Identification of 19-epi-okadaic Acid,a New Diarrhetic Shellfish Poisoning Toxin,by Liquid Chromatography with Mass Spectrometry Detection

Okadaic acid (1) (OA) and its congeners are mainly responsible for diarrhetic shellfish poisoning (DSP) syndrome. The presence of several OA derivatives have already been confirmed in Prorocentrum and Dinophysis spp. In this paper, we report on the detection and identification of a new DSP toxin, the OA isomer 19-epi-okadaic acid (2) (19-epi-OA), isolated from cultures of Prorocentrum belizeanum, by determining its retention time (RT) and fragmentation pattern using liquid chromatography coupled with mass spectrometry (LC–MS/MS).     

Effects of 25‐hydroxycholecalciferol with two D3 vitamin levels on production and immunity parameters in broiler chickens

This study was performed in Ross 308 chickens aged 1–21 days and aimed to evaluate whether the addition of 25‐hydroxycholecalciferol (25(OH)D₃) to broiler chicken diets affects their growth performance and immunity. A completely random 2 × 2 factorial arrangement was used with two levels of vitamin D₃ and the absence or presence of 25(OH)D₃, corresponding to four treatments based on sorghum + soya bean diets: (i) 200 IU of vitamin D₃/kg of feed (Diet 1) (NRC, 1994 ), (ii) Diet 1 + 69 μg of 25(OH)D₃/kg of feed (Diet 2), (iii) 5,000 IU of vitamin D₃/kg of feed (Diet 3) and (iv) Diet 3 + 69 μg of 25(OH)D₃/kg of feed (Diet 4). Each treatment was conducted with six replicates of 10 chickens each. Water and feed was supplied ad libitum. The results showed significantly increased growth and tibia ash (p < .05) in the birds fed 5,000, IU of vitamin D₃/kg + 25(OH)D₃. Additionally, the cellular immune response increased significantly (p < .05) in both treatments with added 25(OH)D_3. Based on the results obtained under the current test conditions, the addition of 25(OH)D₃ at a rate of 69 μg/kg to diets containing vitamin D₃ improved the cellular immune response and mineral deposition in the bones of broilers aged 1–21 days. Because these parameters are very important in modern poultry farming, these results indicate that supplementation with 25(OH)D₃ should improve broiler production.     

Using State and Transition Models to Determine the Opportunity Cost of Providing Ecosystem Services

A ranch-level model using state-and-transitions models for three ecological sites is used to determine the trade-offs of providing various ecosystem services. The hypothetical ranch is located in northern Colorado and is based upon area average ecological site characteristics and livestock production practices. Management decisions include stocking rate and brush control. The model includes exogenous factors such as precipitation and fire. The model solves for optimal decisions over an infinite planning horizon using stochastic dynamic programming. Results show that a ranch cannot provide all ecosystem services in tandem at their highest level, implying that land managers must decide which ecosystems service they want to provide. Also, it is much cheaper in terms of foregone profitability for a ranch to continue to provide a specific ecosystem service that is already provided by the ranch rather than try to transition the ranch to a new ecological state in order to provide a service currently not provided.     

Spatial analysis of bovine spongiform encephalopathy in Galicia, Spain (2000-2005)

In Spain, the first bovine spongiform encephalopathy (BSE) case was detected in 2000 in a cow born in the Galicia region (Northwestern Spain). From then and until October 2005, 590 cases were detected, 223 of them in Galicia.

In 1994, meat and bone meal (MBM) was banned on ruminant feed and, in 1996, an EU decision mandating an overall change in MBM processing was implemented. This decision was gradually applied in the territory and not enforced before July 1998. The objective of this study was to explore clustering of BSE cases and estimate the standard incidence ratio (SIR) of BSE in Galicia. Our study was based on the BSE cases detected during the surveillance period 2000–2005 in the Galicia region. These cases were divided, based on birth date, into two periods: animals born from 1994 to July 1998, and those born after July 1998. We tested the role of cross-contamination on the geographical SIR distribution for both periods. Hierarchical Bayesian models were used to model the overdispersion and lack of independence of the SIR estimates. The geographical distribution of the standard incidence ratio of BSE between both periods was different. In the second period, the SIR was reduced in some areas. The reduction in these areas could be attributable to the changes in the processing of MBM. We did not find any statistical link between the poultry population and the standard incidence ratio, but pig population had a positive effect.     

Risk factors associated with the prevalence of tuberculosis-like lesions in fenced wild boar and red deer in south central Spain

In recent decades the management of large game mammals has become increasingly intensive in south central Spain (SCS), resulting in complex epidemiological scenarios for disease maintenance, and has probably impeded schemes to eradicate tuberculosis (TB) in domestic livestock. We conducted an analysis of risk factors which investigated associations between the pattern of tuberculosis-like lesions (TBL) in wild boar (Sus scrofa) and red deer (Cervus elaphus) across 19 hunting estates from SCS and an extensive set of variables related to game management, land use and habitat structure. The aggregation of wild boar at artificial watering sites was significantly associated with an increasing risk of detecting TBL in both species, which probably relates to enhanced opportunities for transmission. Aggregation of wild boar at feeding sites was also associated with increased risks of TBL in red deer. Hardwood Quercus spp. forest availability was marginally associated with an increased risk of TB in both species, whereas scrubland cover was associated with a reduced individual risk of TBL in the wild boar. It is concluded that management practices that encourage the aggregation of hosts, and some characteristics of Mediterranean habitats could increase the frequency and probability of both direct and indirect transmission of TB. These findings are of concern for both veterinary and public health authorities, and reveal tuberculosis itself as a potential limiting factor for the development and sustainability of such intensive game management systems in Spanish Mediterranean habitats.     

First report of a Rhipicephalus microplus tick population multi-resistant to acaricides and ivermectin in the Mexican tropics

We document the presence of a Rhipicephalus microplus tick population resistant to acaricides (organophosphates (OP), synthetic pyrethroids (SP), amitraz) and macrocyclic lactones (ML) (ivermectin). Engorged females of R. microplus were collected from a cattle farm in Veracruz, Mexico, to evaluate acaricide and ivermectin resistance. The modified larval packet test (LPT) was used to detect OP (chlorpiriphos and diazinon) and SP (flumethrin, deltamethrin and cypermethrin) resistance and the larval immersion test (LIT) to detect resistance to amitraz and ivermectin. Both, LPT and LIT were performed twice at different times with different collected samples. Mortality data with ivermectin were subjected to probit analysis to obtain lethal concentrations and resistance ratios (RR) using an ivermectin-susceptible strain (Deutch) as a reference. The R. microplus population showed resistance to all acaricides tested, with different mortalities at the discriminate dose: chlorpiriphos (1%), diazinon (24.2%), flumethrin (92.8%), deltamethrin (94.2%), cypermethrin (98.0%) and amitraz (1.5%). The studied tick population also showed resistance to ivermectin with a resistance ratio at 99% of 9.58 and 6.52 in the first and second evaluation, respectively. We report for the first time a R. microplus population in Mexico with different levels of resistance to OP, SP, amidines (Am) and ivermectin. The uncontrolled use of these products in the study area may promote the complete failure of tick control within a short period of time.     

Effect of Different Media and Protein Source on Equine Gametes: Potential Impact During In Vitro Fertilization

Equine in vitro fertilization (IVF) is still inconsistent. In the present work, we studied how modified Whitten's (MW) medium and Tissue Culture Medium 199 (TCM) added with Foetal Bovine Serum (FBS; 10% v/v) or Bovine Serum Albumin (BSA; 7 mg/ml) affected equine gametes to subsequently run IVF trials. Compact (Cp) and expanded (Ex) cumuli equine oocytes were matured and placed in TCM or MW supplemented with BSA or FBS for 18–20 h (no sperm added). In Ex oocytes, TCM‐199 added with FBS or BSA resulted in higher metaphase II (MII) rates (75.7% and 62.7%, respectively) than MW added with BSA (54%) or FBS (52.2%; p < 0.05); this was not observed for Cp oocytes. Equine sperm were capacitated in the same media at 10 × 10⁶ sperm/ml for 4 h at 37°C; total motility and protein tyrosine phosphorylation (PY) were evaluated. While motility remained unchanged, TCM or MW added with FBS enhanced the number of sperm showing PY‐stained tails (25 ± 4.8% and 31 ± 6.6%; mean ± SEM, respectively) over BSA supplemented media (3 ± 1.2% and 11.7 ± 1.1%) for TCM and MW (p < 0.05). In view of the previous results, sperm were capacitated in TCM + FBS and MW + BSA (control); IVF trials were run in the same media supplemented with 200 ng/ml of progesterone, but no fertilization occurred. Our results show that TCM + FBS enhances Ex equine oocyte's meiotic competence over MW + BSA and TCM or MW added with FBS successfully induce equine PY over media supplemented with BSA.     

Hemagglutinating activity of serovar reference strains of Ornithobacterium rhinotracheale.

In the present study, the hemagglutinating activity of 9 reference strains (serovars A-I) of Ornithobacterium rhinotracheale was investigated by using fresh erythrocytes from 15 different species: chicken (broiler, rooster, hen), turkey, pigeon, quail, duck, Harris hawk (Parabuteo unicinctus), house finch (Carpodacus mexicanus), cow, sheep, horse, dog, rabbit, pig, human (groups A, B, AB, and O), and rainbow trout (Oncorhynchus mykiss). All 9 strains agglutinated rabbit erythrocytes. None of the strains was able to agglutinate hen, cow, horse, or rainbow trout erythrocytes. The number of positive reactions among the remaining species varied. Results indicate that the use of rabbit erythrocytes is better suited for testing the hemagglutinating activity of O. rhinotracheale.