Sperm proteome and sperm parameters of captive Amazon squirrel monkeys (Saimiri collinsi Osgood, 1916) during the non-fatted and fatted condition

The aims of this work were (1) to characterize the proteome profile of Saimiri collinsi (Amazon squirrel monkey) sperm, and (2) to evaluate if there are meaningful differences in sperm quality and sperm protein landscape during the non-fatted and fatted conditions of the animals. Semen of adult males (n=4) was collected by electroejaculation and diluted in ACP-118® extender. Sperm concentration, motility, vigor, plasma membrane integrity and functionality, and sperm morphology were evaluated. Sperm proteome was characterized by mass spectrometry. The non-fatted and fatted conditions were defined according to the fattening index. There were increases in seminal volume, pH, and sperm motility of S. collinisi during the fatted in comparison with the non-fatted condition (p < 0.05). Animals in the fatted condition had greater body mass (909 ± 23.98 g) in comparison with the non-fatted condition (818.8 ± 5.97 g, p = 0.0001). There were 1161 proteins identified in the sperm of the monkeys. Thirty-seven proteins were upregulated (p < 0.05) in non-fatted condition (such as coiled-coil domain-containing protein 105, protein kinase C alpha type isoform X1, pyruvate dehydrogenase protein X component – mitochondrial and heat shock 70 kDa protein 1-like) and they were involved in cellular and metabolic processes, catalytic activity and binding. Twenty-eight sperm proteins proteins were upregulated (p < 0.05) in fatted condition (such as Cytochrome b-c1 complex subunit 2, mitochondrial; calcium-binding mitochondrial carrier protein SCaMC-1-like; heat shock 70 kDa protein 13, and izumo sperm-egg fusion protein 1), participating in cellular processes, metabolic processes, and localization, binding, catalytic activity, ATP-dependent activity, and transport activity. Functional annotations of sperm proteins upregulated in non-fatted condition were described as hydrogen ion transport, chaperone, cilium, flagellum, and cell projection. In in fatted conditions, such annotations were described as fertilization, spermatogenesis and transport, chaperone, and motor protein. The present study brings an unprecedent contribution to our understanding about the reproductive biology of adult Saimiri collinsi. It also provides support for conservation and development of assisted reproductive technologies for Neotropical primates.