Growth and body composition in low-body weight rats: influence of dietary fat.

SUAREZ C; FERREIRA MONTEIRO AG; MACRI V; RAMOS C; GONZALES CHAVES M; PELLEGRINI G; RODRIGUEZ P; ZENI SN; FRIEDMAN SM

EEUU

Congreso; FASEB 2009; 2009

FASEB

Previous studies demonstrated the relationship between dietary fat and body composition. However, we studied the hypothesis that body weight (BW) of the infant, would influence body composition.  At weaning female Wistar rats (n=72) were grouped according to BW (aged=21 day) as follows: control (C, n=31) >33.5 g BW and experimental (E, n=35) <33.5 g BW. C received a diet containing 7% w/w of fat (AIN-G) and E was fed one of 2 diets; E1 (n=20), fat=7% w/w (AIN-G) and E2 (n=15), fat=15% w/w. At aged 28, 35 and 49 (t28, t35 and t49, respectively), 8 rats per group were sacrificed. BW and % body fat and total skeleton body mineral content (BMC,mg) by DEXA (Lunar DPX-L) were evaluated. Body gain velocities (BGV) within times were calculated. BMC was analyzed per BW-0.75. Results (mean±SE) assessed by ANOVA and Dunnett test. At t28 and t35, CBW was higher than E (p<0.001) despite BGV in E groups was increased as compared to C (p<0.001). From t35, only E1 showed higher BGV (p<0.01). Body fat % and BMC/ BW-0.75  did not show significant differences throughout experimental period. Conclusion: We speculate that in low-body weight individuals, dietary fat equal to RDA may be insufficient to achieve body size proportions, leading to a delayed in growth rate; meanwhile % body fat and BMC related to  BW-0.75  appears to be in proportion to BW. Awarded by UBACyT O 004 and O015.