Calorie Restriction Modulates Reproductive Development and Energy Balance in Pre-Pubertal Male Rats.

Guilherme Rizzoto,Deepa Sekhar,Prasanth K Chelikani,Jacob C Thundathil,John P Kastelic

doi:10.3390/nu11091993

Abstract

The objective was to determine effects of feed restriction and refeeding on reproductive development and energy balance in pre-pubertal male rats. Sprague Dawley rats (n = 32, 24 days old, ~65 g), were randomly allocated into four treatments (n = 8/treatment): (1) Control (CON, ad libitum feed; (2) Mild Restriction (MR, rats fed 75% of CON consumption); (3) Profound Restriction (PR, 50% of CON consumption); or (4) Refeeding (RF, 50% restriction for 14 days, and then ad libitum for 7 days). Feed restriction delayed reproductive development and decreased energy balance and tissue accretion, with degree of reproductive and metabolic dysfunctions related to restriction severity. In RF rats, refeeding largely restored testis weight, sperm production (per gram and total), plasma IGF-1, leptin and insulin concentrations and energy expenditure, although body composition did not completely recover. On Day 50, more CON and RF rats than PR rats were pubertal (5/6, 4/5 and 1/6, respectively; plasma testosterone >1 ng/mL) with the MR group (4/6) not different. Our hypothesis was supported: nutrient restriction of pre-pubertal rats delayed reproductive development, induced negative energy balance and decreased metabolic hormone concentrations (commensurate with restriction), whereas short-term refeeding after profound restriction largely restored reproductive end points and plasma hormone concentrations, but not body composition.

Highlights

Calorie restriction is a dietary regimen that reduces intake (20–40% reduction in calories compared to ad libitum consumption) without causing malnutrition [1], but reducing incidence of a variety of diseases, e.g., diabetes, cancer and autoimmune diseases [2]
24, they were randomly allocated into four treatment groups (n = 8 per group): (1) Control (CON, ad libitum access to feed); (2) Mild Restriction (MR, rats fed 75% of diet consumed by CON); (3) Profound Restriction (PR, rats fed 50% of diet consumed by CON); and (4) Refeeding (RF, 50% restriction for 14 days and switched to ad libitum for seven days)
Effects of nutrition on reproductive traits are well known in ruminants, swine and mice [9,29,30], e.g., reproductive and metabolic adaptations to calorie restriction during the peri-pubertal period remain largely unknown

Summary

Introduction

Calorie restriction is a dietary regimen that reduces intake (20–40% reduction in calories compared to ad libitum consumption) without causing malnutrition [1], but reducing incidence of a variety of diseases, e.g., diabetes, cancer and autoimmune diseases [2]. Long-term calorie restriction or short-term starvation (fasting) reduces body weight and maximizes lifespan of rodents [3]. Calorie restriction can have adverse effects on male reproduction, including reductions in sperm production, testis size, diameter of seminiferous tubules and sperm quality [4]. Nutrient restrictions in females reduce fertility [8], decreasing the probability of establishing and supporting a pregnancy when nutrient resources are deficient. Subsequent access to ad libitum refeeding restores reproductive performance [9]

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Conclusion