Increasing storage capability of pacu (Piaractus mesopotamicus) embryos by chilling: development of a useful methodology for hatcheries management.

Cryopreservation of fish gametes has been studied extensively in the last few decades, but the successful cryopreservation of fish embryos remains elusive. However, recent studies using short-term chilling techniques have shown that it is possible to store embryos at low temperatures with no significant loss in viability. Information on cryopreservation of Neotropical freshwater fish embryos has so far been very limited in the literature. In the present study, chilling protocols for storage of pacu embryos at -8°C for up to 24 h were studied using different concentrations of sucrose in methanol. Embryos tolerated the subzero temperature for up to 6 h with no adverse effects (P > 0.05). After 12 h chilling, hatching rate of 64.0 +/- 3.5 percent was recorded. Low temperature storage of pacu embryos by chilling is detailed here for the first time. Further studies are needed to extend the storage time and to improve the hatching rate.

Morphological characteristics of ovarian development of two Nile tilapia (Oreochromis niloticus) strains in mixed-culture systems / Características morfológicas do desenvolvimento ovariano de duas linhagens de tilápia-do-nilo (Oreochromis niloticus), em sistemas de cultivo misto

This study was carried out to morphologically characterize and classify the stages of gonad development in different Nile tilapia strains (Oreochromis niloticus). Eighty-four and ninety-two ovaries from Bouaké and Chitralada strains, respectively, were evaluated at different ovarian developmental phases: initial (104 days of culture), intermediate (152 days of culture), and the final (279 days of culture). The ovaries were microscopically evaluated and submitted to histological processing and hematoxylin-eosin staining to determine their characteristics and be classified. No morphological differences in ovaries between strains were observed during the initial phase (stage A - immature). During the intermediate growing phase, higher gonad development was observed for Chitralada strain (stage B - maturation) in comparison with Bouaké strain (stage A - immature). During the final growing phase, no differences between strains were observed for morphological characteristics (stage C - mature). Despite the similarities in reproductive behavior of the Bouaké and Chitralada females at the end of the final growing phase (gain weight phase), differences for macroscopic and microscopic aspects and oocytes during the initial and intermediate growing phases of the strains were observed.

Este trabalho teve como objetivo caracterizar morfologicamente e classificar os estádios de desenvolvimento gonadal de tilápias do Nilo (Oreochromis niloticus) de linhagens distintas. Foram avaliados 84 ovários da linhagem Bouaké e 92 da linhagem Chitralada, em diferentes fases de desenvolvimento: inicial (imatura - 104 dias de cultivo), intermediária (crescimento - 152 dias de cultivo) e final (ganho de peso - 279 dias de cultivo). Os ovários foram analisados macroscopicamente e submetidos a procedimento histológico, corados com hematoxilina-eosina, para determinação das características microscópicas e subsequente classificação. Não foram observadas diferenças morfológicas nos ovários entre as linhagens na fase inicial (estádio A - imaturo). Na fase intermediária, os ovários revelaram diferenças morfológicas, evidenciando maior desenvolvimento gonadal para a linhagem Chitralada, (estádio B - maturação) em relação à Bouaké (estádio A). Na fase final (ganho de peso) os ovários não apresentaram diferenças morfológicas entre as linhagens (estádio C - maduro). Apesar de semelhanças no comportamento reprodutivo das fêmeas das linhagens Bouaké e Chitralada, na fase final (ganho de peso), diferenças, em relação à classificação da fase intermediária nos aspectos macroscópicos e microscópicos e diâmetro dos ovócitos, foram observadas.

[The repercussions of pulmonary congestion on ventilatory volumes, capacities and flows]. / Repercussões da estase pulmonar sobre volumes, capacidades e débitos ventilatórios.

OBJECTIVES: To evaluate the effects of pulmonary congestion on pulmonary function. STUDY DESIGN: Prospective study performed in patients with left ventricular failure or mitral stenosis. MATERIAL AND METHODS: Forty-eight hospitalized patients were included suffering from pulmonary congestion either from left ventricular failure or mitral stenosis. While in hospital all patients were submitted to right heart catheterization by the Swan-Ganz method and also to an echocardiographic examination. Within 48 hours after the patients were submitted to the following lung function studies: lung volumes and capacities by the multi-breath helium dilution method and airway flows by pneumotachography. Respiratory symptoms were evaluated by the Medical Research Council Questionnaire and the functional class classified according to the NYHA. Correlations were made between the functional and clinical data. RESULTS: Regarding the cardiac evaluation patients presented with a mean pulmonary wedge pressure of 19.9 +/- 8.6 mmHg, a cardiac index of 2.5 +/- 0.8 l/min/m2, an end diastolic dimension of the left ventricle of 65.9 +/- 10.1 mm, and end systolic dimension of 51.2 +/- 12.2 mm, with a shortening fraction of 21.8 +/- 9.5%. The pulmonary evaluation showed a restrictive syndrome with a reduction in the mean values of the following parameters: total pulmonary capacity 71 +/- 14.4% of the predicted value (pv), forced vital capacity (FVC) 69.8 +/- 20.5% pv, and forced expiratory volume (FEV1) of 64 +/- 21.8% vp. The index FEV1/FVC was within the normal value of 72.7 +/- 9.7%. These lung function results did not correlate significantly with either the clinical, the hemodynamic or echocardiographic findings. CONCLUSION: In these group of patients pulmonary congestion led to the development of a restrictive syndrome which failed to correlate in severity with the duration of the disease, the pulmonary wedge pressure and the left ventricular function.