Isotopic composition and relative contribution of food sources in a monoculture of yellow-tail lambari (Astyanax lacustris) and in an integrated culture with Amazon river prawn (Macrobrachium amazonicum) and curimbata (Prochilodus lineatus)

Author(s)

Andre Zuffo Boaratti

• Document type: Doctoral Thesis
• Press: Jaboticabal. 2022-06-03.
• Institution: Universidade Estadual Paulista (Unesp). Faculdade de Ciências Agrárias e Veterinárias. Jaboticabal
• Defense date: 2022-02-24
• Advisor: Patricia Maria Contente Moraes Valenti

Abstract

The main objective of this work was to determine the isotopic composition of δ13C and δ15N and the qualitative and quantitative contribution of the main food sources of the yellow-tail lambari (Astyanax lacustris), Amazon river prawn (Macrobrachium amazonicum) and curimbata (Prochilodus lineatus), reared in monoculture system of A. lacustris (LM), integrated system of A. lacustris with M. amazonicum (LP) and integrated system with the three species A, lacustris, M. amazonicum and P. lineatus (LPC), reared in earthen ponds. First of all, an trial was carried out to obtain the isotopic discrimination factors (Δ) between consumers and the standard food source (commercial feed). These values are important to correct the isotopic signal of food sources for applying mixing models. Individual trials were carried out for the three species, in which a commercial feed of 36% protein content was used. It was the same commercial feed used in the grow-out phase of the experiment. Next, tissues from the animal’s musculature were collected for stable isotope analysis. After stabilizing the isotopic signal of the musculature in relation to the commercial feed, the Δ was calculated. The results for A. lacustris were ∆13C of 2.0 ‰ and ∆15N of 2.9 ‰; for M. amazonicum ∆ 13C of 2.3 ‰ and ∆15N of 3.0 ‰; and for P. lineatus ∆ 13C of 1.8 ‰ and ∆ 15N of 3.1 ‰. After obtaining the isotopic discrimination factors, a grow-out experiment was carried out to determine which food sources were actually incorporated into the biomass of the three species. This experiment had three treatments with four replicates. The treatments were Lambari Monoculture (LM), Lambari and Prawn (LP) and Lambari, Prawn and Curimbatá (LPC), all in earth ponds. The management of the culture was done according to commercial production and using a commercial feed. Isotopic signals were obtained from the muscle tissue of the three consumers and all possible food sources available in the culture systems. Then, the analysis of stable isotopes was applied through Bayesian mixture models, with validation by diagnostic test to determine the food sources that were incorporated into the muscles of consumers. The commercial feed was the primary food source for A. lacustris (51 to 75%), while the other food sources had reduced individual participation, but the autochthonous sources added together reached from 25 to 49% of the incorporated food. M. amazonicum presented low incorporation of commercial feed, and the other foods presented heterogeneous contributions without any food source standing out. The results suggested that P. lineatus may present selectivity of absorption and incorporation of sediment resources. Commercial feed was the main source of food incorporated when available for consumption, but in its absence, P. lineatus can develop with autochthonous resources. (AU)

• FAPESP's process: 18/15702-4 - Main food sources in monoculture of yellow tail lambari (Astyanax lacustris) and in integrated system with Amazon River prawn (Macrobrachium amazonicum) and curimbata (Prochilodus lineatus), using stable isotopes
• Grantee: Andre Zuffo Boaratti
• Support Opportunities: Scholarships in Brazil - Doctorate