KUMARESAN, A.PRADEEP NAG B S2023-11-102023-11-102021https://krishikosh.egranth.ac.in/handle/1/5810200979The present study was undertaken to find out if modulation of micromilieu of oviductal cells alters the proportion of X- and Y- bearing spermatozoa binding to oviduct in cattle. As a prerequisite we standardized sperm oviduct explant binding model for cattle and also standardized a method for denudation of oviductal monolayer bound spermatozoa. oviductal cells were extruded from slaughterhouse derived non-luteal oviducts cultured in TCM-199 medium for 12 hours at 5% CO2 and 38.5°C to prepare oviduct explants. Sperm concentration (2 million), incubation timings (1 hr) and staining method Hoechst 33342 were standardized for obtaining optimal binding index. Using the standardized sperm oviduct model, the phenotypic and functional characteristics of oviductal cells bound and unbound sperm were assessed and found that membrane integrity, acrosome intactness and mitochondrial membrane potential were significantly (P<0.05) higher in bound sperm population in comparison with unbound sperm population. Sperm phenotype characteristics assessment indicated that highfertile bulls had significantly (P<0.05) higher oviduct explant binding index, membrane integrity, acrosomal intactness and mitochondrial membrane potential, and significantly (P<0.05) lower % DNA fragmentation index when compared to low-fertile bulls. In vivo experiment was conducted on cows (n=20) to study the effect of oral administration of calcium preparation on sex of the offspring; out of 6 calves, 5 calves were females. Based on the biochemical profile assessed in cows (n=6) three doses of calcium (0, 1 and 3 mM), magnesium (0, 1 and 3 mM) and glucose (0, 1 and 2 mM) were selected for in vitro modulation, Modulation of oviduct monolayer revealed that calcium at 1mM and 3mM facilitate 15.6 and 5.2 times, respectively more X chromosome bearing spermatozoa. In contrast, magnesium at 1mM and 3mM facilitated 22 and 37.4 times, respectively more Y chromosome bearing spermatozoa. However, we did not observe any clear deviation in sex ratio of bound spermatozoa. it was concluded that sperm phenotypes viz. sperm viability, acrosome intactness and high mitochondrial membrane potential are prerequisite characters to bind to oviduct. Further, and incorporation of calcium in incubation medium skewed sex ratio of oviductal cells bound spermatozoa towards X-bearing spermatozoa, while incorporation of magnesium skewed the sex ratio towards Y-bearing spermatozoa.EnglishThesis