Rough vaccines in animal brucellosis: structural and genetic basis and present status

Brucellosis control and eradication requires serological tests and vaccines. Effective classical vaccines (S19 in cattle and Rev 1 in small ruminants), however, induce antibodies to the O-polysaccharide of the lipopolysaccharide which may be difficult to distinguish from those resulting from infection and may thus complicate diagnosis. Rough attenuated mutants lack the O-polysaccharide and would solve this problem if eliciting protective immunity; the empirically obtained rough mutants 45/20 and RB51 have been used as vaccines. Strain 45/20 is reportedly unstable and it is not presently used. RB51 is increasingly used instead of S19 in some countries but it is rifampicin resistant and its effectiveness is controversial. Some controlled experiments have found good or absolute protection in adult cattle vaccinated orally (full dose) or subcutaneously (reduced dose) and in one field experiment, RB51 was reported to afford absolute protection to calves and to perform better than S19. Controlled experiments in calves, however, have shown reduced doses of RB51 to be ineffective, full doses only partially effective, and RB51 less effective than S19 against severe challenges. Moreover, other observations suggest that RB51 is ineffective when prevalence is high. RB51 is not useful in sheep and evidence in goats is preliminary and contradictory. Rough mutants obtained by molecular biology methods on the knowledge of the genetics and structure of Brucella lipopolysaccharide may offer alternatives. The B. abortus manBcore (rfbK) mutant seems promising in cattle, and analyses in mice suggest that mutations affecting only the O-polysaccharide result in better vaccines than those affecting both core and O-polysaccharide. Possible uses of rough vaccines also include boosting immunity by revaccination but solid evidence on its effectiveness, safety and practicality is not available.     

Seroprevalence and risk factors for Neospora caninum in sheep in the state Minas Gerais, southeastern Brazil

The aim of this study was to determine the prevalence and risk factors associated with infection due to Neospora caninum in serum samples from 488 sheep originating from 63 farms in 63 municipalities distributed across eight of the twelve mesoregions of the state Minas Gerais, southeastern Brazil. For detection of N. caninum the sheep serum samples were subjected to the indirect fluorescence antibody test (IFAT ≥ 50). To identify the risk factors associated with infection due to N. caninum a questionnaire was filled out for each herd by interviewing, the individual responsible for the herd, demanding information on the general characteristics of the property. Sixty-four sheep sera (13.1%; 95% CI=10.3-16.4) presented IgG-specific anti-N. caninum antibodies with the following titers: 50 (49; 76.6%), 100 (7; 10.9%), 200 (4; 6.2%), 400 (3; 4.7%) and 800 (1; 1.6%). The prevalence of infected sheep per mesoregion ranged from 0 to 28.1%. Out of the 63 farms sampled, 31 (49.2%; 95% CI=36.4-62.1) presented at least one seropositive sheep. No significant association was found between the presence of anti-N. caninum antibodies and the risk factors evaluated on the farms, except for the mesoregion variable (p=0.004; OR=0.429; CI95%=0.182-1.008). These results indicate that there is a need for additional research to define the epidemiological importance of this parasite as a cause of reproductive problems in sheep herds in Minas Gerais.     

SALTIRSOIL: a simulation model for the mid to long‐term prediction of soil salinity in irrigated agriculture

The SALTIRSOIL model predicts soil salinity, sodicity and alkalinity in irrigated land using basic information on soil, climate, crop, irrigation management and water quality. It extends the concept of the WATSUIT model to include irrigation and crop management practices, advances in the calculation of evapotranspiration and new algorithms for the water stress coefficient and calculation of electrical conductivity. SALTIRSOIL calculates the soil water balance and soil solution concentration over the year. A second module, SALSOLCHEM, calculates the inorganic ion composition of the soil solution at equilibrium with soil calcite and gypsum at the soil’s CO₂ partial pressure. Results from comparing predicted and experimentally determined concentrations, observations and predictions of pH, alkalinity and calcium concentration in calcite‐saturated solutions agree to the second significant figure; in gypsum‐saturated solutions the standard difference between observations and predictions is <3% in absolute values. The algorithms in SALTIRSOIL have been verified and SALSOLCHEM validated for the reliable calculation of soil salinity, sodicity and alkalinity at water saturation in well‐drained irrigated lands. In simulations for horticultural crops in southeast Spain, soil solution concentration factors at water saturation, quotients of electrical conductivity (EC₂₅) at saturation to electrical conductivity in the irrigation water, and quotients of sodium adsorption ratio (SAR) are very similar to average measured values for the area.     

Swine viscera preservation in hypersaturated salt solution after alcohol fixation as a preparation method for educational purposes

The use of live animals for educational purposes is an old practice that is still employed in teaching and research institutions. However, there are several objections to this practice, whether for ethical or humanitarian reasons. Surgical techniques teaching using anatomical pieces and/or preserved cadavers promotes greater learning efficiency, provides exercise repetition and increases the confidence and satisfaction of the students when compared to the use of live animals. The current work aimed to analyse the feasibility of using fresh swine urinary bladder and small intestines (jejunum), obtained from slaughterhouses, fixed in 99.8% ethyl alcohol (EA) and preserved in sodium chloride hypersaturated solution (SCHS) at 30%, for 7, 14 and 21 days, as an alternative method for surgical skills training (SST). Swine viscera, fixed in EA and preserved in SCHS, presented a realistic appearance, absence of odour and maintained the viable morphological characteristics during the performance of the operative techniques. Preservation solutions had low cost, were easy to acquire and did not offers risks to human health. Therefore, urinary bladders and small intestines fixed in 99.8% EA for 30 days and maintained in 30% SCHS at different periods were demonstrated as a good viable option as a preservation method for surgical skills training.     

Effect of the Nixtamalization Process on the Dietary Fiber Content,Starch Digestibility,and Antioxidant Capacity of Blue Maize Tortilla

Nixtamalization is an ancient process developed by the Mesoamerican cultures. Initially, volcanic ashes were used and then calcium hydroxide in commercial production, and more recently nixtamalization with calcium salts (NCS) has been proposed. The aim of this study was to evaluate the effect of NCS on carbohydrate digestibility and antioxidant capacity in the elaboration of blue maize tortillas. NCS in blue tortillas showed a high amount of total dietary fiber (14.27 g/100 g), the main fraction being insoluble dietary fiber. The contents of resistant starch and slowly digestible starch did not change with the nixtamalization process. The predicted glycemic index value was lower in blue tortillas with the NCS process (58) than with the traditional nixtamalization process (71). In general, NCS in blue tortillas presented a higher antioxidant capacity than traditional tortillas (ferric reducing antioxidant power method), indicating that phenolics present in blue maize maintain their activity after cooking. It can be concluded that the nutraceutical features (high dietary fiber content and antioxidant capacity) of blue maize tortillas are enhanced when they are elaborated with the NCS process.     

Genomic prediction for meat and carcass traits in Nellore cattle using a Markov blanket algorithm

This study was carried out to evaluate the advantage of preselecting SNP markers using Markov blanket algorithm regarding the accuracy of genomic prediction for carcass and meat quality traits in Nellore cattle. This study considered 3675, 3680, 3660 and 524 records of rib eye area (REA), back fat thickness (BF), rump fat (RF), and Warner–Bratzler shear force (WBSF), respectively, from the Nellore Brazil Breeding Program. The animals have been genotyped using low-density SNP panel (30 k), and subsequently imputed for arrays with 777 k SNPs. Four Bayesian specifications of genomic regression models, namely Bayes A, Bayes B, Bayes Cπ and Bayesian Ridge Regression methods were compared in terms of prediction accuracy using a five folds cross-validation. Prediction accuracy for REA, BF and RF was all similar using the Bayesian Alphabet models, ranging from 0.75 to 0.95. For WBSF, the predictive ability was higher using Bayes B (0.47) than other methods (0.39 to 0.42). Although the prediction accuracies using Markov blanket of SNP markers were lower than those using all SNPs, for WBSF the relative gain was lower than 13%. With a subset of informative SNPs markers, identified using Markov blanket, probably, is possible to capture a large proportion of the genetic variance for WBSF. The development of low-density and customized arrays using Markov blanket might be cost-effective to perform a genomic selection for this trait, increasing the number of evaluated animals, improving the management decisions based on genomic information and applying genomic selection on a large scale.     

Comparison of Chemical Composition and Biological Properties of Essential Oils Obtained by Hydrodistillation and Steam Distillation of Laurus nobilis L.

Plant Foods for Human Nutrition - The purpose of this study was to compare the yield, chemical composition, antimicrobial and antioxidant properties of essential oils isolated from leaves of Laurus...