RESUMO
Drainage has turned 650,000 km2 of peatlands worldwide into greenhouse gas sources. To counteract climate change, large-scale rewetting is necessary while agricultural use of rewetted areas, termed paludiculture, is still possible. However, more information is required on the performance of suitable species, such as cattail, in the range of environmental conditions after rewetting. We investigated productivity and biomass quality (morphological traits and tissue chemical composition) of Typha angustifolia and Typha latifolia along gradients of water table depth (-45 to +40 cm) and nutrient addition (3.6-400 kg N ha-1 a-1) in a six-month mesocosm experiment with an emphasis on their high-value utilization, e.g., as building material, paper, or biodegradable packaging. Over a wide range of investigated conditions, T. latifolia was more productive than T. angustifolia. Productivity was remarkably tolerant of low nutrient addition, suggesting that long-term productive paludiculture is possible. Low water tables were beneficial for T. latifolia productivity and high water tables for T. angustifolia biomass quality. Rewetting will likely create a mosaic of different water table depths. Our findings that the yield of T. angustifolia and tissue chemical composition of T. latifolia were largely unaffected by water table depth are therefore promising. Depending on intended utilization, optimal cultivation conditions and preferable species differ. Considering yield or diameter, e.g., for building materials, T. latifolia is generally preferable over T. angustifolia. A low N, P, K content, high Si content and high C/N-ratio can be beneficial for processing into disposable tableware, charcoal, or building material. For these utilizations, T. angustifolia is preferable at high water tables, and both species should be cultivated at a low nutrient supply. When cellulose and lignin contents are relevant, e.g., for paper and biodegradable packaging, T. angustifolia is preferable at high water tables and both species should be cultivated at nutrient additions of about 20 kg N ha-1 a-1.
RESUMO
The objective of our studies was to investigate effects of carnosic acid (CA), selenized yeast (SeY) and selenate (SeVI) added to the diet including rapeseed oil (RO) and fish oil (FO) on concentrations of elements, fatty acids (FAs), tocopherols, cholesterol, and malondialdehyde in the liver, heart, musculus longissimus dorsi (MLD), and musculus biceps femoris (MBF) of lambs. Lambs were fed diets: group I-the basal diet (BD) with RO; group II-BD with RO and FO; group III-BD with RO, FO, and CA; group IV-BD with RO, FO, CA, and SeY; group V-BD with RO, FO, CA, and SeVI. The diets with Se compounds increased Se concentrations in all tissues compared with other diets. The diet with SeVI increased Cd, Sb, and Pb concentrations in the liver compared to groups I, II, and IV. The diets containing Se compounds increased Sb and Pb concentrations in MBF compared to groups I and II. All diets with CA reduced As, Sb, and Pb concentrations in MLD compared to groups I and II. All diets with FO increased concentrations of FAs and malondialdehyde in the liver compared to group I. All diets with FO decreased FAs concentrations in MBF compared to group I. The diets containing CA with/without Se compounds increased malondialdehyde concentrations in MBF compared to groups I and II. The diet with Se compounds reduced malondialdehyde concentrations in MLD compared to group II. All diets with FO changed concentrations of tocopherols and cholesterol in all tissues compared to group I. Our study showed that the addition of SeY or SeVI to the experimental diet increased the concentration of Se in all assayed tissues of lambs without adversely influencing performance or causing physiological disorders in internal organs. Both, SeY or SeVI added to the experimental diet decreased the oxidative stress and the concentrations of As, Sb, and Pb in MLD compared with the diets containing RO, irrespective of the presence of FO (groups I and II). Our study provides useful knowledge for nutritionists carrying out further investigations aimed at improving farm animal health, performance, and the nutritional quality of animal products for humans.