Dog skin parasite load, TLR-2, IL-10 and TNF-α expression and infectiousness.

Visceral leishmaniosis is a zoonotic disease that is transmitted by Lutzomyia longipalpis sandflies. Dogs are the main peri-urban reservoir of the disease, and progression of canine leishmaniosis is dependent on the type of immune response elaborated against the parasite. Type 1 immunity is characterized by effective cellular response, with production of pro-inflammatory cytokines such as tumour necrosis factor alpha (TNF-α). In contrast, Type 2 immunity is predominantly humoral, associated with progression of the disease and mediated by anti-inflammatory cytokines such as interleukin 10 (IL-10). Although seemly important in the dynamics of leishmaniosis, other gene products such as toll-like receptor 2 (TRL-2) and inducible nitric oxide synthase (iNOS) exert unclear roles in the determination of the type of immune response. Given that the dog skin serves as a micro-environment for the multiplication of Leishmania spp., we investigated the parasite load and the expression of TLR-2, iNOS, IL-10 and TNF-α in the skin of 29 infected and 8 control dogs. We found that increased parasite load leads to upregulation of TLR-2, IL-10 and TNF-α, indicating that abundance of these transcripts is associated with infection. We also performed a xenodiagnosis to demonstrate that increased parasitism is a risk factor for infectiousness to sandflies.

Biomassa de Rubrivivax gelatinosus na criação de frangos de corte: desempenho animal e cor dos produtos / Biomass of Rubrivivax gelatinosus in broiler chicken feeding: animal performance and color of products

A bactéria Rubrivivax gelatinosus tem sido utilizada experimentalmente no tratamento despoluente de efluentes industriais de abatedouros de aves e peixes, originando uma biomassa contendo pigmentos carotenoides, substâncias que possuem a capacidade de conferir cor aos alimentos e proteger contra reações oxidativas. Este trabalho teve por objetivo verificar o efeito da biomassa de R. gelatinosus adicionada à alimentação de frangos de corte sobre o desempenho animal e a cor de carne e pele. Duzentos pintos machos Cobb 500 foram distribuídos aleatoriamente em 20 boxes para receber, do 36º ao 45º dia de criação, quatro tratamentos com diferentes quantidades de biomassa na ração (T1 [controle] - 0g/kg; T2 - 1g/kg; T3 - 2g/kg; T4 - 3g/kg), em cinco repetições. As pesagens de aves e rações para a análise de desempenho foram feitas no início da criação e ao fim de cada período de crescimento. Ao final do experimento (45 dias), 20 aves de cada tratamento foram abatidas para a determinação da cor objetiva (L - luminosidade, C - saturação, h - tom) em pele e carne de peito e coxa. Os resultados obtidos foram submetidos à ANOVA, teste t para a comparação múltipla de médias e análise de regressão com nível de significância de 5%. O ganho de peso e o consumo das aves não diferiram estatisticamente entre si (P>0,05), enquanto o índice de conversão alimentar foi superior para o T1. A luminosidade da carne e da pele aumentou significativamente nos tratamentos que receberam a biomassa. O tom da cor em carne e pele aumentou em direção ao amarelo até a concentração de 2g de biomassa por kg de ração, ao passo que, na concentração de 3g/kg, o aumento foi em direção à tonalidade vermelha. Somente na carne da coxa a saturação da cor sofreu influência da presença da biomassa na dieta. Concluiu-se que, até a proporção de 3g/kg, a biomassa não prejudicou o desempenho e foi eficiente em pigmentar a pele e a carne de frangos de corte...

The phototrophic bacterium Rubrivivax gelatinosus has been used experimentally for the depollution of industrial effluents from broiler and fish slaughterhouses, resulting in a biomass containing oxycarotenoids, substances that impart color and protection against to oxidative reactions. This work aimed to check the effect of R. gelatinosus biomass added into broiler chickens' feed on animal performance and meat/skin color. Two hundred Cobb 500 male chicks were randomly divided into 20 boxes to receive, from the 36th to the 45th day of rearing, 4 treatments with different amounts of biomass in the diets (T1 [control] - 0g/kg; T2 - 1g/kg; T3 - 2g/kg; T4 - 3g/kg), in 5 replicates. Chickens and rations were weighted at the beginning of the rearing time and at the end of each growth phase to assess animal performance. At the end of the experiment (45 days), 20 birds from each repetition were slaughtered for the evaluation of the objective color (L - lightness, C - chroma, h - hue) on skin and meat of breast and thigh. Statistical analyses comprised ANOVA, t test for means comparison and regression analysis, at 5% significance level. Weight gain and feed consumption did not differ statistically (P>0.05), while feed conversion was better for T1. Lightness of meat and skin increased significantly in the treatments with the biomass supplementation. Hue angle of meat and skin increased towards yellow until 2g biomass/kg and towards red at 3g/kg. Chroma was only influenced by the presence of the biomass in thigh meat. It was concluded that the addition of the biomass up to 3g/kg was not harmful to birds' performance and was efficient to cause changes in the color of broiler skin and meat...

Neutrophil dysfunction varies with the stage of canine visceral leishmaniosis.

Canine visceral leishmaniosis (CVL) causes a dependent-stage alteration in neutrophil oxidative metabolism. When production of reactive oxygen species (ROS) exceeds the antioxidant capacity of neutrophils, apoptosis is triggered, impairing the viability and function of these cells, which can predispose dogs to infection. However, the uremic condition observed in late-stage CVL can also alter the viability and function of human neutrophils. To more clearly understand this relationship, the apoptosis rate and oxidative metabolism of neutrophils from control dogs (n=20) were compared to dogs in moderate (n=15) and very severe (n=15) stage CVL, classified according to LeishVet Consensus. To assess neutrophil oxidative metabolism, superoxide production was measured using the nitroblue tetrazolium reduction test (NBT) in isolated neutrophils. The apoptosis rate of neutrophils was estimated using the morphological method. Moderate-stage dogs presented increased superoxide production, while dogs with very severe stage CVL presented decreased superoxide production and an increase neutrophil apoptosis rate. Leishmaniosis causes differential neutrophil dysfunction according to disease stage. In moderate stage CVL, increased superoxide production is observed with no change in neutrophil viability. However, in very severe stage CVL, decreased superoxide production and increased apoptosis occur associated with uremia.