Assessing the capacity for compensatory growth in growth-hormone transgenic coho salmon Oncorhynchus kisutch.

The effect of feed cycling (consisting of periods of starvation followed by periods of refeeding to satiation) on compensatory growth was evaluated in growth hormone transgenic and non-transgenic wild-type coho salmon Oncorhynchus kisutch. The specific growth rate (G ) of feed-restricted non-transgenic O. kisutch was not significantly different from the G of fully-fed non-transgenic O. kisutch during two refeeding periods, whereas the G of feed-restricted transgenic O. kisutch was significantly higher in relation to the G of fully-fed transgenic O. kisutch during the second refeeding period, but not during the first, indicating that growth compensation mechanisms are different between non-transgenic and growth-hormone (GH)-transgenic O. kisutch and may depend on life history (i.e. previous starvation). Despite the non-significant growth rate compensation in non-transgenic O. kisutch, these fish showed a level of body mass catch-up growth not displayed by transgenic O. kisutch.