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Growth and energy budget of the polychaete,Neanthes japonica,at various temperatures(17,20,23,26 and 29℃) were investigated in this study. The growth,as indicated by final dry weight and specific growth rate(SGR),increased with increasing temperature,with the maximum level at 26℃,and then decreased significantly at 29℃. A similar trend was observed in feeding rate,food conversion efficiency(FCE) and apparent digestive rate(ADR). However,no significant differences were detected in ADR among all the temperature treatments. In the pattern of energy allocation,faeces energy was only a small component of energy budget and had little influence on the proportion of food energy allocated to growth. The metabolic energy accounted for a large portion of energy intake for each temperature treatment. The nitrogen excretion was appreciable with changing temperature. The two expenditure terms(respiration energy and excretion energy) in energy budget were the major factors influencing the proportion of food energy allocated to growth. These results revealed that temperature affected the growth of N. japonica mainly by influencing feeding rate and FCE. In addition,regression equations describing the relationship between feeding rate,faecal production,SGR,FCE and temperature were obtained. The optimum temperatures for feeding rate,FCE and SGR were estimated at 25.01℃,24.24℃ and 24.73 ℃,respectively,from the regression equations.
Growth and energy budget of the polychaete, Neanthes japonica, at various temperatures (17,20,23,26 and 29 ° C) were investigated in this study. The growth, as indicated by final dry weight and specific growth rate (SGR), increased with increasing temperature, with the maximum level at 26 ° C, and then decreased significantly at 29 ° C. A similar trend was observed in feeding rate, food conversion efficiency (FCE) and apparent digestive rate (ADR). However, no significant differences were detected In the pattern of energy allocation, faeces energy was only a small component of energy budget and had little influence on the proportion of food energy allocated to growth. The metabolic energy accounted for a large portion of energy intake for each temperature treatment. The nitrogen excretion was appreciable with changing temperature. The two ex-energy (respiration energy and excretion energy) in energy budget were the major factors influencing the propo rtion of food energy allocated to growth. These results reveal that temperature affected the growth of N. japonica mainly by influencing feeding rate and FCE. In addition, regression equations describing the relationship between feeding rate, faecal production, SGR, FCE and temperature were obtained . The optimum temperatures for feeding rate, FCE and SGR were estimated at 25.01 ° C, 24.24 ° C and 24.73 ° C, respectively, from the regression equations.