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Biomedical subjects

L F Kubena

Publications and source records attributed to L F Kubena.

At least 37 records · Page 2Linked to original sources

Isolation of Salmonella typhimurium Tn5 mutants defective for survival on egg shell surface using transposon footprinting.

The objective of this study was to screen the genome of Salmonella typhimurium for genes potentially required for survival on egg shell surfaces using a novel transposon footprinting method based on a previously developed Tn5 mutagenesis technique. Since the amplified DNA fragment length should usually be unique for each mutant, the polymerase chain reaction products separated on an agarose gel generate a transposon footprint with each band in the footprint representing the corresponding Tn5 mutant. By comparing the footprints from the pools of S. typhimurium Tn5 mutants before and after inoculation on egg shell surfaces, Tn5 mutants not recovered after selection were rapidly identified for potential isolation and genetic analysis.

Animals↗

Effect of storage condition on bone breaking strength and bone ash in laying hens at different stages in production cycles.

This study was conducted to determine the effects of refrigeration and frozen storage on tibia breaking strength (kg/g) and tibia ash (%) in bones obtained from hens of different ages. A total of 75 Single Comb White Leghorn hens were divided into three equal groups according to age (72, 80, and 92 wk of age). Both tibias of each hen were harvested and immediately defleshed. The tibias from each hen were randomly assigned to either 1 d of refrigeration or 7 d of frozen storage. Tibia breaking strengths were determined using an Instron Universal Testing Machine with 50-kg-load cell at 50-kg-load range with a crosshead speed of 50 mm/min. Tibia ash weights were determined by ashing for 24 h at 615 degrees C. Bone breaking strength in 72 wk of age hens was significantly (P < 0.05) higher in refrigerated tibias (2.48 kg/g) than those in frozen storage (1.75 kg/g). However, there was no difference (P > 0.05) for bone ash (percentage of tibia ash) in all three groups between refrigerated storage (72 wk: 38.840%, 80 wk: 46.40%, 92 wk: 46.99%) and frozen storage (72 wk: 39.12%, 80 wk: 44.88%, 92 wk: 45.35%). This study indicated that frozen storage only influenced assessment of bone strength in 72-wk-old laying hens but could be used for sample storage of bones from older hens.

Aging↗

Poultry digestive microflora biodiversity as indicated by denaturing gradient gel electrophoresis.

Populations of digestive microflora in chickens change with age and are affected by diet, stressors, and performance enhancers. Culturing techniques used to profile a bacterial community inadvertently select for some organisms while excluding others. Several molecular-based techniques have been used to profile mixed microbial populations on the basis of DNA extracted from the entire community. Denaturing gradient gel electrophoresis was used in the present study to examine PCR-amplified fragments (amplicons) of a 16S ribosomal DNA variable region from predominant digestive bacteria. The objective of the study was to examine changes in digestive microbial communities of developing Leghorn chicks and molted Leghorn hens. Dendrograms of amplicon patterns indicated approximately 51% similarity between cecal bacteria composition in Leghorn chicks less than 20 d old and chicks greater than 20 d old. Cecal communities in Leghorn chicks given a competitive exclusion culture exhibited 21% correlation at all ages with those in control chicks. Nonmolted and molted hens had 40% similarity between cecal communities, whereas diets with low calcium (0.8% wt/wt) and excess zinc (2,800 mg/kg) lessened population differences (90% similarity). Results indicated the potential usefulness of the molecular-based denaturing gradient gel electrophoresis to monitor changes in digestive bacterial communities in chickens.

Aging↗

Effect of experimental chlorate product administration in the drinking water on Salmonella typhimurium contamination of broilers.

The crop is a known source of Salmonella and Campylobacter contamination. Previously, we evaluated lactic acid in the drinking water during a simulated pretransport feed withdrawal (FW) and reported 0.44% lactic acid significantly (P < 0.05) reduced the number of Salmonella recovered in market-age broiler crops. However, total consumption of the organic acid-treated drinking water was reduced. Presently, we evaluated the effect of experimental chlorate product (ECP; 1x ECP is equivalent to a 15 mM chlorate ion concentration) during a 10-h pretransport FW. Market-age broilers were obtained from a commercial processing plant and randomly assigned to ECP-treated or control (nontreated) groups. Broilers were challenged by crop gavage with 10(8) Salmonella Typhimurium (ST) immediately upon arrival and 1 d prior to termination of the experiment. One day later, broilers were killed for ST enumeration (cfu) in the crop and ceca. Broilers provided ECP 24 h prior to slaughter consumed slightly more ECP water than broilers provided distilled water. Treatment with ECP caused a significant decrease (P < 0.05) in the incidence of ST in crop contents (2%) as compared to the controls (36.7%). Similarly, ECP treatment caused a significant decrease (P < 0.05) in number of ST (0.96 log10 ST/g cecal content) detected in the ceca when compared to controls (2.52 log10 ST). This study suggested that incorporation of ECP in the drinking water 24 to 48 h prior to slaughter could reduce Salmonella contamination in broilers.

Animals↗

Sodium chlorate supplementation reduces E. coli O157:H7 populations in cattle.

Cattle are a natural reservoir of the food-borne pathogen Escherichia coli O157:H7. Therefore, strategies that reduce E. coli O157:H7 prior to slaughter will reduce human exposures to this virulent pathogen. When bacteria that can anaerobically respire on nitrate (e.g., E. coli) are exposed to chlorate, they die because the intracellular enzyme nitrate reductase converts nitrate to nitrite, but also co-metabolically reduces chlorate to cytotoxic chlorite. Because chlorate is bactericidal only against nitrate reductase-positive bacteria, it has been suggested that chlorate supplementation be used as a strategy to reduce E. coli O157:H7 populations in cattle prior to harvest. Cattle (n = 8) were fed a feedlot-style high-grain diet experimentally infected with three strains of E. coli O157:H7. Cattle were given access to drinking water supplemented with 2.5 mM KNO3 and 100 mM NaCl (controls; n = 4) or 2.5 mM KNO3 and 100 mM NaClO3 (chlorate-treated; n = 4). Sodium chlorate treatment for 24 h reduced the population of all E. coli O157:H7 strains approximately two logs (10(4) to 10(2)) in the rumen and three logs (10(6) to 10(3)) in the feces. Chlorate treatment reduced total coliforms and generic E. coli from 106 to 10(4) in the rumen and by two logs throughout the rest of the gastrointestinal tract (ileum, cecum, colon, and rectum). Chlorate treatment reduced E. coli O157:H7 counts throughout the intestinal tract but did not alter total culturable anaerobic bacterial counts or the ruminal fermentation pattern. Therefore, it appears that chlorate supplementation is a viable potential strategy to reduce E. coli O157:H7 populations in cattle prior to harvest.

Animals↗

Escherichia coli O157:H7 becomes resistant to sodium chlorate in pure culture, but not in mixed culture or in vivo.

AIMS: Chlorate kills Escherichia coli O157:H7 and may be an effective feed additive for use in food animals. This study was designed to determine if development of chlorate-resistant E. coli O157:H7 strains was likely. METHODS AND RESULTS: Escherichia coli O157:H7 was chlorate-sensitive, but became chlorate-resistant in pure batch culture and in sterilized faecal fluid; it was killed in mixed culture and did not become resistant. Addition of chlorate to continuous pure cultures caused chlorate resistance, but chlorate addition to mixed continuous culture eliminated E. coli O157:H7 and no resistance occurred. Piglets challenged with E. coli O157:H7 were treated with chlorate; populations were reduced and colonies were always chlorate-sensitive. CONCLUSION: Chlorate-resistant E. coli O157:H7 can be selected in pure, but not mixed culture, and results suggest that terminal chlorate feeding will not select for chlorate-resistance in vivo. SIGNIFICANCE AND IMPACT OF THE STUDY: Chlorate can reduce food-borne pathogens prior to harvest, but development of resistance does not appear likely in vivo.

Animals↗

Effect of lactic acid administration in the drinking water during preslaughter feed withdrawal on Salmonella and Campylobacter contamination of broilers.

The crop is a known source of Salmonella and Campylobacter contamination. We evaluated the use of selected organic acids (0.5% acetic, lactic, or formic) in drinking water during a simulated 8-h pretransport feed withdrawal (FW). Salmonella typhimurium was recovered from 53/100 control crops and from 45/100 of crops from acetic acid-treated broilers. However, treatment with lactic acid (31/100) or formic acid (28/76) caused significant (P < 0.05) reduction in incidence. Reductions of recovered incidence were also associated with reduced numbers of S. typhimurium recovered (e.g., control, log 1.45 cfu/crop; lactic acid, 0.79 cfu/crop). In an additional commercial farm study, broilers were provided 0.44% lactic acid during a 10-h FW (4 h on the farm and 6 h transport) and pre-FW crop, post-FW crop, and pre-chill carcass wash samples were collected for Campylobacter and Salmonella detection. Crop contamination with Salmonella was significantly reduced by lactic acid treatment (6/175) as compared with controls (29/175). Importantly, Salmonella isolation incidence in prechill carcass rinses was significantly reduced by 52.4% with the use of lactic acid (26/175 vs. 55/176). Crop contamination with Campylobacter was significantly reduced by lactic acid treatment (62.3%) as compared with the controls (85.1%). Lactic acid also reduced the incidence of Campylobacter found on pre-chill carcass rinses by 14.7% compared with the controls. These studies suggest that incorporation of lactic acid in the drinking water during pretransport FW may reduce Salmonella and Campylobacter contamination of crops and broiler carcasses at processing.

Animals↗

Cecal volatile fatty acids and broiler chick susceptibility to Salmonella typhimurium colonization as affected by aflatoxins and T-2 toxin.

Four experiments were conducted using day-of-hatch, mixed-sex broiler chicks to evaluate the effects of aflatoxins and T-2 toxin on cecal volatile fatty acids (VFA) and the susceptibility to Salmonella colonization. All chicks in these experiments were challenged orally with 10(4) cfu of Salmonella typhimurium (ST) on Day 3. In Experiments 1 and 2, chicks were fed diets containing 0, 2.5, or 7.5 mg aflatoxins/kg of diet and were allowed to develop their microflora naturally. In Experiment 3, all chicks were orally gavaged on the day of hatch with a competitive exclusion (CE) culture (PREEMPT) and were fed diets containing 0, 2.5, or 7.5 mg T-2 toxin/kg. In Experiment 4, the chicks were fed diets containing 0, 7.5, or 15.0 mg T-2 toxin/kg and one-half of the chicks were orally gavaged on the day of hatch with the CE culture. In Experiments 1 and 2, with the exception of increased total VFA at 5 d in chicks fed the 7.5 mg T-2 aflatoxins/kg diet, there were no treatment effects on cecal propionic acid, total VFA, or incidence or severity of ST colonization. In Experiment 3, the only alteration in concentration of cecal propionic acid or total VFA was a significant reduction in total VFA at 5 d in chicks fed the 2.5 mg T-2 toxin/kg diet. No significant treatment differences were observed for numbers of Salmonella cecal culture-positive chicks or for numbers of ST in the cecal contents. In Experiment 4, with minor exceptions, the chicks treated with the CE culture had higher cecal concentrations of propionic acid and were less susceptible to Salmonella colonization than the non-CE-treated chicks. In the non-CE-treated chicks, T-2 toxin had no effect on any of the parameters, and 85 to 90% of the chicks were Salmonella cecal culture-positive. In the CE-treated chicks, there was a decrease in propionic acid concentration at 3 and 11 d and an increase in susceptibility to Salmonella colonization of the chicks fed the 15.0 mg T-2 toxin/kg diet. These results indicate that cecal concentrations of VFA can be affected by toxins, such as high concentrations of T-2 toxin, and that resistance to Salmonella colonization may be reduced. Further research is necessary to determine the biological significance of these changes.

Aflatoxins↗

Effects of tannic acid on cecal volatile fatty acids and susceptibility to Salmonella typhimurium colonization in broiler chicks.

Young chickens are more susceptible to Salmonella colonization than older chickens that have developed resistance with age as native microflora become established. Elevated concentrations of cecal propionic acid and total volatile fatty acids (VFA) have been observed by many researchers to be indicators of establishment of anaerobic microflora and protection against Salmonella colonization of the ceca. Disruption of the native microflora or competitive exclusion (CE) cultures by components of diets, such as tannic acid (TA), could alter the concentrations of propionic acid and total VFA and possibly affect Salmonella colonization. Two experiments were conducted using day-of-hatch, mixed-sex broiler chicks to evaluate the effects of TA on cecal VFA and the susceptibility to Salmonella colonization. All chicks in both experiments were challenged orally with 10(4) cfu of Salmonella typhimurium (ST) on Day 3 (Experiment 1) or Day 4 (Experiment 2). One-half of the chicks were orally gavaged on the day of hatch with a CE culture (PREEMPT) and were fed diets containing 0, 0.75, or 1.5% TA for up to 12 d of age. Chicks were maintained in batteries in separate rooms for the experimental period. There were some alterations in concentrations of cecal propionic acid or total VFA in chicks fed diets containing 0.75 or 1.5% TA in non CE-treated chicks and in CE-treated chicks. No significant differences were observed for numbers of Salmonella cecal culture-positive chicks or in the numbers of ST in the cecal contents due to dietary content of TA. With minor exceptions, the chicks treated with the CE culture had higher cecal concentrations of propionic acid and were less susceptible to Salmonella colonization than the non CE-treated chicks. Further research is necessary to determine the biological significance of these changes.

Animals↗

Toxicity of moniliformin from Fusarium fujikuroi culture material to growing barrows.

In two studies, the effects of moniliformin (M)-contaminated diets from Fusarium fujikuroi culture material on growing barrows were evaluated. In the first study, six barrows (three replicates of two each, mean body weight = 17.8 kg) per group (four groups; 24 barrows total) were fed diets calculated to contain 0 mg M/kg feed (control); 25 mg M/kg feed; 50 mg M/kg feed; or 100 mg M/kg feed for 28 days. In the second study, the same experimental design and numbers of barrows (mean body weight = 15.3 kg) were used, and diets were formulated to contain 0 mg M/kg feed (control); 50 mg M/kg feed; 100 mg M/kg feed; or 200 mg M/kg feed. Diets of 100 mg or 200 mg M/kg feed reduced body weight, body weight gain, and feed consumption. Serum biochemical analytes were affected by 100 to 200 mg M/kg feed. Hematologic values were affected by 50, 100, and 200 mg M/kg feed. In the first study, one barrow in the 100 mg M-treated group died, and in the second study. one barrow died in the 100 mg M-treated group, and five barrows died in the 200 mg M-treated group. Relative heart weight was increased in the 200 mg M-treated barrows, yet tissues from organs collected from treatment groups were generally histologically unimpressive. The most consistent sign of M toxicity in barrows appeared to be death induced within 2 to 5 days by 100 to 200 mg M/kg feed.

Animal Feed↗

Effect of sodium chlorate on Salmonella typhimurium concentrations in the weaned pig gut.

Salmonella cause economic losses to the swine industry due to disease and compromised food safety. Since the gut is a major reservoir for Salmonella, strategies are sought to reduce their concentration in pigs immediately before processing. Respiratory nitrate reductase activity possessed by Salmonella also catalyzes the intracellular reduction of chlorate (an analog of nitrate) to chlorite, which is lethal to the microbe. Since most gastrointestinal anaerobes lack respiratory nitrate reductase, we conducted a study to determine if chlorate may selectively kill Salmonella within the pig gut. Weaned pigs orally infected with 8 x 10(7) CFU of a novobiocin- and nalidixic acid-resistant strain of Salmonella Typhimurium were treated 8 and 16 h later via oral gavage (10 ml) with 0 or 100 mM sodium chlorate. Pigs were euthanized at 8-h intervals after receiving the last treatment. Samples collected by necropsy were cultured qualitatively and quantitatively for Salmonella and for most probable numbers of total culturable anaerobes. A significant (P < 0.05) chlorate treatment effect was observed on cecal concentrations of Salmonella, with the largest reductions occurring 16 h after receiving the last chlorate treatment. An observed treatment by time after treatment interaction suggests the chlorate effect was concentration dependent. Chlorate treatment may provide a means to reduce foodborne pathogens immediately before harvest.

Animals↗

Cottonseed with a high (+)- to (-)-gossypol enantiomer ratio favorable to broiler production.

This study was designed to evaluate the relative toxicity of (+)- and (-)-gossypol enantiomers in 0-3-week-old broilers. Treatments consisted of broiler starter diets formulated with either a glandless, which did not contain gossypol, a commercial glanded [62. 2% (+)-gossypol], or a glanded moco [83.2% (+)-gossypol] crushed cottonseed (CCS) (six replicates/treatment) plus a soybean meal negative control. Glandless cottonseed was mixed with the moco cottonseed (2.4% free gossypol) so that both the commercial glanded and moco glanded cottonseeds contained equivalent concentrations of free gossypol (2.0%). The cottonseed treatments were added at 5 and 10% of the diet. Body weights and feed conversions were determined weekly. Body weights and feed-to-gain ratios of broilers fed 5 and 10% glandless CCS and 5% moco CCS were not significantly different. Broilers receiving 10% commercial glanded CCS weighed significantly less than those subjected to all other treatments. Feed-to-gain ratios were significantly higher for broilers receiving 10% commercial glanded and 10% moco CCS as compared to 5% moco and glandless CCS, 10% glandless CCS, and control. Relative liver weights of birds receiving 10% moco CCS were significantly less than those of birds receiving 10% commercial CCS. The data clearly showed that broilers fed moco CCS containing a relatively high (+)- to (-)-gossypol enantiomer ratio performed better than broilers receiving commercial CCS with a lower (+)- to (-)-gossypol enantiomer ratio.

Animal Feed↗

Bactericidal effect of sodium chlorate on Escherichia coli O157:H7 and Salmonella typhimurium DT104 in rumen contents in vitro.

Escherichia coli O157:H7 and Salmonella Typhimurium DT104 are important foodborne pathogens affecting the beef and dairy industries and strategies are sought to rid these organisms from cattle at slaughter. Both pathogens possess respiratory nitrate reductase that also reduces chlorate to the lethal chlorite ion. Because most anaerobes lack respiratory nitrate reductase, we hypothesized that chlorate may selectively kill E. coli O157:H7 and Salmonella Typhimurium DT104 but not potentially beneficial anaerobes. In support of this hypothesis, we found that concentrations of E. coli O157:H7 and Salmonella Typhimurium DT104 were reduced from approximately 1,000,000 colony forming units (CFU) to below our level of detection (< or = 10 CFU) following in vitro incubation (24 h) in buffered ruminal contents (pH 6.8) containing 5 mM added chlorate. In contrast, chlorate had little effect on the most probable number (mean +/- SD) of total culturable anaerobes (ranging from 9.9 +/- 0.72 to 10.7 +/- 0.01 log10 cells/ml). Thus, chlorate was bactericidal to E. coli O157:H7 and Salmonella Typhimurium DT104 but not to potentially beneficial bacteria. The bactericidal effect of chlorate was concentration dependent (less at 1.25 mM) and markedly affected by pH (more bactericidal at pH 6.8 than pH 5.6).

Animals↗

Utilization of electrochemically generated ozone in the degradation and detoxication of benzo[a]pyrene.

The ability of electrochemically generated ozone (O3) to degrade and detoxify the polycyclic aromatic hydrocarbon (PAH) benzo[a]pyrene (BaP) was assessed utilizing the chick embryotoxicity screening test (CHEST) and Hydra attenuata bioassays. Aqueous solutions containing 10 microg/ml BaP and 0.5% (v/v) acetonitrile were subjected to ozonolysis for 0 to 30 min. Rapid degradation of BaP was evident by both gas chromatography/mass spectroscopy (GC/MS) and high-performance liquid chromatography (HPLC) analysis. HPLC fluorescence detection revealed no BaP shortly after 5 min of ozonolysis, while HPLC with PDA detection demonstrated continued reactions with ozone over the 30-min time course. As little as 2 min of O3 treatment afforded protection from BaP-induced mortality and toxicity (embryolethality and liver discoloration) in the chicken embryos. In the hydra bioassay, no toxicity was observed in the adult hydra until the ozonolysis products were reconstituted 100-fold from their initial post-ozonolysis concentrations. The results obtained from this study clearly demonstrate the potential application of electrochemically generated O3 for the detoxication and prevention of toxicity of BaP. Both CHEST and hydra assays predict that the ozonolysis products of BaP are less toxic than the parent compound.

Acetonitriles↗

Assessment of the estrogenic effects of zearalenone after treatment with ozone utilizing the mouse uterine weight bioassay.

The ability of ozone gas (O3) to detoxify zearalenone (ZEN), a commonly occurring estrogenic mycotoxin, was assessed utilizing the mouse uterine weight bioassay. Solutions containing 12 ppm ZEN in water were ozonated for varying time periods (0, 0.5, and 5 min), then extracted with chloroform and evaporated to dryness. The residue was redissolved in acetonitrile and analyzed for ZEN. High-performance liquid chromatography (HPLC) analysis of aliquots indicated a rapid degradation and decline in parent ZEN level with increasing time of ozone treatment. The acetonitrile solution containing the degraded ZEN residue was added to a known volume of corn oil and evaporated under nitrogen to eliminate the acetonitrile in the oil. Eighteen-day-old prepubertal female mice (B6C3F1 strain) were gavaged daily with the test chemicals in 50 microl of corn oil between d 18 and 23. Initial dose-response studies showed that a concentration of 60 microg ZEN/mouse/d produced uterine weights that were significantly higher than the uterine weights of control animals (2.7 times higher than that of the solvent control). Treatment groups for the ozonation study included: DES, 0.1 microg (positive control), untreated ZEN (60 microg), extraction control for ZEN (60 microg), 0.5 min ozone-treated ZEN (60 microg), 5 min ozone-treated ZEN (60 microg), solvent control (50 microl), and absolute control. Results showed the uterine weights of animals receiving the ozone-treated ZEN were not significantly affected. These findings were in agreement with HPLC analyses and suggested that ozone can prevent the estrogenic effects of this important mycotoxin in mice. Importantly, ozone treatment of contaminated whole grains may enable the practical detoxification and control of ZEN. Also, the mouse uterine weight bioassay may be useful in assessing the efficacy of other detoxification strategies for estrogenic chemicals.

Animals↗

Multi-bioassay approach for assessing the potency of complex mixtures of polycyclic aromatic hydrocarbons.

The chick embryotoxicity screening test (CHEST) and the Salmonella/microsome bioassay were used to evaluate embryotoxic and mutagenic endpoints from crude coal tar (CT) and its fractionated polycyclic aromatic hydrocarbon (PAH) mixtures (designated as A, B, C, D and E). In the CHEST assay, CT and PAH mixtures were injected into the egg yolk. A dose-dependent increase in embryo mortality was observed for all fractions. The E fraction resulted in 47% embryo mortality at a dose of 0.125 mg/kg and was more toxic than CT. At a dose of 1 mg/kg, 85-100% embryonic deaths occurred in fractions C and D and these two fractions were more potent than fractions A and B. The main visual toxic manifestations were liver lesions, discoloration of the liver, and edema. Both CT and fractionated PAH mixtures were also tested in the Salmonella/microsome plate incorporation assay with Salmonella typhimurium strain TA98 and were evaluated with and without metabolic activation at five dose levels. In the presence of S9, the CT and fractions C, D and E induced a dose-dependent positive response. Results from the Salmonella/microsome assay were in good agreement with findings from the CHEST assay suggesting that these two bioassays in combination may facilitate the rapid detection and ranking of complex PAH mixtures.

Animals↗

Toxicological evaluations of cyclopiazonic acid and ochratoxin A in broilers.

The individual and combined effects of ochratoxin A (OA) and cyclopiazonic acid (CPA) were evaluated in Petersen x Hubbard broiler chickens from 1 d to 3 wk of age. The experimental design was a 2 x 2 factorial with treatments of 0 and 2.5 mg OA/kg feed and 0 and 34 mg CPA/kg feed. Production performance, serum biochemistry, and gross pathological observations were evaluated. Body weight gain was reduced (P < 0.05) by OA, CPA, and OA-CPA in combination at the end of 3 wk. Ochratoxin A significantly increased the relative weight of the kidney and serum concentrations of uric acid and triglycerides and decreased total protein, albumin, and cholesterol. The toxicity of CPA was expressed primarily through increased relative weights of the proventriculus and increased activity of creatine kinase. Exposure to OA-CPA was characterized by increased relative weights of the liver, kidney, pancreas, and proventriculus; decreased concentrations of serum albumin, total protein, and cholesterol; increased activity of creatine kinase; and increased concentrations of triglycerides and uric acid. Postmortem examination revealed that the chickens fed CPA or OA-CPA had thickened mucosa and dilated proventricular lumen. Data from this study demonstrate that OA, CPA, and the OA-CPA combination can limit broiler performance and adversely affect broiler health. The interaction of the compounds was primarily additive or less than additive in the parameter in which the interaction occurred.

Animal Feed↗

Effects of long-term feeding of diets containing moniliformin, supplied by Fusarium fujikuroi culture material, and fumonisin, supplied by Fusarium moniliforme culture material, to laying hens.

Beginning at 24 wk of age, control diets or diets containing 50 or 100 mg/kg moniliformin (M), 100 or 200 mg/kg fumonisin B1 (FB1), or a combination of 50 mg M and 100 mg FB1/kg of diet were fed to White Leghorn laying hens for 420 d. The hens were then fed the control diet for an additional 60 d. At the beginning of the experiment, each treatment consisted of four replicates of six hens. Egg production was reduced by approximately 50% by the end of the second 28-d laying period and remained at approximately this level for the 420 d in only the hens fed the diet containing 100 mg M/kg feed. Production returned to control levels or above within 60 d after hens were fed the control diet. Egg weights were reduced by the 100-mg M diet during the first three 28-d laying periods before returning to weights comparable with controls. The hens in this group also had significantly lower body weights than the other treatments. Mortality was minimal except in hens fed the 100 mg M/kg diet and the 100 mg FB1/kg diet, on which approximately 20% of the hens died. The hens were artificially inseminated with semen from males fed control diets, and fertility was not affected by the dietary treatments. Importantly, toxic synergy between M and FB1 was not observed for any of the parameters measured. Results indicate that laying hens may be able to tolerate relatively high concentrations of M and FB1 for long periods of time without adversely affecting health and performance. Interestingly, hens fed the 100-mg M/kg diet were able to recover when returned to control diets. The likelihood of encountering M or FB1 at these concentrations in finished feed is small.

Animal Feed↗