Nanotechnology-based selection of boar spermatozoa: growth development and health assessments of produced offspring

The heterogeneous population of spermatozoa within the semen ejaculate influences the sire fertility. The current design of magnetic nanoparticle conjugates allows for selective targeting and removal of non-viable spermatozoa within the semen ejaculate. However, the safe application of this process, termed as nanoselection or nanopurification in previous studies, in food animal production and toxicity concerns has yet to be explored. Here, we assessed the fertility potential of nanoselected boar spermatozoa and the subsequent post-natal growth and health characteristics of resulting offspring. Semen doses were harvested from three fertile boars (n =4 doses per boar) and split in two groups (2 doses/boar). Six semen doses (2 per boar)) were subjected to the targeted depletion of acrosome membrane damaged and apoptotic spermatozoa (nanoselected). Meanwhile, the remaining semen doses (n = 6) were maintained in the shipping Styrofoam box (control). The motility characteristics of both control and nanoselected spermatozoa were evaluated before and after nanoselection, followed by their use for double inseminations of six estrus synchronized gilts (2 doses/boar/gilt; 3 gilts /control or nanoselected). In comparison to the controls, the computer-assisted sperm analyzer (Hamilton-Thorne) revealed greater motion characteristics of nanoselected spermatozoa, with a significantly higher proportion of progressive spermatozoa and straightness (P < 0.05). The fertility potential of nanoselected spermatozoa was not compromised, and produced offspring showed growth rates and weight gains at market that were comparable to their counterparts born from control spermatozoa (P > 0.05). Various developmental and health parameters of produced offspring such as hepatic cytochrome P450 enzyme activities, blood glucose and immunoglobulin G concentrations, hematocrit, and white blood cell proportions were similar between and across all pigs (control and nanoselected). In addition, reproductive tracts of females born from nanoselected spermatozoa showed no indication of impaired fertility potential, although a significant shortened uterine horn length was measured (56.3 +/- 2.6 cm vs. 64.4 +/- 2.2 cm in the control group, P = 0.04). In conclusion, findings revealed no obvious perturbations of sperm function following nanoselection, while post-natal growth, development, or health data of derived offspring suggest absence of inflicted sub-lethal toxicities attributable to sperm nanoselection. This study supports the safe use of the proposed nanotechnology-based selection for effective semen handling in terminal line swine production systems.