Dietary manipulation of the sow milk does not influence the lipid absorption capacity of the progeny

A control diet without supplemental fat and four diets containing 8% of coconut oil, rapeseed oil, fish oil or sunflower oil were fed to lactating sows in order to investigate the lipid absorption capacity of their progeny in terms of pancreatic enzyme activity, hormonal regulation, and bile salt concentration. In addition, the effect of age was studied during the four week suckling period, and during a three week postweaning period, in which a standard weaner diet was fed to all piglets. It is concluded that fat source and level in the maternal diet plays a minor role in comparison to piglet age with regard to lipid absorption capacity of the progeny postweaning.     

Plasma Cortisol and Behaviour in Early Weaned Piglets

Comparisons were made of Cortisol concentration and behavioural activity between piglets weaned at 3 weeks of age (early weaned piglets), and piglets weaned at 8 weeks of age (control piglets). Early weaned littermates were placed in cages with a floor area of either 0.20 m² per piglet or 0.15 m² per piglet. At 8 weeks of age, the piglets in the control litters were moved from the sow and early weaned piglets were moved from the cages. All litters were placed in pens, 1 pen for each litter. Radioimmunoassay was used for plasma Cortisol determination. Behavioural activity included determination of play, aggressive behaviour and non-nutritive oral activity. Statistical analysis for possible association between plasma Cortisol concentration and age, housing conditions, litter and sequence of capture of littermates for blood collection revealed a complex pattern. Generally, higher plasma Cortisol concentrations and more aggressive and non-nutritive oral activity, but less playing activity, were associated with early weaning. Plasma Cortisol concentration in individual piglets was positively correlated to both aggressive and non-nutritive oral behaviour, but was negatively correlated to playing behaviour. It is concluded that early weaning is a stressor.     

Interactions Between the Mycoparasite Pythium oligandrum and Sclerotia of the Plant Pathogen Sclerotinia sclerotiorum

Pythium oligandrum Drechsler is a mycoparasite which parasitizes hyphae of many fungal species. A detailed study of the interactions between P. oligandrum and the sclerotia of the plant pathogen Sclerotinia sclerotiorum (Lib.) de Bary is presented. Pythium oligandrum was present in Danish soils at concentrations between 4 and 26 cfu g^–1 soil. An increase in the natural population of P. oligandrum by addition of P. oligandrum zoospores to a soil reduced the ability of sclerotia of S. sclerotiorum to germinate myceliogenically and the sclerotia were colonized internally by P. oligandrum. This colonization and reduction of germination of sclerotia were also seen when sclerotia and P. oligandrum were incubated together in water. Small sclerotia were significantly more susceptible to parasitism by P. oligandrum than large sclerotia, and increasing the incubation time caused a further reduction in the germination ability of the sclerotia. P. oligandrum was able to pass through its entire life-cycle from zoospores to oogonia both with sclerotia as sole nutrient-source and in water containing exudates from the sclerotia. The cell wall degrading enzymes N-acetyl--D-glucosaminidase (NAGase), endo-chitinase, protease, -glucanase, -glucosidase and cellobiohydrolase were detected in culture filtrates of P. oligandrum cultivated with S. sclerotiorum. These findings suggest that P. oligandrum has a potential to reduce the survival of S. sclerotiorum sclerotia present naturally in soils, through mycoparasitic activity.     

Production performance of Atlantic salmon (Salmo salar L.) postsmolts in cyclic hypoxia,and following compensatory growth

This study investigated the production performance of the Atlantic salmon postsmolt (Salmo salar L.) subjected to cyclic oxygen reductions (hypoxia) of varying severity. Triplicate groups (N = 955) were kept at constant 80% O₂ (control) or subjected to 1 h and 45 min of hypoxia (50, 60 or 70% O₂, termed 80:70, 80:60 and 80:50 groups) every 6 h at 16°C for 69 days. Feed was provided in normoxia. One third of the fish were kept further for 30 days in normoxia to study possible compensatory growth. Cyclic hypoxia did not alter the oxygen uptake rates of fish, measured in night‐time. Fish subjected to 50% and 60% O₂ reduced feeding by 13% and 6% compared with the controls, respectively, with corresponding reductions in specific growth rates. Feed utilization was not reduced. Compensatory growth was observed in fish from the 80:50 group, but full compensation was not achieved. The main conclusions were that feeding in normoxia does not fully alleviate negative effects of cyclic hypoxia on feeding and growth, when oxygen is reduced to 60% or below in hypoxic periods, that feed utilization is maintained, and that compensatory growth may lessen negative effects.     

Effects of green manure storage and incorporation methods on nitrogen release and N2O emissions after soil application

More efficient use of green manure-derived nitrogen (N) may improve crop yields and reduce environmental impacts in stockless organic arable farming. In this 3-month incubation study, we tested a new strategy where green manure leys are harvested and preserved until the following spring either as compost mixed with straw or as silage of harvested ley biomass. Grass-clover compost or silage was soil-incorporated by either simulated ploughing (green manure placed at 15 cm depth) or harrowing (green manure mixed into the upper 5-cm soil horizon) in order to assess treatment effects on net release of plant-available N, nitrous oxide (N₂O) fluxes and soil respiration. Grass-clover silage provided the highest net N release with similar results for the two incorporation methods. Up to one third of the total N content in silage became plant-available during the 3 months. In contrast, no net N release was observed for the composted grass-clover and straw mixture. In fact, soil incorporation of compost by harrowing caused temporal immobilization of soil mineral N. Silage incorporated by ploughing gave rise to the largest N₂O effluxes with silage-induced emissions corresponding to 0.3 % of applied total N. Possibly N₂O production via denitrification was stimulated by oxygen-limited conditions near the decomposing silage. In contrast, compost incorporated by harrowing caused net N₂O uptake, presumably an effect of reduced mineral N availability in this treatment. Overall, our study revealed that ensiled grass-clover was the best fertilizer product and that the method chosen for incorporation of green manure is likely to influence N₂O emissions.     

Success of three soil restoration techniques on seedling survival and growth of three plant species in the Sahel of Burkina Faso (West Africa)

In the Sahel of Africa, where 90 % of the population depends on natural resources for their livelihood, a large part of the soils are structurally unstable,prone to crusting and hard setting, and have low water holding capacity, which hamper vegetation establishment.The effect of soil restoration techniques on survival and growth of seedlings of Acacia nilotica, Acacia tortilis and Jatropha curcas was tested in completely barren, degraded land in a Sahelian ecosystem in Burkina Faso. A total of522 seedlings(174 plants of each plant species) were planted in a randomized complete block design with three replicates combining three soil preparation techniques:half-moon, za¨? and standard plantation. Survival and growth rates evaluated over 20 months were significantly higher using the half-moon technique compared with the other two techniques. Survival rates of plant species planted using half-moon technique were 62.5, 28.57 and10.71 % for A. nilotica, A. tortilis and J. curcas respectively, but in za¨? and standard planting, seedling survival was zero. The low survival rate of J. curcas using the half-moon technique may indicate that J. curcas is unsuitable for barren and degraded land, whereas A. nilotica and A. tortilis appear to be promising tree species for rehabilitation of degraded land.     

Occurrence and associated lesions of Pasteurella multocida in porcine bronchopneumonia

With the aim to extend the present knowledge on possible systemic spreading of Pasteurella multocida in pigs with bronchopneumonia, the occurrence and associated lesions of P. multocida were described by comparing cultural detection, pathological evaluation and in situ hybridization of P. multocida in lungs, hearts and kidneys from cases of porcine bronchopneumonia. P. multocida was cultivated from the lung lesions in 114 out of a total of 148 cases of porcine bronchopneumonia. Among the 114 cases, P. multocida was also cultivated from the pericardial sacs of 40 pigs and the kidneys of seven pigs. Gross lesions and histological findings included a variety of type and stages of bronchopneumonia in connection to the isolation of P. multocida. Furthermore, chronic fibrous pericarditis, interstitial nephritis and a high proportion of lympho-histocytic nephritis were observed. In situ hybridization identified P. multocida in the majority of the lungs, none of the hearts and in half of the kidneys examined. The results show a possible low rate of systemic spreading of P. multocida from lung lesions in pigs with bronchopneumonia.     

Phenotypic variations in fruits and selection potential in Sclerocarya birrea subsp. birrea

The domestication of indigenous fruits through agroforestry is seen as one of the important issues in the transformation in the way in which land is used within rural areas. A study of the variation in fruit traits is also important as it is a prerequisite for cultivar development in the domestication process. Following an aridity gradient, phenotypic variation was assessed in fruits of Sclerocarya birrea subsp. birrea, native to West African semi-arid areas. Fruits were collected from 42 trees of various diameters in agroforestry parklands from the dry and semi-humid Sudanian zones. They were partitioned into peel, flesh and pit. Each fruit was labelled and its components were measured and weighted. The overall mean fruit mass was 18.58 ± 0.24 g (mean ± SE) but fruits from the population in the drier zone were significantly larger (19.90 ± 0.37 g vs 17.02 ± 0.24 g; P < 0.001). The results showed a strong correlation between fruits and their components (P < 0.05). Tree diameter was very weakly correlated with fruit traits. There was a high level of variation in fruit characteristics and components within and between populations. The within-population variation accounted for the greatest part (67–100%) of the total variation. Many trees, mainly from the drier zones, showed superior phenotypic traits. Five groups of trees which represented different fruit morphotypes were identified for various prospective exploitations. The results strongly support the implementation of preliminary practical conservation action and domestication of S. birrea in West Africa.     

Yield prediction in spring barley from spectral reflectance and weather data using machine learning

Accurate preharvest yield estimation is an important issue for agricultural planning purposes and precision farming. Machine learning (ML) based on readily obtained information on the cropping system, typically including spectral reflectance measurements, is an essential approach for achieving practical solutions. We tested in a 9-year soil compaction experiment the accuracy of ML-based yield predictions made up to 2 months before harvest from a Ratio Vegetation Index (RVI) and recordings of precipitation and reference evapotranspiration. The applied data set comprises 224 combinations of plots and years with measured grain yields in the range of 4.22–9.34 Mg/ha. The best ML model [i.e., with the smallest mean absolute error (MAE)] was selected automatically by the AutoML interface included in the R program package H₂O. Its cross-validated predictions made on June 30 more than 1 month before harvest showed an MAE of 0.38 Mg/ha when trained on all data from all years except the one under consideration. MAE increased to about 0.68 Mg/ha when determined 3 weeks earlier on June 10. MAE values in the range of 0.32–0.42 Mg/ha were obtained for predictions made on June 30 when based on data from at least six consecutive years; however, MAE showed no generally decreasing trend with the number of years. Yield estimations were robust towards a considerable soil variation observed within the experimental area due in part to the experimental treatments. The results show a potential of making yield predictions in barley 1–2 months before harvest, which, however, is not sufficiently early to support decisions on top-dress N fertilization.