Comparative Analysis of Locally Developed Vaccines and Monensin Against Coccidiosis in Chicks

Abstract

Coccidiosis is a parasitic disease caused by Eimeria in chickens, a major cause of economic loss and serious threat to poultry industry. For control of coccidiosis synthetic drugs are widely used either in their feed or water. Excessive use of these drugs resulted in resistance of Eimeria strains and rendered it less effective, for this reason vaccines are developed which are highly effective and unique. In present study three types of egg adapted vaccines were prepared (i) Gametocyte (ii) Gametocyte sonicated (iii) Gametocyte inactive by formalin. Twelve hen's eggs (10 days old) were kept at 39 DC and 70% humidity in an incubator and candled for embryo status. At 12th day sporulated Eimeria oocyst were inoculated in egg with the help of a sterile syringe. On day 7 post inoculation, chorio-allantoic fluid was collected to harvest micro gametes and macrogametes. Gametocytes were purified by centrifugation (1500 rpm/5 minutes), washed twice with normal saline and stored at 4 DC. Ninety one day old birds were purchased and divided into 6 groups, each containing 5 birds and were kept in triplicates. Group 1 was vaccinated with Gametocytes, Group 2 with sonicated Gametocytes, Group 3 with Gametocytes inactivated by formalin, Group 4 with monensin medicated drug, Group 5 was Infected with Eimeria spp. and Group 6 was non Infected. On 14th day of age each bird was inoculated with Iml of 10,000 sporulated oocysts of Eimeria, no infection was given to Group-6. Monensin drug was given to medicated group 4 in feed 100mg/kg on 5th day post infection. 0.2 ml vaccine was given orally to group 1,2 and 3. Performance parameters such as body weight gain, feed consumed, feed conversion ratio (FeR), oocyst counts (OPG), bloody diarrhea, lesion score, mortality and survival rate, histopathology and biochemical analysis were checked. Weight gain and feed consumption was more in non-infected control group and in gametocyte vaccinated group, approximately similar results were shown by monensin medicated group while in other two vaccinated groups i.e. gametocyte sonicated and formalin inactivated gametocytes showed comparatively less significant results. Oocysts per gram rate was higher in infected non medicated non vaccinated control group while there was mild shedding in gametocyte vaccinated and monensin medicated group. There was no oocyst shedding in non-infected control group. Feed conversion ratio was higher in infected groups. Lower lesion score of zero was shown by infected-medicated and non-infected control group while the other two vaccinated groups (2 and 3) showed lesion score of +2 and + 1 respectively. Maximum lesion scor was observed in positive control group of +4. Maximum survival rate of 100% was shown by gametocyte vaccinated group, monensin medicated group and negative control group while poorest survival rate of 50% was shown by infected non medicated and non-vaccinated group. Formalin inactivated gametocyte group 2 and sonicated inactivated gametocyte group 3 showed 80% and 60% survival rates respectively. Serum biochemical parameters such as uric acid, albumin, creatinine AL T, ALP and AST were investigated in all groups. Serum biochemical analysis showed significant decrease in albumin and ALP concentrations and increase level of uric acid, AST, ALT and creatinine in infected non medicated non vaccinated, formaline inactivated gametocytes and sonicated gametocytes vaccinated groups. Less severe histopathological lesions were found in gametocyte vaccinated and Monensin medicated groups, mild to moderate lesions were found in gametocyte sonicated and gametocyte inactivated with formalin. More agglutination was recorded in gametocyte vaccinated group as compared to other two vaccinated groups. While no agglutination was observed in infected group. It is concluded from present work that among three egg adapted vaccines prepared i.e., gametocyte, gametocyte sonicated and gametocyte inactivated with formalin, gametocyte (pure) vaccines were significantly more effective than monensin medicated group (ionophore drug) as well as other two vaccinated groups.