Temporal changes of ethoxyresorufin‐O‐deethylase (EROD) activities and lysosome accumulation in intestine of fish on chronic exposure to dietary benzo[a]pyrene: Linking EROD induction to cytological effects

Abstract

Temporal changes of intestinal and hepatic ethoxyresorufin-O-deethylase (EROD) activities and quantitative changes of secondary and tertiary (e.g., 2 degrees/3 degrees) lysosomes in enterocytes were compared for the juvenile grouper (Epinephelus coioides) on chronic exposure to foodborne benzo[a]pyrene (BaP) at two environmentally realistic levels (0.25 and 12.5 microg/g fish/d) over a four-week exposure and four-week depuration period. Intestinal EROD induction was rapid (within 3 d) and sustained in the BaP-exposed fish, while a fast recovery (within one week) was observed on withdrawal of BaP intake. A dose-response relationship was demonstrated between intestinal EROD activities and the levels of foodborne BaP. Conversely, hepatic EROD induction was weak and subsided rapidly in the exposed fish, signifying that hepatic EROD activity is not a good indicator of oral intake of BaP. Significant increase of 2 degrees/3 degrees lysosomes, as measured by Vv(lysosome, mucosa), was detected in young enterocytes of fish in the high-dosing group (12.5 microg/g fish/d) at exposure day 3 and persisted until recovery week 2. Importantly, intestinal EROD activity was significantly correlated to 2 degrees/3 degrees lysosome accumulation in enterocytes (r = 0.571, p < 0.001). These results further corroborate our earlier findings that induction of EROD activities in fish do not merely indicate exposure to BaP but also are correlated to harmful biological effects. We recommend the use of these two biochemical and cytological changes in intestines as specific biomarkers to indicate current and recent exposure of fish to BaP via oral intake.

Multigenerational effects of benzo[a]pyrene exposure on survival and developmental deformities in zebrafish larvae

“…Moreover, they evaluated developmental deformities by “visual inspection” at 36 hpf at which time point development (organogenesis) is still occurring. Other effects of dietary BaP exposures to fish have been investigated (Couillard et al, 2009; Roesijadi et al, 2009; Yuen and Au, 2006), but none of these studies investigated offspring development or multigenerational effects.…”

Polyaromatic hydrocarbons in aquafeeds, source, effects and potential implications for vitamin status of farmed fish species: a review

“…; VanVeld et al . ; Yuen & Au ). Further intestinal EROD activities are highest in the pyloric caeca and in the proximal half of the intestine (Vanveld et al .…”

Modulation of telomerase activity in fish muscle by biological and environmental factors

“…This concentration of foodborne B[a]P was chosen as it is environmentally realistic (Zhang et al, 2012), and has been found to (i) significantly increase muscle B[a]P body burden in juvenile areolated grouper (Epinephelus areolatus) (Wu et al, 2003) and (ii) inhibit growth in juvenile carnivorous fish (Epinephelus coioides) (Yuen et al, 2007). The detailed experimental steps were described by Yuen and Au (2006); Yuen et al (2007). After 1 month of B[a]P exposure, five fish were sampled randomly from both the solvent control and B[a]P treatment tanks.…”