Assessment of protein and phosphorus bioaccessibility of selected lupin species and varieties by simulating the gastrointestinal digestion of rainbow trout (Oncorhynchus mykiss)

MORALES, GABRIEL A.; MÁRQUEZ, LORENZO; HERNÁNDEZ, ADRIÁN J.; AZCUY, ROSENDO L.; CASARETTO, MATÍAS E.; DANTAGNAN, PATRICIO

Las Palmas de Gran Canaria

Congreso; 18th International Symposium on Fish Nutrition and Feeding; 2018

ISFNF

Legumes are considered an indispensable source of proteins and other nutrients. The interest for this type of ingredients inthe formulation of diets for aquaculture has intensified in recent years due to the accelerated growth of this industry as wellas the need to reduce the high dependence on fishmeal and fish oil. Lupin (Lupinus spp) is a large genus of leguminous plantswhich includes more than 400 recorded species, whose seeds differ considerably in their chemical composition and nutritivevalue. Different lupin species has been described as viable protein alternatives to replace both fishmeal and soybean meal in aquafeeds without significant deleterious effects on growth performance, nutrient digestibility, health condition and finalproduct quality. In addition to high protein content and a nutritional value comparable to soybean, sweet lupine varieties arecharacterized by having the lowest antinutritional content among all legumes. However, new methods of evaluation andanalysis to establish the nutritional value of the many species and varieties of lupin currently available are essential tooptimise their use in aquafeeds.An in vitro gastrointestinal model (GIM), designed to simulate the digestive conditions of fish (pH, temperature and presenceof fish digestive proteases from stomach and intestine), was used to evaluate protein and phosphorus bioavailability in sixsweet lupin varieties: Lupinus albus (Rumbo, Ramses), L. luteus (AluProt-CGNA), L. angustifolius (Lila) and L. mutabilis (Pinta,Baer). The results were contrasted with those obtained with soybean (Glycine max, SBM), considered the plant proteinreference for aquafeeds to explore their suitability for incorporation in fish diets.The bioavailability of P from each ingredient after their digestion simulating the gastrointestinal conditions of the rainbowtrout resulted in the following order of soluble P release: Baera>Pintaa>Lilaa>AluProt-CGNAab>Rumbobc>SBMbc>Ramsesc.On the other hand, protein bioavailability measured as the total amino acids released from each ingredient resulted in thefollowing order of nutrient release: Baera>Pintaa>Lilab>Rumbobc>AluProt-CGNAbc>Ramsesc> SBMd (different lettersindicate p-value