Natural occurrence of deoxynivalenol, 15-acetyl-deoxynivalenol, and zearalenone in refusal factor corn stored since 1972.

Two samples of "refusal factor" corn, one stored frozen in Minnesota and one stored dry in Indiana since 1972 or 1973, were analyzed for the presence of Fusarium spp. and Fusarium toxins. Both samples were from corn refused by swine in Indiana from 1972 to 1973. Sample FS 808 (stored in Indiana) contained 20 ppm of deoxynivalenol (20 micrograms/g), 16 ppm of 15-acetyl-deoxynivalenol, 5 ppm of zearalenone, and 0.2 ppm of alpha-zearalenol. Sample FS 362 (stored in Minnesota) contained 3 ppm of deoxynivalenol, 1 ppm of 15-acetyldeoxynivalenol, and 0.3 ppm of zearalenone. The presence of 15-acetyl-deoxynivalenol is significant because it is the first report of it occurring naturally in refusal factor corn, and it may account in part for the refusal that could not be solely attributed to deoxynivalenol.     

Natural occurrence of deoxynivalenol, 15-acetyl-deoxynivalenol, and zearalenone in refusal factor corn stored since 1972

Two samples of "refusal factor" corn, one stored frozen in Minnesota and one stored dry in Indiana since 1972 or 1973, were analyzed for the presence of Fusarium spp. and Fusarium toxins. Both samples were from corn refused by swine in Indiana from 1972 to 1973. Sample FS 808 (stored in Indiana) contained 20 ppm of deoxynivalenol (20 micrograms/g), 16 ppm of 15-acetyl-deoxynivalenol, 5 ppm of zearalenone, and 0.2 ppm of alpha-zearalenol. Sample FS 362 (stored in Minnesota) contained 3 ppm of deoxynivalenol, 1 ppm of 15-acetyldeoxynivalenol, and 0.3 ppm of zearalenone. The presence of 15-acetyl-deoxynivalenol is significant because it is the first report of it occurring naturally in refusal factor corn, and it may account in part for the refusal that could not be solely attributed to deoxynivalenol.     

Characterization of fumonisin toxicity in orally and intravenously dosed swine

Fumonisin B₁ (FB₁), a recently identified mycotoxin produced by Fusarium moniliforme in corn, has been shown to cause death in swine due to pulmonary edema, an apparently species specific effect, and to interfere with sphingolipid metabolism in vitro. Here we characterize the toxicity of fumonisins, using female cross-bred swine weighing 6 to 13 kg, and present a hypothesis regarding the mechanism of fumonisin-induced pulmonary edema in swine. FB₁ was given daily intravenously (IV) to pig 1 for 9 days for a total of 72 mg (7.9 mg/kg) and to pig 2 for 4 days for a total of 67 mg (4.6 mg/kg). Pig 3 (control) was given saline IV for 9 days. Corn screenings naturally contaminated with FB₁ (166 ppm) and FB₂ (48 ppm) were fed to pigs 4, 5, and 6, and ground corn was fed to pigs 7 and 8 (controls). Pigs 4 and 7 were killed on day 5; pig 5 was found dead on day 6; and pigs 6 and 8 were killed on day 15. Pigs 4 and 5 had ingested 187 and 176 mg total fumonisins, respectively, while pig 6 had ingested 645 mg. Feed consumption had decreased in pigs fed corn screenings, with an additional sharp decrease prior to onset of clinical signs. Increases in serum liver enzymes, total bilirubin, and cholesterol were present, but electrocardiograms, heart rate, and body temperature were unaffected. Pigs dosed IV with FB₁, developed mild intermittent respiratory abnormalities, while those fed screenings developed respiratory distress within 5 days. Mild interstitial pulmonary edema was observed in pig 1. Severe interstitial pulmonary edema, pleural effusion, and increased lung wet/dry weight ratio were observed in pigs 4 and 5. All pigs given fumonisin (either IV or orally) had hepatic changes characterized by hepatocyte disorganization and necrosis; pancreatic acinar cell degeneration was also observed. Ultrastructural changes in orally dosed swine included loss of sinusoidal hepatocyte microvilli; membranous material in hepatic sinusoids; and multilamellar bodies in hepatocytes, Kupffer cells, pancreatic acinar cells and pulmonary macrophages. Pulmonary intravascular macrophages (PIMs) contained large amounts of membranous material. Thus, the target organs of fumonisin in the pig are the lung, liver, and pancreas. At lower doses, slowly progressive hepatic disease is the most prominent feature, while at higher doses, acute pulmonary edema is superimposed on hepatic injury and may cause death. We hypothesize that altered sphingolipid metabolism causes hepatocellular damage resulting in release of membranous material into the circulation. This material is phagocytosed by the PIMs thus triggering the release of mediators which ultimately results in pulmonary edema.Presented in part at the 1991 Annual Meeting of the Society of Toxicology. The Toxicologist 11: 143 (A499).     

Effect of deoxynivalenol (vomitoxin) on fertility, pregnancy, and postnatal development of Sprague-Dawley rats

A diet containing 20 ppm (micrograms/g) of purified deoxynivalenol (DON) was fed to male and female Sprague-Dawley rats for 60 and 15 days, respectively, before breeding. Rats consuming feed amended with DON throughout pregnancy and lactation showed no clinical signs of toxicity, nor did the control or pair-fed control groups. Male rats in the DON treatment group showed no feed refusal but were less efficient than males in control groups in converting feed into body mass. Feed refusal in female rats varied with stage of pregnancy. Before breeding, overall feed consumption was similar in all groups, but in the DON treatment group there was significant feed refusal for the first 2 days. Feed conversion efficiency was reduced in the DON treatment group. Pregnant and lactating rats fed DON-treated feed ate 6% less than did control rats fed solvent-treated feed. Although pair-fed control rats ate 14 to 21% less than rats in the DON treatment group, their body weights were greater than those of the DON group rats throughout most of the feeding trials, indicating that DON has a toxic effect. Only 50% of the matings between DON group rats resulted in pregnancy, compared with 80% in the control groups. There were no differences detected among groups in ratio of male to female pups, survival rate, or average litter number and weight. Pup weight gains in all groups were comparable through postnatal day 14.(ABSTRACT TRUNCATED AT 250 WORDS)     

Effect of deoxynivalenol (vomitoxin) on fertility, pregnancy, and postnatal development of Sprague-Dawley rats.

A diet containing 20 ppm (micrograms/g) of purified deoxynivalenol (DON) was fed to male and female Sprague-Dawley rats for 60 and 15 days, respectively, before breeding. Rats consuming feed amended with DON throughout pregnancy and lactation showed no clinical signs of toxicity, nor did the control or pair-fed control groups. Male rats in the DON treatment group showed no feed refusal but were less efficient than males in control groups in converting feed into body mass. Feed refusal in female rats varied with stage of pregnancy. Before breeding, overall feed consumption was similar in all groups, but in the DON treatment group there was significant feed refusal for the first 2 days. Feed conversion efficiency was reduced in the DON treatment group. Pregnant and lactating rats fed DON-treated feed ate 6% less than did control rats fed solvent-treated feed. Although pair-fed control rats ate 14 to 21% less than rats in the DON treatment group, their body weights were greater than those of the DON group rats throughout most of the feeding trials, indicating that DON has a toxic effect. Only 50% of the matings between DON group rats resulted in pregnancy, compared with 80% in the control groups. There were no differences detected among groups in ratio of male to female pups, survival rate, or average litter number and weight. Pup weight gains in all groups were comparable through postnatal day 14.(ABSTRACT TRUNCATED AT 250 WORDS)     

Metabolisierung von Deoxynivalenol beim Schwein: Bestimmung von DON und DOM-1 im Urin vom Schwein

This paper describes a feeding study with 7 pigs, which were fed with deoxynivalenol contaminated oats at a level of 0.23 mg/kg body mass/day over 16 experiment days. The contamination level of consumed feed was 14.4 mg DON/kg in the ration. The parallel control group of 7 pigs were fed with DON free oats. Urine samples were taken each two days. The content of DON and DOM-1 (de-epoxy deoxynivalenol) in urine was determined. The mean concentration of DON in urine of animals in trial group was 580 μg/l, whereas DOM-1 32 μg/l.     

Co-occurrence of mycotoxins in swine feed produced in Portugal

A total of 404 samples of commercial swine feed from Portugal feed mills were analysed by HPLC methods for the presence of mycotoxins: 277 samples of feed for fattening pigs were analysed for ochratoxin A (OTA), zearalenone (ZEA), and deoxynivalenol (DON), and 127 samples of feed for sows were analysed for ZEA and fumonisins (FB₁ + FB₂). Concerning feed for fattening pigs, 21 (7.6%) samples were positive for OTA, (2–6.8 μg/kg), 69 (24.9%) were positive for ZEA (5–73 μg/kg), and 47 (16.9%) were positive for DON (100–864 μg/kg). In feed for sows, the results showed 29.9% of positive samples for ZEA (5–57.7 μg/kg) and 8.7% positive samples for FB₁ and FB₂ (50–391.4 μg/kg). Co-occurrence of DON/ZEA was found most frequently, but simultaneous contamination with OTA/ZEA and OTA/DON was also found.     

Lupin-seed meal (Lupinus albus cv. Hamburg) as a source of protein for growing pigs

Two experiments were performed to evaluate Lupinus albus cv. Hamburg as a source of protein for growing pigs. The first was in a factorial design, involving two levels of feeding (restricted and ad libitum) and five isocaloric, isonitrogenous diets (0, 10.3, 20.7 and 31% Hamburg, and 31% Hamburg supplemented with 0.20% synthetic L-lysine). The growth performance of pigs from 22 to 70 kg live weight was unaffected by 10.3% Hamburg replacing soya-bean meal and meat and bone meal, but at higher levels both growth rate and feed conversion efficiency were significantly depressed. Feed intake was not significantly affected by the level of Hamburg, but dressing percentage decreased significantly from 84.3 to 80.2% as the proportion of Hamburg was increased from 0 to 31%. The addition of synthetic lysine to the 31% Hamburg diet improved feed conversion efficiency, but not to the level of the diet containing no Hamburg.Hamburg contained 2100 mg/kg manganese and the effects of levels of manganese from 72 to 1330 mg/kg on pig performance between 20 and 55 kg live weight were studied in the second experiment. Up to 1330 mg/kg manganese in the diet did not affect the growth performance or carcass quality of pigs. In both experiments, the growth performance of pigs given 31 or 33% Hamburg diets, each supplemented with 0.20% synthetic L-lysine, was lower than that of pigs receiving diets without Hamburg.The digestible energy content and alkaloid content of Hamburg were 18.2 (SE ± 0.38) MJ/kg dry matter and 0.018%, respectively.     

Microbial transformation of deoxynivalenol (vomitoxin).

Microbial inocula from rumen fluid, soil, and contents of the large intestines of chickens (CLIC) and of swine (SLIC) were tested for their ability to transform deoxynivalenol (vomitoxin) in vitro. Microorganisms in (CLIC) completely transformed pure vomitoxin, and this activity was retained through six serial subcultures. No alteration of the toxin by incubation with SLIC was detected, whereas 35% of the vomitoxin was metabolized in the original culture of rumen fluid and 50% was metabolized by the soil sample, though metabolism was decreased in subsequent subcultures of either sample. A single metabolite was isolated and identified as deepoxy vomitoxin. The increase in concentration of deepoxy vomitoxin in the culture medium corresponded with the decrease in vomitoxin concentration. The vomitoxin transformation rate was not affected by either the ratio of CLIC to vomitoxin (5 to 0.2 g of CLIC per mg of vomitoxin) or the initial concentration of vomitoxin (14 to 1,400 ppm) in the medium. Biotransformation of vomitoxin was completely inhibited when the pH in the medium was lowered to 5.20. Sodium azide at a 0.1% (wt/vol) concentration in the medium blocked the transformation of vomitoxin, suggesting that the deepoxidation of vomitoxin is an energy-dependent process. About 50% of the vomitoxin in moldy corn in culture medium was transformed by microorganisms from CLIC. The vomitoxin transformation rate in moldy corn was not affected when the concentration of CLIC changed from 0.2 to 0.8 g/ml of medium. Vomitoxin in the moldy corn was not transformed when CLIC were added to corn without culture medium.(ABSTRACT TRUNCATED AT 250 WORDS)     

Effect of avilamycin and tylosin on the metabolizable energy in growing and finishing pigs

In two metabolism trials with growing and finishing pigs the influence of the antibiotic feed additives Avilamycin and Tylosin on the metabolizable energy was investigated at different levels of dietary protein content. In the first experiment (growing pigs) the antibiotics were supplied at levels of 0 mg/kg, 40 mg/kg Avilamycin and 40 mg/kg Tylosin to diets containing 18.5%, 17.5%, 16.5% and 14.0% of crude protein. In the second experiment (finishing pigs) 0 mg/kg antibiotics, 20 mg/kg Avilamycin and 20 mg/kg Tylosin were used in diets containing 16.5% and 14.0% of crude protein. The body weight of the animals averaged 46 kg (growing pigs) and 68 kg (finishing pigs).

In growing pigs the supplementation of Tylosin increased the digestibility of dry matter and energy at 1 percentage unit each, while in finishing pigs no effects were observed. Since the urinary energy excretion was not affected by antibiotics, there was only in Tylosin treated growing pigs a slight rise in dietary contents of metabolizable energy by 1.6%. The reduction of the dietary protein content resulted in increased digestibility of dry matter and energy, reduced urinary energy excretions and increased dietary contents of metabolizable energy.     

Microbial transformation of deoxynivalenol (vomitoxin).

Microbial inocula from rumen fluid, soil, and contents of the large intestines of chickens (CLIC) and of swine (SLIC) were tested for their ability to transform deoxynivalenol (vomitoxin) in vitro. Microorganisms in (CLIC) completely transformed pure vomitoxin, and this activity was retained through six serial subcultures. No alteration of the toxin by incubation with SLIC was detected, whereas 35% of the vomitoxin was metabolized in the original culture of rumen fluid and 50% was metabolized by the soil sample, though metabolism was decreased in subsequent subcultures of either sample. A single metabolite was isolated and identified as deepoxy vomitoxin. The increase in concentration of deepoxy vomitoxin in the culture medium corresponded with the decrease in vomitoxin concentration. The vomitoxin transformation rate was not affected by either the ratio of CLIC to vomitoxin (5 to 0.2 g of CLIC per mg of vomitoxin) or the initial concentration of vomitoxin (14 to 1,400 ppm) in the medium. Biotransformation of vomitoxin was completely inhibited when the pH in the medium was lowered to 5.20. Sodium azide at a 0.1% (wt/vol) concentration in the medium blocked the transformation of vomitoxin, suggesting that the deepoxidation of vomitoxin is an energy-dependent process. About 50% of the vomitoxin in moldy corn in culture medium was transformed by microorganisms from CLIC. The vomitoxin transformation rate in moldy corn was not affected when the concentration of CLIC changed from 0.2 to 0.8 g/ml of medium. Vomitoxin in the moldy corn was not transformed when CLIC were added to corn without culture medium.(ABSTRACT TRUNCATED AT 250 WORDS)     

Research note: Effects of deoxynivalenol on immunohistological parameters in pigs

TheFusarium toxin deoxynivalenol (DON) is known to exert immunomodulatory effects. Numerous studies in mice demonstrated that dietary exposure leads to an upregulation of polymeric serum immunoglobulin A (IgA) suggesting the mucosal immune system as a primary target while at the cellular level T cells and macrophages are involved in this process. The present study aimed to verify these effects in pigs. A total of 24 male pigs were subjected to four treatments, a control group fed a diet devoid of DON, a chronically exposed group receiving a diet containing contaminated wheat (5.7 mg DON/kg diet), an acute orally exposed group receiving only one meal (550 g) of the contaminated feed and an acute intravenous exposed group receiving 53 μg DON/kg body weight. Cryosections of the spleen and the jejunum of the pigs were immunohistologically stained for IgA+, CD3+, CD4+ and CD8+ cells. The number of positive stained cells did not differ significantly between the treatment groups and the control group of any of the specimen.     

Effect of high dietary copper on weight gain and neuropeptide Y level in the hypothalamus of pigs

An experiment was performed to examine the effect of dietary copper supplementation on weight gain, neuropeptide Y (NPY) concentration and NPY mRNA expression level in the hypothalamus of pigs. Forty-five crossbred pigs were randomly assigned to three groups of 15 pigs, each comprising five replicates of 3 animals. Pigs were allocated to diets that contained 10 mg/kg (as a control), 125 and 250 mg/kg copper as CuSO₄. Live weight gain and feed conversion efficiency was determined at the end of the experiment and five pigs, selected at random from each group, were slaughtered and the hypothalami collected for determination of NPY concentration and NPY mRNA expression level. The results showed that average daily gain (ADG) and average daily feed intake (ADFI) were higher and feed:gain (F:G) ratio was lower in pigs fed the diets with 125 and 250 mg/kg copper (P<0.05), respectively, than in pigs fed a diet with 10 mg/kg copper, but that there was no statistically significant difference in growth performance between animals of the 125 mg/kg and the 250 mg/kg copper groups. Furthermore, pigs fed diets with 125 and 250 mg/kg copper had higher NPY concentrations and NPY mRNA expression levels in their hypothalamus than control animals. The data indicated that 125 and 250 mg/kg copper gave similar responses in terms of weight gain, whilst high dietary copper could enhance NPY concentration and NPY mRNA expression level in the hypothalamus of pigs. High dietary copper appears to increase feed intake and promote weight gain by enhancing NPY concentration and NPY mRNA expression level in the hypothalamus of pigs.     

Macleaya cordata extract and Sangrovit genotoxicity. Assessment in vivo

Background: Sanguinarine (SG) has been reported to form DNA adducts in vitro and increase the levels of DNA single strand breaks in the blood and bone marrow of mice treated intraperitoneally with SG. Recently, we showed no genotoxic effects of orally administrated 120 mg/kg feed Macleaya cordata extract (a mixture of sanguinarine and chelerythrine) in pigs or rats in 90-day studies. The goal of this paper was to assess the possible genotoxicity of M. cordata extract when included as a dietary admixture to rodents at concentrations providing 600 mg/kg feed and 100, 7000 or 14000 mg/kg feed Sangrovit (natural feed additive containing M. cordata extract and powdered M. cordata) in a 90-day pilot study. Methods and Results: The rats consumed ad libitum either the standard diet or the diets containing 367 ppm of sanguinarine and chelerythrine in M. cordata extract, and 5, 330, or 660 ppm of total alkaloids in Sangrovit for 90 days. The DNA adducts formation in liver was analyzed by (32)P-postlabeling technique and DNA single strand breaks in lymphocytes were evaluated by Comet assay. The results showed that M. cordata extract and/or Sangrovit induced no DNA damage to rat lymphocytes or hepatocytes after 90-days oral administration. Conclusions: Data from the studies described in this paper and the fact that Sangrovit given to the rats in our experiments were higher than the recommended dose (50 to 100 mg/kg feed), argue strongly in favour of the use of Sangrovit in live stock.     

Developmental toxicity evaluation of berberine in rats and mice

BACKGROUND: Berberine, a plant alkaloid, is found in some herbal teas and health-related products. It is a component of goldenseal, an herbal supplement. Berberine chloride dihydrate (BCD) was evaluated for developmental toxicity in rats and mice. METHODS: Berberine chloride dihydrate was administered in the feed to timed-mated Sprague-Dawley (CD) rats (0, 3,625, 7,250, or 14,500 ppm; on gestational days [GD] 6-20), and Swiss Albino (CD-1) mice (0, 3,500, 5,250, or 7,000 ppm; on GD 6-17). Ingested doses were 0, 282, 531, and 1,313 mg/kg/day (rats) and 0, 569, 841, and 1,155 mg/kg/day (mice). RESULTS: There were no maternal deaths. The rat maternal lowest observed adverse effect level (LOAEL), based on reduced maternal weight gain, was 7,250 ppm. The rat developmental toxicity LOAEL, based on reduced fetal body weight per litter, was 14,500 ppm. In the mouse study, equivocal maternal and developmental toxicity LOAELs were 5,250 ppm. Due to scattering of feed in the high dose groups, a gavage study at 1,000 mg/kg/day was conducted in both species. CONCLUSIONS: In rats, maternal, but not fetal adverse effects were noted. The maternal toxicity LOAEL remained at 7,250 ppm (531 mg/kg/day) based on the feed study and the developmental toxicity NOAEL was raised to 1,000 mg/kg/day BCD based on the gavage study. In the mouse, 33% of the treated females died. Surviving animals had increased relative water intake, and average fetal body weight per litter decreased 5-6% with no change in live litter size. The maternal toxicity LOAEL remained at 5,250 ppm (841 mg/kg/day) BCD, based on increased water consumption. The developmental toxicity LOAEL was raised to 1,000 mg/kg/day BCD based on decreased fetal body weight.     

Practically relevant concentrations of deoxynivalenol in diets for growing-finishing pigs offered as mash or pellets

A complete 2 x 3 two factorial design was applied to investigate the effects of Fusarium-infected wheat (2.5 mg DON/kg, 0, 25 and 50% of the diets), feed processing (mash and pellets) and the interactions thereof on fattening pigs (96, n= 16/group). Feed-to-gain ratio was significantly increased by contaminated wheat (2.65; 2.62 and 2.73 kg/kg for diets containing 0, 25 and 50% Fusarium-infected wheat, respectively) while digestibility of nutrients and metabolizable energy were not affected by the wheat batch. The feed processing also resulted in significant differences in feed-to-gain ratio but was accompanied by significant effects on the digestibility of organic matter and crude fat and on the metabolizable energy. Clinical chemical parameters were not significantly altered by the inclusion of the infected wheat. The lymphocyte proliferation capacity was not significantly affected by any of the experimental factors. A contribution of the feed processing to the variation of the deoxynivalenol (DON) effect may not be deduced from the present results.     

High Lever Dietary Copper Promote Ghrelin Gene Expression in the Fundic Gland of Growing Pigs

This experiment was conducted to examine the effect of dietary copper supplementation on ghrelin mRNA expression level in the fundic gland of growing pigs. A total of 45 crossbred pigs were randomly assigned to three groups of 15 pigs, five replicates of three animals comprised each group. Pigs were allocated to diets that contained 5?mg/kg copper (as the control group), 125?mg/kg copper sulfate, or 125?mg/kg copper methionine. At the end of the experiment, five pigs were selected at random from each group, slaughtered, and collected the fundic gland for determination of ghrelin mRNA expression level. The results showed that average daily gain, average daily feed intake, absolute weight, serum growth hormone (GH) concentration, and ghrelin mRNA level were higher in pigs fed the diets with 125?mg/kg copper methionine and 125?mg/kg copper sulfate (P?<?0.05), than in pigs fed a diet with 5?mg/kg copper. These data suggest that high dietary copper (125?mg/kg) appears to increase feed intake and promote weight gain by enhancing the secretion of GH and ghrelin mRNA level in growing pigs.     

Clinical cases of fusarium-toxicoses in Austrian domestic animals in connection with fusariumtoxinrcontaminated feedstuffs

A surveillance study of the most important fusarium-toxins in Austrian feed samples, the estrogenic mycotoxin zearalenone (F-2 toxin) as well as the refusal of feed causing deoxynivalenol (vomitoxin), of the last 8 years is given. The author describes predominantly the biologic effects in swine, cattle and poultry from the practical point of view and the correlation between clinical symptoms of the incriminated animals and the mycotoxin-levels found in the suspicious feed samples. Some field cases, the clinical symptoms and the fusariumtoxin-concentrations found are presented in one table.     

Sample clean-up methods,immunoaffinity chromatography and solid phase extraction,for determination of deoxynivalenol and deepoxy deoxynivalenol in swine serum

Concentrations of deoxynivalenol (DON) and deepoxy deoxynivalenol (DOM-1) in animal blood are important parameters for studies in toxicology and biological detoxification of DON. Clean-up methods, using either immunoaffinity chromatography (IAC) or solid phase extraction (SPE), were compared in order to determine the free form of DON or DOM-1 and the sum amount (free form plus glucuronide conjugated form of DON or DOM-1), respectively, in swine serum. Detection was achieved by high performance liquid chromatography with ultraviolet detection (HPLC-UV). Compared with the SPE-HPLC method, the IAC-HPLC method provided lower quantitation limit (DON: 18 vs 42 ng/ml; DOM-1: 21 vs 30 ng/ml) and higher recoveries (DON: 93.4–102.7% vs 63.7–85.3%; DOM-1: 85.5–91.1% vs 68.0–82.6%). Compared with previously published methods, the developed IAC-HPLC method removed analytical interferences from swine serum in one quick and easy step, and eliminated steps of extraction with organic solvent and/or pre-purification using SPE cartridges. This IAC-HPLC method was used to analyze swine serum samples collected from pigs that were evaluated in a feeding trial of a microbiological detoxification of DON. No DON or DOM-1 were detected in serum samples from pigs given a toxin-free diet or a microbial control diet. In serum samples from pigs given a DON diet (5 mg/kg of DON), free form DON and sum free DON + conjugated DON were 38.8 ± 13.7 and 49.8 ± 14.1 ng/ml, respectively. In serum samples from those given a detoxified-DON diet (DON was transformed to DOM-1), free form DOM-1 was detected but not quantified, and the sum DOM-1 was found as 47.5 ± 6.3 ng/ml.     

Modelling the time at which overcrowding and feed interruption emerge on the swine premises under movement restrictions during a classical swine fever outbreak

A stochastic risk model was developed to estimate the time elapsed before overcrowding (TOC) or feed interruption (TFI) emerged on the swine premises under movement restrictions during a classical swine fever (CSF) outbreak in Indiana, USA. Nursery (19 to 65 days of age) and grow-to-finish (40 to 165 days of age) pork production operations were modelled separately. Overcrowding was defined as the total weight of pigs on premises exceeding 100% to 115% of the maximum capacity of the premises, which was computed as the total weight of the pigs at harvest/transition age. Algorithms were developed to estimate age-specific weight of the pigs on premises and to compare the daily total weight of the pigs with the threshold weight defining overcrowding to flag the time when the total weight exceeded the threshold (i.e. when overcrowding occurred). To estimate TFI, an algorithm was constructed to model a swine producer’s decision to discontinue feed supply by incorporating the assumptions that a longer estimated epidemic duration, a longer time interval between the age of pigs at the onset of the outbreak and the harvest/transition age, or a longer progression of an ongoing outbreak would increase the probability of a producer’s decision to discontinue the feed supply. Adverse animal welfare conditions were modelled to emerge shortly after an interruption of feed supply. Simulations were run with 100 000 iterations each for a 365-day period. Overcrowding occurred in all simulated iterations, and feed interruption occurred in 30% of the iterations. The median (5th and 95th percentiles) TOC was 24 days (10, 43) in nursery operations and 78 days (26, 134) in grow-to-finish operations. Most feed interruptions, if they emerged, occurred within 15 days of an outbreak. The median (5th and 95th percentiles) time at which either overcrowding or feed interruption emerged was 19 days (4, 42) in nursery and 57 days (4, 130) in grow-to-finish operations. The study findings suggest that overcrowding and feed interruption could emerge early during a CSF outbreak among swine premises under movement restrictions. The outputs derived from the risk model could be used to estimate and evaluate associated mitigation strategies for alleviating adverse animal welfare conditions resulting from movement restrictions.