Biological filtration properties of selected herbs in an aquaponic system

This study was conducted to determine the biological filtration capabilities of some culinary herbs co‐cultured with lemon fin barb hybrid in a nutrient film technique (NFT) recirculating aquaponic system. Lemon fin barb hybrid (Hypsibarbus wetmorei ♂ × Barbonymus gonionotus ♀) fingerlings were stocked in twelve 2‐tonne fibreglass tanks at 25 fish per tank and co‐cultured with Chinese celery (Apium graveolens var. secalinum Alef.), coriander (Coriandrum sativum) and peppermint (Mentha × piperita) for seven weeks. The impacts of the waste generated by the fish on the water quality, the filtration capability of the herbs and the ability of fish and herbs to retain nutrients (NPK) were also estimated. All the herbs showed water purifying potentials to varying degrees as significantly lower levels of nitrogenous compounds (NH₃‐N, NO₃‐N, NO₂‐N) were observed after the herbal filtration. The plant growth seemed to be affected by their ability to absorb nutrients and consequently purify the culture medium. Interestingly, the lemon fin barb hybrid also showed significant differences in terms of weight gain, but the nutrient retention among fish treatments was not statistically different. The plants absorbed less phosphorus and potassium than the fish. After computing for the total system percentage of NPK recovered, nitrogen was the most retained nutrient. The peppermint showed superiority in terms of gross biomass and water purifying potential compared to the Chinese celery and coriander.     

Transmission of Mycobacterium chelonae and Mycobacterium marinum in laboratory zebrafish through live feeds

The zebrafish (Danio rerio) is a popular vertebrate model organism used in a wide range of research fields. Mycobacteriosis, caused by Mycobacterium species, is particularly concerning because it is a common disease associated with chronic infections in these fish. Infections are also a source of uncontrolled experimental variance that may influence research results. Live feeds for zebrafish are common and include paramecia (Paramecium caudatum), brine shrimp (Artemia franciscana) and rotifers (Branchionus spp.). Although nutritionally beneficial, live feeds may pose a biosecurity risk. In this study, we investigate transmission of Mycobacterium chelonae and Mycobacterium marinum through these three live feeds. We show that all three live feeds ingest both M. marinum and M. chelonae and can transmit mycobacterial infections to zebrafish. This observation emphasizes the need for live feeds to be included in the consideration of potential biosecurity risks. This study is of importance to other beyond the zebrafish community, including those of additional aquatic models and those using live feeds for other types of aquaculture.     

Length‐based assessment of larval lamprey population structure at differing spatial scales

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Comparison of traditional and environmental DNA survey methods for detecting rare and abundant freshwater fish

1. Detecting rare species is often a necessity for conservation and management, yet challenging for many field survey methods. Environmental DNA (eDNA) is a highly promising solution that has been shown to outperform many established survey methods.
2. Macquarie perch (Macquaria australasica) is an endangered native species that has declined significantly in range and abundance. Detection of M. australasica was compared with an abundant alien fish species (Oncorhynchus mykiss) using eDNA and three conventional survey methods: gill nets, electrofishing and fyke nets.
3. eDNA occupancy estimates for both fish species were compared using four different models to investigate what effect these differences have on false positives and false negatives for the rare and common fish species. These models used unadjusted eDNA detections in water samples, eDNA detections that have been screened using a limit of detection method to remove potential false positives, eDNA data supplemented with a second survey method, or eDNA data augmented with sequencing of positive polymerase chain reaction replicates.
4. eDNA surveying as a single detection method was found to be more efficient and sensitive compared with each capture method separately and combined. Occupancy estimates for the common and rare species did not vary significantly between the four site occupancy-detection models, suggesting that supplementary data may not have as much effect on occupancy estimates compared with other approaches such as temporal or spatial sampling.
5. We conclude that eDNA outperforms the three established survey methods for both a rare and common freshwater fish species. Although there was no significant effect of augmenting eDNA survey methods with other survey data, additional data may improve confidence in detection, and provide confirmatory evidence for unexpected or new detections of a species.

     

Averting the baiji syndrome: conserving habitat for critically endangered dolphins in Eastern Taiwan Strait

• 1. Numbering no more than 100 individuals and facing many threats, the geographically isolated Eastern Taiwan Strait population of Indo‐Pacific humpback dolphins (Sousa chinensis) is in peril. The estuarine and coastal waters of central‐western Taiwan have historically provided prime habitat for these dolphins, but environmental conditions today bear little resemblance to what they were in the past.
• 2. The humpback dolphins must share their habitat with thousands of fishing vessels and numerous factories built upon thousands of hectares of reclaimed land.
• 3. They are exposed to chemicals and sewage released from adjacent terrestrial activities. Noise and disturbance associated with construction, vessel traffic and military activities are features of everyday life for these animals.
• 4. Measures to slow the pace of habitat deterioration and reduce the many risks to the dolphins are urgently needed. As one practical step in this direction, this paper describes the habitat needs of these small cetaceans so that decision makers will be better equipped to define ‘priority habitat’ and implement much needed protection measures under the terms of local legislation.
• 5. The preferred habitat of these dolphins in Taiwan consists of shallow (<30 m), near‐shore marine waters with regular freshwater inputs.
• 6. For such a small, isolated and threatened population, ‘priority habitat’ should not be limited to areas of particularly intensive dolphin use or high dolphin density, but rather it should encompass the entire area where the animals have been observed (their current ‘habitat’), as well as additional coastal areas with similar bio‐physical features (‘suitable habitat’). Such a precautionary approach is warranted because the loss of only a few individuals could have serious population‐level consequences.
• 7. While conventional socio‐economic analysis might suggest that implementing protection measures over an area stretching ～350 km north–south along Taiwan's west coast and ～3 km out to sea would be too ‘costly’, the loss of this charismatic species from Taiwan's waters would send a troubling message regarding our collective ability to reconcile human activities with environmental sustainability. Copyright © 2010 John Wiley & Sons, Ltd.

     

Bioaccumulation of cadmium and its biochemical effect on selected tissues of the catfish (<Emphasis Type="Italic">Clarias gariepinus</Emphasis>)

The present study examines the pattern of accumulation of cadmium (Cd) and its biochemical effects on selected tissues of a variety of African catfish (Clarias gariepinus), after exposure to various doses of Cd. The results obtained indicate that at the end of 21 days of exposure, the total tissue organ cadmium concentration followed the pattern kidney > gill > liver > muscle for each of the exposure concentrations. The levels of Cd in these organs were higher than those in ambient water. Moreover, while the rate of uptake of Cd increased with time in the kidney, liver and muscle, it decreased in the gill. Superoxide dismutase (SOD) was significantly elevated only in the kidney of catfish treated with 0.2 and 0.4 ppm of Cd for 7 days compared with the control. Conversely, gill SOD was significantly decreased in the same concentrations of Cd-treated catfish relative to the control. Statistically similar levels of SOD were observed in the liver, brain and muscle with all the treatments after the same duration of treatment. In the fish exposed for 21 days, SOD activity was significantly decreased in the kidney with a corresponding increase in lipid peroxidation (LPO), but it manifested only with the 0.2- and 0.4-ppm Cd treatment relative to the control. In the liver, however, Cd exposure significantly increased SOD in the 0.2- and 0.4-ppm treatments of the same duration. In conclusion, the present study indicates that the accumulation of Cd and its effect on SOD and LPO in C. gariepinus is dependent on concentration, tissue and time     

Prospective trial of autologous conditioned plasma versus hyaluronan plus corticosteroid for elbow osteoarthritis in dogs

This prospective, randomized, double-blinded trial compared outcomes in dogs with bilateral elbow osteoarthritis (OA) treated with hyaluronan plus methylprednisolone (HA + S) or autologous conditioned plasma (ACP^®; Arthrex). An investigator blinded to the treatments graded lameness (0–4) before and 6 months after a single injection with either HA + S or ACP. Clients were blinded to treatment and completed a validated survey before and 1, 6, 12, and 24 weeks after injection. Ten dogs (5 per group) completed all parts of the study. Pre-treatment lameness grades were 1.2 ± 0.97 for HA + S and 1.8 ± 1.1 for ACP and were not different between groups. Post-treatment lameness grades were 0.4 ± 0.55 for HA + S and 0.8 ± 0.64 for ACP with significant (P < 0.05) improvement with either treatment but without differences between groups. Client-based assessments demonstrated improvements in activity, lameness, and pain with HA + S and ACP. These data suggest that both treatments have beneficial effects for dogs with bilateral elbow OA.     

The role of p38 mitogen-activated kinase (MAPK) in the mechanism regulating cyclooxygenase gene expression in equine leukocytes

The goal of this study was to define the role for p38 mitogen-activated kinase (MAPK) in the signaling mechanism regulating pro-inflammatory cyclooxygenase (COX) gene expression in lipopolysaccharide (LPS)-activated equine leukocytes for the purposes of identifying novel targets for anti-inflammatory therapy in endotoxemic horses. The p38 MAPK has been shown to positively regulate inflammatory gene expression in human leukocytes and can be activated by a variety of stimuli including LPS, TNF-alpha, and IL-1. Activation-associated phosphorylated p38 MAPK has been implicated in the up-regulation of several inflammatory genes, including COX-2 which ultimately results in the production of prostanoids that are responsible for the pathophysiology associated with endotoxemia. Our hypothesis is that activation of p38 MAPK is essential for LPS-induced COX-2 expression in equine peripheral blood leukocytes. We tested our hypothesis by investigating the effects of the specific p38 MAPK inhibitors SB203580 and SB202190 on LPS-induced COX-2 protein expression and PGE(2) production in equine leukocytes. LPS stimulation activated p38 MAPK and increased COX-2 expression in a dose-dependent manner with maximal activation observed after 30min and 4h, respectively, at a concentration of 10 ng/ml LPS. In contrast, LPS stimulation did not affect COX-1 protein expression. Pretreatment with SB203580 or SB202190 significantly inhibited LPS-induced activation-associated p38 MAPK phosphorylation, COX-2 mRNA and protein levels, and PGE(2) production in equine leukocytes. Maximal inhibition of LPS-induced COX-2 protein expression was achieved at a concentration of 10 microM SB203580. We concluded that p38 MAPK is essential for LPS-induced COX-2 expression suggesting that p38 MAPK is a potential target for anti-inflammatory therapy during equine endotoxemia.     

The effect of sample storage on the extraction of Cu,Zn, Fe,Mn and organic material from oxidized estuarine sediments

Concentrations of extractable Cu, Zn, Fe and Mn in oxidized estuarine sediment are influenced by the manner and time of storage between collection and extraction. No storage method tested completely preserves the initial chemical and physical characteristics of the sediment. Freezing or (for some extractions) drying are adequate methods of storage if sediments are to be extracted only with acids. However, if a variety of extractants is to be used, extractions should be conducted as soon as practical after collection.