Histomorphological damage in the small intestine of wami tilapia (oreochromis urolepis) (norman, 1922) exposed to microplastics remain long after depuration
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Date
2022
Journal Title
Journal ISSN
Volume Title
Publisher
MDPI
Abstract
The histopathological effects of microplastics (MPs) in the gastrointestinal tracts of fish
following long-term exposure and depuration are relatively understudied. This study investigated
histomorphological damage in the small intestine of Oreochromis urolepis larvae following 65 d
exposure to 38–45 μm of polyethylene microspheres (PE MPs) and after a recovery period of 60 d.
Larval fish were assigned to each treatment group (control, 1, 10 and 100 PE MPs), where ingestion
and degenerative changes in the small intestine were examined using a routine hematoxylin and eosin
staining technique. The results highlighted significant PE MPs ingestion and retention proportional to
exposure dose (χ 2 = 49.54; df = 2). Villi height and width and epithelial cell height were significantly
affected and differed between treatment groups. Indices of damage to the small intestine organ
(χ 2 = 47.37; df = 2; p < 0.05) and reaction patterns of villi, epithelial, goblet and cryptic glandular cells,
leucocytic infiltration and blood congestion revealed significant occurrence of alteration as PE MPs
exposure dose increased. After the recovery period, no PE MPs were observed, and villi height, width
and epithelial cells showed recovery with no significant difference between treatment groups. Organ
indices declined (χ 2 = 12; df = 2; p < 0.05) but remained significantly different between treatment
groups, largely due to leucocytic infiltration (χ 2 = 9.08; df = 2; p < 0.05). The study demonstrated that
microplastics induced small intestinal wall degeneration, but recovery in young fish occurred slowly.
The damage likely compromised its digestive function, which may affect growth and reproduction.
This requires further research.
Description
Journal Article
Keywords
Microplastic, Oreochromis urolepis, Ingestion, Retention, Depuration, Small intestine, Histo- morphology, Lesion indices