11 June 2008

Omega-6 Intake Can Determine Offspring Gender

by Kate Melville

Researchers at the University of Missouri have established that maternal diet can influence the gender of offspring and that sheep fed a diet enriched with omega-6 fats have a significantly higher chance of giving birth to male offspring.

The study, carried out by researchers from the Division of Animal Sciences and reported in the journal Reproductive Biology and Endocrinology, explains how diet at the time of conception is a critical factor when it comes to influencing the sex of offspring. "Our study ruled out body condition, ewe weight, previous births, time of breeding, and likely dominance as reasons for the gender skewing," said lead researcher R. Michael Roberts. "Rather, it was the composition of the diet consumed in the time period around conception that was responsible for this sex-ratio effect."

Polyunsaturated fats, such as omega-3 and omega-6, are believed to have important biological effects in animals and humans, particularly in the context of inflammation, immunity and central nervous system signaling. The omega-6 fats used in this study were provided to the ewes one month prior to conception.

In animal groups with a small number of dominant males and a large number of females, it was believed that having male offspring would provide a genetic advantage to a very healthy, well fed female, while females consuming a poorer diet would have greater genetic success by giving birth to female offspring. Roberts' findings lend weight to this theory and he contends that this study is the first under controlled conditions to show that supplementing maternal diet, in this case by increasing omega-6 polyunsaturated fatty acid intake, can skew the sex ratio towards males in a farm species.

He adds that the findings will be important to the livestock industry. "Increasing the amount of fat in feed during the breeding period could provide a means of controlling the sex ratio of offspring born to a herd or flock," he noted.

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Source: Reproductive Biology and Endocrinology