Relationship between diet and sex of offspring
Principal Investigator: ROBERT MICHAEL ROBERTS
Abstract: There is considerable controversy whether in mammals altering the quality or quantity of food eaten by the mother can bias the sex ratio of offspring born. In initial experiments we compared the sex ratio of pups from NIH Swiss and CF 1 outbred mice fed two nutritionally complete diets that differed in their content of fat. The first was low in total triglyceride but high in carbohydrate (LF, low fat diet), while the second provided 60% of the calories as lard (VHF, very high fat). The diets had no effect on either litter size or gestation length, but mothers on high fat produced many more sons than daughters and a striking proportion of male-biased litters, while the reverse was true on the low fat diet. The sex ratio skewing correlated with diet and was independent of maternal weight. Age was an important variable, however. Only mature mice provided sex ratios that were highly skewed by diet at first pregnancy. The first goal will be to generate information on the relationship between the nature and timing of the diet and sex ratio. The aims will be to; 1) follow sex ratios of pups when mice are provided the diets only for a limited period during the period preceding conception and during early pregnancy; 2) confirm the generality of the observations by testing several inbred strains of mouse with different genetic backgrounds with the long term goal of analyzing the genetic basis of the sex biasing phenomenon; 3) test whether increasing the amount of n-3 unsaturated fatty acids in the diet influences sex ratio of offspring, as has been suggested for humans; 4) determine whether reducing the caloric intake of mice on the VHF diet causes a downwards readjustment of the sex ratio of pups. A second goal will be to determine when the skewing in sex ratios in bred females occurs and to understand what mechanisms might be responsible. The experiments will show whether Y-sperm have some advantage over X-sperm in either reaching or fertilizing oocytes in the reproductive tract of VHF mice, and, likewise, whether X-sperm have some advantage in LF mice. We shall test whether conceptuses are selected according to sex after fertilization rather than before, and, if so, whether the selection process occurs prior to or subsequent to implantation. Finally, we shall examine whether the experimental diets cause changes in serum hormones, blood electrolytes and metabolites, and alterations in the reproductive tract environment in such a manner that conceptuses of one sex might have an in utero competitive advantage over the other. Our observations could have major implications for control of human fertility, provide a practical way of adjusting the sex of progeny for a range of laboratory and farm animals according to how they are fed, and lend further credence for the controversial existence of a process of sex allocation in mammals that depends on the availability and quality of food resources.
Funding Period: 2004-08-01 - 2009-05-31
more information: NIH RePORT
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Department of Biomedical Sciences, 440F Christopher S Bond Life Sciences Center, University of Missouri Columbia, 1201 Rollins Road, Columbia, MO 65211, USA
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Department of Animal Sciences, University of Missouri Columbia, Christopher S Bond Life Sciences Center, Columbia, Missouri 65211 7310, USA
Biol Reprod 77:599-604. 2007..Since males fed the VHF diet had neither more Y-sperm nor sired more sons than daughters, the dietary effects are manifested exclusively through the female...
- Effects of diets enriched in omega-3 and omega-6 polyunsaturated fatty acids on offspring sex-ratio and maternal behavior in miceEmily D Fountain
Department of Biomedical Sciences, University of Missouri Columbia, Columbia, Missouri 65211, USA
Biol Reprod 78:211-7. 2008..05). In conclusion, the N-3 diet had negative effects on murine fecundity and maternal behavior, whereas the N-6 diet favored birth of daughters...
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Department of Biomedical Sciences and Bond Life Sciences Center, University of Missouri, Columbia, MO 65211, USA
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Departments of Biomedical Sciences and Bond Life Sciences Center, University of Missouri, Columbia, MO 65211, USA
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Bond Life Sciences Center, University of Missouri, 263a Life Sciences Center, 1201 Rollins St, Columbia, MO 65211, USA
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Bond Life Sciences Center, University of Missouri, Columbia, Missouri 65211, USA
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Departments of Biomedical Sciences and Bond Life Sciences Center, University of Missouri, Columbia, MO, USA
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