Abstract

HERNANDEZ LOPEZ, Dulce Janet; ULLOA ARVIZU, Raúl; VAZQUEZ PELAEZ, Carlos Gustavo  and  TAPIA PEREZ, Graciela Guadalupe. Effect of consanguinity and selection on the components of a productive index, in mice under close mating. Rev. mex. de cienc. pecuarias [online]. 2023, vol.14, n.1, pp.23-38.  Epub Mar 24, 2023. ISSN 2448-6698.  https://doi.org/10.22319/rmcp.v14i1.6073.

In order to examine the influence of inbreeding depression on some productive characteristics of the laboratory mouse, 871 records were reanalyzed, which were from 20 generations in a line with narrow inbred crossing with selection for a productive index (WOFW) comparing with a line without selection, with inbred crossing (n= 135). Inbreeding coefficients (F) were calculated for each generation. In all the components of the index (reproductive life, fertile postpartum estruses and litter size), the two lines were compared, in the 15 available generations of the non-selected one, by the least squares method, grouping every five generations. The selected one was analyzed in the 20 generations for intergenerational differences with the same method. Inbreeding depression was estimated in all generations with a linear regression of consanguinity (expressed in 10 %) in all components. A significant difference (P<0.01) was observed between lines in the variables analyzed. The fertile postpartum estruses of the selected line remained constant, there was a decrease of 0.331 in the non-selected one (P<0.01). The productive index remained stable (increased 0.071) in the selected one, in the non-selected one it decreased (0.39) until disappearing (G15). Inbreeding depression impacted the reproductive life of both, decreased 4.741 d in the selected one vs 7.718 d in the non-selected one (P<0.01). In the non-selected one, it affected mortality at weaning and estrous cycle, the selection to the index counteracted that impact, probably due to the selection of genes that favor the gonadal development of mice.

Keywords : Mice; Selection; Reproductive life; Number of estruses; Inbreeding depression.

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