Gene–environment interactions influence feeding and anti‐predator behavior in wild and transgenic coho salmon

Abstract

Environmental conditions are known to affect phenotypic development in many organisms, making the characteristics of an animal reared under one set of conditions not always representative of animals reared under a different set of conditions. Previous results show that such plasticity can also affect the phenotypes and ecological interactions of different genotypes, including animals anthropogenically generated by genetic modification. To understand how plastic development can affect behavior in animals of different genotypes, we examined the feeding and risk-taking behavior in growth-enhanced transgenic coho salmon (with two- to threefold enhanced daily growth rates compared to wild type) under a range of conditions. When compared to wild-type siblings, we found clear effects of the rearing environment on feeding and risk-taking in transgenic animals and noted that in some cases, this environmental effect was stronger than the effects of the genetic modification. Generally, transgenic fish, regardless of rearing conditions, behaved similar to wild-type fish reared under natural-like conditions. Instead, the more unusual phenotype was associated with wild-type fish reared under hatchery conditions, which possessed an extreme risk averse phenotype compared to the same strain reared in naturalized conditions. Thus, the relative performance of genotypes from one environment (e.g., laboratory) may not always accurately reflect ecological interactions as would occur in a different environment (e.g., nature). Further, when assessing risks of genetically modified organisms, it is important to understand how the environment affects phenotypic development, which in turn may variably influence consequences to ecosystem components across different conditions found in the complexity of nature.

Growth-Enhanced Transgenic Coho Salmon (Oncorhynchus kisutch) Strains Have Varied Success in Simulated Streams: Implications for Risk Assessment

“…Other studies have also demonstrated a survival advantage of T MT over W fish in severe growth-limiting conditions [20, 21]. Due to low anti-predator behavior observed in T MT strain fish [31, 32], GH transgenic fish are expected to have lower survival than W fish under predation pressure, as has been observed in some studies [20, 33], but not others [21]. T MT fry had inconsistent relative survival in the presence of predators, where survival was higher than W fry at medium food levels in Exp.…”

“…3. Difference in rank survival of T MT and W fry within experiments may be due to increased foraging and decreased predator avoidance behavior observed in GH transgenic fish [27, 31, 32, 34–36], providing advantages or disadvantages to T MT fry depending on food availability and predator presence. The factors causing differences in rank order among equal conditions in different studies are not known, but could include age and relative size at entry, length of trial, competitive ability of different co-habiting T H3 strains, and/or amount of refuge areas in substrate (i.e.…”

“…as provided by gravel versus artificial turf in Experiment 2 versus 3 respectively), all which may influence the potential to form dominance hierarchies for shelter spaces, or influence cannibalistic or risk taking behavior in T MT and/or W fry (e.g. [27, 32, 37, 38]).…”

Effects of Domestication on Fish Behaviour

“…Now, the existence of transgenic species offers a good tool to study this problem. By comparing wild-type siblings and transgenic individuals, Sundström et al [50] found that wild and transgenic animals behave in the manner under natural like conditions; but until now, there are not a sufficient number of studies to conclude that genetically modified organisms are not affected by the complexity of natural conditions.…”

Effect of food deprivation on neuropeptide Y immunoreactivity and concurrent biochemical and gonadal responses in tilapia Oreochromis mossambicus (Peters, 1852)

“…The feeding behaviour of animals is complex and the acts of feeding and ingestion are the final results of a number of factors between the animal and its ecological interactions (Sundstrom et al, 2016). Neuropeptide Y (NPY), a 36 amino acid peptide, is one of the most conserved neuroendocrine peptides (Larhammar, 1996) and is known to be involved in the regulation of feeding behaviour in mammals (Schwartz et al, 1993;Stanley, 1993;Kaiyala et al, 1995), amphibians (Crespi et al, 2004) as well as in fish (Subhedar, 2006;Volkoff, 2016;Yan et al, 2017).…”