Catfish play an important role in the American aquaculture, as it is the most cultured fish in the US. To farm animals with greater vigor and resistance, the feed can potentially be improved by using organic mineral premixes.
The dietary treatments consisted of the inclusion of 50% organic and inorganic mineral premix, 100% organic mineral premix, and 50% organic mineral premix + menhaden oil. The control group received the basal diet with the inclusion of 100% inorganic mineral premix. Four hundred and eighty channel catfish juveniles (Ictalurus punctatus) were equally distributed in 16 aquaria (30 fish/tank), operating as a recirculating aquaculture system and treatments were distributed in a completely randomized design. Fish were fed to apparent satiation twice a day and at the end of the feeding trial, fish were group weighed to calculate the production performance. Three fish per aquarium were anesthetized (~100 mg MS-222/L) for blood collection and hematological analyses. The remaining fish from each dietary treatment were transferred to a flow through system and acclimated for 7 days in fiberglass tanks (22 L). Fish were challenged with an LD50 of Edwardsiella ictaluri, where 70 mL of the direct BHI broth was introduced into each tank to generate a dose of 6.2×106 CFU/mL. The data were subjected to analysis of variance in one-way ANOVA, post-hoc testing was performed using the Tukey test. There was a significantly higher feed intake (56.2 g/fish) and hepatosomatic index (1.25%) for fish fed control diet (100% inorganic mineral premix). Fish fed different types of premixes did not influence resistance to E. ictaluri infection (Figure 1; P=0.10). Although nutrition plays an important role in fish health a better production performance was observed for the control group, which was formulated with 100% inorganic minerals.