Ventilatory flow relative to intrabuccal and intraopercular volumes in the serrasalmid fish Piaractus mesopotamicus during normoxia and exposed to graded hypoxia

Abstract

Ventilation volume Vg - mlH2O.min-1 ), respiratory frequency (fR - breaths.min-1) and tidal volume (VT - mlH2O.breath-1 ) were measured in a group of Piaractus mesopotamicus (650.4 +/- 204.7 g; n = 10) during normoxia and in response to graded hypoxia. The fR was maintained constant, around 100 breaths.min-1, from normoxia until the O2 tension of the inspired water (PiO2) of 53 mmHg, below which it increased progressively, reaching maximum values (157.6 +/- 6.3 breaths.min-1) at 10 mmHg. The VT rose from 1.8 +/- 0.1 to 6.0 +/- 0.5 and 5.7 +/- 0.4 mlH2O. breath-1 in the PiO2 of 16 and 10 mmHg, respectively. The Vg increased from 169.3 11.0 (normoxia) to 940.1 +/- 85.6 mlH2O. min-1 at the PiO2 of 16 mmHg, below which it also tended to decrease. A second group of fish (29 to 1510.0 g, n = 34) was used for the evaluation of allometric relationships concerning ventilation and dimensions of the buccal and opercular cavities. At maximum Vg, the VT corresponded to 93.2 +/- 2.4% of the buccal volume and 94.9 2.3% of the opercular volume, suggesting that the Vg of P. mesopotamicus is limited by the volumes of buccal and opercular cavities in severe hypoxia.

Phenotypic plasticity associated to environmental hypoxia in the neotropical serrasalmid Piaractus mesopotamicus (Holmberg, 1887) (Characiformes: Serrasalmidae)

“…The increase in respiratory frequency and tidal volume is a widely used strategy to improve oxygen uptake during hypoxia for many fishes, but the relative importance of the two processes differ among species Florindo et al, 2006). In P. mesopotamicus gill hyperventilation is achieved mainly by augmenting the tidal volume, which is an energetically more efficient strategy than the increment in ventilatory frequency (Kalinin et al, 2000). The plastic development of opercular valve could represent an adaptation to improve the performance of this strategy.…”

“…In this study, we used the characiform fish Piaractus mesopotamicus (Holmberg, 1887), a species typical of frequently hypoxic floodplain environments of South America, which exhibit a series of morphological and physiological adaptations to survive at low DO concentrations (Rantin et al, 1998;Saint-Paul & Bernardinho, 1988;Severi et al, 1997;Kalinin et al, 2000;Leite et al, 2007). In a series of laboratory experiments we studied comparatively behavioral, morphological, and respiratory responses of P. mesopotamicus along a gradient of DO concentrations.…”

Cardiorespiratory physiological phenotypic plasticity in developing air‐breathing anabantid fishes ( Betta splendens and Trichopodus trichopterus )

“…Although these two values cover a fairly wide range of opercular rates, they fall within the wide range of values for larvae of other aquatic freshwater teleost fishes at similar temperatures or when corrected for different temperatures using a Q10 of 2e.g., (Burggren et al 2016;Holeton 1971;Lerner et al 2007;Vosyliene et al 2005). These gill ventilation rates of larvae are considerably higher than ventilation rates in the much larger adults of the same species of either strictly aquatic or air breathing fishesfor example, (Cerezo et al 2006;Kalinin et al 2000;McKenzie et al 2007;Porteus et al 2011;Richards and Haswell 2011), as would be expected from scaling effects on physiological processes.…”

Effects of water viscosity upon ventilation and metabolism of a flatfish, the common sole Solea solea (L.)

“…Accordingly, we found that smaller individuals exhibited a higher yield stress than larger ones. As fish grow, the distance between secondary lamellae increases (Hughes 1984), as does the total volume of their buccal and opercular cavity (Kalinin et al 2000). Thus, the volume available to water flow is larger in larger fish and the mean water velocity in the free stream is potentially higher.…”