Restricted energy intake and elevated calcium and phosphorus intake for boars during growth. II. Foot and leg measurements and toe and soundness scores

Boars were assigned at 5 wk of age in a 2 X 2 factorial arrangement to two energy (ad libitum and 75% of ad libitum) and two Ca and P levels (100 and 150% of the National Research Council daily recommended amounts) to determine the effect of reduced growth rate and elevated Ca and P intake on foot and leg measurements, pad and horn incidence and severity of lesions, and structural soundness. There were 20 boars/treatment; 15 boars from each treatment were necropsied at 10 +/- 2-d intervals from 80 to 220 d of age (45 to 185 d on test), with the remaining five boars in each treatment being necropsied at 220 d of age. Feet and leg measurements were taken and toe pads and horns were scored initially and after 78 and 131 d on when necropsied. Boars remaining after 130 d on test were scored for overall structural soundness. Toe size and circumference and length of limbs increased as boars grew, with larger values for ad libitum-fed compared with limit-fed boars when observed at a constant age. However, when these values were corrected for body weight, the effect of energy was generally removed and, in some cases, reversed. Limit-fed boars appeared to have fewer pad and horn lesions, but the effects were inconsistent. In general, Ca and P levels had little or no effect on toe and limb sizes and pad and horn lesion scores, whether or not the values were expressed on a constant age or corrected body weight basis. A comparison of inside and outside toes on the front and hind feet revealed that outside toes were larger than inside toes, with the magnitude of the difference much larger for the hind foot than for the front foot. The hind inside toes had fewer pad and horn lesions. Structural soundness scores were more desirable in ad libitum-fed compared with limit-fed boars; but, elevated Ca and P levels had no effect. Thus, these data do not support a hypothesis that structural soundness can be improved by reducing the growth rate of developing boars or by feeding an elevated level of Ca and P.     

A radiographic characterization of toe length disparity and its relation to nutrition and structural unsoundness in boars, barrows and sows

The front and hind feet from a total of 64 boars, 86 sows and 107 barrows were radiographed after necropsy to study the nature of inequalities in digits and their relation to nutrition and structural unsoundness in swine. Boars were fed ad libitum or 75% ad libitum with 100 or 150% of 1979 NRC recommended vitamin-mineral levels, whereas, sows were fed the same two levels of energy with 100 or 150% of NRC recommended calcium-phosphorus (Ca-P) levels during the growing-finishing period. Barrows were fed two sources of phosphorus with increasing levels of sodium. Radiographs of metacarpals, metatarsals and associated phalanges were measured for length and deviations of proximal and distal extremities. The length of both medial and lateral bones were longer (P less than .05) in boars fed 75% ad libitum than in the ad libitum-fed group, which was probably due to age (285 +/- 8.7 vs 240 +/- 8.4 d). Dietary energy and Ca-P level did not influence the bone lengths in sows. Similarly, dietary phosphorus source or sodium level had no influence on bone lengths or deviations in barrows. The incidence of inequality in digits with a smaller medial digit was 90.9% in boars, 96.7% in sows and 87.6% in barrows. In boars and sows, the inequality in digits of front feet was due to lower positioning of proximal extremities of lateral bones because the total lengths of both medial and lateral bones were approximately equal. In hind feet, this inequality was more due to longer lateral bones because the proximal extremities of metatarsals were positioned at approximately an equal level.(ABSTRACT TRUNCATED AT 250 WORDS)     

Cu‐, Zn‐ und Cd‐Aneignungsvermögen von zwei Spinatgenotypen in Abhängigkeit von der P‐Versorgung und Wurzelexsudation

Cu, Zn, and Cd acquisition by two spinach cultivars depending on P nutrition and root exudation Within a spectrum of 11 spinach cultivars (cvs) differences in the Cu, Zn, and Cd contents of shoots had been noticed. The aim of this study was therefore to analyze in more detail the acquisition of Cu, Zn, and Cd by the most differing cultivars (Tabu and Monnopa) in dependence on P nutrition. The plants were grown in a low phosphorus Luvisol (pH 6.3; total contents Cu: 89, Zn: 297, Cd: 2.4 mg kg^—1) with two phosphorus levels in pots under natural conditions. For the determination of inflow, root length/shoot weight ratio and of the Cu, Zn, and Cd concentration in the soil solution (rhizosphere) plants were harvested 26 and 40 days after sowing. Root exudation of organic acids of the two cvs was measured 35 days after growing in quartz sand with different P supply. Both cultivars responded to P fertilizer by doubling their shoot weight. With increased P supply (0.68—0.77% P in shoot‐DM) both cultivars showed similar heavy metal contents in the shoot resulting from similar root length/shoot weight ratios (RSR) and net uptake rates of the three elements as well as the same element concentrations in the rhizosphere soil solution. Under P deficiency, however, cv. Tabu (0.52% P in shoot‐DM) showed in comparison with cv. Monnopa (0.48% P) higher Cu, Zn, and Cd contents of shoots although its RSR was smaller than that of cv. Monnopa. However, the inflow for Cu was higher and for Zn and Cd significantly higher compared with cv. Monnopa. This result of cv. Tabu corresponded with higher concentrations of Cu, Zn, and Cd of its rhizosphere soil solution, and its higher exudation rates of oxalate, citrate, and malate (3.9; 1.0; 0.7 nmol cm^—1 h^—1). The corresponding values for cv. Monnopa were: 1.7; 0.3; 0.4 nmol cm^—1 h^—1. The mobilization of Cu, Zn, and Cd by the excreted organic acids seems to be responsible for the higher Cu, Zn, and Cd inflow of cv. Tabu.     

Characteristic volatiles from young and aged fruiting bodies of wild Polyporus sulfureus (Bull.:Fr.) Fr

The volatile compounds of fresh fruiting bodies of wild Polyporus sulfureus (Bull.:Fr.) Fr. growing on oak trees were isolated by continuous liquid-liquid extraction (CLLE) and investigated by high-resolution gas chromatography-mass spectrometry (HRGC-MS) on two GC columns of different polarity (DB-5 and ZB-WAX), and by gas chromatography-olfactometry (GC-O). A total of 40 major volatile compounds from the young samples were identified and semiquantified. Five odorous compounds were determined to be responsible for the characteristic flavor of young Polyporus sulfureus: 1-octen-3-one, 1-octen-3-ol, 3-methylbutanoic acid, phenylethanol, and phenylacetic acid. Four volatiles investigated by GC-O and detected by GC-MS were determined as the characteristic odorants of aged species: 2-methylpropanoic acid, butanoic acid, 3-methylbutanoic acid, and phenylacetic acid. The comparative results revealed that the volatile composition of the fruiting bodies even from the same fungal species may greatly vary with its host, location, and age.     

Studies on water transport through the sweet cherry fruit surface. 10. Evidence for polar pathways across the exocarp

Water uptake through the fruit surface is considered as an important factor in cracking of sweet cherry (Prunus avium L.) fruit. Uptake may occur by diffusion and/or viscous flow along a polar pathway. To establish the mechanism of water uptake, the effects of viscosity and molecular weight of selected osmotica on water uptake into detached sweet cherry fruit were investigated. In addition we investigated the effect of temperature on penetration of 2-(1-naphthyl)[1-(14)C]acetic acid ([(14)C]NAA; pK(a) = 4.2) as a molecular probe in the non-dissociated (pH 2.2) and dissociated (pH 6.2) forms. Rates of water uptake were linearly related to the inverse viscosity of gum arabic solutions (range of concentrations and dynamic viscosities 10-300 g L(-1) and 1.3 x 10(-3) to 115.9 x 10(-3) Pa s, respectively). When fruit was incubated in solutions of osmotica of differing molecular weight that were isotonic to the fruit's water potential, water uptake depended on the molecular weight of the osmoticum [range 58-6000 for NaCl to poly(ethylene glycol) 6000 (PEG 6000)]. There was no uptake from PEG 6000 solutions, but rates of water uptake increased as the molecular weight of the osmotica decreased. Apparent water potentials of sweet cherry fruit, determined by incubating fruit in concentration series of selected osmotica, increased as the molecular weight of the osmotica increased up to 1500 and remained constant between 1500 and 6000. Reflection coefficients (sigma) estimated from this relationship were closely related to hydrodynamic radii (r) of the osmotica [sigma = 1.0(+/-0.0) - [10.9(+/-0.9) x 10(-11)][r(-1) (m(-1))], R(2) = 0.97, P < 0.0001]. The permeability of the sweet cherry fruit exocarp to NAA (pK(a) = 4.2) and temperature dependence of NAA permeability (P(d)) as indexed by the energy of activation (E(a), temperature range 5-35 degrees C) were significantly higher for the non-dissociated NAA (pH 2.2, P(d) = 10.2(+/-0.8) x 10(-8) m s(-1), E(a) = 67.0 +/- 1.7 kJ mol(-)(1)) than for the dissociated NAA (pH 6.2, P(d) = 1.1(+/-0.2) x 10(-8) m s(-1), E(a) = 51.8 +/- 1.9 kJ mol(-)(1)). The activation energy for penetration of the dissociated NAA was closely related to the stomatal density (R( 2) = 0.84, P < 0.0001) but less so for the non-dissociated NAA (R(2) = 0.30, P < 0.03). These data provide evidence for the presence of polar pathways through the sweet cherry fruit exocarp that allow water uptake by viscous flow. These pathways offer a potentially useful target for strategies to reduce water uptake and fruit cracking, provided that a technique is identified that selectively "plugs" these pathways.     

Relationship between water and nitrogen uptake in nitrate‐ and ammonium‐supplied Phaseolus vulgaris L. plants

Sole ammonium supply provokes negative effects on dry‐mass formation, leaf growth, and water uptake of ammonium‐sensitive plants. To study the effects of N form on nutrient and water uptake and aquaporin expression, French bean plants were grown in a split‐root system. Five treatments were compared: homogeneous nitrate (NN) and ammonium (AA) supply; spatially separated supply of nitrate and ammonium (NA); and half of the root system supplied with N‐free nutrient solution, the other half with either nitrate (N0) or ammonium (A0). Ten days after onset of treatments, root dry mass (DM) and water‐uptake rate (WUR) were significantly reduced under ammonium compared to nitrate supply. WUR from nitrate‐supplied vessels was 80% higher than that from N‐free nutrient solution, while WUR from N‐free nutrient solution was 130% higher than that from ammonium‐supplied vessels. Potassium uptake was lower under ammonium supply and the ratio of N : K uptake of treatment AA was significantly higher compared to others. High K uptake from N‐free nutrient solution of A0 plants resulted in a ratio of N : K uptake comparable to nitrate‐supplied plants, but shoot growth resembled that to plants under sole ammonium supply. Within 24 h after onset of treatments, expression of aquaporin was lower under ammonium compared to nitrate supply. From these data, it can be concluded that reduced root water transport under ammonium supply is directly related to aquaporin activity.     

Wheat yield prediction by zero sink and equilibrium-type soil phosphorus tests

Diffusive gradients in thin films (DGT) measurements have been shown to outperform other phosphorus (P) tests in soils with strong P sorption, but this has not been confirmed for moderately weathered European soils. We compared the performance of DGT in predicting wheat grain yield in Swedish long-term fertility experiments with those of standard intensity (water-extractable P (P-H₂O)) and quantity (ammonium lactate-extractable P (P-AL)) tests. A Mitscherlich-type model was used to fit wheat yield response to P application rates (0, 15, 30 or 35, and 45 kg P ha^-1 year^-1) in each individual trial replicate to estimate the maximum yield. For trials with clear plateau-type yield responses and the goodness of fit (R²) > 0.75, relative yields (RYs) were calculated for each P treatment and plotted against the soil P test results (n=143). The goodness of the Mitscherlich-type fits decreased in the following order:DGT-measured P (P-DGT) (R²=0.35) > P-H₂O (R²=0.18) > P-AL (R²=0.13). When excluding soils with P-AL:P-DGT ≥ 0.1 L g^-1, R² was considerably improved to 0.55 for P-AL, 0.46 for P-H₂O, and 0.65 for P-DGT (n=61). At 95% of maximum yield, the upper limit of P deficiency for P-DGT was 44.8 (the soils with P-AL:P-DGT < 0.1 L g^-1) and 61.9 μg L^-1 (all soils), falling within the range reported for other European and Australian soils (6.0-142 μg L^-1). We show that in the investigated Swedish soils, DGT performed better than the quantity and intensity tests, which is attributed to its ability to capture P diffusion and resupply from the soil solid phase, similar to plant roots in the rhizosphere.     

Latitude and Date of Sowing Influences Phenology of Photoperiod‐Sensitive Sorghums

Matching phenology with prevalent abiotic and biotic conditions is a prerequisite for varietal adaptation to the environment. That is particularly important in the context of climate change because an increase in temperature is most likely to modify the precocity of the varieties. The forecast of flowering time in photoperiod‐sensitive sorghum is complex as flowering depends on temperature, day length and soil fertility. The objectives of this work were to quantify effects of latitude on the development of selected sorghum varieties and to verify the precision of our models to predict sorghum maturity. A field experiment at three locations along the latitudinal gradient in Mali with staggered sowing dates (SDs) was conducted. Seven sorghum cultivars covering a wide range of the diversity of cultivated sorghums in Mali were sown on the 10 of June, July and August in 2009 and 2010. Duration of the vegetative phase strongly decreased with latitude. Although the maximum day length difference between locations was < 8 min, for some varieties, we observed a reduction in crop duration of up to 3 weeks. Some varieties were photoperiod insensitive at one location but became photoperiod sensitive at another. The effect of latitude on the phenology is underestimated by the existing models. To determine the optimal areas for the varieties in West Africa and to forecast the effects of climate change, a correction of the simulation coefficients taking account of latitude is proposed. But, in the end, it will be necessary to develop a new model that will be able to predict the effects of both SD and latitude. More research is needed to understand physiological response mechanisms of the pronounced latitude effects on sorghum phenology.     

Development and initial validation of a sensory threshold examination protocol (STEP) for phenotyping canine pain syndromes

Objective

To study the feasibility and test–retest repeatability of a sensory threshold examination protocol (STEP) and report the quantitative sensory threshold distributions in healthy dogs.

The influence of the herbicide 2-methyl-4-chlorophenoxyacetic acid (MCPA) on the mineralization of litter-derived alkanes and the abundance of the alkane monooxygenase gene (alkB) in the detritusphere of Pisum sativum (L.)

In the present study, the temporal and spatial variation of the abundance of the alkane monooxygenase gene alkB and 16S rRNA genes in different soil compartments was analysed in the presence or absence of 2-methyl-4-chlorophenoxyacetic acid (MCPA) after the addition of pea litter to soil in a microcosm study. Samples were analysed shortly after litter addition (T0) and 1?week (T1), 3?weeks (T3) and 6?weeks (T6) after the addition of litter. In addition also, the quantity and quality of litter-derived alkanes was analysed and measured. The results revealed a fast and complete degradation of MCPA in all compartments throughout the experiment. Nevertheless, significant changes in the distribution patterns of short- and middle-chained alkanes suggest an interaction of MCPA and alkane degradation. alkB gene copy numbers were highly influenced by the time point of analysis and by the investigated soil compartment. Overall, an increase in alkB gene copy numbers from T0 to T3 was visible in the upper soil compartments whereas a decrease compared to T0 was measured in the deeper soil compartments. MCPA addition resulted in an increase of alkB abundance at T6. Gene copy numbers of 16S rRNA were not influenced by sampling time and soil compartment. In contrast to the control treatments, a slight increase in 16S rRNA gene copy numbers was visible at T1 and T3 compared to T0 in all soil compartments.