Influence of different sizes of gneiss rock substrates on the larval rearing of tilapia Oreochromis niloticus

• Grant number: 22/01591-1
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: June 01, 2022
• End date: December 31, 2024
• Field of knowledge: Agronomical Sciences - Animal Husbandry - Animal Production
• Principal Investigator: Vander Bruno dos Santos
• Grantee: Antonio Carlos Kida Filho
• Host Institution: Instituto de Pesca. Agência Paulista de Tecnologia dos Agronegócios (APTA). Secretaria de Agricultura e Abastecimento (São Paulo - Estado). São Paulo , SP, Brazil

Abstract

The objective of this study is to evaluate the influence of the gneiss rock substrate of different sizes on the main parameters in water and its effects on the growth of tilapia larvae. The experiment will be conducted at Instituto de Pesca/APTA/SAA for 2 months. Tests will be carried out with tilapia post-larvae, with 5 treatments being evaluated, considering twenty 15-liter aquariums with different types of substrates. The evaluated substrates will come from gneiss rock of different granulometric (coarse gravel sand, fine gravel sand, fine gravel, gravel dust), for the control treatment the substrate with quartz gravel will be used. All aquariums will have a circulation pump and external filtration (Hang-on type filters), temperature between 25 and 28°C, and natural photoperiod. The parameters of oxygen, pH, ammonia, and nitrite will be evaluated weekly. Tilapia post-larvae will be used at a density of 1 post-larvae/liter. The post-larvae will be fed 4 times a day, with specific feed according to the growth phase. The fingerlings will be evaluated every 15 days for survival and weight gain, is individually weighed, and measured after eugenol stunning. The experimental design will be completely randomized, being evaluated 5 substrates with 4 replications (aquaria). The growth study will be done by fitting all fingerling weight data to the exponential model yi = Aekxi + ei, where "y" is the observed weight of each fish, i = 1, 2,. .., N; A, the estimated initial weight; and, the base over the natural logarithm; K, the specific growth rate; xi, the age of the fish, and ei, the error associated with each observation, which by hypothesis is NID (0, ò). The parameters of the curves will be compared by their confidence intervals at 95% probability. For statistical analysis, the GLM and MODEL procedures from SAS OnDemand for Academics, Copyright © 2020 SAS Institute, will be used.(AU)