Morphofunctional diversity of equine of varied genetic compositions raised in the Pantanal biome of Brazil

Evaluating phenotypic diversity makes it possible to identify discrepancies in aptitudes among animals of different genetic bases, which is an indicator of adaptive or selective differences between populations. The objective of this work was to evaluate the morphofunctional diversity of 452 male and female adult equines (Arabian, Quarter Mile, Pantaneiro, and Criollo breeds, and undefined crossbreeds of horses and mules) raised in the Pantanal biome (Brazil). Linear measurements were performed to estimate conformation indexes. Initially, a discriminant analysis was performed, regardless of the animal’s size, followed by factor analysis. The factors were characterized and used as new variables. The diversity among equines and their relationship with the factors were evaluated using multivariate analysis. The factors were classified according to their decreasing importance: balance, rusticity, and robustness for the measurement factors; and load, ability, conformation, and equilibrium for the index factors. The genetic groups of equines have well-defined morphofunctional characteristics. The main differences are based on the rusticity and ability typologies in relation to those based on performance. Equines introduced to the Pantanal biome presented a more robust and compact body with good conformation. As a result, these horses may have superior athletic performance during equestrian activities when compared to the Pantaneiro local breed. However, this biotype may represent less rusticity (less adaptive capacity). Therefore, the regional breed can be equal or better in equestrian activities than breeds introduced to the Pantanal biome. Thus, breeders may cross horses from local breeds as an alternative to those introduced. Undefined crossbred male equines presented a different profile from the Pantaneiro breed, which may indicate little use of crossbreeds in breeding.     

Disposition of levetiracetam in healthy adult horses

Nine horses received 20 mg/kg of intravenous (LEV_IV ); 30 mg/kg of intragastric, crushed immediate release (LEV_CIR ); and 30 mg/kg of intragastric, crushed extended release (LEV_CER ) levetiracetam, in a three‐way randomized crossover design. Crushed tablets were dissolved in water and administered by nasogastric tube. Serum samples were collected over 48 hr, and levetiracetam concentrations were determined by immunoassay. Mean ± SD peak concentrations for LEV_CIR and LEV_CER were 50.72 ± 10.60 and 53.58 ± 15.94 μg/ml, respectively. The y ‐intercept for IV administration was 64.54 ± 24.99 μg/ml. The terminal half‐life was 6.38 ± 1.97, 7.07 ± 1.93 and 6.22 ± 1.35 hr for LEV_CIR , LEV_{CER ,} and LEV_IV , respectively. Volume of distribution at steady‐state was 630 ± 73.4 ml/kg. Total body clearance after IV administration was 74.40 ± 19.20 ml kg^?1 hr^?1. Bioavailability was 96 ± 10, and 98 ± 13% for LEV_CIR and LEV_CER , respectively. A single dose of Levetiracetam (LEV ) was well tolerated. Based on this study, a recommended dosing regimen of intravenous or oral LEV of 32 mg/kg every 12 hr is likely to achieve and maintain plasma concentrations within the therapeutic range suggested for humans, with optimal kinetics throughout the dosing interval in healthy adult horses. Repeated dosing and pharmacodynamic studies are warranted.     

Relationship between DNA fragmentation of equine granulosa cells and oocyte meiotic competence after in vitro maturation

The acquisition of equine oocyte developmental capacity is ensured by the follicular environment, such as granulosa cells, which could reflect the meiotic development potential of immature oocytes. This study evaluated the relationship between DNA fragmentation of granulosa cells, using the chromatin dispersion test, and equine oocyte meiotic development after in vitro maturation. Granulosa cells and cumulus–oocytes complexes (n = 50) were recovered from slaughterhouse‐derived ovaries. Oocytes were in vitro matured, stained and evaluated under fluorescence microscopy. Maturation rates were classified into outstanding, medium and poor levels of maturation using 25th and 75th percentiles as thresholds. For DNA assessment, each sample was processed with the Ovoselect^® kit (Halotech DNA). High, low and total DNA fragmentation percentages were compared among levels of maturation rates by ANOVA, followed by Duncan test. Results were expressed as mean ± SE. Total and high DNA fragmentation rates of granulosa cells were significantly higher (p < 0.05) in follicles whose oocytes had reached outstanding maturation level than those originating from follicles whose oocytes had reached poor maturation level. In conclusion, the DNA fragmentation analysis of equine granulosa cells can be a valuable test to identify equine oocytes showing the best meiotic competence after in vitro maturation.     

Control of cystic echinococcosis: Background and prospects

Cystic echinococcosis (CE), caused by Echinococcus granulosus, is a chronic and debilitating zoonotic larval cestode infection in humans, which is principally transmitted between dogs and domestic livestock, particularly sheep. Human CE occurs in almost all pastoral communities and rangeland areas of the underdeveloped and developed world. Control programmes against CE have been implemented in several endemic countries to reduce or eliminate the disease. New Zealand and Tasmania are examples of some of the first programmes to be undertaken (in insular territories) and which were very successful in the elimination of CE. The advent and proven effectiveness of praziquantel, plus the experience of insular models, produced high expectations for rapid advances in a second generation of control programmes undertaken in continental areas (Argentina, Uruguay and Chile). Nevertheless, only moderate gains in CE control have been made and the impact on prevalence among humans has been slight. A major impediment to the adoption of procedures that were successful in New Zealand and Tasmania has been the requirement to administer praziquantel to dogs in rural areas eight times per year over numerous years. In addition, there have been clear technological improvements made in the diagnosis of canine echinococcosis for surveillance, the genetic characterization of parasite strains and in vaccination against CE infection in livestock. In order to establish new paradigms and appropriate combinations of control strategies, we have carried out a review and discussion of the available control tools and control models. Control strategies must be suitable and sustainable to benefit the Echinococcosis–endemic areas primarily, which at the same time are the poorest regions of the world.     

Spray‐dried porcine plasma improves feed intake of weaned piglets subjected to heat stress

The objective of this study was to evaluate the effects of spray‐dried porcine plasma (SDPP) on performance, measurement of thyroid hormones triiodothyronine (T3) and thyroxine (T4), body temperature and relative organ weights of weaned piglets exposed to a heat stress or a thermoneutral environment. One hundred and forty‐four piglets with initial BW of 5.82 ± 0.33 kg (28 d old) were used. The experimental design was a 4 x 2 factorial arrangement, four plasma levels (0.0, 2.5, 5.0 and 7.5%) and two environments (34º [heat stress (HS)] and 24°C [thermoneutral (TN)]). SDPP was fed from weaning (28 d of age) to the end of the trial (piglets were weighed at the beginning, 7, 21 and 35 days of trial). Rectal, neck, shoulder and leg temperatures were measured every seven days. At 21 days of trial, one piglet per pen was slaughtered to determine the weight of the carcass and organs. Blood samples were collected at 18 and 35 days of trial to determine levels T3 and T4. The rectal, neck, shoulder and leg temperatures were increased (p < 0.05) 0.4, 1.5, 1.0 and 1.3ºC, respectively, and relative weight of the lungs (p < 0.05) and total T3 (p < 0.05) were decreased 0.001 kg/kg and 0.19 ng/dl, respectively, for pigs in the HS environment. The estimated inclusion of 5.1% of SDPP had the greatest (p < 0.05) weight gain during the first week, and throughout the nursery phase, the 5% of inclusion had a tendency of improvement (p = 0.075), regardless of ambient temperature. For the entire period, pigs reared in the HS environment had the greatest (p < 0.05) estimated feed intake by the quadratic regression with the inclusion of 4.3% of SDPP.     

Dynamics of carbon and nitrogen in an extreme alkaline saline soil: A review

The soil of the former lake Texcoco is an ‘extreme’ alkaline saline soil with pH > 10 and electrolytic conductivity (EC) > 150 dS m⁻¹. These conditions have created a unique environment. Application of wastewater sludge to Texcoco soil showed that large amounts of NH₄⁺ were immobilized, NO₃⁻ was reduced aerobically, NO₂⁻ was formed and the mineralization of the organic material in the sludge was inhibited. A series of experiments were initiated to study the processes that inhibited the decomposition of organic material and affected the dynamics of mineral N. The large EC and pH inhibited the decomposition of easily decomposable organic material such as glucose and maize, although cellulolytic activity was observed in soil with pH 9.8 and EC 32.7 dS m⁻¹. The high soil pH favoured NH₃ volatilization of approximately 50 mg N kg⁻¹ soil within a day and a similar amount could be fixed on the soil matrix due to the dispersed minerals and their volcanic origin. Soil microorganisms immobilized large amounts of NH₄⁺ within a day when glucose was added to soil in excess of what was required for metabolic activity. Removal of NO₃⁻ from soil amended with glucose was not inhibited by 100% O₂ and NH₄⁺ indicating that the contribution of denitrification and assimilatory reduction to the reduction of NO₃⁻ was minimal while the formation of NO₂⁻ was not inhibited by 0.1% acetylene, known to inhibit nitrification. Additionally, the reduction of NO₃⁻ in the glucose-amended alkaline saline Texcoco soil was followed by an increase in the amount of NH₄⁺, which could not be due to denitrification. It was concluded that the reduction of NO₃⁻ and the formation of NO₂⁻ and NH₄⁺ in the glucose-amended soil was a result of aerobic NO₃⁻ reduction. A phylogenetic analysis of the archaeal community in the soil of the former lake Texcoco showed that some of the clones identified were capable of reducing NO₃⁻ aerobically to NO₂⁻ when glucose was added. A study of the diversity of the bacterial dissimilatory and respiratory nitrate-reducing communities indicated that bacteria could have contributed to the process.     

Inheritance of resistance to Acanthoscelides obtectus in a wild common bean accession crossed to commercial bean cultivars

Summary The bean weevil Acanthoscelides obtectus, is an important storage pest of common beans in Latin America and Africa. A few wild bean accessions from Mexico have been identified as highly resistant to the weevil. One accession, G 12952, was crossed to two susceptible bean cultivars differing in seed size. Reciprocal F1 and F2 individual seed were evaluated for days to adult emergence (DAE) and emerged adult weight. Maternally inherited seed size affected resistance measurements only in the F1 reciprocal crosses, however, the overall resistance level of the F1 was more similar to that of the susceptible cultivars. The F2 showed a continuous, but skewed distribution from low to high DAE. Very few F2 individuals had the resistance level of G 12952. When the frequency distributions were divided into discrete categories based on parental response, resistance was found to be inherited as two recessive complementary genes. The F3 generation showed an overall lowering of resistance levels compared to their original F2 evaluations. However, none of the lines classified as resistant (50 DAE) in the F2, fell into the susceptible category in the F3, indicating that the resistant genotypes were relatively stable as expected with recessively inherited traits. Modifying genes from the commercial parents may be responsible for general lowering of resistance. Seed size was negatively correlated with adult weight but not with DAE. The unique resistance of the wild bean accessions is discussed in relation to its inheritance. The results and obstacles encountered in the A. obtectus breeding program at CIAT are described.