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Int.J.Biosci Table 2. Range of physico-chemical water quality parameters in the nursery tank over a 30-day rearing period of whiteleg shrimp post-larvae.ParameterWater Temperature (°C)Salinity (ppt)pHDissolved Oxygen (ppm)Anunonia-N (ppm)Nitrite-N (ppm)Nitrate-N (ppm) Though it is generally believed that the supply of feedand organic inputs in tanks increase organic mattercontent, which in turn favor the growth of Vibrios(Ferreira et al., 2011), the results in our present studyproved otherwise: the Vibrio population in thenursery tank was kept in check due to the presence ofbioflocs. In shrimp culture, the Vibrio populations areregularly monitored because under certain conditions they can be harmful to shrimp, resulting in either Range27 - 3218 - 247.9 - 8.75.0 - 8.00-1.00 -0.3Not detected excessive mortality or significant reduction in growth(Aguirre-Guzman et al., 2004). Earlier studies inshrimp biofloc systems showed that Vibrios aresignificantly reduced and disease resistance of theshrimp is enhanced in the presence of bioflocs (Crabet al., 2010; Aguilera-Rivera et al., 2019; Sajali et al.,2019) resulting in lower incidences of vibriosis and mortality (Cardona et al., 2015; Anand et al., 2017; Lee et al., 2017). Fig. 1. A 450 m2 circular tank with plastic liner installed for the nursery production of whiteleg shrimp. Photo by
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