Browsing by Author "Rodriguez, Yamila Eliana"

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    A new approach to fishery waste revalorization to enhance Nile tilapia (Oreochromis niloticus) digestion process.
    (2017-06-01) Rodriguez, Yamila Eliana; Pereira, Nair; Harán, Nora Selma; Mallo, Juan Carlos; Fernández Giménez, Analía Verónica
    The main goal of this research was to analyse in vitro compatibility of Nile tilapia (Oreochromis niloticus) digestive proteinases and enzymes recovered from species comprising fishery waste as Pleoticus muelleri, Artemesia longinaris and Patagonotothen ramsayi. It evaluated the use of exogenous enzymes as feed supplements to increase digestion efficiency in tilapia fingerlings and juveniles (3.5 ± 0.11 g and 11.6 ± 1.5 g, respectively). We successfully have obtained proteinases from fishery waste as source of exogenous enzymes. P. muelleri and A. longinaris enzymes had more activity of acid and alkaline proteinases than P. ramsayi. SDS-PAGE gels demonstrated that Nile tilapia digestive proteinases keep their activity when combined with each exogenous proteinase. Exogenous enzymes varied in their ability to enhance hydrolysis of different feed ingredients. P. muelleri by-products are the best candidates to be employed as feed supplements for tilapia juveniles. Enzymes from this by-product did not affect the activity and integrity of fish digestive enzymes, improved the hydrolysis of different protein sources (fish meal, squid meal, shrimp meal and soybean meal), and maintained its activity after being exposed to high temperatures and acid pHs. Our findings are applicable to other places where O. niloticus is raised utilizing local fishery waste, andalso to different cultured species.
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    Characterization of liquid protein hydrolysates shrimp industry waste: Analysis of antioxidant and microbiological activity, and shelf life of final product.
    (2021-04-19) Pereira, María de los Ángeles; Fangio, María Florencia; Rodriguez, Yamila Eliana; Harán, Nora Selma; Fernández Giménez, Analía Verónica; Bonadero, María Cecilia
    Abstract Proteases from shrimp wastes were characterized and protein hydrolysates were obtained. Shrimp protein hydrolysates (SPH) were produced by autolysis (H0) and added 1% (H1) and 2% vol/vol (H2) enzyme extract of shrimp. The hydrolysis degree was determined using a colorimetric method; the capability of hydrolysates to scavenge free radicals was measured with DPPH, and the antimicrobial activity of the SPH was evaluated by the microdilution test. The degree of protein hydrolysis ranged between 43% (H0) and 71.5% (H2) after 90 min, and it functioned as a source of lysine, leucine, aspartic acid, glutamic acid, and glycine. After 10 min of reaction, all hydrolysates reached 50% of scavenging effect. In addition, the SPH prepared with food additives showed acceptable microbiological quality and pH during 40 days at room temperature. This study aims at introducing a low-cost process which produces SPH with commercial applications in the food industry. Practical applications Currently, shrimp processing wastes represents an environmental and economic problem, since such seafood industry must pay for the landfarming service. This waste treatment is not environmentally efficient, and it affects the value of the final product. However, these wastes have a large number of compounds which hold biological activities of interest that can be used to obtain a high added value product such as protein hydrolysates. This by-product has several potential applications for the food and pharmaceutical industries. In this study, a protein hydrolysate solution was obtained utilizing processed shrimp waste as an enzymatic resource and a protein substrate as well. This research demonstrated the feasibility of obtaining a good protein source that also holds useful antioxidant properties. It is important to highlight that the by-product was obtained without resorting to freeze-drying technology, which makes the industrial process more expensive. To accomplish that, we included low-cost food preservatives and assessed the shelf life of this product of high nutritional quality.
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    Desarrollo de alternativas sustentables para el aprovechamiento de metabolitos disueltos y efluentes semisólidos sedimentables generados durante el cultivo intensivo de tilapia del Nilo Oreochromis niloticus
    (2020-01-01) Zanazzi, Aldo Nahuel; Mallo, Juan Carlos; Rodriguez, Yamila Eliana
    La presente Tesis plantea alternativas para el aprovechamiento de los residuos semisólidos sedimentables (RSS) descartados por el cultivo de peces y los metabolitos disueltos en el agua de los mismos, dentro de las instalaciones del Laboratorio de Acuicultura (LACUI) ubicado en la Universidad Tecnológica Nacional, Facultad Regional Mar del Plata. Primero, se estudiaron algunas características físico-químicas y microbiológicas de los RSS. La mayoría de estos valores estaban dentro de las concentraciones establecidas para vuelcos a la red cloacal, a excepción de los sólidos sedimentables. Además, estos resultados mostraron un adecuado contenido de ciertos nutrientes necesarios para el crecimiento de plantas. Sin embargo, se requieren análisis complementarios para determinar si legalmente pueden ser utilizados con esta finalidad. Por otra parte, se llevó a cabo un experimento con el fin de demostrar el provechamiento de los metabolitos disueltos en agua (resultantes de las excreciones de los peces) para el crecimiento de vegetales. El mismo consistió en desarrollar un sistema biointegrado donde se complementó el cultivo tradicional de tilapia del Nilo en sistemas de recirculación de agua utilizados en LACUI con un sistema hidropónico de cultivo de plantas en agua, testeando el crecimiento de 42 ejemplares de albahaca durante un periodo de 28 días. Las plantas partieron de un peso promedio inicial de 0,5±0,18 g y alcanzaron un peso promedio final de cosecha de 30,4±10,41 g, con una cantidad de hojas (parte comestible) de 4±0,56 al inicio y 19,1±6,88 al concluir el experimento. Los resultados obtenidos se enmarcan dentro del concepto de desarrollo sostenible, poniendo énfasis en el avance de una actividad productiva en crecimiento a nivel mundial como la acuicultura dentro del nuevo paradigma económico de economía circular, el cual plantea entre otras cosas, revalorizar los residuos pudiendo ser aprovechados por otra actividad productiva.
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    Efecto de proteasas exógenas extraídas de desechos del langostino sobre la condición física y fisiológica de los peces de cultivo
    (2019-11-01) Rodriguez, Yamila Eliana; Pereira, María de los Ángeles; Zanazzi, Aldo Nahuel; Asiain, Arturo; Cecchi, Federico Alcides; Waldmann, Paula; Fernández Gimenez, Analía
    Los desechos pesqueros representan una fuente de enzimas para ser utilizadas como aditivos para la acuicultura. Un estudio realizado in vitro demostró que las proteasas de los desechos del langostino Pleoticus muelleri (PM) podrían ser utilizadas como enzimas exógenas para la tilapia Oreochromis niloticus (ON) (Rodriguez et al. 2017). Para comprobar su efectividad es necesario evaluar su eficacia in vivo. El objetivo fue analizar el efecto de PM en la actividad proteolítica endógena y condición física-fisiológica de ON. Ejemplares juveniles de ON (n=63; 23,9±0,42 g) se distribuyeron aleatoriamente en 9 tanques. Durante 6 semanas se expusieron tres tratamientos: Control, microcápsulas con PM inactivo; Langostino: microcápsulas con PM; y Comercial, microcápsulas con aditivo enzimático Ronozyme® ProAct. Las microcápsulas de alginato-bentonita se fabricaron utilizando la técnica de extrusión en Cl2Ca. Se realizaron muestreos semanales para determinar la condición física, la actividad proteolítica intestinal, glucógeno hepático y parámetros del suero sanguíneo. Los peces expuestos al tratamiento de langostino tenían un mayor factor de condición corporal (K=1,8±0,05) con respecto a los del tratamiento control (K=1,5±0,05) y comercial (K=1,5±0,02). La adición de enzimas exógenas influye en la actividad de las proteasas alcalinas intestinales, pero no hay una variación entre las distintas semanas. Las comparaciones múltiples mostraron que su actividad fue significativamente mayor en los peces alimentados con dieta y enzima de langostino (0,7±0,05 U/mL) o comercial (0,6±0,06 U/mL), comparada con la actividad intestinal del control (0,4±0,04 U/mL). No se observaron diferencias significativas en el contenido de glucógeno hepático ni en los parámetros bioquímicos del suero sanguíneo (glucosa, triglicéridos, proteína total). Esta investigación proporciona evidencia sobre los beneficios asociados al consumo del aditivo enzimático elaborado a base de desechos del procesamiento del langostino, debido a que los peces que consumieron este aditivo presentaban una mejor condición física y una actividad proteolítica intestinal equiparable con la de la enzima comercial. Además, no presentaron indicios de trastornos fisiológicos que indiquen un problema de salud.
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    Exogenous proteases from seafood processing waste as functional additives in rainbow trout aquaculture
    (2021-03-01) Rodriguez, Yamila Eliana; Pereira, Nair; Laitano, María V.; Moreno, Pablo; Fernández Giménez, Analía Verónica
    Previous studies about enzyme additives for salmonids employed commercial proteases from bacteria, but research obtaining such enzymes from other organisms are scarce. We aimed to increase digestive protease activity in Oncorhynchus mykiss, by analysing potential sources of exogenous proteases generated from different seafood processing waste. To date, there is no information regarding the influences that exogenous enzymes have on the activity and integrity of endogenous enzymes in salmonids. The compatibility and interaction between endogenous and exogenous proteases were evaluated through protein hydrolysis and electrophoresis. We also evaluated the capacity of two types of microcapsules (Alginate–Chitosan and Alginate–Chitosan– Bentonite) to protect the protease activity after being exposed to the gastric environment of trout. The seafood wastes had activities around 0.23–2.53 U/ml at 15°C. Among all the exogenous proteases evaluated, P. granulosa's extract showed the best performance, followed by L. santolla's extract. Such extracts increased the protein hydrolysis to equal or higher levels than the commercial protease and did not alter the integrity of trout proteases. The optimal catalytic function at low temperatures of these extracts might be linked to the habitat of these arthropods. Alginate–Chitosan– Bentonite microcapsules are recommended in preference to Alginate–Chitosan capsules for delivery of enzymes in salmonids because they ensure the activity of exogenous proteases for longer in acid pH (6 vs. 4 h). This research promotes a re-evaluation of seafood processing wastes through the production of a potentially functional additive that may improve trout protein digestion.
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    Morphological changes, peptidase activity, and effects of exogenous enzymes in the early ontogeny of Nile tilapia, Oreochromis niloticus.
    (2022-07-14) del Valle, Juana Cristina; Zanazzi, Aldo Nahuel; Rodriguez, Yamila Eliana; Haran, Nora Selma; Laitano, María Victoria; Mallo, Juan Carlos; Fernández‐Gimenez, Analía Verónica
    During the early ontogeny, the transition from endogenous (yolk protein) to exogenous feeding (artificial diets) represents a critical period linked to the undifferentiated digestive system, with low digestibility of food protein. The objectives of this work were to characterize the morphology of the early Nile tilapia (Oreochromis niloticus) developmental stages and determine the activity of alkaline and acid peptidase enzymes during the ontogenesis from hatching to 20 days post-hatching (DPH). Also, the in vitro effect that exogenous enzymes from Argentine red shrimp (Pleoticus muelleri) waste have on the alkaline peptidases of larvae from 6 to 20 DPH (which correspond to the age at which fish eat exogenous food) was studied. Both acid and alkaline peptidase activities varied throughout early ontogeny development (from 0.1 to 1, and from 0.1 to 7.1 UE mg protein−1, respectively). The patterns of both enzyme activity variation would be related with changes in endogenous, mixed and exogenous feeding. Our studies show that the additions of the enzyme extract of shrimp have a synergistic effect (from 3 to 6 times) on endogenous in vitro activity. Moreover, the zymogram analysis demonstrates that the bands corresponding to the activity of each species (tilapia and red shrimp) remain active when they are mixed. The increase in peptidase digestive capacity by addition of exogenous enzymes would maximize the assimilation of nutrients from artificial food during early development.