Mobility of Japanese quail spermatozoa and its relationship to egg fertility

Sperm mobility (SM) appears to be primary determinant of fertility in chicken and turkey. The aims of this study were to extend the concept to the Japanese quail by developing an assay to quantify SM, explaining the basis of SM using motility properties measured by CASA, and exploring the relationship between SM and egg fertility. The study was carried out in three stages: i) males (n = 20) and females (n = 20) were mated individually; ii) ejaculates were collected from 20 males, and SM was measured; iii) males (n = 20) and females (n = 20) were mated individually. In Stages I and III, data were collected for egg fertility, Sperm_OPVL and Holes_IPVL . In Stage II, SM assay was developed and assay conditions were defined: effect of sperm numbers on absorbance in Accudenz solution; effect of Accudenz concentration on sperm motility and mobility; effect of quail proctodeal gland foam extract and incubation temperature on SM at 37 and 41°C. The recorded absorbance of sperm movement was dependent on sperm numbers in the sperm suspension overlaying the Accudenz (p < .001). At 41°C, SM, progressively motile sperm, VCL, VSL and VAP were negatively affected by Accudenz concentration (p < .05). The effect of foam on SM and motility depended on an interaction between the concentration of foam extract and incubating temperature. Males were categorized into low, average and high SM phenotypes. These categories differed significantly (p < .001), but sperm motility and SM were not related to egg fertility. In conclusion, SM assay can be used to identify mobility phenotypes, but the poor relationship between SM and egg fertility indicates a need for further studies on interaction between the concentration of foam extract, incubating temperature, and in vivo sperm movement and egg fertilization success.