WWW.WAS.ORG • WORLD AQUACULTURE • JUNE 2024 59 Study Description We collected juvenile prawns from the Jamapa River, Municipality of Boca del Río, Veracruz, México and transported them to the Laboratorio de Producción Acuícola of UNAM FES Iztacala. After three weeks of acclimation to laboratory conditions we started the feeding trial (Figure 2). A basal diet was formulated with casein (39.55 g of inclusion per 100 g of diet), soybean oil (12 g), and potato starch (10 g) as main ingredients. Mineral and vitamin mixtures (5 and 1.9 g, respectively), glucosamine-HCl (0.8 g), sodium citrate (0.3 g), sodium succinate (0.3 g), k-carragenan (2.5 g) and a-cellulose (inclusion depending on cholesterol quantities) were also used in the formulation. The basal formulation was supplemented with 0 (Chol-0), 0.5 (Chlo0.5), 1 (Chlo-1.0) or 1.5 (Chlo-1.5) g of cholesterol/100 g and four experimental diets were produced. The mean proximate composition of the diets was: crude protein, 39 percent; crude lipid, 12 percent; ash 5 percent, and moisture, 3 percent. We used a recirculation system with 12 fiberglass tanks of 50-l each for the feeding trial. Five juvenile prawns with a mean initial weight of 0.24 g were randomly stocked in each tank and the respective diet was fed to triplicate groups at 9 percent of the total biomass. Prawns were fed for a period of 60 days, and at the end of the trial juveniles were weighed and samples of muscle (for contents of protein and lipids) and hepatopancreas (for cholesterol contents) were obtained. For the evaluation of protein content in muscle, we used the technique reported by AOAC (1995) and for the lipids, extraction with chloroform and methanol (Blight and Dyer 1959). Regarding the hepatopancreas cholesterol content, samples were extracted The cinnamon freshwater prawn Macrobrachium acanthurus (Figure 1) is native to the Americas, and distributed along the Atlantic coast from the United States (North Carolina) to Brazil (Rio Grande du Sul) (García-Guerrero et al. 2013). In several countries, this species represents an important resource for local communities of fishermen, as it has cultural, gastronomic, and commercial value (Frías-Gómez et al. 2023). The increasing demand for this species has caused uncontrolled artisanal fisheries and over-exploitation of natural populations. So, overfishing, and other factors such as water contamination from municipal and industrial discharges, and dam constructions are affecting the populations, causing its gradual disappearance from its natural range (Loran-Nuñez 2017). The culture of this species has been suggested for several decades (Kutty and Valenti 2010), but only a few advances have been to date. Knowledge of nutrient requirements is basic to develop practical diets that allow the aquaculture supplementation of M. acanthurus. In the Laboratorio de Producción Acuícola of the Facultad de Estudios Superiores Iztacala-Universidad Nacional Autónoma de México (UNAM FES Iztacala), we have been working for several years on nutrient requirements of M. acanthurus with the final objective of using practical and economically feasible diets for its culture. Particularly, cholesterol is an essential nutrient for crustaceans, as they are unable to accomplish its de novo synthesis, and dietary inclusion is related to proper growth, normal molting, and survival (Teshima et al. 1997). The level of inclusion depends on the species, and stage of development. (Kumar et al. 2018). Considering the importance of dietary cholesterol for crustaceans, the present study describes the cholesterol requirement for the juvenile stage of the cinnamon freshwater prawn M. acanthurus. Dietary Cholesterol Requirement for the Juvenile Cinnamon River Prawn, Macrobrachium acanthurus Alfredo Maldonado-Shibayama, Mario Alfredo Fernández-Araiza, Susana Alejandra Frías-Gómez, Mauricio Castillo-Dominguez and Luis Héctor Hernández-Hernández FIGURE 1. Male of Macrobrachium acanthurus collected from Rio Jamapa, Veracruz, México. FIGURE 2. Some aspects of this study with juvenile Macrobrachium acanthurus. (CONTINUED ON PAGE 60)
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