Inclusion of lupin meal and effect of a commercial feed supplement (Synergen™) in diets for carp, Cyprinus carpio

Plant proteins are mainly used to formulate diets for carp. Soybean meal (SBM) is one of the most nutritious of all plant protein sources in carp feeds. However, an increase in the use of soybean meal for human consumption and animal feed in both developed and developing countries has resulted in an increase market price of soybean meal globally. Therefore, using other inexpensive plant protein sources in carp feeds would be beneficial to reduce feed cost and contribute to food security as well as to sustain aquaculture production. Anti-nutritional factors (ANFs) are believed to be the most important factors limiting the use of plant protein concentrates in fish feeds. To address this limitation, one option is to use an exogenous (mixedenzyme containing, solid state fermentation, SSF) dietary supplement. Two nutritional trials were conducted in order to assess the incorporation of extruded white lupin (Lupinus albus) and supplement SynergenTM in diets for juvenile carp. The first trial was designed to determine the effect of including 12.5% and 25% of white lupin as a soybean meal replacement with the addition of 0.05% of SynergenTM for common carp BSD (Basal skretting diet) based diet on growth performance, feed utilization and general health of the fish. All diets were formulated based on the summit dilution trial type. Supplementing SynergenTM to the BSD based diet and the diet including 12.5% of white lupin significantly (P<0.05) improved growth performance and feed utilization but this trend was very slight with the diet that contained 25% of white lupin. On the other hand, including 12.5% of white lupin significantly (P<0.05) improved growth performance and feed utilization. On contrary, including 12.5% of white lupin IV significantly (P<0.05) decreased growth performance and feed utilization. No significant (P>0.05) differences were found in growth performance, carcass composition or liver and gut histology between the BSD based diet and diet that contained 25% of white lupin with SynergenTM. The second trial was designed to determine the effects of substituting 12.5% and 25% of the soya protein concentrate (SPC) with white lupin seed meal and with the addition of 0.1% of SynergenTM for the mirror carp (Cyprinus carpio) plant based diet on growth performance, feed utilization and general health of the fish. All diets were formulated to be iso-nitrogenous (38% crude protein) and isolipdic (8% crude lipid). Supplementing SynergenTM to the soya protein concentrate based diet and the diets substituting 12.5% and 25% of soya protein concentrate with white lupin significantly improved growth performance, feed utilization and gut and liver histology. Additionally, substituting up to 25% of soya protein concentrate with white lupin in the complete diet for mirror carp did not have any significant negative effects on growth performance, feed utilization, carcass composition and fish health. The results of this research program demonstrate that supplementing SynergenTM to plant based diets is beneficial to reduce the negative effect of anti-nutritional factors and to improve growth performance and nutrient utilization for carp. In addition, our findings demonstrate that lupin meal has a promising potential for use in common carp and mirror carp feeds with importance for the aquaculture industry.