Effects of background colour on growth performance, skin pigmentation, physiological condition and innate immune responses of goldfish,Carassius auratus

Abstract

A study was carried out to investigate the effects of background colour on the growth performance, skin colour, haematology, physiological condition and non‐specific immune responses of goldfish, Carassius auratus. Goldfish were reared in tanks with four different background colours (white, black, blue and red) for 8 weeks. Fish growth performance markedly rose in white background compared with the other treatments. There was no significant difference in haematological parameters or plasma proteins concentrations between treatments. Plasma cortisol of fish reared in red background was significantly higher than that in black and white backgrounds. Plasma antiprotease and lysozyme activities were more than doubled in white and black treatments compared with the red and blue groups. The other immune parameters tested (plasma peroxidase, complement and bactericidal activities) did not significantly change between treatments. Skin carotenoid content and the intensity of fish skin colour extremely diminished in white background. This study revealed that red and blue backgrounds are chronically stressful and immunosuppressive in goldfish. White backgrounds will preferably be used for the culture of goldfish for best fish growth. However, a way to revert the colour loss of goldfish skin reared in white backgrounds remains to be investigated.

The effect of environmental colour on the growth, metabolism, physiology and skin pigmentation of the carnivorous freshwater catfish Lophiosilurus alexandri

“…In L . alexandri juveniles, the different environmental colours did not alter the plasma protein, triglyceride and cholesterol levels, similar to that which was also recorded for C. carpio (Papoutsoglou et al ., ), Huso huso L. 1758 (Banan et al ., ) and Carassius auratus (L. 1758) (Eslamloo et al ., ) reared in different colour tanks. In contrast, the haematocrit level did vary and was greatest for fish kept in white tanks.…”

“…alexandri juveniles from the white and yellow tanks had a paler skin colour. Pale skin in farmed fish from white tanks is consistent with what has been reported during the cultivation of Melanotaenia australis (Castelnau 1875) (Rodgers et al ., ), C. auratus (Eslamloo et al ., ), Amphiprion ocellaris Cuvier 1830 (Yasir & Qin, ) and O. niloticus (Opiyo et al ., ).…”

The impaired intestinal mucosal immune system by valine deficiency for young grass carp (Ctenopharyngodon idella) is associated with decreasing immune status and regulating tight junction proteins transcript abundance in the intestine

“…Water temperature and pH were 26 ± 2 C and 7.0 ± 0.5, respectively. The fish were fed with the respective diets four times daily for 8 weeks, according to Eslamloo et al [36]. Thirty minutes after feeding, uneaten feed was collected, dried, and weighed to calculate the feed intake, as described by Mundheim et al [37].…”

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“…Papoutsoglou, Mylonakis, Miliou, Karakatsouli, and Chadio (2000) reported that fish reared in black tanks had significantly higher plasma cortisol levels than those reared in white tanks, and specific growth rate and final weight was significantly higher and feed conversion ratio significantly lower in white tanks. This was also observed by Eslamloo, Akhavan, Eslamifar, and Henry (2015), Rahnama, Heydarnejad, and Parto (2015), Wang et al (2016), and Wang et al (2017). On the contrary, Downing and Litvak (2000) and MartinRobichaud and Peterson (1998) found larvae reared in dark coloured tanks to show lower stress levels, higher food intake, and less body damage.…”