| Two experiments were conducted to determine the effect of oregano oil, nanometer zinc oxide and high concentration zinc oxide (ZnO) on growth performance, small intestinal morphology, bacterial population in colon and immune response of piglets with different weeks after weaning.Experiment 1 was conducted to investigate the effect of oregano oil, nanometer ZnO and high concentration ZnO on growth performance of just weaned piglets. 40 DLY (DurocxLandracexYorkshire) piglets (initially 8.8 + 0.88kg BW and 28-day-weaned) were randomly allotted to 5 treatment groups by weight and gender, each treatment had 4 replicates with 2 piglets per replicate; The trial was conducted for 28 days. The five dietary treatments were: (1) control with basal diet; (2) control + 200ppm oregano oil + 400ppm nanometer ZnO; (3) control + 250ppm oregano oil; (4) control + 400ppm nanometer ZnO; (5) control + 3000ppm ZnO. Every dietary treatment with the same basal diet hadn't antibiotics and high concentration Cu. The overall piglets were allowed ad libitum access to feed and water. Feed consumption, body weight and diarrhea were recorded. The results showed that the growth performance of just weaned piglets was improved by supplying oregano oil, nanometer ZnO, high ZnO and oregano oil + nanometer ZnO. Pigs fed 3000ppm ZnO had the greatest ADG. ADG of pigs fed 3000ppm ZnO, oregano oil + nanometer ZnO and nanometer ZnO was improved by 13.4% (P<0.01), 10.28%(P<0.01) and 7.5%(P<0.05), respectively. F/G of pigs fed oregano oil + nanometer ZnO was the lowest and reduced by 4.79%(P<0.05) compared with the control; pigs fed 3000ppm ZnO had the greatest F/G; pigs fed oregano oil and nanometer ZnO had a tendency to low F/G, but F/G was no significant difference among oregano oil, nanometer ZnO and the control. Supplying 3000ppm ZnO significantly increased ADFI by 17.69% (P0.01); ADFI of other treatments was no significant difference compared with the control. Diarrhea index of pigs fed 3000ppm ZnO was significantly reduced compared with the control and other treatments; diarrhea index was no significant difference among other treatments.Experiment 2 was conduced to evaluate the effect of supplying oregano oil, nanometer ZnO and high concentration ZnO on growth performance, intestinal mucous morphology, bacterial population in colon and immune ability of piglets with 3 weeks after weaning. 60 LY(Landrace Yorkshire) male piglets (initially 10+ 1.08kg BW and 21-day-weaned) were randomly allotted to 5 treatment groups by weight, 3 pigs were housed in per pen; the experimental period was 21 days. The dietary treatments were the same with trial 1. On d 14, four pigs with medium body weight in each treatment were selected for collecting blood sample from anterior vena and blood samples were used to determine serum IgG and Zn concentrations. At the termination of the trial, 3 piglets with medium body weight in per treatment were slaughtered to determine the mucous morphology of duodenal and jejunum and the population of E. coli and lactobacillus in colon. The results showed that the growth performance of piglets with 3 weeks after 21-day weaned was improved by supplementing aforementioned diets. The ADG of piglets fed oregano oil + nanometer ZnO was the greatest and increased by 8.92% (P0.01); ADG of pigs fed 3000ppm ZnO wasn't patently improved; there was no significant difference among ADG of other treatments. ADFI of piglets fed 3000ppm ZnO and oregano oil + nanometer ZnO were significantly improved (P<0.05); the difference of ADFI and F/G in other treatments was similar to the 28-day weaned piglets. Diarrhea index of piglets fed oregano oil + nanometer ZnO, 3000ppm ZnO and nanometer ZnO was significantly reduced. Oregano oil, nanometer ZnO and 3000ppm ZnO reduced the number of E. coli, but no significant difference was found compared with the control. Oregano oil 4+ nanometer ZnO reduced significantly the number of E. coli. There was no obvious effect on the number of lactobacillus in each treatment. Supplementing oregano oil + nanometer ZnO sig... |
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