Gene transfer: potential to enhance the genome of Atlantic salmon for aquaculture

Abstract

Over the past 20 years we have generated stable lines of transgenic Atlantic salmon possessing either antifreeze protein (AFP) genes or a salmon growth hormone (GH) gene construct. The AFP gene transfer studies were initiated in 1982. The AFP transgene integrated into salmon genomic DNA and AFP has been found in the blood of all 5 generations to date. However, AFP levels are low and a means to raise these levels needs to be developed. Our GH gene transfer studies were initiated in 1989. Evidence to date indicates that a single copy of the GH transgene integrated into chromosomal DNA and has been passed down in Mendelian fashion, along with its rapid growth phenotype, over 6 generations. Laboratory studies indicate that our GH transgene enhances growth rates with Atlantic salmon reaching market size (4–6 kg) a year earlier than non-transgenics cultured commercially in Atlantic Canada. This GH gene transfer technology was patented and licensed to Aqua Bounty Farms Inc., and the transgenic salmon are currently under review by various government regulatory authorities in the USA and Canada for use in commercial aquaculture ventures. Our experience with the regulatory authorities, the industry and the press indicates that the successful introduction of transgenic salmon into the aquaculture industry involves issues concerning not only science but also food safety, environmental safety, animal welfare and consumer acceptance. This communication centres on our experience with Atlantic salmon and outlines our plans and progress towards demonstrating the safety of transgenic fish to the consumer and to the environment.

Myogenesis and muscle metabolism in juvenile Atlantic salmon (Salmo salar) made transgenic for growth hormone

“…The line of salmon used in this study grow to be 5-10 times larger than non-transgenic controls within the first 12·months of feeding (Fletcher et al, 2004) and are capable of reaching market size 1·year earlier than standard salmon currently cultured in Atlantic Canada (Fletcher et al, 2004;Deitch et al, 2006). The mechanism(s) responsible for such rapid growth in transgenic salmon especially at the very early stages (0-4·months) has yet to be resolved (Hill et al, 2000).…”

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

“…Since the first batch of transgenic fish was produced (Zhu et al, 1985), transgenesis has been used in many fish species (Hu and Zhu, 2010). To date, several stable lines of growth-enhanced transgenic fishes have been generated, including Atlantic salmon (Salmo salar) (Fletcher et al, 2004), coho salmon (Oncorhynchus kisutch) (Devlin et al, 2004), mud loach (Misgurnus mizolepis) (Nam et al, 2002), tilapia (Oreochromis sp.) (Martinez et al, 1999;Rahman et al, 1998) and common carp (Cyprinus carpio L.) (Wang et al, 2001;Zhong et al, 2012).…”

Effects of growth hormone over-expression on reproduction in the common carp Cyprinus carpio L.

“…To date, five stable lines of GH-transgenic fish have been generated, including Atlantic salmon (Salmo salar) (Fletcher et al, 2004;Rokkones et al, 1989), coho salmon (Oncorhynchus kisutch) , tilapia (oreochromis niloticus) (Rahman et al, 1998), mud loach (Misgurnus mizolepis) (Nam et al, 2002) and common carp (Cyprinus carpio) (Wang et al, 2001;Zhong et al, 2012). However, because of the potential ecological risk of transgenic fish, none of these fish have yet been produced for the intended goal of commercial use and human consumption (Devlin et al, 2006;Hu et al, 2006Hu et al, , 2007Hu and Zhu, 2010).…”