Fj. Alarcon et al., Effect of inhibitors present in protein sources on digestive proteases of juvenile sea bream (Sparus aurata), AQU LIV RES, 12(4), 1999, pp. 233-238
The presence of protease inhibitors in different ingredients used in fish f
eeds may negatively affect their digestive utilisation. The effect of inhib
itors present in several protein sources on the activity of digestive prote
ases of sea bream was assessed using 'in vitro' assays. Inhibition produced
by extracts of plant proteins ranged from 25 to 50 % of total activity, wh
ereas that obtained using animal protein sources ranged from 1 to 20 %. The
exception was ovoalbumin, which showed the highest measured value (62 %).
A plot of the inhibition values obtained by changing the relative concentra
tions enzyme/inhibitor resulted in different curves for different protein s
ources. The use of sodium dodecyl sulphate polyacrylamide gel electrophores
is (SDS-PAGE) zymograms allowed visualisation of the aforementioned differe
nces in inhibition. The importance of measuring protease inhibition in the
preliminary evaluation of fish feed ingredients is discussed. (C) 1999 Ifre
mer/Cnrs/Inra/Ird/Cemagref/Editions scientifiques et medicales Elsevier SAS
.