Journal of aquatic animal health最新文献

Species-specific hematological reference values are essential for diagnosis and treatment of disease and maintaining overall health of animals. This information is lacking for many species of elasmobranchs maintained in zoos and aquaria, thus reducing the effectiveness of care for these animals. Descriptive statistics and reference intervals were calculated for hematocrit and complete blood cell counts, biochemistry and protein electrophoresis parameters, trace minerals, vitamins, heavy metals, reproductive hormones, and fatty acids in the blood of 153 wild Sand Tigers Carcharias taurus of both sexes and a range of sizes caught in Delaware Bay (Delaware, USA). Mean hematocrit, total white blood cell counts, lymphocyte differentials, glucose, phosphorus, amylase, and aspartate aminotransferase levels were significantly higher in juveniles than in adults. Levels of estradiol, progesterone, testosterone, and differences in selenium and eicosapentaenoic acid (a polyunsaturated fatty acid) between males and females suggest that they are important parameters for improving Sand Tiger breeding success in managed care. Finally, blood metal levels for arsenic, cadmium, lead, and mercury suggest low levels of contaminant exposure for Sand Tigers during their summer residence in Delaware Bay. The results of this study provide baseline health parameters for wild Sand Tigers that will aid in effective maintenance of aquarium animals and contribute to a greater understanding of the biology of these sharks and efforts to accomplish sustainable management of their populations.

The increased sensitivity of advanced molecular techniques greatly exceeds the sensitivities of traditional detection methods for infectious agents. This sensitivity causes difficulty in interpreting the biological significance of such detections in fish (and shellfish), especially when the agent(s) cannot be cultured in the laboratory. In the Pacific Northwest, including Canada and Alaska, molecular detections of “new” (unknown or known but discovered in a different geographic location or fish host) potentially infectious agents in fish have received extensive media attention and misinterpretation that call for resource agencies to change current fish health surveillance practices or policies to include these agents. Fish health specialists from several of these agencies and organizations (see Acknowledgments) advise that any policy changes should be made only after further investigations to avoid wasting resources to conduct surveillance for organisms that are not significant to fish health or for noninfectious genetic material that does not represent a viable agent. Molecular detection is not proof of agent viability within or on host tissues and requires further investigation regarding the agent's ability to replicate and evidence that the agent causes substantial risk of disease to exposed fish populations. This document provides examples of molecularly detected agents causing public concern that were accompanied by little or no data to provide context and assessment of biological significance, highlights important questions to be answered regarding these detections, and provides a suggested pathway of investigative criteria to determine viability and pathogenicity of such agents that are necessary for consideration of any changes to aquatic animal health practices and policies.

The growth and development of healthy culture subjects are essential in increasing productivity in the aquaculture industry. A primary determinant of aquatic animal productivity is the ambient microbial population. If an aquatic animal's microbiome is diverse, with bacteria favoring beneficial over pathogenic species, the health and growth of the animal (i.e., fish or crustacean) can be substantially improved. Embryonic and newly hatched Zebrafish Danio rerio larvae were reared in the presence of (1) water from the broodstock culture tank as a control, (2) a probiotic solution containing 19 strains of live lactic acid bacteria (LAB), or (3) an antibiotic (AB) solution with amoxycillin. Developmental parameters were monitored until 10 d postfertilization. Bacteria present in the water and larvae were cultured and identified by sequencing the V4 hypervariable region of bacterial 16S ribosomal RNA. Probiotic-treated larvae showed significant increases in every measured morphological parameter and in survival compared to the controls and AB-treated larvae, including TL, eye development, and swim bladder development before first feeding. Staining with DASPEI (2-(4-[dimethylamino]styryl)-N-ethylpyridinium iodide) produced fluorescence, revealing increased mitochondrial activity in the gastrointestinal tracts of probiotic-treated larvae and reflecting advancement of initial metabolic function. Probiotic-treated larvae showed accelerated yolk absorption, resulting in increased nutrient mobilization and growth. Microbial analyses revealed a greater concentration of bacteria in larvae in response to the probiotic treatment compared to the other two treatments. Species identified in all three treatments included Pseudomonas spp. and Aeromonas spp. (Proteobacteria). The second most diverse and abundant microbiome was seen in controls, whereas AB-treated larvae had the least diverse microbiome. All treatments revealed the presence of proteobacteria, but an AB-resistant pathogenic bacterium (Stenotrophomonas maltophilia) was identified in the AB group. These results reveal that the presence of LAB and other bacteria favorably influenced early larval growth, development, digestive function, and survival in Zebrafish even before the onset of feeding.

Vibrio parahaemolyticus is an important pathogen causing pandemic diseases in marine animals and brings about severe economic losses in aquaculture worldwide. The emergence of multi-drug-resistant V. parahaemolyticus and the prohibition of antibiotics both require the development of new therapeutic agents with alternative action. In this study, the effect of gallnut Galla chinensis water extract (GWE) on V. parahaemolyticus growth and virulence was investigated to determine the potential for its use in disease prevention and treatment in aquaculture. The minimum inhibitory concentration and minimum bactericidal concentration of GWE against V. parahaemolyticus were identified as 0.49 and 0.98 mg/mL, respectively. Membrane damage in V. parahaemolyticus was further verified through the increase of conductivity and leakage of nucleic acids and proteins. Moreover, GWE caused membrane invaginations and damage in V. parahaemolyticus as observed via scanning electron microscopy. After treatment with GWE, the biofilm formation and the activities of respiratory chain dehydrogenase, lactate dehydrogenase, and succinate dehydrogenase of V. parahaemolyticus were all significantly inhibited. These findings suggest that GWE has the potential to be developed as a supplemental agent to mitigate the infections caused by V. parahaemolyticus in aquaculture.

The International Workshop for Ex-Situ Marine Teleost Nutrition and Health, hosted by Disney's Animals, Science and Environment in conjunction with the Comparative Nutrition Society, brought together over 50 animal experts and scientists representing 20 institutions to review current science and identify challenges of marine teleost nutrition and health. Invited speakers presented critical information and current research topics for areas of emphasis and expertise. Subject matter experts identified knowledge gaps and primary areas of focus to guide the scientific community's research efforts to improve the care of ex situ marine teleosts. The clinical medicine working group highlighted standardized approaches to ante- and postmortem sample collection, diet biosecurity and supplementation, advanced diagnostic methods, and expanded training in fish nutrition. Nutrition identified the creation of a husbandry and feeding management manual, comprehensive feeding program review and design, and specialty feeder/life stage nutrition as areas of focus, while animal husbandry focused on body condition scoring, feed delivery techniques, and behavioral husbandry topics. The physiology and chemistry and water quality working groups discussed components of the aquatic environment and their effects on fish health, including organic matter constituents, microbial diversity, disinfection, and managing microbiota. Finally, we reviewed how epidemiological approaches and considerations can improve our evaluation of aquarium teleost nutrition and health. The goals outlined by each working group and supporting literature discussion are detailed in this communication and represent our goals for the next 3 to 5 years, with the ultimate objective of the workshop being the production of a husbandry manual for marine teleost nutrition and health. Any scientists who feel that their experience, research, or interests align with these goals are invited to participate by contacting the authors.

To evaluate the effects of nitrite on the oxidative damage of blood cells of Grass Carp Ctenopharyngodon idella, the isolated hemocytes were exposed to nitrite (0, 1, 10, or 100 mg/L) for up to 24 h. Hemoglobin (Hb) and methemoglobin (MetHb) concentrations, reactive oxygen species (ROS) and malondialdehyde (MDA) levels, mitochondrial membrane potential (∆Ψm), and antioxidant enzyme activity were assayed to assess hematological parameters and the antioxidant defense mechanism. Results showed a remarkable decrease in Hb concentration with increasing nitrite concentration after a 24-h exposure, while the MetHb concentration increased significantly in nitrite exposure groups. The levels of ROS, ∆Ψm, and MDA increased to varying degrees with increases in nitrite exposure concentration and time. The total antioxidant capacity, catalase (CAT) activity, glutathione peroxidase (GPx) activity, and glutathione content showed a trend of rising initially and then decreasing with prolonged exposure time. Superoxide dismutase (SOD) activity was higher in the 1-mg/L nitrite exposure group and lower in the 100-mg/L group than in the control. The relative messenger RNA expression ratios of cat, sod1, and gpx were up-regulated significantly in the 1- and 10-mg/L groups and then declined in the 100-mg/L group. Therefore, it can be concluded that nitrite exposure activates the antioxidant defense mechanism of Grass Carp hemocytes and that the balance of oxidant–antioxidant homeostasis will be undermined by higher nitrite doses or longer exposure periods.

White Sturgeon Acipenser transmontanus are cultured for human consumption as well as for conservation purposes. In this study, two commercially available portable devices for measuring glucose and lactate were compared to a benchtop analyzer and blood reference intervals were generated using heparin plasma collected from 43 healthy White Sturgeon yearlings. The generated normal ranges were used to compare plasma values collected from Veronaea botryosa-infected White Sturgeon at 10, 20, and 30 d postchallenge (dpc). In the 43 healthy yearlings, significantly different glucose and lactate values were obtained when comparing the portable devices to the benchtop analyzer. In the portable devices, blood glucose showed a consistent bias of 12.3 mg/dL and blood lactate showed a proportional bias. The detected blood glucose values in infected sturgeon were significantly different from those in noninfected controls when using the benchtop analyzer at 20 and 30 dpc and when using the portable device at 20 dpc. However, blood glucose in infected individuals and controls was within the reference interval on either device. No significant difference was noted for lactate measurements in infected sturgeon. The results of this study indicate that portable devices for blood glucose and blood lactate evaluation in White Sturgeon may be useful in a setting where relative values are an acceptable approximation of absolute values.

Acute morbidity and mortality of marlins (family Istiophoridae) in hook-and-line fisheries have been studied; however, there has been little or no investigation of the skeletal injuries incurred from terminal tackles that could lead to decreased rates of postrelease survival. The objective of this study was to evaluate skeletal injuries in recreationally angled Atlantic Blue Marlin Makaira nigricans from the 2019 Big Rock Blue Marlin Tournament in Morehead City, North Carolina. We examined heads of six Blue Marlin that were angled using artificial lures rigged with J-hooks and harvested for weigh-in. The head of each Blue Marlin was scanned using computed tomography (CT) and examined with gross dissection. The CT interpretation revealed that two Blue Marlin had minimally displaced fractures of the maxilla, one of which also had a fracture to the lachrymal bone. These radiographic lesions were associated with penetrating hook injuries. The CT images also revealed degenerative changes within the quadrate-articular joint in four Blue Marlin, which was associated with fish weight; the causes and consequences of these degenerative changes are unknown. Although the hooking-related jaw fractures likely result in acute pain, their impact on postrelease morbidity is unknown and the impact on postrelease mortality is suspected to be small.

Largemouth Bass virus (LMBV) first became a concern in Kansas when it was identified as a potential cause of decreased catch rates at Crawford State Fishing Lake in 2007. The discovery of LMBV in eight additional impoundments from 2008 to 2017 increased concern about the prevalence and effects of LMBV in Kansas. In response, the Kansas Department of Wildlife, Parks, and Tourism tested 25 Largemouth Bass Micropterus salmoides impoundments for the presence of LMBV. The objectives of this study were to quantify the incidence of LMBV and examine differences in population metrics (i.e., body condition, relative abundance, and growth). A total of 1,260 Largemouth Bass were collected by using standard spring electrofishing surveys, and sagittal otoliths were collected from all of the sampled fish to estimate growth rates. Of the 25 study impoundments, 14 tested positive for LMBV. There was no evidence of LMBV effects on body condition, relative abundance of quality-length fish, or growth rates. The initial dates of LMBV infection of Largemouth Bass in these impoundments are unknown. The LMBV-positive populations in Kansas may have been exposed to the virus many years ago, and the fish may be in the process of rebounding from any potential negative effects.

Regulatory costs on aquaculture farms have been shown to be of a magnitude that warrants additional analysis. The drivers of farm-level costs of fish health inspections were identified in this study from national survey data on U.S. salmonid farms. The greatest costs identified were related primarily to state fish health requirements for inspection and testing to certify that fish are free of specific pathogens prior to approval of necessary permits to sell and/or transport animals. Fish health inspection costs included laboratory testing, farm personnel time, veterinary fees, and shipping samples to laboratories, with laboratory testing and the value of farm personnel time being the most expensive components. Principal cost drivers were the number of tests and whether required sampling was farmwide or for each lot as identified by the collector. Farmers who primarily sold into recreational markets had greater fish health costs than farmers who primarily sold food fish because of the greater numbers of species and size-/age-classes of salmonids on their farms. Regulatory requirements to test all species and size-/age-classes on farms increased inspection costs by increasing the total number of tests, the total value of fish sacrificed, and shipping costs. Consequently, for farms with more than one species or more than one size-/age-class, annual farm-level testing was less costly than annual lot-based testing. Increased numbers of tests in a given year, although reported by only a few respondents, can increase costs dramatically and turn profitable farms unprofitable, even food fish farms. Smaller salmonid farms experienced disproportionately greater inspection cost burdens than did larger farms. The fish health inspection scenario of only one annual inspection of only the most susceptible species and size-/age-class showed a cost burden that did not generate economic distress, even on smaller salmonid farms. Other scenarios modeled (based on survey data) that included lot-based surveys of multiple species and size-/age-classes resulted in substantially greater fish health inspection costs that led to unprofitability for various farm sizes and business types. Study results suggest that implementing Comprehensive Aquaculture Health Program Standards might allow for risk- and pathogen-based reductions in the total number of inspections and fish sampled while maintaining equivalent or greater health status compared to current methods. American Fisheries Society–Fish Health Section Blue Book inspection methods are interpreted and applied inconsistently across states and generally yield lot- rather than farm-level health attestations because the history of testing results, risk assessment, and biosecurity practices are not typically taken into account. The cost effects of alternative fish health sampling and testing requirements should be considered in decisions and policy on fish health regulation.