The effect of rehabilitation at different stages of development of rats marginally malnourished for ten to twelve generations

Abstract

I . Rats which have been maintained for ten to twelve generations on diets of low protein value were rehabilitated in utero (group P), from birth (group F) and from 4 weeks of age (group W).2. Group W showed little change in physique, behaviour or learning, indicating that for recovery to be effective refeeding must begin earlier.3. Group F just failed to attain full physical recovery (90%) whereas group P overgrew by 18.6% in weight and 8.5 O; in length. 4.In a test designed to evaluate learning ability rehabilitated rats of groups P and F were significantly less successful than normal rats, but more successful than rats of group W or rats of the original undernourished colony. .Rehabilitation for a further two generations in groups F and P corrected any residual physical and behavioural defects but produced no further improvement on the Lashley ( I 938) jumping platform.The changes produced in rats by several generations of marginal protein-energy deficiency have been reported earlier (Stewart, 1970;Stewart & Sheppard, 1971; Stewart e f al. 1975). There would appear to be a rapid adaptation in size and shape which stabilizes after two or three generations at a level probably controlled by the severity of the dietary deficiency. The adult males of the deficient colonyweighed approximately40 yo less than thewell-fedcontrols, and the females 30 yo less. Body lengths were reduced by 12 and 8 yo respectively and this was also the deficit in femur length. Brain weights were reduced by approximately 4-5 %.

The intergenerational effects of fetal programming: non-genomic mechanisms for the inheritance of low birth weight and cardiovascular risk

“…However, the accidental introduction of less-palatable food, which resulted in a period of self-imposed calorie restriction in the 'control' animals, also provides evidence that poor nutrition in one generation can produce effects on birth weight in subsequent generations. This effect was confirmed in further experiments when a number of animals from the malnourished colony weaned onto the control diet did not achieve an adult size equivalent to that of the control animals for three further generations (Stewart et al 1980).…”

“…Such effects may also be mediated, or indeed amplified, by adverse environmental conditions persisting across a number of generations. In animal models, second generation effects have been noted following impaired nutrition in utero, and exposure during specific time-windows of development may be important (Stewart et al 1975, 1980, Laychock et al 1995, Hoet & Hanson 1999, Martin et al 2000. However, these occur even when nutrition is normal in the F2 generation, so that perpetuation of the insult may not be required to express the effect in later generations.…”

Intergenerational effects of birth weight on glucose tolerance and reproductive performance

“…Rats that were maintained on lowprotein diets for 10 to 12 generations and subsequently rehabilitated in utero overgrew by 18.6% compared to those whose diet was normalised at birth (Stewart et al, 1980). In contrast, when the rat's diet was returned to meet the protein requirements at 4 weeks of age, they failed to demonstrate any recovery from effective refeeding, further highlighting the importance of a balanced maternal diet.…”

Breakfast consumption in Spanish children and young people

“…Thus, feeding rats a protein deficient diet over twelve generations resulted in progressively greater fetal growth retardation over the generations; following refeeding with a normal diet it then took three generations to normalize growth and development 60 . Strong evidence for major intergenerational effects in humans has come from studies showing that a woman's birthweight influences the birthweight of her offspring 61 .…”