Soapwort extract supplementation alters antioxidant status of serum, liver and heart tissues in growing Japanese quails reared under chronic intermittent cold stress

Antioxidant effect of dietary soapwort extract supplementation was studied in growing Japanese quails suffering from chronic intermittent cold stress. For this purpose, a total of ninety 15-d-old quails were divided into three groups with three replicates. Chronic intermittent cold stress was applied every night between 22.00 to 06.00 h; starting at 14 °C for the first week, and gradually weekly lowered to 8 °C. Three groups were fed with corn-soy based standard diets supplemented with 0, 50, and 100 ppm soapwort extract for four weeks. At the end of the study, three males and three females were slaughtered to determine total antioxidant and oxidant status of serum, malondialdehyde, glutathione, glutathione peroxidase activity, superoxide dismutase of liver and heart tissues. Although the dietary soapwort extract had no effect on serum total antioxidant capacity, it significantly lowered the total oxidant status of serum in cold stressed quails. Glutathione and superoxide dismutase enzyme activity of liver and heart tissues were similar among groups. While the dietary soapwort extract had no effect on glutathione peroxidase activity of the heart tissue, it significantly increased glutathione peroxidase activity in the liver tissue. In relation to the control group, malondialdehyde concentrations in the liver and heart tissues were significantly lower in soapwort extract groups. These data suggest that dietary soapwort extract could alleviate the detrimental effects of oxidative stress in growing Japanese quails exposed to cold stress. Malondialdehyde, glutathione peroxidase, saponin, total antioxidant status, total oxidant status Cold stress in animals shows a suppressive effect on the immune system (Hangalapura 2006). Animals under intense stress suffer from lipid peroxidation of the cell membranes; reactive oxygen species (ROS) such as hydrogen peroxide (H2O2), hydroxyl radical (HO-) and superoxide anion radical (O2) are formed, resulting in tissue damage (Kovacs 1996). The ROS are made in the mitochondria during normal metabolism and scavenging by cell antioxidant mechanisms such as glutathione (GSH), glutathione peroxidase (GSH-Px) and superoxide dismutase (SOD). However, under cold conditions or any stress conditions, reactive oxygen species are formed much more than the cell scavenging capacity, and so cell damage occurs (Berzinska-Slebodzinska 2001). It is advised that antioxidant and immune system enhancing feed supplements might alleviate the detrimental effects of cold stress (Sahin et al. 2002). Awareness of potential problems associated with the toxicological and carcinogenic effects of the use of synthetic antioxidant feed preservatives such as butylated hydroxytoluene (BHT) and butylated hydroxyanisole (BHA) has focused research efforts on identifying ACTA VET. BRNO 2017, 86: 159–165; https://doi.org/10.2754/avb201786020159 Address for correspondence: Prof. Dr. Bestami Dalkilic Department of Plant and Animal Production Vocational School of Technical Sciences University of Gaziantep, 27310, Gaziantep, Turkey Phone: +90 342 317 17 32 Fax: +90 342 360 11 70 E-mail: dalkilic@gantep.edu. tr http://actavet.vfu. cz/ natural alternatives for oxidation control (Kahl and Kappus 1993). Recently, research has focused on identification of plants with natural antioxidant activity. Among these plant compounds are saponins which have several beneficial effects such as antibacterial (Nabinejad 2013), anticarcinogenic (Xiao et al. 2009), hypocholesterolaemic, antiinflammatory, and antioxidant activities (Kucukkurt et al. 2011; Aslan et al. 2005). Yu et al. (2015) determined antioxidant effects of ginseng stem-leaf saponins with enhancing antioxidant systems and decreasing malondialdehyde concentrations of some lymphoid organs (bursa, spleen, and thymus) in chickens suffering from oxidative stress by intramuscular cyclophosphamide injection. Gypsophila spp. is a perennial plant (Caryophyllaceae family), called “soapwort” (“coven” in Turkish) as it contains triterpenoid saponins. The root is often used in making the Turkish halvah, for fixing the oils in the mixture or to form a unique texture of halvah with its foaming effect (Baytop 1984). Plant materials are vastly used in animals due to their antioxidant, antimicrobial, and carminative properties for activating the body’s defense systems against detrimental effects of stressful conditions. The aim of this study was to examine the antioxidant activity of soapwort extract in chronic intermittent cold stressed Japanese quails at a growing age. Materials and Methods The Institutional Animal Care and Use Committee procedures were approved by the local Ethics Committee of Firat University (FUHADEK number: 2015/07). A total of ninety 15-day-old Japanese quails (Coturnix coturnix Japonica) were divided into three experimental groups of 30 birds, each group including 10 male and 20 female quails with three replicates. The soapwort extract used in this study was in a powder form (BIOSAP40X, containing more than 40% triterpenoid saponins), and was provided by Biosaponeks Biotechnology R&D Ltd (Adana, Turkey). In the experiment, the presence and concentrations of the soapwort extract (SE) in diets were the main factors tested. One group was fed with standard diet (control group) and for the treatment groups, 50 (SE-50 group) and 100 ppm (SE-100 group) of soapwort extract were supplemented to the standard diets. The chemical composition of the soapwort extract used in the study is shown in Table 1. Corn-soy based basal diet was prepared to obtain requirements for quails according to the National Research Council and is presented in Table 2 (NRC 1994). Chemical composition of feed ingredients and soapwort extract were analysed according to the Association of Official Analytical Chemists (2000) procedures and crude fibre was determined by the methods of Crampton and Maynard (1983). The carbohydrate level in the soapwort extract was determined by the method of Lane and Eynon (1923). The metabolisable energy (ME, kcal/kg) was calculated according to Carpenter and Clegg (1956) = 53+38 B formula [B = (crude protein %) + (2.25) (ether extract %) + (1.1) (starch %) + (sugar %)]. The amount of saponin within the soapwort extract was determined using the method described by Lalitha et al. (1987). The feed and fresh water were provided for ad libitum. A photoperiod of 24 h/day was maintained. All birds were kept under standard laying cages with 10 birds per cage under the same environmental conditions. Every night, room temperature was gradually lowered to obtain chronic intermittently cold stress as given in Table 3. For the sake of the animals’ welfare, the temperature was lowered gradually because of the shocking effect of sudden hypothermia on young chicks. The experiment was continued for four weeks and ended when chicks were 43 days old. At the end of the study, three females and three males were randomly selected in each group and slaughtered by cutting the neck, and blood samples were collected during the slaughter process. Blood samples were immediately centrifuged at 2,500 × g for 5 min, and sera were collected. Liver and heart samples were then taken and kept at -20 °C until laboratory analyses. The total oxidant status (TOS) and the total antioxidant status (TAS) of serum samples were measured colorimetrically using a plate reader (ADVIA 2400, Siemens). The TOS was measured at a 540 nm wavelength using the TOS kit (ASSAY KIT, Catalogue number: RL0024 LOT: RL026, Rel assay diagnostics, Gaziantep, Turkey) and expressed in mmol H2O2 equivalent/l. The TAS was measured at a 660 nm wavelength using the TAS 160 Table 1. The chemical composition of the soapwort extract, (BIOSAP-40X).