The effect of broccoli in diet on the cytochrome P450 activities of tilapia fish (Oreochromis niloticus) during phenol exposure Jorge Davila a , L. Moises Marcial-Martinez b , Maria Teresa Viana b , Rafael Vazquez-Duhalt c, ⁎ a Centro de Investigación Científica y Educación Superior de Ensenada, CICESE, Ensenada BC, Mexico b Instituto de Investigaciones Oceanológicas, Universidad Autónoma de Baja, California, Mexico c Instituto de Biotecnología, Universidad Nacional Autónoma de México, Av. Universidad 2001, Col. Chamilpa, Cuernavaca, Morelos 62250, Mexico abstract article info Article history: Received 16 November 2009 Received in revised form 23 February 2010 Accepted 23 March 2010 Keywords: Aquaculture Chemoprotection Cytochrome P450 Fish Phenol Pollution Aquaculture is the fastest growing animal food-producing sector and represents around 40% of global fish production. Doubtless, aquaculture will be soon the main world source of marine and freshwater food, over the capture fishery. Water pollution is a main concern for production and represents a public health risk. Cruciferous vegetables, as broccoli, have been reported to have a chemoprotection capacity against the effect of pollutants on different organisms. Broccoli and its phytochemicals are able to modulate the cytochrome P450 enzymes (CYP) which are involved in the xenobiotic metabolism. In this work, the effect of a broccoli-rich diet on different cytochromes P450 activities in liver from tilapia juveniles exposed to phenol was determined. Activities on phenacetin, chlorzoxazone, tolbutamide, mephenytoin, dextromethorphan, and testosterone, were monitored in tilapia liver extracts from fish fed with and without enriched broccoli diets, before and after phenol exposure. Fish were fed with broccoli and control diets during 30 days prior to phenol exposure at two sub-lethal concentrations of phenol (2 and 20 mg L -1 ), then the profile of CYP activities was determined at 0, 12 and 24 h after phenol addition. Before phenol addition fish fed with broccoli-rich diet showed a significant induction of phenacetin and tolbutamide activities when compared with liver extracts from fish fed with control diet. After phenol exposure a clear and steady induction of the dextromethorphan and mephenytoin activities were detected. In spite of the fact that substrates are not specific for each CYP, the increase of activity on dextromethorphan could represent the first report of a hepatic CYP2D6 induction by the presence of a xenobiotic. In addition, phenol exposure through diet was evaluated. Consistently with the previous experiments, phenacetin and chlorzoxazone showed higher activities while dextromethorphan and testosterone activities were lower in the liver extract from fish fed with broccoli than in control fish. Interestingly, tolbutamide activity was significantly higher in fish fed with broccoli than these observed in the controls, while mephenytoin showed 8-times higher activity in fish fed with control diet than those fed with broccoli enriched diet. The role of cytochrome P450 enzymes in the xenobiotic metabolism and the potential use of designed diets, containing chemoprotectors, to contend against pollutant effects on cultivated fish are discussed. © 2010 Elsevier B.V. All rights reserved. 1. Introduction Capture fisheries and aquaculture supplied the world with about 120 million tons of food fish. According to the Food and Agriculture Organization of the United Nations (FAO, 2007), 47% of global fish stocks are fully exploited, thus offering no reasonable expectations for further expansion, and another 18% are reported as overexploited. On the other hand, United Nations Environment Program (UNEP) estimated in 2002 that the 72% of the world's marine fish stocks were being harvested faster than they could reproduce (UNEP, 2004). On the opposite, aquaculture continues to be the fastest growing animal food-producing sector and represent around the 40% of global fish production (FAO, 2007). Doubtless, aquaculture will be soon the main world source of marine and freshwater food, over the capture fishery. Water quality is a main issue for aquaculture, because most of the farms are placed inland or on the seashore where anthropogenic activities impact the quality of water. Urban, agricultural and industrial activities, close to the farm facilities, release xenobiotic compounds that may pollute the aquaculture water source. Schwar- zenbach et al. (2006) reported that about 300 million tons of synthetic compounds seep annually into water systems (rivers, lakes and sea). Xenobiotics are potentially harmful to fish by inducing tissues damage in gill, kidney and liver (Ahmad et al., 2004), growth retardation (Gad and Saad, 2008), genotoxicity (Aas et al., 2000), reproductive disturbances (Maradonna et al., 2004), tissue bioaccumulation (Rice et al., 2000; Hellou and Leonard, 2004), and death (Arinç et al., 2000). Phenolic compounds are widely present in environment and represent one of the most common polluting chemicals (Roche and Aquaculture 304 (2010) 58–65 ⁎ Corresponding author. Tel.: +52 777 329 1655; fax: +52 777 317 2388. E-mail address: vazqduh@ibt.unam.mx (R. Vazquez-Duhalt). 0044-8486/$ – see front matter © 2010 Elsevier B.V. All rights reserved. doi:10.1016/j.aquaculture.2010.03.020 Contents lists available at ScienceDirect Aquaculture journal homepage: www.elsevier.com/locate/aqua-online