EFFECT OF FASTING AND REFEEDING ON GROWTH AND BODY-COMPOSITION OF REDPORGY, PAGRUS-PAGRUS L

Red porgies, Pagrus pagrus L., were fasted for 7, 14 or 28 days, and w ere then allowed to feed on pellets released from demand feeders. Biol ogical responses during fasting and refeeding were examined, The facto rs considered were growth, organosomatic indices and proximate body co mposition (protein, fat, ash and moisture). Fasted red porgies lost we ight and had higher relative weights of eviscerated body than control fish, Refeeding was accompanied by hyperphagy, which resulted in simil ar total food demand being shown by all groups. Fish which had been de prived of food displayed compensatory growth and the final weights of these fish at the end of the experiment were similar to controls, Ther e were no significant changes caused by fasting in the relative propor tion of body chemical components. Calculations based upon changes in p rotein and lipid content suggest that more protein than lipid is metab olized during the first phase (14 days) of a fast.