Author(s): L Tran, TC Nhut, KB Alfrey, FT Barrows, D Kuhn and E McLean

Abstract: Pacific white leg shrimp were stocked (150 PL m-3) into one of four plastic-lined 1000 m3 (0.1 ha) ponds. Ponds were randomly fed one of two diets in duplicate: a commercial shrimp feed (Grobest® Vista Eco), or an open formula, experimental, fishmeal and fish oil-free diet (F3). Shrimp were fed by hand and automatic feeders using commercial feed tables for 56 days. Sub-samples of shrimp (n = 50) were weighed weekly from each pond to evaluate growth and adjust feeding rates. Following harvest, no differences were observed between diets for survival. Combined pond biomass was 2045.0±45.96 kg (S.D.) and 2302.5±28.99 kg for commercial and F3 shrimp respectively. FCR were 1.15±0.00 and 1.03±0.01 (P< 0.05). Individual F3 fed shrimp were significantly (P< 0.05) heavier at trial termination with animals fed the commercial diet weighing 18.03±0.24 g versus 23.25±0.84 g (P< 0.05). Total hemocyte counts were 33.26±0.46 and 33.88±0.72, that for semi-granular cells 20.19±1.65 and 18.72±0.81, granular cells, 15.20±1.39 and 15.56±0.15, hyaline cells, 64.62± 3.01 and 65.72±0.96, and phenoloxidase activity, 56.87±6.12 and 50.29±0.55, for commercial and F3 fed shrimp respectively. A basic economic analysis indicated increased profitability for the F3 fed shrimp (US$7362.43 versus US$10665.62) with a return on investment (ROI) of 64.5% for the commercial feed and 89.8% for the F3 ponds. There were no differences between samples for proximate composition, cooked tail color as assessed by a BASF Salmon Color Fan or texture, as determined by a texture analyzer. Results from this trial unconditionally demonstrate the practicality of cultivating white leg shrimp using marine resource-free-based diets without impacting growth performance or consumer acceptability, while returning increasing ROI.

DOI: 10.22271/fish.2022.v10.i4a.2702

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