Age-related sperm quality of male Heterobranchus longifilis broodstock fed two different isonitrogenous feeds

Abstract

The semen quality of Heterobranchus longifilis broodstocks aged ½, 1½ and 2½ year-old were examined at 1½-, 2½- and 3½-year-old; after feeding with isonitrogenous commercial and local feeds of 42% crude protein for one-year. Statistical analysis revealed that semen quality of the broodstocks showed no significant (p>0.05) difference based on feed type, though broodstock fed commercial feed recorded slight increases over those fed farm-made feed as: milt volume (3.77; 3.75 ml), sperm motility (68.38; 68.11%), sperm concentration (1.69 x 10³; 1.67 x 10³ spermatozoa ml^-1), spermatocrit (19.42; 19.60) and gonadosomatic index (0.76; 0.75), respectively. However, the semen quality parameters of broodstock increased significantly (p<0.0001) with age of broodstocks except spermatocrit which was in reverse order. The milt volume, sperm motility, sperm concentration, spermatocrit and gonadosomatic index of broodstock were 4.79 ml, 84.24%, 1.86 x 10³ spz ml^-1, 18.37 and 0.90respectively for the oldest broodstock, 3½ years-old; and 2.78ml, 55.23%, 1.5 x 10³ spz ml^-1, 21.55, and 0.63 respectively for the youngest broodstock, 1½ A significant interaction in milt volume, sperm motility, and sperm concentration between feed types was observed irrespective of age. The non-significant (p>0.05) difference in semen quality of H. longifilis broodstocks due to feed type suggests that farm-made feed of 42% crude protein level could be utilized in rearing and maintaining 3½- and 2½-year-old male broodstocks of H. longifilis, at lower and affordable cost, till they attain sexual maturity.

Keywords: Broodstock management, gonad somatic indices, sexual maturity, paternal age