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Histomorphological and Dynamical Changes in Female River Lampreys during Maturation under Controlled Conditions as a Part of Lamprey Restoration Programs
by
, , , , and
Joanna Nowosad
1,2,*,
Roman Kujawa
3,
Shahid Sherzada
4,
Dariusz Kucharczyk
1,3,*,
Mateusz Mikiewicz
5,
Katarzyna Dryl
6,
Andrzej Kapusta
2,
Joanna Łuczyńska
7 and
Hany M. R. Abdel-Latif
8
1
Department of Research and Development, Chemprof, 11-041 Olsztyn, Poland
2
Department of Ichthyology, Hydrobiology and Aquatic Ecology, National Inland Fisheries Research Institute,10-718 Olsztyn, Poland
3
Department of Ichthyology and Aquaculture, University of Warmia and Mazury in Olsztyn, 10-720 Olsztyn, Poland
4
Department of Zoology, Government College University, Lahore 54000, Pakistan
5
Department of Pathological Anatomy, Faculty of Veterinary Medicine, University of Warmia and Mazury in Olsztyn, 10-719 Olsztyn, Poland
6
Department of Gamete and Embryo Biology, Institute of Animal Reproduction and Food Research, Polish Academy of Sciences, 10-243 Olsztyn, Poland
7
Department of Commodity and Food Analysis, University of Warmia and Mazury in Olsztyn, ul. Plac Cieszyński 1, 10-726 Olsztyn, Poland
8
Department of Poultry and Fish Diseases, Faculty of Veterinary Medicine, Alexandria University, Alexandria 22758, Egypt
*
Authors to whom correspondence should be addressed.
Animals 2024, 14(17), 2516; https://doi.org/10.3390/ani14172516
Submission received: 28 July 2024
/
Revised: 25 August 2024
/
Accepted: 26 August 2024
/
Published: 29 August 2024
(This article belongs to the Special Issue Reproduction and Development in Fish: Solving Bottlenecks in Modern Aquaculture)
Simple Summary
Lampreys are a group of about 40 species found all over the world. One representative of this group is the river lamprey, which spends its larvae life initially in fresh water and then in the sea. For spawning, which is the end of their last migration, they return to fresh water. The spawning migration period lasts many months, during which the lampreys do not eat and many changes occur in their bodies. However, knowledge of these processes and their dynamics has not been studied and described, and this is the basis for preparing programs for the restitution of lampreys and their artificial reproduction under controlled conditions. This paper describes the changes occurring during spawning migration in female river lampreys, including the development of ovaries, changes in the liver, and atrophy of the digestive system.
Abstract
More than 40 species of lampreys (Petromyzontiformes) are known worldwide. Some of them are parasitic and feed on the blood of fish or other aquatic animals. Lampreys spawn once in their lifetime, after which they die. One of the representatives of the ichthyofauna of European rivers is the river lamprey, Lampetra fluviatilis. The river lamprey is now an endangered species due to loss and degradation of their habitats. The present study investigated gonadal development without hormonal stimulation in female river lampreys during puberty under controlled conditions for a period of seven months. Female river lampreys were kept in conditions that mimicked the natural environment. During the November–May period, samples were taken monthly to determine the extent of gonadal development and gastrointestinal and liver changes using histological examination. From the results obtained, the dynamical changes were determined for the following: gonadosomatic index (GSI; %), hepatosomatic index (his; %), and digestivesomatic index (DSI; %). With the gonadal development of female lampreys, an increase in GSI (7–23%; November–May) and a decrease in DSI (0.4–0.1%; November–May) histological changes were observed in the gonads (oocyte development), intestines (over time, decreased lipid vacuoles and enterocyte apoptosis), and in the liver (decreased lipid vacuoles and hepatocyte apoptosis over time) and in the digestive system resulting from its degradation. Also, it was observed that there was a change in the color of the liver to green in April. This study demonstrated the key role of the liver in the oocyte maturation process in this species.
