Spirulina Arthrospira platensis and processing industry fishery by-products as alternative protein sources to marine origin meals in weaning diets of mugil Liza aurata

Abstract

The present study evaluated the use of Arthrospira platensis cyanobacterium and fish by-products as alternative protein sources in Liza aurata larvae of 31 dph (days post-hatching) with an initial weight and length of 1.92±0.12 mg and 10.47±1.01 mm, respectively. Five microdiets were tested: Control diet, with 100% protein from squid meal; Arth10, Arth20 and Arth40 diets with 10%, 20% and 40% A. platensis as partial substitution of squid meal; and Circular diet, with 100% squid meal substitution by fishery by-product. This research revealed that Spirulina can be included in the microdiet of mullets up to 40% maximum selected replacement, reporting high growth rates in size and weight, as well as high survival rates and resistance to stress. The inclusion of aquafeed by-products, despite reflecting significantly lower growth, it presented similar survival rates and proximal composition in L. aurata larvae. The skeletal anomalies analysis showed that mullet larvae do not present high percentages of severe deformities, except for the presence of stones in the urinary ducts. These results open a path towards sustainability for L. aurata production and the use of fisheries by-productresources, giving rise to a circular economy necessary for the aquaculture sector.