Modern fish feeds are being formulated with increasing amounts of alternative plant protein sources (Naylor et al., 2009).
Increasing the amount of unpurified plant ingredients in feeds
will introduce fibers (i.e. non-starch polysaccharides, NSPs), which
are considered indigestible in fish (Lovell, 1998). Due to their low
digestibility and high structural integrity, fibers could potentially
change the particle size distribution of fecal waste and its subsequent
recovery with microscreens in recirculating aquaculture
systems (RAS). Furthermore, the low degradability of fibers could
hamper the use offeces as a carbon source in denitrification