Impact of a Single Oral Acute Dose of Aflatoxin B1 on Liver Function/Cytokines and the Lymphoproliferative Response in C57Bl/6 Mice.

Aflatoxin B1 (AFB1), a mycotoxin found in food and feed, exerts harmful effects on humans and animals. The liver is the earliest target of AFB1, and its effects have been evaluated in animal models exposed to acute or chronic doses. Considering the possibility of sporadic ingestion of AFB1-contaminated food, this study investigated the impact of a single oral dose of AFB1 on liver function/cytokines and the lymphoproliferative response in mice. C57BL/6 mice were treated with a single oral AFB1 dose (44, 442 or 663 µg AFB1/kg of body weight) on the first day. Liver function (ALT, γ-GT, and total protein), cytokines (IL-4, IFN-γ, and IL-17), histopathology, and the spleen lymphoproliferative response to mitogens were evaluated on the 5th day. Although AFB1 did not produce any significant changes in the biochemical parameters, 663 µg AFB1/kg-induced hepatic upregulation of IL-4 and IFN-γ, along with liver tissue injury and suppression of the lymphoproliferative response to ConA (p < 0.05). In conclusion, a single oral dose of AFB1 exposure can induce liver tissue lesions, liver cytokine modulation, and immune suppression in C57BL/6 mice.

Intense Exercise and Aerobic Conditioning Associated with Chromium or L-Carnitine Supplementation Modified the Fecal Microbiota of Fillies.

Recent studies performed in humans and rats have reported that exercise can alter the intestinal microbiota. Athletic horses perform intense exercise regularly, but studies characterizing horse microbiome during aerobic conditioning programs are still limited. Evidence has indicated that this microbial community is involved in the metabolic homeostasis of the host. Research on ergogenic substances using new sequencing technologies have been limited to the intestinal microbiota and there is a considerable demand for scientific studies that verify the effectiveness of these supplements in horses. L-carnitine and chromium are potentially ergogenic substances for athletic humans and horses since they are possibly able to modify the metabolism of carbohydrates and lipids. This study aimed to assess the impact of acute exercise and aerobic conditioning, associated either with L-carnitine or chromium supplementation, on the intestinal microbiota of fillies. Twelve "Mangalarga Marchador" fillies in the incipient fitness stage were distributed into four groups: control (no exercise), exercise, L-carnitine (10g/day) and chelated chromium (10mg/day). In order to investigate the impact of acute exercise or aerobic conditioning on fecal microbiota all fillies undergoing the conditioning program were analyzed as a separate treatment. The fillies underwent two incremental exercise tests before and after training on a treadmill for 42 days at 70-80% of the lactate threshold intensity. Fecal samples were obtained before and 48 h after acute exercise (incremental exercise test). Bacterial populations were characterized by sequencing the V4 region of the 16S rRNA gene using the MiSeq Illumina platform, and 5,224,389 sequences were obtained from 48 samples. The results showed that, overall, the two most abundant phyla were Firmicutes (50.22%) followed by Verrucomicrobia (15.13%). The taxa with the highest relative abundances were unclassified Clostridiales (17.06%) and "5 genus incertae sedis" from the phylum Verrucomicrobia (12.98%). There was a decrease in the phylum Chlamydiae and in the genus Mycobacterium after the second incremental exercise test. Intense exercise changed the community's structure and aerobic conditioning was associated with changes in the composition and structure of the intestinal bacterial population of fillies. The intra-group comparison showed that chromium or L-carnitine induced moderate changes in the fecal microbiota of fillies, but the microbiota did not differ from the control group, which was exercised with no supplementation. Fecal pH correlated positively with Simpson's index, while plasma pH correlated negatively. Our results show that exercise and aerobic conditioning can change in the microbiota and provide a basis for further studies enrolling a larger number of horses at different fitness levels to better understand the effects of exercise and training on the intestinal microbiota of horses.

Transferência de imunidade passiva em bezerros das raças Nelore e Limousin e proteinograma sérico nos primeiros quatro meses de vida / Passive transfer of immunity in Nelore and Limousin calves and serum proteinogram in the first four months of life

To study the passive transfer of immunity, 90 healthy calves, 45 Nelore and 45 Limousin, were grouped (n=15) according to their dam's parity: first, second or third or more calvings. Blood samples were draw from each calf with 24 to 36 hours of life and 15, 30, 60, 90, and 120 days. The total serum (TSP) and plasma (TPP) proteins, gamaglutamiltransferase activity (GGT), serum albumin, alpha, beta and gammaglobulin by electrophoresis in agarose gel and IgG estimated by the zinc sulphate turbidity test were determined. Two-way-ANOVA was used to compare the data in the first age. The age behaviour was analysed through repeated measures ANOVA. Correlations were established between the variables. The passive transfer of immunity was successful in both breeds and the parity of the dam had no effect on the calves' serum gammaglobulin concentration. The levels of gammaglobulins were higher at the end of the first day of life, and decreased until 60 days. From there on, the increase due to the active production of antibodies was precocious in taurine calves and slower in Zebu calves. At the end of the first day of life, the gammaglobulin was correlated with IgG (r=0,859), TPP (r=0,807), TSP (r=0,811) and GGT (r=0,399). The variation of serum proteins followed the normal pattern throughout the first four months of life, with little differences between taurine and Zebu calves.

Com o objetivo de investigar alguns aspectos relacionados à transferência de imunidade passiva em bovinos de corte, foram selecionados 90 bezerros aparentemente sadios, 45 da raça Nelore e 45 da raça Limousin, distribuídos em 3 grupos (com 15 bezerros cada) de acordo com o número de parições de suas mães: primeira cria; segunda cria; e terceira ou mais crias. Amostras de sangue foram colhidas de cada bezerro entre 24 e 36 horas de vida e com 15, 30, 60, 90 e 120 dias. Determinaram-se as concentrações de proteína total no soro (PT) e no plasma (PPT), a atividade sérica da gamaglutamiltransferase (GGT), e as concentrações séricas de albumina, alfa, beta e gamaglobulinas por eletroforese em gel de agarose e de IgG estimada por meio do método de turvação pelo sulfato de zinco. Empregou-se a análise de variância bifatorial para as variáveis mensuradas na primeira colheita. O comportamento das variáveis em função da idade foi estudado por meio da análise de variância de medidas repetidas. Correlações foram estabelecidas entre as variáveis. A transferência de imunidade passiva foi bem sucedida nos bezerros de ambas as raças e o número de parições das mães não interferiu no processo. As concentrações mais elevadas de gamaglobulinas ao término do primeiro dia de vida declinaram até valores mínimos aos 60 dias. A partir dessa idade, a elevação conseqüente à produção ativa de anticorpos foi mais precoce nos bezerros taurinos e mais lenta nos zebuínos. A gamaglobulina, ao término do primeiro dia de vida, correlacionou-se com as seguintes variáveis: IgG (r=0,859), PPT (r=0,807), PT (r=0,811) e GGT (r=0,399). O fator etário exerceu efeito sobre todas as variáveis mensuradas. As variações das proteínas séricas obedeceram a um padrão de comportamento fisiológico ao longo dos quatro primeiros meses de vida, de forma geral, não distinto em taurinos e zebuínos.

Metabolismo oxidativo dos neutrófilos de bezerros das raças Nelore e Limousin nos primeiros quatro meses de vida / Neutrophil oxidative burst in Nelore and Limousin calves in the first four months of life

To study some defence mechanisms of beef calves kept on range conditions, 90 healthy calves, 45 Nelore and 45 Limousin, were bled at 24 to 36 hours of life, 15, 30, 60, 90 and, 120 days. Leukogram and neutrophil oxidative burst through the non-stimulated and the stimulated NBT tests were determined. The parasitemia with Anaplasma marginale, Babesia bigemina and B. bovis was investigated. Repeated measure ANOVA was used to analyse the age effect on leukocyte counts. Variation of positive neutrophil throughout the age was analysed through Krushkal-Wallis test. Comparisons among breeds were done using the Mann-Whithney test. The white blood cell count increased with age in both breeds, with a decrease in neutrophil and an increase in lymphocyte counts. The neutrophil lymphocyte ratio had been inverted before 15 days of life. The neutrophil oxidative burst was less effective in the newborn calves increasing with age. Limousin calves' neutrophils had higher capacity to reduce NBT in advanced ages. The observed differences between taurine and Zebu calves had no effects on calves' health and could be atributed to Anaplasma marginale natural and asynptomatic infection.

Com o objetivo de investigar alguns mecanismos de defesa em bezerros de raças de corte criadas a campo, foram utilizados 90 animais recém-nascidos aparentemente sadios, 45 da raça Nelore e 45 da raça Limousin. Amostras de sangue foram colhidas de cada bezerro entre 24 e 36 horas de vida e aos 15, 30, 60, 90 e 120 dias. Determinaram-se o leucograma e o metabolismo oxidativo dos neutrófilos por meio do teste da redução do tetrazólio de nitroazul (NBT), provas não estimulada (NBT-NE) e estimulada (NBT-E). Investigou-se a taxa de parasitemia determinada por Anaplasma marginale, Babesia bigemina e B. bovis. Utilizou-se a análise de variância de medidas repetidas para estudar o comportamento das variáveis hematológicas com o avançar da idade. O teste de Krushkal-Wallis foi empregado para caracterizar a variação da porcentagem de neutrófilos reativos relacionada à idade. Comparações entre as raças foram realizadas em cada idade por meio do teste de Mann-Whithney. A contagem total de leucócitos aumentou com a idade nas duas raças estudadas. Observou-se diminuição do número de neutrófilos e aumento do de linfócitos, ocorrendo sua inversão antes dos 15 dias de idade. A capacidade oxidativa dos neutrófilos foi menor nos bezerros recém-nascidos e aumentou com o avançar da idade. Os neutrófilos dos bezerros Limousin apresentaram maior capacidade de redução do NBT do que os dos bezerros Nelore, notadamente após o segundo mês de vida. Essa diferença não provocou reflexos sobre a saúde dos animais e pode ser resultado da infecção natural e assintomática com o Anaplasma marginale.