CONSUMPTION OF A HIGH-FAT DIET IMPAIRS REPRODUCTIVE-PERFORMANCE IN SPRAGUE-DAWLEY RATS

Rats made obese by cafeteria feeding have poor reproductive outcomes. To investigate this phenomenon in animals fed a more nutritionally ade quate diet, female rats were fed either a high fat (HF) (modified AIN- 76A(TM), 35 g fat/100 g diet) or a control (C) (AIN-76A(TM), 5 g fat/1 00 g diet) diet, beginning at 27 d of age. To assess reproductive perf ormance, rats were studied at d 0, 5 and 18 of pregnancy and on d 3 of lactation. Pregnancy rates were significantly (P < 0.001) lower in th e high fat-fed rats than in the control-fed rats (56.4 and 89.1%, resp ectively). There was no difference between groups in total pregnancy w eight gain or the proportion of weight gained during pregnancy that wa s retained by the dam. High fat-fed dams tended to gain weight more ra pidly early in gestation than control-fed dams and then less rapidly t han control-fed dams during the last week of gestation. Litter number and pup weight at birth did not differ between groups, but of high fat -fed pups had significantly higher (P < 0.04) mortality rates than pup s of control-fed dams (16.5 and 7.7%, respectively) over the first 3 d of life. Control-fed dams experienced the expected reduction (P < 0.0 5) in plasma insulin concentrations between the end of pregnancy and e arly lactation, but high fat-fed dams did not. Thus, physiological mec hanisms controlling distribution of metabolic fuels may not be functio ning properly in high fat-fed dams. Therefore, consuming a high fat di et reduces a rat's capacity to conceive and ability to maintain her li tter during the perinatal period.