Sperm cryopreservation of tiete tetra Brycon insignis (Characiformes): effects of cryoprotectants,extenders, thawing temperatures and activating agents on motility features

The aim of this study was to test the effects of cryoprotectants [dimethyl sulphoxide (DMSO) and methylglycol], extenders (0.9% NaCl, 5% glucose, Beltsville Thawing Solution^? and Merck III^?), thawing temperatures (30 and 60 °C) and activating agents (0.29% NaCl and 1% NaHCO₃) on the cryopreservation process of tiete tetra Brycon insignis sperm. Sperm was loaded in 0.5 mL straws, frozen in nitrogen vapour at ?170 °C and stored in liquid nitrogen. Post‐thaw sperm quality was evaluated in terms of subjective motility rate, quality motility score (0=no movement; 5=rapidly swimming spermatozoa), duration of motility and vitality (eosin–nigrosin staining). Post‐thaw sperm motility rate was greater in methylglycol (76–88%), compared with DMSO (23–59%). In general, the highest quality motility scores were observed when sperm was thawed at 30 °C and triggered in 1% NaHCO₃ (3.5–4.3). Duration of motility was longer when triggered in 1% NaHCO₃ (95–120 s) compared with 0.29% NaCl (69–107 s). Sperm vitality was not affected by any of the parameters tested and varied from 51% to 69% intact sperm. Brycon insignis sperm frozen in methylglycol combined with any of the extenders tested and using the methods described above yields motility above 57% and that should last long enough to fertilize oocytes.     

Life cycle inference and phylogeny of Ortholinea labracis n. sp. (Myxosporea: Ortholineidae), a parasite of the European seabass Dicentrarchus labrax (Teleostei: Moronidae), in a Portuguese fish farm

Ortholinea labracis n. sp. is described and its life cycle is inferred from a Southern Portuguese fish farm, with basis on microscopic and molecular procedures. This myxosporean parasite infects the urinary bladder of the European seabass Dicentrarchus labrax and the intestinal epithelium of a marine oligochaete of the genus Tectidrilus. Myxospores subspherical in valvular view and ellipsoidal in sutural view measuring 7.6 ± 0.3 (6.8–8.7) μm in length, 7.2 ± 0.2 (6.7–7.7) μm in width and 6.5 ± 0.4 (5.8–7.7) μm in thickness. Two polar capsules, 3.0 ± 0.2 (2.6–3.4) μm long and 2.4 ± 0.1 (2.0–2.9) μm wide, located at the same level, but with divergent orientation and opening to opposite sides of the suture line. Sequencing of the SSU rRNA gene revealed a similarity of 100% between the analysed myxospores and triactinomyxon actinospores. The phylogenetic setting of O. labracis n. sp. shows subgrouping in correlation with tissue tropism, but identifies this parasite as another exception to the main division of Myxosporea into the main freshwater and marine lineages.     

Chemical composition of Lippia spp. essential oil and antimicrobial activity against Aeromonas hydrophila

Phytotherapy can replace antibiotic administration as an alternative to control Aeromonas hydrophila, one of the main bacteria involved in the aetiology of farmed fish diseases. Given that plants of the Lippia spp. genus show biological potential for antimicrobial activity, this study evaluated the chemical composition of essential oils extracted from Lippia alba, Lippia origanoides and Lippia sidoides and their activity against A. hydrophila. The oils were obtained by steam distillation in a Clevenger‐type apparatus and their composition determined by gas chromatography and mass spectrometry (CG/MS). Antibacterial activity was assessed by calculating the minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) using broth microdilution method. The main compounds identified were geranial (25.4%) and neral (16.6%) in L. alba oil, carvacrol (40.4%) and p‐cymene (11.4%) in L. origanoides oil and thymol (76.6%) and ortho‐cymene (6.3%) in L. sidoides oil. The three Lippia species showed bacteriostatic and bactericidal action against A. hydrophila, with MICs and MBCs ranging from 1250 to 5000 μg mL^?1. Of the species tested, the best performance was obtained with essential oil of L. sidoides.     

Pre‐Columbian fisheries catch reconstruction for a subtropical estuary in South America

Small‐scale fisheries provide food and livelihoods for thousands of people along the Brazilian coastline. However, considerable uncertainties still surround the extent to which artisanal and subsistence fisheries contribute to the total of national landings and their historical ecological significance. Fisheries monitoring is deficient in Brazil, and historical records are limited to irregular accounts spanning the last few decades, while this coastline has supported human populations for at least 6,000 years. Here, we estimate pre‐Columbian subsistence catches for a large subtropical estuary in southern Brazil. Our results suggest that prehistoric populations may have extracted volumes of fish biomass higher than or comparable with historical subsistence fisheries in the region, and that the latter is likely underestimated. If a long‐term perspective is required to evaluate the current economic value and status of fisheries in subtropical and tropical South America, this should go beyond the historical time interval and integrate the contribution of pre‐Columbian archaeology.     

Involvement of cholinergic and adenosinergic systems on the branchial immune response of experimentally infected silver catfish with Streptococcus agalactiae

It has been recognized that the cholinergic and adenosinergic systems have an essential role in immune and inflammatory responses during bacterial fish pathogens, such as the enzymes acetylcholinesterase (AChE) and adenosine deaminase (ADA), which are responsible for catalysis of the anti‐inflammatory molecules acetylcholine (ACh) and adenosine (Ado) respectively. Thus, the aim of this study was to investigate the involvement of the cholinergic and adenosinergic systems on the immune response and inflammatory process in gills of experimentally infected Rhamdia quelen with Streptococcus agalactiae. Acetylcholinesterase activity decreased, while ACh levels increased in gills of infected animals compared to uninfected animals. On the other hand, a significant increase in ADA activity with a concomitant decrease in Ado levels was observed in infected animals compared to uninfected animals. Based on this evidence, we concluded that infection by S. agalactiae in silver catfish alters the cholinergic and adenosinergic systems, suggesting the involvement of AChE and ADA activities on immune and inflammatory responses, regulating the ACh and Ado levels. In summary, the downregulation of AChE activity exerts an anti‐inflammatory profile in an attempt to reduce or prevent the tissue damage, while the upregulation of ADA activity exerts a pro‐inflammatory profile, contributing to disease pathophysiology.     

Effect of live food transition time on survival,growth and metamorphosis of yellowtail clownfish, <Emphasis Type="Italic">Amphiprion clarkii</Emphasis>, larvae

Amphiprion clarkii, a popular marine ornamental fish, despite having an already established reproduction technology, still presents divergences regarding the feeding protocol used for its larviculture in what concerns the ideal day of transition from rotifers to Artemia. This study aimed to determine the optimum time to start supplying Artemia to larvae. Survival, growth, weight gain and metamorphosis of treatments: (T2) start of Artemia supply at the 2nd day after hatching (DAH); (T4) start at the 4th DAH; and (T6) start at the 6th DAH were evaluated. Survival rates ranged from 60 to 66 %. Fish in T2 had a number of metamorphosed fish statistically higher than T6 and began to metamorphose 1 day sooner than other treatments. The positive results obtained for T2 can be related to the premature ability of this species to capture large live food, which can provide many benefits to the larvae. It is concluded that it is possible to offer Artemia nauplii to yellowtail clownfish at 2 DAH.     

Natural Enemies of the Frankliniella Complex Species (Thysanoptera: Thripidae) in Ataulfo Mango Agroecosystems

A field survey was conducted in Ataulfo mango (Mangifera indica L.) orchards in Chiapas, Mexico, with the objective of determining the natural enemies of the Frankliniella complex species (Thysanoptera: Thripidae). Seven species of this genus feed and reproduce in large numbers during the mango flowering. Two representative orchards were selected: the orchard “Tres A” characterized by an intensive use of agrochemicals directed against thrips, and the orchard “La Escondida” that did not spray insecticides. During mango flowering, five inflorescences were randomly collected every 5 d in both orchards, for a total of 18 sampling dates. Results revealed the presence of 18 species of arthropods that were found predating on Frankliniella. There were 11 species in the families Aeolothripidae, Phlaeothripidae, Formicidae, Anthocoridae and Chrysopidae; and seven species of spiders in the families Araneidae, Tetragnathidae, and Uloboridae. Over 88% of predators were anthocorids, including, Paratriphleps sp. (Champion), Orius insidiosus (Say), Orius tristicolor (White), and O. perpunctatus (Reuter). The orchard that did not spray insecticides had a significantly higher number of predators suggesting a negative effect of the insecticides on the abundance of these organisms.     

Estimating nocturnal ecosystem respiration from the vertical turbulent flux and change in storage of CO2

Micrometeorological measurements of nighttime ecosystem respiration can be systematically biased when stable atmospheric conditions lead to drainage flows associated with decoupling of air flow above and within plant canopies. The associated horizontal and vertical advective fluxes cannot be measured using instrumentation on the single towers typically used at micrometeorological sites. A common approach to minimize bias is to use a threshold in friction velocity, u_*, to exclude periods when advection is assumed to be important, but this is problematic in situations when in-canopy flows are decoupled from the flow above. Using data from 25 flux stations in a wide variety of forest ecosystems globally, we examine the generality of a novel approach to estimating nocturnal respiration developed by van Gorsel et al. (van Gorsel, E., Leuning, R., Cleugh, H.A., Keith, H., Suni, T., 2007. Nocturnal carbon efflux: reconciliation of eddy covariance and chamber measurements using an alternative to the u_*-threshold filtering technique. Tellus 59B, 397–403, Tellus, 59B, 307-403). The approach is based on the assumption that advection is small relative to the vertical turbulent flux (F_C) and change in storage (F_S) of CO₂ in the few hours after sundown. The sum of F_C and F_S reach a maximum during this period which is used to derive a temperature response function for ecosystem respiration. Measured hourly soil temperatures are then used with this function to estimate respiration R_Rmax. The new approach yielded excellent agreement with (1) independent measurements using respiration chambers, (2) with estimates using ecosystem light-response curves of F_c + F_s extrapolated to zero light, R_LRC, and (3) with a detailed process-based forest ecosystem model, R_cast. At most sites respiration rates estimated using the u_*-filter, R_ust, were smaller than R_Rmax and R_LRC. Agreement of our approach with independent measurements indicates that R_Rmax provides an excellent estimate of nighttime ecosystem respiration.     

Direct Detection of Mycobacterium bovis in Bovine Lymph Nodes by PCR

Thirty‐five lymph node samples were taken from animals with macroscopic lesions consistent with Mycobacterium bovis infection. The animals were identified by postmortem examination in an abattoir in the northwestern region of state of Paraná, Brazil. Twenty‐two of the animals had previously been found to be tuberculin skin test positive. Tissue samples were decontaminated by Petroff’s method and processed for acid‐fast bacilli staining, culture in Stonebrink and Lowenstein‐Jensen media and DNA extraction. Lymph node DNA samples were amplified by PCR in the absence and presence (inhibitor controls) of DNA extracted from M. bovis culture. Mycobacterium bovis was identified in 14 (42.4%) lymph node samples by both PCR and by culture. The frequency of PCR‐positive results (54.5%) was similar to that of culture‐positive results (51.5%, P > 0.05). The percentage of PCR‐positive lymph nodes increased from 39.4% (13/33) to 54.5% (18/33) when samples that were initially PCR‐negative were reanalysed using 2.5 μl DNA (two samples) and 1 : 2 diluted DNA (three samples). PCR sensitivity was affected by inhibitors and by the amount of DNA in the clinical samples. Our results indicate that direct detection of M. bovis in lymph nodes by PCR may be a fast and useful tool for bovine tuberculosis epidemic management in the region.     

Frequency of BCoV detection by a semi-nested PCR assay in faeces of calves from Brazilian cattle herds

Bovine coronavirus (BCoV) is one of the main causes of neonatal calf diarrhoea. Several diagnostic assays have been employed to detect the presence of the virus in stool samples from calves. Despite this, the frequency of BCoV infection among Brazilian and even South American cattle herds has yet to be well characterised. This study describes the occurrence of BCoV infection among calves from dairy and beef herds in four Brazilian states. A total of 282 stool samples from 1 to 60-day-old calves were evaluated for the presence of BCoV by a semi-nested (SN) PCR assay. The animals were from herds (n = 23) located in three geographical regions in Brazil (south, southeast, and center-west). The specific BCoV amplicon was detected in 15.6% (44/282) of the faecal specimens examined, of which 95.4% (42/44) were from diarrhoeic and 4.6% (2/44) from asymptomatic calves. The specificity of the SN-PCR amplicons was evaluated by restriction fragment length polymorphism (RFLP) analysis. The results show that the BCoV is widespread, mainly among calves from 16 to 30-days-old (p = 0.0023), and verify the association between BCoV infection and clinical signs of diarrhoea (p = 0.005). These findings emphasise the importance of this virus in enteric infections of Brazilian cattle herds.