The presence of female and male offspring clearly indicates that the Siberian sturgeon female that produced the offspring was not a “superfemale”. A “superfemale”, therefore, is a female of the WW genotype that will produce only females when mated to a male with a ZZ genotype. The aim of the study was to determine whether the gynogenetic Siberian sturgeon female that produced the offspring that were evaluated was a “superfemale” (WW) or a normal female (ZW). Molecular analysis based on five microsatellite DNA loci was conducted for all the fish for which there were evaluations. The average gonadosomatic index was determined to be 2.72% and 2.80% in the first and second groups, respectively. The first examined group consisted of 20% females, 45% males and 35% sexually undifferentiated individuals, whereas the second group was composed of 30% females and 70% males. Gonadal fragments were examined histologically to identify the sex ratio and the sexual maturation stage. Gonads were sampled twice from 30 randomly selected individuals. This is the first report of reproduction of a gynogenetic female Siberian sturgeon (Acipenser baerii) and subsequent production of viable offspring with differentiated gonads. The present findings will lay the foundation for future research on this pathogen in Siberian-sturgeon aquaculture. Drug sensitivity testing showed that the isolate is sensitive to quinolones, aminoglycosides, nitrofurans, amphenicols, and tetracyclines. Virulence gene profiling revealed the presence of seven virulence genes related to pathogenicity (acyltransferase, phospholipase A, serine protease, heat-stable cytotonic enterotoxin, nuclease, and aerolysins A and B) in this A. ruthenus were determined: 8.37 × 10⁵ and 2.89 × 10⁶ colony-forming units per milliliter, respectively. Half-lethal doses (LD50) of isolate AB005 for O. A pathogenicity test was carried out for the isolate on healthy Oreochromis niloticus and Acipenser ruthenus via intraperitoneal injection along the caudal peduncle of the fish. hydrophila in an analysis of its morphological, physiological, and biochemical features and 16S ribosomal-RNA and gyrB gene sequences.

This isolate, tentatively named AB005, was identified as A. In the present work, our purpose was to isolate and characterize dominant bacteria in diseased A.

hydrophila infection in Kazakhstan are still inconclusive. Aeromonas hydrophila is the most important sturgeon pathogen in Kazakhstan, but studies on A. This species faces an increased risk of Aeromonas infections. To date, attempts have been made to increase the number of sturgeons through artificial reproduction in aquaculture and a release of the resultant juveniles into the Ural River, which flows into the Caspian Sea. The Siberian sturgeon (Acipenser baerii) is a long-lived and late-maturing fish its natural populations are considered endangered and listed in the first class of protected animals in Kazakhstan.

Mindray dp 6600 vet manual pdf