Hormonal induction in Paracheirodon axelrodi, Schultz (1956)

• Grant number: 23/10093-8
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: February 01, 2024
• End date: December 31, 2024
• Field of knowledge: Biological Sciences - Physiology
• Principal Investigator: Sergio Ricardo Batlouni
• Grantee: Felipe Ricardo Santos de Almeida
• Host Institution: Centro de Aquicultura (CAUNESP). Universidade Estadual Paulista (UNESP). Campus de Jaboticabal. Jaboticabal , SP, Brazil

Abstract

The Paracheirodon axelrodi is an endemic species of South America, native to the Rio Negro and the Rio Orinoco, and accounts for approximately 56% of ornamental fish exported by Brazil. The P. axelrodi is currently subject to intensive wild extraction for commercialization purposes. To address this pressing issue, the objective of this study is to enable the reproduction of the P. axelrodi in captivity through hormone induction using newly patented methodology involving hypophysation with lambari pituitary extract (EBHL) (patent BR1020210183306). For that, two experiments will be conducted, both with a completely randomized design. The first experiment will test different single doses of EBHL administered at 22:00h, with the following concentrations: T1 (3 mg/kg of EBHL), T2 (6 mg/kg of EBHL), T3 (9mg/kg of CPE), T4 (12 mg/kg of EBHL) and a control group (0.9% saline). There will be a total of five treatments, each with four replicates (5x4). Each treatment will contain 3 fish per experimental unit (two males and one female), resulting in 60 fish and 20 experimental units (incubators). The second experiment will test EBHL in fractional doses. The treatments, replicates, and experimental units will remain the same as in the first experiment. However, the doses applied to females will be fractionated. They will receive 10% of the total dose at 12:00h and the remaining 90% at 24:00h. Males will receive the total dose at 22:00h. The effectiveness of these treatments will be tested and compared through histological analyses of the ovaries and reproductive performance. The use of pituitary extract from a native species such as the lambari to induce spawning in P. axelrodi holds the potential to optimize the production of both species and offers a sustainable alternative to wild extraction of a important ornamental species.