Sperm production of Russian sturgeon (A. gueldenstaedtii) raised on an industrial cage farm

Stanimir Bonev, Boyko Georgiev, Lyudmila Nikolova, and Paulina Taushanova

Abstract: Sturgeons are in unusual conditions when farmed on industrial farms, which can affect their development. In this connection, the qualitative and quantitative characteristics of the semen of fish reared under similar conditions are of interest. The study covers 7, 8 and 9 year old Russian sturgeon raised on a super-intensive cage farm located in a large dam in southern Bulgaria. Sperm concentration, total motility, motility and movement characteristics were determined by using a CASA system. The levels of some enzymes were determined by spectrophotometric measurement. The average volume in the individual age groups ejaculate is from 10.50 ml (8-year-old), to 153 ml (7-year-old fish). The indicator has a very high variation, reaching 8.96% in 8-year-old fish. In this age group the variation in the concentration of sperm is the highest - from 56.89 to 2917.15 x 106 / ml. The highest sperm motility was found in 9-year-old fish (98.54%). VCL ranges from 14.40 to 160.03 μm / s; VSL from 0.50 to 116.24 μm / s; VAP from 1.80 to 140.17 μm / s; LIN from 3.40 to 73.90%; STR from 28.0 to 93.90%; WOB from 12.20 to 87.59%; ALH from 0 to 5.14 μm; BCF from 0 to 7.56 Hz. The spermatozoa had the worst indicators in 8-year-old fish characterizing the movement, as the percentage of static ones reached 46.04%, which significantly exceeds (p < 0.05) the same in 7- and 9-year-olds by 15.35 and 31.53 times, respectively. In most of the studied enzymes, the semen of 8-year-old Russian sturgeon has significantly lower levels of AP, CK, LDH in water extract compared to 7 and 8-years old group. The differences of this group with 7- and 9-year-olds are significant (p < 0.05) respectively 2.36 and 2.44 times; 16.03 and 17.05 times; 2.68 and 2.59 times. Only on GGT in water extract in 8-year- old individuals the level of the enzyme is the highest, but the differences between the groups are not significant.

Keywords: CASA; enzymes; motility; spermatozoa; Sturgeon

Date published: 2022-11-02