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
The aim of this study will determine the relative contributions of food sources in yellow tail lambari (Astyanax lacustris) monoculture and in integrated system with Amazon River prawn (Macrobrachium amazonicum) and curimbata (Prochilodus lineatus) using stable isotope composition (´13C and ´15N). A completely randomized experimental design will be carried out in 12 experimental earthen ponds (0.1 ha) with three treatments and four replicates each. The treatments will consist in T1 - monoculture of A. lacustris (ML); T2 - integrated system of A. lacustris and M. amazonicum (LP); T3 - integrated system of A. lacustris, M. amazonicum and P. lineatus (LPC). Only A. lacustris will be fed with a commercial diet with 36% crude protein two times a day. M. amazonicum and P. lineatus will be fed only use the organic material produced by target fish (A. lacustris), such as waste feed and fish faeces. Samples of consumers and food sources such plankton, organic matter in sediment, benthic macrofauna, fish faeces, and inert diet will be collect monthly during the culture to be processed and subjected to the stable isotopes analysis of ´ 13C and ´ 15N. The results will be applied to the Bayesian Mixing Model by the Mix SIAR software (Stable Isotopes Analysis in R). The ´15N composition and the trophic position of consumers will be calculate in all farming systems. Another experiment will be conducted to determine the fractionation factor between the three species and the inert diet used in the main study. From these data, the main food sources contribution for the three species and the trophic levels in each type of culture system will be determined.
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