Cm. Dwyer et Nc. Stickland, SUPPLEMENTATION OF A RESTRICTED MATERNAL DIET WITH PROTEIN OR CARBOHYDRATE ALONE PREVENTS A REDUCTION IN FETAL MUSCLE-FIBER NUMBER IN THE GUINEA-PIG, British Journal of Nutrition, 72(2), 1994, pp. 173-180
A 60% reduction in maternal feed intake is known to cause a reduction
of approximately 20% in biceps brachii fibre number in the guinea-pig
fetus. This investigation was designed to isolate the dietary componen
t responsible by reducing all dietary components to 60% of the ad lib.
level and supplementing the protein, carbohydrate or fat component to
the level of the ad lib. intake. Fetal muscles were examined at 50 d
gestation to determine numbers of primary and secondary fibres, and at
term to determine total fibre number. Fetal and neonatal weights were
reduced in all restricted groups (P < 0.05) when compared with ad lib
. controls. At term this reduction was significantly less (P < 0.05) i
n the protein-supplemented group (20%) than in the 60%-restricted and
fat-supplemented groups (43%) and the carbohydrate-supplemented group
(34%). Biceps brachii fibre numbers were reduced in the 60%-restricted
and fat-supplemented groups by 14-16%, but fibre numbers were similar
in control, protein-supplemented and carbohydrate-supplemented groups
. Any reduction in fibre number was in the secondary fibre component o
f total fibre number. Therefore, biceps brachii fibre numbers were red
uced only when maternal diets were deficient in both protein and carbo
hydrate.