Spawning Performance and Sex Steroid Levels in Female Pikeperch Sander lucioperca Treated with Poly(lactic-co-glycolic acid) Microparticles

Pikeperch Sander lucioperca is a piscivorous species considered a promising candidate for the diversification of intensive aquaculture. This study aimed to determine the effect of a sustained-release delivery system incorporating mammalian gonadotropin-releasing hormone agonist (mGnRHa) into poly(lactic-co-glycolic acid) (PLGA) microparticles on the sex steroid levels and aspects of artificial reproduction of pikeperch. Fish were divided into four groups and injected with 20 µg mGnRHa/kg, 5-day release microparticles encapsulated with 5 µg GnRHa/kg BW (PLGA 5), 20 µg GnRHa/kg (PLGA 20), or 1 mL/kg 0.9% NaCl (control). Cumulative percentage ovulation was 100% in the PLGA 5 group, significantly higher than in other tested groups. No differences among groups were observed in latency or fecundity. The level of 11-ketotestosterone (11-KT) peaked at 40 h post-injection, and was sustained during ovulation, in all treated groups. The 17β-estradiol (E2) concentration increased in the mGnRHa-only group immediately after hormone injection, while both PLGA groups showed a reduction in E2 after injection, continuing to decrease until ovulation. A low dose of mGnRHa in PLGA microparticles significantly improves induction of ovulation and results in acceptable reproductive performance, which may positively affect pikeperch production under controlled conditions.

Canine and Feline Testicular Preservation

The increased interest in breeding dogs and cats and their use as models for other canids and felids demand research to improve reproductive techniques. Among them, testicular cryopreservation stands out. Testicular cryopreservation enables the maintenance of reproductive capacity and allows the establishment of germplasm banks for several species of commercial value or at risk of extinction. Furthermore, it enables the transport of genetic material among different regions. It is noteworthy that this biotechnology represents the only possibility of preserving the fertility of prepubertal animals that have died, so it has great importance in the propagation of the genetic material of animals. The spermatogonia present in the testes can be cultivated in vitro and the sperm obtained can be used in artificial reproduction programs. Although advances have been achieved with the use of testicular fragments to obtain viable and functional germ cells, the establishment of protocols that can be used in clinical routine have not been concluded yet. The testicular cryopreservation process can be carried out through techniques such as slow freezing, fast freezing and vitrification. However, the protocols used for the canine and feline species are still in the experimental phase. Given the importance of the topic, the aim of this review is to draw a profile of the subject approaching the main works on testicular cryopreservation in dogs and cats.

Interconnected three-dimensional anodized aluminum oxide (3D-AAO) metamaterials using different waveforms and metal layers for RGB display technology applications

Research into the artificial reproduction of vibrant colours in natural creatures and the reproduction of their structural colours has generated considerable interest. One inorganic material that have been studied for...

Recommendations on the state of the sturgeon population of the irtysh river and its optimal extraction from the natural environment for reproduction

The results of studying the current state of the Siberian sturgeon population, clarifying the range of its distribution, the number and size-age groups in various sections of the Irtysh River are presented. Preliminary recommendations are given on the possibility of obtaining a small part of the population for the purpose of artificial reproduction. Ecological monitoring was carried out by the route-expedition method, by examining the Yertis River and the estuary areas of large flowing tributaries and reservoirs for the presence and distribution area of rare fish species. The work uses materials of research reports on the program 037 "State accounting and cadastre of fish resources" for 2004-14, data from the archives of Kazniirh LLP.When conducting research, we were guided by the provisions of Normative and methodological documentation. The research is funded by the Ministry of Ecology, Geology and Natural Resources of the Republic of Kazakhstan (Grant no. BR10264205)

Fir Reproduction Technology for Harvesting Coniferous Boughs

The article considers the use of innovative technologies in logging industry. Manufacture of products “for health” can turn into a substantial profit if one approaches the business competently and chooses a low-competitive niche. Nowadays, there are still types of industries where competition is minimal, despite high consumer demand. These include the industrial production of fir needle oil, which is popular with consumers. It is famous for its healing properties and is used in treating colds, intestinal issues, joints, and nervous disorders; in the manufacture of cosmetics and medicines (ointments and creams). However, there are a number of issues related to the organization of the fir needle oil production, which are the basis of legislation in this area. This applies to the harvesting of raw materials. The share of fir stands in the composition of forests is constantly decreasing. In the European part of Russia, it became necessary to find a way to ensure a regular supply of fir needle oil enterprises with the necessary raw materials. The article proposes a new technology for the artificial reproduction of fir plantations for the purpose of their further use in the production of fir needle oil. A periodic cycle, which allows producing fir needle oil wherever a fir plantation is laid out, is recommended. The design of the device has also been developed. It helps to reduce the planting time, the loads on people when forming the planting spot and thereby increase labor productivity. The article materials can serve as a guide for the efficient use of production resources (people and machinery) for those who lease land for fir growing for oil production. For citation: Tsarev E.М., Rukomojnikov K.P., Anisimov S.E., Tatarinov D.S. Fir Reproduction Technology for Harvesting Coniferous Boughs. Lesnoy Zhurnal [Russian Forestry Journal], 2021, no. 6, pp. 79–88. DOI: 10.37482/0536-1036-2021-6-79-88

Domestication Strategies of Tinfoil Barb Barbonymus schwanenfeldii (Bleeker, 1854): Potential Candidate for Freshwater Aquaculture Development

This paper discussed domestication strategies of Tinfoil barb from different populations for evaluation of potential fish candidate for freshwater aquaculture development. Collection and maintenance of wild-caught adult fish was the first step in domestication strategies followed by characterization of fish, broodstocks selection and maturation, control of fish reproduction, and larval rearing. The Tinfoil barb presented an excellent performance to adapt to the new environment. This was indicated by survival rate of the fish acclimated in the captive environment of about 69.28 ± 19.64% for five weeks. Phenotypic characterization revealed that Tinfoil barb collected from Borneo, Java, and Sumatra have different morphological characters. Based on genetic characters, polymorphism percentage and heterozygosity of the Borneo tinfoil barb population provided the highest performance followed by Java and Sumatra. The growth model of all Tinfoil barb populations was allometric negative indicating a faster increase in length than in weight. Reproductive performance presented that the fecundity of Tinfoil barb female from Borneo was the highest (2795-5099 eggs/gram) followed by Sumatra (1822-2976 eggs/gram) and Java (2210 eggs/gram). The artificial reproduction performance of broodstock from Borneo also presented more excellent performance than other population after hormonal treatment. Fertility rate and hatching rate were 94,33+0,29 % and 77,44+1,03%, respectively. Java Tinfoil barb had fertility rate 93+0,05% and hatching rate 73,67+3,15%, while it was no fertility rate and hatching rate obtained from Sumatra brood-stock group. Wild-caught adult Tinfoil barb from Borneo population presented the best performance used for potential brood-stock regarding genetic characters, reproductive performances, and response to artificial reproduction. Future studies need to be concerned with the acceleration of gonad maturation and the improvement of larval rearing technology for improvement of domestication strategies of Tinfoil barb as a potential candidate for freshwater aquaculture development.

In vivo male african catfish sperm obtaining and evaluation for artificial reproduction

African catfish is a valuable unpretentious object of breeding. It is successfully grown in re-circulating aquaculture systems in mild climate areas. However, artificial reproduction of the African catfish has problems with the collecting of high-quality sperm for fertilization of eggs. Abdominal massage does not give results even after appropriate hormonal stimulation: sperm is released in a small volume, often with an admixture of urine and blood. At the same time, most spermatozoa are motionless. This is due to the morphological features of the gonad structure: the seminal tubules are of the percoid type, in which there are seminal vesicles that prevent sperm release. When breeding catfish, the method of slaughtering males is mainly used, followed by the extraction of gonads, their grinding and straining through gauze or a sieve. Therefore, an urgent task is to develop methods for in vivo male African catfish high-quality sperm collecting. This report shows the technique of gonadectomy and surgery techniques for extracting one or both gonads. General anesthesia was performed by immersing the fish in a solution of clove oil. The optimal dose of clove oil for anesthesia was determined as 0.10–0.20 ml/l. The surgical area was treated with an antiseptic solution. The skin was dissected and separated from abdominal muscles. After acutorsion of testicular vessels, the gonad was excised entirely, since with partial resection, the remaining part of the parenchyma oozes, causing inflammation of the abdominal cavity and impaired healing of the surgical wound. Intermittent octal sutures were applied separately to the peritoneum with abdominal muscles and skin to create additional anastomoses and prevent complications.

Сurrent state of artificial reproduction of chum salmon in Primorye Region

Results of 4 salmon hatcheries operation in Primorye Region are overviewed. Dynamics of chum salmon producers return to the rivers is presented for 4 last years. Recent tendency of shifting the peak of return from middle October to late September — early October is noted both for the rivers flowing into Peter the Great Bay (Barabashevka) and for the rivers of central Primorye (Verbnaya and Milogradovka). High percentage of producers aged 2+ was observed in the hatchery rivers in some years (32.9 % in the Barabashevka in 2019, 31.0 % in the Verbnaya in 2020, 37.8 % in the Bezymyanny in 2020). Interannual fluctuations in the number of producers return are possibly caused by malfunctions of hatcheries. A problem of water supply to the hatcheries is considered. Expediency of temperature control at hatcheries is shown. Data on release of chum salmon juveniles in the last decade are presented for each hatchery: the number of juveniles released, the average weight of juveniles, and the timing of release. Total release to the Barabashevka River was 119.29 . 106 juveniles, to the Ryazanovka — 114.24 . 106 juveniles, to the Poyma — 49.43 . 106 juveniles, to the Narva — 6.02 . 106 juveniles, to the Brusya — 3.11 . 106 juveniles, to the Verbnaya — 69.66 . 106 juveniles, to the Milogradovka — 1.00 . 106 juveniles, to the Lidovka — 1.71 . 106 juveniles, to the Bezymyanny — 69.45 . 106 juveniles, and 2.00 . 106 juveniles each to the Kievka and Margaritovka Rivers.