Comparative analysis of spermatozoa of <i>Procambarus clarkii</i> (Girard, 1852) and <i>Cambaroides dauricus</i> (Pallas, 1772) (Decapoda: Astacidea: Cambaridae, Cambaroididae)

Abstract Procambarus clarkii (Girard, 1852) and Cambaroides dauricus (Pallas, 1772) are two economically significant edible crayfish species. Systematic comparative studies on the sperm of these two crayfish species remain scarce, which has restricted the exploration and utilization of their germplasm resources. We analyzed the sperms of the two crayfishes from three aspects: morphology, internal structure, and proteomics. The sperms of both species are disc-shaped, immotile, with arms extending outward from the nucleus, containing microtubule structures, lacking the 9 + 2 arrangement typical of flagella, and without mitochondria or centrosomes. The number of sperm arms in P. clarkii was usually 4, rarely 5, with spike protrusions on the acrosome, 0 to 6 with no spike protrusion on the acrosome in C. dauricus. Based on sperm proteomics studies, 61 differentially expressed proteins were quantified in the sperm of the two crayfishes. The expression levels of immune and stress-related proteins and ubiquitin-proteasome pathway-related proteins in P. clarkii were significantly higher than in C. dauricus, which suggests better stress resistance and fertilization-related functions of its sperm; the differential expression of LAMP1 protein implied the functional differentiation of acrosomes between the two species. We provided an important theoretical basis for crayfish germplasm improvement and sustainable development for the aquaculture industry.