QUANTITATIVE-DETERMINATION OF SPERMATOZOA PENETRATION OF THE PERIVITELLINE LAYER OF THE HENS OVUM AS ASSESSED ON OVIPOSITED EGGS

A technique was developed to assess the number of cock spermatozoa pen etrating the perivitelline layer (PL) in oviposited eggs in vivo. Two trials were conducted to test this technique and to establish correlat ion values between fertility and sperm penetration (SP). First, three Athens Canadian Randombred males, previously tested as having high fer tility (100%), were each housed with seven hens. Sperm penetration was determined from eggs laid over a 3-d period (n = 41) with the mean nu mber of spermatozoa penetrating the PL overlying the germinal disc (GD ; 1.35 mm(2) area) and nongerminal disc (NGD) areas being 162.8 and 8. 4, respectively. Following removal of the males, SP was monitored to e stablish its duration with an average of 4.6 eggs analyzed per male pe r day. Mean sperm penetration during this period declined from 167.0 t o .2 and from 9.2 to 0 for the GD and NGD regions, respectively. The m ean duration of SP was 15.7 and 11.3 d for the GD and NGD FL, respecti vely. The duration of fertility was also established to be 14.0 d. The re was a positive correlation between sperm penetration of the GD PL a nd fertility from eggs laid by naturally mated hens (r = .89, P < .000 1). In the second trial, three groups (1, 2, or 3) of 16 hens (35 wk o f age) each were artificially inseminated weekly for 4 consecutive wk with either 100, 50, or 25 million sperm/50 mu L, respectively. Insemi nations were repeated weekly for 12 consecutive wk. Mean values were o btained from each of three 4-wk periods and used as replicates. Mean S P values from the GD PL for Groups 1, 2, and 3 were 40.2, 19.5, and 14 .1, with fertility values of 95.8, 92.4, and 83.3%, respectively. Each replicate mean was obtained from similar to 24 eggs per group per day postinsemination. A significant correlation between SP of the GD PL a nd fertility (r = .90, P < .0001) was established using artificial ins emination of hens.