Influence of fish feeds with plant proteins on sediment quality conditions: A microcosm experiment


by: Jirah P. Mamigo, Sheila Mae S. Santander-de Leon


Plant proteins have been widely utilized for aquaculture however its environmental effects remained understudied. A microcosm experiment was conducted to determine the effects of feed types (feeds with plant protein vs feeds with fishmeal only) and feed levels on sediment quality conditions. Sediments were treated with three feed types composed of different protein sources: a) fishmeal only (FM) b) soybean, copra, and fishmeal (SC); and c) soybean, wheat, and fish meal (SW) at low feed (LF, 0.07 g) and high feed (HF, 0.40 g) levels; and incubated for 20 days. Results revealed that all feed treatments created anoxic (redox potential, -103 to -135 mV) and toxic sulfidic sediment conditions (FM, > 2.5 mg. g-1, and SC and SW > 1.7 mg. g-1). Effects of differences in feed types were apparent on higher pore water Ammonium – N concentrations in plant-added fish feeds SC (414.08 ± 29.32 ppm) and SW (310.45 ± 113.18 ppm) than in FM (249.43 ± 86.95 ppm) at HF level. Protein concentration in sediments was highest in SW feed type. Effects of LF and HF did not show significant differences but both clearly showed poor sediment quality conditions when compared to sediments without feeds. The results suggest that the current use of plant-proteins as an alternative to fishmeal in aquaculture feeds may pose similar deleterious effects to sediment quality.

Keywords: fish feeds, plant protein, fishmeal, sediment quality, total sulfides