Parasite Prevalence and Bioaccumulation of Polycyclic Aromatic Hydrocarbons as Stressors in the Silver Catfish, Chrysichthys nigrodigitatus (Siluriformes: Claroteidae)
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Abstract
Description
The experiment explored the impacts of polycyclic aromatic hydrocarbons (PAHs) and the
prevalence of Aspidogastrea africanus (endoparasite) in Chrysichthys nigrodigitatus (host).
Host-parasite allotment of PAHs, histopathological analysis, and the oxidative status of parasite
and host were investigated. Oxidative status of fish and endoparasites were determined by
assessing the levels of Glutathion-S-Transferase (GST), Sodium Oxide Dismutase (SOD), and
Catalase (CAT). PAH concentrations were determined in the tissues of the host and parasite
using gas chromatograph coupled to flame ionization detector (GC-FID). Physico-chemical
parameters of water and sediment were assessed using a handheld multi-parameter probe (Horiba
Water Checker Model U-10). The parasitic prevalence in the examined fish was proportional to
length and weight of fish individuals. The parasites were more predominant among the length
and weight cohorts of the female fishes than the males. Higher induction of oxidative stress
enzymes in the intestine of the male C. nigrodigitatus than in the female, and the parasite can be
attributed to the higher levels PAH and partly absence of parasites to depurate the fish. A.
africanus shared the toxic burdens of chrysene, benzo(b)fluoranthene, dibenz(a,h)anthracene,
benzo(g,h,i)perylene, dibenzo(a,l)pyrene, dibenzo(a,i)pyrene and particularly indo(1.2,3-
cd)pyrene from the intestine of both sexes. In return, the endoparasite contributed the oxidative
stress in the intestine of the fish. Synergistic and antagonistic interactions between PAH
congeners and A. africanus on silver catfish, C.nigrodigitatus is evident in the current study. We
suggest mitigation of PAH-releasing anthropogenic activities around Lekki lagoon for the
protection of C. nigrodigitatus.
Keywords
QH Natural history, QH301 Biology, QL Zoology