Ultrasound evaluation of digital flexor tendons of jumping horses undergoing treadmill training.

This study aimed to perform ultrasonographic evaluation of the digital flexor tendons of jumping horses undergoing complementary training on a treadmill. Fifteen Brazilian Sport horses were divided into two groups: Group I with 7 animals in physical training complementary to the standard training at the Brazilian Army's Riding School; and Group II with 8 animals in standard training used in the Brazilian Army's Riding School. Complementary training was performed on a treadmill on an inclined plane. Ultrasonographic images were taken at the beginning and at the end of training. The left thoracic and pelvic limbs of horses were evaluated for echogenicity values and cross-sectional areas of the superficial digital flexor tendons (SDFTs) and deep digital flexor tendons (DDFTs) in zones IA, IIB, and IIIB. The mean areas of the SDFT were 93.7 mm2 and 95.8 mm2 at the beginning and the end of training, respectively. The cross-sectional area of DDFT increased from 124.6 mm2 at the beginning of training to 136.8 mm2 at the end of training. The echogenicity values of both tendons were between 0 and 1 as expected, concluding that clinically, the animals showed adaptation to the exercise protocol with no signs of tendon injury being detected, implying that traditional training and complementary training are safe.

Esta pesquisa teve como objetivo proceder avaliações ultrassonográficas dos tendões flexores digitais de equinos em treinamento complementar em esteira ergométrica. Foram utilizados 15 equinos da raça Brasileiros de Hipismo (BH), divididos em dois grupos: Grupo I, com sete animais em treinamento físico complementar ao treinamento padrão da Escola de Equitação do Exército; Grupo II, com oito animais em treinamento padrão utilizados na Escola de Equitação do Exército. O treinamento complementar foi executado na esteira ergométrica, em plano inclinado. As imagens ultrassonográficas foram realizadas no início e no final do treinamento. Foram avaliados os membros locomotores torácico e pélvico esquerdos dos equinos quanto a ecogenicidade e a área da seção transversal dos tendões flexores digitais superficiais (TFDS) e tendões flexores digitais profundos (TFDP), nas zonas IA, IIB e IIIB. A média da área dos TFDS foi de 93,7 mm2 e de 95,8 mm2, no início e no final do treinamento, respectivamente. O DDFT apresentou um aumento da área da seção transversa, de 124,6 mm2 no início do treinamento e, de 136,8 mm2 no final do treinamento. A ecogenicidade de ambos os tendões se apresentou entre 0 e 1, como esperado, concluindo-se que clinicamente os animais apresentaram adaptação ao exercício atribuído, não sendo detectados sinais de lesões tendíneas, qualificando o treinamento tradicional e o treinamento complementar como seguros.

Equine parvovirus-hepatitis is detected in South America, Brazil.

The equine parvovirus-hepatitis (EqPV-H), recently identified in association with serum hepatitis in horses (also known as Theiler's disease), has been so far described in horses from North America, Asia and Europe. There is no information regarding its circulation in South America. Our retrospective study (2013-2016) screened by EqPV-H nested-PCR a total of 96 Brazilian horses grouped according to previous status of infection: Known to be positive for one or more horse "hepatitis viruses" (equine hepacivirus, equine pegivirus-EPgV and Theiler's disease-associated virus) and known to be negative. Serum biochemical parameters (aspartate aminotransferase, gamma-glutamyl transferase and glutamate dehydrogenase) were evaluated in EqPV-H positive horses. Molecular characteristics of the isolates were analyzed by DNA sequencing and phylogenetic analysis. EqPV-H DNA was detected in 12.5% (12/96) of horses from 46.6% (7/15) of the farms evaluated. Similar results were obtained between coinfected group (12.3%, 7/57) and non-coinfected group (12.8%, 5/39). Coinfection with EPgV was the most frequent (5/7). Altered serum biochemical parameters suggested a subclinical hepatopathy in some animals (3/12), but the majority presented no clinical or laboratory signs of infection. Nucleotide identity was higher than 94% in comparison with previous isolates. In conclusion, we demonstrated, for the first time in South America, the circulation of EqPV-H. The Brazilian isolates presented a low genetic variability, thus corroborating previous evidence.

Fecal Microbiome Responses to Sudden Diet Change in Mangalarga Marchador horses.

Sudden changes in horses' diet have been previously associated with gastrointestinal disease. This study evaluated the effects of a sudden change of diet composed exclusively of Coastcross hay (CHD) to a complete extruded diet (CED) on the fecal microbiome of horses. A completely randomized design with repeated measurements was used. The study started with eight adult horses randomly split into group A, fed with CHD, and group B, fed with CED. After 34 days of diet adaptation, the diets were abruptly changed between the groups. Fecal samples were collected at 0, 24, and 96 hours after the diet change, and the pH and microbiome analyses of the feces were subsequently evaluated. Changing from CHD to CED reduced the alpha diversity 24 hours after the alteration, with a decrease in the relative abundance of Firmicutes and an increase of Bacteroidetes. Fecal pH decreased and the relative abundance of Verrucomicrobia increased 96 hours after changing the diets. The community structure was also different after 96 hours of diet change. In contrast, 24 hours after changing from CED to CHD reduced fecal pH and abundance of Synergistetes. After 96 hours, there was an increase in the alpha diversity, and the abundance of the phylum Lentisphaerae. Group B showed no changes in the community structure when its diet was changed. Concluding, diet composition influenced the response of the equine fecal microbiome to sudden dietary changes.

First description of Theiler's disease-associated virus infection and epidemiological investigation of equine pegivirus and equine hepacivirus coinfection in Brazil.

Recent advances in the study of equine pegivirus (EPgV), Theiler's disease-associated virus (TDAV) and equine hepacivirus (EqHV) highlight their importance to veterinary and human health. To gain some insight into virus distribution, possible risk factors, presence of liver damage and genetic variability of these viruses in Brazil, we performed a cross-sectional study of EPgV and TDAV infections using a simultaneous detection assay, and assessed EqHV coinfection in different horse cohorts. Of the 500 serum samples screened, TDAV, EPgV and EPgV-EqHV were present in 1.6%, 14.2% and 18.3%, respectively. EPgV-positive horses were present in four Brazilian states: Espírito Santo, Mato Grosso do Sul, Minas Gerais and Rio de Janeiro. Serum biochemical alterations were present in 40.4% of EPgV-infected horses, two of them presenting current liver injury. Chance of infection was 2.7 times higher in horses ≤5 years old (p = 0.0008) and 4.9 times higher in horses raised under intensive production systems (p = 0.0009). EPgV-EqHV coinfection was 75% less likely in horses older than 5 years comparatively to those with ≤5 years old (p = 0.047). TDAV-positive animals were detected in different horse categories without biochemical alteration. Nucleotide sequences were highly conserved among isolates from this study and previous field and commercial product isolates (≥88% identity). Tree topology revealed the formation of two clades (pp = 1) for both EPgV and TDAV NS3 partial sequences. In conclusion, the widespread presence of EPgV-RNA suggests an enzootic infection with subclinical viremia in Brazil. Horse management can influence virus spread. This first report of TDAV-infected horses outside the USA reveals the existence of subclinical viremic horses in distant geographical regions. EPgV and TDAV have similar circulating isolates worldwide. These findings contribute to global efforts to understand the epidemiology and pathogenesis of these equine viruses.

ACTN3 gene variants as potential phenotype and performance biomarkers in Brazilian sport horses training for eventing in a tropical climate.

The aim of this study was to look for mutations in the equine ACTN3 gene and to identify sequence variants that might be associated with the phenotype and performance of Brazilian sport horses training for events in a tropical climate. Among 17 such horses direct DNA sequencing and mutation analysis of the exon 15 and the intron-exon boundaries of ACTN3 revealed 2 new sequence variants in the ACTN3 intron 14-15, designated c.1681-86G > A and c.1681-129delA. Wild-type/deletion heterozygotes (A/del) had a lower mean subcutaneous fat layer in the region of the gluteus medius, as measured by ultrasonography, than the del/del homozygotes; the correlation was significant (P = 0.017). This single base-pair deletion in ACTN3 intron 14-15 may have resulted in metabolic changes that led to increased deposition of body fat in the homozygous state. However, neither sequence variant was correlated with the time to fatigue in a test on a high-speed treadmill with an incremental-speed protocol.

Le but de la présente étude était de vérifier pour la présence de mutations dans le gène ACTN3 équin et d'identifier des variants de séquence qui pourraient être associés avec le phénotype et la performance de chevaux de sport brésiliens qui s'entraînent pour des concours dans un climat tropical. Parmi 17 chevaux qui correspondent à ces critères, le séquençage direct de l'ADN et l'analyse de mutation de l'exon 15 et des frontières de l'intron-exon d'ACTN3 a révélé deux nouveaux variants de séquence dans l'intron 14­15 d'ACTN3, désigné c.1681­86G > A et c.1681­129delA. Chez les hétérozygotes type-sauvage/délétion (A/del) la moyenne de l'épaisseur de la couche de gras sous-cutané dans la région du gluteus medius était plus petite, telle que mesurée par échographie, que celle des homozygotes del/del; la corrélation était significative (P = 0,017). Cette délétion unique de paire de bases dans l'intron 14­15 d'ACTN3 pourrait avoir résulté dans des changements métaboliques qui auraient mené à une augmentation du dépôt de gras chez les homozygotes. Toutefois, aucun des variants de séquence n'était corrélé avec le temps de fatigue dans un test sur un tapis-roulant à haute vitesse avec un protocole d'augmentation de vitesse.(Traduit par Docteur Serge Messier).

Identification of two phylogenetic lineages of equine hepacivirus and high prevalence in Brazil.

Non-primate hepacivirus (NPHV), as described in horses, is the virus most genetically related to hepatitis C virus (HCV). Although detected worldwide, limited data on genomic variability and distribution of NPHV are available in Latin America. The aim of this study was to investigate the genetic diversity and prevalence of equine NPHV in Brazil. Thirteen percent of 202 equines from three Brazilian states were positive for NPHV genome by reverse transcriptase PCR. Nucleotide sequences of the partial NS5B genome presented the greatest diversity described to date (25.6%), which is comparable to the upper limit of diversity for HCV subtype classification for the same region. Phylogenetic analysis revealed that Brazilian NPHV sequences along with isolates worldwide form two strongly supported clades (pp = 1.0) suggesting the existence of two distinct lineages.

Acupuncture Affects Autonomic and Endocrine but Not Behavioural Responses Induced by Startle in Horses.

Startle is a fast response elicited by sudden acoustic, tactile, or visual stimuli in a variety of animals and in humans. As the magnitude of startle response can be modulated by external and internal variables, it can be a useful tool to study reaction to stress. Our study evaluated whether acupuncture can change cardiac autonomic modulation (heart rate variability); and behavioural (reactivity) and endocrine (cortisol levels) parameters in response to startle. Brazilian Sport horses (n = 6) were subjected to a model of startle in which an umbrella was abruptly opened near the horse. Before startle, the horses were subjected to a 20-minute session of acupuncture in acupoints GV1, HT7, GV20, and BL52 (ACUP) and in nonpoints (NP) or left undisturbed (CTL). For analysis of the heart rate variability, ultrashort-term (64 s) heart rate series were interpolated (4 Hz) and divided into 256-point segments and the spectra integrated into low (LF; 0.01-0.07 Hz; index of sympathetic modulation) and high (HF; 0.07-0.50 Hz; index of parasympathetic modulation) frequency bands. Acupuncture (ACUP) changed the sympathovagal balance with a shift towards parasympathetic modulation, reducing the prompt startle-induced increase in LF/HF and reducing cortisol levels 30 min after startle. However, acupuncture elicited no changes in behavioural parameters.