A native strain of Bacillus subtilis increases lipid accumulation and modulates expression of genes related to digestion and amino acid metabolism in Litopenaeus vannamei.

In the field of shrimp aquaculture, the utilization of probiotics represents a promising avenue, due to the well-documented benefits conferred by these microorganisms. In the current study, a Bacillus subtilis strain, referred to as strain E, was isolated from the gastrointestinal tract of the shrimp Litopenaeus vannamei and subsequently identified via molecular methods and phylogeny. The probiotic potential of strain E was characterized, and its application as a feed shrimp additive was evaluated in a 45-day experiment. Several parameters were assessed, including zootechnical performance, muscle tissue proximate composition, hepatopancreas lipid concentration, and the expression of genes associated with digestion, amino acid metabolism, and antioxidant defense mechanisms in various shrimp tissues. Although no significant impact on zootechnical performance was observed, supplementation with strain E led to an increase in lipid concentration within both muscle and hepatopancreas tissues. Furthermore, a marked decrease in the expression of genes linked to digestion and amino acid metabolism was noted. These findings suggest that the addition of the B. subtilis strain E to shrimp feed may enhance nutrient absorption and modulate the expression of genes related to digestion and amino acid metabolism.

Exogenous enzyme complex prevents intestinal soybean meal-induced enteritis in Mugil liza (Valenciennes, 1836) juvenile

ABSTRACT Four soybean meal-based diets containing increasing levels of an enzyme complex (E50, E100, E150 and E200 at 50, 100, 150 and 200 g ton-1, respectively) and one soybean meal-based diet without the enzyme complex (E0) were fed in triplicate to M. liza juveniles in a semi-static flow system with 20 fish per tank for 75 days. There were no differences between the treatments for animal performance parameters, but fish fed the enzyme complex treatment exhibited significantly (P<0.05) higher values of calcium bone retention compared with control fish. Although there was no relationship between bacterial counts in different sections of the gastrointestinal tract or enzyme levels, filamentous bacteria were increased in E50 compared with E150. All of the treatments resulted in higher bacterial counts in the stomach than in intestinal segments. Histological screening showed serious to moderate infiltration of inflammatory cells, modification in villus morphology and necrosis in some cases in fish fed the E0 diet. In addition, fish from the E0 treatment exhibited significantly (P<0.05) lower lipid deposition in the peritoneal cavity. Therefore, the use of low levels of exogenous enzyme is recommended in diets for M. liza when soybean meal is used as the main source of protein.

Exogenous enzyme complex prevents intestinal soybean meal-induced enteritis in Mugil liza (Valenciennes, 1836) juvenile.

Four soybean meal-based diets containing increasing levels of an enzyme complex (E50, E100, E150 and E200 at 50, 100, 150 and 200 g ton-1, respectively) and one soybean meal-based diet without the enzyme complex (E0) were fed in triplicate to M. liza juveniles in a semi-static flow system with 20 fish per tank for 75 days. There were no differences between the treatments for animal performance parameters, but fish fed the enzyme complex treatment exhibited significantly (P<0.05) higher values of calcium bone retention compared with control fish. Although there was no relationship between bacterial counts in different sections of the gastrointestinal tract or enzyme levels, filamentous bacteria were increased in E50 compared with E150. All of the treatments resulted in higher bacterial counts in the stomach than in intestinal segments. Histological screening showed serious to moderate infiltration of inflammatory cells, modification in villus morphology and necrosis in some cases in fish fed the E0 diet. In addition, fish from the E0 treatment exhibited significantly (P<0.05) lower lipid deposition in the peritoneal cavity. Therefore, the use of low levels of exogenous enzyme is recommended in diets for M. liza when soybean meal is used as the main source of protein.

Silencing of Gonad-Inhibiting Hormone Transcripts in Litopenaeus vannamei Females by use of the RNA Interference Technology.

The method usually employed to stimulate gonadal maturation and spawning of captive shrimp involves unilateral eyestalk ablation, which results in the removal of the endocrine complex responsible for gonad-inhibiting hormone (GIH) synthesis and release. In the present study, RNAi technology was used to inhibit transcripts of GIH in Litopenaeus vannamei females. The effect of gene silencing on gonad development was assessed by analyzing the expression of GIH and vitellogenin, respectively, in the eyestalk and ovaries of L. vannamei females, following ablation or injection with dsRNA-GIH, dsRNA-IGSF4D (non-related dsRNA), or saline solution. Histological analyses were performed to determine the stage of gonadal development and to assess the diameter of oocytes throughout the experimental procedure. Only oocytes at pre-vitellogenesis and primary vitellogenesis stages were identified in females injected with dsRNA-GIH, dsRNA-IGSF4D, or saline solution. Oocytes at all developmental stages were observed in eyestalk-ablated females, with predominance of later stages, such as secondary vitellogenesis and mature oocytes. Despite achieving 64, 73, and 71% knockdown of eyestalk GIH mRNA levels by 15, 30, and 37 days post-injection (dpi), respectively, in dsRNA-GIH-injected females, the expected increase in ovary vitellogenin mRNA expression was only observed on the 37th dpi. This is the first report of the use of RNAi technology to develop an alternative method to eyestalk ablation in captive L. vannamei shrimps.

India ink induces apoptosis in the yellow clam Mesodesma mactroides (Deshayes, 1854). Optical and ultrastructural study.

This paper reports on the acute inflammatory and cellular process in the yellow clam, Mesodesma mactroides, induced by injection of India ink into the muscular foot. Histological observations with optical and electronic microscopy were made at 24 and 48 h after injection. The induced cellular inflammatory response consisted of a general hemocyte infiltration without necrosis and apoptotic activity. Migration of ink-laden phagocytes across the intestinal epithelium was recorded. It appeared that the yellow clam "excreted" ink particles through the gill and kidney. The positive staining for apoptosis was observed in the digestive gland. Electronic microscopy revealed ultrastructural changes of endoplasmic reticulum stress and apoptotic bodies in the digestive gland. The mechanism by which the India ink particles induce apoptosis remains unknown, but might possibly be associated with the endoplasmic reticulum stress. This work has highlighted features that require further discussion in the restricted field the inflammatory responses of mollusks.

Ontogenic development of kidney, thymus and spleen and phenotypic expression of CD3 and CD4 receptors on the lymphocytes of cobia (Rachycentroncanadum).

In the present study was evaluated the ontogenic of immunocompetent organs of cobia up to 53 days after hatching (dah) through histology and immunohistochemistry techniques. The kidney was the first lymphohematopoietic organ to appear, at 1 dah, followed by the spleen at 5 dah and the thymus at 7 dah. The first CD3 receptors on the lymphocytes were observed in 27% of the thymic tissue at 7 dah and in 99% at 53 dah. The phenotypic expression of CD3 receptors was registered in 10% of the kidney at 8 dah and in 32% at 53 dah. CD4 receptors were observed in 5% and 63% of the thymic area at 7 and 53 dah, respectively. In the kidney, T4 lymphocytes were first observed at 13 dah in 9% of the organ and in 28% at 53 dah, defining the functional development of the specific system associated with immunological memory capacity.

Thyroid gland development in Rachycentron canadum during early life stages.

The aim of this study was to describe the ontogeny of thyroid follicles in cobia Rachycentron canadum. Larvae were sampled daily (n=15 - 20) from hatching until 15 dah (days after hatching). Following, larvae were sampled every two days by 28 dah; a new sample was taken at 53 dah. The samples were dehydrated, embedded in Paraplast, and sections of 3 µm were dewaxed, rehydrated and stained with HE and PAS. A single follicle was already present 1 dah and three follicles were found 8 dah. The number of follicles increased up to 19 on 53 dah. The diameter of follicles and follicular cell height were lower 1 dah (6.83 ± 1.00 and 4.6 ± 0.01 µm), but increased from 8 dah (24.03 ± 0.46 µm e 6.43 ± 0.46 µm). From 8 dah, the presence of reabsorption vesicles was observed in the colloid and from the 19 dah some follicles did not present colloid. The early thyroid follicle appearance in cobia larvae as well as the high quantity of follicles without colloid and/or with vesicles even after the metamorphosis, might be the explanation of the fast growth of the cobia.

Impairment of the immune system in GH-overexpressing transgenic zebrafish (Danio rerio).

Growth hormone (GH) is an important regulator of immune functions in vertebrates, and it has been intensively reported a series of stimulatory actions of this hormone over on the immune system. Within aquaculture, overexpression of GH has been considered a promising alternative for promoting higher growth rates in organisms of commercial interest. Considering the various pleiotropic effects of GH, there are still few studies that aim to understand the consequences of the excess of GH on the physiological systems. In this context, our goal was to present the effects of the overexpression of GH on immune parameters using a model of zebrafish (Danio rerio) that overexpress this hormone. The results showed that GH transgenic zebrafish had 100% of mortality when immunosuppressed with dexamethasone, revealing a prior weakening of the immune system in this lineage. Morphometric analysis of thymus and head kidney revealed a reduction in the area of these structures in transgenic zebrafish. Moreover, the phenotypic expression of CD3 and CD4 thymocytes was also depreciated in transgenic zebrafish. Furthermore, a decrease was noted in the expression of genes RAG-1 (60%), IKAROS (50%), IL-1ß (55%), CD4 (60%) and CD247 (40%), indicating that development parameters, of innate and acquired immunity, are being harmed. Based on these results, it can be concluded that the excess of GH impairs the immune functions in GH transgenic zebrafish, indicating that the maintenance of normal levels of this hormone is essential for the functioning of immunological activities.

Micobacteriose por Mycobacterium marinum em "linguado" Paralichthys orbignyanus e em "barber goby" Elacatinus figaro: diagnóstico histopatológico e imuno-histoquímico / Micobacteriosis by Mycobacterium marinum in Brazilian flounder Paralichthys orbignyanus and barber goby Elacatinus figaro: histopathological and imunohistochemical diagnosis

As micobacterioses afetam várias espécies de peixes, tanto comerciais como ornamentais. É uma enfermidade sistêmica com formação de granulomas, conhecida como micobacteriose de peixes. O desenvolvimento da aquicultura tem aumentado o número de casos com essa enfermidade que muitas vezes é de difícil diagnóstico. Neste trabalho apresentamos dois casos de micobacterioses em Paralichthys orbignyanus e Elacatinus figaro provenientes do Laboratório de Piscicultura Estuarina e Marinha da Universidade Federal do Rio Grande (FURG). As micobactérias de peixes possuem menos ácidos graxos que as de mamíferos, por isso foi utilizado o protocolo de coloração de Fite-Faraco, uma vez que o protocolo de coloração clássico de Ziehl Neelsen pode resultar em falsos negativos. Para determinar o tipo de micobactéria foi utilizada a imuno-histoquímica com a qual se pode diagnosticar a presença de Mycobacterium marinum. A enfermidade pode ser transmitida para o homem e com esse trabalho ressalta-se a necessidade de fazer o diagnóstico correto e implantar medidas de proteção para as pessoas que estão em contato com os peixes infectados.

Mycobacteriosis affects various species of fish, including those cultured with commercial purposes. It is a chronic systemic with granuloma forming disease known as fish mycobacteriosis. In the last few years the interest of fish culture has been increasing due to the reduction of the natural fish stocks. However the intensification of fish culture has collaborated to the development of diseases such as mycobacteriosis, causing losses due to the chronic characteristics and difficult diagnosis. This study is to report two cases of mycobacteriosis observed at "Laboratório de Piscicultura Estuarina e Marinha of the Universidade Federal do Rio Grande (FURG)", one for Brazilian flounder Paralichthys orbignyanus and another for barber goby Elacatinus figaro. The Fite-Faraco staining protocol was used. Membranes of mycobacterial cells contain a waxy substance composed of mycolic acids. These are ß-hydroxy carboxylic acids with chain lengths of up to 90 carbon atoms. The property of acid fastness is related to the carbon chain length of the mycolic acid found in any particular species. The fish mycobacterium is much less acid and alcohol fast than the tubercle bacillus and the classic Ziehl-Neelsen Staining Protocol may give false results. The presence of mycobacterial antigen lesions was studied by immunohistological methods using monoclonal antibodies to Mycobacterium marinum. Humans may be infected by these bacteria and develop cutaneous granuloma. In this paper the necessity is stressed for a correct diagnosis of the disease, contributing to the prevention of its establishment in aquatic facilities, and thus, preserving cultured fish as well as human beings from infection.

Diversos enfoques sobre la situacion del rio Reconquista;una vision desde la fisicoquimica:lo que se sabe y lo que no se sabe

La cuenca del rio Reconquista evidencia, tal como lo demuestran estudios quimicos y tests biologicos de diversas investigaciones,un alto grado de contaminacion,en especial luego del ingreso de arroyos provenientes de sectores urbanos y parques industriales.El trabajo presenta diversas visiones y enfoques acerca de este problema y sus consecuencias

Diversos enfoques sobre la situacion del rio Reconquista;una vision desde la fisicoquimica:lo que se sabe y lo que no se sabe

La cuenca del rio Reconquista evidencia, tal como lo demuestran estudios quimicos y tests biologicos de diversas investigaciones,un alto grado de contaminacion,en especial luego del ingreso de arroyos provenientes de sectores urbanos y parques industriales.El trabajo presenta diversas visiones y enfoques acerca de este problema y sus consecuencias

Estudio de las caracteristicas bioecologicas del lago San roque, Villa Carlos Paz, provincia de Cordoba. Parte III: bioindicadores hematologicos e inmunologicos de contaminacion en peces

Los bioindicadores representan marcadores puntuales y selectos de stres para todos los niveles de la organizacion biologicas,permitiendo evaluar y predecir los efectos de las modificaciones ambientales antes que el daño sea irreversible.Los bioindicadores histologicos,inmunologicos,hematologicos,bioquimicos y moleculares se encuentran en los marcadores mas importantes.El trabajo analiza bioindicadores hematologicos e inmunologicos en dos especies de peces del lago San Roque.Las partes i y II de este articulo fueron publicados en los Nº 37 y 38 de dicha revista

Estudio de las caracteristicas bioecologicas del lago San roque, Villa Carlos Paz, provincia de Cordoba. Parte III: bioindicadores hematologicos e inmunologicos de contaminacion en peces

Los bioindicadores representan marcadores puntuales y selectos de stres para todos los niveles de la organizacion biologicas,permitiendo evaluar y predecir los efectos de las modificaciones ambientales antes que el daño sea irreversible.Los bioindicadores histologicos,inmunologicos,hematologicos,bioquimicos y moleculares se encuentran en los marcadores mas importantes.El trabajo analiza bioindicadores hematologicos e inmunologicos en dos especies de peces del lago San Roque.Las partes i y II de este articulo fueron publicados en los Nº 37 y 38 de dicha revista

Distúrbios inmunológicos, inmunodefiencia y sarcoma angioblástico de tipo Kaposi: aspectos lesionales en los ganglios linfáticos / Immunological disorders, immunodeficiency and angioblastic sarcoma of Kaposis type: lesional aspects in the lymph nodes

Se describen los cambios hitológicos en los ganglios linfáticos en pacientes con evidencias de inmunodeficiencia y sarcoma angioblástico de tipo Kaposi, destacando las modificaciones previas y concomitantes a la instalación de la neoplasia y relacionando las mismas con el disturbio inmunológico. Se realizan consideraciones sobre la histogénesis de las células neoplásicas en los angiosarcomas de tipo Kaposi y se concluye que las mismas muestran caracteres hemangiopericitoides y endoteliales combinados (AU)

Distúrbios inmunológicos, inmunodefiencia y sarcoma angioblástico de tipo Kaposi: aspectos lesionales en los ganglios linfáticos / Immunological disorders, immunodeficiency and angioblastic sarcoma of Kaposis' type: lesional aspects in the lymph nodes

Se describen los cambios hitológicos en los ganglios linfáticos en pacientes con evidencias de inmunodeficiencia y sarcoma angioblástico de tipo Kaposi, destacando las modificaciones previas y concomitantes a la instalación de la neoplasia y relacionando las mismas con el disturbio inmunológico. Se realizan consideraciones sobre la histogénesis de las células neoplásicas en los angiosarcomas de tipo Kaposi y se concluye que las mismas muestran caracteres hemangiopericitoides y endoteliales combinados