Dietary strategies for reduced phosphorus excretion and improved water quality

Cost effective feeding strategies are essential to deal with P surpluses associated with intensive animal agriculture and the consequent impact on water quality. Reduction of P overfeeding, use of feed additives to enhance dietary P utilization, and development of high available phosphorus (HAP) grains have all been shown to decrease fecal P excretion without impairing animal performance. Much progress has been made, but more research will be needed to refine these strategies to maximize reductions in P excretion while maintaining animal performance. Recent research has focused on the impact of modifying dietary P on the forms of P excreted and the mobility of P in soils amended with these manures, with strong treatment trends becoming evident in the literature. In general, dietary strategies have been developed that can effectively reduce the total P concentration in manures produced, and combining strategies usually leads to greater reductions than individual practices. However, the impact of different approaches on the solubility of P in manures and amended soils has been more variable. Soluble P remains of particular concern due to links between solubility of P in manure and P losses from manure-amended soils. In this paper, we outline the major strategies for reducing dietary P in different species, review the literature on the impact of these approaches on P forms in manures and amended soils, and discuss the potential beneficial effects on animal agriculture and the environment.     

Teilchenspuren in der Mikrotechnik

Wir danken M. Chlupka-Spohr, R. Handel, Chr. Trautmann und J. Vetter für wertvolle Anregungen zu diesem Bericht.     

An approach to environmental assessment within the land‐use planning process: Northern Spanish experiences

The problems involved in environmental assessment of land‐use plans are discussed. A methodology is proposed for incorporating into the assessment of a plan the modifications that the physical environment would experience as a result of the plan's implementation. Thus, EIA can be integrated into the planning process. Impact assessment and comparison between alternative plans can be made using quantitative and qualitative indicators, some of which are proposed. Several case studies in northern Spain are used as the basis for the suggestions made.     

Field Deaths in Plant Agriculture

We know that animals are harmed in plant production. Unfortunately, though, we know very little about the scale of the problem. This matters for two reasons. First, we can’t decide how many resources to devote to the problem without a better sense of its scope. Second, this information shortage throws a wrench in arguments for veganism, since it’s always possible that a diet that contains animal products is complicit in fewer deaths than a diet that avoids them. In this paper, then, we have two aims: first, we want to collect and analyze all the available information about animal death associated with plant agriculture; second, we try to show just how difficult it’s to come up with a plausible estimate of how many animals are killed by plant agriculture, and not just because of a lack of empirical information. Additionally, we show that there are significant philosophical questions associated with interpreting the available data—questions such that different answers generate dramatically different estimates of the scope of the problem. Finally, we document current trends in plant agriculture that cause little or no collateral harm to animals, trends which suggest that field animal deaths are a historically contingent problem that in future may be reduced or eliminated altogether.     

Pheromonal regulation of starvation resistance in honey bee workers (<Emphasis Type="Italic">Apis mellifera</Emphasis>)

Most animals can modulate nutrient storage pathways according to changing environmental conditions, but in honey bees nutrient storage is also modulated according to changing behavioral tasks within a colony. Specifically, bees involved in brood care (nurses) have higher lipid stores in their abdominal fat bodies than forager bees. Pheromone communication plays an important role in regulating honey bee behavior and physiology. In particular, queen mandibular pheromone (QMP) slows the transition from nursing to foraging. We tested the effects of QMP exposure on starvation resistance, lipid storage, and gene expression in the fat bodies of worker bees. We found that indeed QMP-treated bees survived much longer compared to control bees when starved and also had higher lipid levels. Expression of vitellogenin RNA, which encodes a yolk protein that is found at higher levels in nurses than foragers, was also higher in the fat bodies of QMP-treated bees. No differences were observed in expression of genes involved in insulin signaling pathways, which are associated with nutrient storage and metabolism in a variety of species; thus, other mechanisms may be involved in increasing the lipid stores. These studies demonstrate that pheromone exposure can modify nutrient storage pathways and fat body gene expression in honey bees and suggest that chemical communication and social interactions play an important role in altering metabolic pathways.     

Bewertungsverfahren Verfahren zur Bewertung von immissionsbedingten Stoffanreicherungen in standardisierten Graskulturen

Standardized grass cultures are routinely used to evaluate the accumulation of air pollutants. For the assessment of air pollutant accumulation in grass cultures, it is particularly important to distinguish between “normal” concentrations and the significantly increased accumulation caused by air pollution. This article presents a method to determine “normal” element concentrations (background levels) and define threshold values for the significantly elevated accumulation of pollutants for individual series of grass cultures. By applying the same method for the data from six regional air quality measuring programs, it was possible to derive universally applicable “normal” concentrations and threshold values for grass cultures. The described method is not limited to the evaluation of data from grass cultures but is also suitable for other biological or ecological data. It allows to distinguish between “normal” element concentrations and unusually high or low concentrations.     

Cellular metabolism of arsenic studied in mammalian cellsin vitro

The cytotoxicity of trivalent and pentavalent inorganic arsenic was studied in cultured mouse fibroblasts. Concentrations of As(III) in the M range and approximately 10-fold higher concentrations of As(V) led to a reduction of cellular proliferation and viability with a concomitant increase of LDH release and stimulation of lactate production. Cells pretreated with a low As(III) concentration were less sensitive to toxic doses of As(III) or As(V).Uptake of As(III) by the cells was greater than that of As(V). Both forms of inorganic arsenic were converted intracellularly to monomethylarsonic (MMA) and dimethylarsinic (DMA) acids, which were subsequently released into the culture medium. In As-pretreated cells, which proved more resistant to As toxicity, biotransformation of inorganic to MMA and DMA was increased.