Pharmacokinetics of dexamethasone after intravenous and intramuscular administration in broiler chickens

The aim of this study was to determine the pharmacokinetics of dexamethasone in broiler chickens. Dexamethasone sodium phosphate (0.3 mg/kg bodyweight) was injected IV or IM and blood samples were collected at 0, 0.25, 0.5, 0.75, 1, 2, 4, 6, 8, 10, 12 and 24 h after administration. Dexamethasone in the plasma samples was measured using a liquid chromatography–tandem mass spectrometry method and the pharmacokinetics analysed according to a one-compartmental model.The maximum plasma concentration after IM administration occurred at 0.37 h. The elimination half-life for dexamethasone was 0.46 h and 0.70 h following IV and IM administration, respectively, which was shorter than other species, while the clearance (1.26 L/h kg) was higher than has been reported for other species (<0.5 L/h kg). The volume of distribution (～1 L/kg) was similar to values reported for other species and the bioavailability of dexamethasone after IM administration was 100%. The results from this study will be useful in investigating whether inflammatory disease may affect the pharmacokinetic parameters of dexamethasone in chickens.     

Advances in Variable Rate Technology Application in Potato in The Netherlands

Precision agriculture is a farming management concept based on observing, measuring and responding to inter- and intra-field variability in crops. In this paper, we focus on responding to intra-field variability in potato crops and analyse variable rate applications (VRAs). We made an overview of potential VRAs in potato crop management in The Netherlands. We identified 13 potential VRAs in potato, ranging from soil tillage to planting to crop care to selective harvest. We ranked them on availability of ‘proof of concept’ and on-farm test results. For five VRAs, we found test results allowing to make a cost-benefit assessment. These five VRAs were as follows: planting, soil herbicide weed control, N side dress, late blight control and haulm killing. They use one of two types of spatial data: soil maps or biomass index maps. Data on costs and savings of the VRAs showed that the investments in VRAs will pay off under practical conditions in The Netherlands. Savings on pesticide use and N-fertilizer use with the VRAs were on average about 25%, which benefits the environment too. We foresee a slow but gradual adoption of VRAs in potato production. More VRAs will become available given ongoing R&D. The perspectives of VRAs in potatoes are discussed.     

Hydrolysed salmon meal as a replacement for salmon meal in practical diets for Pacific white shrimp (Litopenaeus vannamei)

A series of growth, feed stability and consumption trials were conducted to evaluate the efficacy of salmon by‐product in practical diets for Pacific white shrimp, Litopenaeus vannamei. This included a salmon by‐product meal (Salmon meal: SM) and a silage hydrolysate (hydrolysed salmon meal: HSM). The basal diet containing 120 g/kg SM was incrementally replaced (0. 25, 50, 75, 100%) by HSM to produce five test diets used in two trials. A sixth diet was included which evaluated gelatin supplementation (trial 1) or pH neutralization (trial 2). In trial 1, each diet was produced using two processing conditions (laboratory extruded and formed with meat grinder) and offered to shrimp in a clear water system. The results demonstrate that up to 50% of the SM can be used to replace with HSM; however, further increases resulted in reduced performance of shrimp. The addition of gelatin reduced leaching but there was limited effect of processing on leaching. There were no detectible effects of pH adjustment of the diets. Results indicated that the growth performance of shrimp has not influenced by HSM up to 60 g/kg to replace 50% of the SM in practical diets; however, higher levels resulted in significant decrease in performance.     

Genetic characterization of <Emphasis Type="Italic">Pepino mosaic virus</Emphasis> isolates from Belgian greenhouse tomatoes reveals genetic recombination

Over a period of a few years, Pepino mosaic virus (PepMV) has become one of the most important viral diseases in tomato production worldwide. Infection by PepMV can cause a broad range of symptoms on tomato plants, often leading to significant financial losses. At present, five PepMV genotypes (EU, LP, CH2, US1 and US2) have been described, three of which (EU, LP and US2) have been reported in Europe. Thus far, no correlation has been found between different PepMV genotypes and the symptoms expressed in infected plants. In this paper, the genetic diversity of the PepMV population in Belgian greenhouses is studied and related to symptom development in tomato crops. A novel assay based on restriction fragment length polymorphism (RFLP) was developed to discriminate between the different PepMV genotypes. Both RFLP and sequence analysis revealed the occurrence of two genotypes, the EU genotype and the CH2 genotype, within tomato production in Belgium. Whereas no differences were observed in symptom expression between plants infected by one of the two genotypes, co-infection with both genotypes resulted in more severe PepMV symptoms. Furthermore, our study revealed that PepMV recombinants frequently occur in mixed infections under natural conditions. This may possibly result in the generation of viral variants with increased aggressiveness.     

Use of salmon by‐product meals as a replacement for anchovy meal in practical diets for the Pacific white shrimp (Litopenaeus vannamei)

A series of trials were conducted with Pacific white shrimp Litopenaeus vannamei, to evaluate the efficiency of two salmon meals as compared to anchovy meal. The basal diet contained 200 g/kg anchovy meal, which was systematically replaced (0%, 50%, 75% and 100%) with salmon meal on an isonitrogenous basis. Another two diets were formulated with a hydrolysed salmon meal to replace 50% and 100% anchovy meal. Each diet was randomly fed to four replicate groups of 25 and 30 shrimp per tank in clear (indoor) and green (outdoor) water trials, respectively. The results showed that growth performance and feed conversion ratio were not statistically different when salmon meal replaced anchovy meal in both trials. However, when hydrolysed salmon meal was used to replace 100% of the anchovy meal, growth performance of the shrimp significantly decreased. The four kinds of fish meal (anchovy, salmon by‐product meals and menhaden) were evaluated in an ingredient digestibility trial using the 70:30 replacement technique. In general, dry matter, energy, protein and individual amino acids digestibility of salmon meal were significantly higher than those of menhaden and anchovy meal. Results of this study demonstrated that salmon meals are a good protein sources which can replace anchovy meal.     

Wheat (Triticum aestivum L.) puroindoline functionality in bread making and its impact on bread quality

Wheat puroindolines (PINs) spontaneously adsorb at air/water interfaces and show excellent foaming properties. They can positively impact bread quality, in which the formation of stable foam is important for product quality. The impact of endogenous PINs on bread quality was studied by preparing gluten–starch blends from isolated gluten and starch fractions with different PIN levels, which allowed largely retaining the interaction between PINs and flour components. Our results indicate that blends with high PIN levels yielded more homogeneous crumb structures with fine gas cells than bread made with blends containing medium or low PIN levels. However, the mechanism by which PINs exert this crumb improving effect is not clear. Varying PIN levels impacted neither dough extensibility nor did it result in different PIN levels in dough liquor. Lipid removal yielded bread with a less homogeneous crumb gas cell distribution, indicating that lipids also are required to obtain good crumb structure.     

Starch isolation method impacts soft wheat (Triticum aestivum L. cv. Claire) starch puroindoline and lipid levels as well as its functional properties

Wheat (Triticum aestivum L.) kernel hardness is a major quality characteristic, which has been ascribed to the presence of puroindolines a and b. These proteins occur in higher levels at the surface of water-washed starch granules from soft wheat cultivars than at that of starch from hard wheat cultivars. In the present study, prime starch was isolated from flour from soft wheat (cultivar Claire) using a dough ball or batter based separation method. Starch isolated with the dough ball method contained lower levels of puroindolines, as well as of other starch granule associated proteins and lipids than that isolated with the batter method. Similar patterns of puroindoline and lipid levels after starch isolation can presumably be related to (polar) lipid binding by puroindolines. Both isolated starch fractions showed comparable differential scanning calorimetry thermograms, whereas higher levels of starch surface associated components restricted starch swelling. Necessary controls demonstrated that the observed differences did not arise from artefacts associated with hydration, fractionation or freeze-drying in the experimental protocols. Apparently, proteins and lipids at the starch granule surface impact water absorption and, as such, starch swelling, but they do not affect starch granule internal phenomena such as melting of the crystalline amylopectin chains.