Production of South-American prawns based on replacement of fish meal with discarded brewer's yeast meal: effects on growth, survival, proximal composition and fecundity

REYES, P; CALVO N.S.; DE BONIS C. J.; MORA C.; CARVALHO D. A.

Shangai

Congreso; Global Conference on Aquaculture 2020; 2021

FAO

The replacement of fish meal with sustainable protein resources is a challenge to aquaculture feed. The quantity and quality of feed protein affect the growth, survival and fecundity of crustaceans. Macrobrachium borellii is an exclusively freshwater prawn, native to South America, with important features to aquaculture due to its easy management, omnivorous and generalist feeding habits, and abbreviated larval development. In this study, we evaluated growth, survival, proximal composition and fecundity of M. borellii cultivated with feeding that partly replaces fish meal (FM) with discarded brewer's yeast meal (YM). Juveniles of M. borellii were captured from the wild, placed in 9 tanks with PVC shelters (density: 178 individual/m2) and fed twice a day (7% biomass) with one of the diets during 75 days. Formulation of diets were: D1 (45% FM, 18% YM), D2 (35% FM, 25% YM), D3 (31% FM, 32% YM). Every 15 days, prawns were weighed and counted. At the end of the experiment ovigerous females were counted and placed in individual containers, fed with the same feed, and daily checked until the eggs hatched. The rest of the prawns were weighed and sacrificed to determine the proximal composition. Growth increment (GI), total biomass (B), survival (S), proximal composition (PC), and the percentage of ovigerous females successfully hatched (H) were compared. Juveniles fed with D1 showed GI significantly higher than those fed with D2 or D3. B, S and PC were similar among treatments. A positive relationship between YM replacement and H was found. Prawns cultivated with D1 grew faster, while diets with more YM tend to have a more successful reproductive stock. This indicates that YM might have other qualities for the reproductive stage. Results are useful to formulate diets with sustainable protein resources, reduce the carbon footprint of prawn farming and lower production costs.