Effects of tylosin, probiotic and lactulose on disaccharidase activities and intestinal short-chain fatty acids production of rats and rats administered with E. coli suspension

Abstract

The objective of this investigation was to study the effect of oral administration of tylosin, probiotic and lactulose on disaccharidase activities and short-chain fatty acids (SCFAs) concentrations in the intestinal contents of rats and rats administered with E.coli suspension. One hundred and fifty, three-week-old, male wistar rats were divided into two experiments with 75 rats each. In the experiment 1, the rats were reared in a conventional condition. The rats in the experment 2 were administered with 1 ml of E.coli (10x10x10x10x10x10x10x10 CFU/ml) suspension for 5 days prior to the experiment and reared in a conventional condition. There were 5 treatments with 15 rats in each experiment. The treatments were C:control (1 ml of water), T:tylosin tartrate solution (0.1 mg/ml), P:probiotic (50 mg/ml), L:lactulose (667 mg/1 ml) and PL:combination of P and L (50 mg of P/ml of L). All rats were given each treatment using feeding tube once daily for 14 days. The feed intake was measured everyday. At days 0, 7 and 14 of the experiment, the rats were weighed and 5 rats in each treatment were sacrificed. Blood samples were collected for examining the blood picture values (hematocrit, hemoglobin, and white blood cell). The intestinal contents were collected for SCFs determination using gas chromatography. Mucosal tissue samples from the proximal jejunum (PJ), the distal jijunum (DJ) and the ileum (I) were collected for the determination of disaccharidase activities by measuring the glucose production from disaccharides digestion. Those mucosal samples, caecum (CE) and colorectum (CR) were collected for the determination of total deoxyribonucleic acid (DNA) and ribonucleic acid (RNA) concentrations. The growth performance and blood picture values were not affected by the treatments in both experiments. In the experiment 1, P increased acetate concentrations (P<0.05) in the small intestinal contents of the rats while T lowered valerate concentration in the largeintestinal contents (P<0.05). L and PL increased maltase activities in the ileum (P<0.05). T, P, L and PL increased lactase activities in the DJ (P<0.05) while T and P increased lactase activities in the ileum (P<0.05). In the experiment 2, P increased acetate, propionate and butyrate (P<0.05) in the large intestinal contents while L increased propionate and butyrate (P<0.05). The treatments did not affect the disacchridase activities of the rats administered with E.coli suspension. In conclusion, the supplementation of tylosin, probiotic or lactulose did not promote the growth and changes in blood pictures of the rats and rats administered with E.coli suspension. The administration of tylosin, probiotic or lactulose improved maltase and lactase activities of the rats in the experiment 1 but did not affect disaccharidase activities of the rats administered with E.coli suspension. The major effects of the supplementation were on the SCFAs concentrations in the lower gut of the experimental rats. Probiotic, lactulose and probiotic combined with lactulose affected the SCFAs concentration in the large bowel contents of the rats administered with E.coli suspension. They increased acetate, propionate, butyrate and valerate concentrations. Tylosin decreased SCFAs concentrations in both experiments.