Testis-specific changes in gene expression of post-pubertal beef bulls divergent for residual feed intake and exposure to different pre-natal diets

Citation

Johnson, C., Fitzsimmons, C., Kovalchuk, I., Kastelic, J., Thundathil, J. (2020). Testis-specific changes in gene expression of post-pubertal beef bulls divergent for residual feed intake and exposure to different pre-natal diets, 60(12), 1491-1502. http://dx.doi.org/10.1071/AN19524

Plain language summary

Selection for a feed efficiency measure known as residual feed intake (RFI) and its impact on male reproductive development has had mixed reviews in the past. Our previous studies demonstrated earlier puberty, larger testes and greater percentage of progressively motile sperm in less efficient high-RFI bulls. More understanding of the biology underlying differences in the testes of high- and low-RFI bulls is needed. To determine the effect of RFI and pre-natal diet on the expression patterns of testicular genes, testicular tissue was studied from 25 bulls of high- or low-RFI which were fed either normal or low pre-natal nutrition from 30 to 150 days after conception. Of 19 218 expressed genes, 17 were expressed differently between bull of high- and low-RFI, with no differences in gene expression found as a result of pre-natal diet or the interaction of diet and RFI. These differences in gene expression may be affecting cell growth, proliferation and steroid metabolism. Selecting bulls for feed efficiency may have an affect on reproduction and fertility.

Abstract

© 2020 CSIRO.Context: Selection for residual feed intake (RFI) and its impact on male reproductive development has had mixed reviews in the past. Our previous studies demonstrated earlier puberty, larger testes and greater percentage of progressively motile sperm in high-RFI bulls. However, the molecular mechanisms within testes of bulls with varying RFI remain unclear. Aims: To determine the effect of RFI and pre-natal diet on the expression patterns of testicular genes and use this information to explain differences observed across RFI. Methods: The study included 25 purebred-Angus bulls with a genetic background of either high or low RFI and fed either normal or low pre-natal nutrition from 30 to 150 days post conception. After slaughter (17 months), testicular tissue was recovered, and RNA was extracted and sequenced. Key results: Of 19 218 expressed genes, 17 were differentially expressed for RFI (including PLCD1, INPP4B), with no differences being observed for pre-natal diet or diet × RFI interaction (false discovery rate) < 0.1%). KEGG pathway analysis indicated that differentially expressed genes were associated with inositol phosphate metabolism, and phosphatidylinositol signalling. On the basis of a candidate gene-expression study, IGF1R was upregulated in high-RFI bulls (P < 0.1). Conclusions: Increased expression of IGF1R and lowered PLCD1 and INPP4B expression could activate PI3K-Akt signalling responsible for cell growth, proliferation and steroid metabolism in high-RFI bulls. Implications: Selecting bulls for feed efficiency might affect molecular networks associated with reproduction and fertility.

Publication date

2020-07-01

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