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Combined effect of temperature, salinity and density on the growth and feed utilization of Nile tilapia juveniles ( Oreochromis niloticus )
Author(s) -
Jun Qiang,
Pao Xu,
Haizhen Wang,
Ruiwei Li,
Hui Wang
Publication year - 2012
Publication title -
aquaculture research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.646
H-Index - 89
eISSN - 1365-2109
pISSN - 1355-557X
DOI - 10.1111/j.1365-2109.2011.02938.x
Subject(s) - salinity , nile tilapia , oreochromis , biology , zoology , temperature salinity diagrams , growth rate , box–behnken design , tilapia , feed conversion ratio , aquaculture , fishery , fish <actinopterygii> , response surface methodology , ecology , mathematics , statistics , body weight , geometry , endocrinology
Based on Box–Behnken experimental design and response surface method, the joint effect of temperature (16–36°C), salinity (0–22 ppt) and rearing density (200–1000 fish.m −3 ) on the specific growth rate ( SGR ) and feed conversion rate ( FCR ) of Nile tilapia juveniles were studied under laboratory conditions. The entire experiment lasted for 1 month (30 days). Results showed that the linear and quadratic effects of temperature, salinity on both growth and feed utilization were highly statistically significant ( P < 0.01). The linear and quadratic effect of rearing density on the growth was highly significant ( P < 0.01); the linear effect of rearing density on feed utilization was significant ( P < 0.05), but the quadratic effect nonsignificant ( P > 0.05). Interactions between temperature and salinity, and between salinity and rearing density on the growth statistically differed from zero ( P < 0.05). Interactions between temperature and salinity, between temperature and density on feed utilization was significant ( P < 0.05). Model equations of the growth and feed utilization on temperature, salinity and density were established, with the coefficient of determination being 98.34% for growth and 98.11% for feed utilization, and could be applied to projection. The optimal temperature/salinity/density combination was obtained utilizing statistical optimization approach: 29°C/6 ppt/500 fish.m −3 , at which the maximal specific growth and feed utilization reached 4.228%.d −1 and 0.520 respectively, with the desirability being 0.989.