Einfluss der Grünlandnutzung auf die PPO-Aktivität in Rotklee

Several studies show that polyphenol oxidase (PPO) in red clover reduces proteolysis and increases nitrogen use efficiency of the ruminant, but not much is known about factors affecting PPO activity in red clover plants. PPO activity was analysed in red clover plants from legume-grass mixtures subjected to three different management systems. The cutting frequency (3 or 5 cuts) caused only minor differences in PPO activity, whereas a significant increase in PPO activity could be proved for the rota-tional grazing system (RG), compared to the simulated grazing system (SG, 5 cuts) with equal use frequency. Results indicate a metabolic adaptation of the red clover plants due to the grazing process itself, leading to a control factor which has to be considered in case of red clover nutrition properties

Auswirkungen von Schnitt-und Weidenutzung auf die Ertragsbildung und den Stickstoffgehalt verschiedener Futterleguminosen.

The objective of this study was to compare the agronomic performance of different forage legume species submitted to different management systems, i.e. grazing, silage-cut and simulated grazing to find alternatives for white clover. The experiment was established in 2003 and 2004 as binary swards with perennial ryegrass (Lolium perenne L.) as the companion grass with three replicates in two different sites on the experimental station “Lindhof” of the University of Kiel. Legume species were arranged within each management system as completely randomised blocks. Results of agro-nomic performance of the first production years in 2004 and 2005 (DM-yield, botanical composition, N-yield, N-content) are presented for white clover swards (Trifolium repens L.), red clover swards (Trifolium pratense L.), lucerne swards (grazing type, Medicago sativa L.) and birdsfoot trefoil swards (Lotus corniculatus L.). Considering both years the birdsfoot trefoil/grass-swards were the only ones which produced significantly less DM-yield (736 g DM m² a-1) under simulated grazing than the white clover/grass-swards (805 g DM m2 a-1). While under grazing all legume/grass-swards produced a significant lower DM-yield compared to the white clover/grass-swards, no significant differences can be found under the silage-cut system. Considering the N-yield, birdsfoot trefoil/grass-swards were the only legume/grass-swards which pro-duced a significant lower N-yield under the 5-cut system (14.1 g N m² a-1) as well as under grazing (15.7 g N m² a-1) compared to the white clover/grass-swards (26 g N m² a-1 and 21.9 g N m² a-1 respectively). Considering the botanical composition of the different legume/grass-swards all legume species had a significant higher propor-tion of total DM-yield under cutting compared to white clover in 2004. Comparisons between systems showed that beside the white clover/grass-swards all legume/grass-swards had a significant lower legume proportion under grazing in comparison to the cutting systems. Because of the comparable agronomic performance of the red clo-ver/grass-swards and lucerne/grass-swards, both legume species could be used as alternatives for white clover under cutting, while the birdsfoot trefoil/grass-swards should be considered carefully because of their low agronomic performance. Whereas white clover showed the highest performance under the grazing system, none of the different legume species present an alternative for white clover

Proteinqualität verschiedener Rotkleegenotypen unter Berücksichtigung der spezifischen Polyphenoloxidase-Aktivität

Increasing protein quality of forages in ruminant nutrition may contribute to reduce nitrogen losses in specialized dairy farms in Europe. Red clover is known to have high polyphenol oxidase (PPO) activity among forage legumes. The enzyme oxidizes phenols to quinones. These highly reactive quinones form stabilized quinone-protein-complexes, protecting protein from fast degradation. The objective of this study was to investigate the effect of the specific PPO activity on the protein fractions of twelve red clover genotypes in two management systems (without and with mechanical stress) in pure red clover swards. The results showed that genotype seem to be of minor importance compared to the variation in PPO activity induced by mechanical stress and particular by cut. Furthermore, with increasing specific PPO activity fraction A decreased and fraction C increased slightly. However, specific PPO activity was poorly related to the protein fractions, expressed by a low R²

Genotypbedingte Veränderungen der Proteinqualität bei der Gärfutterbereitung von Rotklee

Ensilage of red clover results in lower concentrations of non-protein nitrogen compared to other forage legumes. It is assumed that the polyphenol oxidase (PPO) activity in red clover is related to this effect. Therefore, a laboratory ensiling trial was carried out to quantify the changes in crude protein (CP) fractions during the ensiling process using the Cornell Net Carbohydrate and Protein System. At four cutting dates, fresh, wilted and ensiled herbage of three red clover genotypes and white clover grown in two systems (with and without mechanical stress) was sampled. The specific PPO activity was measured photometrically in fresh leaves of the plants. Concentrations of fraction A increased from 130-197 g/kg CP to 372-544 g/kg CP during the fermentation process leading to a drop in true protein, primarily fraction B1. The most important source of variance was the ensiling stage, except for fraction C. Despite of differences in protein fractions between genotypes, these variations can not be explained by the specific PPO activity

Mapping Conceptual Understanding of Experts, Teachers, and Students through Conceptual Metaphor Theory

This study investigates conceptual understanding of quantum physics across expertise levels using conceptual metaphor theory. Interviews and focus groups with experts, teachers, and students revealed distinct metaphorical patterns. Experts exhibited complex, interconnected metaphors, while novices displayed fragmented and limited mappings. These findings demonstrate the role of metaphor in making meaning of abstract scientific concepts and offer insights into the development of expertise in quantum physics. By understanding the role of conceptual metaphors in learning and reasoning, we can develop more effective pedagogical approaches that foster deeper understanding and critical thinking skills

Variation in Protein Quality of Forage Legumes During Spring Growth

The utilisation of forage legumes in combination with reduced N inputs as fertilisers is an alternative for the production of high quality forage. Although white clover (WC) is widely used in grassland and has a high content of crude protein (CP), a combination of this high CP content with a high proportion of rapidly-available proteins and fast degradation rate in the rumen may reduce the efficiency of N use by ruminants in comparison with other forage legumes. The objective of the present study was to investigate the variation in content of CP fractions A, B and C in different forage legume during the spring growth in comparison with WC

Da guerrilha à imprensa feminista

Da guerrilha à imprensa feminista: a construção do feminismo pós-luta armada no Brasil (1975-1980)” é um livro de muita atualidade, considerando o panorama político no qual o Brasil se encontra no momento, com o afastamento da presidenta Dilma Rousseff, eleita democraticamente, e a assunção de um governo interino, pelas vias de um impeachment questionável. Este, sem dúvida, é um aspecto injusto, sexista e misógino na e da política brasileira, faces de um poder elitista, individualista e economicista