RESUMO
Cystatin proteins are known to form a superfamily of cysteine protease inhibitors, which play a key role in protein degradation and are related to different physiological processes, such as development and immunity. Currently, numerous immunoregulatory proteins, such as cystatins, are being used in the control and prevention of diseases in aquaculture. Thus, the objective of this study was to produce recombinant cystatin (rCYST-B) from the red piranha Pygocentrus nattereri and to evaluate its effect on bacterial growth. The gene that encodes cystatin-B was isolated from the spleen of P. nattereri and cloned in an expression system. The protein was produced via a heterologous system involving the yeast Pichia pastoris X-33. The inhibitory activity of purified cystatin-B was evaluated on papain using different concentrations (0-80.0 µg/µL) of rCYST-B. The bacteriostatic action of the protein was evaluated using the Kirby-Bauer method on the growth of Escherichia coli and Bacillus subtilis. rCYST-B showed 100% inhibition at a concentration of 60 µg/µL. Moreover, the bacteriostatic activity of E. coli and B. subtilis showed inhibition of 40.36 and 49.08% compared to the negative control (phosphate buffer), respectively. These results suggest that recombinant CYST-B has biotechnological potential for use in aquaculture.
RESUMO
RESUMEN La región de la Orinoquia, se caracteriza por poseer espejos de agua que se mantienen durante todo el año, aportando peces para consumo local. La pesca artesanal constituye la principal actividad económica de sustento de comunidades ribereñas, quienes están siendo amenazadas en su seguridad alimentaria, por la disminución del recurso íctico, debido a múltiples causas atribuidas a la actividad humana. Por lo anterior, sistemas de producción en jaulas flotantes, elaboradas con materiales de bajo costo y ubicadas en cursos de aguas naturales, constituyen una alternativa económica para estas comunidades. El objetivo fue evaluar el rendimiento productivo de la cachama blanca en jaulas flotantes, ubicadas en el río Manacacias, manejando tres densidades: 150, 200 y 250 peces/m3. Se sembraron alevinos en jaulas, con dimensiones de 10,2 m³ (3 x 2 x 1,7 m). Los peces fueron alimentados con alimento balanceado, durante 126 días. Al final del experimento, los individuos fueron cosechados. Se produjo una biomasa promedio por densidad de 47,42 kg/m3, en la densidad 150; 45,11 kg/m3, en 200 peces/m3 y 79,65 kg/m3, en la densidad 250. Su conversión alimenticia fue 1,1; 1,32 y 0,8, la sobrevivencia de 83,51, 78,98 y 93,72 %, respectivamente. Se concluye, que la cachama blanca puede ser cultivada en jaulas flotantes a altas densidades, obteniendo parámetros productivos óptimos y, adicionalmente, puede ser una fuente de ingresos significativa para las comunidades.
ABSTRACT The Orinoquia region is characterized by having water bodies that are maintained throughout the year, providing fish for local consumption. Artisanal fishing constitutes the main economic activity for the livelihood of riverine communities, which are being threatened in their food security by the decrease in the fish resource due to multiple causes attributed to human activity. Therefore, production systems in floating cages, made with low-cost materials and located in natural water courses, constitute an economic alternative for these communities. The objective of this work was to evaluate the productive performance of white cachama in floating cages located in the Manacacias river, managing three densities 150, 200 and 250 fish/m3. Fingerlings were sown in cages with dimensions of 10.2 m³ (3 x 2 x 1.7 m). The fish were fed with balanced feed for 126 days. At the end of the experiment the individuals were harvested in three cages for the three densities. An average biomass by density of 47.22 kg/m3 was produced at density 45.11 kg/m3 in 200 fish/m3 and 79.65 kg/m3 at density 250. Its feed conversion was 1.1, 1.32 and 0.8, the survival of 83.51, 78.98 and 93.72 % respectively. It is concluded that cachama blanca can be cultivated in floating cages at high densities, obtaining optimal productive parameters and additionally, it can be a significant source of income for the communities.
