Sperm morphometry is affected by increased inbreeding in the Retinta cattle breed: A molecular approach

Abstract

The effect of inbreeding depression on sperm motility is well documented, but its influence on sperm morphometry has been scarcely examined to date. Here, we combined the use of computer‐assisted sperm morphometry analysis (CASMA) with a SNP‐based genomic approach to determine and characterize the effect of inbreeding on the sperm shape of a highly inbred cattle population. We determined seven morphometric parameters on frozen‐thawed sperm samples of 57 Retinta bulls: length (L, µm), width (W, µm), area (A, µm2), perimeter (P, µm), ellipticity (ELI; L/W), elongation (L−W)/(L + W) and perimeter‐to‐area shape factor (p2a; P2/4 × π × A). The comparison of highly inbred (HI) and lowly inbreed (LI) individuals based on runs of homozygosity (ROH) inbreeding values (F ROH) showed no differences between groups. An additional two‐step unsupervised sperm subpopulation analysis based on morphometric parameters showed significant differences in the abundance of different sperm subpopulations between groups (p < 0.05). This analysis revealed that HI bulls harbored a higher percentage of narrow‐head sperm as opposed to the higher percentage of large‐ and round‐headed sperm detected in LI. A further genomic characterization revealed 23 regions differentially affected by inbreeding in both groups, detecting six genes (SPAG6, ARMC3, PARK7, VAMP3, DYNLRB2, and PHF7) previously related to different spermatogenesis‐associated processes.

Effect of the rob(1;29) translocation on the fertility of beef cattle reared under extensive conditions: A 30‐year retrospective study

“…Second, some individuals are more ‘resistant’ to the harmful effects of inbreeding on the phenotype (by harbouring a reduced depression load (Poyato‐Bonilla et al., 2020)), and therefore, they could remain in some herds despite their inbreeding values if their fertility is not affected. Finally, our previous studies evaluating the effect of inbreeding on the fertility of Retinta animals suggested that such decrease is associated with negative changes in sperm quality in bulls rather than an effect caused by the fertility of the cow (Dorado et al., 2017; Teran et al., 2021).…”

Morphometric assessment of cryopreserved livestock bull spermatozoa in the tropics

“…The morphometric analysis of the sperm head involves an assessment of size and shape and its relation to functionality (Valverde et al, 2016). Moreover, these parameters are linked to genetic factors, and the breed of the bull can influence results (Terán et al, 2021). Moreover, solutions in which sperm are suspended and processed can influence these variables and cause alterations in measurements depending on the semen extender used for the samples (Fernandes et al, 2021; Fernandez‐Novo et al, 2021).…”