The development of social dominance is affected by early protein malnutrition in rats.

Sebastião Sousa Almeida1* and Lucilla Maria Moreira Camargo2

ABSTRACT

Early protein malnutrition produces  structural and  functional alterations in the brain and  changes  the organism-environment  interactions. Rats from 26  to 56  days of age  were used  to study the effects of early postnatal protein malnutrition on the development of social dominance.  During lactation phase the litters were fed diet containing  16% protein (well-nourished) or 6% protein (malnourished). From weaning to the end of behavioral  tests well-nourished animals  were fed a  commercial  lab chow diet (well-nourished - W) and  the malnourished  rats were divided into 2 groups:  one  was maintained  on 6% protein diet (malnourished  - M) and the other was fed a commercial lab chow diet (previously malnourished - PM). Pairs of male rats of same diet conditions were tested, at different ages,  for three consecutive days. During sessions the pinning behavior (an indicator of social dominance) was recorded.  The results showed that both M and  PM animals were less efficient to establish social dominance  at earlier ages.  As M and PM animals turn older they increased  social dominance   index  indicating  developmental  retards.