ACCUMULATION OF IRON AND NICKEL IN TESTES AND EPIDIDYMIS OF BROILER RABBITS AFTER NICKEL PERORAL ADMINISTRATION

Journal of Microbiology, Biotechnology and Food Sciences Kalafova et al. 2012 : 2 (2) 548-555 REGULAR ARTICLE ACCUMULATION OF IRON AND NICKEL IN TESTES AND EPIDIDYMIS OF BROILER RABBITS AFTER NICKEL PERORAL ADMINISTRATION Anna Kalafova*1, Jaroslav Kovacik1, Marcela Capcarova1, Adriana Kolesarova1, Peter Massanyi1, Norbert Lukac1, Monika Schneidgenova1, Robert Stawarz2, Grzegorz Formicki2, Tomasz Laciak2 Address: 1Ing. Anna Kalafova, PhD. ,Slovak University of Agriculture, Faculty of Biotechnology and Food Sciences, Department of Animal Physiology, Trieda A. Hlinku 2, 949 76 Nitra, 2 Pedagogical University, Institute of Biology, Department of Zoology, Cracow, Poland * Corresponding author: e-mail: ABSTRACT This study reports the effect of dietary nickel (Ni) on the accumulation of Ni and iron (Fe) in testes and epididymis of rabbits. Broiler rabbits (Oryctolagus cuniculus) of experimental groups were fed a granular mixture with addition of various concentrations of Ni (E1 – 17.5 g NiCl2 per 100 kg of feed mixture, group E2 - 35.0 g NiCl2 per 100 kg of feed mixture). Group of rabbits withou Ni addition served as control (C). After the 90-days experimental period biological material (testes and epididymis) was taken from the animals. The samples were analyzed for concentration of Ni and Fe using the atomic absorption spectrophotometry (AAS) method. The concentrations of Fe and Ni in testes and epididymis in groups with dietary Ni supplement were not influenced and differences among the groups remained insignificant (P>0.05). Keywords: Nickel, iron, testes, epididymis, rabbits 548 JMBFS / Kalafova et al. 2012 : 2 (2) 548-555 INTRODUCTION Nickel (Ni) is a heavy metal present in parts of the environment. It is the fifth most widespread element on Earth. Ni (II) compounds are used in different industries and for producing everyday objects, also used in shipbuilding, chemical, electrochemical, and galvanizing industries. It is used for producing Ni-Cd batteries, stainless steel, bathroom fittings, coins, colourings, kitchenware, cutlery, surgical instruments, dental and orthopedic prostheses, artificial jewellery, and so forth. Thus, Ni exposure is a problem of the whole population and allergies to nickel are reported quite often (10% women, 1% men) (Prystowsky et al., 1979; Das et al., 2008). Although the toxicity and carcinogenicity of nickel compounds in humans and experimental animals are well demonstrated, the underlying mechanisms of their action remain unclear (Sunderman et al, 1985; Stohs and Bagchi, 1995). The most plausible mechanism that may be operative in vivo is the generation of reactive oxygen species (ROS), which may initiate lipid peroxidation (LPO), oxidative damage of critical macromolecules such as proteins or DNA, and cell damage or death. LPO constitutes a free radical oxidation process in which polyunsaturated fatty acids of the cell membrane decompose to yield, among others, highly reactive lipid hydroperoxides, H2O2, hydroxyl radicals, and malondialdehyde (MDA) (Pryor, 1985; Halliwell and Gutteridge, 1989). Effects on reproduction and essential trace metal (especially Fe ) metabolism have been reported at levels as low as 5 μg.g−1 in food or drinking water (0.2–0.4 mg.kg-1) but these findings have not always been corroborated (Outridge and Scheuhammer, 1993). Kalafova et al. (2011a, 2011b, 2011c, 2011d, 2012) reported that peroral administration of Ni or combination of Ni and Zn affect some production and metabolic parameters as well as the content of mineral elements in some organs of rabbits. The aim of this study was to investigate the effect of dietary Ni on the accumulation of Ni and Fe in testes and epididymis of rabbits. MATERIAL AND METHODS Animals In the present study, adult male rabbits (Oryctolagus cuniculus, Californian breed, broiler line) were used. Rabbits (n=15) were obtained from an experimental farm of the Animal Production Research Centre Nitra, Slovak Republic. Rabbits (age: 4 months, 549 JMBFS / Kalafova et al. 2012 : 2 (2) 548-555 weighing 3.5–4 kg) were housed in individual flat-deck wire cages (area 0.34 m2) under a constant photoperiod of 14h of day-light.The temperature (18–20◦C) and humidity (65 %) of the building were recorded continually using thermograph positioned at the same level as the cages. The animals were healthy and their condition was judged as good at the commencement of the experiment. In this animal study institutional and national guidelines for the care and use of animals were followed and all experimental procedures involving animals were approved by the State Veterinary and Food Institute of the Slovak Republic. Experimental design and diets Rabbits were randomly divided into 3 groups (n=5 in each group). Rabbits were fed with a granular feed mixture ad libitum (KKV1). The experimental groups (E1 and E2) received Ni addition in the diet for 90 days (Table 1). The group that received a diet without Ni served as a control group. Table 1 Design of experimental intervention Group Ni inclusion in g.100 kg-1 of FM C E1 E2 - 17.5 35.0 FM – Feed mixture, C – control group, E1,E2 – experimental groups Procedures The samples were analyzed for concentration of Ni and Fe using the atomic absorption spectrophotometry (AAS) method (wavelength for Ni 232.0 nm, Fe 248.3 nm). Biological material (testis and epididymis) was taken from animal organisms with chromo-nickel surgical instruments. Preparation samples were dried until dry mass was obtained. To obtain the dry mass, small pieces of tissue with the weight of 0.050 to about 1.000 g were placed on a Petri’s dish and put into the thermostat regulated dryer at 60◦C for 24h, next, the dryer temperature was set to105◦C. The samples were regularly weighted day by day until the loss of their mass was unnoticeable. Dried samples were mineralized by wet mineralization. In the process of wet mineralization all dry material of each sample was placed in separate mineralization tubes, dissolved by adding 2mL of concentrated HNO3-HClO4 mixture in the proportion 4:1 and heated in a thermostat digestion block at 120◦C for 90 min. The resulting 550 JMBFS / Kalafova et al. 2012 : 2 (2) 548-555 solution was diluted to 10 mL with demineralised water. All element concentrations are expressed on wet-weight basis in µg.kg-1. The recovery of the method was 96–98 % and the reproducibility was better than 1 %. Statistical analysis To compare the results the analysis of variance, one-way ANOVA test were applied to calculate basic statistic characteristics and to determine significant differences among the groups. Statistical software Sigma Plot 11.0 (Jandel, Corte Madera, USA) was used. Differences were compared for statistical significance at the level P<0.05. RESULTS AND DISCUSSION Concentration of Ni in testes and epididymis of rabbits The concentrations of Ni in testes and epididymis after dietary inclusion of Ni are presented in Figure 2. The analysis (...truncated)