@article{deck_salger_reynolds_tada_severance_ferket_egna_fatema_haque_borski_2023, title={Nutritional programming in Nile tilapia <i>(</i>Oreochromis<i> </i>niloticus<i>)</i>: Effect of low dietary protein on growth and the intestinal microbiome and transcriptome}, volume={18}, ISSN={["1932-6203"]}, DOI={10.1371/journal.pone.0292431}, abstractNote={Nutritional programming is the idea that early nutrient contributions can influence organismal structure or function and is documented in a variety of vertebrates, yet studies in fish are largely lacking. Tilapia are an important foodfish, with global production having increased rapidly since the 1990s. They exhibit high disease-resistance and grow well on formulated feeds which makes them an ideal aquaculture species, however incorporating high quality proteins into feeds can be costly. As feed constitutes 50–70% of total production costs in aquaculture, reducing protein content could curb these costs and increase revenue. Thus, we examined the effects of feeding Nile tilapia (O. niloticus) fry a restricted protein diet for the first 7–21 days on growth, gut microbial flora, and the intestinal transcriptome. Fish were fed either a 25% restricted or 48% control crude protein starter (ST) diet for up to 21 days and then switched to a 25% or 38% control crude protein growout (GO) diet. Fish fed a 25% ST diet for 14 days followed by a 38% GO diet had significantly higher lengths and weights and better feed efficiency than fish fed the control 48% ST and 38% GO diet after 56 days of culture. Growth of fry on the 25% ST, 7-day/38% GO and the 25% ST,7-day/25% GO diets did not differ from the those fed the control protein diets, while fish fed the 25% ST diet for 21 days had significantly lower growth and survival rates. We observed no significant differences in either alpha or beta diversity of the gut microbial flora between diets, however species richness (Shannon Index) was higher in fry fed the 25% protein ST diet regardless of the GO diet. Similarly, fish fed the 25% ST diet for 14 days followed by the 38% GO diet had minimal changes to the intestinal transcriptome relative to fish fed the control 48% ST and 38% GO diet. However, those fed 25% ST and GO diets for the entire 56 days exhibited substantial differences in the gut transcriptome from other groups showing gene expression profiles characteristic of detrimental changes to gut physiology, protein metabolism and immune function. Results suggest protein restriction for up to 14 days early in development leads to enhanced growth and feed efficiency with minimal effects on gut microbes or intestinal function. Protein restriction beyond this period appears detrimental to fish growth and health as underscored by expression of disease related genes and higher mortality rates.}, number={10}, journal={PLOS ONE}, author={Deck, Courtney A. and Salger, Scott A. and Reynolds, Hannah M. and Tada, Michael D. and Severance, Madeline E. and Ferket, Peter and Egna, Hillary S. and Fatema, Mst. Kaniz and Haque, Shahroz M. and Borski, Russell J.}, year={2023}, month={Oct} }
 @article{deck_mankiewicz_borski_2022, title={Evidence for a leptin-insulin axis in a fish, the tilapia (Oreochromis mossambicus)}, volume={253}, ISSN={["1479-6805"]}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-85124578276&partnerID=MN8TOARS}, DOI={10.1530/JOE-21-0139}, abstractNote={Leptin, insulin, and glucagon are involved in regulating glycaemia in vertebrates and play a role in the progression of obesity and type 2 diabetes. While mammals possess an ‘adipoinsular axis’ whereby insulin stimulates leptin release from adipocytes and leptin in turn feeds back on the pancreas to inhibit further insulin secretion, evidence of such an axis in non-mammalian vertebrates is unknown. We investigated the interactions between these glycaemic hormones and provide evidence for a leptin–insulin axis in a teleost fish, the tilapia. In the first study, we exposed hepatocytes to various concentrations of either insulin or glucagon to determine effects on leptin a (lepa) and then examined this in vivo with i.p. injections of both hormones. We also exposed isolated Brockmann bodies (pancreatic islets) to recombinant tilapia leptin A (rtLepA) and again followed this up with an i.p. injection to examine changes in insulin a and glucagon b. We found that glucagon increases lepa in vitroand in vivo, with the latter being 18-fold higher than saline-injected controls; however, the effects of rtLepA on glub were more variable. Insulin increased lepa by 2.5-fold in vitro and 70-fold in vivo, while rtLepA decreased insa at basal and increased it at high glucose concentrations. These data indicate that a leptin–insulin axis may be conserved among vertebrates and is thus essential for regulating nutrient balance but that the relationship is likely much more dynamic in teleosts as glycaemia is not as tightly regulated as it is in mammals.}, number={1}, journal={JOURNAL OF ENDOCRINOLOGY}, publisher={Bioscientifica}, author={Deck, Courtney A. and Mankiewicz, Jamie L. and Borski, Russell J.}, year={2022}, month={Apr}, pages={13–25} }
 @article{salger_reza_deck_wahab_baltzegar_murr_borski_2020, title={Enhanced biodiversity of gut flora and feed efficiency in pond cultured tilapia under reduced frequency feeding strategies}, volume={15}, ISSN={["1932-6203"]}, DOI={10.1371/journal.pone.0236100}, abstractNote={Feed constitutes 50–70% of total production costs of tilapia, one of the most widely cultured finfishes in the world. We evaluated reduced-feeding strategies for improving production efficiency of Nile tilapia (Oreochromis niloticus). In a 12-week pond trial, fish were fed daily, every other day, every third day, or not at all. Ponds were fertilized to enhance natural foods. In a fifth group fish were fed daily without pond fertilization. Fish fed daily with or without pond fertilization and fish fed every other day had higher specific growth rates, survivability, and net production than the other two treatments. Fish feed efficiency and benefit to cost ratio was highest for treatments fed in a pulsatile manner (i.e. fed every other day or every third day) with fish fed on alternate days providing the best net return among all groups. Fish fed on alternate days had more moderate gene expression levels of intestinal nutrient transporters which may allow for a more balanced and efficient nutrient uptake. Fecal microbe analyses identified 145 families of prokaryotic and 132 genera of eukaryotic organisms in tilapia. The highest diversity of prokaryotes was found in fish fed either every other day or daily in fertilized ponds and the highest diversity of eukaryotes was found in fish fed every other day. These studies indicate feeding Nile tilapia on alternate days along with weekly pond fertilization has no deleterious effects on growth, survivability, or production versus daily feeding regimes, but enhances feed efficiency by 76% and provides the greatest net return on investments. Our studies also suggest for the first time that combining alternate-day feeding with pond fertilization produces the greatest microbial biodiversity in the intestine that could contribute to enhanced feed efficiency and overall health of tilapia.}, number={7}, journal={PLOS ONE}, author={Salger, Scott A. and Reza, Jimi and Deck, Courtney A. and Wahab, Md Abdul and Baltzegar, David A. and Murr, Alexander T. and Borski, Russell J.}, year={2020}, month={Jul} }
 @article{mankiewicz_deck_taylor_douros_borski_2021, title={Epinephrine and glucose regulation of leptin synthesis and secretion in a teleost fish, the tilapia (Oreochromis mossambicus)}, volume={302}, ISSN={["1095-6840"]}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-85097432468&partnerID=MN8TOARS}, DOI={10.1016/j.ygcen.2020.113669}, abstractNote={Acute stress is regulated through the sympathetic adrenergic axis where catecholamines mobilize energy stores including carbohydrates as a principal element of the endocrine stress response. Leptin is a cytokine critical for regulating energy expenditure in vertebrates and is stimulated by various stressors in fish such as fasting, hyperosmotic challenge, and hypoxia. However, little is known about the regulatory interactions between leptin and the endocrine stress axis in fishes and other ectothermic vertebrates. We evaluated the actions of epinephrine and glucose in regulating leptin A (LepA) in vivo and in vitro in tilapia. Using hepatocyte incubations and a homologous LepA ELISA, we show that LepA synthesis and secretion decline as ambient glucose levels increase (10-25 mM). By contrast, bolus glucose administration in tilapia increases lepa mRNA levels 14-fold at 6 h, suggesting systemic factors regulated by glucose may counteract the direct inhibitory effects of glucose on hepatic lepa mRNA observed in vitro. Epinephrine stimulated glucose and LepA secretion from hepatocytes in a dose-dependent fashion within 15 min but had little effect on lepa mRNA levels. An in vivo injection of epinephrine into tilapia stimulated a rapid rise in blood glucose which was followed by a 4-fold increase in hepatic lepa mRNA levels at 2.5 and 6 h. Plasma LepA was also elevated by 6 h relative to controls. Recombinant tilapia LepA administration in vivo did not have any significant effect on plasma epinephrine levels. The results of this study demonstrate LepA is negatively regulated by rises in extracellular glucose at the level of the hepatocyte but stimulated by hyperglycemia in vivo. Further, epinephrine increases LepA. This, along with previous work demonstrating a hyperglycemic and glycogenolytic effect of LepA in tilapia, suggests that epinephrine may stimulate leptin secretion to augment and fine tune glucose mobilization and homeostasis as part of the integrated, adaptive stress response.}, journal={GENERAL AND COMPARATIVE ENDOCRINOLOGY}, publisher={Elsevier BV}, author={Mankiewicz, Jamie L. and Deck, Courtney A. and Taylor, Jordan D. and Douros, Jonathan D. and Borski, Russell J.}, year={2021}, month={Feb} }
 @article{iki_anderson_deck_ogihara_ikeba_kataoka_hyodo_2020, title={Measurement of 1 alpha hydroxycorticosterone in the Japanese banded houndshark, Triakis scyllium, following exposure to a series of stressors}, volume={292}, ISSN={["1095-6840"]}, DOI={10.1016/j.ygcen.2020.113440}, abstractNote={An endocrine glucocorticoid response following exposure to a stressor has been well described for many vertebrates. However, despite demonstration of secondary stress responses in a number of elasmobranchs, our understanding of the endocrine control of these responses is lacking. This is largely due to the unusual structure of the dominant corticosteroid in elasmobranch fish, 1α-hydroxycorticosterone (1α-OH-B). Here we describe plasma extraction and HPLC separation procedures that allowed for the measurement of 1α-OH-B and corticosterone from plasma samples in the cannulated, conscious free-swimming Japanese banded houndshark, Triakis scyllium. While patterns of concentration in the plasma for 1α-OH-B and corticosterone were found to be similar in all experiments conducted, circulating levels of 1α-OH-B were consistently 100-fold greater than circulating levels of corticosterone. Immediately following cannulation surgery, circulating levels of 1α-OH-B increased 7-fold compared to pre-surgery levels, while the levels were 11-fold higher than pre-stress levels 30 min post a repeated handling/air-exposure stress. A three week period of fasting resulted in a 22-fold increase in circulating levels of 1α-OH-B in the banded houndshark. This is the first report of direct measurement of changes in circulating levels of the primary corticosteroid in elasmobranch fish, 1α-OH-B, following exposure to a stressor such as handling/air-exposure. Data indicate the steroid may respond similarly to the classic glucocorticoid response, such as cortisol in teleosts.}, journal={GENERAL AND COMPARATIVE ENDOCRINOLOGY}, author={Iki, Ayuko and Anderson, W. Gary and Deck, Courtney A. and Ogihara, Mari H. and Ikeba, Kiriko and Kataoka, Hiroshi and Hyodo, Susumu}, year={2020}, month={Jun} }
 @article{nguyen_deck_pamenter_2019, title={Naked mole-rats reduce the expression of ATP-dependent but not ATP-independent heat shock proteins in acute hypoxia}, volume={222}, ISSN={["1477-9145"]}, DOI={10.1242/jeb.211243}, abstractNote={Naked mole rats (NMRs) are one of the most hypoxia-tolerant mammals identified and putatively experience intermittent and severe hypoxia in their underground burrows. Systemic physiological adaptions to hypoxia have begun to be investigated in this species; however, the cellular adaptations that underlie this tolerance remain poorly understood. Hypoxia compromises cellular energy production; and the maintenance of protein integrity when ATP generation is limited poses a major challenge. Heat shock proteins (HSPs) are cellular chaperones that are cytoprotective during hypoxia and we hypothesized that their expression would increase during acute hypoxia in NMRs. To test this hypothesis, we used qPCR and Western blot approaches to measure changes in gene and protein expression, respectively, of HSP27, HSP40, HSP70, and HSP90 in the brain, heart, liver, and temporalis muscle from NMRs following exposure to normoxia (21% O2) or hypoxia (7% O2 for 4, 12, or 24 hrs). Contrary to our expectations, we observed significant global reductions of ATP-dependant HSP70 and HSP90 (83% and 78%, respectively) after 24 hrs of hypoxia. Conversely, the expression of ATP-independent HSP27 and HSP40 proteins remained constant throughout the 24-hr hypoxic treatment in brain, heart and muscle. However, with prolonged hypoxia (24 hrs), the expression of HSP27 and HSP40 genes in these tissues was also reduced, suggesting that the protein expression of these chaperones may also eventually decrease in hypoxia. These results suggest that energy conservation is prioritized over cytoprotective protein chaperoning in NMR tissues during acute hypoxia. This unique adaptation may help NMRs to minimize energy expenditure while still maintaining proteostasis in hypoxia.}, number={22}, journal={JOURNAL OF EXPERIMENTAL BIOLOGY}, author={Nguyen, Vu Chau and Deck, Courtney A. and Pamenter, Matthew E.}, year={2019}, month={Nov} }
 @article{johnstone_honeycutt_deck_borski_2019, title={Nongenomic glucocorticoid effects and their mechanisms of action in vertebrates}, volume={346}, ISSN={["1937-6448"]}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-85064191568&partnerID=MN8TOARS}, DOI={10.1016/bs.ircmb.2019.03.004}, abstractNote={Glucocorticoids (GC) act on multiple organ systems to regulate a variety of physiological processes in vertebrates. Due to their immunosuppressive and anti-inflammatory actions, glucocorticoids are an attractive target for pharmaceutical development. Accordingly, they are one of the most widely prescribed classes of therapeutics. Through the classical mechanism of steroid action, glucocorticoids are thought to mainly affect gene transcription, both in a stimulatory and suppressive fashion, regulating de novo protein synthesis that subsequently leads to the physiological response. However, over the past three decades multiple lines of evidence demonstrate that glucocorticoids may work through rapid, nonclassical mechanisms that do not require alterations in gene transcription or translation. This review assimilates evidence across the vertebrate taxa on the diversity of nongenomic actions of glucocorticoids and the membrane-associated cellular mechanisms that may underlie rapid glucocorticoid responses to include potential binding sites characterized to date.}, journal={INTERNATIONAL REVIEW OF CELL AND MOLECULAR BIOLOGY, VOL 346}, publisher={Elsevier}, author={Johnstone, William M., III and Honeycutt, Jamie L. and Deck, Courtney A. and Borski, Russell J.}, year={2019}, pages={51–96} }
 @article{honeycutt_deck_miller_severance_atkins_luckenbach_buckel_daniels_rice_borski_et al._2019, title={Warmer waters masculinize wild populations of a fish with temperature-dependent sex determination}, volume={9}, ISSN={2045-2322}, url={http://dx.doi.org/10.1038/s41598-019-42944-x}, DOI={10.1038/s41598-019-42944-x}, abstractNote={AbstractSouthern flounder (Paralichthys lethostigma) exhibit environmental sex determination (ESD), where environmental factors can influence phenotypic sex during early juvenile development but only in the presumed XX female genotype. Warm and cold temperatures masculinize fish with mid-range conditions producing at most 50% females. Due to sexually dimorphic growth, southern flounder fisheries are dependent upon larger females. Wild populations could be at risk of masculinization from ESD due to globally increasing water temperatures. We evaluated the effects of habitat and temperature on wild populations of juvenile southern flounder in North Carolina, USA. While northern habitats averaged temperatures near 23 °C and produced the greatest proportion of females, more southerly habitats exhibited warmer temperatures (>27 °C) and consistently produced male-biased sex ratios (up to 94% male). Rearing flounder in the laboratory under temperature regimes mimicking those of natural habitats recapitulated sex ratio differences observed across the wild populations, providing strong evidence that temperature is a key factor influencing sex ratios in nursery habitats. These studies provide evidence of habitat conditions interacting with ESD to affect a key demographic parameter in an economically important fishery. The temperature ranges that yield male-biased sex ratios are within the scope of predicted increases in ocean temperature under climate change.}, number={1}, journal={Scientific Reports}, publisher={Springer Nature}, author={Honeycutt, J. L. and Deck, C. A. and Miller, S. C. and Severance, M. E. and Atkins, E. B. and Luckenbach, J. A. and Buckel, J. A. and Daniels, H. V. and Rice, J. A. and Borski, R. J. and et al.}, year={2019}, month={Apr} }
 @article{acharya-patel_deck_milsom_2018, title={Cardiorespiratory interactions in the Pacific spiny dogfish, Squalus suckleyi}, volume={221}, ISSN={["1477-9145"]}, DOI={10.1242/jeb.183830}, abstractNote={Elasmobranchs are a group of cartilaginous fish with no direct sympathetic innervation of the heart or gills. Fast cardiorespiratory regulation is controlled solely by the parasympathetic branch of the autonomic nervous system. Cardiovascular changes associated with ventilation are commonly present in the form of respiratory sinus arrhythmia (RSA) and as cardiorespiratory synchrony (CRS in which there is a 1:1 beat to breath ratio). The latter has been hypothesized to maximize oxygen uptake coupling the pulsatile flows of blood and water in the gills. Given this, we hypothesized that CRS should be more prevalent in situations of low oxygen supply and RSA should be abolished by vagotomy. To test this, we investigated the role of the vagus nerve in mediating cardiorespiratory responses to changing environmental oxygen conditions in the elasmobranch; Squalus suckleyi. Hypoxia and hyperoxia had little effect on heart rate but did alter breathing frequency and amplitude. Atropine yielded an overall tachycardia in all oxygen conditions and abolished all heart rate variability (HRV) suggesting that HRV solely reflects fluctuating vagal tonus on the heart. Regardless of the presence of atropine, hypoxia still induced an increase in ventilation rate and depth. CRS was only found during progressive hyperoxia post atropine when heart rate was uninhibited and ventilation was slowed due to the increase in oxygen supply suggesting that in Squalus suckleyi CRS is an epiphenomenon and not actively regulated to maximize gas exchange efficiency.}, number={17}, journal={JOURNAL OF EXPERIMENTAL BIOLOGY}, author={Acharya-Patel, Neha and Deck, Courtney A. and Milsom, William K.}, year={2018}, month={Sep} }
 @article{deck_anderson_conlon_walsh_2017, title={The activity of the rectal gland of the North Pacific spiny dogfish Squalus suckleyi is glucose dependent and stimulated by glucagon-like peptide-1}, volume={187}, ISSN={["1432-136X"]}, DOI={10.1007/s00360-017-1102-9}, abstractNote={Elasmobranchs possess a specialised organ, the rectal gland, which is responsible for excreting sodium chloride via the posterior intestine. Previous work has indicated that the gland may be activated by a number of hormones, some of which are likely related to the salt or volume loads associated with feeding. Furthermore, evidence exists for the gland being glucose dependent which is atypical for an elasmobranch tissue. In this study, the presence of sodium–glucose co-transporters (SGLTs) in the rectal gland and their regulation by feeding were investigated. In addition, the hypothesis of glucose dependence was examined through the use of glucose transporter (GLUT and SGLT) inhibitors, phlorizin, Indinavir, and STF-31 and their effect on secretion by the rectal gland. Finally, the effects on rectal gland activity of insulin, glucagon, and glucagon-like peptide-1, hormones typically involved in glucoregulation, were examined. The results showed that sglt1 mRNA is present in the gland, and there was a significant reduction in sglt1 transcript abundance 24 h post-feeding. An almost complete suppression of chloride secretion was observed when glucose uptake was inhibited, confirming the organ's glucose dependence. Finally, perfusion with dogfish GLP-1 (10 nmol L−1), but not dogfish glucagon, was shown to markedly stimulate the activity of the gland, increasing chloride secretion rates above baseline by approximately 16-fold (p < 0.001). As GLP-1 is released from the intestine upon feeding, we propose that this may be the primary signal for activation of the rectal gland post-feeding.}, number={8}, journal={JOURNAL OF COMPARATIVE PHYSIOLOGY B-BIOCHEMICAL SYSTEMIC AND ENVIRONMENTAL PHYSIOLOGY}, author={Deck, Courtney A. and Anderson, W. Gary and Conlon, J. Michael and Walsh, Patrick J.}, year={2017}, month={Dec}, pages={1155–1161} }