Growth, biochemical and physiological responses of Salminus brasiliensis with different stocking densities and handling

Growth and stress of dourado cultivated in cages at different stocking densities

“…indicate that the experimental condition stressed fish since hyperglycemia contributes to supply the energy demand (Braun et al, 2010), in this case, through the activation of glycogenolysis/glycogenesis, inhibition of glycolysis, and the increase of hepatic glycogenesis, processes that result in glucose production (Montero et al, 1999). The temporal increase of plasma lactate confirms the presence of stress (Figure 1 B).…”

“…The feed conversion rates in fish reared in laboratory ranged from 1.5 to 2.0 (Braun et al, 2010), and in cages from 2.5 to 5.0 (Beux et al, 2008), a result that was dependent on the handling intervals associated with the stocking densities. The feed conversion rate obtained in the density of 30 fish per square meter was similar to that recorded by Beux et al (2008) when cultivating dourado in the same density, with handling intervals of 60 days.…”

“…Density can also affect growth rates and may cause changes in the metabolism of fish due to the increase of stress levels (Braun et al, 2010). Stress can become chronic, leading to a decrease in productivity, and can cause fatal outbreaks (Montero et al, 1999).…”

Stocking density during the initial grow-out phase of tambatinga in net pens

“…Glucose is a primary source of energy in fish, and an increase in glucose levels in the blood occurs as a secondary response to stress (BRAUN et al, 2010). Similarly, increase in erythrocyte concentration is related to a greater oxygen demand in stress conditions (BRAUN et al, 2010), whereas variation in total plasma protein is an indicator of osmotic imbalance (WEDEMEYER, 1996). The values for glucose, hematocrit, and plasma proteins obtained for tambatinga were similar to those for tambaqui (BRANDÃO et al, 2004;CHAGAS et al, 2005;2007).…”

“…Assessment of physiological indicators of stress is an important tool to understand adaptation processes in fish (GOMES et al, 2006). Glucose is a primary source of energy in fish, and an increase in glucose levels in the blood occurs as a secondary response to stress (BRAUN et al, 2010). Similarly, increase in erythrocyte concentration is related to a greater oxygen demand in stress conditions (BRAUN et al, 2010), whereas variation in total plasma protein is an indicator of osmotic imbalance (WEDEMEYER, 1996).…”