In vitro digestibility of oils used in feed for Macrobrachium tenellum, Macrobrachium americanum and Litopenaeus vannamei adults

The objective of this work was to determine in vitro digestibility of some used or potentially used oils in feed for adult organisms of Macrobrachium tenellum, M. americanum, and Litopenaeus vannamei. For this purpose different feed oils were assessed, eight animal oils (shark liver, fish, sardine, salmon, tuna orbit, red crab, cod liver, and krill); 12 vegetable oils (chia, soya, macadamia, corn, sesame, safflower, coconut, wheat germ, olive, peanut, pumpkin seed, and canola); and two feed grade triglycerides (tripalmitin and tributyrin). In the in vitro digestibility analyses of these feed oils, the digestive enzymes of the three species in study were used with the pH Slat method. The digestion speed results were analyzed according to origin (animal, vegetable), types of oils (crustacean, fish, gramineae, leguminosae, and other types of vegetables), and ingredients for each species and among them. The three crustacean species assessed have the capability of hydrolyzing oils with heterogeneous fatty acids indicating the presence of triacylglycerol lipases in their hepatopancreas for lipid digestion. The fastest digestion speed for the studied species was observed in crustacean oils, possibly due to the balance between the proportion of their saturated and unsaturated fatty acids, which was 1:1.4. Likewise, high values of tributyrinase were found in these organisms, suggesting an important role of this activity as part of their lipolytic capacity and reinforcing the idea of true lipase participation in triglyceride hydrolysis with both short and long chain fatty acids. This information allows knowing the level of maximum digestion and potential use of oils in feed formulation for these species. Hence, this study can be the basis for more research on ingredients, fatty acid profiles, in vivo digestibility, and their effects on the productive parameters of the organisms under rearing conditions.