Lupin emerges as a reliable and sustainable protein alternative for aquaculture
Scientists demonstrated that including up to 200g/kg of Andean lupin in rainbow trout diets does not affect growth or feed efficiency, positioning it as a viable protein source.
Published
Among the plant ingredients that have been studied as alternative protein sources to fish meal, some legumes of the genus Lupinus have attracted the attention of Chilean researchers.
This genus encompasses a wide range of species, estimated between 200 and 600, and some have already been successfully incorporated as ingredients for various animals, including fish.
The studies report that lupine species can be incorporated into aquaculture feeds at levels below 50% without negatively affecting growth performance and nutrient digestibility. Specifically, L. mutabilis has the highest levels of lipids and proteins of all lupine species and contains more than 45% protein and 20% lipids, being nutritionally comparable to soy.
In light of this background, scientists from the Catholic University of the North, Catholic University of Temuco, BioMar, and the University of Galway in Ireland conducted a study to evaluate different levels of inclusion of Andean lupin in rainbow trout, and determine its effect on growth, histology, and nutrient digestibility.
Promoting sustainability
By feeding the fish for 40 days with four experimental extruded diets with varying levels of Andean lupin (0, 50, 100, and 200 g/kg), the experts observed no significant correlations between the dietary inclusion of Andean lupin and the final weight of the fish, survival, weight gain, protein retention, thermal growth rate (GF3), feed conversion rate (FCR), and food intake.
Similarly, there were no significant relationships between the increased inclusion of Andean lupin and the apparent digestibility coefficients of dry matter, crude protein, carbohydrates, and energy.
However, the inclusion of Andean lupin led to a decrease in the apparent digestibility coefficients of ash. Additionally, the digestibility of Mg and Zn decreased quadratically with increasing levels of Andean lupin inclusion, as did the hepatosomatic index.
With this information, researchers proposed that Andean lupin is a reliable source of protein and can be included up to 200 g/kg in diets for rainbow trout.
“In particular, this level of inclusion does not compromise growth performance or feed utilization efficiency. These findings confirm that Andean lupin can be used as an alternative plant ingredient to reduce the load of fish meal and oil in aquaculture feeds. This, in turn, contributes to the diversification of agricultural crop production, promoting sustainability in the salmon farming industry”, the authors concluded.
However, they pointed out that it is important to expand the scope of this research through more similar studies but at various stages of the life cycle of rainbow trout and related salmonid species.
Read the full study titled "Evaluation of andean lupin (Lupinus mutabilis) seed meal as a dietary component on growth performance, feed utilization, nutrient digestibility, and liver histology of rainbow trout (Oncorhynchus mykiss) Juveniles", here.
