Influence of body weight and temperature on post-prandial oxygen consumption of common octopus (Octopus vulgaris)

Feeding periods are accompanied by increased oxygen demand, and so, water flow or oxygen supply during culture should be suitably adjusted at such times. In this study, we determine the pattern of post-prandial oxygen consumption in common octopus (Octopus vulgaris) with body weights between 0.22 and 3.26 kg, at temperatures of 13.75-22.23 °C, which covers the normal ranges of weight and temperature used for its culture. The measurements were carried out over 3 days on single animals receiving one meal of crab to satiation. The oxygen consumption values were divided into routine (MO2routine), post-prandial (MO2sda), maximum peak (MO2peak) and daily average between 0 and 24 h (MO2;0-24h), 24 and 48 h (MO2;24-48h) and 48 and 72 h (MO2;48-72h) post-feeding. Furthermore, the time taken to reach MO2peak (Dpeak) and the duration of post-prandial oxygen consumption (Dsda) were calculated. In all cases, MO2;0-24h was higher than MO2;24-48h and MO2;48-72h (P<0.05), however, in most animals, no significant differences existed between MO2;24-48h and MO2;48-72h (P>0.05). This result suggests that feeding induces a significant transient short-term effect on oxygen consumption that does not usually last longer than 24 h. The different oxygen consumption categories fitted the equations lnMO2routine=-0.726+0.702lnW+1.876lnT, lnMO2sda=0.045+0.713lnW+1.769lnT, lnMO2peak=0.152+0.716lnW+1.767lnT and lnMO2;0-24h=0.220+0.716lnP+1.688lnT to a statistically significant degree (P<0.001) with a similar weight exponent value of around 0.71. Dpeak and Dsda showed values of 6-16 h (9.98±2.49 h) and 15-28 h (19.79±3.83 h), respectively, both being independent of weight and temperature (P>0.05). Finally, the influence of other factors such as daily activity patterns or sex on oxygen consumption were analysed.