| Summary: | This study evaluated the use of <i>Ulva ohnoi</i> as an ingredient in feeds for aquaculture in three different experiments. Experiment 1 was oriented to confirm the negative effect of <i>U. ohnoi</i> on fish digestion. Experiment 2 assessed the effect on growth, feed efficiency, and immune status of juvenile sea bass (<i>Dicentrarchus labrax</i>) fed on diets including <i>U. ohnoi</i>, previously treated or not with carbohydrases used to partially hydrolyze indigestible polysaccharides. Experiment 3 was aimed to evaluate the potential protective effect of <i>U. ohnoi</i> on the oxidative status of sea bream (<i>Sparus aurata</i>) challenged by the consumption of a feed formulated with the oil fraction completely oxidized. Results show a negligible effect of <i>U. ohnoi</i> meal on protein digestion when included in feeds at levels of 10% or less. Moreover, results of growth and feed use evidenced the possibility of using up to 5% inclusion of algal meal in feeds without adverse effects on the zootechnical parameters, while the enzyme pretreatment was ineffective to improve its nutritional use. Finally, the inclusion of <i>U. onhoi</i> in feeds determined both an immunostimulatory effect, evidenced by an increase in skin mucus lysozyme in the two mentioned fish species, and a positive influence on the oxidative metabolism of seabream when fed on a diet including rancid oil.
|
|---|
