Oxygen consumption and nitrogen excretion
The effect of the type of diet on oxygen consumption was measured in individuals from each experimental diet. Oxygen consumption (VO2) was measured using a continuous flow respirometer where respirometric chambers were connected to a well-aerated re-circulating seawater system (Rosas et al., 2008). Juveniles were placed in 90-mL chambers with an approximate flow rate of 0.1 L min− 1. All animals were allowed to acclimatize to the chambers for 1–1.5 h before measurements were made. Animals were offered a Melongena corona bispinosa shell as a shelter. A chamber without an octopus (with a shelter) was used as a control both during routine metabolism and feeding metabolism measurements. To do that, the control chamber was fed with a similar ration used to feed each octopus. Measurements of dissolved oxygen (DO) were recorded for each chamber (entrance and exit) every minute using oxygen sensors attached to flow-cells that were connected by optical fibre to an Oxy 10 mini-amplifier (PreSens©, Germany). The sensors were calibrated for each experimental temperature using saturated seawater (100% DO) and a 5% sodium sulphate solution (0% DO). Fasting metabolism was obtained from measurements taken every minute for 60 min after the conditioning period. Afterwards, octopuses were fed, taking into consideration that half of the ration (15% ww day− 1) was given two times a day to complete a total ration of 30% ww day− 1. Oxygen consumption measurements during the feeding phase were taken every minute until the oxygen consumption returned to pre-feeding values. At the end of the experiment, octopuses were weighed. Oxygen consumption was calculated as the difference in dissolved oxygen concentrations between the input and output of each chamber, with the water flow being timed. Routine metabolism (Rrout) was estimated from the VO2 (mg g− 1 ww h− 1) of fasting octopuses. The apparent heat increase (RAHI; J g− 1 h− 1) was estimated from the difference between the VO2 of fasting octopuses and the maximum value attained after feeding, taking into account the time needed to reach the oxygen consumption peak after feeding.
Partial energy budget was estimated using the following equation (Lucas, 1993):
Oxygen consumption and nitrogen excretion
The effect of the type of diet on oxygen consumption was measured in individuals from each experimental diet. Oxygen consumption (VO2) was measured using a continuous flow respirometer where respirometric chambers were connected to a well-aerated re-circulating seawater system (Rosas et al., 2008). Juveniles were placed in 90-mL chambers with an approximate flow rate of 0.1 L min− 1. All animals were allowed to acclimatize to the chambers for 1–1.5 h before measurements were made. Animals were offered a Melongena corona bispinosa shell as a shelter. A chamber without an octopus (with a shelter) was used as a control both during routine metabolism and feeding metabolism measurements. To do that, the control chamber was fed with a similar ration used to feed each octopus. Measurements of dissolved oxygen (DO) were recorded for each chamber (entrance and exit) every minute using oxygen sensors attached to flow-cells that were connected by optical fibre to an Oxy 10 mini-amplifier (PreSens©, Germany). The sensors were calibrated for each experimental temperature using saturated seawater (100% DO) and a 5% sodium sulphate solution (0% DO). Fasting metabolism was obtained from measurements taken every minute for 60 min after the conditioning period. Afterwards, octopuses were fed, taking into consideration that half of the ration (15% ww day− 1) was given two times a day to complete a total ration of 30% ww day− 1. Oxygen consumption measurements during the feeding phase were taken every minute until the oxygen consumption returned to pre-feeding values. At the end of the experiment, octopuses were weighed. Oxygen consumption was calculated as the difference in dissolved oxygen concentrations between the input and output of each chamber, with the water flow being timed. Routine metabolism (Rrout) was estimated from the VO2 (mg g− 1 ww h− 1) of fasting octopuses. The apparent heat increase (RAHI; J g− 1 h− 1) was estimated from the difference between the VO2 of fasting octopuses and the maximum value attained after feeding, taking into account the time needed to reach the oxygen consumption peak after feeding.
Partial energy budget was estimated using the following equation (Lucas, 1993):
การแปล กรุณารอสักครู่..
