| The study was designed to determine the differences of different feeding technology on feeding, growth, digestion and energy budget of Portunus trituberculatus. The results of these studies are listed below.1 Study on feeding parameters of crabs(Portunus trituberculatus) ofⅣinstar-ⅥinstarThe parameters of circadian feeding rhythm, feeding rate and food consumption in day and night ofⅣinstar,Ⅴinstar andⅥinstar juvenile Portunus trituberculatus were investigated. There was a pronounced feeding peak. Feeding peak ofⅣinstar crabs occurred at about 20:00-23:00 and 2:00-5:00,Ⅴinstar crabs occurred at about 20:00-23:00 and 5:00-8:00, andⅥinstar crabs occurred at about 17:00-20:00 and 5:00-8:00. The crabs of different developmental stages had different feeding peaks. There were two small peaks on each stage of the crabs and feeding time intervals extended.2 Differences of food consumption, metabolism and growth of the crabs (Portunus trituberculatus) fed fresh, frozen and oven-dried clam(Ruditapes philippinarum) meatThe experiment was conducted to investigate the effects of fresh, frozen and oven-dried clam meat (three groups) on food consumption, metabolism and growth of the crabs with the wet weight of 10.14g±0.53g. Daily feeding rates of the oven-dried clam meat group was the highest (P<0.05). Specific growth rates (SGRdw) of the fresh clam group was highest (P<0.05). There were significant differences about food conversion efficiencies (FCEdw) among the three groups (P<0.05). Nitrite nitrogen excretion rates of the fresh clam meat group during 0～2 and 2～4 hours after satiation were significantly higher than those of frozen group and oven-dried group (P<0.05). No differences were found among these groups during 4～6 hours. In respect of ammonia nitrogen excretion and oxygen consumption rate, significant differences were found among the three groups (P<0.05), and the high-to-low order was the frozen clam, oven-dried clam and fresh clam meat group. Moreover, the crabs of the fresh clam group had the highest SGRdw, FCEdw compared with the frozen clam and oven-dried clam meat group. Conclusively, in the situation of appropriate feeding, it is not only good for increasing production, but also good for cleaning production when feeding the crab fresh clam meat.3 The differences of blood sugar levels of satiation when the swimming crabs were fed with oven-dried and fresh clam clamThe experiment determined changes of blood sugar levels of satiation when the swimming crabs were fed with oven-dried and fresh clam clam. The results showed that blood sugar content of the crabs on a 48-hour fast were 0.415mmol/l±0.023mmol/l and there were no significant differences about the threshold of hemolymph glucose levels oven-dried and fresh clam clam group crabs after satiation. It was suggested that when the blood sugar of fresh clam clam group levels reach 0.605 mmol/l±0.010 mmol/1 and oven-dried clam clam group reach 0.620 mmol/l±0.012 mmol/l, the crabs stop feeding. It reminded us that the date was the blood sugar level of crabs after satiation. The time that the oven-dried clam group crabs reaching the threshold of hemolymph glucose levels was prolonged compared with the fresh clam clam group. It reminded us that the oven-dried clam may go against digestion and absorption.4 The differences of feeding, digestion, growth and energy balance of crabs (Portunus trituberculatus) fed clam meat and squid meat alternatelyIn the study, there were four groups. They were short necked clam meat (Ruditapes philippinarum) meat group, squid (Loligo chinensis) meat group, short necked clam meat one day and squid meat two days alternately feeding group(claml+squid2), and short necked clam meat two days and squid meat one day alternately feeding group(clam2+squidl). Feeding, digestion, growth and energy budget of the crabs with the wet weight of 54.05g±3.51g of seven groups were studied. The results showed that about average daily feeding rate and the specific growth rate of crabs, the clam meat group (2.38%±0.28%,1.59%·d-1±0.18%·d-1) was significantl y higher than the squid group (1.59%±0.23%,1.07%·d-1±0.17%·d-1) (p<0.05) and there were no significant differences between (clam2+squidl) group and the clam meat. (clam1+squid2)meat group was higher than squid group and lower than clam meat group (p<0.05). About feed conversion efficiency, there were no significant differences between 4 groups. About the apparent digestibility of sugar, there were no significant difference about (clam2+squid1) group and clam group and no difference about (clams1+squid2) group and the squid meat group. Also, the squid meat group was the lowest. The apparent digestibility of protein of alternating treatment groups was significantly higher than clam and squid meat group. The apparent digestibility of ash of alternating treatment group was significantly higher than clam meat group. Daily feeding energy of alternating feeding groups was significantly higher than squid meat group and no significant difference with the clam meat group. About the proportion of the growth energy, there were no significant differences between (clam2+squid1) group and squid meat group. It can be seen that the swimming crabs grew better when feeding squid meat compared with feeding clam meat. The crabs of the two alternative feeding grew better than that of squid meat group. The growth effect of (clam2+squid1) group was similar with the clam meat group and (clam1+squid2) group was better than the clam meat group. It was suggested that feeding the crabs clam meat or alternative feeding clam and squid meat could get a better cultivation effect.5 The differences of feeding, digestion, growth, carbon balance, nitrogen balance and energy balance of crabs (Portunus trituberculatus) fed shellfish meat and fish meat alternatelyIn this study, there were 7 groups. They were blue clam(Aloidis laevis) meat group, Pacific oyster(Crasostreagigas)meat group, short necked clam (Ruditapes philippinar um) meat group, little yellow croaker(Pseudosciaena polyactis) meat group, blue clam meat and a little yellow croaker meat alternately feeding group(blue clam+fish), oysters meat and a little yellow croaker meat alternately feeding group (oyster+fish), short necked clam meat and a little yellow croaker meat alternately feeding group(short necked clam+fish). Feeding, digestion, growth, carbon balance, nitrogen balance and energy balance of payments of the crabs with the wet weight of 15.48 g±1.57g of seven groups were studied. The results were in the following:(1) The daily feeding rate of alternate feeding group was higher than fish group, and lower than the corresponding clam meat group. The main differences were (p<0.01) in the following: fish groupblue clams group(p<0.01), oyster+fish group>oyster group(p<0.01),short-necked clam+fish group>short-necked clam group (p<0.05). It can be seen that the growth of crabs fed alternately of shellfish meat and fish can reach or exceed the optimal level of the individual feeding. Alternately feeding was a better feeding strategy.
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