Research on Salmonella in broiler litter reused for up to 14 consecutive flocks.

The reuse of poultry litter is a common practice in the Brazilian poultry industry for flocks of healthy chickens, due to 2 fundamental aspects: production cost and environmental sustainability. Litter is a potentially important source of infection for Salmonella, which requires characterization by microbiological analysis in different aspects of management and reuse. The objective of this study was to verify the occurrence of Salmonella in broiler litters reused up to 14 times in Brazilian poultry farms. From January 2008 to November 2010, 8,877 samples of litter on disposable shoe covers were analyzed from broiler farms located in southern Brazil. At the laboratory, samples were processed for isolation and identification of Salmonella. Of the total 8,877 samples analyzed, only 2.5, 5.27, and 2.08% were positive for Salmonella in the years 2008, 2009, and 2010, respectively. Linear regression models indicate that there is a significant decrease (P < 0.05) in the count of samples positive for Salmonella with the reuse of litter. After the sixth reuse of the litter, values of samples positive for Salmonella are significantly (P < 0.0001) lower than expected (chi-squared test). Results show that the reuse of treated broiler litter is a safe practice and contrary to expectations, it substantially decreases the bacterial load of Salmonella.

The different molecular structure and glycerol-to-fatty acid ratio of palm oils affect their nutritive value in broiler chicken diets.

The aim of this study is to assess how the fat molecular structure and its glycerol-to-fatty acid ratio (G : FA) affect the fatty acid (FA) apparent absorption of palm oils in broiler chickens. The experimental diets were the result of a basal diet supplemented with 6% of different palm oils. Native palm oil (N), rich in triacylglycerols, was the positive control (T1), and acid palm oil (A), rich in free FA, was the negative control (T2). In order to improve the nutritive value of A, two different nutritional strategies were performed. The first strategy was achieved by adding increasing amounts of free glycerol (G) (4% (T3), 8% (T4) and 16% (T5)) to A, and the second one by adding increasing amounts of mono- (MAG) and diacylglycerols (DAG), coming from re-esterified palm oil (E) (40% (T6), 70% (T7), and 100% (T8)) to A. As a result, eight dietary treatments were formulated with a G : FA ratio ranging from 0.04 to 0.67. These treatments were randomly assigned to 192 one-day-old female broiler chickens (Ross 308), distributed in 48 cages. The results showed how, by keeping the G : FA ratio constant (0.33 mol/mol), the diet with a high MAG and DAG content (T7) achieved higher saturated FA apparent absorption values than did the diet with a high triacylglycerol content (T1) and this, in turn, more than did the diet with a high free FA content (T4). The behavior of oils with high or low G : FA ratio was dependent on whether G was in a free state or esterified as part of acylglycerol molecules. Thus, increasing amounts of G to A did not enhance the total FA apparent absorption, but rather quite the opposite, even impairing the absorption of mono- and polyunsaturated FA. However, increasing amounts of E (rich in MAG and DAG) to A (rich in FFA) did enhance total FA apparent absorption, primarily due to the increased absorption of saturated FA. In conclusion, the greater the G : FA ratio of a palm oil, the greater the absorption of total FA, as long as G is esterified as part of acylglycerol molecules. Thus, the re-esterification process for obtaining E makes sense in order to give added value to A, achieving even greater digestibility values than does its corresponding N.