Comparison of vegetable shortening and cocoa butter as vehicles for cortisol manipulation in <scp><i>Salmo trutta</i></scp>

Birnie‐Gauvin, Kim; Peiman, Kathryn S.; Larsen, Mette Voldby; Aarestrup, Kim; Gilmour, Kathleen M.; Cooke, Steven J.

doi:10.1111/jfb.13513

Cited by 5 publications

(12 citation statements)

References 23 publications

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“…The decline of oxazepam in the implants over time closely reflected the decline of oxazepam in fish tissues and plasma over time, where CO-implants and implanted fish showed more stable oxazepam levels, while oxazepam in VS-implants and implanted fish declined quickly across the exposure period (Table , Figure S3). Previously, Birnie-Gauvin et al noted that VS-implants released a higher dose of cortisol to fish tissues than cocoa butter (not tested here) and attributed this, in part, to the soft texture of VS at low temperatures. In this study, VS and CO implants were both pliable at low temperatures when removed during dissection (∼5–10 °C), but CO implants were firmer (McCallum, E., personal observations).…”

Section: Resultsmentioning

confidence: 60%

“…For the means, any samples <LOQ were set to 1/2 the LOQ value (see Materials and Methods). Gauvin et al 30 noted that VS-implants released a higher dose of cortisol to fish tissues than cocoa butter (not tested here) and attributed this, in part, to the soft texture of VS at low temperatures. In this study, VS and CO implants were both pliable at low temperatures when removed during dissection (∼5−10 °C), but CO implants were firmer (McCallum, E., personal observations).…”

Section: Environmental Science and Technologymentioning

confidence: 65%

“…We prepared the implants by dissolving oxazepam (CAS 604-75-1, Merck) in one of two implant types, vegetable shortening (VS, Crisco, , a blend of soybean and palm oils) or coconut oil (CO, Kung’s Markatta Virgin Coconut Oil, ). These two substances were chosen because they remain pliable and soft at low temperatures characteristic of temperate freshwater environments, while other compounds (e.g., cocoa butter) harden and can create brittle implants with sharp edges. − These two substances are also commercially available, easily acquired, and cost-effective. We used three exposure treatments, a high dose (50 μg/g of implant), low dose (25 μg/g of implant), or control dose (0 μg/g, only implant with no oxazepam).…”

Section: Methodsmentioning

confidence: 99%

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Slow-Release Implants for Manipulating Contaminant Exposures in Aquatic Wildlife: A New Tool for Field Ecotoxicology

McCallum

Červený

Fick

et al. 2019

Environ. Sci. Technol.

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Field-based ecotoxicology studies are invaluable for uncovering the effects of contaminants of emerging concern (CECs) on aquatic organisms. However, large-scale exposures are still very rare due to prohibitive costs, the availability of replicated habitats, and the potential for exposure to cause lasting damage to the environment. Here, we evaluated the viability of internal slow-release implants as an alternative method for manipulating CEC exposures in aquatic wildlife using two fat-based carriers (coconut oil and vegetable shortening). We treated roach (Rutilus rutilus) with implants containing a high (50 μg/g), low (25 μg/g), or control (0 μg/g) concentration of the behavior-modifying pharmaceutical oxazepam. We then measured oxazepam uptake in four tissues (plasma, muscle, liver, and the brain) over 1 month. The two carriers released oxazepam differently: coconut oil was the superior implant type because it delivered a more consistent dose across time, while vegetable shortening released oxazepam rapidly at the start of the exposure period. For both carriers and treatments, the brain and liver contained the most oxazepam. Overall, the method is a promising technique for controlled manipulations of pharmaceuticals in fish, and we have provided some of the first data on the suitability and contaminant release kinetics from different implant types.

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Section: Resultsmentioning

confidence: 60%

Section: Environmental Science and Technologymentioning

confidence: 65%

Section: Methodsmentioning

confidence: 99%

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Slow-Release Implants for Manipulating Contaminant Exposures in Aquatic Wildlife: A New Tool for Field Ecotoxicology

McCallum

Červený

Fick

et al. 2019

Environ. Sci. Technol.

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“…We evaluated the implants' performance over a month-long period by analyzing the concentrations of fluoxetine in muscle, brain, and plasma via liquid chromatography tandem mass spectrometry. Given previous research using similar lipid-based carriers (see McCallum et al, 2019 for oxazepam, andBirnie-Gauvin et al, 2018 for cortisol), we generally expected that fluoxetine concentrations would initially increase and then decline in all tissues over the month as fluoxetine migrates from the implant to the surrounding fish tissues down a concentration gradient. We also predicted that fluoxetine would bioconcentrate to the highest concentrations in brain tissues versus muscle and plasma because of its higher lipophilicity (Duarte et al, 2022).…”

Section: Introductionmentioning

confidence: 92%

Cost‐Effective Pharmaceutical Implants in Fish: Validating the Performance of Slow‐Release Implants for the Antidepressant Fluoxetine

McCallum

Červený

Bose

et al. 2023

Enviro Toxic and Chemistry

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Internal, slow‐release implants can be an effective way to manipulate animal physiology or deliver a chemical exposure over long periods of time without the need for an exogenous exposure route. Slow‐release implants involve dissolving a compound in a lipid‐based carrier, which is inserted into the body of an organism. However, the release kinetics of the compound from the implant to body tissues also requires careful validation. We tested and validated a slow‐release implant methodology for exposing fish to a pharmaceutical pollutant, fluoxetine. We tested two lipid‐based carriers (coconut oil or vegetable shortening) in the common roach (Rutilus rutilus). The implants contained either a high (50 μg/g), low (25 μg/g), or control (0 μg/g) concentration of fluoxetine, and we measured tissue uptake in the brain, muscle, and plasma of implanted fish over 25 days. The two carriers released fluoxetine differently over time: coconut oil released fluoxetine in an accelerating manner (tissue uptake displayed a positive quadratic curvature), whereas vegetable shortening released fluoxetine in a decelerating manner (a negative quadratic curvature). For both carrier types, fluoxetine was measured at the highest concentration in the brain, followed by muscle and plasma. By comparing the implant exposures with waterborne exposures in the published literature, we showed that the implants delivered an internal exposure that would be similar if fish were exposed in surface waters containing effluents. Overall, we showed that slow‐release internal implants are an effective method for delivering chronic exposures of fluoxetine over at least 1‐month time scales. Internal exposures can be an especially powerful experimental tool when coupled with field‐based study designs to assess the impacts of pharmaceutical pollutants in complex natural environments. Environ Toxicol Chem 2023;42:1326–1336. © 2023 The Authors. Environmental Toxicology and Chemistry published by Wiley Periodicals LLC on behalf of SETAC.

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“…Sham and cortisol treatments applied in 2014 were performed the same way except vegetable shortening (100% vegetable shortening, Crisco, OH, USA) was used as a vehicle. A validation study showed that exogenous manipulation of high doses of cortisol in vegetable shortening increased plasma cortisol to supraphysiological levels for 6 days post-treatment, and plasma cortisol was still elevated but at normal stress-induced physiological levels at day 9 post-treatment, but high doses of cortisol in cocoa butter only increased plasma cortisol to normal stress-induced physiological levels at day 3 and had no effect by day 6 (Birnie-Gauvin et al, 2018). Fooddeprived fish were kept in a pen placed in the stream for 14 days to reduce foraging opportunities, which resulted in a loss of mass (Midwood et al, 2016;Peiman et al, 2017).…”

Section: Tagging and Treatmentsmentioning

confidence: 99%

No Evidence for Long-Term Carryover Effects in a Wild Salmonid Fish

Birnie‐Gauvin

Larsen²,

Peiman

et al. 2021

Physiological and Biochemical Zoology

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What is known: Early life experiences can influence fitness traits (e.g., growth, reproduction), and as such, any stimuli that affect these experiences may impact life histories and population dynamics. Carryover effects have been observed in a multitude of species, but there have been no attempts to manipulate stressors experienced by fish during early life phases to determine if they carry over to influence adult performance. What the study adds:We exposed wild juvenile brown trout to a range of stressors (cortisol injections, food deprivation, increased temperature and chase to exhaustion) and monitored migration for up to 4 years to determine whether these early life stressors had long-term effects.Despite having some short-term effects, we failed to detect long-term carryover effects from the stressors applied in early life in anadromous brown trout.

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Comparison of vegetable shortening and cocoa butter as vehicles for cortisol manipulation in Salmo trutta

Cited by 5 publications

References 23 publications

Slow-Release Implants for Manipulating Contaminant Exposures in Aquatic Wildlife: A New Tool for Field Ecotoxicology

Slow-Release Implants for Manipulating Contaminant Exposures in Aquatic Wildlife: A New Tool for Field Ecotoxicology

Cost‐Effective Pharmaceutical Implants in Fish: Validating the Performance of Slow‐Release Implants for the Antidepressant Fluoxetine

No Evidence for Long-Term Carryover Effects in a Wild Salmonid Fish

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