An evaluation of gelatin as a diluent component for storage of chicken semen

This study was conducted using a gelatin-Beltsville Poultry Semen Extender (BPSE) mixture to determine whether or not gelatin aids in the preservation of chicken semen stored at temperatures of 4 to 12 C. Two experiments were conducted designed to determine 1) the optimum gelatin-extender ratio and 2) the optimum in vitro conditions (storage temperature, semen-gas ratio, stopper type, holding temperature, and semen-diluent ratio) for BPSE only and for the best gelatin-BPSE mixture as determined in Experiment 1. Varying the gelatin concentration in BPSE from 15 mg/ml to 30 mg/ml had no significant effect upon either fertility or hatchability. Varying the storage temperature, semen-air ratio, or stopper type had no significant effect upon fertility regardless of the presence or absence of gelatin. However, a significant interaction was noted between the stopper type and the diluent. Cooling semen diluted 1:1 with BPSE at a rate of 1 C/min to 10 C prior to storage and then transporting the post-stored semen at 10 C had a detrimental effect on fertility. Increasing the dilution rate above 1:2 had a significant negative effect upon fertility, with a significant interaction noted between the diluent and the semen-diluent ratio. When comparing BPSE only against the BPSE-gelatin mixture (30 mg/ml), the BPSE-gelatin mixture yielded significantly lower fertility in most instances and had no significant augmenting effect on fertility in those instances where it was not harmful. Therefore, under the in vitro conditions provided in this study, gelatin, in conjunction with BPSE, served no potentiating function in enhancement of fertility of stored chicken semen.