Combined effect of temperature,salinity and density on the growth and feed utilization of Nile tilapia juveniles (Oreochromis niloticus) |
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Authors: | Qiang Jun Xu Pao Wang Haizhen Li Ruiwei Wang Hui |
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Affiliation: | 1. Fisheries of College of Guangdong Ocean University, , Zhanjiang, 524025 China;2. Freshwater Fisheries Research Center of Chinese Academy of Fishery Sciences, , Wuxi, 214081 China;3. Maonan Sango Tilapia Breeding Base, , Maoming, 525024, China |
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Abstract: | 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. |
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Keywords: | Oreochromis niloticus combined effect specific growth rate feed conversion rate response surface optimization |
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