Direct Exports of Phosphorus from Fertilizers Applied to Grazed Pastures

Since its discovery in 1669, phosphorus (P) in the form of fertilizer has become an essential input for many agroecosystems. By introducing a concentrated P source, fertilizers increase short-term P export potential soon after their application and longer-term export potential by increasing soil fertility (legacy P). The 4R concept was developed to help mitigate P exports from the fertilizers that sustain agricultural productivity. This review investigates the factors affecting P exports soon after the application of mineral fertilizers to pasture-based grazing systems and studies quantifying its potential impact in different systems, with an emphasis on Australasia. Initially, P fertilizers and reactions that might affect their short-term P export potential are reviewed, along with P transport pathways, the forms of P exported from grazing systems, factors affecting P mobilization into water, and studies demonstrating the possible short-term effects of fertilizer application on P exports. Using that foundation, we review studies quantifying the short-term impact of fertilizer application in different regions; they show that under poor management, recently applied fertilizer can contribute a considerable proportion (30-80%) of total farm P exports in drainage, but when fertilizer is well-managed, that figure is expected to be <10%. We then use three model systems of varying hydrology that are common to Australasia to demonstrate the principles for selecting fertilizers that are likely to minimize P exports soon after their application.

Evaluation and application of a paper-based device for the determination of reactive phosphate in soil solution

The evaluation and validation of a new low-cost microfluidic paper-based analytical device (μPAD) for the determination of reactive phosphate in soil solution is described. This device allows up to 15 replicate measurements of reactive phosphate on one credit card-sized device and requires only a desktop or hand scanner for signal detection and quantification. The proposed method showed a linear response between 0.1 and 1.0 mg L and between 1.0 and 10.0 mg L P with a limit of detection of 0.05 mg L P. When applied to the analysis of soil solution, there was excellent agreement between results obtained using the μPAD and those obtained by a reference spectrophotometric method, as indicated by the following regression equation: [P] = (0.997 ± 0.005)[P] - (0.020 ± 0.008) ( = 0.997; = 110). It was found that the ambient temperature storage stability of the μPAD could be extended to 15 d by incorporating a removable polymeric interleaving sheet between the adjacent paper layers of the device. The observed sensitivity of the μPADs to sunlight, which was manifested by photoreduction of the chromogenic molybdate reagent used in the assay, was overcome by preparing the μPADs with an ultraviolet-filtering laminating material. The proposed method is rapid, with a reaction time of only 10 min, is easy to perform, and is suitable for application in the field.

Risk of kidney stones with surgical intervention in living kidney donors

A kidney stone in a person with a solitary kidney requires urgent attention, which may result in surgical and/or hospital attention. We conducted a matched retrospective cohort study to determine if living kidney donors compared to healthy nondonors have a higher risk of: (i) kidney stones with surgical intervention, and (ii) hospital encounters for kidney stones. We reviewed all predonation charts for living kidney donations from 1992 to 2009 at five major transplant centers in Ontario, Canada, and linked this information to healthcare databases. We selected nondonors from the healthiest segment of the general population and matched 10 nondonors to every donor. Of the 2019 donors and 20 190 nondonors, none had evidence of kidney stones prior to cohort entry. Median follow-up time was 8.4 years (maximum 19.7 years; loss to follow-up <7%). There was no difference in the rate of kidney stones with surgical intervention in donors compared to nondonors (8.3 vs. 9.7 events/10 000 person-years; rate ratio 0.85; 95% confidence interval [CI] 0.47-1.53). Similarly there was no difference in the rate of hospital encounters for kidney stones (12.1 vs. 16.1 events/10 000 person-years; rate ratio 0.75; 95% CI 0.45-1.24). These interim results are reassuring for the safety of living kidney donation.

Markers of the uterine innate immune response of the mare

Reproductive efficiency in mares is low and persistent mating-induced endometritis (PMIE) is an important cause of subfertility. Mating-induced endometritis (MIE) an obligate precursor to PMIE, is a ubiquitous, transient inflammatory response to the presence of sperm, seminal components and pathogens. However, the specific inflammatory pathways that derive from MIE and that may also be precursors to PMIE are not clear. The ability to identify and measure robust, repeatable markers of inflammation integral to MIE may be key to understanding the progression to PMIE. The aim of the study was to (i) refine a protocol for inducing MIE and in doing so test a range of cellular and molecular parameters as valid markers of MIE to facilitate future studies of mares susceptible to PMIE (ii) concurrently identify those parameters with potential as inflammatory indicators during MIE to inform and enhance early treatment regimens in practice. Mating-induced endometritis was induced in pony mares using a stringent protocol; mares were treated intrauterine with frozen/thawed semen (n = 5; FTS) or frozen/thawed extender (n = 6: FTEx). The parameters tested were measured before treatment were compared to samples collected at strategic time points after treatment: uterine cytology using cytological (at 8, 16, 24, 48 and 72 h after treatment) or histological analysis (at 24 and 72 h); uterine bacteriology (at 24 and 72 h); secretion of prostaglandin F(2alpha) (PGF(2alpha); at 8, 16, 24, 48 and 72 h); peripheral concentrations of serum amyloid A (SAA; at 24h); endometrial mRNA gene expression, focussing upon IL8 and TLR4, as examples of genes pertinent to inflammation (at 24 h). Uterine neutrophil cell numbers in both treatment groups increased at 8 (P < 0.001), 16 (P < 0.01) and 24 (P < 0.01) h after insemination, indicative of MIE and distinguished between different treatments because neutrophil numbers were greater from FTS mares than FTEx mares 8h after challenge. Uterine neutrophil cell numbers, assessed by histology, increased (P < 0.001) 24 and 72 h after treatment. Prostaglandin F(2alpha) concentrations increased (P < 0.05) 16 h after treatments, while SAA concentrations and bacterial growth scores were not significantly different after treatment. Endometrium from pony mares expressed mRNA for IL8 and TLR4 but expression was not altered after insemination. The protocol induced MIE, as confirmed by uterine cytology and maybe used hereafter as a repeatable and robust method for studying immune mechanisms that underlie MIE and so may aid the understanding of progression to persistent inflammation. It can be concluded that of the range of parameters tested, neutrophil cell numbers by cytological analysis and PGF(2alpha) were regarded as the most accurate markers of inflammation during MIE and important for use in practice.

Endometrial explant culture to study the response of equine endometrium to insemination

Mating-induced endometritis (MIE) is ubiquitous in the horse after natural mating and artificial insemination with frozen/thawed semen causing the most aggressive response. The majority of mares eliminate MIE 24-48 h after insemination. An endometrial explant culture was tested as a potential in vitro exemplar for sperm-induced MIE. Endometrial prostaglandin F(2alpha) (PGF(2alpha)) secretion and expression of interleukin-8 (IL-8) were used as markers of inflammation. Endometrial explants were cultured from uteri collected from follicular phase mares. Explants were challenged with 1 or 10 x 10(6) sperm/ml frozen/thawed semen, chilled semen, washed sperm or seminal plasma. Medium was collected 24 and 72 h after challenge and assayed for PGF(2alpha) by radioimmunoassay. Treatment of endometrial explants with frozen/thawed, chilled semen or washed sperm did not change the secretion of PGF(2alpha) compared with untreated controls. However, 24 h after challenge cultured explants expressed IL-8. The in vitro endometrial explant system did not represent the in vivo response to semen when PGF(2alpha) was used as a marker of inflammation, yet the use of gene expression as an inflammatory marker warrants further investigation.

Sources of phosphorus lost from a grazed pasture receiving simulated rainfall

Nutrients exported from grazing systems contribute to eutrophication of surface waters. In this study the contributions of soil, pasture-plants, and dung to P exports in overland flow were compared using simulated rainfall. The treatments were (i) grazed pasture-plants (isolated from soil by application of petrolatum to the soil surface), (ii) grazed pasture-plants and supporting soil, (iii) grazed pasture-plants and soil and treading, and (iv) grazed pasture-plants and soil and treading and dung. In general, dissolved reactive P (DRP) accounted for the majority of the P exported and P losses decreased in the order: treading and dung treatment>treading>pasture-plants and soil>pasture-plants. Very little dissolved organic P was lost in overland flow and the effects of treading diminished with time. Over a normal grazing cycle (30 d), the portion of P lost from pasture-plants was approximately half that lost from pasture-plants and soil, one-third that lost from treaded pasture-plants and soil, and one-quarter that lost from treaded pasture-plants, soil, and dung. The DRP in the pasture-plants treatment was approximately half that in the pasture-plants and soil treatment and suggests that a significant portion of the P exported from these systems is derived directly from pasture-plants. Due to higher proportions of particulate P (PP) in the treaded and dung treatments, DRP accounted for less of total P than in the pasture-plants and pasture-plants and soil treatments. Lower infiltration capacities probably caused by mechanical disaggregation at the soil surface are consistent with the higher proportions of PP in the treading treatments. These results were used to estimate P exports from a field trial site in Southland, New Zealand. The results suggested that P export attributable to fertilizer, dung, pasture-plants, and soil components were approximately 10, 30, 20, and 40%, respectively. These results suggest that since 90% of the P exports are derived from the soil-plant system and dung returns, managements to lessen P exports should continue to focus on maintaining soil P within the optimal range for pasture-plant production and maintaining soil surface properties that maximize infiltration and minimize overland flow.

Steroidogenic factor-1 regulates the rate of proliferation of normal and neoplastic rat ovarian surface epithelial cells in vitro

Steroidogenic factor-1 (SF-1) is a transcription factor that is expressed by many cell types within the ovary and has been shown to inhibit granulosa cell proliferation. The present studies were designed to determine whether: 1) SF-1 is expressed by primary and transformed rat ovarian surface epithelial cells (i.e. ROSE cells); and 2) SF-1 expression effects the proliferation of both normal and neoplastic ROSE cells. These studies used immature, gonadotropin-primed and mature rat ovaries, as well as ROSE-179 cells from early passages (EP) and late passages (LP), T-sv-40 transformed ROSE cells, and T-ras transformed ROSE cells. In situ hybridization studies demonstrated that SF-1 was detected in the surface epithelium of rat ovaries, independent of age or gonadotropin treatment. Further, Northern blot and quantitative in situ hybridization studies revealed that significant amounts of SF-1 messenger RNA (mRNA) were present in EP-ROSE-179 cells but not in the other cell lines. Interestingly, EP-ROSE-179 cells proliferated at a significantly slower rate than the other cell lines. Further, SF-1 mRNA levels were higher in EP-ROSE-179 cells in the G0/G1 stage than in the S-, G2/M stage of the cell cycle. These observations suggest that a cause and effect relationship exists between the level of SF-1 expression and cell proliferation. To test this hypothesis, LP, T-sv-40, and T-ras ROSE cells were transfected with either control vector or SF-1 expression vector. Forty-eight hours after transfection, SF-1 expression was assessed by in situ hybridization, and the fold increase in cell number/24 h was determined. For each cell line, about 30% of the cells were successfully transfected. The fold increase in the number of cells observed after transfection with the SF-1 expression vector was significantly less than the increase in cell number after transfection with the control vector (P < 0.05). To confirm that the forced expression of SF-1 prevented proliferation, LP cells were cotransfected with a green fluorescent protein (GFP) expression vector and either control vector or SF-1 expression vector. This study demonstrated that virtually none of the GFP/SF-1-transfected cells proliferated over a 24-h period, whereas GFP/Control vector-transfected cells proliferated. Further, approximately 40% of the GFP/SF-1-transfected cells underwent apoptosis after 24 h of culture in serum-supplemented medium. These data demonstrate that: 1) normal ovarian surface epithelial cells express SF-1; 2) SF-1 is also expressed by EP-ROSE-179 cells, but its expression seems to be suppressed when the cells enter the cell cycle; 3) LP-, T-sv, and T-ras ROSE cells do not express SF-1 mRNA; and 4) the inability to express SF-1 is associated with an increase in cell proliferation. Finally, forced SF-1 expression interferes with serum-induced proliferation and leads to apoptosis.

The effect of dietary menhaden meal and storage on the omega-3 fatty acids and sensory attributes of egg yolk in laying hens

The effect of dietary menhaden meal (MM) on production and egg yolk lipids of commercial White Leghorn hens was studied for 350 d. One hundred and ninety-two birds were given a corn-wheat-soybean diet that contained either 0, 4, 8, or 12% MM. Analysis of the egg yolks at four periods in the laying cycle (162, 211, 254, and 289 d) was performed on the fresh and stored (4 wk at 4 °C, [Formula: see text]) egg yolks. Sensory evaluation was performed on fresh eggs collected at the end of the laying cycle (448 d).Production whether measured as hen-day or hen-housed, increased linearly with the inclusion of MM in the diets. The level of eicosapentaenoic and docosahexaenoic acids increased 10- and 2.6-fold to give levels of 9 and 95 mg yolk−1, respectively. Storage had no effect (P > 0.05) on these parameters. Sensory data suggested that the level of MM in the diets of laying hens should be between 4 and 8% in order to avoid off-flavours in eggs. Key words: Menhaden meal, laying hens, omega-3 fatty acids, storage, eicosapentaenoic acid, docosahexaenoic acid

Volume imaging: three-dimensional appreciation of the fetal head and face

Quasi-three-dimensional volume imaging provides an inexpensive means of evaluating the usefulness of three-dimensional imaging. The technique works most efficiently with water-skin interfaces and therefore we investigated its application in obstetrical ultrasonography. Three-dimensional perspectives of the normal and abnormal fetal head and face were spectacular and at times provided more information than the two-dimensional images. The ability of an inexperienced observer to interpret the three-dimensional image more easily may have a role in training sonographers and counseling parents whose fetuses have structural defects. Volume imaging has certain limitations and can only be used as a complementary technique.

The effect of dietary herring meal on the omega-3 fatty acid content of plasma and egg yolk lipids of laying hens

The effect of dietary HM on plasma and egg yolk lipids of commercial White Leghorn hens was studied over 350 d. A total of 192 birds were given corn-wheat-soybean meal diets that contained either 0, 4, 8, or 12% HM. Analysis of plasma lipids at four periods in the laying cycle (169, 211, 253 and 287 d) and at five times during the test day (0800, 1000, 1200, 1400 and 1600 h) were performed. Egg lipids were analyzed at each of the four periods.Plasma total lipids were inversely related (P < 0.01) to dietary HM levels while omega-3 and omega-6 fatty acid levels were positively and inversely related (P < 0.001), respectively. HM levels did not influence the total lipid content of the egg yolk lipids but omega-3 and omega-6 fatty acid content were positively and inversely related, respectively. The levels of eicosapentaenoic (20:5n3, EPA) and docosahexaenoic (22:6n3, DHA) acid were 11 and 3 times higher, respectively (7.8 and 100.5 mg yolk−1) in the yolks from hens given the 12% HM diet compared to the control diet. Key words: Herring meal, laying hens, omega-3 fatty acids, eicosapentaenoic acid, docosahexaenoic acid

A pneumatic device for attaching wing bands to day-old chicks

A device for attaching aluminum bands to the wings of day-old chicks is described and illustrated. It is powered with compressed air and utilizes both hand and foot operated controls. Using this device, an operator can apply wing bands without an assistant at rates up to 300 chicks/hour.

Pathological changes associated with the feeding of soybean oil or oil extracted from different rapeseed cultivars to single comb white Leghorn cockerels

A total of 384 Single Comb White Leghorn cockerels of the Hyline strain were fed either a basal (control) diet containing no added oil or a diet supplemented with 20% by weight of soybean oil, rapeseed oil from cultivars Tower, Candle, a mixture of Echo and Arlo high erucic acid rapeseed (HEAR), or R-500. Levels of erucic acid (22:1) in the rapeseed diets varied from .03 to 10.31%. Three birds from each unit were killed at 28, 56, 84, and 112 days and a wide range of tissues were examined histologically. A number of birds in all dietary groups had healed lesions of avian encephalomalacia. Two cockerels fed HEAR oil and 12 fed R-500 developed marked ascites, firm shrunken livers, hydropericardium, and cachectic muscular atrophy. Marked periacinar necrosis was present in birds dying with ascites. A significantly higher number of birds fed the rapeseed oils developed hepatic sinusoidal distention than birds fed the basal or soybean oil diets. Degenerative myocardial changes were seen only in R-500 and HEAR oil-fed birds. This, coupled with hepatic changes, producing shrunken firm livers, led to development of ascites, cachectic muscular atrophy, and periacinar hepatic necrosis. These changes were probably produced by the high erucic acid content of the HEAR and R-500 oils and the resultant grossly imbalanced diet.

Some aspects of the composition of avian ascitic fluid

Ascitic fluid from male Single Comb White Leghorn chickens fed a diet containing 20% by weight rapeseed oil rich (51.6 weight percent) in erucic (22:1n9) acid contained 2.84 +/- .09 g/dl protein and 2.55 +/- .22 micrograms/ml DNA. A characteristic feature of ascitic fluid as compared to liver and plasma was its high polyunsaturates, low saturates, and low saturate to unsaturate ratio. In general, the fatty acid profile of ascitic fluid is more comparable to the fatty acid profile of plasma lipids than to that of liver lipids. These data suggest that there is no direct absorption of fat and transfer to the ascitic fluid.

Growth, heart weight, cardiac lipid, and pathology of chickens fed soybean oil or oil extracted from different rapeseed cultivars

A total of 384 male Single Comb White Leghorn chicks of the Hyline strain were randomized in 24 Petersime battery units of 16 birds per unit. Four replicate pens were fed either a basal (control) diet containing no added oil or a diet supplemented with 20% by weight of either soybean oil or rapeseed oil (RSO) from cultivars Tower, Candle, Regular, or R-500. Levels of crucic acid (22:1) in the RSO's ranged from .1 to 51.6%. Four birds from each unit were killed at 4, 8, 12, and 16 weeks for cardiac lipid analysis and pathology. Feeding RSO had no consistent effect on body weights, heart weights, or the heart-to-body weight ratio. Only the diet containing R-500 (51.6% 22:1) consistently increased cardiac lipid levels as measured gravimetrically. Maximum deposition of the long-chain monoenes (22:1) and eicosenoic acids (20:1) occurred in the cardiac lipids by 8 weeks, and the levels remained high throughout the 16-week trial. The relative concentration of these long-chain monoenes in the cardiac lipids was positively correlated to the dietary levels of these acids. The incidence of lesions found in heart, liver, and skeletal muscle was significantly higher in chickens fed RSO's high in 22:1 than in chickens fed control or soybean oil, and the incidence significantly correlated to the level of 22:1 in the diet. The incidence of heart and muscle lesions and sinusoidal distention in chickens fed RSO's low in 22:1 was not significantly different from that of chickens fed the control diet or soybean oil, but the incidence of hepatic necrosis was significantly higher for chickens fed RSO's low in 22:1 compared to those fed the control diet or soybean oil.

Polychlorinated biphenyls: metabolic behavior of pure isomers in pigeons, rats, and brook trout

The metabolic behavior of pure mono-, di-, tetra-, and hexachlorobiphenyl isomers in pigeons, rats, and brook trout was investigated. Excreta from these animals were extracted and examined by chromatographic and mass spectrometric techniques. The results showed conversion of the 4-chloro-, 4,4'-dichloro-, and 2,2',5,5'-tetrachlorobiphenyl isomers into monohydroxylated derivatives by the rat and pigeon whereas no hydroxymetabolites were detected in the excreta of the brook trout. No hydroxylated products of 2,2',4,4',5,5'-hexachlorobiphenyl were detected in the excreta of pigeons, rats, or brook trout.