5 Maternal gestational nutrition perturbs small RNA code in offspring sperm in sheep
L. Zhu A , N. Tillquist B , J. Shi C , Q. Chen C , K. Govoni B , S. Reed B , S. Zinn B and Z. Jiang AA School of Animal Science, AgCenter, Louisiana State University, Baton Rouge, LA, USA
B Department of Animal Science, University of Connecticut, Storrs, CT, USA
C School of Medicine, University of California, Riverside, CA, USA
Reproduction, Fertility and Development 34(2) 236-236 https://doi.org/10.1071/RDv34n2Ab5
Published: 7 December 2021
© 2022 The Author(s) (or their employer(s)). Published by CSIRO Publishing on behalf of the IETS
The environmental stress reprograms aspects of gametes and early embryo development to modify postnatal phenotype. These effects can even be “memorized” in the germline as epigenetic information and persist into adulthood and future generations. In livestock, inadequate maternal nutrition during gestation can have immediate and life-long negative effects on offspring growth. However, knowledge about how maternal restricted feeding or over-feeding during gestation affects reproductive efficiency in males and their long-term effects on offspring in domestic species is limited, and the mechanisms by which they do so remain unclear. In this study, we sought to test the effects of maternal gestational restricted- and over-nutrition on semen parameters and sperm epigenetics (small RNAs) in F1 generations. In the experimental design, multiparous Dorset ewes (F0; n = 48) were oestrus synchronised and bred with one of two genetically related Dorset rams. Pregnant ewes were fed using a control (100% National Research Council (NRC) requirements), restricted (60% NRC), or over-fed (140% NRC) diet beginning on Day 30 of gestation through parturition; the resultant offspring will be referred to as CON, RES, and OVER, respectively. After lambing, all ewes were fed to 100% NRC requirements for lactating ewes so that observed effects on offspring could be attributed to maternal gestational diet. F1 ram lambs were used for semen collection at 8 months of age (n = 3 per maternal diet). The same semen collection was used for both semen analysis and small RNA analysis. Initial semen analysis did not detect significant differences in semen characteristics (volume, pH, sperm concentration, and motility) between RES, OVER, and CON groups. Sperm samples of three F1 individuals (n = 3) from three diet treatments were used for small-RNA sequencing analysis. Our analytical workflow showed that small RNA profiles were strongly conserved across biological replicate samples in each treatment. Among all annotated small noncoding (snc)RNAs in sheep, the majority of small RNAs in sheep sperm were identified as microRNA (miRNA), tRNA-derived small RNA (tsRNA), rRNA-derived small RNA (rsRNA), and yRNA-derived small RNA (ysRNA). Surprisingly, both maternal gestational restricted- and over-nutrition induced marked changes in sperm small RNA composition in F1 offspring. Specifically, mitochondrial tRNAs showed an overall different tsRNA production pattern compared with that of genomic tsRNAs in response to restricted- and over-feeding. Detailed mapping data of rsRNA showed the specific loci of different rRNAs from which they were derived, and there were dramatic changes in expression levels and a marked shift of rsRNA populations due to poor maternal nutrition. Overall, both sperm small RNA composition and expression levels were significantly altered in responses to poor maternal gestational nutrition in sheep. The altered small RNA code could be essential in programming male reproduction and mediating induced epigenetic inheritance in sheep, which warrants further investigation.
