High Consumption of Lard and Fructose Modulates Larval Pupation and Stress Resistance in Drosophila Melanogaster Adults

Obesity and metabolic syndrome are becoming the number one health problem in modern society. Unhealthy diet with sedentary life style are considered to be the main causes of obesity. Food with excessive fat and fructose play an important role here. The aim of this work was to study the effects of feeding with lard, as a source of fat, or fructose, as a source of carbohydrates, on physiological and biochemical parameters of the fruit fly Drosophila melanogaster Canton S. The addition of 10% lard to the basic medium containing 5% fructose inhibited pupation of Canton S larvae. Medium with 15% fructose did not affect larval pupation rate. One-week feeding with medium containing 10% lard reduced climbing activity in 9-day-old Canton S males. In addition, food with 15% lard reduced climbing activity in female flies. One-week feeding with high fructose medium (15% fructose) did not affect climbing activity of flies of both sexes. Both high calorie diets, with lard and fructose, significantly increased the resistance of males to cold stress (measured by reducing time required for recovery from chill coma), but reduced heat stress resistance (determined by faster onset in heat coma at 40°C) in both sexes. The resistance of insects to starvation was reduced on high lard medium but not on fructose one. Foods enriched with fructose or lard did not affect food consumption, body masses and triacylglyceride content and levels of low- and high-molecular thiols in 9-day-old of flies of both sexes. In addition, feeding with high lard resulted in a downward trend in lower glucose and glycogen levels, whereas high fructose had the opposite effects. Thus, foods with high fructose and lard modulated stress resistance in adult flies and may affect energy metabolism. Detailed mechanisms underlying physiological effects of high fructose and lard in Drosophila needs further research.