Microminerals are essential nutrients required for normal metabolism, of which iron is one involved in several biochemical processes, such as oxygen transport, electron transfer, and energy metabolism. The application of mineral nanoparticles has been gaining traction in animal nutrition due to their increased surface area which may enhance bioavailability, thereby improving micronutrient uptake. Idiopathic catfish anemia is an ongoing disease first reported in 1983, and catfish producers have provided iron-supplemented feeds to mitigate this disease. The present study evaluated the supplementation of iron nanoparticles and the organic acid (calcium propionate) on channel catfish growth performance, blood chemistry, and health parameters. A feeding trial was carried out for 9 weeks to evaluate two factors, the source of iron (bulk and nanoparticles) and the supplementation of organic acid (with and without calcium propionate). The iron was included at 1000 mg/kg of feed and the calcium propionate at 0.25% of dry weight. The growth performance, hematological parameters, and viscerosomatic indices have been analyzed. The organic acid decreased the weight gain of fish independent of the iron source (Figure 1A). An interaction was observed, where RBC decreased significantly when the nano iron was combined with the calcium propionate (Figure 1B). Significant differences also were observed in hematocrit between fish fed the bulk iron (43.7 ± 3.6%) and nano iron (40.6 ± 2.3%) (Figure 1C).
Overall, iron in bulk form and iron nanoparticles affected the blood hematocrit. However, dietary calcium propionate negatively affects the weight gain and RBC of channel catfish. Samples from the intestinal microbiota, the whole-body proximate composition, and the immune parameters of the plasma are currently being analyzed and will be presented.