Meeting Abstract
P2.119 Jan. 5 Parental Hypoxic Exposure Conveys Offspring Hypoxic Resistance in Larval Zebrafish HO, D.H.*; BURGGREN, W.W.; Univ. of North Texas, Denton; Univ. of North Texas, Denton dhh0005@unt.edu
Hypoxia is a teratogen that transiently alters gene expression of aquatic species resulting in reduced adult fitness as well as detrimental offspring phenotype. In light of evidence that toxin-specific resistance is afforded to the offspring of toxin-exposed adults, we investigated the effect of graduated hypoxic exposure of parents on their offspring�s subsequent resistance to hypoxic insult. Adult zebrafish (Danio rerio) were reared in normoxia (149 mmHg) or hypoxia (106 mmHg) for 4 weeks. During the 4 week period, pairs of zebrafish from the respective groups were bred, and eggs were collected at intervals of 1, 2, 3 and 4 weeks. Each treatment group was comprised of approximately 2 clutches. The embryos and larvae of hypoxic exposed parents (HP-1, HP-2, HP-3 and HP-4) and normoxic exposed parents (NP-1, NP-2, NP-3 and NP-4) were reared in normoxia for the remainder of the study. At developmental days (d) 6, 9, 12, 15, and 18, larvae were tested for time to loss of equilibrium (TLOE) in extreme hypoxia (35-38 mmHg). No difference in TLOE was observed between HP-1 and NP-1, nor were there differences among clutches within each group. However, HP-2 showed increased TLOE at d9, while HP-3 and HP-4 showed increased TLOE at d12 when compared to NP-2, NP-3 and NP-4, respectively (P�s < 0.01). Clutches within HP-2, HP-3 and HP-4 were significantly different at d9 and d12 (P�s < 0.05). Thus, hypoxic exposure (> 2 weeks) exaggerated the naturally-occurring differences in the ability of zebrafish to confer hypoxic resistance to their offspring. We conclude that parental hypoxic exposure in zebrafish induced an advantageous, clutch-dependent effect that allowed for increased hypoxia survivability in the subsequent generation.
