Early postnatal mammalian growth : protein and lipid synthesis as determined in vivo.
Date
1971
Authors
Davies, Peter Francis
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Abstract
The body composition of twelve piglets during early postnatal growth on two planes of nutrition was determined sequentially in vivo by isotope dilution to investigate the pattern of early mammalian growth. Animals were reared artificially from twelve hours after birth on a diet of condensed milk; six animals at a level (high plane) commensurate with rapid growth and six animals at a level of seventy percent of the high plane. At eight weeks of age, the low plane animals were realimented and the subsequent effects of growth and composition were assessed.
Phasic properties of growth and development were investigated as changes in gross body weight, protein, lipid and ash constituents of the body.
A distinct phasic pattern of early protein growth was observed and its interrelationships with phasic changes of body weight discussed. A modified mathematical treatment of growth curves and composition curves is presented and assessed. Daily synthesis of new protein was quantified on a daily basis and its efficiency estimated. Efficiencies of liveĀ weight gain were calculated. Energetic efficiencies of protein and lipid gain were assessed in relation to nutritional plane.
Fundamental control of protein synthesis appears to operate relatively independently of nutritional plane and in aphasic manner as an extension into postnatal life of phasic embryonic growth and developĀment. Control of the growth processes are briefly discussed.