Journal article

Publication year: 2000

Pages: 65-73

Journal: Journal of Animal Physiology and Animal Nutrition

Volume number: 83

Issue number: 2

ISSN: 0931-2439

DOI Link: https://doi.org/10.1046/j.1439-0396.2000.00230.x

Publisher: Wiley

Abstract: 
Recent studies demonstrated that zinc deficiency produces a fatty liver in rats that were fed diets with high levels of saturated fatty acids. In order to clarify the reasons of this phenomenon, the present study investigated the effect of zinc deficiency on the lipogenesis in the liver and the lipolysis in adipose tissue. Therefore, rats were fed zinc-adequate (40 mg Zn/kg) or zinc-deficient diets (0.8 mg/kg) with either a mixture of coconut oil and soybean oil (85 : 15, w/w, 'coconut oil diet') or a mixture of salmon oil and soybean oil (85:15, w/w, 'fish oil diet'). In order to avoid a reduced feed intake by zinc deficiency, all the rats were fed sufficient quantities of diet by gastric tube. All of the animals receiving the zinc-deficient diets exhibited reduced body weight gain as well as reduced zinc concentrations and activities of alkaline phosphatase in serum proving their zinc-deficient status. Zinc-deficient rats fed the coconut oil diet developed a fatty liver characterized by markedly increased concentrations of triacylglycerols. Those animals also had markedly increased activities of hepatic lipogenic enzymes and increased concentrations of free fatty acids in serum compared with zinc-adequate rats that were fed the coconut oil diet. Thus, the fatty liver might be due to increased de-novo synthesis of fatty acids and to increased uptake of free fatty acids from blood into the liver. Increased concentrations of free fatty acids in serum suggest an increased race of lipolysis in adipose tissue; however, the activity of hormone-sensitive lipase in epidydimal adipose tissue was not increased in zinc-deficient rats fed coconut oil compared with zinc-adequate rats fed coconut oil. In the rats that were fed the fish oil diet, zinc deficiency caused only moderately increased concentrations of triacylglycerols in the liver, and thus did not produce a fatty liver. This is consistent with the activities of lipogenic enzymes which were generally low by feeding the fish oil and were only moderately increased by zinc deficiency in the rats that were fed the fish oil diet. Furthermore, zinc-deficient rats that were fed the fish oil diet did not exhibit significantly increased concentrations of free fatty acids although those rats had an increased activity of hormone-sensitive lipase in epidydimal adipose tissue. In conclusion, the study shows that zinc deficiency enhances hepatic lipogenesis and lipolysis in adipose tissue; however, the magnitude of those effects is influenced by the type of dietary fat.

Harvard Citation style: Eder, K., Wild, S. and Kirchgeßner, M. (2000) Zinc deficiency and activities of enzymes involved in lipogenesis and lipolysis in rats fed diets with coconut oil or fish oil, Journal of Animal Physiology and Animal Nutrition, 83(2), pp. 65-73. https://doi.org/10.1046/j.1439-0396.2000.00230.x

APA Citation style: Eder, K., Wild, S., & Kirchgeßner, M. (2000). Zinc deficiency and activities of enzymes involved in lipogenesis and lipolysis in rats fed diets with coconut oil or fish oil. Journal of Animal Physiology and Animal Nutrition. 83(2), 65-73. https://doi.org/10.1046/j.1439-0396.2000.00230.x