Domoic acid in California sea lion fetal fluids indicates continuous exposure to a neuroteratogen poses risks to mammals

Abstract

Domoic acid (DA) is a neuroexcitotoxic amino acid that is naturally produced by some species of marine diatoms during harmful algal blooms (HABs). The toxin is transferred through the food web from plantivorous fish and shellfish to marine mammals resulting in significant morbidity and mortality. Due to the timing and location of DA producing HABs, it is well documented that pregnant female California sea lions (CSL) are regularly exposed to DA through their diet thereby posing exposure risks to a neuroteratogen in developing fetuses. In the present study, fluids from 36 fetuses sampled from naturally exposed pregnant CSLs were examined for DA. Domoic acid was detected in 79% of amniotic fluid (n=24), 67% of allantoic fluid (n=9), 75% of urine (n=4), 41% of meconium (n=17) and 29% of stomach content (n=21) samples opportunistically collected from CSL fetuses. The distribution of DA in fetal samples indicates an increased prenatal exposure risk due to recirculation of DA in fetal fluids and continuous exposure to the developing brain. Introduction:Domoic acid (DA) is a potent glutaminergic excitatory neurotoxin that is naturally produced by some species of marine diatoms in the genus Pseudonitzschia (Bates, 2000;Berman and Murray, 1997). The toxin accumulates in planktivorous finfish and shellfish such as anchovies, sardines, clams, mussels and scallops resulting in trophic transfer to marine mammals and humans (

Developmental Neurotoxicity of Domoic Acid: Evidence for a Critical Window of Exposure

“…For Rebekah Petroff, who was not involved in the new study, the results are consistent with observations in rodents, 16 , 17 , 18 , 19 marine mammals, 20 , 21 and nonhuman primates. 22 , 23 Petroff, a postdoctoral fellow at the University of Michigan, has studied DomA neurotoxicity in adult crab-eating macaques after low-level exposure.…”

Detecting Neurodevelopmental Toxicity of Domoic Acid and Ochratoxin A Using Rat Fetal Neural Stem Cells

“…The data from this study show the reduction in the degree of differentiation of rNSC into all three type of cells and the reduction in axonal length of neurons in the presence of low non-cytotoxic concentration of DA (0.05 μM). Data from rodents and non-human primates have shown that non-cytotoxic low dose exposure to DA during early life was associated with behavioral, memory deficits, and/or structural changes in the brain [47,48,49,50,51,52]. This memory loss may be linked to a reduction and/or the abnormal differentiation of neural stem cells.…”

Stress-related and reproductive hormones in hair from three north Pacific otariid species: Steller sea lions, California sea lions and northern fur seals

“…Our sample size was small, and whilst we had suspected cases of DA exposure in the dam, we did not know what, if any, exposure the solitary pups may have had. A larger study is needed to explore the influence of DA exposure in utero ( Lefebvre et al , 2018 ) and measuring stress-related hormones in hair samples from California sea lions provides a novel method that may prove useful when assessing endocrine function in the dam or exposure to in utero stressors.…”