Isolation of active compounds from methanol extracts of Toddalia asiatica against Ichthyophthirius multifiliis in goldfish (Carassius auratus)

The parasitic ciliate Ichthyophthirius multifiliis infests all species of freshwater fish and can cause severe economic losses in fish breeding. The present study aims to evaluate the antiparasitic activity of the active components from Toddalia asiatica against I. multifiliis. Bioassay-guided fractionation and isolation of compounds with antiparasitic activity were performed on the methanol extract of T. asiatica yielding two bioactive compounds: chelerythrine and chloroxylonine identified by comparing spectral data (NMR and ESI-MS) with literature values. Results from in vitro antiparasitic assays revealed that chelerythrine and chloroxylonine could be 100% effective against I. multifiliis at the concentration of 1.2 mg L^?1 and 3.5 mg L^?1, with the median effective concentration (EC₅₀) values of 0.55 mg L^?1 and 1.90 mg L^?1 respectively. In vivo experiments demonstrated that fish treated with chelerythrine and chloroxylonine at the concentrations of 1.8 and 8.0 mg L^?1 carried significantly fewer parasites than the control (P < 0.05). The acute toxicity (LC₅₀) of chelerythrine for goldfish was 3.3 mg L^?1.     

Trichinella spiralis—A potential anti-tumor agent

Murine forestomach carcinoma (cell line MFC), ascitic hepatoma (cell line H22) and sarcoma (cell line S180) solid tumor models were used to test the anti-tumor effect of Trichinella spiralis in vivo. Mice previously infected by oral administration of 400 viable T. spiralis larvae per mouse for 7 days were grafted with various solid tumor cell lines. Other groups of tumor-bearing mice were given caudal vein injection of crude extracts of adult and newborn larvae at 17.5, 35.0 or 70.0 mg kg^?1. These treatments to inhibit tumor growth were dose-dependent (p < 0.05). The anti-proliferative activity of crude T. spiralis extract was examined in vitro at 0.035, 0.070 or 0.140 mg ml^?1 using MFC, H22, S180, human chronic myeloid leukemia cell line (K562) and hepatoma cell line (H7402), tumor cell proliferation in vitro was measured by methyl thiazolium stain and was inhibited in dose-dependent manner (p < 0.05). At the same doses, crude T. spiralis extracts induced apoptosis of K562 and H7402 as detected by DNA fragmentation. Cell cycle analysis indicated that crude T. spiralis extracts, at 0.140 mg ml^?1, arrested the cell cycle of K562 and H7402 in G1 or S phase. It is concluded that T. spiralis contains anti-tumor active agent.     

Investigation into the prevalence of coccidiosis and maduramycin drug resistance in chickens in China

Coccidiosis is a parasitic disease that affects the poultry industry worldwide, having major economic impacts on poultry by reducing performance and decreasing productivity. This disease not only hinders the growth of chickens but also facilitates other epidemic diseases. Coccidiosis is mainly controlled by prophylactic coccidiostats administrated in the feed. However, the extensive use of these drugs has resulted in the development of drug resistance by Eimeria spp., which causes coccidiosis. The aim of the survey was to acquire data on the prevalence of coccidiosis and drug resistance of field isolates in chickens in China. We examined 545 farms across nine different geographic provinces over a 5-year period. These included Beijing, Sichuan, Zhejiang, Shandong, Guangdong, Fujian, Liaoning Provinces, Inner Mongolia and Xinjiang Uygur Autonomous Regions. The results indicated that oocyst per gram faeces (OPG) and coccidiosis morbidity rate increased when non-prophylactic or low doses of coccidiostats were used. Coccidiosis morbidity rate in Guangdong Province was the highest, leading to greater, more frequent use of diverse types of coccidiostats. Consequently, the Guangdong Province had the most serious drug resistance problem. In contrast, coccidiosis morbidity rates in Inner Mongolia, Fujian and Liaoning were relatively low, leading to a reduced level of coccidiostats use, which resulted in less drug resistance. The threshold of a coccidiosis outbreak was an OPG level of >20 000. When the OPG levels were ≥50 000, chickens were in danger of clinical coccidiosis, and here coccidia generated a certain degree of resistance to the drug when administered. Coccidiostat resistance started to appear when the OPG level reached ca. 20 000 using 2 mg kg^?1/5 mg kg^?1, respectively, of maduramycin, whereas 5 mg kg^?1 of maduramycin developed severe drug resistance.     

Pharmacokinetics,plasma protein binding and bioavailability of moxifloxacin in Muscovy ducks after different routes of administration

In this study the disposition kinetics and plasma availability of moxifloxacin in Muscovy ducks after single intravenous (i.v.), intramuscular (i.m.) and oral (p.o.) administrations of 5 mg kg^?1 b.wt. were investigated. The concentrations of moxifloxacin in the plasma were measured using high-performance liquid chromatography (HPLC) with fluorescence detection on samples collected at frequent intervals after drug administration. Following intravenous injection, the decline in plasma drug concentration was bi-exponential with half-lives of (t_1/2α) 0.22 ± 0.10 h and (t_1/2β) 2.49 ± 0.26 h for distribution and elimination phases, respectively. The volume of distribution at steady-state (V_dss) was 1.02 ± 0.14 l kg^?1 and the total body clearance (Cl_tot) was 0.32 ± 0.11 l kg^?1 h^?1, respectively. After intramuscular and oral administration of moxifloxacin at the same dose the peak plasma concentrations (C_max) were 2.38 ± 0.43 and 2.11 ± 0.36 μg ml^?1 and were obtained at 1.47 ± 0.26 and 1.83 ± 0.16 h (T_max), respectively, the elimination half-lives (T_1/2el) were 3.14 ± 0.42 and 2.63 ± 0.44 h, respectively, and AUC_0–24 were 15.87 ± 2.35 and 14.52 ± 2.37 μg ml^?1 h^?1, respectively. The systemic bioavailabilities were 96.36 ± 11.54% and 86.79 ± 12.64%, respectively. In vitro plasma protein binding percent was 32%. We concluded that moxifloxacin might be clinically interesting alternative for the treatment of most sensitive bacterial infections in Muscovy ducks.     

Novel and simple approach using synthesized nickel nanoparticles to control blood-sucking parasites

The present study was on assessment of the anti-parasitic activities of nickel nanoparticles (Ni NPs) against the larvae of cattle ticks Rhipicephalus (Boophilus) microplus and Hyalomma anatolicum (a.) anatolicum (Acari: Ixodidae), fourth instar larvae of Anopheles subpictus, Culex quinquefasciatus and Culex gelidus (Diptera: Culicidae). The metallic Ni NPs were synthesized by polyol process from Ni-hydrazine as precursor and Tween 80 as both the medium and the stabilizing reagent. The synthesized Ni NPs were characterized by Fourier transform infrared (FTIR) spectroscopy analysis which indicated the presence of Ni NPs. Synthesized Ni NPs showed the X-ray diffraction (XRD) peaks at 42.76°, 53.40°, and 76.44°, identified as 1 1 1, 2 2 0, and 2 0 0 reflections, respectively. Scanning electron microscopy (SEM) analysis of the synthesized Ni NPs clearly showed that the Ni NPs were spherical in shape with an average size of 150 nm. The Ni NPs showed maximum activity against the larvae of R. (B.) microplus, H. a. anatolicum, A. subpictus, C. quinquefasciatus and C. gelidus with LC₅₀ values of 10.17, 10.81, 4.93, 5.56 and 4.94 mg/L; r² values of 0.990, 0.993, 0.992, 0.950 and 0.988 and the efficacy of Ni-hydrazine complexes showed the LC₅₀ values of 20.35, 22.72, 8.29, 9.69 and 7.83 mg/L; r² values of 0.988, 0.986, 0.989, 0.944 and 0.978, respectively. The findings revealed that synthesized Ni NPs possess excellent larvicidal parasitic activity. To the best of our knowledge, this is the first report on larvicidal activity of blood feeding parasites using synthesized Ni NPs.     

Simultaneous detection of the feline lungworms Troglostrongylus brevior and Aelurostrongylus abstrusus by a newly developed duplex-PCR

In addition to Aelurostrongylus abstrusus (Strongylida: Angiostrongylidae), referred to as the feline lungworm, Troglostrongylus brevior (Strongylida: Crenosomatidae) has recently been identified as an agent of bronco-pulmonary infestations in cats. These two parasites have a similar biology, share ecological niches, potentially co-infesting cats, but are difficult to be differentiated due to the morphological similarities of their first-stage larvae (L1). This paper describes a molecular tool, based on single-step duplex polymerase chain reaction (duplex-PCR) on the ribosomal internal transcribed spacer 2 region (ITS-2) for the simultaneous detection and differentiation of T. brevior and A. abstrusus. L1 of both species were collected from faecal samples, morphologically identified, and single larval specimens isolated. An aliquot of faeces was used as a test sample for a case of mixed natural infestation. The duplex-PCR was performed using species-specific forward primer sets for the ITS-2 region (i.e., A. abstrusus: 220 bp; T. brevior: 370 bp). The detection limit of the molecular assay was also assessed by serial dilutions of DNA from single larvae of both species (from ～4.0 to 4.0 × 10^?5 μg/μl). The duplex-PCR carried out on individual DNA samples was able to detect as low as 5.2 × 10^?3 μg/μl of DNA for A. abstrusus, 4.9 × 10^?3 μg/μl for T. brevior, and as low as 4.0 × 10^?3 μg/μl for samples containing both species. Species-specific bands of the expected sizes and two bands were simultaneously amplified from the faecal sample containing both species. The phylogenetic analyses of the ITS-2 sequences here examined and those available for other metastrongyloids were concordant in clustering them with those of other Troglostrongylus brevior and A. abstrusus sequences available in GenBank database. This molecular approach proved to be effective and highly sensitive for the simultaneous detection of the two lungworms species and it might be used for molecular epidemiological studies and for monitoring therapeutic protocols.     

Animal and Vegetation Response to Modified Intensive–Early Stocking on Shortgrass Rangeland

A comparison of animal gains and vegetation trends was made from 2002–2008 between a continuous season-long stocking (SLS) system and a modified intensive–early stocking system (IES) with late-season grazing (IES 1.6× + 1; 1.6 times the number of animals of the SLS system from May 1 to July 15, and 1 times the number of animals of SLS from July 15 to October 1) on shortgrass native rangeland of western Kansas. The continuous season-long stocked system placed animals at a density of 1.37 ha · steer^?1 from May through October, or 2.63 animal unit months (AUM) · ha^?1, whereas the intensive–early stocked system with late-season grazing (3.33 AUM · ha^?1) stocked pastures at 0.85 ha · steer^?1 from May through the middle of July, and then stocked pastures at 1.37 ha · steer^?1 for the remainder of the grazing season by removing the heaviest animals mid-July each yr. Average daily gains (0.78 vs. 0.70 kg · d^?1, P = 0.039) and total animal gain (58 vs. 52 kg, P = 0.042) were different between the continuous season-long stocked and the intensive–early stocked animals during the first half of the grazing season. No difference was found between average daily gain (0.61 vs. 0.62 kg · d^?1, P = 0.726) and total animal gain (48 vs. 49 kg, P = 0.711) for the continuous season-long stocked and intensive–early stocked with late-season grazing animals during the last half of the season. Total individual animal gain (106 vs. 101 kg, P = 0.154) and average daily gain (0.70 vs. 0.66 kg · d^?1, P = 0.152) was not different between the continuous season-long stocked and the intensive–early stocked system animals that were on pasture the entire grazing season. Total beef gain on a land-area basis (96 vs. 77 kg · ha^?1, P = 0.008) was greater for the modified intensive–early stocked system with late-season grazing with greater animal densities. Changes in residual biomass and most key vegetation components at the end of the grazing season were not different between the two systems.     

Stocking Rate and Fuels Reduction Effects on Beef Cattle Diet Composition and Quality

An experiment was conducted to evaluate the influence of forest fuels reduction on diet quality, botanical composition, relative preference, and foraging efficiency of beef cattle grazing at different stocking rates. A split plot factorial design was used, with whole plots (3 ha) being fuel reduced or no treatment (control), and split plots (1 ha) within whole plots were grazed to three levels of forage utilization; (low) 3 heifers · ha^?1, (moderate) 6 heifers · ha^?1, (high) 9 heifers · ha^?1, with a 48-h grazing duration. Grazing treatments were applied in August of 2005 and 2006. Cattle diet composition and masticate samples were collected during 20-min grazing bouts using six ruminally cannulated cows in each experimental unit. Relative preference indices indicated a strong preference for grass regardless of treatment and stocking rate. Grass consumption was lower in control pastures (P < 0.05) and tended (P < 0.095) to decrease with increased stocking rates. Shrub use was higher in control pastures displaying a quadratic effect (P < 0.05) due to stocking, whereas shrub use increased with stocking rate across all treatments. Cattle grazing control pastures consumed diets higher in crude protein compared to cattle grazing treated pastures (P < 0.05). In vitro dry matter digestibility values were lower (P < 0.05) in control sites and tended (P = 0.10) to decrease with increased stocking rates. In both control and treated pastures, bites per minute and grams consumed per minute declined (P = 0.003) with increased stocking, indicating foraging efficiency of cattle decreases with increased stocking rates. Our data indicated cattle grazing late season grand fir habitat types have a strong preference for grasses regardless of treatment or stocking rate. However, as stocking rate increased in both control and treated pastures, grass consumption decreased, shrub consumption increased, and foraging efficiency decreased.     

Antinociceptive efficacy and plasma concentrations of transdermal buprenorphine in dogs

To assess the antinociceptive efficacy of transdermal (TD) buprenorphine (B) in dogs, a prospective, positive-controlled experimental study was performed in 10 healthy Beagles. In an open label crossover design, the dogs initially received intravenous B (IVB, 0.02 mg kg^?1) as a positive control, followed by TDB (52.5 μg h^?1) 4 months later. Blood was collected at regular intervals for determination of the plasma concentrations of B ([B]) and its metabolite norbuprenorphine. The antinociceptive efficacy was assessed using thermal and mechanical models of nociception. The peak concentration [B] was 1.54 ng mL^?1 (±1.98) 60 h after TDB application, although three dogs had no measurable [B] after TDB. Maximum thermal threshold (TT) was 52.6 °C (±0.48) at 1 h after IVB administration and 51.63 °C (±1.01) 72 h after TDB application. The significant increase in TT indicated that effective antinociception was achieved beyond 36 h after the application of TDB, lasting until patch removal. There was hysteresis between [B] and the antinociceptive effect.     

Evaluation of in vitro and in vivo inhibitory effects of fusidic acid on Babesia and Theileria parasites

Fusidic acid known to has antibacterial, antifungal, and antimalarial activities. Fusidic acid blocks translation elongation factor G gene in Plasmodium falciparum. In the present study, the inhibitory effects of fusidic acid on the in vitro growth of bovine and equine Babesia parasites were evaluated. The inhibitory effect of fusidic acid on the in vivo growth of Babesia microti was also assessed. The in vitro growth of four Babesia species that were tested was significantly inhibited (P < 0.05) by micromolar concentrations of fusidic acid (IC₅₀ values = 144.8, 17.3, 33.3, and 56.25 μM for Babesia bovis, Babesia bigemina, Babesia caballi, and Theileria equi, respectively). Combinations of fusidic acid with diminazene aceturate synergistically potentiated its inhibitory effects in vitro on B. bovis and B. caballi. In B. microti-infected mice, fusidic acid caused significant (P < 0.05) inhibition of the growth of B. microti at the dose of 500 mg/kg BW relative to control group. These results indicate that fusidic acid might be incorporated in treatment of babesiosis.     

Immune responses of orange-spotted grouper,Epinephelus coioides,against virus-like particles of betanodavirus produced in Escherichia coli

Betanodaviruses are the causative agents of viral nervous necrosis (VNN), a serious disease of cultured marine fish worldwide. Virus-like particles (VLPs) are one of the good novel vaccine candidates to control this disease. Until now, betanodavirus vaccine studies mainly focused on the humoral immune response and mortality after virus challenge. However, little is known about the activation of genes responsible for cellular and innate immunity by vaccines. In the present study, VLPs of orange-spotted grouper nervous necrosis virus (OGNNV) were produced in prokaryotes and their ability to enter Asian sea bass cells was the same as native virus, suggesting that they possess a similar structure to OGNNV. VLPs immunogenicity was then determined by intramuscularly vaccinating Epinephelus coioides at different concentrations (1.5 or 15 μg g^?1 fish body weight, FBW) and immunizing frequencies (administration once, twice and thrice). A single vaccination with the dosage of 1.5 μg g^?1 FBW is enough to provoke high titer antibodies (average 3 fold higher than that of negative control) with strong neutralizing antibody titer as early as 1 week post immunization. Furthermore, quantitative PCR analysis revealed that eleven genes associated with humoral, cellular and innate immunities were up-regulated in the liver, spleen and head kidney at 12 h post immunization, correlating with the early antibody response. In conclusion, we demonstrated that VLP vaccination induced humoral immune responses and activated genes associated with cellular and innate immunity against betanodavirus infection in orange-spotted grouper.     

Resveratrol decreases oxidative burst capacity and alters stimulated leukocyte cytokine production in vitro

IntroductionResveratrol, a naturally-occurring phytophenol, has been shown to bolster immune surveillance and reverse immunosenescence in a dose dependent manner in rodents and humans. Although safety and pharmacokinetic studies have been completed in dogs, the immunomodulatory effects of resveratrol in dogs has not yet been investigated. The objective of this study was to determine the effect of resveratrol on canine innate immune system function in vitro. The hypothesis was that similar to other species, low concentrations of resveratrol would stimulate while high concentrations would depress innate immune system function.MethodsWhole blood was collected from six healthy, adult, client-owned dogs and was incubated with resveratrol at final concentrations of 6000 ng ml⁻¹, 3000 ng ml⁻¹, 1000 ng ml⁻¹, or control solution for 4 h. Following incubation, phagocytosis and oxidative burst were evaluated using flow cytometry, and LPS-, lipoteichoic acid (LTA) – and peptidoglycan (PG)-stimulated leukocyte production of TNF, IL-6, and IL-10 were measured using a canine specific multiplex assay.ResultsPhagocytosis was not altered by resveratrol at any concentration compared to control. However, while the number of PMNs capable of performing oxidative burst did not change, the robustness of the reaction following stimulation with Escherichia coli and PMA was reduced in a dose dependent manner. In addition, LPS-, LTA-, PG, and PBS-stimulated TNF production was increased following incubation with all concentrations of resveratrol compared to control, and this effect was dose dependent. LTA-stimulated IL-6 was increased with resveratrol compared to control. Furthermore, LTA-stimulated IL-10 was decreased with 6000 ng ml⁻¹ and 3000 ng ml⁻¹ concentrations of resveratrol and PG-stimulated IL-10 production was decreased with all concentrations of resveratrol compared to control. The LPS-, LTA-, and PG-stimulated TNF:IL-10 ratio was increased with 6000 ng ml⁻¹ of resveratrol compared to control and lower resveratrol concentrations.ConclusionWhile resveratrol was sparing to PMN phagocytosis, it reduced the robustness of PMN oxidative burst. Resveratrol also increased pro-inflammatory and decreased anti-inflammatory leukocyte cytokine production capacity in vitro. These data suggest that resveratrol supplementation may depress oxidative burst reactions while promoting pro-inflammatory leukocyte cytokine production and decreasing anti-inflammatory cytokine production. Based on these findings, further in vivo study regarding the effects of resveratrol on PMN oxidative burst capability and leukocyte cytokine production capacity are indicated prior to routine supplementation.     

Supplementing Guinea grass with fresh sweet potato foliage for milk production by Bunaji and N'Dama cows in early lactation

Forage from three sweet potato cultivars (A = TIS-87/0087; B = TIS-8164; C = TIS-2532.OP.1.13 at 30% daily dry matter intake), dried brewers' grains (DBG) and cottonseed meal (CSM) each at 2.5 kg were supplemented to Guinea grass (GG) to form four diets: Diet A = GG + TIS-87/0087; Diet B = GG + TIS-8164; Diet C = GG + TIS-2532.OP.1.13, and Diet D = GG + DBG + CSM (as control). Treatments were assigned as 4 × 4 Latin squares design over 60 days (10-day adaptation and 5-day sampling) using Bunaji and N'Dama cows in early lactation. The 48-h rumen dry matter (DM) degradation ranged (P < 0.01) from 407 g kg^? 1 DM for GG to 791 g kg^? 1 DM for sweet potato cultivar TIS-87/0087. Bunaji dry matter intake varied (P < 0.05) between 7.1 kg day^? 1 in Diet B and 8.9 kg day^? 1 in Diet D, but was similar (P > 0.05) among diets for the N'Dama cows. The metabolisable energy (ME) intakes were higher for Diet D although, it recorded the least efficiency of ME utilization for milk production. Milk yields were significantly (P < 0.01) higher in the Bunaji than the N'Dama cows, which is typical of their true breed differences. Total solids, ash, protein, fat, and sugar contents of the milk were similar among diets for both cow breeds, except Bunaji ash contents that ranged (P < 0.05) from 0.77 g 100 g^? 1 for Diet B to 0.83 g 100 g^? 1 for Diet D. The results suggest that sweet potato forage could be utilized as whole or partial replacement for DBG and CSM to save cost under smallholder farming systems.     

Performance of spring-calving beef suckler cows and their progeny to slaughter on intensive and extensive grassland management systems

The performance of rotationally grazed beef suckler cows and their progeny to slaughter on two lowland grassland management systems differing in stocking rate (SR) and fertiliser nitrogen (N) level was compared over eight years. The two Systems were 1) Intensive (INT): SR of 0.56 (bull production) or 0.71 (steer production) ha cow^? 1 unit, 211 kg fertiliser N ha^? 1, two silage harvests, and 2) Extensive (EXT): SR of 0.69 (bull production) or 0.88 (steer production) ha cow^? 1 unit, 97 kg fertiliser N ha^? 1 and one staggered silage harvest. A cow unit was defined as a cow plus progeny to slaughter. On the silage harvesting area, the mean application rate for fertiliser N was 110 and 80 kg ha^? 1 for first and second harvests, respectively. Herbage dry matter digestibility both pre- and post-grazing was similar (P > 0.05) for the two systems, whereas herbage crude protein concentrations were generally significantly lower for the EXT than the INT system. There was no difference (P > 0.05) between the Systems in cow live weight, body condition score or their changes or in calf live weight gain from birth to weaning. Post-weaning, live weight gain, slaughter weight, carcass weight, kill-out proportion, estimated carcass gain, carcass conformation score or carcass fat score did not differ (P > 0.05) between the systems for heifer, steer or bull progeny. It can be concluded that similar animal performance levels can be expected in an extensive grassland-based suckler calf-to-beef system compatible with the EU, Rural Environmental Protection Scheme as that attained in a more intensive System comprising of both a moderately high SR (~ 1.25 higher) and fertiliser N application (~ 2.1 higher).     

A comparison of three different methodologies for evaluating Rhipicephalus (Boophilus) microplus susceptibility to topical spray compounds

This study aimed to compare three different methodologies (Adult Immersion Tests, field trials with naturally infected animals, and a Stall Test using artificially infested cattle) to evaluate the efficacy of two topical formulations that we administered as whole body sprays (15% Cypermethrin + 30% Chlorpyriphos + 15% Fenthion–Colosso^® FC 30, Ouro Fino Agronegócios; and 60% Dichlorvos + 20% Chlorpyriphos–Ectofós^®, Vallée Saúde Animal Ltd.), against a susceptible strain of Rhipicephalus (Boophilus) microplus. To achieve this objective, two natural infestation trials were conducted, as well as two artificial infestation trials (Stall Tests) and two Adult Immersion Tests (AIT). The AIT results showed that both spray formulations achieved 100% efficacy against R. (B.) microplus fully engorged females. However, when observing results obtained by field trials (natural infestations) and Stall Tests, none of these topically applied compounds reached 100% efficacy or affected the reproductive capacity of the fully engorged female ticks. Additional studies must be conducted to compare these in vivo methodologies with different in vitro techniques, such as the Larval Packet Test. However, based on results obtained here, we can conclude that depending on the spray formulations used, the AIT can overestimate acaricidal efficacy and values of reproductive efficiency of such compounds against R (B.) microplus. Specifically, when dealing with spray formulations in the Stall Tests, the period of residual action can increase because these animals are sheltered from contact with environmental factors that might interfere with the efficacy of the products tested. It may be necessary to take in vivo trial results into consideration (such as field trials with naturally infested animals or Stall Tests) to standardize a specific in vitro assay, such as the Adult Immersion Test.     

Essential oil of Aloysia citriodora Paláu and citral: sedative and anesthetic efficacy and safety in Rhamdia quelen and Ctenopharyngodon idella

ObjectiveTo verify the efficacy of citral in inducing sedation and anesthesia in silver catfish (Rhamdia quelen) and grass carp (Ctenopharyngodon idella) and to assess the safety of essential oil (EO) of Aloysia citriodora and citral in inducing and maintaining anesthesia in silver catfish.Study designClinical study, randomized, parallel, multi-arm with control group in target species.AnimalsA total of 96 juvenile and 72 adult silver catfish and 80 juvenile grass carp were used.MethodsSilver catfish and grass carp were exposed to different concentrations of citral, 15–675 and 15–600 μL L^–1, respectively, during the maximum period of 30 minutes to verify sedation and anesthesia induction and recovery times. In addition, for anesthetic induction, silver catfish were exposed to the EO of A. citriodora and citral at 225 μL L^–1 for 3.5 minutes. Then, fish were transferred to an anesthesia maintenance solution at 50 μL L^–1 for 10 minutes to assess hematologic and biochemical variables at 60 minutes, 2 and 6 days after treatment.ResultsCitral only induced sedation from 15, 25 and 40 μLL^–1 in both species. Anesthesia without mortality was induced in silver catfish at 50–600 μL L^–1 and grass carp at 75–450 μL L^–1. At 675 and 600 μL L^–1, mortality was recorded in silver catfish and grass carp, respectively. The EO of A. citriodora and citral were safe in inducing and maintaining anesthesia in silver catfish, with mean corpuscular hemoglobin concentration being the only variable that varied in relation to time and treatments.Conclusions and clinical relevanceCitral was effective in inducing sedation and anesthesia in both species. In addition, A. citriodora EO and citral were safe in inducing and maintaining anesthesia in silver catfish. Both agents are promising substances for the development of new drugs for fish.     

Identification and characterization of serum complement activity in the American crocodile (Crocodylus acutus)

Incubation of unsensitized sheep red blood cells with serum from the American crocodile (Crocodylus acutus) resulted in a concentration-dependent hemolysis. The hemolytic activity was heat-sensitive, and inhibited by EDTA in a concentration-dependent manner. The EDTA-inhibited SRBC hemolysis could be restored by the addition of excess Ca²⁺ or Mg²⁺, but not Ba²⁺ or Cu²⁺, revealing the specificity of this activity for these two divalent cations. The hemolytic activity of crocodile serum was titer-dependent, with 329 μL producing 50% of maximal SRBC hemolysis. The complement activity was also temperature-dependent, with decreased activity at lower temperatures (5–15 °C) and maximal activity occurred at 30–40 °C. The hemolysis occurred relatively slowly, with near zero activity after 10 min, 40% of activity observed within 15 min of exposure to SRBCs, and maximal activity at 30 min.     

Effect of molecular weight and concentration of legume condensed tannins on in vitro larval migration inhibition of Haemonchus contortus

The effect of molecular weight of condensed tannins (CT) from a variety of warm-season perennial legumes commonly consumed by sheep and goats on anthelmintic activity has not been previously explored. The objectives of this study were to determine if molecular weight of CT from warm-season perennial legumes could predict the biological activity of CT relative to anthelmintic activity against ivermectin resistant L3 stage Haemonchus contortus (HC) using a larval migration inhibition (LMI) assay. A second objective was to determine if CT from warm-season perennial legumes possess anthelmintic properties against L3 stage (HC). Lespedeza stuevei had the greatest concentration of total condensed tannin (TCT; 11.7%), whereas, with the exception of Arachis glabrata, a CT-free negative control, Leucaena retusa had the least TCT (3.3%). Weight-average molecular weight of CT ranged from 552 Da for L. stuevei to 1483 Da for Lespedeza cuneata. The treatments demonstrating the greatest percent LMI were L. retusa, L. stuevei and Acacia angustissima var. hirta (65.4%, 63.1% and 42.2%, respectively). The ivermectin treatment had the smallest percent LMI (12.5%) against ivermectin resistant L3 HC. There was a weak correlation (R² = 0.34; P = 0.05) between CT M_W and percent LMI, suggesting that molecular weight of CT is a weak contributing factor to CT biological activity as it relates to LMI of L3 stage HC. L. stuevei, L. retusa and A. angustissima var. hirta STP5 warrant further evaluation of anthelmintic properties in vivo.