Einige Beobachtungen über Hausbock

Ohne Zusammenfassung Mit 9 Abbildungen.     

Nitrogen fluxes during the initial stage of willows and poplars in short‐rotation coppices

Among energy crops, short‐rotation coppices (SRC) are recommended to provide renewable energy. Compared to annual crops, willows and poplars are regarded as plants with low requirements for nutrients, herbicides, pesticides, and soil maintenance. However, only little is known about N‐fertilizer effects on SRC and the few studies are even inconsistent. Therefore, we studied the effects of N on yields of willows and poplars in a field experiment. The effects of N fertilization on nitrate leaching and nitrous oxide emissions from the loamy‐sand soil were also measured. Cuttings of willows (Salix viminalis clone Inger) and poplars (Populus maximovizcii × P. nigra clone max 4) were planted on farmland in 2008. The experiment was arranged in a random block design with three levels of N fertilizer (0, 50, and 75 kg N ha^–1 y^–1). After 2 y, the trees were harvested for the first time. Fertilization did not affect the yields of willows or poplars. However, the application of 75 kg N ha^–1 y^–1 caused an average increase of N leaching in the willow and poplar plots of 25 kg N ha^–1 y^–1 and 40 kg N ha^–1 y^–1, respectively. Emissions of N₂O were increased by a maximum of only 0.2 kg N ha^–1 y^–1. Further, the N fertilizer stimulated the growth of the weed biomass in case of the willow plots by 46% and of the weed N content by 52% (r = 0.53). In conclusion, in the first 2 y, SRC could be produced in a more effective and environmentally friendly manner without mineral fertilizer.     

Das Holz der Roteiche

Zusammenfassung Das kanadische Roteichenholz ift bei gleichem Darrgewicht (0,65) und nur wenig gröszerer Jahrringbreite (2,5 gegen 2,3 mm) hinsichtlich der Festigteitswerte dem Holz aus dem südlichen Teil des natürlichen Berbreitungsgebietes in den Bereinigten Staaten überlegen.Das bedeutend schwerere Weiszeichenholz aus dem füdlichen Teil des Berbreitungsgebietes in den Bereinigten Staaten ist dem Roteichenholz dieses Gebietes (0,71 gegen 0,65 Darrgewicht) in den Festigkeitswerten (bis aus das Biegedehnmasz und Biegearbeit) und den Gütewerten ein wenig überlegen. Die Jahrringbreiten find allerdings stark verschieden (1,5 gegen 2,3 mm), wobei die Spätholzanteile nur unwesentlich voneinander abweichen. Die kanadischen Proben zeigen eine geringe überlegenheit des Roteichenholzes gegenüber jenem der Weiszeiche hinsichtlich der Festigkeits- und Gütewerte, wobei die Iahrringbreiten stark verschieden sind (2,5 mm und 0,65 gegen 1,3 mm nnd 0,77). Die älteren amerikanischen Untersuchungen bestätigen, dasz das Roteichenholz trotz geringeren Gewichtes (0,65 gegen 0,75) hinsichtlich Festigkeit und Biegedehnmasz überlegen ist.Das Holz der heimischen Traubeneiche ist dem amerikanischen Weiszeichenholz aus dem Süden der Bereinigten Staaten bei gleichem Darrgewicht 0,71 und nur wenig abweichender Iahrringbreite (1,6 gegen 1,5 mm) bis aus das Biegedehnmasz überlegen. Das Roteichenholz aus den Bereinigten Staaten zeigt gegenüber dem Traubeneichenholz (0,65 gegen 0,71) in den Festigkeits-werten, Berhältniszahlen und Gütewerten eine Unterlegenheit. Am geringsten ist dieselbe beim Biegetragmasz, am groszen bei der Drucksestigkeit, im Durchschnitt um etwa 20%. Auch das kanadische Roteichenholz ist dem Traubeneichenholz unterlegen.In Deutschland erwachsenes Roteichenholz steht dem in Nordamerika ervachfenen kaum nach. Die Berwendung des Roteichenholzes ist ähnlich jener des Weisz- und Traubeneichenholzes in Nordamerika und Europa. Hinsichtlich der Dauer und Berwendbarkeit zu Fässern mit alkoholischer Flüssigkeit stehn es den genannten Arten nach.     

Juvenile cobia (Rachycentron canadum) can utilize a wide range of protein and lipid levels without impacts on production characteristics

Two, 6 week feeding trials were conducted to evaluate the impacts of protein and lipid on weight gain, feed efficiency ratio values and biological indices of juvenile cobia (Rachycentron canadum). Utilizing a 2 × 3 factorial design, experimental diets containing two levels of crude protein (CP; 40 and 50%) and three levels of lipid (6, 12 and 18%), providing 14.4, 15.1 and 16.6 kJ available energy/g dry diet (calculated), respectively, were formulated for use in both feeding trials. In the first trial, cobia (initial weight 49.3 g per fish) was randomly assigned to one of the six experimental diets and fed to apparent satiation twice daily. At the end of the first trial, weight gain in cobia was not significantly impacted by protein levels with values ranging from 333% (50% CP) to 353% (40% CP). However, lipid significantly (P < 0.05) affected weight gain with fish fed the diet containing 18% total lipid returning the lowest growth of 293%. Feed efficiency ratio values were not significantly impacted by dietary protein or lipid levels and ranged from 0.46 (50% CP/18% lipid) to 0.51 (50% CP/6 and 12% lipid). Survival was significantly impacted by protein and lipid with fish fed the diets containing 50% CP and 18% lipid having lower (P < 0.05) survival rates of 90%.In the second trial, smaller fish were utilized (7.4 g average initial weight) under identical experimental conditions and dietary formulations. Weight gain was not significantly affected by protein or lipid levels and ranged from 1099% in fish fed the diet containing 40% CP/18% lipid to 1305% in fish fed the diet containing 50% CP/12% lipid. Feed efficiency ratio values, visceral somatic and hepatosomatic indices were significantly affected by protein and/or lipid. Muscle and liver lipid were impacted by dietary lipid (P = 0.0203 and 0.0012, respectively). Muscle protein was significantly impacted by dietary protein levels, while liver protein was affected by both main effects. Dietary protein and lipid had no impact on muscle ash.These data suggest that juvenile cobia can thrive on a wide range of protein and lipid levels, as well as a range of protein to energy ratios. Positive impacts of optimizing the protein component in terms of economic and environmental concerns, coupled with the ability to maintain the rapid growth rates this species are renowned for at lower dietary lipid levels, point towards beneficial consequences of further refinement of commercial cobia production feeds.     

Influence of a rumen-protected conjugated linoleic acid mixture on carcass traits and meat quality in young Simmental heifers

The aim of the present study was to investigate the influence of feeding rumen-protected CLA during the early growing period on physical and chemical beef properties in young Simmental heifers. A total of 36 heifers (5 mo old; initial BW 185 ± 21 kg) were fed 250 g of different rumen-protected fats daily for 16 wk in 1 of 3 treatment groups: 250 g of a CLA-free control fat; 100 g of a CLA fat containing 2.4% of cis-9,trans-11 CLA and 2.1% of trans-10,cis-12 CLA and 150 g control fat; or 250 g of the CLA fat. Heifer growth performance variables as well as carcass weight, classification (conformation and fatness), and weights of organs and fat depots were not affected (P > 0.05) by CLA supplementation. Concentration of trans-10,cis-12 CLA in tissues (LM and subcutaneous fat) was dose-dependently increased (P < 0.01) by CLA supplementation, whereas that of cis-9,trans-11 CLA in these tissues did not differ (P > 0.05) between groups. The ratio of SFA to MUFA was increased (P < 0.01) in tissues of CLA-fed heifers compared with control heifers. Concentration of α-tocopherol in LM was greater (P = 0.01) in heifers of the 2 CLA groups than in control heifers. Other quality characteristics such as drip loss during storage, cooking loss, intramuscular fat content, and color variables in LM did not differ (P > 0.05) between groups. In conclusion, the present study demonstrates that feeding rumen-protected CLA during the early growing period changes tissue fatty acid composition but does not influence beef quality variables. Performance variables and carcass traits in young heifers, unlike in pigs and laboratory animals, are not influenced by CLA feeding.     

Concentrations of retinol and tocopherols in the milk of cows supplemented with conjugated linoleic acid

This study was performed to investigate the hypothesis that supplementation of conjugated linoleic acid (CLA) changes the concentrations of retinol and tocopherols in the milk of cows. To investigate this hypothesis, Holstein cows received daily from 3 weeks ante‐partum to 14 weeks post‐partum either 172 g of a CLA‐free rumen‐protected control fat (control group, n = 20) or the same amount of a rumen‐protected CLA fat, supplying 4.3 g of cis‐9, trans‐11 CLA and 3.8 g of trans‐10, cis‐12 CLA per d (CLA group, n = 20). Milk samples (collected at weeks 1, 3, 5, 8 and 11 of lactation) were analysed for retinol, α‐ and γ‐tocopherol concentrations. Milk of cows supplemented with CLA had higher concentrations of retinol (+34%), α‐tocopherol (+44%) and γ‐tocopherol (+21%) than milk of control cows (p < 0.05). The daily output of these vitamins via milk was also greater in cows of the CLA group than in cows of the control group (+36, 50 and 24% for retinol, α‐tocopherol and γ‐tocopherol, respectively, p < 0.05). In agreement with higher concentrations of tocopherols, concentrations of thiobarbituric acid‐reactive substances, determined in milk of week 5, were lower in cows of the CLA group than in control cows, indicative of a lower susceptibility of milk lipids to peroxidation. Plasma concentrations of retinol and α‐tocopherol, determined at 1 and 5 weeks post‐partum, were not different between the two groups of cows. In conclusion, this study shows that supplementing dairy cows with a moderate amount of CLA causes an increase of the concentrations of vitamins A and E in the milk and results in an increased output of those vitamins via milk. These effects might be beneficial with respect to the nutritional value of dairy products and the susceptibility of milk fat to oxidative deterioration.     

Partitioning of selected antioxidants in mayonnaise.

This study examined partitioning of alpha-, beta-, and gamma-tocopherol and six polar antioxidants (Trolox, ferulic acid, caffeic acid, propyl gallate, gallic acid, and catechin) in mayonnaise. Partitioning of antioxidants between different phases was determined after separation of mayonnaise by either (a) centrifugation + ultracentrifugation or (b) centrifugation + dialysis. Antioxidants partitioned in accordance with their chemical structure and polarity: Tocopherols were concentrated in the oil phase (93-96%), while the proportion of polar antioxidants in the oil phase ranged from 0% (gallic acid and catechin) to 83% (Trolox). Accordingly, proportions of 6% (Trolox) to 80% (gallic acid and catechin) were found in the aqueous phase. Similar trends were observed after dialysis. After ultracentrifugation, large proportions of polar antioxidants were found in the "emulsion phase" and the "precipitate" (7-34% and 2-7%, respectively). This indicated entrapment of antioxidants at the oil-water interface in mayonnaise. The results signify that antioxidants partitioning into different phases of real food emulsions may vary widely.     

Preparation and comparative release characteristics of three anthocyanin encapsulation systems

Bilberries (Vaccinium myrtillus L.) and their major polyphenolic constituents, anthocyanins, have preventive activities inter alia against colon cancer and inflammatory bowel diseases. However, anthocyanins are sensitive to environmental conditions; thus their bioavailability in the gastrointestinal tract is an important determinant of their in vivo activity. In the study reported here, the potential benefits of encapsulating an anthocyanin rich bilberry extract (BE) on anthocyanin stability were investigated. Nonencapsulated BE and three different BE loaded microcapsule systems were incubated in simulated gastric fluid (SGF) and fed state simulated intestinal fluid (FeSSIF). After exposure to these media, released anthocyanins were identified and quantified by HPLC with UV/Vis detection. Although a rapid release of anthocyanins was observed within the first 20 min, encapsulation of anthocyanins doubled the amount of available anthocyanins after 150 min of incubation. These results illustrate the ability of encapsulation to inhibit early degradation of anthocyanins in the intestinal system.