PATTERNS OF GROWTH AND ENERGY UTILIZATION OF THE DIET AFTER A PERIOD OF DIETARY RESTRICTION DURING THE WEANING PERIOD
A.P.R. Battochio; A.G. Santos; C.A.R. Coelho
Discipline of Pediatric Hepatology of the Department of Pediatrics of the School ofo Medicine of Botucatu - Unesp. Rubião Jr, s/n, cep:18618000, Botucatu – SP, Brazil.
Introduction: In rats, weaning may be a critical window for nutrition programming further body growth. There is a dietary change from rat milk containing a high proportion of fat to a diet low in fat and rich in proteins, carbohydrates and fibre.
Aim: to test if deficient diets during the weaning period in rats, from the 21rst post natal day (P21) to P28, would affect the pattern of growth during a period of free access to food from P29 to P70 as compared to breast fed animals.
Methods: Forty male Wistar rats were randomly allocated to one of four groupsr of ten animals each: Group 1(G1): ad libitum breast feeding in litters of six pups per dam; G2: standardized laboratory chow ad libitum; G3: food restriction receiving half of the food ingested by a pair fed animal in G2; G4: no lipid diet.
From P29 to P69, the standardized laboratory chow was fed ad libitum to all animals. The energy utilization rate (g/cal) from P29-P69 was calculated. The gain in weight from P29 to each four days after up to P70 was fitted to the Verhulst’s function. The third derivative of this function (a constant expressing the rate of variation in growth acceleration (g.d-2)) was estimated. The results were tested by a one factor ANOVA or Kruskall-Wallis test (p≤0.05) and when significant, the S.N.K method for multiple paired comparisons was employed.
Results: The median of the energy utilization of G3 was higher than that of all the other groups (G1:235 g/Cal, G2:250 g/Cal, G3:285 g/Cal, G4:261 g/Cal).
The medians of the rate of variation in growth acceleration (G1:-0.0013, G2:- 0.00089, G3:-0.00086, G4:-0.00089) of the groups G2, G3, and G4 were higher than G1 and were not significantly different one from the other.
Conclusions: Different diet restrictions had diverse effects on energy utilization and on the rate of variation in growth acceleration.
Key words: Nutritional programming; growth; young rats; dietary restrictions;
weaning.
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