Effects of including
cationic proteins from cod milt in the feed to Atlantic cod (Gadus morhua)
fry during a challenge trial with Vibrio anguillarum
G.M.
Pedersen, A. Gildberg, R.L. Olsen-2004
Aquaculture, 233(1-4): 31-43
Abstract:
This work was carried out to investigate if oral
administration of cationic cod milt proteins to cod fry could improve
disease resistance during a challenge trial with Vibrio anguillarum.
Atlantic cod fry (5 g) were given a commercial feed supplemented with 0.1%
cationic proteins extracted from cod milt. The pre-challenge feeding period
lasted 21 days, after which the fish were challenged for 1 h by bath
exposure to V. anguillarum (5×106 cfu ml-1).
Mortality was recorded during four weeks after challenge. From the 12th day
after infection and throughout the trial period, significant (p<0.05)
reduced cumulative mortality was registered in fish given the feed
supplemented by cationic cod milt proteins. Fish fed the supplemented diet
reached final cumulative mortalities of 59% and 66%, while 74% and 75%
mortality were recorded in fish given the control diet. The effect of the
cod milt cationic proteins on the growth of V. anguillarum was tested
using the broth dilution method. At 0–0.9% (w/v) NaCl, growth was
inhibited with MICs in the microgram range. These results suggest that
supplementation of cod milt cationic proteins to the feed of juvenile fish
improves their resistance to this bacterial infection.
(Norwegian Institute of Fisheries and Aquaculture
Research, Box 6122, N-9291, Tromsø, Norway, e-mail: guro.pedersen@fiskeriforskning.no)