The objective of the present study was to evaluate the effect of biofloc system (BFT) and the carotenoid suplementation in the zootechnical performance and skin pigmentation of goldfish (Carassius auratus). For this purpose, the effects of two production systems (clear water and BFT) and two diets (with and without astaxanthin supplementation) were evaluated in a completely randomized 2X2 factorial design.
Goldfish juveniles (12.18±0.27 g) were divided into 24 experimental aquariums (15 L). Fish were fed twice a day (2% of body weight per day) with isoproteic (40 %) and isoenergetic (4250kcal.kg-1) diets for 56 days. Asthaxanthin was used as a carotenoid source (80 mg.kg-1). At the end of the experiment zootechnical performance indexes and pigment intensity (portable colorimeter) of the skin were evaluated.
There was no interaction between the systems and the diets (P>0.05) for any of the performance or skin pigmentation variables. No effect (P>0.05) on goldfish performance was observed (Table I). The cultivation in BFT system improved (P<0,05) the pigmentation of goldfish skin in relation to the clear water system (Table II). Carotenoid supplementation intensified fish pigmentation regardless of the culture system used.
Cultivation in the BFT system improves the goldfish skin pigmentation when compared to the clear water system. These results prove that the BFT system is an effective and promising technology for goldfish production. The BFT system promotes pigmentation but it can be intensified with exogenous sources.