Comparison between a live, attenuated anticoccidial vaccine and an anticoccidial ionophore, on performance of broilers raised with or without a growth promoter, in an initially Eimeria-free environment.

An experiment was carried out to study the effects of vaccination with Paracox, a live, attenuated vaccine against avian coccidiosis, on broilers isolated from extraneous Eimeria parasites. The study involved 3200 broiler chickens raised in floor pens similar to commercial conditions, but in an initially Eimeria-free environment. Forty percent of the chickens were vaccinated at 3 days of age and given either a basal unmedicated feed or a feed supplemented with the feed antibiotic virginiamycin. Unvaccinated birds were given either the basal feed or feed supplemented either with virginiamycin or the anticoccidial ionophore narasin. At slaughter at 36 days of age vaccinated birds had a lower live weight than non-vaccinated birds. The difference was 4.6% in unmedicated, and 6.0% in virginiamycin medicated chickens. Feed conversion ratio at slaughter was 2.5% higher for unmedicated vaccinated birds, and 1.3% higher for virginiamycin medicated vaccinated birds, compared to respective non-vaccinated groups. There was no significant difference in overall performance of unvaccinated birds given narasin as compared to virginiamycin. At 10 days post vaccination vaccinated birds had a higher number of Clostridium perfringens in the caeca, but there was no difference thereafter. Throughout the experiment, caecal clostridial counts were considerably higher in vaccinated unmedicated birds than in unvaccinated birds given narasin. The number of oocysts shed in the vaccinated groups was very low, but during a subsequent challenge with E. maxima and E. tenella the birds' immunity was found to be satisfactory.     

Heavy Metal Pollution by Atmospheric Transport in Natural Soils from the Northern Part of Eastern Carpathians

The present paper is a study of the heavy metal contamination ofnatural soils due to atmospheric transport in the northern partof Eastern Carpathians. The study area is located north of BaiaMare, the main Romanian centre for processing complex sulphideores. Ten undisturbed soil profiles of andosols and andic soilswere investigated. The distribution of heavy metals (Pb, Cu, Zn,Mn, Ni, Co, Cr and Cd) was studied along the soil profile and atspecific distances from the pollution sources. In addition tothe total nitric acid soluble fraction of the metals, amounts oflead, copper, zinc and manganese extractable with 0.05 Mhydrochloric acid were determined to evaluate the fraction ofeach metal potentially available to plants. Surface soils in theIgnis Mountains (10 km from Baia Mare) were more polluted withlead (200–800 ppm), with the concentration decreasing withdistance from the processing plants. Lower lead concentrationswere observed in the deeper soil horizons. The fraction of leadextractable in 0.05 M hydrochloric acid was generally higher athigh total concentrations of lead. From its geographical andsoil profile distributions it is also evident that cadmium wasalso supplied in appreciable amounts to the topsoil from thesame polution sources, whereas the trend was weaker for zincand chromium and not evident for copper, manganese, nickel, orcobalt. The fraction extractable with 0.05 M hydrochloric acidgenerally followed the order Pb > Cu > Zn > Mn.     

Swine Dysentery: A Scanning Electron Microscopic Investigation

An investigation by scanning electron microscope was performed on colonic specimens from 4 conventionally reared pigs, 2 of which were suffering from swine dysentery (SD) after inoculation with Treponema hyodysenteriae in pure culture. In pigs with SD dilated cryptal openings surrounded by uneven mucosa with furrows and ridgeformations were found in areas with scattered pseudomembranes. The treponemes were numerous on the mucosal surface but seemed only to penetrate damaged epithelial cells. Freeze-fractured sections from the same pigs revealed dilated crypts where the microvilli were short, irregular and markedly reduced in number possibly due to change in cell kinetics. The present study seems to indicate that epithelial attachment and penetration of treponemes are of minor importance in SD pathogenesis.     

Hypomagnesemia in 188 Dogs: A Hospital Population-Based Prevalence Study

Magnesium is a divalent cation involved in more than 300 metabolic processes. Magnesium acts as an intracellular regulator of most energy-demanding pathways. Clinical investigation in the human medical field has determined risk factors for hypomagnesemia and its relationship to a number of disease processes. Experimental studies have established the effects of hypomagnesemia in dogs, but little is known of its prevalence, risk factors, or clinical associations in a hospital population of dogs. To study the prevalence, risk factors, and clinical associations of hypomagnesemia in dogs, a retrospective cross-sectional study of dogs admitted to the University of Minnesota Veterinary Teaching Hospital over a 2.5-year period was undertaken. The prevalence of hypomagnesemia in the study population was 6.1% (188 of 3,102 dogs). Using both categorical and continuous variables in a univariate analysis, significant associations with hypomagnesemia were identified and used to construct a multivariate analysis of the relative risk of hypomagnesemia. Results from evaluation of 3,102 dogs indicate that the most significant predictors of hypomagnesemia were albumin ( P ≤ .0001; odds ratio [OR] = 0.2), potassium ( P ≤ .0001; OR = 0.5), total CO₂ ( P ≤.05; OR = 0.9), and blood urea nitrogen concentrations ( P < .0001; OR = 0.9), a diagnosis of cardiovascular disease ( P < .02; OR = 1.9); and being a Collie ( P < .02; OR = 3.9) or German Shepherd Dog ( P < .002; OR = 2.2). These results can be used to better understand and predict hypomagnesemia in dogs.     

Evaluation of a new management scheme for Norwegian Atlantic salmon Salmo salar

Atlantic salmon, Salmo salar L., stocks are decreasing worldwide, and major efforts are underway to conserve populations that are threatened. In a recent effort to conserve the Norwegian salmon, the Norwegian government implemented in 2007 a scheme called National Atlantic Salmon Watercourses and Fjords (NASW), where 52 rivers were given special protection. Here, the scheme is described and it is evaluated if and to what extent the scheme has led to changes in management practice. After the implementation of the NASW scheme, fewer plans for development (e.g. hydropower plants, water abstraction, flood and erosion control) at the within‐river level were accepted for NASW‐rivers than for rivers not in the scheme. However, at the same time, there was a tendency for fewer plans overall being sanctioned in all types of rivers probably due to overall changes in management practices not related to the NASW scheme. In total, these changes could lead to increased protection of Norwegian Atlantic salmon populations.     

vapA (A‐layer) typing differentiates Aeromonas salmonicida subspecies and identifies a number of previously undescribed subtypes

Sequence variation in a region of the virulence array protein gene (vapA; A‐layer) was assessed in 333 (‘typical’ and ‘atypical’) isolates of the fish pathogenic bacterium Aeromonas salmonicida. Resulting similarity dendrograms revealed extensive heterogeneity, with nearly all isolates belonging to either of 14 distinct clusters or A‐layer types. All acknowledged A. salmonicida subspecies (except ssp. pectinolytica, from which no vapA sequence could be obtained) were clearly separated, and notably, all isolates phenotypically identified as ssp. salmonicida formed a distinct and exclusive A‐layer type. Additionally, an array of un‐subspeciated atypical strains formed several equally prominent clusters, demonstrating that the concept of typical/atypical A. salmonicida is inappropriate for describing the high degree of diversity evidently occurring outside ssp. salmonicida. Most representatives assessed in this study were clinical isolates of spatiotemporally diverse origins, and were derived from a variety of hosts. We observed that from several fish species or families, isolates predominantly belonged to certain A‐layer types, possibly indicating a need for host‐/A‐layer type‐specific A. salmonicida vaccines. All in all, A‐layer typing shows promise as an inexpensive and rapid means of unambiguously distinguishing clinically relevant A. salmonicida subspecies, as well as presently un‐subspeciated atypical strains.     

Comparing methods for handling missing values in food-frequency questionnaires and proposing k nearest neighbours imputation: effects on dietary intake in the Norwegian Women and Cancer study (NOWAC)

OBJECTIVE: To investigate item non-response in a postal food-frequency questionnaire (FFQ), and to assess the effect of substituting/imputing missing values on dietary intake levels in the Norwegian Women and Cancer study (NOWAC). We have adapted and probably for the first time applied k nearest neighbours (KNN) imputation to FFQ data. DESIGN: Data from a recent reproducibility study were used. The FFQ was mailed twice (test-retest) about 3 months apart to the same subjects. Missing responses in the test FFQ were imputed using the null value (frequencies = null, amount = smallest), the sample mode, the sample median, KNN, and retest values. SETTING: A methodological substudy of NOWAC, a national population-based cohort. SUBJECTS: A random sample of 2000 women aged 46-75 years was drawn from the cohort in 2002 (response 75%). The imputation methods were compared for 1430 women who completed at least 50% of the test FFQ. RESULTS: We imputed 16% missing values in the overall test data matrix. Compared to null value imputation, the largest differences in estimated dietary intake were seen for KNN, and for food items with a high proportion of missing. Imputation with retest values increased total energy intake, indicating that not all missing values are caused by respondents failing to specify no consumption, and that null value imputation may lead to underestimation and misclassification. CONCLUSION: Missing values in FFQs present a methodological challenge. We encourage the application and evaluation of newer imputation methods, including KNN, which may reduce imputation errors and give more accurate intake estimates.     

Use of folic acid supplements, particularly by low-income and young women: a series of systematic reviews to inform public health policy in the UK

OBJECTIVE: To provide a basis for making recommendations on the potential to improve use of folic acid supplements in the UK, particularly among low-income and young women. DESIGN: Systematic reviews of relevant research from 1989 to May 2006 in Europe, the USA, Canada, Australia and New Zealand. RESULTS: Twenty-six systematic reviews and/or meta-analyses were identified from the wider public health literature, and eighteen studies on the effectiveness of preconception interventions were included. Ninety studies were identified which were directly relevant to folic acid supplement intake. There were factors that are particularly associated with lower rates of use of folic acid supplements. One of the most important of these is the link with unintended pregnancy, followed by age, socio-economic and ethnic group. Integrated campaigns can increase the use of folic acid supplements to some extent. Research trials indicated that: (i) printed resources and the mass media used in isolation are not effective in the longer term; and (ii) health-care-based initiatives can be effective and are more likely to be successful if they include making supplements easily available. CONCLUSIONS: Campaigns and interventions have the potential to exacerbate socio-economic inequalities in folic acid use. One way of addressing this is to include elements that specifically target vulnerable women. To achieve and maintain an effect, they need to be based on good health promotion practice and to be sustained over a long period. However, even high-quality campaigns that increase use result in under half of women in the target group taking supplements.     

Comparison between genomic predictions using daughter yield deviation and conventional estimated breeding value as response variables

This study compared genomic predictions using conventional estimated breeding values (EBV) and daughter yield deviations (DYD) as response variables based on simulated data. Eight scenarios were simulated in regard to heritability (0.05 and 0.30), number of daughters per sire (30, 100, and unequal numbers with an average of 100 per sire) and numbers of genotyped sires (all or half of sires were genotyped). The simulated genome had a length of 1200 cM with 15,000 equally spaced Single-nucleotide polymorphism (SNP) markers and 500 randomly distributed Quantitative trait locus (QTL). In the simulated scenarios, the EBV approach was as effective as or slightly better than the DYD approach at predicting breeding value, dependent on simulated scenarios and statistical models. Applying a Bayesian common prior model (the same prior distribution of marker effect variance) and a linear mixed model (GBLUP), the EBV and DYD approaches provided similar genomic estimated breeding value (GEBV) reliabilities, except for scenarios with unequal numbers of daughters and half of sires without genotype, for which the EBV approach was superior to the DYD approach (by 1.2 and 2.4%). Using a Bayesian mixture prior model (mixture prior distribution of marker effect variance), the EBV approach resulted in slightly higher reliabilities of GEBV than the DYD approach (by 0.3-3.6% with an average of 1.9%), and more obvious in scenarios with low heritability, small or unequal numbers of daughters, and half of sires without genotype. Moreover, the results showed that the correlation between GEBV and conventional parent average (PA) was lower (corresponding to a relatively larger gain by including PA) when using the DYD approach than when using the EBV approach. Consequently, the two approaches led to similar reliability of an index combining GEBV and PA in most scenarios. These results indicate that EBV can be used as an alternative response variable for genomic prediction.