Author:

Keywords:

Astacus astacus, nutrition, aquaculture, diversification, RAS, crayfish

Abstract:

To date, there is no significant crayfish production in Belgium. However, marketing studies show a great potential for noble crayfish consumption. Recently several farmers and entrepreneurs started to show an interest in crayfish culture, as an addition to their core activity. Since no specific commercial feeds are available for noble crayfish, it’s important to find a readily available diet, suiting the crayfishes’ nutritional demands. Therefore, seven feeds were tested on two-summer-old noble crayfish in an indoor recirculating system: three commercial diets (pellets for shrimp, marine fish and carp), and four vegetable diets (alfalfa, potatoes, a soy/rapeseed mixture and beets). The effect of these different feeds on growth, survival rate and cheliped loss was evaluated. Of all treatments, the carp feed resulted in the highest specific growth rate (SGR) (0,34±0,03%.day-1, p=0,005) and the lowest loss of chelipeds (6,93±8,07%, p=0,028). Poorest SGR was observed in crayfish fed beets: 0,01±0,04%.day-1. The effect of feed on survival rate, appeared to be gender dependent (p=0,038). Males showed best survival rates when fed marine fish feed (100±0,00%) and carp feed (93,33±5,77%), while females showed highest survival rates when fed carp feed (100±0,00%) and shrimp feed (96,67±5,77%). When data of males and females are combined, the highest survival rates were obtained using carp feed (96,67±2,89%) and marine fish feed (96,67±5,77%) (p=0,006). Worst survival rates were observed in crayfish fed alfalfa (80,00±10,00%), potatoes (80,00±5,00%) and beets (80,00±10,00%). Most satisfying results for both growth, survival and loss of chelipeds were obtained with the carp feed. This result is especially interesting for farmers, as carp feed was the cheapest feed of all commercial diets tested. Although performance was significantly lower for vegetable feeds, these feeds could be an interesting addition to commercial pellets in order to lower feeding costs. An optimal commercial/vegetable feed ratio will be determined in a future experiment.