The Influence of High-Fat Diets on Estrous Cycles, Sperm Production and Fertility of Rats

Abstract

Numerous studies have related nutrition to reproduction (1-4), but only a few dealt with the effect of high-fat diets on reproduction and these were confined to the requirement of essential fatty acids for reproductive performance. Deuel et al. (5) and Sheer et al. (6) reported that rats fed diets containing high levels of fat had more rapid growth and more efficient reproductive and lactational performances than rats fed diets containing low concentrations of fats. However, French et al. ( 7 ) found decreased reproductive performance of rats when the diet contained 23% corn oil compared to 4.470; the animals fed the high-fat diet produced smaller offspring, but lactational capacity was similar in the two groups of animals.Richardson et al. (8) reported that the number of young weaned by female rats was essentially the same when they were fed diets containing 3-18% fat, but was decreased when the diet contained 25740 fat.In the work reported herein, several reproductive parameters were measured in male and female rats fed a high (40%) fat diet ad libitum or restricted to give body weights similar to control rats fed a grain diet. In another experiment female rats were fed diets containing either 2.7 or 60% fat.Procedures. Rats in three experiments were 1Michigan Agric. Exp. Sta. J. article number 6183. Supported in part by an NIH gnant HD 05402-03 Ssl . housed individually in an animal quarter maintained at about 22' with 1 2 hr of light and 12 hr of darkness. Weanling female Osborne-Mendel rats were used in Expts 1 and 2, and weanling male Sprague-Dawley in Expt 3. Water was available at all times. The duration of the dietary treatments and numbers of rats used for the first and second experiment are indicated in Figs. 1 and 2, respec tively .In the (first experiment, rats were assigned at random to one of three groups, and fed a 40% fat diet4 ad libitum, or the same diet ad libitum until the rats reached 250-g body weight when feed intakes were restricted or a grain diet5 was offered on an ad libitum basis. Rats fed the restricted high-fat diet were fed to maintain body weight gain similar to grain-fed rats; usually this required 8-9 g of high-fat diet/rat/day.In the second experiment, rats were fed ad libitum a diet6 containing 2.7% fat or a 440% high-fat diet cornposition (in %): Fat, 40) ; casein, 25 ; mineral mix (Wesson, General Biochelmicals, Chagrin Falls, Ohio), 5 ; vitamin mix (vitamin fortification mixture, Nutritional Biochemicals, Cleveland, Ohio), 2.2 ; non-nutritive fiber, 2 ; aureomycin, 0.01 ; liver powder, 2 ; DL-methionhe, 0.25; sucrose, 23.54. For those fed restricted mlounts of this diet the % of 'casein was increased to 30 anld sucrose decreased to 118.54. This was to assure that the restricted rats had adequate proltein intake. 5 Grain diet is la nutritionally adequate diet maide primarily firom a corn-soy mixture (composition described in this journal, Vol. 130, p. 11146, footnote 1, 1969). 62.7% low fat diet composition (in %): Corn oil, 2.7; casein, 2 5 ; minerd mix (Weson, GeneralBi...

Leptin accelerates the onset of puberty in normal female mice.

“…Earlier studies suggested that fat-derived signals (e.g., fatty acids and estrogen) (11,29,30) could link adiposity and reproduction, while Wade et al (31) have proposed instead that glucose is the metabolic signal involved in the central regulation of reproduction. Since concentrations of the fat-derived hormone, leptin, correlate with adipose tissue mass in the fed state (16-18) and leptin levels fall with starvation (17,19), leptin could provide the relevant information to the brain.…”

Body weight and food intake at early estrus of rats on a high-fat diet.

“…Weight growth in the rat has been reported to be more rapid on high-fat diets than on normal or low-fat diets (3)(4)(5). Female rats on high-fat diets, therefore, should have vaginal opening and estrus earlier than on a low-fat diet.…”

Guidance Notes for Analysis and Evaluation of Chronic Toxicity and Carcinogenicity Studies

“…Diet, food and water consumption and body weight gains per se can also have an important influence on many aspects of animal responses, including shifts in metabolic, hormonal and homeostatic mechanisms (Kennedy, 1969), disease processes (Berg & Simms, 1960;Paynter, 1984;Ross & Bras, 1965;Tannenbaum, 1940;Cohen et al, 1994) and maturation (Innami et al, 1973). (See also Subsection 1.2.2.)…”