The volume of feed necessary to farm whiteleg shrimp (Litopenaeus vannamei) has forced the industry to formulate feeds with increasing amounts of plant ingredients, known for lower palatability and sub-optimal nutritional profiles compared with marine ingredients. However, supplementing diets with moderate inclusions of functional ingredients, often of marine origin, can be applied to improve the overall quality of the feeds and ensure growth, health, and high feed intake. A novel raw material for aquaculture feeds and functional ingredients is the zooplankton species Calanus finmarchicus, a natural and sustainable resource harvested in the Norwegian Sea, where its annual production is estimated at 290 million tonnes. Products from C. finmarchicus include a protein powder that can be used as direct feed for larval stages, c omplete copepods for replacement of live feed in post-larval stages, and a protein hydrolysate with great potential as a functional ingredient in formulated feeds for both fish and shrimp.
Two separate trials were performed to study the effects of C. finmarchicus hydrolysate (CH) inclusion in diets for whiteleg shrimp. The first was performed by SPAROS in Portugal, with aims to document how a 4 % feed inclusion affected growth, survival, and health, compared with other commercially relevant functional marine ingredients. It was run over 64 days with shrimp starting at 2.15 g . and included an acute salinity challenge (drop from 20 to 5 ppt over 24 hours) to study robustness . Results for diets with CH revealed increased growth (Figure 1.a) and significantly higher survival after the salinity challenge (Figure 1.b). The second study was a 24-day specifically designed feed intake study performed by Matís in Iceland , in which various inclusion rates of CH and krill meal were tested to investigate their effect on the attractiveness of diets for whiteleg shrimp starting at 3.67 g. The results showed that feed intake increased significantly with higher inclusion rates of CH, compared with both control and krill meal (Figure 1.c).
Figure 1. Results from feeding trials with CH inclusion for whiteleg shrimp. a) Body weight at end of trial. b) Survival after salinity challenge. c) Feed intake relative to control. CTRL: Control. CH: Calanus hydrolysate. SLM: Squid-liver meal. KM: Krill meal. TH: Tuna hydrolysate. CH2/CH4/CH6: Calanus hydrolysate 2/4/6 % inclusion. KM2/KM3: Krill meal 2/3 % inclusion.