Effects of pH and fermentative substrate on ruminal metabolism of fatty acids during short-term in vitro incubation.

The ruminal biohydrogenation of c9,c12-18:2 can be affected by the fibre/starch ratio of the diet and the ruminal pH. The objectives of this study were to examine independently in vitro the effects of fermentation substrate (hay vs. corn starch) and buffer pH (6 vs. 7) on the biohydrogenation of c9,c12-18:2 carried out by grape seed oil, focusing on its t11 and t10 pathways, using 6-h ruminal incubations. The experimental design was a 2 × 2 factorial arrangement. Fermentation substrate and pH affected the C18 fatty acid balance in incubated media, but few interactions were observed. Compared with starch, hay as the fermentation substrate favoured the production of 18:0 (×2.3), all trans-18:1 isomers (×12.6) and CLA (×6.1), except c9,t11-CLA, and the disappearance of unsaturated C18 fatty acids, but decreased the production of odd and branched chain fatty acids. Compared with pH 6 buffer, pH 7 buffer resulted in higher c9,c12-18:2 disappearance and CLA production. For c9,t11-CLA, an interaction was noticed between the two factors, leading to the highest production in cultures incubated on hay with the 7 pH buffer. Compared with starch, hay as fermentation substrate favoured the activity of t11 producers, which are fibrolytic bacteria, and the production of t10 isomers, possibly due to the presence of potential t10 producers in hay. Low pH resulted in a decreased t11 isomers production and in a slightly increased t10 isomers production, probably due to a modulation of enzymatic or bacterial activity.

Identification of undeclared sources of animal origin in canine dry foods used in dietary elimination trials.

Failure to respond to commercial limited antigen diets can occur in dogs kept on a dietary trial for the diagnosis of adverse food reaction (AFR). The aim of this study was to assess twelve canine dry limited antigen diets (eleven novel protein diets and one hydrolysed diet) for potential contamination by ingredients of animal origin not mentioned on the label. The validity of the two methods adopted for the detection of such food antigens was also evaluated. Each dietary product was analysed by microscopy analysis using the official method described in Commission Regulation EC 152/2009 with the aim of identifying bone fragments of different zoological classes (mammalian, avian and fish) and by polymerase chain reaction (PCR) for the identification of DNA of animal origin. Discrepancies between the results obtained by PCR and/or microscopy analysis and the ingredients listed on pet food packages were found. Only in two pet foods did the results of both analyses match the ingredients listed on the label. In the remaining ten samples, microscopy detected bone fragments from one or two unpredicted zoological classes, revealing avian fragments in six of ten samples followed by those of fish in five of ten and mammalian fragments in four of ten. In two samples, microscopy analysis identified a contamination that would have otherwise passed unobserved if only PCR had been used. However, PCR confirmed the presence of all the zoological classes detected by microscopy and also identified the DNA of an additional unexpected zoological class in two samples. Dogs might fail to respond to commercial limited antigen diets because such diets are contaminated with potential allergens. Both PCR and microscopy analysis are required to guarantee the absence of undeclared animal sources in pet foods. Before ruling out AFR, a novel protein home-made diet should be considered if the dog is unresponsive to a commercial regimen.

The major epidemic infections: a gift from the Old World to the New?

With the discovery of the New World, the Europeans flocked to America and with them spread infectious diseases. During long sea voyages the agents of these diseases increased their diffusion capacity in a suitable environment. Lack of hygiene, fatigue and privations, a diet without vitamins and many persons kept in confined spaces were the essential features of this environment. Sick persons, whose health conditions worsened during the journey to the New World, carried the germs of infectious diseases. The first disease to appear in the New World was smallpox described in 1518 in Hispaniola. From there the disease moved rapidly to Mexico in 1520, exterminating most of the Aztecs, Guatemala and to the territories of Incas from 1525-26, killing most of them and the King himself. The second disease, influenza, appeared in La Isabela, a few years later, causing a heavy epidemic between 1558 and 1559. Other diseases followed such as yellow fever and malaria. So Europeans and these invisible and mortal agents caused enormous destruction of American populations. In fact historians have estimated that beginning from early 1500, in only 50 years the population of Peru and Mexico fell from 60 to 10 million; in the latter country, in one century, the populations fell from an initial 10 million to only 2 million.

Asbestos hazards in the city of Rome, Italy.

A review is made of asbestos as a health hazard, and attention is drawn to possible dangers due to exposure to asbestos in the city of Rome in and outside the work place. The exposure to asbestos of workers of the ATAC company (the public concern of urban passenger transport of Rome) is examined. This is particularly dangerous for workers who repair equipment with asbestos components, such as brake linings. Exposure to asbestos may also occur in inhabitants who live and work close to where asbestos fibres collect. The study evaluates the contamination of asbestos fibres in both work and urban environment among people directly or indirectly exposed to this pollutant.