Nephrotoxicity in lambs apparently caused by experimental feeding withNarthecium ossifragum

Seven lambs were fed a mixture of bog plants containing 15 g (wet matter)Narthecium ossifragum per kg live weight for 10 consecutive days. Their serum creatinine concentration increased from day 1 to 4 but then fell to normal by day 6 after feeding started. In the same animals, the serum magnesium concentration was increased on days 3, 4 and 5. Histopathological examination of the kidneys of 2 lambs killed after being fed 25 gN. ossifragum per kg live weight for one day revealed tubular epithelial cell degeneration and necrosis. There were no signs of disease or distress in the experimental animals and their appetite remained normal throughout the experimental period. It was concluded thatN. ossifragum is probably nephrotoxic to lambs.Abbreviations ALP alkaline phosphatase - ASAT aspartate aminotransferase - -HBA -hydroxybutyric acid - CK creatine kinase - d.m. dry matter - -GT -glutamyltransferase - GLDH glutamate dehydrogenase - MCV mean cell volume - RBC red blood cells - SEM standard error of the mean - WBC white blood cells - w.m. wet matter     

Failure to induce toxicity in lambs by administering saponins from Narthecium ossifragum

It has been suggested that saponins produced by Narthecium ossifragum (Bog asphodel) may be the direct cause of the toxicity leading to the hepatogenous photosensitivity disease alveld seen in Norwegian lambs. Lambs fed large quantities of freeze-dried N. ossifragum did not develop alveld. Chemical investigations on the freeze-dried material and fresh N. ossifragum showed no difference in their saponin content. These results indicate that alveld is not caused solely by the saponins produced by N. ossifragum.     

Tolerance to the Nephrotoxic Component of Narthecium ossifragum in Sheep: The Effects of Repeated Oral Doses of Plant Extracts

Young adult sheep were dosed with extracts of Narthecium ossifragum plants by the oral or parenteral routes and the resulting nephrotoxicity was assessed from the increases in the concentrations of creatinine and urea in the serum. Following single intraruminal or intraperitoneal doses of extracts derived from 30 g N. ossifragum (wet weight) per kg live weight (kg lw), serum creatinine concentrations increased from about 100 mol/L to between 260 and 510 mol/L. The serum urea concentrations increased from about 5–8 mmol/L to between 11 and 66 mmol/L in individual sheep. Daily intraruminal administration of 5–30 g/kg lw to three sheep over a 10- or 15-day period increased creatinine concentrations from 100 mol/L to 300–760 mol/L, and urea concentrations from 5–8 mmol/L to 35 mmol/L. A single intraperitoneal challenge dose of 30 g/kg lw, delivered 7 or 12 days after the final intraruminal dose, did not lead to increased serum creatinine or urea concentrations, indicating that oral treatment had apparently resulted in an increased tolerance to the nephrotoxic principle(s) in N. ossifragum.     

Ovine Metabolism of Saponins: Evaluation of a Method for Estimating the Ovine Uptake of Steroidal Saponins from Narthecium ossifragum

A sheep was dosed three times per day over six consecutive days with 70 g Narthecium ossifragum, and once on the seventh day with 70 g N. ossifragum. Additionally, it was dosed once on days 1–7 with 20 mg of [20,23,23-²H₃]sarsasapogenin. After 7 days, the sheep was killed and GC-MS analysis of the free and conjugated sapogenin content in bile, urine, rumen, duodenum, jejunum, colon and rectum samples collected from the sheep, faecal samples collected on days 4–7, and dosed plant material was performed. The N. ossifragum contained mainly sarsasapogenin and smilagenin. Only negligible levels of deuterium-labelled sarsasapogenins were detected in the samples from the animal. Ingested saponins were quickly hydrolysed in the rumen to free sapogenins and, in part, epimerized at C-3 to afford episapogenins. The absorption of free sapogenins appeared to occur in the jejunum. The concentration of sapogenins in faeces reached a plateau 108 h after dosing started.     

Accumulation of Sapogenin Conjugates and Histological Changes in the Liver and Kidneys of Lambs Suffering from Alveld,a Hepatogenous Photosensitization Disease of Sheep Grazing Narthecium ossifragum

Sixteen lambs exhibiting hepatogenous photosensitization (alveld) after grazing pasture containing Narthecium ossifragum and seven nonphotosensitized lambs grazing the same pastures were studied. All the alveld-affected lambs revealed liver damage dominated by single cell necrosis, portal fibroplasia and bile duct proliferation. Crystalloid clefts were demonstrated in the bile ducts of two and in the hepatocytes and Kupffer cells of nine photosensitized lambs. Plasma bilirubin concentration was severely increased in ten of the cases of alveld whereas the activity of aspartate aminotransferase was moderately to severely increased in seven cases. The activity of glutamate dehydrogenase was moderately elevated in one of the photosensitized lambs. The main histopathological findings in the kidneys from the alveld-affected lambs were dilated tubules, often with eosinophilic material in the tubular lumina. Regenerative changes were seen in a large proportion of the renal sections. Elevated plasma concentrations of urea and creatinine, and the renal histopathological changes, suggested that the photosensitized lambs had been through a phase of renal injury. Analysis of the free and conjugated sapogenin content in liver tissue and bile was performed by gas chromatography–mass spectrometry. There were significantly higher concentrations of conjugated episapogenins in both the liver and bile in the alveld-affected lambs than in the nonphotosensitized lambs.     

Fungi onNarthecium ossifragum leaves and their possible involvement in alveld disease of Norwegian lambs

Spores ofPithomyces chartarum (Berk. & Curt.) M.B. Ellis were only rarely seen on leaves ofNarthecium ossifragum (L.) Hudson collected in summer from five areas in western Norway in which alveld, a photosensitization disease of lambs, is endemic.Cladosporium magnusianum (Jaap) M.B. Ellis was found on all 118 leaf samples collected in the summers of 1990 and 1991. The hypothesis thatP. chartarum contributes to the aetiology of alveld could not be supported, but it is possible thatC. magnusianum may have a role in the causation of the disease.     

Summer Variation in the Concentration of Steroidal Sapogenins in and the Degree of Fungal Infection on Narthecium ossifragum plants from Møre og Romsdal County,Norway

Thirty-nine leaf samples ofNarthecium ossifragum collected from eight sites in More og Romsdal County, Norway, during June–September 1997 and 41 leaf samples collected at five sites in the same county during June–August 1998 were analysed for the concentrations of steroidal sapogenins using GC-MS. The 1998 samples were also examined for fungal elements (conidia and hyphae) after incubation in a moist chamber for 10–14 days. The highest 1997 and 1998 leaf sapogenin concentrations (4881 and 7115 mg/kg dry matter, respectively) were 13–14 times greater than the lowest sapogenin concentrations found (344 and 531 mg/kg dry matter, respectively). The results did not reveal systematic differences in sapogenin concentrations between the two seasons, or between samples harvested early or late in the same seasons, or between sapogenin concentrations in plants harvested at different sites.Cladosporium magnusianum was the predominant fungus found in the samples. The degree of fungal infection on the samples was in generally low, but the number ofC. magnusianum colonies in the moist chamber preparations and fungal elements (conidia and hyphae) in leaf washings and on leaves tended to increase with time. Factor analysis and multiple regression analysis performed on the chemical and fungal results suggest that sporulation may have occurred in the fungi in response to increase in sapogenin concentrations.     

Nephrotoxicity in Goats Caused by Dosing with a Water Extract from the Stems of Narthecium Ossifragum Plants

Seven goats were given a single dose of an aqueous extract derived from 30 g (wet weight) of Narthecium ossifragum per kg liveweight. Their serum creatinine and urea concentrations increased to day 5 but then fell to normal by day 10. Serum magnesium increased to day 4 and decreased to normal by day 9. Their serum calcium concentration was lower than normal on days 4, 5 and 6. Histopathological examination of the kidneys of goats killed or found dead 2, 4, 6, 8, 11 or 16 days after dosing revealed tubular epithelial cell degeneration and necrosis. Regeneration of the tubular epithelium and signs of interstitial fibroplast proliferation and fibrosis could be seen in animals killed on days 8, 11, 16 and 42. No signs of liver damage were observed in 3 goats dosed with the insoluble plant material from 40 g (wet weight) Narthecium ossifragum per kg liveweight. The total dose was divided into three doses, which were given intraruminally within 7 h. The activities of aspartate aminotransferase, -glutamyl-transferase and glutamate dehydrogenase remained within the normal range in all 10 goats after dosing.     

Further Studies on the Presence, Qualities and Effects of the Toxic Principles from Narthecium Ossifragum Plants

Flåøyen, A., Bratberg, B., Frøslie, A., Grønstøl, H., Langseth, W., Mantle, P.G. and Von Krogh, A., 1997. Further studies on the presence, qualities and effects of the toxic principles from Narthecium ossifragum plants. Veterinary Research Communications, 21 (2), 137-148One calf was dosed during one day with an aqueous extract from 3.0 kg (wet weight) of Narthecium ossifragum and another was dosed on the same day with the insoluble plant residue. The concentrations of serum creatinine and magnesium increased only in the calf dosed with the aqueous extract, while the activity of glutamate dehydrogenase increased only in the serum of the calf dosed with the plant residue, so differentiating the nephrotoxic and hepatotoxic principles as water-soluble and water-insoluble compounds, respectively.One calf was dosed with 30 g (wet weight) N. ossifragum flower stems per kg live weight during one day and another was dosed with 30 g (wet weight) N. ossifragum leaves per kg live weight on the same day. The serum creatinine and urea concentrations and also the activities of glutamate dehydrogenase, aspartate aminotransferase and -glutamyltransferase in the serum increased in the calf dosed with the flower stems, whereas there was only a slight temporary increase in the creatinine concentration in serum from the calf dosed with the leaves. However, histopathological examination of the kidneys of the calf dosed with the flower stems revealed severe tubular necrosis and degeneration. It therefore appears that both the toxic principles are present in the flower stems of N. ossifragum rather than in its leaves.The serum creatinine concentration was significantly increased in a non-ruminating calf dosed with an aqueous extract from 32 g (wet weight) N. ossifragum per kg liveweight during one day, showing the intrinsic nephrotoxicity of the plant.     

Influence of diet on the shedding of Candida glabrata by experimentally infected preweaned calves

The influence of three diets, comprising dam's milk (DM) from the same farm, commercial milk replacer with (CMRL) or without 3.2% lactose (CMR), on the duration and intensity of Candida glabrata shedding in the faeces of preweaned calves following experimental oral infection was examined. Shedding of other potential enteric pathogens was also monitored. The duration and intensity of C. glabrata shedding in DM-fed calves were reduced significantly compared with the calves fed the two diets based on milk replacers. Consequently, feeding calves with DM might disrupt the infective cycle, resulting in the yeast's elimination from a farm. In the CMR and CMRL groups, the periods of intensive shedding of C. glabrata and rotavirus overlapped but no diarrhoea was associated with the shedding of either microorganism. There was no evidence that lactose diminished colonization in vivo.     

Microsomal enzymes in lambs and adult sheep,and their possible relationship to alveld

The difference in susceptibility to alveld between lambs and adult sheep may be caused by differences in the microsomal enzyme activities in their livers. There was no difference in NADPH-cytochrome c reductase or 7-ethoxyresorufin-O-deethylase (EROD) activity between ewes, control lambs and phenobarbitone-dosed lambs 3 weeks after dosing ceased. However, aldrin epoxidase activity was at that time significantly highest in the phenobarbitone-dosed lambs and significantly lowest in the ewes. The liver cytosolic glutathione transferase activity was significantly highest in the ewes and significantly lowest in the control lambs at the same time.     

Sapogenin Levels in <Emphasis Type="Italic">Narthecium ossifragum</Emphasis> Plants and <Emphasis Type="Italic">Ovis aries</Emphasis> Lamb Faeces during Two Alveld Outbreaks in Møre og Romsdal,Norway, 2001

The proposal that saponins produced by the lily bog asphodel (Narthecium ossifragum) may be the direct cause of the hepatogenous photosensitization disease alveld seen in Norwegian lambs was investigated by comparing sapogenin levels in two control and two toxic pastures, and in faeces from lambs grazing the four pastures in the Halsa and Surnadal municipalities, Møre og Romsdal county, Norway. Generally similar levels of sapogenins, determined after hydrolysis of parent plant saponins, were found in Narthecium leaves collected in June/July 2001 from the two alveld outbreak areas and two nearby control areas. Differences in the median sapogenin levels determined for leaf samples in outbreak and control areas were not statistically significant. The total level of free and conjugated sapogenins in faeces recovered from the rectums of lambs grazing the outbreak and control pastures areas varied greatly. The results obtained do not support the hypothesis that a dose–response relationship exists between Narthecium saponin levels and the occurrence of alveld outbreaks.     

The efficacy of valnemulin (Econor) in the control of disease caused by experimental infection of calves with Mycoplasma bovis

Mycoplasma bovis infection was experimentally induced in groups of six young calves. A further group was uninfected and served as a control. Ten days after infection, medication with either enrofloxacin (Baytril, Bayer) or valnemulin (Econor, Novartis) was instituted via the milk replacer for a further 10 days, after which all calves were killed. Infection resulted in depression, pyrexia, inappetance and prominent respiratory signs. Arthritis occurred in two animals and two (unmedicated) animals died. At post-mortem examination extensive lesions were present in the lungs and M. bovis was re-isolated from infected unmedicated calves' lungs. Medication with either enrofloxacin or valnemulin resulted in a rapid diminution of clinical signs, restoration of appetite and reversal of weight loss. Isolation of Pasteurella multocida from the calves' lungs was suppressed by both medicaments. Valnemulin resulted in a more rapid reduction of clinical scores and eliminated M. bovis from the lungs more effectively than enrofloxacin.     

Bacteriological, serological, pathological and immunohistochemical studies of Mycoplasma bovis respiratory infection in veal calves and adult cattle at slaughter

Mycoplasma bovis is an important cause of calf pneumonia worldwide. In this study, we examined 140 cattle at slaughter comprising 70 veal calves and 70 beef cattle; 115 animals with pneumonic lesions and 25 without. Lung samples were submitted for bacteriological, histological, and M. bovis-immunohistochemical analyses. Serology for M. bovis was positive in 76% of beef cattle and 100% of veal calves. M. bovis was isolated only from veal calves in 16 out of 64 pneumonic cases. M. bovis was detected by immunohistochemistry in seven bacteriologically positive cases. M. bovis antigen was associated with bronchogenic necrosuppurative or fibrinonecrotizing lesions. Bacteriologically positive and immunohistochemical negative cases were associated with catarrhal bronchointerstitial pneumonia. Results suggest that M. bovis infection may develop into a severe necrosuppurative bronchopneumonia or fibrinonecrotizing pneumonia when associated with a high number of intralesional organisms or, conversely, into a mild catarrhal bronchointerstitial pneumonia when associated with a low number of organisms.     

Pathogen translocation and histopathological lesions in an experimental model of Salmonella Dublin infection in calves receiving lactic acid bacteria and lactose supplements

The purpose of this study was to evaluate the capacity of a lactic acid bacteria (LAB) inoculum to protect calves with or without lactose supplements against Salmonella Dublin infection by evaluating histopathological lesions and pathogen translocation. Fifteen calves were divided into three groups [control group (C-G), a group inoculated with LAB (LAB-G), and a group inoculated with LAB and given lactose supplements (L-LAB-G)] with five, six, and four animals, respectively. The inoculum, composed of Lactobacillus (L.) casei DSPV 318T, L. salivarius DSPV 315T, and Pediococcus acidilactici DSPV 006T, was administered with milk replacer. The LAB-G and L-LAB-G received a daily dose of 10⁹ CFU/kg body weight of each strain throughout the experiment. Lactose was provided to the L-LAB-G in doses of 100 g/day. Salmonella Dublin (2 × 10¹⁰ CFU) was orally administered to all animals on day 11 of the experiment. The microscopic lesion index values in target organs were 83%, 70%, and 64.3% (p < 0.05) for the C-G, LAB-G, and L-LAB-G, respectively. Administration of the probiotic inoculum was not fully effective against infection caused by Salmonella. Although probiotic treatment was unable to delay the arrival of pathogen to target organs, it was evident that the inoculum altered the response of animals against pathogen infection.     

Effect of bovine lactoferrin feeding on lipopolysaccharide-induced metabolic and hormonal disturbances in preruminant calves

One of the biological functions of bovine lactoferrin (LF) is modulation of the host defense system, including cytokine production and immune response. The aim of the present study was to investigate the effect of oral administration of LF in calves on lipopolysaccharide (LPS)‐induced metabolic and hormonal changes in inflammatory response. Thirty Holstein calves at 4 day of age were given one of three oral doses of LF (0, 1, 3 g/day) for 10 days (?10 day to ?1 day). They were injected i.v. with LPS (50 ng/kg bodyweight) the day (day 0) after the end of LF treatment. Plasma samples were obtained on ?10, 0 day (immediately before LPS injection), and at 2, 6, 12, 24, 48, 72, and 96 h after LPS injection. Plasma tumor necrosis factor‐α concentrations at 2 h after LPS treatment were lower (P < 0.05) in LF 1 g/day‐fed claves compared with LF 0 g/day (control) calves. On day 0 there were no significant group differences in plasma LF concentration. Plasma concentration of haptoglobin in control calves was elevated by LPS injection. In LF groups, plasma haptoglobin concentrations slightly increased after LPS injection, but those levels at 6–24 h were lower (P < 0.05) than in the control group. The LF treatment inhibited (P < 0.05) the reduction of plasma ferrin concentration in calves following LPS challenge. The concentration of plasma aspartate aminotransferase in calves treated with LF was lower (P < 0.05) than in control calves at 24–96 h after LPS treatment. The concentration of plasma insulin‐like growth factor‐1 (IGF‐1) in all groups was decreased by LPS treatment, while in the LF groups the IGF‐1 level was higher (P < 0.05) than in the control group. Plasma adrenocorticotropic hormone and insulin concentrations in LF groups were lower (P < 0.05) than in control calves at 2 h after LPS injection. These data suggest that LF has a substantial anti‐inflammatory effect on the modulation of the host defense system in preruminant calves.     

Acute phase protein changes in calves during an outbreak of respiratory disease caused by bovine respiratory syncytial virus

Bovine acute phase proteins (APPs), lipopolysaccharide binding protein (LBP), serum amyloid A (SAA), haptoglobin (Hp) and alpha₁-acid glycoprotein (AGP) were evaluated as inflammatory markers during an outbreak of bovine respiratory disease (BRD) caused by bovine respiratory syncytial virus (BRSV). Calves (n = 10) presented mild to moderate signs of respiratory disease. Secondary bacterial infections, Pasteurella multocida and Mycoplasma dispar as major species, were detected in tracheobronchial lavage samples. Concentrations of SAA and LBP increased at week 1 had the highest values at week 3 and decreased at week 4 of outbreak. Some calves had high Hp concentrations at week 3, but AGP concentrations did not rise during respiratory disease. Higher SAA, LBP and Hp concentrations at a later stage of BRD (week 3) were associated with the low BRSV-specific IgG₁ production, suggesting that these calves had enhanced inflammatory response to the secondary bacterial infection. In conclusion, APPs (especially SAA and LBP) are sensitive markers of respiratory infection, and they may be useful to explore host response to the respiratory infections in clinical research.     

Fatal meningitis in a calf caused by Mannheimia varigena

Mannheimia varigena was identified as the etiologic agent of meningitis in a young Belgian White Blue heifer calf. Species identification of the bacterium was done by phenotyping and molecularly confirmed by tDNA-PCR. Standard bacteriological examination might fail to differentiate species belonging to the genus Mannheimia.