Presença de formas amastigotas de Leishmania chagasi e perfil leucocitário no aparelho reprodutivo de cães

A leishmaniose visceral (LV) é uma zoonose causada pelo protozoário Leishmania (Leishmania) chagasi. A leishmaniose visceral canina (LVC) é a doença de maior relevância zoonótica. Usualmente, a infecção ocorre entre um hospedeiro invertebrado para um hospedeiro vertebrado, entretanto, a transmissão na ausência do vetor já é conhecida. O objetivo principal deste estudo foi identificar a presença de formas amastigotas, quantificar as células leucocitárias, estimar o risco relativo da presença de formas amastigotas no aparelho reprodutivo de cães sorologicamente positivos com e sem sinais clínicos. Para isso, foram utilizados cães sem raça definida, sexualmente maduros e testados sorologicamente para LVC (com sinais clínicos, n=25; sem sinais clínicos, n=25), que após eutanásia, tiveram fragmentos de testículo, epidídimo (cabeça, corpo e cauda) e glândula prostática (selecionados ao acaso) impressos em lâminas. Um grupo de 20 cãs sorologicamente negativos e sem sinais clínicos foi usado como controle. Amostras do baço foram incluídas como controle parasitológico positivo. O percentual de linfócitos foi superior (P<0,05) no corpo e cauda do epidídimo, assim como no testículo. Macrófagos foram superiores (P<0,05) apenas nas regiões do corpo e cauda epididimais. A presença de amastigotas correlacionou-se entre as distintas regiões do aparelho reprodutivo. Nos sintomáticos variaram entre 0,50 a 0,80 e entre 0,79 a 0,95 nos assintomáticos. A presença de amastigotas no testículo dos cães sintomáticos foi 6,5 vezes superior aos cães assintomáticos. Os resultados obtidos demonstram o potencial epidemiológico da transmissão venérea da doença, principalmente em áreas onde os programas de controle da LVC não consideram esta forma de transmissão, que pode ser importante em populações caninas não esterilizadas

Relationships among body composition, circulating concentrations of leptin and follistatin, and the onset of puberty and fertility in young female sheep

The onset of puberty depends on the attainment of critical body mass, so should also be affected by increases in the rate of accumulation of muscle and adipose tissue. Adipose tissue and reproduction are linked by leptin. For muscle, a link has not yet been identified, although one possibility is follistatin. We assessed the relationships among circulating concentrations of follistatin and leptin and the rates of growth and accumulation of muscle and fat during pubertal development in female sheep. We used 326 animals with known phenotypic values for live weight (LW), depths of eye muscle (EMD) and fat (FAT), and known breeding values at post-weaning age for body mass (PWT) and depths of eye muscle (PEMD) and fat (PFAT). Leptin concentration was positively correlated with values for EMD, PEMD, FAT, PFAT, LW and PWT (P < 0.001), whereas follistatin concentration was negatively correlated with values for EMD and PWT (P < 0.001), and PEMD (P < 0.01) and FAT (P < 0.05). Leptin concentration was negatively related to age and positively related to live weight at first oestrus and the proportion of females that attained puberty (P ≤ 0.05), and to fertility and reproductive rate (P < 0.01). Follistatin concentration was negatively related to live weight at first oestrus and to fertility (P < 0.01) and reproductive rate (P < 0.05). There were positive correlations (P < 0.001) between muscle accumulation and leptin concentration, and between muscle accumulation and reproductive performance. We conclude that leptin and follistatin are probably both involved in effects of accelerated accumulation of muscle and adipose tissues on the onset of puberty

Liveweight loss in adult ewes is affected by their sires breeding values for fat and muscle

Ewes that lose more weight at times of nutritional pressure may decrease farm profitability through reduced production but also through reduced stocking rates, increased supplementary feeding costs and labour. Liveweight profiles were derived from the splined liveweight data of adult ewes from the Sheep CRC Information Nucleus Flock and liveweight loss was analysed. This paper reports on the response of liveweight loss to sire breeding values for fat and muscle in two contrasting environments. Overall liveweight loss was affected by significant differences between site, sire breed, ewe age, and previous and current reproductive performance. Sire breeding values for fat were significant, and interacted with site. There was a reduction in liveweight loss as sire breeding values for fat increased at Katanning in WA but an increase in liveweight loss at Kirby in NSW. Sire breeding values for muscle were also significant and different for each site, with the effects being opposite to fat at each site. These results suggest that selection against fat or selection for increased muscling may compromise the ability of ewes to maintain weight during summer and autumn in dry Mediterranean climates, however this may not be applicable for all environments