Seasonal Variation in Semen Characteristics and Biochemical Composition of Seminal Plasma of Mrigal, Cirrhinus mrigala (Ham.)

Abstract

The milt quality parameters such as percentage of spermatozoa motility, duration of motility, sperm concentration, and seminal plasma composition of milt of Cirrhinus Mrigala (C. mrigala) varied throughout the breeding season i.e. from April to September. The motility duration (second) was low in the beginning of season ie. April (42 ± 4.32) and recorded a peak of 97.5 ± 4.12 during July and again started declining and reached to 39 ± 4.76 at the end of the season. The mean pH values of seminal plasma ranged from 8.05 ± 0.19 to 8.6 ± 0.12 with a maximum pH in July. The osmolality of seminal plasma was low during beginning and end of breeding season. The highest osmolality of seminal plasma 291.5 mOsm kg-1 was observed during July. The milt yield ml kg-1 , spermatocrit (%), spermatozoa counts (nos/ml) observed in July were 13.9 ± 3.47, 82.5 ± 4.43, and 33.5 ± 1.4, respectively. The same parameters declined to 3.07 ± 0.76, 69.75 ± 4.78, and 14.3 ± 3.3 at the end of the breeding season. The following are the range of ion concentration during breeding season: Na 88.92 ± 22.22 to 140.5 ± 3.7 m Eq/L, K+ 29.25 ± 5.0 to 52.3 ± 19.28 m Eq/L, and Cl 64.82 ± 3.60 to 174 ± 5.88 m Eq/L. The seasonal declines of Na and Cl ion levels were observed when seminal plasma osmolality values showed lower values. The mean range of total protein, cholesterol, and glucose were 0.105 ± 0.03 to 0.515 ± 0.05 g/dl, 8.52 ± 0.77 to 22.97 ± 2.98 mg/dl, and 0.525±0.05 to 1.83 ± 0.125mg/dl, respectively, during the spawning season. The semen characteristics and biochemical composition of mrigal will help in development of the basic knowledge and the strategies during artificial spawning programmes.