Fatty acids as trophic biomarkers in vitellogenic females in an impounded tropical river

Fatty acids have been used in marine biogeochemistry as food chain biomarkers, but in freshwater these studies are rare. In order to evaluate the fatty acid potential as biomarkers in freshwater, their profile was analyzed during vitellogenesis in two fish species, in both waterfall and reservoir environments of the Paraiba do Sul River Basin. Detrivorous Hypostomus affinis and omnivorous Geophagus brasiliensis seem to elongate and desaturate polyunsaturated fatty acids (PUFA) and transfer them to the ovaries` phospholipids. Waterfall Geophagus brasiliensis have more highly unsaturated fatty acids in the liver, but in the reservoir, accumulation mainly occurs in muscle and ovary triglycerides, suggesting trophic opportunism and a plasticity during vitellogenesis. In Hypostomus affinis, PUFA alteration occurs only in the reservoir, suggesting a high phytoplankton occurrence. Eutrophication and water speed is reflected in Hypostomus affinis ovaries by higher PUFAn3 and bacterial fatty acids. As in marine environments, analysis of mono- and polyunsaturated fatty acids during vitellogenesis can be used as a tool in food chain studies in freshwater.

Patterns of oocyte development in natural habitat and captive Salminus hilarii Valenciennes, 1850 (Teleostei: Characidae)

Fecundity and oocyte development in Salminus hilarii female brood stock were analyzed with the aim of investigating the impact of migration impediment on oogenesis. Histological analyses of the ovaries were performed in adult females caught in two different environments-the TietA(a) River (natural) and captivity-and the gonadossomatic index, oocyte diameter and fecundity determined. Five germ cell development stages (oogonium, perinucleolar, cortical alveoli, vitellogenic, ripe) and two other structures (postovulatory follicles and atretic oocytes) were observed in females caught in the river. Captive animals lacked the ripe oocytes and postovulatory follicles and had a relatively higher number of atretic oocytes. Females in captivity are known to produce larger oocytes, and they release fewer eggs in each spawn (absolute fecundity) when compared with animals that are able to migrate. Our results suggest that the TietA(a) River is undergoing alterations which are being reflected in the reproductive performance of S. hilarii, mainly due to the presence of atretic oocytes in females caught in the river. The lack of postovulatory follicles and ripe oocytes in captive animals reveals that migratory impediment negatively impacts final oocyte maturation. However, the stage of maturation reached is adequate for ovulation induction with hormone manipulation.

Immunocytochemical identification of adenohypophyseal cells in the pirarucu (Arapaima gigas), an Amazonian basal teleost

The adenohypophysis (AH) of juvenile pirarucu (Arapaima gigas), a representative species of the Osteoglossomorpha (bonytongue fishes, one of the oldest living groups of the teleosts), was studied using histochemical and immunocytochemical methods. The AH is comprised of the pars distalis (PD), without a clear distinction between rostral pars distalis (RPD) and proximal pars distalis (PPD), and the pars intermedia (PI). The neurohypophysis (NH) is positioned on top of the PD and penetrates and branches into the PI. In the most rostral dorsal portion of the PD, adrenocorticotropic cells and fusiform gonadotropic cells were found. In the central PD, scarce prolactin-producing cells and growth-hormone-producing cells were located mainly in the dorsal part, whereas round gonadotropic cells were abundant in the ventral portion of this region. Human thyrotropin immunoreactive cells were not found in the entire AH. In the PI, melanotropic, some adrenocorticotropic, and somatolactin-producing cells were located intermingled surrounding the neurohypophyseal branches. Our results showed that the A. gigas pituitary has some basal characteristics between the ancient Actinopterygii and the more derived teleosts.

Comparison of fatty acid composition in nine organs of the sympatric Antarctic teleost fish species Notothenia coriiceps and Notothenia rossii (Perciformes: Nototheniidae)

Fatty acid (FA) composition of nine organs from two closely related Antarctic fish species, Notothenia codiceps and Notothenia rossii, was determined through gas chromatography with flame ionization detection. A data set for each species was obtained using major FA profiles from specimens caught in the sea waters of Admiralty Bay during the summer season. The FA profiles for both species are overall similar, but organ peculiarities have been found, which could reflect metabolic specificities and feeding habits between species. With the exception of liver, the most abundant FA in organs was the n-3 polyunsaturated FA. The total n-6 polyunsaturated FAs were minor components in all evaluated organs. Palmitic acid was identified as the major saturated FA, whereas oleic acid was the most represented of the monounsaturated FA in almost all assessed organs of both species. The n-3/n-6 ratios of all organs were higher than 3.5. Differences in individual FA and FA metabolic profiles of some organs observed between N. coriiceps and N. rossii suggest specific requirements in the mobilization, transport, incorporation, and/or catabolism of lipids that were reinforced by differences on some FA ratios expressing the activity coefficient of enzymes implicated on the FA pathway flux. (C) 2009 Elsevier Inc. All rights reserved.

Isolation and characterization of Flavobacterium columnare (Bernardet et al. 2002) from four tropical fish species in Brazil

Flavobacterium columnare is the causative agent of columnaris disease in freshwater fish, implicated in skin and gill disease, often causing high mortality. The aim of this study was the isolation and characterization of Flavobacterium columnare in tropical fish in Brazil. Piracanjuba (Brycon orbignyanus), pacu (Piaractus mesopotamicus), tambaqui (Colossoma macropomum) and cascudo (Hypostomus plecostomus) were examined for external lesions showing signs of colunmaris disease such as greyish white spots, especially on the head, dorsal part and caudal fin of the fish. The sampling comprised 50 samples representing four different fish species selected for study. Samples for culture were obtained by skin and kidney scrapes with a sterile cotton swabs of columnaris disease fish and streaked onto Carlson and Pacha (1968) artificial culture medium (broth and solid) which were used for isolation. The strains in the liquid medium were Gram negative, long, filamentous, exhibited flexing movements (gliding motility), contained a large number of long slender bacteria and gathered into ‘columns'. Strains on the agar produced yellow-pale colonies, rather small, flat that had rhizoid edges. A total of four Flavobacterium columnare were isolated: 01 Brycon orbignyanus strain, 01 Piaractus mesopotamicus strain, 01 Colossoma macropomum strain, and 01 Hypostomus plecostomus strain. Biochemical characterization, with its absorption of Congo red dye, production of flexirubin-type pigments, H2S production and reduction of nitrates proved that the isolate could be classified as Flavobacterium columnare.

Elaboration of sausage using minced fish of Nile tilapia filleting waste

The objective of this study was to evaluate the inclusion of minced fish (MF) (0, 20, 40, 60, 80 and 100%), obtained from Nile tilapia filleting waste, in sausage and determine their physicochemical, nutritional and sensory properties. The sausages showed a decrease in protein and increase in fat content with increasing inclusion of MF. The nutritional quality of the products was high, with digestibility over 85%. The parameters of texture instrumental and yellow color (b*) decreased with the increasing inclusion of MF. The sensory evaluation of the color showed that the maximum level of inclusion of MF was not well accepted by the panelists. The sausage with the best acceptance for the flavor attribute was those with 60% of MF. The results showed good nutritional quality of sausages utilizing MF of Nile tilapia filleting waste and according to the sensory evaluation, the maximum level of inclusion should not exceed 60%.

Mechanisms of pigmentation loss in subterranean fishes

Troglobitic (exclusively subterranean) organisms usually present, among their apomorphies related to the subterranean life (troglomorphisms), the regression of eyes and melanic pigmentation. The degree of regression varies among species, from a slight reduction to the complete loss of eyes and dark pigmentation, without a taxonomic correlation. While mechanisms of eye reduction have been intensively investigated in some troglobites such as the Mexican blind tetra characins, genus Astyanax, and the European salamander, Proteus anguinus, few studies have focused on pigmentation. The Brazilian subterranean ichthyofauna distinguishes not only by the species richness (23 troglobitic fishes so far known) but also by the variation in the degree of reduction of eyes and pigmentation. This study focused on Brazilian fishes completely devoid of melanic pigmentation: the characiform Stygichthys typhlops (Characidae) and the siluriforms Ancistrus formoso (Loricariidae), Rhamdiopsis sp.1 (Heptapteridae; from caves in the Chapada Diamantina, Bahia) and Rhamdiopsis sp. 2 (cave in Campo Formoso, Bahia). In order to investigate if such depigmentation is the result of blockage in some step in the melanogenesis, in vitro tests of administration of L-DOPA were done, using caudal-fin fragments extracted from living fish. Except for Rhamdiopsis sp. 2, all the studied species were DOPA(+), i.e., melanin was synthesized after L-DOPA administration. This indicates these fish do have melanophores but they are unable to convert L-tyrosine to L-DOPA. On the other hand, Rhamdiopsis sp. 2, like the albino specimens of Trichomycterus itacarambiensis previously studied (which correspond to one third of the population), are DOPA(-), either because the block of melanin synthesis occurs downstream in melanogenesis, which is probably the case with T. itacarambiensis (monogenic system in view of the phenotypic discontinuity), or because the so-called albinos do no possess melanophores. The physiological loss in the ability to synthesize melanin, apparently caused by different genetic processes in DOPA(+) and in DOPA(-) fishes, may co-exist in subterranean populations with a decrease in the density of melanophores, as observed in the pigmented two thirds of T. itacarambiensis population, a morphological reduction apparently controlled by polygenic systems producing a continuous phenotypic variation.

Use of chromosome microdissection in fish molecular cytogenetics

Chromosome microdissection is a technique in which whole chromosomes or chromosomal segments are dissected under an inverted microscope yielding chromosome-specific sequences. Several protocol modifications introduced during the past 15 years reduced the number of chromosomes required for most applications. This is of particular interest to fish molecular cytogenetics, since most species present highly uniform karyotypes which make impossible the collection of multiple copies of the same chromosome. Probes developed in this manner can be used to investigate chromosome homologies in closely related species. Here we describe a protocol recently used in the gymnotiform species group Eigenmannia and review the major steps involved in the generation of these markers focusing on protocol modifications aiming to reduce the number of required chromosomes.

Systematics of the neotropical fish subfamily Glandulocaudinae (Teleostei: Characiformes: Characidae)

The systematics of the Glandulocaudinae is reviewed in detail and justification for the recognition of the group as a subfamily is discussed. The subfamily Glandulocaudinae consists of three genera: Lophiobrycon with one species plesiomorphic in some anatomical features but some others exclusively derived relative to the species in the other genera; Glandulocauda with two species intermediate in phylogenetic derivation; and Mimagoniates with seven species (one new), all more phylogenetically derived concerning their pheromone producing caudal-fin organs and with other anatomical characters presumably more derived than in the species of the other genera. Glandulocauda melanogenys Eigenmann, 1911, is considered a junior synonym of Hyphessobrycon melanopleurus Ellis, 1911. A replacement name, Glandulocauda caerulea Menezes & Weitzman, is proposed for G. melanopleura Eigenmann, 1911. Gland cells found in the caudal-fin organs of all species are histologically indistinguishable from club cells and probably secrete a pheromone during courtship. The club cells are associated with somewhat modified to highly derived caudal scales forming a pheromone pumping organ in the more derived genera and species. This subfamily is distributed in freshwaters of eastern and southern Brazil, Paraguay, and northeastern Uruguay.

Spatial and temporal distribution of fish in Palmas bay, Ubatuba, Brazil

The aim of this study was to analyze the distribution and abundance of the fish fauna of Palmas bay on Anchieta Island in southeastern Brazil. Specimens were caught in the summer and winter of 1992, using an otter trawl at three locations in the bay. The specimens were caught in both the nighttime and daytime. Data on the water temperature and salinity were recorded for the characterization of the predominant water mass in the region, and sediment samples were taken for granulometric analysis. A total of 7 656 specimens (79 species), with a total weight of approximately 300 kg, were recorded. The most abundant species were Eucinostomus argenteus, Ctenosciaena gracilicirrhus, Haemulon steindachneri, Eucinostomus gula and Diapterus rhombeus, which together accounted for more than 73% of the sample. In general, the ecological indices showed no differences in the composition of species for the abiotic variables analyzed. The multivariate analysis showed that the variations in the distribution of the fish fauna were mainly associated with intra-annual differences in temperature and salinity, resulting from the presence of South Atlantic Central Water (SACW) in the area during the summer. The analysis also showed an association with the type of bottom and a lesser association with respect to the night/day periods.

The ichthyofauna of upper rio Capivari: defining conservation strategies based on the composition and distribution of fish species

Although the rio Capivari basin is recognized as an area of great importance for the ichthyofauna, it lacks virtually every basic requirement for the definition of appropriate conservation strategies, since not even its species composition is known. The objective of this work is to determine the composition and distribution of fish species in the upper rio Capivari basin, relating them to the local physical features, and to evaluate the effectiveness of proposed conservations units, delimited based on areas of native vegetation remains, on the conservation of local ichthyofauna. During 2007, 50 different watercourses were sampled with gillnets, cast nets and kick nets. A total of 1308 individuals belonging to 41 species were captured. Degree of conservation, altitude and width were the parameters that best explained fish species richness. Considering the recently proposed boundaries for potential conservation units in the region only 15 or 20 out of 41 species would be found in the State Park and Environmental Protection Area respectively. In practice, the proposed conservation units would not be effective tools for fish conservation, since it would be located in mountainous areas of high altitude, of headwaters streams and where few species are found. In such context, the conservation of specific stretches of larger rivers is critical.

On the name of the lepidophagous characid fish Roeboexodon guyanensis (Puyo) (Teleostei: Characiformes: Characidae)

The arguments for the usage of the names Gnathoplax, Roeboexodon, R. geryi, and R. guyanensis are revised. Based on the literature and museum specimens, we recommend that the neotype of Exodon guyanensis should be considered valid; that the genus Gnathoplax should be considered an objective junior synonym of Roeboexodon; and that Roeboexodon geryi should be considered an objective junior synonym of Exodonguyanensis.

Histopathological, immunohistochemical and ultraestructural evaluation of inflammatory response in Arius genus fish under experimental inoculation of BCG

The aim of this study was to evaluate the inflammatory response kinetics after experimental inoculation with BCG in the primitive Arius sp. fish. The BCG was applied through the intramuscular injection in the caudal peduncular region, and the samples were collected for the analyses at days 1, 3, 7, 14, 21, and 33 post-injection. Acute phase inflammatory infiltrate was characterized by the predominant mononuclear cells, intersticial edema, and muscular tissue necrosis. As the inflammatory response evolved, a large number of multinuclear giant cells were formed containing the BCG. These giant cells were positive for the S100 protein at the histochemical analysis, which demonstrate the macrofage activity, confirmed by the ultra-structural analysis showing the lack of the cytoplasmic membrane enveloping the many nuclei within the giant cell. These results led to the conclusion that Arius sp. fish injected with the BCG showed a difuse inflammatory response characterized by a large number of mononuclear cells, absence of granuloma formation, and predominant giant cells.

Effect of n-3 polyunsaturated fatty acids on oxidative stress in rats supplemented with different doses of fish oil

The diet and plasma lipid patterns associated with lipid oxidation susceptibility in rats fed different doses of polyunsaturated fatty acids (n-3 PUFA) from fish oil were evaluated. Wistar rats were assigned into three groups and received diets containing 8% soybean oil (SOY), 4% soybean oil + 4% fish oil (SOY-FISH) and 8% fish oil (FISH) for 21 days. Linoleic, oleic and ?-linolenic acids in SOY diets were substituted by myristic, palmitic, palmitoleic, eicosapentaenoic (EPA) and docosahexaenoic (DHA) acids in SOY-FISH and FISH diets reducing the n-6/n-3 ratio and increasing the peroxidability index (PI). Increased dietary EPA and DHA were observed in SOY-FISH and FISH plasma at the expense of linoleic and arachidonic acid levels. Saturated fatty acids, which were significantly different between the three diets (P < 0.01), were found at the same concentration in the plasma (P = 0.23). No changes were observed in oxidative stress as measured by the concentration of thiobarbituric acid reactive substances (TBARS) expressed in brain homogenates. However, TBARS concentration in the plasma of the SOY-FISH group was higher than the other two groups (P = 0.02). The major differences between these three groups were the n-3 PUFA content (0.4, 1.8 and 3.2 g/100 g diet) and the saturates/polyunsaturates ratio (0.3, 0.5 and 0.8) for SOY, SOY-FISH, and FISH groups, respectively. Thus, n-3 PUFA intake from fish oil only when followed by a decrease in saturated/polyunsaturated fatty acids ratio increased oxidative susceptibility in rats measured by plasma TBARS concentration

Development, implementation, and assessment of a distance module in endocrine physiology

Rangel EM, Mendes IA, Carnio EC, Marchi Alves LM, Godoy S, Crispim JA. Development, implementation, and assessment of a distance module in endocrine physiology. Adv Physiol Educ 34: 70-74, 2010; doi: 10.1152/advan.00070.2009.-This study aimed to develop, implement, and assess a distance module in endocrine physiology in TelEduc for undergraduate nursing students from a public university in Brazil, with a sample size of 44 students. Stage 1 consisted of the development of the module, through the process of creating a distance course by means of the Web. Stage 2 was the planning of the module's practical functioning, and stage 3 was the planning of student evaluations. In the experts' assessment, the module complied with pedagogical and technical requirements most of the time. In the practical functioning stage, 10 h were dedicated for on-site activities and 10 h for distance activities. Most students (93.2%) were women between 19 and 23 yr of age (75%). The internet was the most used means to remain updated for 23 students (59.0%), and 30 students (68.2%) accessed it from the teaching institution. A personal computer was used by 23 students (56.1%), and most of them (58.1%) learned to use it alone. Access to a forum was more dispersed (variation coefficient: 86.80%) than access to chat (variation coefficient: 65.14%). Average participation was 30 students in forums and 22 students in the chat. Students' final grades in the module averaged 8.5 (SD: 1.2). TelEduc was shown to be efficient in supporting the teaching- learning process of endocrine physiology.