هورمون درمانی در ماهی: کنترل چرخه تولید مثل

Hormonal Therapy in Fish: Control of the Reproductive Cycle

The use of hormonal therapy in fish is a crucial aspect of fish farming, particularly in species where one sex has faster growth rates than the other. Hormonal therapy is employed to manage the reproductive cycle and optimize growth, weight, and size in fish for economic gain. The two primary reproductive stages, gametogenesis (oogenesis and spermatogenesis) and maturation (oocyte maturation and spermiation), are controlled by different reproductive hormones produced in the pituitary and gonad, i.e., gonadotropin hormones (Gths) and steroids.

Gonadotropin Hormones (Gths)

Gonadotropin hormones, such as follicle-stimulating hormone (FSH) and luteinizing hormone (LH), are used to control the maturation phase of reproduction in fish. These hormones stimulate the production of sex steroids (estrogens, progesterone, and testosterone) in the gonads (ovary and testis). Hormone therapies based on gonadotropin releasing hormones (GnRHs) and luteinizing hormone receptor agonists (human chorionic gonadotropins or pituitary extracts) are commonly used to control the maturation phase in fish.

Recombinant Gonadotropin Hormones (rGths)

The use of relatively new recombinant gonadotropin hormones (rGths), including recombinant FSH (rFSH) and luteinizing hormones (rLH), can open new strategies in aquaculture to treat reproductive disorders and develop out-of-season breeding programs. In vivo treatments have been developed, focusing on the final maturation and spermiation/ovulation stages by single or double rGths injections. However, fish species arrested at the early stages of the reproductive cycle require control of gametogenesis, which usually requires long-term treatments of repeated injections that maintain elevated plasma levels of specific Gths.

Corticosteroids

Corticosteroids are essential for the reproduction of teleost fish. They act as hormones, regulating reproductive processes, and are involved in stress responses, immune system function, and metabolism. The use of corticosteroids in fish production is not common, but they can be used for spawning induction, especially in species like Pimephales promelas. However, the use of corticosteroids can have harmful effects on humans, animals, and the environment if used indiscriminately.

Estrogen Regulation

Estrogen is a female sex hormone that plays essential roles in the reproductive biology of vertebrates, including fish. It is involved in the physiological and pathological states of both males and females and has been implicated in mandible conservation and circulatory and central nervous systems. Estrogen is used for producing all female stock in fish, especially in carp, but the withdrawal period needs to be closely monitored during production.

Androgen Manipulation

Androgen hormones, such as testosterone, are used in fish farming to increase growth and weight in male fish. However, their use can have harmful effects on humans, animals, and the environment if not managed properly.

Recombinant Hormones

The development of recombinant hormones, such as rFSH and rLH, has provided new opportunities for aquaculture to treat reproductive disorders and develop out-of-season breeding programs. These hormones can be used to induce oogenesis from previtellogenesis to obtain eggs and larvae in intensive conditions. However, further research is needed to improve the results obtained from rFSH and rLH treatments.

In conclusion, hormonal therapy in fish is a vital aspect of fish farming, allowing for controlled reproduction and the development of aquaculture production. While hormonal therapies can increase growth and weight in fish, they also pose risks to human health, animal welfare, and the environment if not managed properly. Further research is needed to improve the effectiveness and safety of hormonal therapies in fish.

هورمون درمانی در ماهی یک方面 اساسی از پرورش ماهی است، به ویژه در گونه هایی که جنس یکی از آنها نرخ رشد سریعتری دارد. این مطلب به بررسی هورمون های مختلف مورد استفاده در کنترل چرخه تولید مثل و بهینه سازی رشد، وزن و اندازه در ماهی می پردازد.