Nannochloropsis spp. as Feed Additive for the Pacific White Shrimp: Effect on Midgut Microbiology, Thermal Shock Resistance and Immunology

<p>This work aimed to evaluate Nannochloropsis spp. as feed additive in the diet of Pacific<br> white shrimp for their effect on midgut microbiology, thermal shock resistance and immunological<br> parameters. Initially, the digestibility of the microalgae meal was assessed, and the apparent<br> digestibility coefficient (ADC) was determined. The ADC was, in general, high in lipids (78.88%)<br> and eicosapentaenoic fatty acid (73.86%). Then, Nannochloropsis spp. were included in diets at four<br> levels (0, 0.5, 1 and 2% inclusion). The shrimp were reared in 500 L clear water tanks containing 20<br> shrimp per tank with an initial weight of 6.05 &plusmn; 0.06 g and fed four times a day. Shrimp fed with<br> supplemented diets containing Nannochloropsis spp. (0.5 and 2%) presented higher resistance to<br> thermal shock when compared to the non-supplemented group (control). Shrimp fed with 1 and 2%<br> of algae inclusion had a higher production of reactive oxygen species (ROS) when compared to<br> other treatments. No statistical difference was observed in the immunological parameters and<br> microbiology of the intestinal tract. Thus, the inclusion of Nannochloropsis spp. in shrimp diets at 0.5<br> and 2% levels increases resistance to thermal shock and ROS production in shrimp.</p>