Page 76 - New additives and ingredients in the formulation of aquafeeds

Results obtained in the nutritional evaluation have proved that similar
amounts of either purified enzyme extracts (PEE) or crude enzyme extracts
(CEE) may result in equal improvement on nutritional efficiency. Since the
estimated cost of the CEE is much lower (Table 6), it will be considered in
the present study as the most suitable for inclusion in the feed.
The theoretical industrial process to prepare crude enzyme extracts differs
from that commercially developed to obtain purified enzymes. Hence, it was
designed using as a reference the process developed at laboratory scale.
The final product is a dry powder obtained after freeze-drying. Although
stabilization of the CEE could be achieved using a different and probably
less expensive procedure, this has been the selected method considered in
the study.
Table 5. Estimated amounts of enzyme extracts that could be obtained from the
viscera of fish species caught by the Spanish fleet (tonnes/year)
Species Catches Viscera
biomass
Crude enzyme
extract (CEE)
Purified enzyme
extract (PEE)
Redfish 4,180 334 50.10 9.02
Roughhead grenadier 851 68 10.20 1.15
Baird’s slickhead 1,643 131 19.65 1.71
Black scabbardfish 260 21 3.15 0.41
Blue ling 596 48 7.20 0.95
Greenland halibut 4,897 392 58.80 8.23
European hake 24,334 1,947 292.05 33.09
Megrim 249 20 3.00 0.48
Haddock 167 13 1.95 0.27
Blackbellied angler 6,021 482 72.30 10.12
Blue whiting 19,868 1,589 238.35 33.38
European pilchard 30,738 2,459 368.85 110.66
Argentine hake 13,421 1,074 161.10 31.14
Patagonian grenadier 12,106 968 145.20 26.15
Longtail southern cod 28,977 2,318 347.70 69.54
Pink cusk-eel 2,470 198 29.70 5.93
Argentine shortfin squid 80,000 6,400 960.00 217.60
74 Use of purified extracts from fish viscera as an enzyme additive in feeds for juvenile marine fish