Aquaculture Reports (Aug 2024)
Effects of temperature on ovarian development of mandarin fish (Siniperca chuatsi) and hormone therapy to induce its ovulation out of breeding season
Abstract
The objective of this study is to investigate a viable and effective method for artificially breeding the mandarin fish (Siniperca chuatsi) in the out-of-breeding season. The mature development of the female mandarin fish's gonad was induced through precise control of water temperature. Measurements were taken during the temperature control period, including body weight, body height, ovulation rate, relative fecundity and gonadosomatic index (GSI). Serum hormone levels were assessed, and histological sections of gonadal tissues were tracked. Subsequently, a series of experiments were conducted to establish the optimal protocol for hormone-induced ovulation and artificial fertilization. The findings revealed that manipulation and elevation of the aquaculture water body temperature could effectively induce gonad development and maturation in mandarin fish. In the high temperature group (HT, water temperature maintained at 25 ± 1 ℃), 81.25 % of the experimental fish reached maturity within 20 days. Subsequent hormone injection resulted in successful ovulation, normal fertilization, and subsequent incubation of viable young fish. Furthermore, the outcomes of the ovulation test using hormones demonstrated that the pairing of luteinizing hormone releasing hormone (LHRH-A2) and domperidone (DOM) proved highly effective in inducing ovulation in mature mandarin fish in the out-of-breeding season. The ideal dosage for a single injection of this combined hormone was determined to be 6 μg LHRH-A2 and 4 mg DOM / kg of body weight. Employing this optimal hormone dosage resulted in a fertilization rate of 83.23 %, a ovulation rate of 100 %, a relative fecundity of 93.40 ± 17.59 103 / kg and a hatching rate of 88.85 %. The anticipated outcome of these studies is to enhance the artificial breeding techniques for mandarin fish in commercial aquaculture, allowing for year-round production of fertilized eggs.
