Screening of microfilaricidal effects of plant extracts against Dirofilaria immitis

Canine dirofilariasis is a common tropical parasitic disease of companion animals, caused by infestation of Dirofilaria immitis filarids within the pulmonary arteries and extending into the right heart. Increased reports of adverse reactions elicited by current microfilaricidal agents against D. immitis such as neurological disorders, circulatory collapse and potential resistance against these agents, warrant the search for new agents in forms of plant extracts. The use of plant extracts in therapeutic medicine is commonly met with scepticism by the veterinary community, thus the lack of focus on its medical potential. This study evaluated the presence of microfilaricidal activities of the aqueous extracts of Zingiber officinale, Andrographis paniculata and Tinospora crispa Miers on D. immitisin vitro at different concentrations; 10 mg/ml, 1 mg/ml, 100 μg/ml, 10 μg/ml and 1 μg/ml within 24 h, by evaluation of relative microfilarial motility as a measure of microfilaricidal activity. All extracts showed microfilaricidal activity with Z. officinale exhibiting the strongest activity overall, followed by A. paniculata and T. crispa Miers. It is speculated that the microfilaricidal mechanism exhibited by these extracts is via spastic paralysis based upon direct observation of the microfilarial motility.     

Purification of cattle oviduct specific proteins and their effect on in vitro embryo development

The purpose of this study was to determine the effect of oviduct specific proteins as a media supplement for in vitro embryo development in cattle. The proteins were extracted from oviducts of cows and precipitated by ammonium sulfate (30%, 40%, 50% and 60%) followed by dialysis in 50 mM Tris–HCl (pH 7.0) buffer. The dialyzed proteins were fractionated into acidic, basic and neutral fractions using SP sephadex cation exchange and DEAE sephadex anion exchange column chromatography respectively. Cow oviduct specific proteins (cOSPs) constituting all the extracted proteins were used as media supplement in three different concentrations (10, 50 and 100 μg/ml) for in vitro maturation, fertilization and culture (IVMFC) of cow oocytes. Acidic, basic and neutral (unbound) fractions were also used as media supplement in three different concentrations (10, 30 and 50 μg/ml) for IVMFC. Cumulus oocytes complexes were collected from slaughterhouse ovaries, washed thoroughly and cultured in maturation media for 24 h in 5% CO₂ at 38.5 °C with maximum humidity. In vitro matured oocytes were co-incubated with in vitro capacitated sperm in Fert-BO media at 38.5 °C for 18 h in 5% CO₂. The fertilized oocytes were washed and cultured in embryo development media for cleavage. After 40–42 h cleavage was observed and embryos were put in the replacement media for further development. The cleavage rates (%) for cOSPs were observed as 68.24±2.46, 69.28±2.05, 61.77±0.93 and 42.62±1.31 at concentrations of 0, 10, 50 and 100 μg/ml respectively. Rates of blastocyst stage development were 14.49±3.61, 21.17±2.77, 14.66±1.06 and 11.98±1.84. These results indicate that addition of cOSP at10 μg/ml increased blastocyst formation as compared to other concentrations (0, 50 and 100 μg/ml). Although acidic, basic and neutral fractions seemed to have no major effect on cleavage rate, but both acidic and neutral fraction of oviduct specific proteins improved the cleavage rate at 30 μg/ml concentration and basic fraction improved the blastocyst formation at 10 μg/ml concentration.     

Antimicrobial susceptibility testing of Spanish field isolates of Brachyspira hyodysenteriae

This study is the first conducted in Spain to evaluate antimicrobial susceptibility of field isolates of Brachyspira hyodysenteriae. One hundred and eight isolates of the bacterium, recovered from different Spanish swine farms between 2000 and 2007, were investigated. The minimum inhibitory concentrations (MIC) of erythromycin, tylosin, tiamulin, valnemulin, clindamycin and lincomycin were determined using a broth microdilution technique. Most of the isolates showed poor susceptibility to erythromycin (MIC₉₀ > 256 μg/ml), tylosin (MIC₉₀ > 256 μg/ml), clindamycin (MIC₉₀ > 4 μg/ml) and lincomycin (MIC₉₀ = 128 μg/ml). Reduced susceptibility to tiamulin and valnemulin was observed with a MIC > 2 μg/ml in 17.6% and 7.41% of the B. hyodysenteriae isolates, respectively. Moreover, a survival analysis permitted the detection of an increasing trend in the MIC values for almost all the antimicrobials used in the treatment of swine dysentery when comparing recent isolates (from 2006 to 2007) with those recovered in earlier years (between 2000 and 2004).     

Evaluation of the in vitro growth-inhibitory effect of epoxomicin on Babesia parasites

Epoxomicin potently and irreversibly inhibits the catalytic activity of proteasomal subunits. Treatment of proliferating cells with epoxomicin results in cell death through accumulation of ubiquinated proteins. Thus, epoxomicin has been proposed as a potential anti-cancer drug. In the present study, the inhibitory effects of epoxomicin on the in vitro growth of bovine and equine Babesia parasites were evaluated. The inhibitory effect of epoxomicin on the in vivo growth of Babesia microti was also assessed. The in vitro growth of five Babesia species that were tested was significantly inhibited (P < 0.05) by nanomolar concentrations of epoxomicin (IC₅₀ values = 21.4 ± 0.2, 4 ± 0.1, 39.5 ± 0.1, 9.7 ± 0.3, and 21.1 ± 0.1 nM for Babesia bovis, Babesia bigemina, Babesia ovata, Babesia caballi, and Babesia equi, respectively). Epoxomicin IC₅₀ values for Babesia parasites were low when compared with diminazene aceturate and tetracycline hydrochloride. Combinations of epoxomicin with diminazene aceturate synergistically potentiated its inhibitory effects in vitro on B. bovis, B. bigemina, and B. caballi. In B. microti-infected mice, epoxomicin caused significant (P < 0.05) inhibition of the growth of B. microti at the non-toxic doses of 0.05 and 0.5 mg/kg BW relative to control groups. Therefore, epoxomicin might be used for treatment of babesiosis.     

Anthelmintic activity of Cocos nucifera L. on intestinal nematodes of mice

In this study, we evaluated the anthelmintic activity of the liquid extracted from the bark of the green coconut (LBGC), as well as butanol extract obtained from LBGC, on mouse intestinal nematodes. Thirty-six naturally infected mice were distributed into six groups receiving the following treatments: Group I: 1000 mg/kg of LBGC; Group II: 2000 mg/kg of LBGC; Group III: 500 mg/kg of butanol extract; Group IV: 1000 mg/kg of butanol extract; Group V: 0.56 mg/kg febendazole; and Group VI: 3% dimethylsulfoxide. The chemical composition of the LBGC and its butanol extract was determined by phytochemical tests. A dose of 1000 mg/kg of butanol extract had 90.70% efficacy in reducing the mouse worm burden (p < 0.05). Phytochemical tests revealed the presence of triterpens, saponnins and condensed tannins in the LBGC and butanol extracts. These results suggest that Cocos nucifera extracts may be useful in the control of intestinal nematodes.     

Effects of anesthetic protocols on electroejaculation variables of Iberian ibex (Capra pyrenaica)

The effects of three intramuscular anesthesia protocols - detomidine 190 μg/kg plus ketamine 2 mg/kg, detomidine 270 μg/kg plus ketamine 1.4 mg/kg, and tiletamine 3.4 mg/kg plus zolazepam 3.4 mg/kg - on penis protrusion and ejaculation variables were compared in nine captive Spanish ibex (Capra pyrenaica) subjected to electroejaculation. Body temperature, heart, and respiratory rates, as well as a number of plasma biochemical variables were also recorded prior to and during anesthesia. The detomidine plus ketamine protocols induced bradycardia and increased respiratory rate. However, the tiletamine/zolazepam protocol did not affect heart and respiratory rates. None of the three protocols caused a substantial change in rectal temperature, yet all protocols caused a significant increase in plasma glucose levels. Differences in anesthetic protocols did not affect sperm quality or quantity. However, choice of anesthetic protocol affected (P < 0.05) the degree of penis protrusion and the electrical pulse sequence required to achieve ejaculation. Results of this study support a recommendation of detomidine 270 μg/kg plus ketamine 1.4 mg/kg for anesthesia of Spanish ibex undergoing electroejaculation.     

Yeast extract, brewer’s yeast and spirulina in diets for Labeo rohita fingerlings affect haemato-immunological responses and survival following Aeromonas hydrophila challenge

A feeding trial was conducted for 60 days to study the immunomodulatory role of three different immunostimulants yeast extract (YE), brewer’s yeast (BY) and spirulina (SP) in Labeo rohita fingerlings. Four hundred and fifty fingerlings (avg. wt 3.35 ± 0.15 g) were randomly distributed in ten treatments and fed with either of ten iso-nitrogenous and iso-caloric semi-purified diets, prepared with three incremental levels (1%, 2% and 4%) of different immunostimulants except the control. Growth parameters did not vary significantly (p > 0.05) among the experimental groups. Haematology and serum parameters was performed before Aeromonas hydrophila challenge whereas respiratory burst activity was analysed following challenge. The respiratory burst activity, total leucocyte count, serum total protein and globulin was significantly higher (p < 0.05) in YE 1% supplemented group. The survival (%) after challenging with A. hydrophila was also highest in the YE fed groups. The results indicate that among the different sources and levels of immunostimulants, YE at lower inclusion level is more effective in promoting the immune status of L. rohita fingerlings.     

Quantitative real-time PCR and culture examination of Mycobacterium avium subsp. paratuberculosis at farm level

Mycobacterium avium subsp. paratuberculosis (MAP) causes Johne's disease in ruminants and may contribute to Crohn's disease in humans. The aim of this study was to determine the occurrence and quantity of MAP in cattle feces and milk in the Iranian context. In addition, we evaluated the effect of cattle age as well as farming system as risk factors contributing to MAP load. For this, a total sample of 373 consisting of 150 cattle feces (CF), 150 individual cow's milk (ICM), as well as 73 bulk-tank milk (BTM) was collected randomly and regardless of the cattle health status. The samples were assayed using F57 quantitative real-time PCR (qPCR) and culture method. According to the results of qPCR which was found ∼10 times more sensitive than culture assay, MAP was detected in 68.66% (103/150) of the CF, 12% (18/150) of the ICM and 52.05% (38/73) of the BTM samples. In contrast to the previous reports, the quantity of MAP in the BTM (2.03–5.97 log cfu/50 ml) was statistically (p < 0.01) higher than the ICM (0.90–1.97 log cfu/50 ml). Data suggested a direct relation (p < 0.01) between the cattle age and the quantity of MAP in the CF samples, while the relation was not statistically significant (p > 0.05) for the ICM. In addition, MAP load in the BTM samples obtained from traditional farms was significantly (p < 0.01) higher than that of the industrial ones, while the differences in CF and ICM was not significant (p > 0.05).     

The onset of puberty of Pelibuey male hair sheep is not delayed by the short term consumption of Morus alba or Hibiscus rosa-sinensis foliage

The present trial evaluated the effect of phytoestrogens consumed from Mulberry (Morus alba) or Hibiscus (Hibiscus rosa-sinensis) foliage, on the onset of puberty of Pelibuey male lambs. The design of the study aimed at identifying possible acute changes on the onset of puberty. Eighteen male lambs were used (107±9 days of age, 16±3 cm scrotal circumference (SC), 3.4±0.1 body condition score (BCS) and 17±1 kg bodyweight (BW)). At weaning, the lambs were distributed in three groups (n=6 each): (i) Control group (balanced feed based on grains+star grass), (ii) Mulberry Group (Mulberry foliage+balanced feed) and (iii) Hibiscus Group (Hibiscus foliage+balanced feed). BW, SC and body condition score (BCS) were determined every 14 days. An estrogenized adult female was used to attempt the collection of semen samples from the males two times per week. The onset of puberty was determined as the presence of sperm showing progressive movement in the ejaculate. From then, semen collections continued in the males (once a week) until the first normal ejaculate was obtained. The nutritional value of the foliages, as well as the content of total phenols, total tannins and condensed tannins, was determined. The phytoestrogen content (Equol, 4′7-dimetoxyisoflavone, Genistein, Rutin and Ononin) was determined from the methanolic extract of both plants. Total dry matter consumptions were similar between the Control and Mulberry groups and both were higher than the Hibiscus group (P<0.05). The total consumption of phytoestrogens and tannins was similar in the Mulberry and the Hibiscus group. The short-term consumption of phytoestrogens from Mulberry or Hibiscus foliage failed to delay the onset of puberty. The mean age at the onset of puberty was similar in the three groups (146 days in the control and Mulberry groups and 154 days in the Hibiscus group; P>0.05). The mean age at the first normal ejaculate was also similar between groups (167 days for Mulberry and Hibiscus groups and 169 days in the control group; P>0.05). The BW (Control: 21.6±3.1; Mulberry: 20.7±1.9; Hibiscus: 19.8±2.8 kg), the BCS and the SC were similar between groups at the onset of puberty. The present trial showed that a short exposure to M. Alba or H. rosa-sinensis foliage through diet did not influence the onset of puberty of Pelibuey male lambs.     

The efficacy of eprinomectin extended-release injection against Hypoderma spp. (Diptera: Oestridae) in cattle

The efficacy of eprinomectin in an extended-release injection (ERI) formulation was determined in cattle harboring naturally acquired infestations of first- or second- and third-stage larvae of Hypoderma spp. in three studies conducted according to the same protocol in the USA (two studies) and Germany (one study). Thirty cattle sourced from herds with a history of Hypoderma infestation were included in each study. Cattle were formed into replicates of three animals each on the basis of pre-treatment anti-Hypoderma antibody titers. Within replicates each animal was randomly allocated to one of the following treatments: ERI vehicle (control) at 1 mL/50 kg bodyweight, administered once on Day 0; Eprinomectin 5% ERI at 1 mL/50 kg bodyweight (1.0 mg eprinomectin/kg), administered once on Day 0 (when larvae were expected to be first instars); or Eprinomectin 5% ERI at 1 mL/50 kg bodyweight (1.0 mg eprinomectin/kg), administered once when larvae were second or third instars (study dependent, Day 73, 119, or 140). Treatments were administered by subcutaneous injection in front of the shoulder. In all studies, emerging and/or expressed Hypoderma larvae were recovered, speciated, and counted and viability was determined. Eprinomectin LAI treatment was 100% (p < 0.05) efficacious against first- and second- or third-stage larvae of Hypoderma bovis (two studies) and Hypoderma lineatum (one study). All animals accepted the treatment well. No adverse reaction to treatments was observed in any animal in any study.     

Assessing the efficacy of Duddingtonia flagrans chlamydospores per gram of faeces to control Haemonchus contortus larvae

The aims were (a) to quantify the number of Duddingtonia flagrans chlamydospores per gram of faeces (CPG) recovered from sheep administered with different oral doses and, (b) to describe the relationship between CPG and eggs per gram of faeces (EPG) on the efficacy to reduce Haemonchus contortus infective larvae. Three doses of chlamydospores per kg BW were orally administered during seven days: (T1) non treated control group, (T2) 1 × 10⁶, (T3) 2.5 × 10⁶ and (T4) 5 × 10⁶. Three lambs, infected with H. contortus, were used per group. Faeces were obtained from the rectum of each lamb during the fungal administration period (days 0–6) and for six days after that period. Four coproculture replicates were made from each animal in days 2, 4, 6, 8 and 10. A higher chlamydospore dose produced higher CPG in faeces (p < 0.05), but a clear dose dependent effect was not found either in the larvae reduction or in the CPG:EPG ratio. When ratios were re-analyzed, independently of the treatment groups of origin, a better efficacy was obtained with a ratio from 5 to 10 CPG:EPG and a higher ratio (>10 per egg) showed a lower reduction efficacy (p < 0.05). The binomial analysis showed that for each unit of increment in CPG:EPG ratio there was a reduction of larvae number until a point (between 5 and 10 CPG:EPG) where no further reduction was detected. The surface response test indicated that the number of larvae was reduced by CPG until possible saturation. The highest CPG:EPG ratios did not necessarily improve efficacy of D. flagrans.     

Cytotoxicity of Senecio in macrophages is mediated via its induction of oxidative stress

In Arunachal Pradesh and other sub-Himalayan areas of India, accidental consumption of Senecio plants by yaks is often fatal as the plant contains toxic alkaloids like Seneciophylline. The present investigation was undertaken to demonstrate the pro-oxidant effects of an ethanolic extract of Seneciochrysanthemoides (S-EtOH). S-EtOH impaired viability in macrophages, the IC₅₀ being 13.8 ± 1.11 μg/mL. The effect of S-EtOH (1 μg/mL) on generation of reactive oxygen species (ROS) in macrophages was measured by flow cytometry using 2′,7′-dichlorofluorescein diacetate (H₂DCFDA) where it caused a significant increase in the mean fluorescence channel (MFC) from 8.55 ± 0.03 to 47.32 ± 2.25 (p < 0.001). S-EtOH also effected a 3.8-fold increase in extracellular nitric oxide (NO) generation from 4.90 ± 0.72 μM to 18.79 ± 0.32 μM (p < 0.001), a 2.2-fold increase in intracellular NO production, the MFC increasing from 14.95 ± 0.48 to 33.34 ± 1.66 (p < 0.001), and concomitantly depleted non protein thiols as analyzed by flow cytometry using mercury orange, with a reduction in MFC from 632.5 ± 49.44 to 407.4 ± 12.61 (p < 0.01). Additionally, S-EtOH (14 μg/mL, 24 h) caused apoptosis as evident by increased Annexin V binding and terminal deoxynucleotidyl transferase mediated dUTP DNA nick end labeling. Taken together, the cytotoxicity of S-EtOH can be partly attributed to its capacity to inflict oxidative damage via generation of both reactive oxygen and nitrogen species culminating in apoptosis.     

Efficiency of entomopathogenic fungi in the control of eggs and larvae of the horn fly Haematobia irritans (Diptera: Muscidae)

The present study assessed the pathogenic effect of isolates E9, IBCB425 and IBCB159 of the Metarhizium anisopliae fungus, JAB06, JAB07 and AM09 of Beauveria bassiana, IBCB133 and CB75 of Isaria fumosorosea (=Paecilomyces fumosoroseus) and CG189 and CG195 of Isaria farinosa (=Paecilomyces farinosus) against eggs and larvae of the horn fly Haematobia irritans. Eggs were inoculated with suspensions containing 10⁶, 10⁷ and 10⁸ conidia ml⁻¹ of the fungal isolates and observed after 48 h to determine viability. In the larvae study, eggs were allowed to hatch into fresh bovine feces that had been treated with 10⁸, 10⁷ or 10⁶ conidia mg feces⁻¹. In both studies, 5 days after initial procedures, all formed pupae were transferred to an incubator at 27 ± 0.5 °C until the emergence of the adult flies was complete. The M. anisopliae isolates did not cause the death of H. irritans eggs, but they did promote the death of larvae that hatched from treated eggs, and therefore increased the total mortality. Isolate E9 promoted 100% mortality of treated larvae at a concentration of 10⁸ conidia ml⁻¹. For the B. bassiana isolates, no activity was observed against insect eggs or larvae. Both I. fumosorosea isolates promoted significant mortality (p < 0.05) of eggs at every concentration of conidia. Isolate CG195 of I. farinosa increased the mortality of larvae and pupae that hatched from treated eggs and promoted significant total mortality (p < 0.05) of the insect at every concentration of conidia.     

Effect of coconut oil and garlic powder on in vitro fermentation using gas production technique

An in vitro gas technique trial was conducted to investigate the effect of coconut oil (Co), garlic powder (G) and their mixtures on in vitro fermentation. Incubation was carried out using rumen fluid obtained from swamp buffaloes. The experimental design was a completely randomized design (CRD). The dietary treatments were ratio of Co and G supplementation at 0:0, 16:0, 8:4, 4:8 and 0:16 mg with rice straw as a roughage source. Cumulative gas production was recorded at 0, 2, 4, 6, 8, 12, 18, 24, 36, 48, 60 and 72 h of incubation. In vitro true digestibility (IVTD) was determined after 48 h incubation. Cumulative gas production at 72 h was significantly lowest (P < 0.05) at Co:G, 16:0 mg. Garlic powder supplementation at 16 mg decreased (P < 0.05) NH₃–N concentration and increased (P < 0.05) in vitro true digestibility (IVTD) while supplemented coconut oil at 16 mg decreased (P < 0.05) IVTD. Total volatile fatty acids (VFAs) were lowest (P < 0.05) by garlic powder supplementation at 16 mg. However, supplementation of Co:G, 8:4, 4:8 and 0:16 mg tended to increase the proportion of propionate, decrease C2:C3 ratio and reduce (P < 0.05) methane (CH₄) production. Protozoal population was significantly lowest (P < 0.05) at Co:G, 8:4 mg. Moreover, application of quantitative PCR to quantify predominant cellulolytic bacteria (16S rRNA) and fungi (18S rRNA) targets revealed that treatments did not have an effect on Ruminococcusflavefaciens and total fungi population. However, it was found that supplementation of Co:G at 8:4 mg increased Ruminococcusalbus population (P < 0.05). Based on this study, it suggests that supplementation of Co:G at 8:4 and 0:16 mg could improve ruminal fluid fermentation in terms of volatile fatty acid profile, reduced methane losses and reduced protozoal population.     

Evaluation on the pathogenicity of Erysipelothrix tonsillarum for pigs by immunosuppression with cyclophosphamide or dexamethasone

The pathogenicity of Erysipelothrix tonsillarum was evaluated in pigs immunosuppressed with cyclophosphamide (CY) or dexamethasone (DM). Animals were treated with 15 mg/kg CY (n = 8, five injections), 1 mg/kg DM (n = 8, nine injections) or left untreated (n = 8). On the fifth day after the beginning of drug treatments, swine were inoculated with one of two E. tonsillarum serovar 7 strains (approximately 10⁶ CFU per pig). In the CY-treated group, both circulating neutrophil and lymphocyte counts decreased, whereas in the DM-treated group, lymphocyte counts decreased but neutrophil counts increased. During the observation period, none of the CY- or DM-treated pigs developed clinical signs or gross lesions, as well as non-treated pigs. Growth agglutination antibody titres in all pigs remained unchanged. Our findings indicate that E. tonsillarum strains are avirulent for swine, regardless of immune status.     

Synergetic effects of oral administration of levamisole and Echinacea purpurea on immune response in Wistar rat

This research investigated the effects of levamisole and Echinacea purpurea (EP), separately and together on the immune response of the rat as a laboratory model. In this experiment, 40 male Wistar rats were obtained and divided into four groups (n = 10). These groups received normal saline (10 mg/kg), EP (500 mg/kg), levamisole (2 mg/kg) and EP (500 mg/kg) with levamisole (2 mg/kg) as oral gavages every day for a period of 4 weeks, respectively. After obtaining blood samples (at the end of each week), haematocrit (HCT), differential and total white blood cell (WBC) counts, phagocyte activity (number), total protein, albumin and globulins levels of samples were obtained. The results of the study showed that the gamma globulin level, WBC, neutrophil and monocyte counts and phagocyte activity increased significantly in comparison with normal saline group during the study. According to the results, each of the mentioned agents had a stimulant effect on the immune system separately and together on rats. In the group that received EP and levamisole simultaneously, these effects were synergistically increased. These compounds, by increasing the mentioned factors, will probably affect the immune system.     

Equine Endometrial Tissue Concentration of Fluconazole Following Oral Administration

The objective of this study was to determine the plasma and endometrial tissue concentrations of orally administered fluconazole and to determine if these tissue levels surpassed the minimum inhibitory concentration (MIC) for Candida spp. organisms in the reproductive tract of the mare. Mares from study 1 (n = 9) were administered a single oral loading dose of 14 mg/kg fluconazole. Plasma and endometrial tissue samples were collected before fluconazole administration and for 24 hours after the loading dose. Study 2 mares (n = 3), a subset of study 1, were administered the loading dose, followed by maintenance doses of 5 mg/kg every 24 hours for 6 days. Plasma and biopsy samples were collected for 48 hours after the last maintenance dose. High pressure liquid chromatography-tandem mass spectrometry was used to determine the concentration of fluconazole in all samples. The mean plasma and endometrial fluconazole levels 24 hours after the loading dose were 9.53 ± 0.824 μg/mL (mean ± standard deviation) and 11.3 ± 2.38 μg/g, respectively. Fluconazole levels in plasma and endometrial tissue 24 hours after the last maintenance dose were 7.82 ± 1.81 μg/mL and 7.23 ± 3.86 μg/g, respectively. Oral fluconazole administered as a 14-mg/kg loading dose and a 5-mg/kg maintenance dose every 24 hours will result in endometrial tissue levels near the accepted MIC values for most Candida spp. and surpass the MIC for Candida albicans in the reproductive tract of the mare. Consequently, this dosage regimen could be considered for the treatment of infectious endometritis caused by susceptible fungal organisms of Candida spp. in the mare.     

Pediococcus acidilactici isolated from the rumen of lambs with rumen acidosis, 16S rRNA identification and sensibility to monensin and lasalocid

A lactic-acid producing bacterium was isolated from the rumen of lambs with rumen acidosis. The cells were Gram-positive, nonmotile, nonsporing, catalase negative spherical, 1.5-2.0 μm in diameter, and occur in pairs and tetrads. Analysis of 16S ribosomal RNA indicated that the rumen bacterium was a strain of Pediococcus acidilactici with 99% of nucleotide homology. This bacterium was sensible to monensin and lasalocid at the unique dose tested of 300 ppm. The concentration of lactic acid and DM degradation decreased (P < 0.05) when monensin or lasalocid were added to the culture media after 24, 48 and 72 h of incubation. In contrast, total VFA concentration and pH were higher (P < 0.05) in the culture media added with the ionophores. Up to now S. bovis is considered the main ruminal bacterium related with rumen acidosis, but the importance of P. acidilactici should be also reconsidered in experimental studies focused on the control rumen acidosis.     

Chemical composition of Eucalyptus spp. essential oils and their insecticidal effects on Lutzomyia longipalpis

The chemical composition of essential oils from three species of plants belonging to the Eucalyptus genus was determined and, their insecticidal effects on egg, larva and adult phases of Lutzomyia longipalpis were assessed. The insects were collected in the municipality of Sobral in the State of Ceará, Brazil. Five treatments with different concentrations were performed along with two negative controls, distilled water and Tween 80 (3%), and a positive control, cypermethrin (0.196 mg/ml). The tests were carried out in plastic pots internally coated with sterile plaster and filled with a substrate made of rabbit feces and crushed cassava leaves. The eggs, larvae and adults were sprayed with the oils. The hatched larvae were counted for 10 consecutive days and observed until pupation. Insect mortality was observed after 24, 48 and 72 h. E. staigeriana oil was the most effective on all three phases of the insect, followed by E. citriodora and E. globulus oils, respectively. The major constituents of the oils were Z-citral and alpha-citral (E. staigeriana), citronellal (E. citriodora) and 1,8-cineole (E. globulus). The Eucalyptus essential oils constitute alternative natural products for the control of L. longipalpis since the median effective concentration (EC₅₀) values revealed relevant action as compared with other natural products, some of their chemical constituents are already known for their insecticidal activity and these oils are produced in commercial scale in Brazil.     

Combined subcutaneous administration of ivermectin and nitroxynil in sheep: Age/body weight related changes to the kinetic disposition of both compounds

The effect of age/body weight in the plasma disposition kinetics of ivermectin (IVM) and nitroxynil (NTX) after their co-administration as a combined formulation to sheep was studied. Sixteen (16) male sheep were allocated into two experimental groups (n = 8 each): (a) high body weight (high bw) (18-20 months old), and (b) low body weight (low bw) (6-8 months old). Animals in both groups were subcutaneously (sc) treated with IVM (200 μg/kg) and NTX (10 mg/kg) using a commercially available combined formulation (Nitromectin^®, Lab. Ovejero, Spain). Blood samples were taken by jugular venopuncture before (time 0), at 2, 4, 8, 12 h and at 1, 2, 3, 5, 7, 10, 15, 20, 25, 35, 40, 50 and 60 days after administration. Recovered plasma was analysed to quantify IVM and NTX by HPLC. Higher IVM plasma concentrations were measured until 20 days post-administration in “low bw” compared to “high bw” animals, where IVM was recovered up to 35 days post-treatment. The IVM absorption process greatly differed between experimental groups. A significantly higher (p < 0.01) C_max (36.7 ± 7.52 ng/ml) value was obtained at a delayed (p < 0.05) T_max (48.0 ± 0.0 h) in light compared to heavy (C_max: 8.0 ± 0.80 ng/ml; at 34.0 h) body weight sheep. IVM elimination half-life and mean residence time were significantly shorter in light compared to heavy (older) sheep. NTX mean plasma concentrations were lower in “low bw” compared to those measured in “high bw” sheep, with elimination phases declining up to 60 d post-administration in both experimental groups. The NTX AUC value in “low bw” (1188.5 ± 122.6 μg day/ml) was significantly lower (p < 0.05) than that obtained in the “high bw” (oldest) animals (1735.0 ± 155.8 μg day/ml). Shorter NTX elimination half-life and mean residence time (p < 0.01) were obtained in the youngest (“low bw”) compared to the oldest (high bw) sheep. The work reported here assessed for the first time the disposition of IVM and NTX after their combinated injection to sheep, demonstrating that animal body weight/development greatly affects the kinetic behaviour of both anthelmintic drugs.