Effect of Pasteurella haemolytica infection on the distribution of sulfadiazine and trimethoprim into tissue chambers implanted subcutaneously in cattle

A study was designed to determine the effect of Pasteurella haemolytica infection on the rate and extent of penetration of sulfadiazine and trimethoprim into tissue chambers implanted SC in cattle. Thermoplastic tissue chambers were implanted SC in 6 calves. At 35 days after implantation, sulfadiazine (25 mg/kg of body weight) and trimethoprim (5 mg/kg) were administered IV to 5 of the calves. Chamber fluid and blood samples were collected from each animal at various time intervals for 24 hours after administration. Ten days later, all chambers were inoculated with P haemolytica serotype 1. At 36 hours after inoculation, a second pharmacokinetic study was conducted, using sulfadiazine and trimethoprim. Drug doses and sampling schedules were identical to those used prior to inoculation. A histologic study of infected chamber tissue was conducted, using the calf not included in the pharmacokinetic studies. Disposition curves of antimicrobials in serum and chamber fluid were well described by 2-compartment and 1-compartment pharmacokinetic models, respectively. Inoculation of P haemolytica into tissue chambers was accompanied by marked changes in the composition of chamber fluid. Increased total protein and albumin concentrations, decreased pH, and disruption of chamber tissue vasculature were associated with a significant increase in the penetration of sulfadiazine and trimethoprim into infected tissue chambers, compared with that in noninfected chambers. This increased penetration was accompanied by increases in the apparent volume of distribution for sulfadiazine and trimethoprim.     

Penetration of ceftiofur into sterile vs. Mannheimia haemolytica-infected tissue chambers in beef calves after subcutaneous administration of ceftiofur crystalline free acid sterile suspension in the ear pinna

The effect of Mannheimia haemolytica infection on the penetration of ceftiofur and desfuroylceftiofur metabolites into tissue chambers was studied in cattle after subcutaneous administration of ceftiofur crystalline free acid sterile suspension (CCFA-SS). Four tissue chambers were implanted subcutaneously in each of 12 calves. Approximately 45 days after implantation, two chambers were inoculated with M. haemolytica (10(6) colony-forming units per chamber) while the remaining two chambers were inoculated with sterile phosphate-buffered saline. Twenty-four hours after inoculation, CCFA-SS was administered subcutaneously in the middle third of the caudal ear pinna of each calf. Chamber fluid and blood samples were collected at predetermined times for 10 days following dosing and analyzed for ceftiofur and desfuroylceftiofur metabolites by high-performance liquid chromatography. Concentrations of ceftiofur and desfuroylceftiofur metabolites in plasma and tissue chamber fluid remained above a threshold of 0.2 microg/mL for at least 8 days. Infected tissue chamber fluid concentrations of ceftiofur and desfuroylceftiofur metabolites were significantly higher than those in non-infected tissue chamber fluid, which correlated with significantly higher total protein concentration in infected tissue chambers. These results indicate that single subcutaneous administration of CCFA-SS at 6.6 mg/kg can be expected to provide effective therapy of susceptible bacterial infections for a period of at least 1 week.     

Penetration of parenterally administered ceftiofur into sterile vs. Pasteurella haemolytica-infected tissue chambers in cattle

The effect of bacterial infection on antibiotic activity and penetration of parenterally administered ceftiofur into implanted tissue chambers was studied in cattle. Tissue chambers were implanted subcutaneously in the paralumbar fossae of eight calves (256-290 kg body weight). Approximately 80 days after implantation, the two chambers on one side of each animal were inoculated with Pasteurella haemolytica (10⁶ CFU/chamber). Eighteen hours after inoculation, ceftiofur sodium was administered intravenously (5 mg/kg) to each of the calves. Non-infected chamber fluid, infected chamber fluid and heparinized blood samples were collected immediately before and at 1, 3, 6, 12 and 24 h after drug administration. Concentrations of ceftiofur and desfuroylceftiofur metabolites and ceftiofur-equivalent microbiological activity were measured by high-pressure liquid chromatography and microbiological assay respectively. Concentrations of ceftiofur and desfuroylceftiofur metabolites and antimicrobial activity in P. haemolytica -infected tissue chambers were significantly higher than those in non-infected tissue chambers at all sampling times, indicating that ceftiofur, regardless of the method used for analysis, localizes at higher concentrations at tissue sites infected with P. haemolytica . Antibiotic activity-concentration ratios were lower in plasma and infected chamber fluid compared with non-infected chamber fluid, suggesting that antibiotic was bound to proteins. However, higher antimicrobial activity in the infected chamber fluid compared with the non-infected chamber fluid suggests that active drug is reversibly bound to proteins. Protein-bound desfuroylceftiofur may represent a reservoir for release of active drug at the site of infection in the animal.     

Interaction between Pasteurella haemolytica, sulfadiazine/trimethoprim, and bovine viral diarrhea virus

A study was designed to develop and define a sc tissue chamber as a suitable device for establishing a soft-tissue infection model in cattle and to use this model to study the interaction between Pasteurella haemolytica, sulfadiazine/trimethoprim, and bovine viral diarrhea virus (BVDV). Thermoplastic tissue chambers were implanted in the paralumbar fossae of 20 calves. At 35 days after implantation, calves were allotted to 4 groups of equal size and the calves in 2 groups were inoculated intratracheally with a New York-1 strain of BVDV. At 45 days after implantation, all chambers were inoculated with a 6-hour culture of P haemolytica serotype 1. Starting 36 hours after bacterial inoculation, sulfadiazine/trimethoprim was administered IV once a day to half of the virus-inoculated calves and to half of those calves that had not been exposed to virus. Inoculation of P haemolytica into tissue chambers resulted in the establishment of a localized soft-tissue infection, characteristic of pneumonic pasteurellosis. Despite the maintenance of chamber antimicrobial concentrations that exceeded minimal bactericidal concentrations established in vitro, the infections were not sterilized. This lack of efficacy was associated with decreased pH and increased protein concentrations in chamber fluids after inoculation. Infection with BVDV, which is thought to depress host defenses, had no effect on the response of P haemolytica to sulfadiazine/trimethoprim administration. Observation of responsive antibody titers, bacterial phagocytosis, and high leukocyte viability within P haemolytica-infected chambers documented functional host defenses within tissue chambers.     

Distribution of ceftiofur into Mannheimia haemolytica‐infected tissue chambers and lung after subcutaneous administration of ceftiofur crystalline free acid sterile suspension

Washburn, K., Johnson, R., Clarke, C, Anderson, K. Distribution of ceftiofur into Mannheimia haemolytica‐infected tissue chambers and lung after subcutaneous administration of ceftiofur crystalline free acid sterile suspension. J. vet. Pharmacol. Therap. 33 , 141–146. The objective of this study was to evaluate the penetration of ceftiofur‐ and desfuroylceftiofur‐related metabolites (DCA) into sterile and infected tissue chambers, lung tissue and disposition of DCA in plasma across four different sacrifice days postdosing. Twelve healthy calves were utilized following implantation with tissue chambers in the paralumbar fossa. Tissue chambers in each calf were randomly inoculated with either Mannheimia haemolytica or sterile PBS. All calves were dosed with ceftiofur crystalline free acid sterile suspension (CCFA‐SS) subcutaneously in the ear pinna. Calves were randomly assigned to 4 groups of 3 to be sacrificed on days 3, 5, 7 and 9 postdosing. Prior to euthanasia, plasma and tissue chamber fluid were collected, and immediately following euthanasia, lung tissue samples were obtained from four different anatomical sites DCA concentration analysis. Results of our study found that, in general, DCA concentrations followed a rank order of plasma > infected tissue chamber fluid > noninfected tissue chamber fluid > lung tissue. Data also indicated DCA concentrations remained above the therapeutic threshold of 0.2 μg/mL for plasma and chamber fluid and 0.2 μg/g for lung tissue for at least 7 days post‐treatment.     

Systemic and tissue chamber fluid platinum concentrations released from cis-diamminedichloroplatinum II-impregnated polymethylmethacrylate in healthy dogs

OBJECTIVES: To determine systemic and local platinum concentrations released from subcutaneously implanted cis-diamminedichloroplatinum (cisplatin) -impregnated polymethylmethacrylate (PMMA) and to evaluate systemic or local adverse reactions. ANIMALS: 6 healthy dogs. PROCEDURE: Cisplatin (20 mg) was inserted into PMMA that was fashioned into cylinders and placed into subcutaneous tissue chambers overlying the thorax (treated site). An empty tissue chamber was placed over the opposite side (control site). Plasma samples were obtained for platinum determination before implantation, at 3, 6, and 12 hours after implantation on day 0, and once daily on days 1, 2, 3, 7, 14, 21, and 29. At similar times on similar days, tissue chamber fluid samples also were obtained for platinum determination. Complete blood count, serum urea nitrogen and creatinine concentration determinations, and urinalyses were performed on days 1, 2, 3, 7, 14, 21, and 29. Complete necropsy was performed at conclusion of the study. RESULTS: Tissue chamber platinum concentrations at the treated site were significantly greater than plasma and control site tissue chamber concentrations on days 2, 3, 7, 10. Mean plasma platinum concentration at 3 (0.735 microg/ml), 6 (0.691 microg/ml), 12 (0.534 microg/ml), 24 (0.131 microg/ml), 48 (0.2 microg/ml), 72 (0.1 microg/ml), and 158 (0.014 microg/ml) hours was significantly greater than pretreatment values (0.0 microg/ml). Plasma platinum concentration 10 days after treatment (0.011 microg/ml) did not significantly differ from pretreatment values. Local or systemic adverse reactions were not apparent. CONCLUSIONS: The route of cisplatin administration was safe. Greater concentration of platinum was released locally relative to plasma concentration for an extended period.     

Distribution of intramuscularly administered erythromycin into subcutaneous tissue chambers before and after inoculation with Pasteurella haemolytica

Distribution of erythromycin into subcutaneous tissue chambers was characterised pharmacokinetically and the effect of Pasteurella haemolytica infection on the extent of penetration was studied. Thermoplastic tissue chambers were implanted subcutaneously in the paralumbar fossae of six calves. Thirty-five days after implantation, the tissue chamber distribution of intramuscularly administered erythromycin (30 mg kg⁻¹) was studied. Chambers were then inoculated with P haemolytica and the tissue chamber pharmacokinetics of erythromycin were again studied. Diffusion of erythromycin into tissue chambers was best described using a two-compartment model with tissue chambers representing a relatively inaccessible compartment. Despite changes in chamber fluid pH, the extent of erythromycin penetration into chambers was not affected by P haemolytica inoculation. Comparison of computer simulated concentration-time curves resulting from different routes of administration revealed that penetration of erythromycin into less accessible sites was more likely to be higher after intravenous administration than after intramuscular administration.     

Subcutaneously implanted tissue chambers — a pharmacokinetic study

The purpose of this study was to characterize the pharmacokinetics of a subcutaneously implanted tissue-chamber model. Thermoplastic tissue chambers were implanted in the paralumbar fossae of six steers. Starting 30 days after implantation, the distribution of intravenously administered antipyrine and phenylbutazone into the tissue chambers was studied. These pharmacokinetic experiments were repeated 10 days later to determine the effect of time after implantation on tissue-chamber distribution. Fifty days after implantation, tissue chambers were drained of transudate, refilled with sterile saline and the rate of influx of endogenous urea, creatinine and albumin was measured. Delayed diffusion of antipyrine and phenylbutazone into tissue chambers was well described using a compartmental model in which tissue-chamber fluid represented the third of three compartments arranged in series. The distribution of antipyrine into tissue chambers was greater than that of phenylbutazone; an observation which is well correlated with the high degree of protein binding of phenylbutazone. There was no effect of time on the penetration of the two agents. Rapid diffusion of urea and creatinine and extremely slow influx of albumin into chambers showed that these chambers formed true interstitial compartments.     

Response of Pasteurella haemolytica to erythromycin and dexamethasone in calves with established infection.

A subcutaneous soft tissue infection model in calves was used to study the in vivo response of Pasteurella haemolytica to erythromycin and dexamethasone. Two tissue chambers were implanted SC in each of 12 calves. At 45 days after implantation, all tissue chambers were inoculated with an erythromycin-sensitive strain of P haemolytica. Starting 24 hours after inoculation, calves were allotted to 4 groups of equal size and a 2 x 2-factorial arrangement of treatments was applied: 3 calves were given erythromycin (30 mg/kg of body weight, IM, for 5 days), 3 calves were given dexamethasone (0.05 mg/kg, IM, for 2 days), 3 calves were given erythromycin and dexamethasone, and the remaining calves served as nontreated controls. Chamber fluids were tested daily, and the response to treatment was measured. Neither erythromycin nor dexamethasone affected viability or growth of bacteria within tissue chambers. Dexamethasone had no effect on the influx of neutrophils into infected chambers. Despite repeated administration of a high dose of erythromycin and attainment of adequate concentration in serum, erythromycin concentration in chamber fluids did not exceed the minimal inhibitory concentration established in vitro. These results indicate that the clinical efficacy of erythromycin against P haemolytica sequestered in consolidated pneumonic lesions may not be well correlated with predictions based on serum pharmacokinetic and in vitro susceptibility data.     

Characterization of a soft-tissue infection model in the horse and its response to intravenoiis cephapirin administration

A soft-tissue infection model was created in eight horses by infecting subcutaneous tissue chambers with Streptococcus zooepidemicus organisms. Responses of the horses to the infections were determined by monitoring changes in the complete blood count and body temperature and by following changes in the cytology and protein content of the tissue chambers. Systemic reactions to the infections included a mild neutrophilia, mild pyrexia and mild anemia. There was a marked influx of neutrophils and protein into the chambers after they were seeded with bacteria and chamber neutrophil viability decreased markedly at the height of the infection. Subsequent to establishing tissue chamber infections four of the horses were treated with intravenous cephapirin t.d. at a dosage of 20 mg/kg for 5 days. Quantitative culturing of tissue chamber fluid was performed to analyze the efficacy of cephapirin therapy. Cephapirin therapy was accompanied by decreases in the systemic neutrophilia, pyrexia, anemia, and chamber bacterial counts. However, cephapirin did not eliminate the infection in any of the chambers. Chamber neutrophil viability was markedly increased during the cephapirin therapy period.     

Characterization of a sterile soft-tissue inflammation model in Thoroughbred horses

This paper describes the use of subcutaneously-placed tissue chambers as a sterile soft-tissue inflammation model in Thoroughbred horses. Acute, nonimmune inflammation was initiated by injecting a sterile lambda carrageenan solution into a tissue chamber. This model was used to study the temporal changes in oxygen and carbon dioxide tensions, pH, bicarbonate, protein, albumin, prostaglandin E₂ (PGE₂) and leukotriene B₄ (LTB₄) concentrations, cell counts and differential counts in tissue fluid from inflamed tissue chambers and control chambers. Skin temperatures over control and inflamed chambers were also compared. Carrageenan-induced inflammation resulted in significant increases in tissue-fluid carbon dioxide tension, leucocyte count, albumin, and PGE₂ and LTB₄ concentrations. It also resulted in a significant decrease in tissue fluid pH and HCO₃- concentration. Inflammation did not result in significant changes in tissue-fluid protein concentration, differential cell counts or skin temperature over the chambers. The use of this type of tissue chamber is wellsuited for studying the pathophysiology of a self-contained, non-immune inflammatory process. The model described in this paper could prove to be very useful in studies of the distribution of anti-inflammatory drugs and the effects of such drugs on various aspects of the inflammatory process.     

The Effect of Cimetidine and Aminoguanidine on Pro-inflammatory Cytokines in the Horse

In this study, six horses each had three subcutaneous tissue chambers. Each horse was pretreated with intravenous saline (control), cimetidine, or aminoguanidine with a 4-week washout period. On day 0, a carrageenan (NaCl inflamed) was instilled in 1 tissue chamber. Blood and all tissue chamber fluids were sampled on days -1 to 3 and measured for activity levels of tumor necrosis factor (TNF)-α, interleukin (IL)-1, and IL-6. The T_max for all cytokines (TNF-α, IL-1, IL-6) was 0.5 and 1 day post-inflammation in tissue chamber fluid. In the tissue chamber fluid, NaCl inflamed (NaCl-I), cimetidine, and aminoguanidine groups showed significant increases in IL-1 production. In the NaCl-I and cimetidine, tissue chamber fluid IL-6 was significantly increased when compared with NaCl noninflamed (NaCl-N) for the periods of study -1 to 1, -1 to 2, and -1 to 3. The cimetidine tissue chamber fluid [TCF] appeared to have a delayed, but greater, IL-6 response than the NaCl-I treatment. Even with cimetidine and aminoguanidine pretreatment, the resulting decrease in NO production demonstrated in our previously reported results in these same animals appeared to be too late to decrease the early cytokine response. However, it may assist in preventing the subsequent NO-induced upregulation of pro-inflammatory cytokine production.     

Radioimmunoassay of the anabolic agent zeranol. V. Residues of zeranol in the edible tissues, urine, faeces and bile of steers treated with Ralgro

Two trials were conducted on steers implanted with zeranol (Ralgro) to determine the edible tissue residues and the secretion pattern in faeces, urine and bile of zeranol residues throughout and beyond the recommended withdrawal period (70 days) for this drug. In the first trial there was considerable variation in the zeranol residue concentration in all edible tissues, the highest concentrations found in the liver being significantly above the control values (P less than 0.05). In the other tissues, only fat sampled 14 days after implanting was significantly above the control value (P less than 0.05). The zeranol concentration in bile samples obtained at slaughter [70 days (18), 90 days (5) and 120 days (2)] were all higher than the apparent concentration in the bile of untreated steers. The mean concentration of zeranol in the faeces and urine varied from day to day and between animals sampled on the same day following implantation. The highest mean concentrations were observed during the first 40 days following implanting, declining steadily to approach the control values 70 days after implantation. The second trial using steers prepared with bile duct re-entrant cannulae resulted in a similar pattern of zeranol excretion in bile, faeces and urine. The highest concentrations of zeranol were observed in bile and ranged from 24 to 34 micrograms/l; there was considerable variation between animals and within animals sampled on successive days. Although the concentration declined steadily, zeranol was still readily detectable 120 days after implanting.(ABSTRACT TRUNCATED AT 250 WORDS)     

Maintenance of physiologic concentrations of plasma testosterone in the castrated male dog, using testosterone-filled polydimethylsiloxane capsules.

Effects of various numbers of polydimethylsiloxane (PDS) capsules filled with testosterone (PDS-T) on plasma testosterone (PT) in castrated male dogs were studied. Dogs were implanted with 1 empty PDS capsule or 1, 3, or 5 PDS-T capsules. Blood samples were collected prior to and after implantation, after castration with capsules in situ, and after capsule removal. The PT was determined in these samples by radioimmunoassay. One empty capsule had no effect on PT concentration; after castration, PT values fell to nondetectable amounts. One PDS-T capsule maintained PT at concentrations above nondetectable amounts after castration, but these concentrations were significantly (P less than 0.05) lower than were preimplantation values. Three or five PDS-T capsules were capable of maintaining PT concentrations in the castrated male dog similar to those concentrations seen in the intact dog.     

Amniotic and allantoic fluids from experimentally infected sheep contain immunoglobulin specific for Chlamydophila abortus

Chlamydophila abortus, the aetiological agent of enzootic abortion of ewes (EAE), replicates in trophoblast cells leading to their destruction and dissemination of the bacterium to foetal organs. To further understand the pathogenesis of EAE, amniotic and allantoic fluids were collected from experimentally infected pregnant ewes at 30 (7 samples from each fluid), 35 (8 samples from each fluid), 40 (10 samples from each fluid) and 43 (6 amniotic fluids and 7 allantoic fluids) days post-infection to determine pathogen numbers and other markers of infection. Whilst experimentally infected ewes had characteristic placental lesions, only two amniotic and seven allantoic fluid samples were positive for C. abortus by real-time PCR. In contrast, all amniotic and allantoic fluids were positive for immunoglobulin. Immunoglobulins were generally detected earlier in allantoic fluid than in amniotic fluid and the numbers of samples containing immunoglobulins increased as infection progressed. IgG in amniotic and allantoic fluids was shown to be specific for C. abortus, and reacted with the major outer membrane proteins, polymorphic outer membrane protein and macrophage infectivity potentiator protein. A comparison of two-dimensional immunoblots using purified IgG from the allantoic fluid, amniotic fluid, ewe serum and foetal serum of a C. abortus infected animal at 40 days post infection indicated a pattern of reactivity intermediate between that of the ewe serum and the foetal serum. Results suggest that a maternal source of immunoglobulin is predominant at 30 days post-infection but that foetal derived antibodies may be contributed at a later stage.     

Effect of monensin withdrawal on rumen fermentation,methanogenesis and microbial populations in cattle

This study was designed to obtain information on the residual influence of dietary monensin on ruminant fermentation, methanogenesis and bacterial population. Three ruminally cannulated crossbreed heifers (14 months old, 363 ± 11 kg) were fed Italian ryegrass straw and concentrate supplemented with monensin for 21 days before sampling. Rumen fluid samples were collected for analysis of short chain fatty acid (SCFA) profiles, monensin concentration, methanogens and rumen bacterial density. Post‐feeding rumen fluid was also collected to determine in vitro gas production. Monensin was eliminated from the rumen fluid within 3 days. The composition of SCFA varied after elimination of monensin, while total production of SCFA was 1.78 times higher than on the first day. Methane production increased 7 days after monensin administration ceased, whereas hydrogen production decreased. The methanogens and rumen bacterial copy numbers were unaffected by the withdrawal of monensin.     

Tissue chamber model of acute inflammation in farm animal species

A tissue chamber model of acute inflammation for use in comparative studies in calves, sheep, goats and pigs has been established and validated. Tissue chambers were prepared from silicon rubber tubing, of inner diameter 12.7 mm, length 115 mm and volume 15 ml, with 10 holes, each of 6mm diameter, at each end. In each animal two or four chambers were inserted at subcutaneous sites. Six weeks after implantation an acute inflammatory reaction in a single cage was generated by the intracaveal injection of 0.5 ml of 1% carrageenan solution. Serial samples of exudate (injected chamber), transudate (non-injected chamber) and blood were collected for measurement of exudate and transudate leucocyte count, prostaglandin (PG)E(2) concentration in exudate and serum thromboxane (Tx)B(2) concentration. In addition, skin temperature changes over exudate and transudate chambers were recorded. In all four species, carrageenan induced an acute inflammatory response, indicated by increases to peak values followed by return towards baseline in skin temperature, leucocyte count and PGE(2) concentration. For each of these variables in calves, sheep and goats the increases were significantly greater for exudate than for transudate. The degree of intra-species variation in each variable was acceptable. Marked inter-species differences were recorded: skin temperature rise was greatest in calves and least in sheep and goats; exudate PGE(2) concentration was increased in the order sheep>goat>pig>calf; serum TxB(2) concentration was increased in the order calf>goat>sheep>pig and exudate leucocyte count was increased to a greater extent in the pig than in the three ruminant species. The model has advantages over some previously described tissue chamber models of inflammation and will be suitable for use in comparative studies of inflammatory mechanisms and the pharmacokinetics and pharmacodynamics of anti-inflammatory drugs.     

Bronchogenic cyst in a German shepherd dog

Intermittent episodes of fever, severe dyspnoea and cyanosis were observed in a two-and-a-half-year-old male German shepherd dog. The clinical signs were of sudden onset but disappeared within eight hours, in five almost identical episodes over a period of 40 days. Radiological examination of the thorax revealed a large rounded area of radiolucency surrounded by a thin radiopaque structure. The lesion increased in volume between examinations, but otherwise remained similar in appearance. It could not be confirmed from the radiographs whether the structure was situated in lung tissue or mediastinum. Bronchoscopic examination revealed no abnormal findings and there was no bacterial growth from samples taken 30 days after the onset of symptoms. A large, vesicular structure, partly adherent to the mediastinum, was surgically removed from the left cranial lung lobe. The structure was 8 to 10 cm in diameter and partly filled with mucoid pink fluid. Histological examination revealed that the wall contained traces of bronchial epithelial cells. On bacteriological examination of the fluid, Gram-positive, mucus-forming bacteria were present. The definitive gross pathological and histopathological diagnosis was a bronchogenic cyst which had developed secondarily to bronchiectasis. Bronchitis and peribronchitis were also identified. The dog recovered well after surgery and, at the time of writing, was in active duty as a police dog, showing no signs of respiratory illness.     

Effect of low-temperature drying on the nitrogenous compounds and inositol phosphates in broiler chickens and cecectomized laying hen excreta

We investigated how the chemical composition of broiler chicken and cecectomized laying hen excreta is affected by drying in a forced-air drying chamber at low temperatures. Excreta that was immediately frozen after voiding provided the reference values. The excreta were dried in drying chambers for 4 hr, 6 hr, and 12 hr at 23°C or 33°C in the broiler experiment and 19°C or 29°C in the cecectomized laying hen experiment. The total N and inositol phosphate concentrations in the excreta of broiler chickens and cecectomized laying hens were not influenced (p > .050), except for one inositol tetrakisphosphate isomer (p = .026) in broilers. Compared to fresh excreta, drying did not affect the ammonia concentrations in the cecectomized laying hen experiment (p > .050), but the ammonia concentration was lower when dried for 12 hr at 33°C in the broiler experiment (p = .002). Amino acid concentrations in cecectomized laying hen excreta decreased until 4 hr of drying and then increased at both drying temperatures (p < .001). The results indicate that the applicability of drying poultry excreta at low temperatures in forced-air drying chambers to determine the chemical compound concentrations is trait-dependent. Future studies are necessary to investigate whether these results are also dependent upon the amount of excreta stored in the drying chambers.     

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 of Narthecium ossifragum collected from eight sites in M?re 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 of C. 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.