Page 68 - New additives and ingredients in the formulation of aquafeeds

digestive function of the young fish. An interesting approach oriented to
enhance the nutritional value of such feeds for very young fish should be
the use of exogenous enzymes from marine origin that could increase
the hydrolysis of substrates within their digestive tracts. Taking this into
account, the main objective of the project ZIMOFEED (Cod. 08MMA003CT)
financed by the applied research sectorial programme of the Galician Plan
for R&D (INCITE) was to evaluate if the inclusion of partially purified enzyme
extracts obtained from fish viscera in feeds provided to juvenile marine fish
could result in an improvement in growth and feed efficiency. This objective
was assessed through a work plan comprising the following steps:
Preparation of an active and stabilized enzyme extract from fish viscera
Nutritional evaluation of the product
Feasibility study on potential industrial exploitation
Preparation
of an active
and stabilized
enzyme extract
from fish viscera
Species selection
Almost any commercial fish species could be a source of visceral extracts,
since all of them are subject to the evisceration process. Table 1 shows the
average annual catches (in the period 2007-2010) of different commercial
species by the Spanish fleet in the North Atlantic fishing grounds obtained
from FAO FishStat Plus.
Table 1. Catches (tonnes/year) and estimated amounts of viscera (tonnes/year)
by commercial species caught by Spanish fleet in the Atlantic fishing grounds
Common name FAO 3
α code Scientific name
Catches
(tonnes/
year)
Viscera
(tonnes/
year)
North Atlantic
Redfish RED Sebastes spp. 4,180 334
Roughhead grenadier RHG Macrourus berglax 851 68
Greenland halibut GHL Reinhardtius hippoglossoides 4,897 392
Roughsnout grenadier TSU Trachyrincus scabrus ** **
Atlantic horse mackerel HOM Trachurus trachurus ** **
Northeast Atlantic
Baird’s slickhead ALC Alepocephalus bairdii 1,643 131
Black scabbardfish BSF Aphanopus carbo 260 21
Blue ling BLI Molva dypterygia 596 48
Haddock HAD Melanogrammus aeglefinus 167 13
Blue whiting WHB Micromesistius poutassou 19,868 1,589
Northeast and Middle East Atlantic
Blackbellied angler* MNZ Lophius spp. 6,021 482
European hake HKE Merluccius merluccius 24,334 1,947
European pilchard PIL Sardina pilchardus 30,738 2,459
66 Use of purified extracts from fish viscera as an enzyme additive in feeds for juvenile marine fish