Lat. Am. J. Aquat. Res., 46(3): 558-569Thermal, 2018 biology and respiratory metabolism in Macrobrachium tenellum 558 1 “II International Congress of Macrobrachium” Fernando Vega-Villasante, Marcelo Ulises García-Guerrero, Carlos Alfonso Álvarez-González Luis Héctor Hernández-Hernández & Saúl Rogelio Guerrero Galván (Guest Editors) DOI: 10.3856/vol46-issue3-fulltext-9 Research Article Thermal preference, critical thermal limits, oxygen routine consumption and active metabolic scope of Macrobrachium tenellum (Smith, 1871) maintained at different acclimation temperatures Pedro Hernández-Sandoval1, Fernando Díaz2, Ana Denisse Re-Araujo2, J. Armando López-Sánchez3 María del Carmen Martínez-Valenzuela4, Marcelo García-Guerrero5 & Carlos Rosas6 1Programa de Doctorado en Ciencias Biológico Agropecuarias, Universidad Autónoma de Nayarit Unidad Académica de Ingeniería Pesquera, Instituto de Investigación en Ambiente Los Mochis Sinaloa, México 2Laboratorio de Ecofisiología de Organismos Acuáticos, Departamento de Biotecnología Marina Centro de Investigación Científica y de Educación Superior de Ensenada Ensenada, Baja California, México 3Programa de Doctorado en Ciencias Biológico Agropecuarias Unidad Académica de Ingeniería Pesquera, Universidad Autónoma de Nayarit, Nayarit, México 4Instituto de Investigación en Ambiente Los Mochis, Sinaloa, México 5Instituto Politécnico Nacional, Centro Interdisciplinario de Investigación para el Desarrollo Integral Regional Unidad Oaxaca, Laboratorio de Acuacultura, Oaxaca, México 6Unidad Multidisciplinaria de Docencia e Investigación, Facultad de Ciencias Universidad Nacional Autónoma de México, Mérida, México Corresponding author: Fernando Díaz ([email protected]) ABSTRACT. Temperature is one of the most dominant environmental factor influencing the biology and performance of aquatic ectotherms in the wild and in culture conditions. Thus, the aims of the present study were to investigate thermoregulatory behavior, thermal tolerance and active metabolic scope in Macrobrachium tenellum. To fulfill our goal, we measure, the preferred temperature, critical threshold limits, thermal window width, oxygen consumption routine rate and active metabolic scope in the prawn M. tenellum acclimated to 20, 23, 26, 29 and 32°C. The preferred temperature obtained by the graphic acute method was 28.5°C. Acclimation temperature significantly affected the thermal tolerance which increased with the acclimation temperature. The scope for thermal tolerance had an interval of 25.3 to 27.7°C. The thermal window calculated for M. tenellum was 325°C2. The acclimation response ratios had an interval of 0.42-0.50. These values allow us to characterize these species as inhabitants of subtropical and tropical regions. The oxygen consumption routine rates increased as the acclimation temperature increased from 20 to 32°C. The range of temperature coefficient (Q10) between 29-32°C was the lowest, at 1.98. The active metabolic scope for prawns was the lowest for organisms acclimated to 20 and 32°C and the highest value was obtained at 29°C. The results obtained in the present study are important to determine the optimum conditions in which M. tenellum needs to live in the natural environment and may partially explain their wide distribution pattern along the Mexican Pacific Ocean littoral. Keywords: Macrobrachium tenellum, preferred temperature, thermal tolerance, metabolic rate, aquaculture. INTRODUCTION production and feeding regime of this species (Cuevas, 1980; Hernández-Rodríguez et al., 1995, 1996; The freshwater prawn Macrobrachium tenellum Hernández-Rodríguez & Bückle, 1997; Signoret et al., (Smith, 1871) is distributed in fresh and brackish 1997; Aguilar et al., 1998; Arana et al., 2001; García- waters, along the coastal tropical and subtropical Ulloa et al., 2008; Rodríguez-Flores et al., 2012). Pacific from northern Mexico to Peru (Holthuis, 1980; Thermoregulatory behavior of ectothermic orga- Espinoza-Chaurand et al., 2011). Previous studies nisms is an important physiological response used to focused on oxygen concentrations, temperature, determine the temperature range under which the salinity, nutrition, density effect, larval or juvenile physiological and metabolic processes are optimum 255 9 Latin American Journal of Aquatic Research (Bellgraph et al., 2010; Ward et al., 2010; Xu et al., behavior but also how different species are adapted to 2015). Recently, behavioral thermoregulation has live in specific environments successfully (Pörtner, received renewed attention, in relation to the mecha- 2002, 2006, 2010, Pörtner et al., 2005; Pörtner & nisms that ectotherms use to cope with climate change Farrell, 2008; Noyola et al., 2015). effects (Dülger et al., 2012; Piaseĉknà et al., 2015; The absolute aerobic scope (AS), calculated as the Lattuca et al., 2017). difference in O2 consumption between the standard The measurement of the metabolic rate has been metabolic rate (SMR) and the maximum metabolic rate used as a tool to determine the impact that several (MMR) (Chabot et al., 2016; Farrell, 2016), represents environmental factors can have, such as the temperature, the excess oxygen available for biological fitness; salinity or exposure to pollutants, allowing us to besides growth, reproduction and activity. When determine the energetic costs that these combinations metabolic rates measured in animals acclimated at have on the organism (Lemos et al., 2001; Altinok & different temperatures two curves obtained (Fry, 1947). Grizzle, 2003; Brougher et al., 2005). The oxygen While the aerobic metabolism and temperature consumption is intimately associated with the normally show that, in extreme temperatures, the metabolic work and the energy flow that the organism difference between SMR and MMR is close to zero can use for the homeostatic control mechanisms (Ferreira et al., 2014). Aerobic scope, as with other (Salvato et al., 2001; Das et al., 2005). physiological functions has an optimum temperature According to Pörtner & Farrel (2008) variations in range (Topt). Beyond this optimum point, temperature water temperatures that may occur in its natural habitat causes energy to channel for protection (pejus interval due to changes of the season and global climate change of temperature) or to repair the cellular integrity of and thermal tolerance capacity might be the key on individuals (pessimum range) (Pörtner & Knust, 2007; physiological traits for their survival in the field. It is Pörtner, 2010). very important to know the critical thermal maxima The preferred temperature Tpref and physiological (CTmax) and the critical thermal minimum (CTmin), AS measures could predict the temperature at which because those limits are considered a measure of organism’s productivity is optimal. Because of this, this thermal tolerance. Critical thermal limits are deter- study aimed to determine the preferred temperatures, mined by increasing or decreasing the temperature thermal tolerance, thermal window width, oxygen progressively from the acclimation temperature until routine rate and aerobic scope through novel metho- physical disorganization occurs in response to the dology in M. tenellum kept under laboratory conditions. thermal stressor. Both responses frequently used to quantify ectotherms tolerance to extremely high or low MATERIALS AND METHODS temperatures and so determine organism’s resistance to different thermal phenomena and permit identify the Prawn collection, handling, and acclimation proce- temperature at which the first symptoms of stress dures appear without being damaging (Becker & Genoway, 1979; Paladino et al., 1980; Beitinger & Bennett, Juveniles of M. tenellum (n = 1000) collected from 2000). Chacahua coastal lagoon, Oaxaca (15°57’N, 97°31’W). Prawns transported to CIIDIR-IPN Oaxaca facilities; According to Pörtner (2010) and Sokolova et al. after that maintained in two 1000 L tanks filled with tap (2012), at the critical temperature, aerobic scope water, at room temperature, and with permanent disappears and transition to an anaerobic mechanism in aeration. From the second day, they fed daily ad libitum the pessimum range, followed by a progressive decline at 9 and 16 h with Camaronina® (35% crude protein). of cellular energy levels occurred. These processes Daily cleaning performed by siphoning all uneaten food explain why animals can only live for a very limited and feces. After 30 days of acclimation, all specimens time beyond this threshold. were transported in two 200 L tanks with permanent Fry (1947) proposed a polygon, also called area of aeration and plastic mesh to provide shelter, to the the thermal window, calculated from preferred tempe- Marine Biotechnology Laboratory of Centro de rature and the CTmax and CTmin limits of animals Investigación Científica y de Educación Superior de previously acclimated at different temperatures. The Ensenada (CICESE). There, specimens placed in a 2 m3 polygon is considered ecologically relevant because it reservoirs and then gradually acclimated to local fresh provides an indicator how organisms tolerate tap water by exchange of 10% per day. During this temperature changes. This area reported as °C2 can use time, water temperature always maintained at 26°C. as a comparative index of thermal tolerance among After seven days, the temperature increased to 28°C species (Eme & Bennet, 2009). This thermal window is with titanium 1000 W heaters. a useful criterion to understand not only thermal Thermal biology and respiratory metabolism in Macrobrachium tenellum 5 60