Page 24 - Aquauclature Research and Studies (01)

AQUAUCLATURE
14
Research and Studies 1 (1): 15-01, 2026 page of 193

1995; Riche and Brown 1996). The presence of phytate in diets has also been
shown to minimize the digestion of proteins (Cheryan and Rackis, 1980) and
reduce the growth of chinook salmon and rainbow trout (Richardson et al.,
1985). In the present study, pre-treatments reduced the phytic acid level in
CSGM by 64-71%, and despite having the lowest phytate content, autoclaved
had significantly reduced the digestibility of CGSM minerals by 38%.
Trypsin inhibitors are crystalline globular proteins that block or lower
pancreatic trypsin and chymotrypsin activity that break down and digest pro-
teins (Agbo, 2008; Liener and Kakade, 1980). Autoclaving can reduce the
high concentration of trypsin inhibitors in SBM by up to 90% (Arndt et al.,
1999). The pre-treated SBM, in turn, improves the coefficient of total tract
apparent digestibility in rainbow trout by 91.5%. However, Makkar and
Becker (1999) reported that the carp growth is not affected by the trypsin

inhibitor level (24.8%) in Jatropha seed, indicating that the species is tolerant
to trypsin inhibitors. In this study, the trypsin inhibitor was reduced by 36-
82% by pre-treatments while protein digestibility significantly improved by
31-40%.
Saponins are steroid or triterpenoid glycosides found in many potential
alternative plant-based feed ingredients for aquaculture but are considered
toxic and a growth retardant in fish (Siddhuraju and Becker, 2003). Saponins
−1
are found in the range of 18–67 mg kg in various leguminous seeds includ-
ing defatted roasted soybean meal (Fenwick et al., 1991). Lupine seed meal
contains 1.1% and higher saponins adversely affect the digestion of dietary
protein in rainbow trout by 34% (De la Higuera et al., 1988). Dietary inclu-
sion of mucuna seed that contains 35% saponins also reduces the growth of
Nile tilapia (Siddhuraju and Becker, 2003). However, a reduction in saponins
via hydrothermal pre-treatment improves fish growth performance and feed
efficiency. In this study, Soaking and autoclaving treatments effectively re-
duced the saponins concentration in CSGM by 36.36% and 51.50%, and im-
proved the apparent protein digestibility by 31-40%.
CSGM contains high levels of fiber, and total soluble and insoluble non-
starch polysaccharides, NSPs as galactomannans (Barak and Mudgil, 2014),
which are higher than values reported for other legumes such as peas and