Assessment of blood chemistry reference values for cultured sturgeon hybrids (Acipenser naccarii female 3 Acipenser baerii male) By P. Di Marco, A. Priori, M. G. Finoia, T. Petochi, A. Longobardi, V. Donadelli and G. Marino ISPRA Italian National Institute for Environmental Protection and Research, Rome, Italy Summary Blood chemistry profiles of cultured sturgeon hybrids Acipens- er naccarii female · Acipenser baerii male were assessed in order to acquire basic data for evaluating fish health status on-farm. Sixty healthy fish (11.0 ± 3.2 Kg weight; 117.8 ± 8.6 cm total length) were randomly captured from 600 m 3 concrete tanks and sampled from April to June. Blood samples were analyzed for the following 22 biochemical parameters using standard clinical methods: cortisol, glucose, lactate, non esterified fatty acids, triglycerides, cholesterol, albumin, creatinine, urea, total bilirubin, total protein, aspartate aminotransferase, alanine aminotransferase, alkaline phospha- tase, creatine phosphokinase, lactate dehydrogenase, calcium, phosphorus, magnesium, sodium, potassium and chloride. Biochemical values were found to be consistent with data from the parental species A. naccarii. Cortisol, cholesterol, albumin, urea, total bilirubin, CK, LDH and magnesium were signif- icantly affected by sampling time and the differences are probably related to sexual maturation of the fish. Blood chemistry analyses afforded an accurate evaluation of stur- geonsÕ health status, also providing information on their reproductive conditions. Evidence resulting from cortisol and lactate values indicated that pre-sampling operations, includ- ing capture and confinement of these large-sized fish, must be carefully managed in order to minimize handling stress. This study provides knowledge on blood chemistry of hybrid stur- geon A. naccarii · A. baerii and the results corroborate the validity of the test panel performed in evaluating the physi- ological functions of sturgeons. Reference values for 22 biochemical parameters were identified for the purpose of evaluating health and welfare in cultured sturgeons. Introduction Sturgeon aquaculture production is growing worldwide and captive populations are currently used for caviar production and hatchery propagation of endangered species (Bronzi et al., 1999, 2009; Pikitch et al., 2005; Raymakers, 2006). For this reason, the application of diagnostic tools suitable for stress and health evaluation in captivity is indispensable for sturgeon aquaculture development. The screening of blood chemistry parameters is regarded as a useful tool for assessing the health status of farmed animals (Stoskopf, 1993; Ivanc et al., 2005). Since aquaculture prac- tices may affect the physiological functions of cultured fish, periodic blood chemistry analyses provide an easy way of evaluating stress, metabolic disorders, reproductive dysfunc- tions and disease caused by environmental and husbandry conditions (Bayunova et al., 2002; Cech and Crocker, 2002; Lankford et al., 2003; Hamlin et al., 2007; Furne´ et al., 2009). However, reference values of the key biochemical parameters are still undefined for many species and the application of this method in clinical practice is hindered by lack of reference data. Recent studies on the assessment of normal blood chemistry values for some important species, including sturgeons high- lighted the importance of this knowledge as a prerequisite for evaluating health status in wild and cultured fish populations (Knowles et al., 2006; Manera and Britti, 2006; Shahsavani et al., 2008; Asadi et al., 2006 a and b; Shi et al., 2006; Fanouraki et al., 2007; Tavares-Dias and Moraes, 2007; Asadi et al., 2009; Shahsavani et al., 2010). The hybrid sturgeon Acipenser naccarii female · Acipenser baerii male has been experimentally investigated as a new species combination for aquaculture purposes in Italy (Arlati and Bronzi, 1995; Bronzi and Arlati, 2009). Due to its tolerance to warm temperatures and good zoo-technical performance, this hybrid is intensively farmed in Italy and included in the list of commercial species (G.U., 2008). More recently, commercial exploitation for caviar production has also been explored (Pazzaglia and Giovannini, 2009). Blood chemistry data for the hybrid sturgeon A. naccarii · A. baerii are lacking and very little information is available on the parental species (Maxime et al., 1995; Cataldi et al., 1998; Di Marco et al., 1999; Martı´nez-A ´ lvarez et al., 2002; Hamlin et al., 2008). The aim of the present study was to acquire blood chemistry data for the hybrid sturgeon and to provide reference intervals for the future monitoring of its health and welfare status in rearing conditions. In addition, the biochemical values assessed were compared and discussed with the latest literature data reported for other sturgeons, focusing in particular on the influence of aquacul- ture conditions on biochemical parameters and physiological functions. Materials and methods Fish husbandry Six-year-old healthy sturgeon hybrids A. naccarii female · A. baerii male (n = 60; 11.0 ± 3.2 Kg weight; 117.8 ± 8.6 cm total length) were used in this study. Fish were reared from 2005 to 2009 in a small experimen- tally constructed wetland located on a commercial fish farm (Ittica Spineto, Falerone, AP, Central Italy). Fish were kept in 600 m 3 concrete tanks supplied with freshwater pumped from the Tenna river at a rate of 15–20 L s )1 . Initial stocking densities were 2.0 and 4.3 kg m )3 . Growth performance and J. Appl. Ichthyol. 27 (2011), 584–590 Ó 2011 Blackwell Verlag, Berlin ISSN 0175–8659 Received: July 31, 2010 Accepted: December 3, 2010 doi: 10.1111/j.1439-0426.2011.01713.x U.S. Copyright Clearance Centre Code Statement: 0175–8659/2011/2702–0584$15.00/0 Applied Ichthyology Journal of