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Vaccines

 

Quantization of Plasma D-xylose Concentration Following of Vaccination against Coccidiosis and Experimental Subclinical Coccidiosis Induced By Eimeria maxima in Broilers


Shojaei, S.Sh.R*, Nodeh,H.**, Teshfam, M**, Rahbari ,S.***Bokaie, S****
*Department of Parasitology, Faculty of Veterinary Medicine, Islamic Azad University, Karaj Campus, Karaj, IRAN, vetparasitologist@yahoo.com
**Department of Physiology and Pharmacology, Faculty of Veterinary Medicine, University of Tehran
***Department of Parasitology, Faculty of Veterinary Medicine, University of Tehran
****Department of Food Hygiene, Faculty of Veterinary Medicine, University of Tehran

Coccidiosis, particularly its subclinical form, which usually is not being promptly and correctly diagnosed, causes economic losses in broiler production. Each year, a significant amount of money is spent in its chemical prevention, but this is not always effective due to several causes, such as management problems, drug resistance, etc. The use of vaccination for the prevention of coccidiosis has been recently proposed, and different vaccines have been evaluated and compared. The intestinal D-xylose absorption test is a suitable method for studying intestinal mal-absorption in humans and animals, such as poultry. The main aim of this study was to evaluate the effects of vaccination against coccidiosis on the absorptive index by using the intestinal absorption test in broilers. A total number of 60 healthy Arbor Acres one-day-old broilers was purchased and equally divided into 6 experimental groups as follows: Group 1 –negative control with no vaccine and no challenge by E. maxima; Group 2 – 15-day-old birds were challenged with a suspension containing 50,000 sporulated oocysts of E. maxima, but no vaccinated; Group 3 – vaccinated at 4 days of age with Iracocc (a non-attenuated live vaccine) and not challenged; Group 4 – vaccinated at 4 days of age with Livacox T (a live attenuated vaccine) and not challenged; Group5 vaccinated with Livacox T and challenged with E. maxima; Group 6 – vaccinated with Iracocc and challenged with E. maxima. Seven days after challenge (at 21 days of age), 5 chicks were randomly chosen from each group, and after being submitted to 12 hour fasting, each chick received a solution of D-xylose at 5% by stomach tube. Blood samples were taken 30, 60, and 90 minutes after D-xylose administration, using heparinized microhematocrite tubes. Plasma D-xylose concentration was determined using the Modified Ebert’s Methods (Goodwin, 1984). The obtained results showed that the lowest plasma concentration of D-xylose belonged to the challenged group. However, no significant difference was observed between the negative control group and all vaccinated groups, including the group that was vaccinated and challenged with E. maxima. The results of this experiment indicate that concentration of plasma D-xylose in vaccinated broilers was not significantly reduced in comparison with normal broilers. On the other hand, it was shown that this concentration was significantly higher in all vaccinated groups as compared to the group that was challenged, but was not vaccinated. No significant difference was found between group 4 (vaccinated with Livacox and not challenged) and group 5 (vaccinated with Livacox and challenged) or group 2 (challenged and not vaccinated). The same results were obtained for the Iracocc-vaccinated groups. Therefore, it seems that both vaccines are not efficient, and that it is possible to use intestinal D-xylose absorption test to evaluate anticoccidial vaccines, in addition to parasitological and immunological evaluation. In fact, we recommend the use of these physiological experiments to better evaluate anti-coccidial vaccines, and we believe that this method can be used for evaluating broilers flocks in which subclinical coccidiosis is suspected.

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