Effects of density, PVC-tubes and feeding time on growth, stress and aggression in African catfish (Clarias gariepinus)

Abstract

Successive exposure to aquaculture‐related stressors may compromise the allostatic capacity of African catfish and lead to allostatic overload and poor welfare. Therefore, we tested the effect of (i) feeding during the light or dark phase, (ii) density (51 fish per 140 L versus 51 fish per 43 L) and (iii) altered available resting space/shelter on stress handling were studied in African catfish (Clarias gariepinus). Available resting space/shelter was manipulated by providing PVC‐tubes in the tanks. Growth, baseline stress load (cortisol and osmolality), metabolism (glucose, lactate and non‐esterified fatty acids) and aggression (measured by skin scar incidence) were assessed. Upon completion of the experimental period, we determined the adaptive capacity of the fish by the response to air exposure. We show that night‐feeding enhances growth and lowers feed conversion ratio compared to day‐feeding. No effects of density were found for baseline stress hormones, basal metabolism or aggression. Low density seems to stimulate aggressive behaviour after air exposure. Unexpectedly, providing PVC‐tubes under high‐density conditions increased aggression, raised baseline cortisol levels and decreased basal metabolism as well as growth; also the endocrine response to air exposure was stronger. We argue that these effects relate to a reduction in available space, i.e. a further increase in density, or to an increased competition for shelter. Overall, our data suggest that night‐feeding optimizes growth and that care should be taken in using objects as shelter/enrichment for African catfish.

Effects of light and artificial fish shelter (PVC pipe) on some phenotypic traits of stinging catfish (Heteropneustes fossilisBloch, 1794)

“…As described above, their unique body shape could be another strong reason that evolved them to be adapted for better growth performance under dark condition. Thus, the overall finding of the present study having better growth parameters in dark condition corroborates the results obtained by some other studies (Appelbaum & Kamler, ; Boerrigter, Bos, Vis, Spanings, & Flik, ; Britz & Pienaar, ; Rahmah et al, ). In a study with C. gariepinus , Boerrigter et al () showed that night feeding enhanced growth and reduced feed conversion ratio in this species compared to day‐feeding strategy.…”

“…Thus, the overall finding of the present study having better growth parameters in dark condition corroborates the results obtained by some other studies (Appelbaum & Kamler, ; Boerrigter, Bos, Vis, Spanings, & Flik, ; Britz & Pienaar, ; Rahmah et al, ). In a study with C. gariepinus , Boerrigter et al () showed that night feeding enhanced growth and reduced feed conversion ratio in this species compared to day‐feeding strategy. Catfish prefer swimming and feeding activities under darkness which have also been supported by Rahmah et al () in their study with bagrid catfish ( M. nemurus ).…”

“…The reason of having this opposite result might be the effect of shelter competition or hiding space scarcity in the tanks. Boerrigter et al () conducted a study with C. gariepinus and found lower growth performance in fingerlings reared in high density along with shelter (PVC tubes) than in the group of fingerlings kept in low density without shelter facility. They argued about this finding as an effect of high density, which created space scarcity and competition for shelter facility.…”

Effects of acute stress on aggression and the cortisol response in the African sharptooth catfish Clarias gariepinus: differences between day and night

“…It should also be noted that, previously it has been reported that the highest levels of cortisol following stress were at 1 h post stressor exposure (van de Nieuwegiessen et al, 2008), but here, however, the highest levels were directly following the stressor. Similar observations were made after applying the same stressor (15 min forced air exposure and crowding) in another series of experiments (Boerrigter et al, 2015b) on C. gariepinus. The comparatively rapid occurrence of the peak as well as the swift recovery may have masked day and night differences in the present experiments.…”

Laboratory and field investigations on the effect of scheduled meal timings on growth performance and nutrient retention in an Indian major carp,Cirrhinus mrigala(Ham) fingerlings: Effect on nitrogen retention and excretion of metabolites

“…The existence of daily feeding rhythms with an active diurnal or nocturnal behaviour has been documented in a number of fish species (Boerrigter, van den Bos, van de Vis, Spanings & Flik, 2016;Figueiredo-Silva, Corraze, Sanchez-Gurmaches, Guti errez & Valente, 2010;Kitagawa et al, 2015;L opez-Olmeda, L opez-Garc ıa et al, 2012;Mattos, Filho, Santos et al,2016;Oliveira et al, 2013). A number of studies have demonstrated that feeding time affects growth performance, food conversion efficiency (Boerrigter et al, 2016;Bolliet, Jarry & Boujard, 2004;Caldini, Pereira, Rebouc ßas & do Carmo e S a, 2013; Guill en, Moyano & Y ufera, 2015;Kitagawa et al, 2015;Mattos, Filho, Santos et al, 2016) and even body composition (Guevara et al, 2015;Nocskc-Hallin, Spieler, Parker & Suttle, 1985). Since in the natural environment, food is hardly constantly available, and is usually restricted to a particular time when its availability is highest.…”