@article{picha_biga_galt_mcginty_gross_hedgpeth_siopes_borski_2014, title={Overcompensation of circulating and local insulin-like growth factor-1 during catch-up growth in hybrid striped bass (Morone chrysops Chi Morone saxatilis) following temperature and feeding manipulations}, volume={428}, ISSN={["1873-5622"]}, DOI={10.1016/j.aquaculture.2014.02.028}, abstractNote={Teleosts and other aquatic ectotherms have the ability to withstand prolonged periods of low water temperatures (cold-acclimation) and fasting, and can often respond with phases of accelerated (compensatory) growth when favorable conditions are restored. We assessed whether complete feed restriction prior to (24 °C, days 0–23) and/or during (14 °C, days 24–114) a simulated period of cold-acclimation could elicit episodes of compensatory growth (CG) and catch-up growth upon warm-up to 24 °C and satiation feeding (days 115–148). Control hybrid striped bass (HSB: Morone chrysops × Morone saxatilis) were fed to satiation throughout the entire experiment under these temperature fluctuations. Compensatory growth and ultimately catch-up growth were achieved in groups of HSB that were deprived of feed during either the initial period at 24 °C (days 0–23), during the cold-acclimation period (14 °C, days 24–114), or during both of these periods (days 0–114). Further, it appears that HSB are better able to compensate for weight loss when skeletal length is not significantly compromised during the treatment period, which occurred in HSB feed restricted during cold-acclimation only. The most dramatic CG responses were defined by specific growth rates (SGRs) up to 4.2 times that of controls and were accompanied by hyperphagia and improvements in temporal and overall feed conversion. Levels of plasma insulin-like growth factor (IGF)-1 and muscle IGF-1 mRNA were significantly correlated to growth rate for all groups throughout the experiment (R2 = 0.40, 0.23, respectively), with an overcompensation of both observed in HSB with the most elevated SGRs during the CG response. Interestingly, opposing trends were observed between muscle mRNA expression of growth hormone receptor (GHR)-1 and -2, with fasting at 24 °C and 14 °C resulting in depressed levels of GHR-1 and elevated levels of GHR-2 relative to controls. Levels of muscle myostatin (MSTN)-1 mRNA were significantly depressed in HSB fasted at 24 °C and/or 14 °C while MSTN-2 mRNA was lower following initial feed restriction at 24 °C. Likewise, levels of unprocessed pro-MSTN (precursor) and mature MSTN protein were both depressed in fasted fish at 24 °C. This study demonstrates that a previous period of feed restriction and cold-acclimation followed by realimentation at more favorable water temperatures produces a strong CG response and catch-up growth in fish. These studies also suggest that an overcompensation of circulating and local IGF-1 along with changes in MSTN mRNA and protein expression may contribute to accelerated growth rates characteristic of CG. Furthermore, our studies indicate that overall feed conversion can improve by as much as 30% with CG induced through temperature and feeding manipulations with no adverse effects on growth of HSB. This raises the possibility that CG protocols can improve production efficiency of HSB and other temperate teleosts in pond or tank culture.}, journal={AQUACULTURE}, author={Picha, Matthew E. and Biga, Peggy R. and Galt, Nicholas and McGinty, Andy S. and Gross, Kevin and Hedgpeth, Vickie S. and Siopes, Thomas D. and Borski, Russell J.}, year={2014}, month={May}, pages={174–183} }
 @article{duffy_picha_borsld_conover_2013, title={Circulating levels of plasma IGF-I during recovery from size-selective harvesting in Menidia menidia}, volume={166}, number={2}, journal={Comparative Biochemistry and Physiology. A, Molecular & Integrative Physiology}, author={Duffy, T. A. and Picha, M. E. and Borsld, R. J. and Conover, D. O.}, year={2013}, pages={222–227} }
 @article{won_baltzegar_picha_borski_2012, title={Cloning and characterization of leptin in a Perciform fish, the striped bass (Morone saxatilis): Control of feeding and regulation by nutritional state}, volume={178}, ISSN={["1095-6840"]}, DOI={10.1016/j.ygcen.2012.04.019}, abstractNote={In mammals, leptin is an anorexigenic peptide hormone that regulates energy homeostasis. It is produced predominantly by white adipose tissue and circulates as an endocrine indicator of energy reserves. Teleost leptin has been characterized in a few fish species, but its regulation is not well understood, particularly in response to nutritional status. In this study, we cloned a putative leptin in striped bass (Morone saxatilis) and report the first characterization of leptin in a Perciforme, the largest and most diverse order of fish. The striped bass leptin coding sequence was 65% homologous with pufferfish, 52% with Atlantic salmon, and 46% with human. PCR showed that leptin mRNA was exclusively expressed in the liver, and not adipose or other tissues. The leptin coding sequence of striped bass and the more widely cultured hybrid striped bass variety (HSB; Morone chrysops, white bass × M. saxatilis) were identical. We then evaluated whether the metabolic status of HSB might alter leptin gene expression. Juvenile HSB were subjected to 3 weeks feed deprivation followed by 3 weeks of refeeding. Quantitative PCR showed that fasting for 3 weeks reduced hepatic leptin mRNA levels relative to fed controls. Leptin mRNA levels then increased upon refeeding, albeit levels were not completely restored to those seen in control fish fed throughout the experiment. Intraperitoneal injection of human leptin suppressed appetite in HSB. In as much as hepatic HSB leptin mRNA is regulated by nutritional state and has a corresponding anorexigenic effect, our results suggest that leptin may play a role in energy homeostasis in these advanced Perciformes.}, number={1}, journal={GENERAL AND COMPARATIVE ENDOCRINOLOGY}, author={Won, Eugene T. and Baltzegar, David A. and Picha, Matthew E. and Borski, Russell J.}, year={2012}, month={Aug}, pages={98–107} }
 @article{duffy_picha_won_borski_mcelroy_conover_2010, title={Ontogenesis of Gonadal Aromatase Gene Expression in Atlantic Silverside (Menidia menidia) Populations With Genetic and Temperature-Dependent Sex Determination}, volume={313A}, ISSN={["2471-5646"]}, DOI={10.1002/jez.612}, abstractNote={Abstract}, number={7}, journal={JOURNAL OF EXPERIMENTAL ZOOLOGY PART A-ECOLOGICAL AND INTEGRATIVE PHYSIOLOGY}, author={Duffy, Tara A. and Picha, Matthew E. and Won, Eugene T. and Borski, Russell J. and McElroy, Anne E. and Conover, David O.}, year={2010}, month={Aug}, pages={421–431} }
 @article{picha_strom_riley_walker_won_johnstone_borski_2009, title={Plasma ghrelin and growth hormone regulation in response to metabolic state in hybrid striped bass: Effects of feeding, ghrelin and insulin-like growth factor-I on in vivo and in vitro GH secretion}, volume={161}, ISSN={["1095-6840"]}, DOI={10.1016/j.ygcen.2009.01.026}, abstractNote={The regulation of growth hormone (GH) secretion by ghrelin during variable metabolic states is poorly understood. We examined plasma GH and ghrelin in hybrid striped bass (HSB) undergoing seasonally-based feeding and temperature manipulations. Fasting for 21 days (d) at 24 degrees C resulted in catabolism and up-regulation of plasma GH and ghrelin relative to fed controls. Continued fasting during cold-banking (14 degrees C, 90 d) resulted in a further 43-fold increase in ghrelin while GH remained elevated. A subsequent 19 day refeeding period at 24 degrees C elicited hyperphagic and compensatory growth responses, accompanied by declines in ghrelin and GH. We then tested the role of ghrelin in stimulating GH release in vivo and in vitro. Intraperitoneal injections of ghrelin resulted in dose-dependent increases in plasma GH after 6 hours (h). Ghrelin also increased GH release from HSB pituitaries during 6h incubations. Lastly, we assessed how metabolic state, ghrelin and insulin-like growth factor-I (IGF-I) affect in vitro pituitary GH release. Spontaneous GH release was 5.2-fold higher from pituitaries of fasted compared with fed animals. Ghrelin was equally effective in stimulating GH release from pituitaries of fed and starved animals, while it was ineffective in enhancing GH release from pituitaries of starved (21 d) then refed (4d) HSB. Incubation with IGF-I inhibited GH release regardless of metabolic state. These studies are the first to show that seasonally-based periods of feed deprivation and low temperature yield sustained increases in GH secretion that are likely mediated, at least partially, through elevated ghrelin, reduced IGF-I negative feedback and fasting-induced spontaneous GH release.}, number={3}, journal={GENERAL AND COMPARATIVE ENDOCRINOLOGY}, author={Picha, Matthew E. and Strom, Christina N. and Riley, Larry G. and Walker, Alicia A. and Won, Eugene T. and Johnstone, William M. and Borski, Russell J.}, year={2009}, month={May}, pages={365–372} }
 @article{picha_turano_tipsmark_borski_2008, title={Regulation of endocrine and paracrine sources of Igfs and Gh receptor during compensatory growth in hybrid striped bass (Morone chrysops X Morone saxatilis)}, volume={199}, ISSN={["1479-6805"]}, DOI={10.1677/JOE-07-0649}, abstractNote={Compensatory growth (CG) is a period of growth acceleration that exceeds normal rates after animals are alleviated of certain growth-stunting conditions. In hybrid striped bass (HSB, Morone chrysops×Morone saxatilis), 3 weeks of complete feed restriction results in a catabolic state that, when relieved, renders a subsequent phase of CG. The catabolic state was characterized by depressed levels of hepatic Type I and II GH receptor (ghr1, ghr2) and igf1 mRNA, along with considerable decreases in plasma Igf1. The state of catabolism also resulted in significant declines in hepatic igf2 mRNA and in circulating 40 kDa Igf-binding protein (Igfbp). Skeletal muscle expression of ghr2 mRNA was significantly increased. Upon realimentation, specific growth rates (SGRs) were significantly higher than sized-matched controls, indicating a period of CG. Hepatic ghr1, ghr2, igf1 and igf2 mRNA levels along with plasma Igf1 and 40 kDa Igfbp increased rapidly during realimentation. Plasma Igf1 and total hepatic igf2 mRNA were significantly correlated to SGR throughout the study. Skeletal muscle igf1 mRNA also increased tenfold during CG. These data suggest that endocrine and paracrine/autocrine components of the GH–Igf axis, namely igf1, igf2, and ghr1 and ghr2, may be involved in CG responses in HSB, with several of the gene expression variables exceeding normal levels during CG. We also demonstrate that normalization of hepatic mRNA as a function of total liver production, rather than as a fraction of total RNA, may be a more biologically appropriate method of quantifying hepatic gene expression when using real-time PCR.}, number={1}, journal={JOURNAL OF ENDOCRINOLOGY}, author={Picha, Matthew E. and Turano, Marc J. and Tipsmark, Christian K. and Borski, Russell J.}, year={2008}, month={Oct}, pages={81–94} }
 @article{picha_silverstein_borski_2006, title={Discordant regulation of hepatic IGF-I mRNA and circulating IGF-I during compensatory growth in a teleost, the hybrid striped bass (Morone chrysops x Morone saxatilis)}, volume={147}, ISSN={["1095-6840"]}, DOI={10.1016/j.ygcen.2005.12.020}, abstractNote={Compensatory growth (CG) is a period of growth that exceeds normal rates after animals are alleviated of certain growth-stunting conditions. Little is known, however, about the endocrine control of CG in teleosts. So, our aim was to induce CG in juvenile hybrid striped bass (HSB, Morone chrysops × Morone saxatilis) through manipulations in feeding regimen, and then determine whether changes in circulating insulin-like growth factor-I (IGF-I) and hepatic IGF-I gene expression accompany the CG response. A considerable catabolic state was induced in HSB fed a total of two times over 4 weeks (once each in the 2nd and 3rd week). Negative energy balance was evidenced through weight loss (−3.4% BW) and a significant drop in hepatosomatic index (HSI) from a value of 3.71 to 1.46. Upon realimentation, in which HSB were fed ad libitum 2×/day, a significant CG response was observed over a 4-week period. The CG response was characterized by an elevated specific growth rate, hyperphagia, restoration of the HSI and an improvement in feed conversion, all relative to controls that were fed ad libitum 2×/day throughout the experiment. Moreover, the CG response and catabolic state preceding it were marked by a discordant regulation in the expression of hepatic IGF-I mRNA and plasma IGF-I levels, the latter parameter paralleling changes in growth (r2 = 0.56, P < 001). The catabolic state was accompanied by an 82% increase in hepatic IGF-I mRNA while levels of plasma IGF-I were significantly depressed relative to controls. During the subsequent CG response, however, hepatic IGF-I mRNA decreased by 61% while plasma IGF-I increased by 86%. The underlying mechanisms for this inverse regulation of hepatic IGF-I mRNA and circulating IGF-I are uncertain, but may reflect alterations in hepatic IGF-I mRNA production, stability, and translation such that hepatic IGF-I mRNA is accumulated during periods of catabolism and then rapidly translated and released into circulation when conditions improve. These results suggest that CG can be induced in HSB following a sufficient catabolic state and that systemic IGF-I may be an important mediator of the accelerated growth rate characteristic of CG.}, number={2}, journal={GENERAL AND COMPARATIVE ENDOCRINOLOGY}, author={Picha, Matthew E. and Silverstein, Jeffrey T. and Borski, Russell J.}, year={2006}, month={Jun}, pages={196–205} }
 @article{cruz_brown_luckenbach_picha_bolivar_borski_2006, title={Insulin-like growth factor-I cDNA cloning, gene expression and potential use as a growth rate indicator in Nile tilapia, Oreochromis niloticus}, volume={251}, ISSN={["1873-5622"]}, DOI={10.1016/j.aquaculture.2005.06.039}, abstractNote={IGF-I is a mitogenic polypeptide that is an important regulator of growth in fish. The potential of IGF-I mRNA abundance as a rapid growth indicator in the Nile tilapia, Oreochromis niloticus, was evaluated. Hepatic IGF-I cDNA was isolated and partially cloned. The partial sequence having 539 bases encodes for the signal peptide, mature protein and a portion of the E domain. The deduced 68 amino acid sequence for mature IGF-I showed 84–90% and 77–79% sequence identity with fish and mammalian counterparts, respectively. The deduced amino acid sequence for domains B and A was most conserved (93–97%) relative to other fishes. A sensitive TaqMan real time qRT-PCR assay for O. niloticus was developed based on the mature IGF-I peptide for measures of hepatic IGF-I mRNA levels. Hepatic IGF-I mRNA levels were found to be significantly correlated with growth rate of fish reared under different feeding regimes and temperature conditions. Higher feed consumption and water temperature produced faster-growing fish and increased hepatic IGF-I mRNA expression. These findings suggest that hepatic-derived IGF-I plays a key role in controlling growth in O. niloticus and indicates that IGF-I mRNA quantification could prove useful for the rapid assessment of growth rate in this species.}, number={2-4}, journal={AQUACULTURE}, author={Cruz, EMV and Brown, CL and Luckenbach, JA and Picha, ME and Bolivar, RB and Borski, RJ}, year={2006}, month={Feb}, pages={585–595} }
 @article{skalski_picha_gilliam_borski_2005, title={Variable intake, compensatory growth, and increased growth efficiency in fish: Models and mechanisms}, volume={86}, ISSN={["1939-9170"]}, DOI={10.1890/04-0896}, abstractNote={Resources fluctuate in space and time, and animals routinely experience temporally varying opportunities for resource intake, and variation in intake itself. We investigate consequences of such variation in intake on growth and growth efficiency (growth per unit intake) in juvenile hybrid striped bass. We observed, after statistically accounting for the effects of total consumption and initial body size, that individuals re- ceiving a low ration followed by a higher ration (the fluctuating ration) grew faster than individuals receiving a temporally constant ration (the normal ration). To interpret this increase in growth efficiency, we consider a set of alternative models representing different physiological hypotheses of the growth process. Using a simple growth model, an analytical result shows that the fluctuating ration as typically applied in experiments (a low ration followed by a high ration), independent of any change in physiology, increases growth efficiency relative to individuals on the normal ration. Growth efficiency increases because cumulative maintenance costs are lower for individuals that stay small initially and then grow rapidly in comparison to individuals that grow steadily. Further, a statistical analysis of alternative models inferred that fish receiving a variable ration show higher assimilation and/or conversion efficiencies of food and lower mass-specific maintenance costs. Our analysis suggests that the lower cumulative maintenance costs incurred over a time interval with low consumption followed by high consumption act in association with higher assim- ilation-conversion efficiencies, and lower overall mass-specific maintenance costs to in- crease growth efficiency in hybrid striped bass.}, number={6}, journal={ECOLOGY}, author={Skalski, GT and Picha, ME and Gilliam, JF and Borski, RJ}, year={2005}, month={Jun}, pages={1452–1462} }