Relación entre el nivel de grasa e ingestión y la excreción urinaria de nitrógeno y energía, en gazapos en crecimiento-cebo

Se determinó la excreción urinaria de nitrógeno (NU, %) y de energía (EU, kcal/100g), en la última semana de vida, de 36 conejos alimentados, desde el destete (a los 28 d) hasta el sacrificio a los dos meses de edad, con tres piensos conteniendo 0, 3 y 6 % de grasa añadida (G0, G3 y G6); y administrados a dos niveles de ingestión: ad libitum (IL) y restringido (IR) al 70 % de IL. El NU y la EU estuvieron influidos positivamente tanto por el nivel de ingestión (P<0,001) como por el % de grasa ingerida (P<0,05). En estos resultados puede estar involucrado el metabolismo tan elevado de las lipoproteínas transportadoras de lípidos, implicadas en el metabolismo de las grasas, ya sean de origen alimentario o de la lipogénesis de novo. La relación entre la EU y el NU aporta valores muy superiores a los que podría corresponder a las materias orgánicas nitrogenadas, por lo que se podría pensar, como posible causa, en la intervención de materia orgánica no nitrogenada. Asimismo, la cuantificación de la EM del pienso se ve afectada por el incremento del valor calórico de la orina, con el nivel de ingestión y/o el 6 % de grasa añadida. Con ello se evidencia la desigualdad entre ED y EM de la grasa en las raciones que las incluya. Asimismo, el hecho de que la movilización grasa —bien sea de origen alimentario o de la lipogénesis— altere la excreción nitrogenada y/o energética a través de la orina, pone de manifiesto la importancia de su consideración, especialmente cuando dicha pérdida puede afectar a los rendimientos de algunas producciones animales.

Seroprevalence of Angiostrongylus cantonensis in wild rodents from the Canary Islands

Background: Angiostrongylus cantonensis is a lungworm of rats (Muridae) that is the causative agent of human cerebral angiostrongyliasis. The life cycle of A. cantonensis involves rats and mollusks as the definitive and intermediate hosts, respectively. This study was designed to increase the knowledge about the occurrence and distribution of A. cantonensis in its definitive host in the Canary Islands, using parasitological and serological analysis in different areas and age groups.Methodology/Principal Findings: Between 2009 and 2010, 54 black rats (Rattus rattus) from Tenerife were captured from six human-inhabited areas and sera samples were obtained. The lung nematodes were identified by morphological and molecular tools as A. cantonensis. The 31-kDa glycoprotein antigen was purified from A. cantonensis adult worms by electrophoresis and electroelution. Of the 54 tested rodents, 30 showed IgG antibodies against A. cantonensis 31-kDa antigen by ELISA. Therefore, the overall seroprevalence was 55.6% (95% CI: 42.4-68). Seroprevalent rodents were found in all the 6 areas. This 31-kDa antigen was not recognized by some sera of rats infected by other helminth species (but not A. cantonensis). Seroprevalence of IgG antibodies against A. cantonensis and prevalence based on the presence of adult worms showed significant correlation (R2 = 0.954, p,0.05). Conclusions/Significance: The present results could indicate a high prevalence of A. cantonensisin Tenerife and suggest the inclusion of two new zones in the distribution area of the parasite. The commonness and wide distribution of A. cantonensis in rats implies the presence of intermediate hosts, indicating that humans may be at risk of getting infected.

Moderately oxidized oils and dietary zinc and alpha-tocopheryl acetate supplementation: effects on the oxidative stability of rabbit plasma, liver, and meat

The aim of this study was to assess the alterations in plasma, liver, and meat oxidative stability and R-tocopherol content when moderately oxidized sunflower oils were added to feeds and when feeds were supplemented with R-tocopheryl acetate (100 mg/kg) and Zn (200 mg/kg). The effects of cooking the meat and its subsequent refrigeration were also studied. When the content of primary oxidation compounds of the oil was high, rabbit plasma, liver, and meat R-tocopherol content was reduced and meat susceptibility to oxidation increased. The addition of oil with a high content of secondary oxidation compounds (oil heated at 140 'C, 31 h) to feed also led to an increase in meat susceptibi- lity to oxidation, although it presented an R-tocopherol content similar to that of nonheated oil. Feed supplementation with R-tocopheryl acetate increased tissue R-tocopherol content and improved the oxidative stability of liver and meat. However, in the latter, it was less effective when oil heated at 55 'C was added.

Oxidized oils and dietary zinc and alpha-tocopheryl acetate supplementation: effects on rabbit plasma, liver and meat fatty acid composition and meat Zn, Cu, Fe and Se content

The effects of the addition of heated oils to feeds (3%, w/w) and the dietary supplementation with a-tocopheryl acetate (TA; 100 mg/kg) and Zn (200 mg/kg) on rabbit tissue fatty acid (FA) composition and on the Zn, Cu, Fe and Se content in meat were assessed. Heating unrefined sunflower oil (SO) at 558C for 245 h increased its content in primary oxidation products and reduced its a-tocopherol content. However, this did not significantly affect tissue FA composition. Heating SO at 1408C for 31 h increased its content in secondary oxidation products and in some FA isomers asc9,t11-CLA and di-trans CLA. This led to increases in di-trans CLA in liver and in t9,c12-18:2 in meat. The c9,t11-CLA was the most incorporated CLA isomer in tissues. The dietary supplementation with a-TA did not affect the FA composition of plasma, liver or meat. The cooking of vacuum-packed rabbit meat at 788C for 5 min reduced significantly but slightly its polyunsaturated FA content. The dietary supplementation with Zn did not modify the content of Zn, Fe or Se in meat, but it reduced its Cu content. On the other hand, it increased the content of some FAs in meat when SO heated at 1408C for 31 h was added to feeds.