Evaluation of Feeding Beta-Hydroxy-Beta-Methylbutyrate (HMB) to Mouse Dams during Gestation on Birth Weight and Growth Variation of Offspring

SIMPLE SUMMARY: In litter-bearing species, fetal competition during pregnancy can decrease the availability of nutrients to some offspring, which can increase the prevalence of low body weight at birth and variability of birth weights. Low birth weight can increase the chance of death early in life and compromise lifetime growth and health. This study was designed to evaluate the efficacy of a nutritional intervention, β-hydroxy-β-methylbutyrate (HMB), to improve uniformity of birth weight in mice. Mice received HMB at low and high doses and during a critical time during pregnancy. Dietary HMB did not influence average birth weight, uniformity of birth weight, growth performance, or body composition of mouse pups born to dams fed HMB during pregnancy. In our mouse model, dietary HMB fed to pregnant mice did not reduce prevalence of low-birth-weight offspring. ABSTRACT: This study was designed to determine if feeding β-hydroxy-β-methylbutyrate (HMB) to pregnant mice would improve birth weight uniformity and growth performance of offspring. Dams (Agouti A(vy)) were assigned to one of four treatments: control (CON; n = 13), low-level HMB (LL; 3.5 mg/g; n = 14), high-level HMB (HL; 35 mg/g; n = 15), and low-level pulse dose fed from gestational days 6 to 10 (PUL; 3.5 mg/g; n = 14). Randomly selected dams (n = 27) were euthanized on gestational day 18 to collect placentae and pup weights. The remaining dams gave birth and lactated for 28 days. Dams only received HMB during gestation. Dietary HMB did not influence the performance of dams. Dietary treatment during gestation did not affect litter size or birth weight of pups. Variation was not different among treatments in terms of birth weight of offspring. Placental weights were not affected by treatments. Overall, growth performance of offspring after weaning was similar among all treatments. Body composition of offspring at 5 and 8 weeks of age was similar regardless of HMB treatment during gestation. In conclusion, dietary HMB supplementation in pregnant mice did not affect birth weight, variations in birth weight, or growth performance of offspring.