The Effect of Age on Spermatological Properties in Rainbow Trout (Oncorhynchus mykiss W., 1792)


Abstract: At the end of the spawning season, semen was collected without anesthesia by abdominal massage from 37 rainbow trout according to different age groups. In collected semens, color, volume, motility, activity time (duration of motility), concentration, total spermatozoa and pH were recorded. Furthermore, body weight and body length were measured and correlations beetween spermatological properties and these parameters were assessed. In the 1-2 years age group, volume (ml), motility (%), activity time (s), concentration (x 10^9 sp/ml), total spermatozoa (per ejaculate) and pH were 9.7, 81.0, 79.0, 8.97, 87.0 and 7.20 respectively; in the 2-3 years age group, these values were 14.1, 88.5, 81.0, 7.89, 111.2 and 7.40 respectively; in the 3-4 years age group, these values were 30.6, 86.1, 82.6, 4.80, 146.8 and 7.22 respectively; and in the 4-5 years age group these values were 34.8, 88.1, 155.0, 5.50, 191.4 and 7.31 respectively. In these determined properties, differences between group averages were significant. When the correlations between obtained values in all age groups were estimated, it was found that there was a positive relation between body weight and length with semen volume. In contrast, there was a negative correlation between concentration and these values (p > 0.05). In addition, it was observed that there was a positive relation between body weight, length and semen volume with activity time (p < 0.05). Consequently, it was determined that body measurements and spermatological properties changed as age increased in rainbow trout. In particular, increased volumes, motility, activity time and total spermatozoon number and decreased concentration were observed. Furthermore, the highest motility was determined in the 2-3 years age group and a positive correlation (p < 0.05) was observed between body measurements and semen volume and motility in this group.

Keywords: Rainbow trout, semen, spermatological properties, age

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