Nitrification along a grassland gradient: Inhibition found in matgrass swards

Measurements along a hill-slope vegetation gradient in nutrient-poor grasslands from acid grasslands via matgrass swards to calcareous grasslands showed increased ammonium to nitrate ratios in the matgrass swards. These results generated the research question whether there might be a difference in nitrification activity or nitrifying community composition between the different zones in this hill-slope gradient. In each of the vegetation types along the gradient, soil samples were taken in five grassland nature reserves. Potential nitrification rates have been determined as an indication of the size of the active ammonia-oxidising microbial communities. Additionally, the dominant ammonia-oxidising sequences related to the β-Proteobacteria have been determined by a Polymerase Chain Reaction (PCR) based on the 16S rRNA gene in combination with Denaturing Gradient Gel Electrophoresis (DGGE) at one of the nature reserves.Compared to the top and lower zones of the vegetation gradient (i.e. acid grasslands and calcareous grasslands, respectively), potential nitrification rates were clearly repressed in the middle, matgrass swards zone. In contrast to the differences in potential nitrification activities observed in one of the nature reserves (Bemelerberg), no differences in dominant ammonia-oxidising sequences were observed at this location. One sequence belonging to cluster 3 of the Nitrosospira lineage appeared to be dominant among the sequences belonging to the ammonia-oxidising species of the β-Proteobacteria in all vegetation zones. Nitrification was apparently inhibited by the vegetation, whereas no shift in nitrifier populations could be shown. The possible role of repressed nitrification in the decline of this vegetation type is discussed.     

Increasing soy isoflavonoid content and diversity by simultaneous malting and challenging by a fungus to modulate estrogenicity

Soybeans were germinated on a kilogram-scale, by the application of malting technology used in the brewing industry, and concomitantly challenged with Rhizopus microsporus var. oryzae. In a time-course experiment, samples were taken every 24 h for 10 days, and the isoflavonoid profile was analyzed by RP-UHPLC-MS. Upon induction with R. microsporus, the isoflavonoid composition changed drastically with the formation of phytoalexins belonging to the subclasses of the pterocarpans and coumestans and by prenylation of the various isoflavonoids. The pterocarpan content stabilized at 2.24 mg of daidzein equivalents (DE) per g after ～9 days. The levels of the less common glyceofuran, glyceollin IV, and V/VI ranged from 0.18 to 0.35 mg DE/g and were comparable to those of the more commonly reported glyceollins I, II, and III (0.22-0.32 mg DE/g) and glycinol (0.42 mg DE/g). The content of prenylated isoflavones after the induction process was 0.30 mg DE/g. The total isoflavonoid content increased by a factor of 10-12 on DW basis after 9 days, which was suggested to be ascribable to de novo synthesis. These changes were accompanied by a gradual increase in agonistic activity of the extracts toward both the estrogen receptor α (ERα) and ERβ during the 10-day induction, with a more pronounced activity toward ERβ. Thus, the induction process yielded a completely different spectrum of isoflavonoids, with a much higher bioactivity toward the estrogen receptors. This, together with the over 10-fold increase in potential bioactives, offers promising perspectives for producing more, novel, and higher potency nutraceuticals by malting under stressed conditions.     

Validation of a disease model in Japanese quail (Coturnix coturnix japonica) with the use of Escherichia coli serogroup O2 isolated from a turkey

This study established a disease model and protocol for bacterial challenge with Escherichia coli serogroup O2 strain EC317 in Japanese quail. Five groups of 10 birds each were injected subcutaneously in the breast with 200 μL of a brain-heart infusion (BHI) culture containing 1 × 10(8), 1 × 10(7), 1 × 10(6), 1 × 10(5), or 1 × 10(4) colony-forming units/mL of the test organism, which had been isolated from a turkey with cellulitis and septicemia. Birds in a 6th group were controls that received sterile BHI alone. Localized lesions of cellulitis developed in all of the birds that received E. coli. The morbidity and mortality rates were highest (100%) in the birds receiving the highest dose of E. coli and decreased linearly with decreasing dose (P < 0.05). Severity of disease, including lesions of pericarditis and perihepatitis, was also directly proportional to the dose of E. coli. These findings indicate that this disease challenge protocol can be used to study disease resistance and immunologic consequences of contaminant exposure or other stressors in birds.     

Sow litter size is increased in the subsequent parity when lactating sows are fed diets containing n-3 fatty acids from fish oil

Supplementing diets with n-3 fatty acids from fish oil has been shown to improve reproductive performance in dairy cattle and sheep, but there is little published literature on its effects in sows. The aim of this study was to evaluate the reproductive performance of sows fed fish oil as a source of n-3 PUFA prefarrowing and during lactation. From d 107.7 ± 0.1 of pregnancy, 328 sows ranging in parity from 0 to 7 (parity 1.95 ± 0.09, mean ± SE) were fed either a diet containing tallow (control) or an isocaloric diet containing 3 g of fish oil/kg of diet (n-3). Diets were formulated to contain the same amount of DE (13.9 MJ/kg), crude fat (54 g/kg), and CP (174 g/kg). Sows were fed their treatment diet at 3 kg daily for 8 d before farrowing and continued on treatment diets ad libitum until weaning at 18.7 ± 0.1 d of lactation. After weaning, all sows were fed a gestation diet without fish oil until their subsequent farrowing. There was no effect (P > 0.310) of feeding n-3 diets prefarrowing on piglet birth weight, preweaning growth rate, piglet weaning weight, or sow feed intake. However, n-3 sows had a larger subsequent litter size (10.7 ± 0.3 vs. 9.7 ± 0.3 total born; 10.2 ± 0.3 vs. 9.3 ± 0.3 born live; P < 0.05). In conclusion, this is the first study to demonstrate that feeding sows a diet containing n-3 PUFA from fish oil fed before farrowing and during lactation increased litter size in the subsequent parity independent of energy intake.     

Design, Construction, and Testing of an Automated NIR In-line Analysis System for Potatoes. Part II. Development and Testing of the Automated Semi-industrial System with In-line NIR for the Characterization of Potatoes

An automated semi-industrial system with in-line near-infrared reflectance (NIR) for the characterization of the chemical composition of potatoes was designed and constructed, and its performance was tested. The system consisted of the following subsystems: sample crate manipulator, weighing unit for the gross sample weight, potato washing machines with a washing water recycling system, belt for visual inspection of the potatoes, unit for measuring the underwater weight (UWW), industrial rotary saw blade rasp for pulping the potatoes equipped with a sulfite dosage system for inhibiting enzymatic browning of the pulped potatoes, and industrial NIR system for the measurement of the potato composition. The whole system was controlled and operated by a programmable logic controller and process personal computer system. The system was able to process 12 potato samples per hour. Measurements were done to establish the sample carry-over in the system. The carry-over was proven to be well below the maximum acceptable level of 2%. The UWW values established with the automatic system corresponded very well with the UWW data obtained by manual weighting. The day-to-day reproducibility of the UWW system was tested with golf balls. These balls have about the same specific gravity and size as potatoes. The day-to-day reproducibility coefficient of variation of the UWW unit was 0.4%. As a principle of proof, two tentative partial least squares calibration models, one for the starch concentration and one for the coagulating protein concentration in the potato samples, were calculated, applying leaving one out cross-validation. Both models were very promising. The by NIR-predicted starch concentrations showed to be at least as good or even better than the by UWW-obtained starch concentrations. The average difference between the by NIR-predicted and the chemically measured starch concentration was 0.0 ± 0.3% (w/w). For the coagulating protein concentration, the average difference between the by NIR-predicted and the chemically measured concentration was 0.00 ± 0.06% (w/w). In future years, potatoes of a wider range of varieties, growing locations, and growing seasons have to be added to the present tentative model, in order to get a robust NIR model.     

Diagnosis of bovine spongiform encephalopathy: A review

Summary

Cows affected with bovine spongiform encephalopathy (BSE) display chronic neurological signs consisting of behavioural changes, abnormalities of posture and movement, and/or hyperaesthesia. At present, there are no laboratory test available to diagnose BSE in the live animal. In this article, we describe the post‐mortem diagnostic examination of brains from BSE‐suspected cattle as currently performed at ID‐Lelystad. The routine laboratory diagnosis of BSE consists of histopathological examination of the brain and detection of the modified prion protein, PrP^BSE, in brain tissue. These tests, however, have the disadvantage of being laborious and time consuming, so that results are available only after several days.

Recently, at ID‐Lelystad a new post‐mortem test has been developed that enables screening of larger volumes of brain samples for PrP^BSE within 1 day. This BSE test is especially suited for slaughterline monitoring. A preliminary validation study has shown that both sensitivity and specificity are 100% compared to the gold diagnostic standard of histopathology.