Page 71 - New additives and ingredients in the formulation of aquafeeds

Protease and lipase ac*vi*es in freeze dried extracts (U/g)
40.3
55.7
60.4
61.0
23.7
55.4
38.5
8.0
1.2
0.2
8.2
5.9
0 20 40 60 80
4,093
4,328
4,690
6,076
6,141
7,017
7,334
7,525
7,555
8,609
8,955
10,152
0 2,000 4,000 6,000 8,000 10,000 12,000
Pink cusk-­‐eel
Patagonian grenadier
Redfish
Black scabbardfish
European pilchard
Haddock
Longtail southern cod
European hake
Argen<ne shorAin squid
Atlan<c horse mackerel
Megrim
Baird's slickhead
PROTEASE LIPASE
0 2,000 4,000 6,000 8,000 10,000 12,000
developed through seven different steps (Figure 2). In addition to the PEE,
some extracts used in one of the experiments did not undergo purification/
concentration with ammonium sulphate and were identified as Crude Enzyme
Extracts (CEE). The amount of fresh tissue required to prepare 1 g of PEE
ranged from 22 g (European pilchard) to 75 g (Baird’s slickhead). The activity
of protease and lipase activities determined in PEE, which showed an almost
inverse relationship, is detailed in Figure 3.
Characterization of protease activity
One of the main requisites for the use of PEE at industrial scale is that
enzyme activities should resist both the thermal conditions used in the
Figure 3: Protease
and lipase activities in
freeze dried extracts
(U/g)
Use of purified extracts from fish viscera as an enzyme additive in feeds for juvenile marine fish 69
Figure 4. Incubation of
PEE at different pHs,
temperatures and
time periods