The Growth and Energy Allocation of the Brown Flounder,Paralichthys Olivaceus During Thermal Manipulation
HUANG Guo-Qiang,WEI Liu-Zhi,ZHANG Xiu-Mei,ZHANG Pei-Dong(College of Fisheries,Ocean University of China,Qingdao 266003,China)
An experiment was conducted to investigate the growth and energy allocation of juvenile brown flounder,Paralichthys olivaceus during thermal manipulation.During the stress period,the 17.5 ℃ acclimated juvenile brown flounder were cultured at 8.5 ℃(T8.5),13.0 ℃(T13.0),17.5 ℃(T17.5),22.0 ℃(T22.0),and 26.5 ℃(T26.5) for 10 d.At the end of the stress period,the fish in T22.0were larger than the other treatments in wet mass,dry mass,protein,and energy content,and except for dry mass,were not significantly different from those in T17.5 and T26.5.The temperature induced growth differences were completely compensated in 30 d after the temperatures were adjusted to 22.0 ℃.Through the stress period,less feed ingestion and a smaller fraction of energy allocated to growth mainly depressed the growth of fish at low temperatures(T8.5 and T13.0),whereas a smaller fraction of energy allocated to growth accounted for the slow growth in T17.5and T26.5.When the fish was kept at low temperature,the energy lost in feces and respiration decreased the energy allocated to growth.Whereas it was the higher proportion of excretion energy that caused less energy being allocated to growth for fish kept at high temperature.During the second 10 d period after temperature adjusting,fish in T8.5,T13.0,T17.5,and T26.5 ingested more feed than T22.0.But no significant difference in ingestion was observed for the whole period after temperature adjusting and the energy allocations among growth,feces,excretion,and respiration show no treatment specific difference.Hence it was concluded that compensatory growth was achieved mainly by short-term increaes in feed intake(hyperphagia).For the whole period after temperature adjusting,the daily unit body weight energy ingestion and growth in T8.5,T13.0,T17.5,and T26.5were significantly higher than in T22.0.Thus the fish exhibited compensatory growth.Through the whole experimental period,fish in T8.5 ingested less feed than in the other treatments.But they allocated more energy to growth than the other treatments because they lost less energy in excretion and respiration.Different temperature experiencing changed the protein and energy content of juvenile brown flounder and the energy content of fish in T8.5 and T26.5 were still significantly different from those in T22.0.The above results indicated that juvenile brown flounder show flexibility to temperature changes and short-term temperature change would not impact their long-term growth.
【Fund】： 国家自然科学基金项目(30600462);; 国家支撑计划课题(2006037029019);; 中国水产科学院渔业环境与养殖生态重点实验室开放课题资助
【CateGory Index】： S917.4
【CateGory Index】： S917.4