The role of body size in climbing and locomotor behavior of protein-malnourished and well-nourished rats
✍ Scribed by Robert D. Hall
- Publisher
- John Wiley and Sons
- Year
- 1984
- Tongue
- English
- Weight
- 935 KB
- Volume
- 17
- Category
- Article
- ISSN
- 0012-1630
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✦ Synopsis
Behavioral comparisons of malnourished and well-nourished rats often involve animals of different sizes-even after rehabilitation of malnourished animals. The role of body size in two kinds of behavior affected by early malnutrition was investigated. Rats subjected to protein restriction during the preweaning period (LH) or during the pre-and postweaning periods (LL) climbed more than wellnourished rats (HH) at the ages of 35-225 days. This difference reflected differences in body weight; at comparable body weights LH and LL rats climbed no more than HH rats. Females climbed more than males, which also reflected differences in size, but decreases with age did not depend entirely on gowth. LH rats were more active in running wheels than HH rats. For both LH and LL rats, the overall changes with diet and age resembled those in climbing, except that the effects of sex, but not age, were partly independent of size.
In recent years there has been a great deal of research concerned with the effects of malnutrition or undernutrition during the early stages of development on the brain and behavior of the laboratory rat. In much of this work, behavioral comparisons of malnourished and well-nourished rats have necessarily involved animals of different sizes because the stunting effects of early deprivation can persist for many months-even when rehabilitation is begun at weaning or shortly thereafter (see, for example, Widdowson & McCance, 1960). In only a few studies that I am aware of (e.g., Whatson, Smart, & Dobbing, 1976) has there been an attempt to control for differences in body size or to evaluate the contribution of that variable to behavioral differences between malnourished and wellnourished rats. This is not surprising, perhaps, in view of the fact that the role of body size in the behavior of the normal rat has received scant attention except in research more or less directly concerned with body weight and its regulation.
This investigation began with two general questions: Is body size an important factor in the behavior of the rat, especially in those kinds of behavior reported to differ in malnourished and well-nourished rats? If so, does that factor help to account for the reported diet-related differences? Some preliminary observations of many kinds of behavior suggested that climbing would be a convenient behavior to study initially, as a kind of model for such studies, because marked reductions in the amount of climbing occurred