Impact of dietary Laminaria digitata with alginate lyase or carbohydrase mixture on nutrient digestibility and gut health of weaned piglets.

Laminaria digitata is a brown seaweed rich in prebiotic polysaccharides, mainly laminarin, but its alginate-rich cell wall could compromise nutrient access. Carbohydrase supplementation, such as individual alginate lyase and carbohydrases mixture (Rovabio® Excel AP), could enhance nutrient digestibility and prebiotic potential. This study aimed to evaluate the effect of these enzymes on nutrient digestibility and gut health of weaned piglets fed with 10% L. digitata. Diets did not affect growth performance (P > 0.05). The majority of the feed fractions had similar digestibility across all diets, but the supplementation of alginate lyase increased hemicellulose digestibility by 3.3% compared to the control group (P = 0.047). Additionally, we observed that algal zinc was more readily available compared to the control group, even without enzymatic supplementation (P < 0.001). However, the increased digestibility of some minerals, such as potassium, raises concerns about potential mineral imbalance. Seaweed groups had a higher abundance of beneficial bacteria in colon contents, such as Prevotella, Oscillospira and Catenisphaera. Furthermore, the addition of alginate lyase led to a lower pH in the colon (P < 0.001) and caecum (P < 0.001) of piglets, which is possibly a result of released fermentable laminarin, and is consistent with the higher proportion of butyric acid found in these intestinal compartments. L. digitata is a putative supplement to enhance piglet gut health due to its prebiotic polysaccharides. Alginate lyase supplementation further improves nutrient digestibility and prebiotic potential. These results suggest the potential use of L. digitata and these enzymatic supplements in commercial piglet-feeding practices.

Assessing mineral status in edible tissues of domestic and game animals: a review with a special emphasis in tropical regions.

Mineral status in edible tissues has been extensively studied since the beginning of the twentieth century. Most research focus on nutrition, as the earliest reports were essentially related to nutrition, animal health and mineral deficiencies. Nutrition wise, minerals are of great importance for consumers worldwide, as meat (i.e. beef, pork, chicken) and fish are major sources of protein in human diets. Nutrition gains renewed importance in the tropical context, since tropical forages are poor in minerals. This fact contributes to mineral deficiencies and impaired production performance in extensive production systems, with greater emphasis in ruminant species. In addition to nutrition, several other factors have an important impact in mineral metabolism such as geographic location, gender and species. In this article, we aim to infer on both the role in the organism and the amount present in various edible tissues of different species, either game or production animals, presenting an overall perspective in the context of tropical animal production.

Effect of selenium on growth and antioxidant enzyme activities of wine related yeasts.

The use of supplements in the diet is a common practice to address nutritional deficiencies. Selenium is an essential micronutrient with an antioxidant and anti-carcinogenic role in human and animal health. There is increasing interest in developing nutritional supplements such as yeast cells enriched with selenium. The possibility of producing beverages, namely wine, with selenium-enriched yeasts, led us to investigate the selenium tolerance of six wine related yeasts. The production of such cells may hamper selenium toxicity problems. Above certain concentrations selenium can be toxic inducing oxidative stress and yeast species can show different tolerance. This work aimed at studying selenium tolerance of a diversity of wine related yeasts, thus antioxidant response mechanisms with different concentrations of sodium selenite were evaluated. Viability assays demonstrated that the yeast Torulaspora delbrueckii showed the highest tolerance for the tested levels of 100 µg mL(-1) of sodium selenite. The evaluation of antioxidative enzyme activities showed the best performance for concentrations of 250 and 100 µg mL(-1), respectively for the yeast species Saccharomyces cerevisiae and Hanseniaspora guilliermondii. These results encourage future studies on the possibility to use pre-enriched yeast cells as selenium supplement in wine production.

Growth and physiological responses to cadmium stress of two populations of Dittrichia viscosa (L.) Greuter.

Two clones of Dittrichia viscosa (L.) Greuter from contrasting populations, DV-A (metallicolous) and DV-W (non-metallicolous), were studied to compare Cd accumulation and tolerance. After 10 days of hydroponic culture with 0, 5, 10, and 15 mg Cd L(-1), metal accumulation and plant growth were measured as well as other stress markers such as decrease in the content of photosynthetic pigments, lipid peroxidation, phenols, H(2)O(2), and free proline. We also analyzed the activity of the antioxidant enzymes guaiacol and ascorbate peroxidases, catalase, superoxide dismutase, and glutathione reductase as well as their isoform patterns. Our results confirmed a high Cd tolerance and accumulation in both clones of D. viscosa, which suggests that these traits are constitutive in this species. However, when the Cd concentration in solution exceeded 10 mg Cd L(-1), DV-A was more tolerant than DV-W. The physiological mechanisms involved in Cd tolerance also differed between them, although phenols and guaiacol peroxidase played an important role in both clones. The effective Cd detoxification of DV-A consisted mainly in a promoted ascorbate peroxidase activity and better efficiency of catalase and glutathione reductase enzymes.

Improvement in soil and sorghum health following the application of polyacrylate polymers to a Cd-contaminated soil.

Contamination of soils with cadmium (Cd) is a serious global issue due to its high mobility and toxicity. We investigated the application of insoluble polyacrylate polymers to improve soil and plant health. Sorghum was grown in a Cd-contaminated sandy soil. Polyacrylate polymers at 0.2% (w/w) were added to half of the soil. Control soil without plants was also included in the experiment. Growth of sorghum was stimulated in the polymer-amended soil. The concentration of Cd in the shoots, and the activities of catalase and ascorbate peroxidase decreased in plants from polymer-amended soil compared with unamended control. The amount of CaCl(2)-extractable Cd in the polymer-amended soil was 55% of that in the unamended soil. The Cd extracted in sorghum shoots was 0.19 mg per plant grown on soil without polymer and 0.41 mg per plant grown on polymer-amended soil. The total amount of Cd removed from each pot corresponded to 1.5 and more than 6% of soil CaCl(2)-extractable Cd in unamended and polymer-amended soil, respectively. The activities of soil acid phosphatase, beta-glucosidase, urease, protease and cellulase were greatest in polymer-amended soil with sorghum. In conclusion, the application of polyacrylate polymers to reduce the bioavailable Cd pool seems a promising method to enhance productivity and health of plants grown on Cd-contaminated soils.

Effects of substrate structural analogues on the enzymatic activities of aspartate aminotransferase isoenzymes.

Aspartate aminotransferase (AAT, EC 2.6.1.1) catalyses the transamination of L-asparate to oxaloacetate. It has been reported that AAT from different plant sources can catalyse the transamination of other compounds structurally similar to the natural substrates. Specificity and kinetic studies were performed with two aspartate aminotransferase isoenzymes (AAT-1 and AAT-2) from leaves of Lupinus albus L. cv Estoril using different amino donors and acceptors. Both isoenzymes showed residual activity for some of the substrates tested. Competitive inhibition was found with most of the structural analogues which is typical of a ping-pong bi-bi kinetic mechanism. It was found that both isoenzymes can use 2-amino-4-methoxy-4-oxobutanoic acid as amino donor. AAT-2 uses 2-amino-4-methoxy-4-oxobutanoic acid at a similar rate as L-aspartate but AAT-1 uses this substrate at a slower rate. The use of this amino donor by AAT isoenzymes has not been reported previously, and our results indicate structural differences between both isoenzymes.