight per day for 13 to 28 days. Llamas were monitored by use of clinical observation, serum biochemical analyses, and ultrasound-guided liver biopsies.

Results—All 8 llamas lost weight and mobilized fat. Five llamas developed HL, including 4 that were nursing crias. During the period of feed restriction, mean serum concentration of bile acids and activities of aspartate aminotransferase (AST), sorbitol dehydrogenase (SDH), and γ-glutamyl transferase (GGT) were significantly higher in llamas that developed HL, compared with llamas that did not. Mean insulin-to-cortisol concentration ratios were lower in llamas with HL before and up to 7 days of feed restriction, compared with those that did not develop HL.

Conclusions and Clinical Relevance—HL in llamas may be induced by severe feed restriction, particularly in the face of increased energy demand. Llamas with weight loss attributable to inadequate dietary intake may develop biochemical evidence of hepatopathy and HL. Increases in serum concentration of bile acids and activities of GGT, AST, and SDH may indicate the development of HL in llamas and identify affected animals for aggressive therapeutic intervention. (Am J Vet Res 2001;62:1081–1087)

Abstract

Objectives—To determine whether feed restriction induces hepatic lipidosis (HL) in llamas and to evaluate the metabolic changes that develop during feed restriction.

Animals—8 healthy adult female llamas.

Procedure—Llamas were fed grass hay at a rate of 0.25% of their body weight per day for 13 to 28 days. Llamas were monitored by use of clinical observation, serum biochemical analyses, and ultrasound-guided liver biopsies.

Results—All 8 llamas lost weight and mobilized fat. Five llamas developed HL, including 4 that were nursing crias. During the period of feed restriction, mean serum concentration of bile acids and activities of aspartate aminotransferase (AST), sorbitol dehydrogenase (SDH), and γ-glutamyl transferase (GGT) were significantly higher in llamas that developed HL, compared with llamas that did not. Mean insulin-to-cortisol concentration ratios were lower in llamas with HL before and up to 7 days of feed restriction, compared with those that did not develop HL.

Conclusions and Clinical Relevance—HL in llamas may be induced by severe feed restriction, particularly in the face of increased energy demand. Llamas with weight loss attributable to inadequate dietary intake may develop biochemical evidence of hepatopathy and HL. Increases in serum concentration of bile acids and activities of GGT, AST, and SDH may indicate the development of HL in llamas and identify affected animals for aggressive therapeutic intervention. (Am J Vet Res 2001;62:1081–1087)