Effect of Life-Long Dietary <i>n</i>-6/<i>n</i>-3 Fatty Acid Ratio on Life Span, Serum Lipids and Serum Glucose in Wistar Rats

Abstract

Summary Types of dietary lipid affect the life span of rats. In this study, we investigated the influence of the life-long dietary n -6/ n -3 ratio on life span and serum lipid and glucose levels. A semi-purified diet adjusted to a constant saturated : monounsaturated : polyunsaturated fatty acid ratio and an n -6/ n -3 ratio of 1 (R1), 4 (R4) or 16 (R16) was fed to rats ( n ϭ 33) from 4 wk of age until death. There were no significant differences in the food intake or body weight, nor were there survival curve or mean life span variations among the 3 groups. The serum cholesterol levels after feeding the test diet for 6 and 12 mo were significantly lower in the R1 group than in the other groups, and the serum triacylglycerol levels were significantly lower than those in the R16 group. However, no significant differences were noted in the serum cholesterol or triacylglycerol level after feeding for 18 mo among the 3 groups. A significantly higher serum glucose level was noted in the R1 group only at 18 mo of test diet ingestion, compared to that in the R4 group. The results suggest that the influence of the dietary n -6/ n -3 ratio on the serum lipid and glucose levels varies, depending on the duration and life stage of feeding. Our findings further suggest that the life span of Wistar rats is not affected even if the ratio of dietary n -6/ n -3 changes from 1 to 16.

Time‐course of changes in the myonuclear domain during denervation in young‐adult and old rat gastrocnemius muscle

“…The environment was maintained at 22°C on a 12‐h light/12‐h dark cycle. The 5‐month‐old (young‐adult) rats have ended their main growth spurt and are mature, whereas the 25‐month‐old rats are considered old; the Wistar rat has a median lifespan of 21.5 months (Harlan Laboratories, Indianapolis, Indiana) and a mean life expectancy of around 24 months 29, 30. Rats were randomly assigned to groups in which the left gastrocnemius muscle was subjected to 1, 2, or 4 weeks of denervation, whereas the right gastrocnemius muscle served as an internal control, as described previously 9.…”

Effect of Dietary Lipids on Longevity and Memory in the SAMP8 Mice

“…Takeuti et al showed that variation in the n-6/n-3 dietary ratio between 1 and 16 did not affect Wistar rat life-span (20). Indeed, no consistent findings have been reported with regard to the influence of dietary fat on life-span.…”

“…The mice were subjected to step-through passive avoidance tests as described in a prior study ( 20 ). The cage [35 ϫ 17 ϫ 20 cm (width ϫ length ϫ height), model E10-15; Coulbourn Instruments] consisted of two equal compartments connected by a small guillotine door (7.5 ϫ 6.5 cm guillotine door, model E10-15GD; Coulbourn Instruments).…”