Effects of Feeding and Starvation

1 Short-Term Response The Post-Prandial Anabolic Surge 

When rainbow trout have been denied food for 6 days, meals bring about a post-prandial surge in protein synthesis in all the tissues (McMillan and Houlihan 1988). The time course of the protein synthesis response appears to be tissue-specific. Tissue protein synthesis rates in the ventricle and red and white muscle exhibited a graded response where a single meal resulted in synthesis rates lying between the fasted and continually fed states. The gill, stomach and intestine responded with a rapid rise within 3 h to the levels found in continually fed fish and this stimulation was maintained. The liver demonstrated a transient increase in protein synthesis which reached a peak at 3 h, which subsequently declined. Subsequent analysis has revealed that the peak found in the liver occurred within 1 h of the meal (McMillan and Houlihan 1989). A stimulation of muscle protein synthesis has been found in salmon 9 h after feeding (Fauconneau et al. 1989). 

Following a meal, oxygen consumption takes 2 to 6 h to reach a maximum level in many species of fish (Pandian 1987). If this is true of trout, the post-prandial stimulation in the rates of protein synthesis in the skeletal muscle could not be responsible for the rapid rise in oxygen consumption. Rather, the liver is much more likely to be responsible for the initial rise in oxygen consumption. 

The oxygen consumption of the crab Carcinus increased twofold at 3 h after the meal and returned to its previous value within 24 h. The whole body protein synthesis rates of animals fed similarly sized meals paralleled the oxygen consumption changes protein synthesis rates increased twofold by 3 h after the meal and remained elevated for 16 h (Fig. 5). 

Thus far, these results indicate that there are post-prandial surges in protein synthesis, with different tissues responding to the meal at different times. The whole body protein synthesis rates rise and fall after a meal with a pattern similar to the post-prandial increases in oxygen consumption. The whole body response to a meal appears to be an amalgam of the individual tissues which are responding to the meal with differing time courses. 

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Cook, C. B., MuUerparker, G., and D Elia, C. F. (1992). Ammonium enhancement of dark carbon fixation and nitrogen limitation in symbiotic zooxantheUae—Effects of feeding and starvation of the sea-anemone aiptasia-paUida. Limnol. Oceanogr. 37(1), 131—139. 

Yamano, T., Yorita, K., Fujii, H. et al (1988). Gluconeogenesis in perfused chicken kidney effects of feeding and starvation. Comp. Biochem. Physiol, 91B, 701-6. 

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