The influence of feeding purple wheat with higher content of anthocyanins on antioxidant status and selected enzyme activity of animals

The influence of anthocyanins on antioxidant activity and liver function was measured in three different animal species (rats, chickens and fish). Purple Konini wheat with the total anthocyanin content (TAC) of 41.70 mg/kg was fed to the experimental groups of animals (rats n = 32; chickens n = 32; fish n = 20). The same numbers of animals (control groups) were fed common wheat with TAC of 24.95 mg/kg. At the end of the experiment, the animals were killed and blood and liver tissues were taken for biochemical analyses. The liver enzyme activities were measured in blood. Antioxidant activity in the liver tissue was measured using the DPPH (2,2-diphenyl1-picrylhydrazyl test), FR (Free Radicals method), FRAP (Ferric Reducing Antioxidant Power method), and ABTS (2,2’-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) test. Significantly higher values (P < 0.05) measured by the DPPH and FR methods were determined in the liver from rats fed Konini wheat. The chickens fed Konini wheat showed significantly different values using DPPH, FR and ABTS methods. No significant differences were found in hepatopancreases of fish. Animals fed Konini wheat showed a tendency to lower liver enzyme activities in general, but a significant difference was found only in gamma-glutamyl transferase activity in the chicken’s blood. Our results suggest that feeding a higher content of anthocyanins can improve the antioxidant activity and function of the liver tissue. Rats, chickens, fish, free radicals, radical scavenging activity Besides the contents of nutrients and toxic substances in rations, researchers lately increasingly focus on the biologically active substances with protective and preventive effects against the degenerative diseases and other health problems that may lead to the shortening of life (Ficco et al. 2014; Kaur et al. 2014). In recent years, much attention has been paid to researching a number of substances with antioxidant action, which include vitamins, microelements, and many other compounds naturally occurring in plants and producing positive effects both in human and animal nutrition (Abdel-Aal and Hucl 2003; Englmaierová et al. 2011; Suchý et al. 2014; Sun et al. 2014). Health benefits have been partly attributed to the unique phytochemicals present in the whole grain (Liu 2007). Flavonoids possess antioxidant properties against reactive oxygen species.Antiallergic, anti-inflammatory, and analgesic effects were also demonstrated, including the ability to affect nutrient transfer at the capillary level (Opletal and Skřivanová 2010). In crop species, the edible organs show large variations in colour. In the wheat grain, which is a staple food for humans and grain feed for animals, the colour is mainly due to natural classes of pigment: carotenoids and anthocyanins. Anthocyanins accumulate in the aleurone or pericarp of wheat and provide the blue, purple and red colours of the grain (Ficco et al. 2014). Anthocyanins could be the major compounds distinguishing purple wheat from other coloured wheats for their high antioxidant activity (Liu et al. 2010). It is well known that herbal anthocyanins are functioning as antioxidants and, in addition, they have antiACTA VET. BRNO 2016, 85: 371-376; doi:10.2754/avb201685040371 Address for correspondence: Eva Mrkvicová Department of Animal Nutrition and Forage Production Faculty of AgriSciences, Mendel University in Brno Zemědělská 1, 613 00 Brno, Czech Republic Phone: +420 545 133 174 Fax: fajmon@mendelu.cz http://actavet.vfu. cz/ bacterial and anti-carcinogenic effects (Liu et al. 2010; Varga et al. 2013). Correlation between the content of anthocyanins and antioxidant activity has been established. The highest correlation was found between the total reducing power and total anthocyanins (r = 0.97) (Mitic et al. 2014). Anthocyanins also have therapeutic effects against tissue inflammation, capillary fragility, cardiovascular diseases, cancer, hyperglycaemia, and oxidative liver damage in humans (Mazza 2000; Kähkönen and Heinonen 2003; Broncel et al. 2007; Giampieri et al. 2012; Hassellund et al. 2012). The influence of anthocyanins in food for human and animal consumption needs to be monitored. When Kirakosyan et al. (2015) fed rats with tart cherry, the highest concentration of anthocyanins was found in the liver. Therefore, increased antioxidant activity in this organ is expected. The aim of this study was to investigate the effect of feeding purple Konini wheat with a higher content of total anthocyanins on the antioxidant status and liver tissue function in different animal species. Materials and Methods Wheat and diets used in the experiment Purple Konini wheat with a higher total anthocyanin content (TAC) of 41.70 mg/kg was used for the experiment. For control groups, common Bohemia wheat with TAC of 24.95 mg/kg was used. The total anthocyanin content was determined spectrophotometrically, recalculated and expressed in the content of cyanidin-3-glucosid. The method described by Lee et al. (2005) was used for determination of TAC in wheat. The animals were fed wheat only. The nutrient content in the experimental diets is described in Table 1. Control wheat and Konini wheat were the only feed fed to the animals so as to eliminate possible influences of other antioxidants. The diets were fed to the rats, chickens and fishes. The content of crude protein in diets for chickens and rats was increased in the control feed using wheat gluten to be identical as in Konini wheat. Table 1. Content of nutrients in wheat diets (data are converted to 100% of dry matter). Crude ash Crude protein Crude fat Crude fibre Brutto energy % of dry matter MJ/kg Control group 1.79 16.98 1.61 2.39 17.56 Konini group 2.08 16.15 1.83 2.56 17.60 Experimental animals The experiment was carried out in three different animal species, chickens, rats, and fish representing three different models of animals (birds, mammals, fish) with a high percentage of cereals in the diet. The animal procedures were reviewed and approved by the Animal Care Committee of Mendel University in Brno. Animals were divided into two groups, control and experimental. Control groups were fed control wheat with a lower TAC (Bohemia) and experimental groups were fed Konini wheat with a higher TAC. Trial with rats: Selected male laboratory rats of the Wistar Albino strain (n = 64) at the age of 9 weeks were divided into two groups. Rats were marked by shaving off specific areas and kept in plastic boxes with 8 rats per box. The initial average live weight of rats was 259.06 ± 20.05 g. The values of room temperature (20–23 °C) and humidity (50–60%) were controlled. Lighting system was 16 h light and 8 h dark. The experimental group (n = 32) was fed milled wheat in pelleted form (100% purple Konini wheat). The control group (n = 32) was fed milled control wheat in pelleted form (100% common wheat with gluten) ad libitum. The dry matter of experimental diets was 89.1%. Body weight gains were followed at two-day intervals and the feed consumption was followed daily. The experiment continued for 23 days. At the age of 85 days the rats were anaesthetised using Isoflurane and bled. Blood samples were obtained by cardiac puncture using a test tube with heparin. The liver tissues were collected and frozen at -72 °C. Trial with chickens: Sixty four chickens of the hybrid combination COBB 500 with a wing sign with number were divided into two groups at the age of 39 days with the average live weight of 2,472.7 ± 180.48 g. They were bred in balance cages. Room temperature and humidity were controlled (mean values 21 °C and 60%, respectively). Lighting system was 16 h light and 8 h dark. The experimental group (n = 32) was fed a coarse meal of purple Konini wheat (100% wheat in the diet). The control group (n = 32) was fed a coarse meal of common wheat with gluten. The diets for 372