Intra-phylum and inter-phyla associations among gastrointestinal parasites in two wild mammal species.

A growing body of literature reveals that the interactions among the parasite community may be strong and significant for parasite dynamics. There may be inter-specific antagonistic interactions as a result of competition and cross-effective immune response, or synergistic interactions where infection by one parasite is facilitated by another one, either by an impoverishment of the host's defenses, parasite-induced selective immunosuppression, or trade-offs within the immune system. The nature of these interactions may depend on how related are the parasite species involved. Here we explored the presence of associations among gastrointestinal parasites (coccidia and helminths) in natural populations of two wild mammal species, the capybara (Hydrochoerus hydrochaeris) and the guanaco (Lama guanicoe). The associations explored were between the oocyst outputs of a selected Eimeria species and the other coccidia of that parasite community, and between Eimeria spp. and the predominant nematodes. The statistical analysis included adjustment for potential confounders or effect modifiers. In guanacos, the prevailing interactions were synergistic among the coccidia and between coccidia and nematodes (Nematodirus spp.). However, in capybaras, the interaction between nematodes (Viannaiidae) and Eimeria spp. depended on environmental and host factors. The relationship was positive in some circumstances (depending on season, year, sex, or animal size), but it appeared to become antagonistic under different scenarios. These antagonist interactions did not follow a particular seasonal pattern (they occurred in autumn, spring, and summer), but they were predominantly found in females (when they depended on sex) or in 2010 and 2011 (when they depended on the sampling year). These results suggest that the relationship between coccidia and nematodes in capybaras may be context dependent. We propose that the context-dependent immune investment documented in capybaras may be the cause of these varying interactions.

Effects of olive maturation and stoning on quality indices and antioxidant content of extra virgin oils (cv. Coratina) during storage.

UNLABELLED: Quality indices, antioxidant compounds, and antioxidant activities of extra-virgin oils from Coratina olives were evaluated during a 12-mo storage. Whole and stoned olives, picked at 2 different maturation index (MI), were submitted to malaxation for 45 min and extracted by a 3-phase continuous system. A 90-min malaxation trial was also performed for the stoned olives. The following parameters were monitored: free acidity, peroxide value, K(232) and K(270) indices, sensory profile, total phenolic content (TPC), phenolic profiles, tocopherol compounds, and antioxidant activity (AA). The highest TPC, AA, and sensory score were found for the oils obtained by olives picked at low MI and by stoned olives. After 12 mo, all the oils were still included into the "extra-virgin" category, and those deriving from whole olives picked at the lowest MI showed the best sensory characteristics due to high fruity and well-balanced pungent and bitter tastes. PRACTICAL APPLICATION: This study could represent a helpful tool for oil-makers to improve the marketing of extra-virgin olive oils produced from cultivars with very high phenolic contents, such as Coratina, generally not adequately appreciated by consumers because of their excessive bitterness and pungent taste. These oils, when extracted from whole olives, are generally consumed after a certain period of time (at least 6 mo) during which a decrease in the phenolic content occurs. The results of the present work demonstrate that oils extracted from olives picked at low maturation index can be marketed immediately after production if subjected to stoning and malaxed for a short time. This procedure allows to adjust the phenolic content and to obtain a high flavor and a well-balanced taste.

Changes in phenolic content and antioxidant activity of Italian extra-virgin olive oils during storage.

Phenolic composition and antioxidant activity of extra-virgin olive oils extracted from several Italian varieties were studied at production and during storage. The antioxidant activity was measured according to the following tests: in the aqueous phase, by radical scavenging of the 2,2'-azino-bis(3-ethylbenzthiazoline-6-sulfonic acid) (ABTS) radical cation; and in the lipid phase, using the beta-carotene bleaching method. The phenolic content was not correlated to the oxidation indices (peroxide value and spectrophotometric constants). The phenolic contents and profiles of the various cultivars showed remarkable differences. The phenolic content was strongly correlated with the antioxidant activity measured according to the beta-carotene test and weakly correlated with the radical scavenging ability.