Antisomatostatin-induced growth acceleration in chinook salmon (Oncorhynchus tshawytscha)

Since somatostatin (SRIF) inhibits the release of growth hormone (GH), its immunoneutralization may provide an alternative to GH therapy as a means of enhancing somatic growth in fish. The present study examined the feasibility of accelerating growth in juvenile chinook salmon by means of antiSRIF administration. Yearling salmon of Nicola River stock (BC, Canada) were injected intraperitoneally every 5 days, for a total of 40 days, with either SRIF (1 μg g-1 body wt.), antiSRIF (SOMA-10, 1 μg g(-1)), recombinant bovine GH (rbGH, 2.5 μg g(-1)), recombinant porcine GH (rpGH, 2.5 μg g(-1)) or saline (controls). No significant differences were observed in length, weight or final condition factor (k) between the SRIF-treated and control fish over the experimental period. However, the fish treated with the antiSRIF were significantly (p ≤ 0.05) longer and heavier than the control salmon after 25 and 30 days respectively. Furthermore, antiSRIF treatment caused a lowering in k when compared to the control salmon. Fish injected with rbGH or rpGH were significantly longer and heavier than all other groups (p ≤ 0.05), after only 5 days. GH treated groups also returned higher k when compared against all other treatments (p ≤ 0.05). No differences were observed in growth between the two rGH treatments over the experimental period.