Growth and intestinal polyamines in tilapia (Oreochromis niloticus) and catfish (Ictalurus punctatus) fed diets with soybean oil and supplemented with probiotics

Abstract

The aims of this work were to compare the effect of four diets on intestinal polyamine levels and growth of juvenile Nile tilapia (Oreochromis niloticus, Linnaeus 1758) and channel catfish (Ictalurus punctatus, Rafinesque, 1818). The control practical diet (C diet) contained 2% fish oil and 6% soy oil. The alternative diet (S diet) contained 8% soy oil and no fish oil. The CP and SP diets correspond to the C and S diets, supplemented with a multispecies probiotic formulated for aquaculture. Biogenic polyamines putrescine (Pu), spermidine (Spd) and spermine (Spm) were determined by HPLC during a time-course feeding trial conducted for 120 days. Mean levels (nmol μL^-1) of these polyamines in the intestine of tilapia were: Pu, 0.0194 ± 0.0048; Spd, 0.0949 ± 0.0266; Spm, 0.0561 ± 0.0196 and for catfish: Pu, 0.0144 ± 0.0025; Spd, 0.1054 ± 0.0142; Spm, 0.1036 ± 0.0143. Experimental data showed that the S, CP and SP diets did not affect fish growth and polyamine levels compared to the C diet. A relationship between intestinal polyamine levels and experimental period was observed. Experimental data suggest that fish oil may be totally substituted by soy oil in the formulation of practical diets for tilapia and catfish.