Respiratory metabolism and swimming performance in growth hormone transgenic Atlantic salmon

Abstract

We show that growth hormone enhanced transgenic salmon have a higher oxygen uptake during routine culture conditions and during forced swimming activity relative to similarly sized control fish. They also have a slightly higher critical oxygen level that limits oxygen uptake. However, they do not differ in regards to critical swimming speed. Growth hormone transgenic Atlantic salmon, Salmo salar, at 12-13°C were an F2 generation using eggs from a transgenic F1 female and milt from a nontransgenic male. They grew two to three times faster than control fish throughout the study period. Under routine culture conditions, both transgenic and control fish exhibited a diurnal cycle in oxygen uptake. However, oxygen uptake of transgenic fish was 1.7 times that of control fish at all times of the day. Oxygen uptake was independent of oxygen concentration above 10 mg/L in both groups of fish; critical oxygen uptake level was 6 mg/L in transgenic fish and 4 mg/L in control fish. During the oxygen decrease, transgenic fish and control fish lost equilibrium at the same low oxygen concentration levels. In the swim tunnel, oxygen uptake of transgenic fish was 1.6 times that of control fish at all swimming speeds. Critical swimming speeds did not differ between transgenic and control fish and were similar to literature values for salmonids.

Integration mechanisms of transgenes and population fitness of GH transgenic fish

“…and Coho salmon (Oncorhynchus kisutch), were found to have a greater oxygen uptake rate than control fish during routine feeding conditions. Additionally, transgenic fish have a greater daily feed intake in comparison to control fish [42,[46][47][48]. We found that the mean daily feed intake of GH transgenic common carp was 2.12 times greater than control fish during 4 days of feeding.…”

“…increased food consumption and feeding order, time spent in the feeding areas and the movement level [41]. GH-transgenic salmon are more active [42] and appear more risk-prone than non-transgenic fish, which may potentially increase their mortality from predation in the wild [43][44][45]. The appetite and feeding behavior of transgenic fish increase their competitive ability to obtain food resources, thus enhancing population viability.…”

Metabolism traits of ‘all-fish’ growth hormone transgenic common carp (Cyprinus carpio L.)

“…Studies of RMR in other transgenic fish species, including coho salmon and Atlantic salmon, found similar results (Stevens et al, 1998;Cook et al, 2000a;Leggatt et al, 2003). Therefore, transgenic fish have demonstrated an elevated routine oxygen uptake in order to meet their metabolic needs.…”

“…Other types of GH transgenic fish including Atlantic salmon (S. salar), tilapia (Oreochromis sp.) and coho salmon (O. kisutch), were found to have a greater oxygen uptake rate than control fish during routine feeding conditions (Stevens et al, 1998;Cook et al, 2000a,c;Mckenzie et al, 2003;Leggatt et al, 2003). Additionally, transgenic fish have a greater daily feed intake in comparison to control fish (Fu et al, 1998;Cook et al, 2000b;Rahman et al, 2001;Leggatt et al, 2003).…”

Increased food intake in growth hormone-transgenic common carp (Cyprinus carpio L.) may be mediated by upregulating Agouti-related protein (AgRP)

“…(Martinez et al, 1999;Rahman et al, 1998) and common carp (Cyprinus carpio L.) (Wang et al, 2001;Zhong et al, 2012). During recent years, it has become clear that elevated growth hormone (GH) levels in transgenic fish induce a wide range of effects apart from growth promotion (Devlin et al, 1994;Du et al, 1992;Martinez et al, 1996;Nam et al, 2001;Rahman et al, 1998;Wang et al, 2001;Zhong et al, 2012), including altered metabolism (Guan et al, 2008;McKenzie et al, 2003;Stevens et al, 1998), swimming performance (Farrell et al, 1997;Lee et al, 2003;Stevens et al, 1998), anti-predator behavior (Abrahams and Sutterlin, 1999;Duan et al, 2010;Dunham et al, 1999) and growth-related neuroendocrine regulation (Raven et al, 2008). In addition, GH treatment resulted in increased food intake and feeding behavior in normal fish (Johnsson and Bjornsson, 1994).…”