Intergenerational protein deficiency and adolescent reproductive function of subsequent female generations (F1 and F2) in rat model

Background

Efficient reproductive function is an important characteristic that has evolved through natural selection. Nutrition can modulate reproductive activities at different levels, and its effect on reproduction is deemed complex and less predictable.

Objective

This study aims at investigating the underlying effect of persistent dietary protein deficiency during early life on reproductive parameters of subsequent (F₁ and F₂) generations.

Method

Rats in group of four (4) were fed daily, different ration of protein diet (PD) formulated as: 21% protein diet, 10%protein diet, 5%protein diet and control diet (rat chow, containing 16–18% protein). They were fed ad libitum before mating, throughout gestation and lactation, and next generations were weaned to the maternal diet. Reproductive function analysis (which include; gestation and pubertal hormonal profiling, onset of puberty, oestrus cyclicity, sexual response) and morphometric analysis of the ovarian structure were carried out to assess associated consequences.

Results

There was significant reduction in the fertility index (Control; 85.8%., 21%PD; 88.43%., as compared to 10%PD; 65.9%., 5%PD; 35.78%.,) at F_1, also recurring in F₂ respectively as a consequence of altered reproductive function in the protein deficient models at P ≤ 0.05. Low protein diet posed suboptimal intrauterine condition, which was linked to increased prenatal morbidity and mortality (control; 11.3%., 21%PD; 3.3%., 10%PD; 27.4%., 5%PD; 32.9%), low birthweight (control; 5.29, 4.9 g., 21%PD; 5.5, 5.06 g., 10%PD; 4.05, 3.86 g., 5%PD; 2.7, 2.5 g) at F₁ and F₂ respectively, delayed onset of puberty (with average pubertal age set at: control; PND 36, 21%PD; PND 38 while 10%PD; PND 62., and 5%PD; PND 67), followed by induced cycle irregularity, altered follicular maturation and endocrine dysfunction, more severe in 5%PD.

Conclusion

Reproductive status of a female organism depends on the maintenance of ovarian structure and function that has been associated with the hypothalamic pituitary-gonadal axis, hormonal events and sexual maturity. There is therefore an association between persistent early life protein deficiency and reproductive response which mechanistically involves life-long changes in key ovarian cytoarchitecture and function.