Effect of exposure to dietary nivalenol on activity of enzymes involved in glutamine catabolism in the epithelium along the gastrointestinal tract of growing pigs

Abstract

Changes in the activity of enzymes involved in oxidative metabolism of glutamine, and in protein content, in the epithelial tissue along the gastrointestinal (GI) tract of growing pigs exposed to nivalenol (NIV) in the diet were investigated. The epithelial tissue was taken from the stomach, small intestine and colon of three groups of animals fed diets without NIV (control), with inclusion of 2.5 mg NIV/kg diet (low dose) and with inclusion of 5.0 mg NIV/kg diet (high dose). The activities of glutaminase, glutamate dehydrogenase, oxoglutarate dehydrogenase, isocitrate dehydrogenase and alanine aminotransferase were determined. In the control pigs the activities of oxoglutarate dehydrogenase and alanine aminotransferase were higher (P < 0.05) in the epithelium of the small intestine as compared with the stomach and colon, while there were no differences in the activities of glutaminase, glutamate dehydrogenase and isocitrate dehydrogenase. With increasing inclusion of NIV in the diet the activity of oxoglutarate dehydrogenase decreased (P < 0.05) in the epithelium of the small intestine and colon, and the activity of alanine aminotransferase tended (P = 0.07) to increase in the epithelium of the small intestine. The activities of glutaminase, glutamate dehydrogenase and isocitrate dehydrogenase remained unaffected by the inclusion of NIV in the diet. In the control pigs the protein content in the epithelium of the small intestine was higher (P < 0.05) than in the stomach and colon, while there were no effects of NIV inclusion in the diet on the protein content. It can be concluded from the present study that the epithelial tissue of the small intestine and colon of pigs exposed to a diet containing NIV will have a reduced enzymatic capacity to utilise alpha-ketoglutarate in the tricarboxylic acid cycle (TCA-cycle), suggesting an impaired energy supply to these organs.

Scientific Opinion on risks for animal and public health related to the presence of nivalenol in food and feed

“…Trenholm et al (1989) reported that pigs are the most sensitive farm animals to tricothecenes, with exposure associated with reduced feed intake and liveweight gain. In another study, a statistically significant decrease in the activity of oxoglutarate dehydrogenase was reported in small intestine and colon epithelium of 51 day-old male pigs (Landrace x Yorkshire) administered with a diet containing 2.5 or 5 mg nivalenol/kg for three weeks (Madej et al, 1999). The exposure to nivalenol via the feed, estimated to be 0.1 or 0.2 mg nivalenol/kg b.w.…”

Regulation of muscular glutamate metabolism by high‐protein diet in broiler chicks

“…The homogenate was used as the GA enzyme solution. GA activity was measured based on the methods of Madej et al . (1999), and the reaction product Glu was assayed at 340 nm, in accordance with the methods of Bernt and Bergmeyer (1974).…”

“…The GDH enzyme solution was prepared according to the methods of Madej et al (1999). The frozen muscle was homogenized in homogenate buffer (50 mmol/L triethanolamine/Cl, 1 mmol/L ethylenediaminetetraacetic acid (EDTA), 2 mmol/L magnesium chloride and 26 mmol/L mercaptoethanol, pH 7.5) using a high-speed homogenizer (Ultra-turrax T25 basic; Ikawerke, Staufen, Germany).…”

Regulation of taste-active components of meat by dietary leucine

“…GA activity was measured with the methods of Madej et al (1999), and measurement of the reaction product Glu was carried out following the methods of Bernt and Bergmeyer (1974). GS activity was measured with the methods of Arola et al (1981).…”

“…GDH solution was prepared using the methods of Madej et al (1999). The frozen muscle (0Á5 g) was homogenised on ice in 10 ml buffer (50 mM triethanolamine/Cl, 1 mM EDTA, 2 mM magnesium chloride and 26 mM mercaptoethanol, pH 7Á5) using a high-speed homogeniser (Ultraturrax T25 basic, IKA-WERKE).…”