Diversidade Ictiofaunística e Ecologia reprodutiva de uma espécie nativa de peixe da Bacia Piranhas-Assu, RN

The Caatinga biome is rich in endemic fish species fauna. The present study the results of fish faunal surveys conducted in the hydrographic basin of Piranhas-Assu of the Brazilian Caatinga biome. The fish samples collected were distributed in four orders (Characiformes, Perciformes, Siluriformes and Synbranchiformes), 11 families (Characidae, Curimatidae, Auchenipteridae, Anostomidae, Prochilodontidae, Erythrinidae, Cichlidae, Sciaenidae, Heptapteridae, Loricariidae, Synbranchidae) and 22 species, of which 17 are endemic and five have been introduced from other basins. The order Characiformes was the most representative in number of species (46,35% ) followed by Perciformes (35,38%), Siluriformes (17,44%) and Synbranchiformes (0,5%). The Nile tilapia, Oreochomis niloticus, the only exotic species, was most expressive in number of individuals (24.92%) followed by the native species piau preto, Leporinus piau (18,77 %). Considering the relative frequency of occurrence of the 22 species, 13 were constant, five were accessory and four were occasional. This study investigated the reproductive ecology of an endemic fish black piau, Leporinus piau from the Marechal Dutra reservoir, Acari, Rio Grande do Norte. Samplings were done on a monthly basis from January to December 2009, and a total of 211 specimens were captured. The environmental parameters such as rainfall, temperature, pH, electrical conductivity and dissolved oxygen of water were recorded. The sampled population showed a slight predominance of males (55%), however females were larger and heavier. Both sexes of L. piau showed positive allometric growth, indicating a higher increase of weight than length. The first sexual maturation of males occurred at smaller size, with 16.5 cm in total length than females (20.5 cm). During the reproductive period, the condition factor and gonadosomatic index (GSI) of L. piau were negatively correlated. This species has large oocytes with a high mean fecundity of 54.966 with synchronous oocyte development and total spawning

Biologia reprodutiva da |Tainha, Mugil curema valencientes, 1836 (osteichthyes: mugilidade) nas águas costeiras do Rio Grande do Norte

The marine fish white mullet, Mugil curema Valenciennes, 1836 (Osteichthyes: Mugilidae) exhibits a wide geographical distribution, being common in the Brazilian coast and is an important component of the artisanal fisheries. The objective of this study was to investigate the reproductive biology of M. curema in the coastal waters of Rio Grande do Norte. Fish samples were captured on a monthly basis during August, 2008 to July, 2009. The fish specimens were numbered, weighed, measured, dissected and their gonads were removed, weighed, their sex and gonadal development were identified. The length-weight relationship was determined for males and females. The sex ratio, the size at first gonadal maturation and gonadosomatic index (GSI) were calculated and ovarian development was investigated using macroscopic and histological techniques. The fecundity, spawning type and the reproductive period of the species were determined. A total of 366 specimens (186 males and 180 females) were captured. The sex ratio was 1:1 and the females were heavier than males. The estimated values of the angular coefficient for both sexes suggest that the species has isometric growth. The size at which 50% of the population began the process of maturation was 25.9 cm of total length for grouped sex. The macroscopic characteristics of the ovaries showed four stages of development: immature, maturing, mature and spent. However, the microscopic characteristics of the ovaries showed five stages of development: immature, early maturing, late maturing, mature and spent. The development of oocytes indicated five phases: Chromatin-nucleolus (phase I), initial perinucleolar (phase II), final perinuclear (phase II), formation of vitelline vesicle or yolk (phase III), vitellogenic (phase IV) and complete vitellogenesis (phase V). The species has a prolonged spawning period, with two peaks coinciding with the rainy season.

Dinâmica reprodutiva e parasitária de quatro espécies de peixes das águas costeiras do Sudoeste do Oceano Atlântico, Brasil

The present study investigated the reproductive dynamics and parasitism of four species of marine fishes: serra Spanish mackerel, Scomberomorus brasiliensis, Atlantic leatherjacks, Oligoplites saurus and O. palometa,, and Atlantic bumper, C. chrysurus, during the period of August, 2005 to July, 2007, in the coastal waters of Southwest Atlantic Ocean, Brazil. The collected fish samples were measured, weighed, dissected, the gonads were weighed and examined to separate the sex. The gonadosomatic index (GSI), fecundity, type of spawning, the breeding season, the macro and microscopic characterization of the gonads were determined. The ectoparasites from the branchial chambers and bucal cavity of the fish were collected, measured, weighed and identified. The sex ratio of the study fish species were approximately 1M:1F, however, there was a predominance of males of O. palometa (3M:2F). The GSI of fishes varied according to their reproductive cycle and the stage of gonadal maturation. The highest values of GSI and the spawning period coincided with the rainy period of the region. The females presented total spawning and the fecundity was positively correlated with the weight of the ovary and the body. Four stages of development of the gonads immature, maturing, mature and spent were identified macroscopically and histological analyses of ovaries revealed the different phases of oocyte development. Three species of isopod parasites were identified in the study fishes: Livoneca redmmanni, Rocinela signata and Cimothoa spinipalpa. The first two species occurred in the branchial cavities of C. chrysurus and S. brasiliensis. The isopod C.spinipalpa (a new species) was registered for the first time in the bucal cavity of O. saurus and O. palometa. The parasitic isopods preferred the branchial chambers and the bucal cavity of the host fishes as these were protected microhabitats. The isopods parasitized the immature, maturing and mature fishes. The prevalence of infection of isopods in the hosts varied from 16 to 21%, though in O. palometa it was 60%. In the rainy period the highest isopod parasitic occurrence was registered, however, this did not prejudice the normal reproductive cycle of the host fish.

Participação da neurotransmissão dopaminergica no efeito hiperlocomotor do neuropeptideo S

Neuropeptide S (NPS) is an endogenous 20-aminoacid peptide which binds a G protein-coupled receptor named NPSR. This peptidergic system is involved in the modulation of several biological functions, such as locomotion, anxiety, nociception, food intake and motivational behaviors. Studies have shown the participation of NPSR receptors in mediating the hyperlocomotor effects of NPS. A growing body of evidence suggests the participation of adenosinergic, dopaminergic and CRF systems on the hyperlocomotor effects of NPS. Considering that little is known about the role of dopaminergic system in mediating NPS-induced hyperlocomotion, the present study aims to investigate the locomotor actions of intracerebroventricular (icv) NPS in mice pretreated with α-metil-p-tirosine (AMPT, inhibitor of dopamine synthesis), reserpine (inhibitor of dopamine vesicle storage) or sulpiride (D2 receptor antagonist) in the open field test. A distinct group of animals received the same pretreatments described above (AMPT, reserpine or sulpiride) and the hyperlocomotor effects of methylphenidate (dopamine reuptake inhibitor) were investigated in the open field. NPS and methylphenidate increased the mouse locomotor activity. AMPT per se did not change the locomotion of the animals, but it partially reduced the hyperlocomotion of methylphenidate. The pretreatment with AMPT did not affect the psychostimulant effects of NPS. Both reserpine and sulpiride inhibited the stimulatory actions of NPS and methylphenidate. These findings show that the hyperlocomotor effects of methylphenidate, but not NPS, were affected by the pretreatment with AMPT. Furthermore, methylphenidate- and NPS-induced hyperlocomotion was impaired by reserpine and sulpiride pretreatments. Together, data suggests that NPS can increase locomotion even when the synthesis of catecholamines was impaired. Additionally, the hyperlocomotor effects of NPS and methylphenidate depend on monoamines vesicular storaged, mainly dopamine, and on the activation of D2 receptors. The psychostimulant effects of NPS via activation of dopaminergic system display clinical significance on the treatment of diseases which involves dopaminergic pathways, such as Parkinson s disease and drug addiction