Reduced auditory acuity in rat pups from excess and deficient omega-3 fatty acid consumption by the mother

Abstract

Consumption of the nutrients omega-3 fatty acids (ω-3 FA) during pregnancy and lactation is considered beneficial to fetal and infant development. It may also reduce the incidence and severity of preterm births by prolonging gestational length. However several recent human and animal studies have reported that over-supplementation with ω-3 FA, especially in the form of fish oil, can have adverse effects on fetal and infant development and the auditory brainstem response (ABR). Our goal was to assess further the effects of ω-3 FA excess and deficiency during pregnancy and lactation on the offspring's auditory acuity as evidenced by their ABR thresholds. Female Wistar rats were given diets that were either deficient, adequate (control) or excess in ω-3 FA from day 1 of pregnancy through lactation. The offspring were ABR-tested at the postnatal age of 24 days. The rat pups in the Excess treatment condition had significantly elevated (worse) ABR thresholds, postnatal growth restriction, and a trend for increased postnatal mortality in comparison to the Control group. The Deficient group was intermediate. In conclusion, excess or deficient amounts of ω-3 FA during pregnancy and lactation in the laboratory rat adversely affected the offspring's auditory acuity. Postnatal thriving was also adversely affected. Consuming or administering large or inadequate amounts of ω-3 FA during pregnancy and lactation seems inadvisable because of the potential for adverse effects on infant development.

Repeated antenatal corticosteroid treatments adversely affect neural transmission time and auditory thresholds in laboratory rats

“…Because of limited financial resources and the principle of reducing animal usage [78], the CON group was borrowed from a concurrent study in our laboratory [16-18]. The CON group consisted of n=23 litters.…”

“…Imbalances in the number of males and females within each litter were dictated by which offspring survived until the time of ABR testing. Pups were ABR-tested on PND 24 to simulate prior ABR developmental toxicology studies [16-18]. The rat ABR is well-developed by PND 24 [21].…”

The Effects of Maternal Dietary Docosahexaenoic Acid Intake on Rat Pup Myelin and the Auditory Startle Response

“…Longer auditory conduction times, indicating slower conduction through the brainstem auditory pathway, can result from structural damage or delayed development [24] . We [25,26] and Church et al [27] previously reported that auditory brainstem conduction times were significantly longer in the offspring of rats fed high levels of DHA or fish oil during pregnancy and lactation. Since conduction time is strongly associated with the degree of myelination of fibers within the auditory tracts [28] , the negative effects of high levels of dietary DHA on auditory brainstem responses may be mediated through effects on myelin.…”

“…The higher levels of maternal dietary DHA were associated with longer auditory brainstem conduction times [25,26] , and with later postnatal appearance of the auditory startle reflex [25,33] . Church et al [27] also reported that auditory brainstem conduction times were significantly longer in offspring of dams fed diets high in n3 fatty acids. These studies suggest that high levels of maternal DHA during pregnancy and/or lactation may exert negative effects on central neural system development, potentially through effects on myelin.…”

Influence d’une supplémentation en omégas 3 au cours de la grossesse

“…Des effets négatifs ont aussi été observés chez le rat en cas d'excès d'apport d'omégas 3 avec une altération de l'acuité auditive ainsi qu'un infléchissement de la croissance postnatale [27]. Wakefield et al ont récemment émis l'hypothèse d'un effet tératogène chez la souris lorsque la supplémentation en oméga 3 est réalisée pendant la période d'embryogenèse [28].…”