Influence of High <i>Eimeria tenella</i> Immunization Dosages on Total Oocyst Output and Specific Antibodies Recognition Response in Hybrid Pullets (<i>Gallus gallus</i>)—A Pilot Study
Background: Two high primary-immunization doses of a wild-type <i>E. tenella</i> strain were assessed in healthy pullets (5K <i>versus</i> 10K sporulated oocysts/bird) to understand the effects of coccidia infection. Methods: Acquired immunity was evaluated following primary...
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| Main Authors: | , , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
MDPI AG
2025-01-01
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| Series: | Antibodies |
| Subjects: | |
| Online Access: | https://www.mdpi.com/2073-4468/14/1/9 |
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| Summary: | Background: Two high primary-immunization doses of a wild-type <i>E. tenella</i> strain were assessed in healthy pullets (5K <i>versus</i> 10K sporulated oocysts/bird) to understand the effects of coccidia infection. Methods: Acquired immunity was evaluated following primary immunization and two booster doses with the homologous strain. Total oocyst shedding, clinical signs, and viability of every bird/group after each immunization/booster were recorded. Indirect ELISA measured the time course of humoral responses from each immunization group against sporozoite and second-generation merozoite of <i>E. tenella</i>. Antigen pattern recognition on these two asexual zoite stages of <i>E. tenella</i> was analyzed using Western blotting with antibodies from each immunization program. Afterwards, antigen recognition of specific life-cycle stages was performed using individual pullet serums from the best immunization program. Results: A primary-immunization dose of 1 × 10<sup>4</sup> oocysts/bird reduced the oocyst output; however, all pullets exhibited severe clinical signs and low specific antibodies titers, with decreased polypeptide recognition on both <i>E. tenella</i> asexual zoite stages. In contrast, immunization with 5 × 10<sup>3</sup> oocysts/bird yielded the best outcomes regarding increased oocyst collection and early development of sterilizing immunity. After the first booster dosage, this group’s antisera revealed a strong pattern of specific antigen recognition on the two assayed <i>E. tenella</i> life-cycle stages. Conclusions: The <i>E. tenella</i>-specific antibodies from the 5 × 10<sup>3</sup> oocysts/bird immunization program can aid in passive immunization trials and further research to identify B-cell immunoprotective antigens, which could help in the development of a genetically modified anticoccidial vaccine. |
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| ISSN: | 2073-4468 |