Histostructure of different quality classes of fattened liver from mule ducks

This study encompassed a total of 15040 fattened liver samples, obtained during the four seasons of the year. The fattened liver quality was evaluated with regard to its weight and structure and classified in five classes. The analysis of the results indicated that the largest amount of fattened liver from the two highest quality classes – “Esc” and “E” was obtained during the autumn (85.46 % total), whereas in the other seasons the largest amounts of fattened liver were of the “AD” class. The spring was a period when an increase in the relative share of low-quality liver of grade “TV” (20.87 %) and “C” (5.07 %) was detected. The histological studies indicated that hepatocytes with large-drop fatty infil-tration were predominant in liver of classes “Esc” and “E”, with preserved cellular boundaries, with the exception of sporadic cases in the “Esc” class, mostly in the autumn. A specific feature for the “AD” quality class was the prevalence of glandular tubules, with predominantly small- and medium-drop fatty infiltration occurring within their hepatocytes. Seasonal differences in the histostructure of the fattened liver were also detected. In the “TV” quality class two types of glandular tubules with small- and medium-drop fatty infiltration were observed. In some cases, large-drop fatty infiltration could be observed as well – mostly in the summer, and connective tissue between the glandular tubules was preserved, without fattening of its cells. In the “C” quality class, fatty infiltration was in-complete. The histological image showed mostly small-drop fatty infiltration in the cytoplasm of most hepatocytes

Predictors of death and production performance of layer chickens in opened and sealed pens in a tropical savannah environment

BACKGROUND: Layer chickens are exposed to high risks of production losses and mortality with impact on farm profitability. The harsh tropical climate and severe disease outbreaks, poor biosecurity, sub-minimal vaccination and treatment protocols, poor management practices, poor chick quality, feed-associated causes, and unintended accidents oftentimes aggravate mortality and negatively affect egg production. The objectives of this study were to estimate the probability of survival and evaluate risk factors for death under different intensive housing conditions in a tropical climate, and to assess the production performance in the housing systems. RESULTS: Daily mean mortality percentages and egg production figures were significantly lower and higher in the sealed pens and open houses (P < 0. 001) respectively. The total mean feed consumption/bird/day was similar for the open sided and sealed pens but the mean feed quantity per egg produce was significantly lower in the sealed pens ((P < 0.005). Seasons differently impacted on mortality with the hot-dry season producing significantly higher risk of mortality (61 times) and reduced egg production. Other parameters also differed except the egg production during the cold-dry season. Layers in sealed pens appear to have higher probability of survival and the Kaplan-Meir survival curves differed for each pen; ≥78 weeks old layer have higher probability of survival compared with the younger chickens and the 19–38 weeks age category are at highest risk of death (P < 0.001). The hazard-ratio for mortality of layers raised in sealed pens was 0.568 (56.8%). CONCLUSION: Reasons for spiked mortality in layer chickens may not always be associated with disease. Hot-dry climatic environment is associated with heat stress, waning immunity and inefficient feed usage and increase probability of death with reduced egg production; usage of environmentally controlled building in conditions where environmental temperature may rise significantly above 25°C will reduce this impact. Since younger birds (19–38 weeks) are at higher risk of death due to stress of coming into production, management changes and diseases, critical implementation of protocols that will reduce death at this precarious period becomes mandatory. Whether older chickens’ better protection from death is associated with many prophylactic and metaphylactic regimen of medications/vaccination will need further investigation.http://www.biomedcentral.com/bmcvetres/am201