Hyperplasic and Hypertrophic Growth in Brain, Liver and Muscle of Undernourished Suckled Pigs

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Abstract
From 5 to 35 days of age, 32 Yorkshire pigs either remained with their dams continuously or were removed for 16 hr each day. At 35 days half of each group were slaughtered, while the remainder were weaned and fed ad libitum until slaughtered at 70 days of age. Following slaughter brain, liver and a gastrocnemius muscle were weighed in entirety and sampled for determination of DNA, RNA and protein. At 70 days total carcasses and viscera were also analyzed for nitrogen, ether extract, ash and moisture. Restricting suckling reduced growth rate by 61%. Reductions in liver and muscle weight were proportional to total body but brain weight was reduced by only 6%. Restriction had no significant effect on the DNA content (cell number) of brain but reduced DNA contents of liver and muscle by 54 and 60%, respectively. The effects on protein:DNA ratio (cell size) were very much less. During the 35-day recovery period the previously restricted pigs failed to reduce their body weight discrepancy, but there was considerable narrowing of the difference between groups in relative rates of increase in the DNA, RNA and protein contents of liver and muscle, and there were no longer any significant differences in protein: RNA ratio. The results showed that feed restriction in early life reduced cell division without affecting cell size, and that the increase in cell division during the recovery period did not result in compensatory growth. Despite the wide difference between groups in body weight, at 70 days, there were no significant differences in body composition. Copyright © 1977. American Society of Animal Science . Copyright 1977 by American Society of Animal Science.