Reproductive performance and gestational effort in relation to dietary fatty acids in guinea pigs

Abstract

Background: Dietary saturated (SFAs) and polyunsaturated (PUFAs) fatty acids can highly affect reproductive functions by providing additional energy, modulating the biochemical properties of tissues, and hormone secretions. In precocial mammals such as domestic guinea pigs the offspring is born highly developed. Gestation might be the most critical reproductive period in this species and dietary fatty acids may profoundly influence the gestational effort. We therefore determined the hormonal status at conception, the reproductive success, and body mass changes during gestation in guinea pigs maintained on diets high in PUFAs or SFAs, or a control diet.

Results: The diets significantly affected the females' plasma fatty acid status at conception, while cortisol and estrogen levels did not differ among groups. SFA females exhibited a significantly lower body mass and litter size, while the individual birth mass of pups did not differ among groups and a general higher pup mortality rate in larger litters was diminished by PUFAs and SFAs. The gestational effort, determined by a mother's body mass gain during gestation, increased with total litter mass, whereas this increase was lowest in SFA and highest in PUFA individuals. The mother's body mass after parturition did not differ among groups and was positively affected by the total litter mass in PUFA females.

Conclusions: While SFAs reduce the litter size, but also the gestational effort as a consequence, PUFA supplementation may contribute to an adjustment of energy accumulations to the total litter mass, which may both favor a mother's body condition at parturition and perhaps increase the offspring survival at birth.

Keywords: Body mass; Female reproduction; Gestation; Litter size; Polyunsaturated fatty acid; Saturated fatty acid; Total litter mass.

Fig. 1

Mean body mass in female guinea pigs maintained on a control, high-PUFA, or high-SFA diet during gestation and after parturition. Circles represent the body mass for each group and day (mean ± s.e.m.); lines for gestation (day 0 to 65) represent the mean fitted values of a linear mixed effect model (corrected for repeated measurements) on the body mass change, including the second-order polynomial term for day and the total litter mass as covariate. Sample sizes: control n = 10, PUFA n = 8, SFA n = 10. ** P ≤ 0.01 comparing SFA and the remaining groups. Group:day effect during gestation: P ≤ 0.05

Fig. 2

Effect of total litter mass on the body mass gain during gestation in guinea pig females maintained on a control, high-PUFA, or high-SFA diet. Effects were extracted from a linear mixed effect model and are shown for a total litter mass of 100 g and 600 g, respectively. Sample sizes: control n = 10, PUFA n = 8, SFA n = 10. Group:day:total litter mass: p ≤ 0.05

Fig. 3

Effects of total litter mass on body mass in guinea pig females maintained on a control, high-PUFA, or high-SFA diet. Effects are corrected for the body mass at conception. a Effects on body mass prior to parturition. Control: p ≤ 0.001, PUFA: p ≤ 0.001, SFA: p ≤ 0.001; control vs. PUFA: n.s., control vs. SFA: n.s., PUFA vs. SFA: p ≤ 0.05. b Effects on body mass after parturition. Control: n.s., PUFA: p ≤ 0.05, SFA: n.s.; all group comparisons: n.s. (n.s.: not significant)