Sanitary conditions of the Goliath grouper Epinephelus itajara in captivity on estuarine environment: case report / Condições sanitárias do mero Epinephelus itajara em cativeiro em ambiente estuarino: relato de caso

This study aimed to report the sanitary conditions through the hematological analysis of grouper E. itajara reared in captivity on estuarine conditions. Seven Goliath groupers (1,881.5±1,246.03g) were captured and kept in two tanks located on estuary. After 20 days, fish were collected for morphologic and hemato-physiologic evaluation. Two fish had clinical signs such as hemorrhagic spots and loss of scale due to agonistic behavior. Blood samples were collected, and the hematological parameters (biochemical, erythrogram and leukogram) were determined. Blood cells were characterized by their size, color and shape. Univariate statistic and principal components analysis were used to identify a hematological standard between fish with or without clinical signs. Four leukocyte types were found: lymphocyte, monocyte, neutrophil and basophil. Regardless of the clinical signs the cell morphology did not present any difference among the fish. However, there is a significant correlation between erythrocyte and lactate on fish with clinical signs. Thus, agonistics encountered among the fish is a stressing factor in captivity conditions making it necessary to have adequate management related to the size of fish and stocking density.(AU)

Este estudo avaliou as condições sanitárias do peixe mero E. itajara mantido sob cativeiro, em condições estuarinas, pelas análises hematológica e morfológica. Sete peixes (1.881,5±1.246,03g) foram capturados e mantidos em tanques localizados no estuário. Após 20 dias, os peixes foram coletados para avaliações morfológica e hematológica. Dois peixes tiveram sinais clínicos, como manchas hemorrágicas e perda de escamas devido ao comportamento agonístico entre os peixes. Amostras sanguíneas foram coletadas dos peixes anestesiados com auxílios de seringas umedecidas com EDTA 3%. Determinaram-se os parâmetros hematológicos (bioquímico, eritrograma e leucograma). Células sanguíneas foram caracterizadas por seu tamanho, cor e padrão. Estatística univariada e análises de componentes principais foram usadas para identificar um padrão hematológico entre os peixes com e sem sinais clínicos. Quatro tipos de leucócitos foram encontrados: linfócito, monócito, neutrófilo e basófilo. Os sinais clínicos não apresentaram diferença entre os peixes e a morfologia celular. Contudo, observou-se uma correlação entre os peixes com sinais clínicos e a quantidade de eritrócitos e lactato. Assim, encontros antagônicos entre os peixes são um fator estressante em condições de cativeiro, tornando-se necessário um manejo mais adequado relacionado ao tamanho dos indivíduos e à densidade de estocagem.(AU)

Efficacy of Ocimum gratissimum essential oil against the monogenean Cichlidogyrus tilapiae gill parasite of Nile tilapia / Eficácia do óleo essencial de Ocimum gratissimum contra o monogenea Cichlidogyrus tilapiae parasita de brânquias de tilápia-do-nilo

The phythotherapy is an alternative to use of chemotherapeutical agents against monogenean infection. This study evaluated the anthelmintic activity of essential oil Ocimum gratissimum against monogenean Cichlidogyrus tilapiae as well as its acute toxicity in tilapia juveniles. The mean lethal concentration (LC50) and different concentrations of the essential oil, both in vitro and in vivo assays (short and long-term baths) were assessed. The LC50 was 40.70mg.L-1 and in the in vitro assay this concentration showed 80% efficacy at the last two hours and in the in vivo assay 65.87% efficacy in long-term bath. However, it provoked morphological alterations on the gills such as hyperplasia and edema. The parasites exposure at the highest concentration (320mg.L-1) showed 100% mortality after 2h exposure in the in vitro assay, whereas in the in vivo assay, short-term baths of 5min for 3 consecutive days showed an efficacy of 87.71% without gills damage. These results demonstrate the anthelminthic activity of essential oil O. gratissimum and the safety concentration to use in Nile tilapia.(AU)

A fitoterapia é uma alternativa ao uso de agentes químicos contra infecções por parasitos monogenéticos. Este estudo avaliou a atividade anti-helmíntica do óleo essencial Ocimum gratissimum contra o monogenea Cichlidogyrus tilapiae , bem como sua toxicidade aguda e histopatologia em juvenis de tilápias. Foram avaliadas a concentração letal média (CL50) e diferentes concentrações de óleo essencial, tanto in vitro como in vivo (banho de curta e longa duração). A CL50 foi de 40,70mg.L-1; no ensaio in vitro, essa concentração apresentou 80% de eficácia, e no ensaio in vivo 65,87% de eficácia em banho de exposição crônica. No entanto, provocou alterações morfológicas nas brânquias, como hiperplasia e edema. A exposição dos parasitas na concentração mais elevada (320mg.L-1) mostrou 100% de mortalidade após duas horas de exposição no ensaio in vitro, enquanto no ensaio in vivo, em banho de curta duração de cinco minutos, durante três dias consecutivos, apresentou uma eficácia de 87,71%, sem danos às brânquias. Esses resultados demonstraram a atividade anti-helmíntica do óleo essencial de O. gratissimum e a concentração de segurança para uso na tilápia-do-nilo em banhos de curta duração.(AU)

Fish sperm subpopulations: Changes after cryopreservation process and relationship with fertilization success in tambaqui (Colossoma macropomum).

Fish tambaqui (Colossoma macropomum) is the native Brazilian fish with the highest agricultural production under intensive aquaculture in South America. However, the decrease in the genetic variability in fish farms has become necessary the improvement of cryopreservation process through new statistical studies of spermatozoa (like subpopulation studies). The evaluation of the kinetic data obtained with a computer-assisted sperm analysis system, applying a two-step cluster analysis, yielded in tambaqui three different subpopulations in fresh sperm: SP1, considered as a slow nonlinear subpopulation; SP2, considered as a fast nonlinear subpopulation, and finally; SP3, considered as a fast linear subpopulation. For cryopreserved sperm, the cluster analysis yielded only two sperm subpopulations: SP1', considered as a slow nonlinear subpopulation and SP2', which seemed to be an intermediate subpopulation (showing medium motility and velocity values) merged from SP2 and SP3 obtained from fresh sperm. Coefficients of correlation (r) and determination (r2) between the sperm subpopulations from fresh sperm and the fertilization rates were calculated, and SP2 and SP3 (the fast-spermatozoa subpopulations) showed a high-positive correlation with the fertilization rates (r = 0.93 and 0.79, respectively). In addition, the positive significant correlations found in curvilinear velocity (r = 0.78), straight line velocity (r = 0.57), and average velocity (r = 0.75) indicate that sperm kinetic features seem to be a key factor in the fertilization process in tambaqui, as occur in other fish species.

Standardization of European eel (Anguilla anguilla) sperm motility evaluation by CASA software.

The development of powerful computer-assisted sperm analysis software has made kinetic studies of spermatozoa possible. This system has been used and validated for several species, but some technical questions have emerged regarding fish sample evaluations (i.e., frame rate, sperm dilution, chamber model, time of analysis, magnification lens, etc.). In the present study, we have evaluated the effects of different procedural and biological settings with the aim to correctly measure sperm quality parameters of the European eel. The use of different chambers did not affect the sperm motility parameters. However, regarding lens magnification, 10× was the most accurate lens, showing the least variation in the acquired data. Similarly, the frame rate setting resulted in a dramatic effect in some sperm kinetic parameters, primarily in terms of curvilinear velocity; we therefore recommend using the camera's highest available frame rate setting. Finally, the reduction in sperm motility over postactivation times suggests that sperm analysis should be performed within the first 60 seconds after activation of the European eel sperm. In conclusion, some protocol variables of sperm analysis by computer-assisted sperm analysis software can affect the measurement of eel sperm quality parameters, and should be considered before directly comparing results obtained by different laboratories. Moreover, because marine fish species show relatively similar features of sperm kinetic parameters, these results could be considered in the evaluation of the motility of sperm from other fish species.

Cryopreservation of tambaqui (Colossoma macropomum) semen: extenders, cryoprotectants, dilution ratios and freezing methods.

The tambaqui is an Amazonian fish of great economic and environmental importance to Brazil and other South American countries. Several semen cryopreservation methodologies have been tested for different Brazilian fish species; however, there is little information on the use of this technique on tambaqui semen. The aim of the present study was to investigate the effect of osmolarity and activation solutions on sperm kinetics and, glucose solutions, cryoprotectants, dilution ratios, egg yolk and freezing methods on tambaqui semen freezing. The osmolarity of 230 mOsm was suitable for simultaneously yielding higher sperm motility (85%) and motility time (54 sec.) and osmolarities above 360 mOsm maintain immobile tambaqui sperm. The tambaqui semen can be successfully cryopreserved when diluted 1:9 in freezing medium composed of 5 percent glucose solution (290 mOsm) with 10 percent methylglycol and 5 percent egg yolk, and frozen directly in a dry shipper container.