Abstract
Aim: Microplastics (MPs) are pervasive pollutants in the environment, raising concerns regarding their implications for both wildlife and human health. This study aimed to thoroughly investigate the effects of MPs exposure on chicken embryos, focusing particularly on alterations in the immune system and key biochemical markers.
Methods: The study extended from June to December 2023.Three groups, each comprising 30 eggs, were utilized in the study. These groups were subjected to increasing doses of MPs: Group C (control), group A (150µg/ml), and group B (300µg/ml). After 48 hours of incubation, eggs in groups A and B received an injection of 0.3 ml of the MPs solution, while eggs in the control group (group C) were injected with 0.3 ml of saline solution. Histopathological changes were assessed using hematoxylin and eosin (H&E) staining, while the biochemical properties of amniotic fluid were analyzed photometrically. Additionally, the expression of immune genes (AvBD9, AvBD10, and IL8L2) was evaluated through quantitative PCR.
Results: Marked changes in biochemical markers, such as urea, creatinine, alkaline phosphatase (ALP), aspartate aminotransferase (AST), and alanine aminotransferase (ALT), were observed in the amniotic fluid of groups treated with MPs compared to the control. Histological examinations revealed noticeable alterations in the caecal tonsil and bursa of Fabricius following MPs exposure, characterized by disruptions in cellular structures and variations in lymphocyte counts. Furthermore, a notable decrease in the expression of immunity genes, namely AvBD9, AvBD10, and IL6, was observed in the MPs-treated groups compared to the control.

Conclusion: These findings highlight the necessity for comprehensive risk assessments and safety guidelines regarding MPs exposure, considering its potential impacts, which include significant biochemical alterations, histopathological changes in lymphoid organs, and disruptions in immune response.