This thesis examines protein metabolism and growth in decapod crustaceans; protein synthesis being investigated by a flooding dose of tritiated phenylaline. Using three isoproteic diets, the effect of dietary protein on protein synthesis and growth of juvenile shrimps <I>Penaeus vannamei</I> was investigated. Survival, specific growth, and protein synthesis rates were higher (and protein degradation was lower) in shrimps fed a fish/squid/shrimp meal diet, or a 50% laboratory diet/ 50% soybean meal variant diet, than in those fed a casein-based diet. The efficiency of whole body protein retention was 94% for shrimps fed the fish meal diet suggesting that crustaceans have a low protein turnover and a high protein growth efficiency. These data suggest lower costs and consistent availability of soybean meal provides an attractive alternative to a more expensive, fish protein based, feed. However protein retention was only 80% for those fed the casein diet, the amino acid profile of which was poorly correlated with that of the shrimps. The effects of low and high rations on food consumption and protein synthesis in crabs (<I>Carcinus maenas</I>) fed either mussels or salmon were examined. With the mussel diet, the daily variability in the amount of food obtained by individuals decreased as the quantity of food provided to the group was increased. The opposite occurred for the salmon diet; i.e. the diet with the enriched protein source. Thus the nutritional status of the diet influenced appetite. The effect of feeding frequency on growth and protein metabolism in the European lobster, <I>Hommarus gammarus</I>, was investigated. A feeding regime comprising of a single daily ration of 10% of body weight, of an artificial diet, resulted in optimal growth. This was found to be the result of decreased protein degradation, rather than increased protein synthesis. The results suggest that lobsters are slow, periodic feeders and that growth can be readily increased by manipulation of particular environmental factors such as feeding frequency, space and photoperiod.
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:593106 |
| Date | January 1999 |
| Creators | Mente, E. K. |
| Publisher | University of Aberdeen |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
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