Influence of vitamin E on aflatoxicosis in growing swine

Effects of dietary aflatoxin (AF) and supplemental vitamin E (d-alpha-tocopherol) were evaluated in growing crossbred pigs. Nine barrows (3 replicates of 3 each, mean body weight, 14.0 kg) per group were assigned to 1 of 4 treatment groups (for a total of 36 barrows): 0 IU of supplemental vitamin E and 0 mg of AF/kg of feed (control); 2,400 IU of vitamin E divided into equal doses and administered IM on days 1 and 16; 2.5 mg of AF/kg of feed; or 2.5 mg of AF/kg of feed plus 2,400 IU of vitamin E administered similarly to treatment 2. Barrows were administered their respective treatment for 32 days. Evaluations were made for group production performance and for serum biochemical, immunologic, hematologic, pathologic, serum and tissue tocopherol, and serum retinol variables. Body weight was reduced by AF-alone and AF plus vitamin E treatments, compared with control and vitamin E-alone treatments. Liver weight was increased for the AF alone-treated and the AF plus vitamin E-treated barrows, compared with control barrows. The AF alone-treated barrows had alterations in:serum values of alkaline phosphatase, gamma-glutamyltransferase, albumin, glucose, phosphorus, calcium, cholesterol, total iron, unsaturated iron-binding capacity, total iron-binding capacity, and urea nitrogen; RBC numbers, hematocrit, hemoglobin concentration, and prothrombin time; and mitogen-induced lymphoblastogenic responses. With the exception of some slight ameliorating effects on hematologic measurements, supplemental treatment with vitamin E did not prove beneficial against the toxicosis-associated AF treatment. The AF alone-treated barrows had decreased serum tocopherol and retinol concentrations, compared with control and pretest values, and decreased tocopherol concentration in cardiac tissue. High parenterally administered doses of vitamin E did not have sparing effect on AF-induced reductions of serum tocopherol or retinol concentration; however, compared with pretest values, serum tocopherol concentration was increased by vitamin E-alone treatment. Tocopherol concentration in cardiac tissue of the AF plus vitamin E-treated barrows was increased over that of the AF alone-treated barrows, indicating an ameliorating effect on AF-induced tissue concentrations reductions. These data indicate that vitamin E may not have a sparing effect on AF-induced toxicosis and that AF may reduce serum retinol and serum and tissue tocopherol concentrations.

Temporal and dose-response features in swine fed corn screenings contaminated with fumonisin mycotoxins

Fumonisin B1 (FB1), a mycotoxin produced by Fusarium moniliforme and F. proliferatum, induces liver damage and pulmonary edema in swine. We examined the temporal and dose-response features of FB1 toxicosis in male weanling crossbred pigs fed nutritionally balanced diets, containing corn screenings naturally contaminated with fumonisins, for 14 days. Total fumonisins (FB1 and FB2) in diets 1 through 6 were assayed at 175, 101, 39, 23, 5, and < 1 ppm (below detectable concentrations), respectively. Clinical signs, serum biochemical alterations, and morphologic changes were evaluated. Pigs were weighed, and bled for hematologic and clinical chemistry evaluation on days 5 and 14. They were euthanized on day 14, or earlier if respiratory distress was observed. Respiratory distress developed in 3/5 pigs fed diet 1 between days 4 and 6 due to severe pulmonary edema and pleural effusion. Histologic evidence of hepatic injury was present in all pigs fed diets 1 and 2, 3/5 on diet 3, and 1/5 on diet 4. Serum bilirubin and cholesterol concentrations, gamma-glutamyl transferase (GGT), alkaline phosphatase (ALP), alanine aminotransferase (ALT), aspartate aminotransferase (AST), and arginase (ARG) activities were elevated in pigs fed diets 1 and 2. Based on liver histopathology, the no observed adverse effect level (NOAEL) for fumonisin toxicity in swine was < 23 ppm total fumosins for the 14-day period. Based on regression analyses of the clinical chemistry profiles at 14 days, the NOAEL was < 12 ppm, with ALP being the most sensitive parameter. In conclusion, pulmonary edema occurred only at the highest fumonisin concentration (175 ppm), while liver damage occurred at much lower concentrations with a NOAEL of < 12 ppm.

The use of Saccharomyces cerevisiae to suppress the effects of aflatoxicosis in broiler chicks

Three hundred and sixty day-old commercial broiler chicks were assigned to a 3 x 2 factorial arrangement of treatments to examine the effects of three levels of Saccharomyces cerevisiae 0, .05, and .1% of feed, and two levels of aflatoxin, 0 and 5 ppm, singly and in combination on aflatoxicosis. Each treatment group was replicated three times. The S. cerevisiae and aflatoxin were incorporated in a standard commercial broiler ration and fed to chicks for 4 wk. Data were collected weekly on body weights, and at the end of the experiment on the relative weights of the liver, proventriculus, pancreas, and heart. Serum concentrations of the albumin, total protein, cholesterol, uric acid, triglycerides, and enzyme activities of alanine transaminase, aspartate aminotransferase, lactase dehydrogenase, and creatine phosphokinase were also evaluated. Results showed that chicks receiving aflatoxin-contaminated feed had suppressed body weight (456 g), which significantly improved (516 g) with the inclusion of .1% S. cerevisiae. The relative weights of liver (3.58%), heart (.916%), and proventriculus (.770%), which increased significantly with the addition of 5 ppm of aflatoxin, were restored to 3.00, .783, and .680%, respectively, with the dietary inclusion of .1% S. cerevisiae. The serum concentrations of albumin and total protein (.66 and 1.62 g/100 mL), which were significantly decreased by aflatoxin, were elevated to .88 and 2.24 g/100 mL, respectively, with the inclusion of .1% S. cerevisiae.(ABSTRACT TRUNCATED AT 250 WORDS)

Bioassay of mycotoxins using terrestrial and aquatic, animal and plant species

The role of bioassay in the diagnosis of mycotoxicoses in farm animals is discussed. Methods for detecting mycotoxin contamination of animal feeds using biological species (aquatic and terrestrial animals and plants but excluding bacteria and yeast) are reviewed. Factors that need to be considered when choosing and using particular bioassay procedures in a feed-screening programme are discussed in relation to the occurrence of false positives and false negatives.

[The species composition of the micromycetes in feed and their role in animal kojic acid toxicosis]

Microflora of more than 100 samples of different sorts of foodstuff (coarse fodder, grain forage, mixed fodder, premixes, silo, whole milk substitute etc.) selected in 1989-1992 in the period of mass diseases and death of animals in farms of Ukraine has been studied. It is shown that the amount of spore material included in lg of fodder, depends on the sort of feed substrate. Grains and grain forage (94.5 thou. spores in 1 g) occupy the first place in sporification with fungi; vetch-oat mixture and whole milk substitute (82-89 thou. spores)--the second place; mixed fodder granules and maize briquettes (79.5-66.5 thou. spores)--the third place; the latter are mixed fodder plants hay, cereals straw (11.8-43.5 thou. spores). Aspergillus mainly occurred on the concentrated forage, grain, grain forage, in less amount--in grass stand, cereals straw. Penicilli, fusari and other species of saprophytic fungi dominated on hay of natural meadows, on mixed fodder plants and cereals straw. It has been stated that the highest toxicity was typical of the fodder samples infected with Aspergillus strains producing kojic acid. Under conditions of our experiments out of 67 strains of genus Aspergillus kojic acid was synthesized by 48.6% of the total number of the tested fungus cultures. The greatest number of kojic acid producers was found among Aspergillus flavus isolates (56.8%) the less number--among A. fumigatus (36.7%). Kojic acid has been revealed to exert a pathological effect on the organism of different animal species.

The natural occurrence of aflatoxin B1 in Moroccan poultry feeds

The occurrence of AFB1 in Moroccan poultry feeds and their ingredients was evaluated. Thirty poultry farms and 4 feedmills were surveyed from September 1989 to June 1991, and 300-500 g each of feeds (corn, sorghum, wheat bran, soybean meal, cottonseed meal, sunflower meal, finished feeds) were sampled. Additionally, on farms with suspected mycotoxin problems, necropsies of affected chickens were performed for gross and microscopic examinations. A total of 315 samples were analysed for AFB1 using a semi-quantitative enzyme linked immuno-sorbent assay (ELISA kits) and thin-layer chromatography. In feedmills, 4% of samples contained AFB1; 17% among sunflower meal samples (20-80 ppb) and 4% among corn (110 ppb) and mixed feed samples (20-110 ppb). On poultry farms, 17% of samples were found contaminated with AFB1; 20% were positive among pellets and 16% among crumbles and 15% mash feeds. The level of contamination ranged from 20 ppb to 200 ppb, except for 4 samples that contained high levels of AFB1 (2000-5625 ppb). These highly-contaminated samples were associated with clinical aflatoxicosis in broiler chickens. The most frequent incidence of AFB1 contamination and the highest AFB1 contamination occurred in feeding troughs (23%). Aflatoxins should be considered potential contaminants of poultry feeds under Moroccan conditions.

Ryegrass staggers in heifers: a new mycotoxicosis in Argentina

Aberdeen Angus (AA) and crossbred AA x Hereford 8-9 mo old heifers (560 animals) showed a typical perennial ryegrass (PRG) staggers syndrome after grazing 26 d in a 25-hectare paddock of pure Lolium perenne. Effects were observed in about 50% of the herd. When forced to move, the animals showed incoordination, weakening of the forelimbs, falling on the chest and neck, and moving in this position during the first steps before recovering a normal gait. In severely affected animals all of the 4 limbs had extreme rigidity. All the affected animals had generalized tremors. Twelve days after removal from this pasture the animals had no symptoms. The symptoms described, the pasture conditions (mostly PRG stubble and short PRG green plants in slow growth), a positive mouse bioassay of extracts obtained from the basal part of the PRG plants, and the microscopic finding of Acremonium lolii hyphae in the leaf sheaths of the same plant material produced diagnostic evidence to confirm this as a PRG staggers case, the first reported in Argentina.

Major biological consequences of aflatoxicosis in animal production

Aflatoxins, a family of closely related, biologically active mycotoxins, have been known as a prominent cause of animal disease for 30 yr. The toxins occur naturally on several key animal feeds, including corn, cottonseed, and peanuts. Occurrence of aflatoxin on some field crops tends to spike in years when drought and insect damage facilitate invasion by the causative organisms, Aspergillus flavus and A. parasiticus, which abound in the crop's environment. Acute aflatoxicosis causes a distinct overt clinical disease marked by hepatitis, icterus, hemorrhage, and death. More chronic aflatoxin poisoning produces very protean signs that may not be clinically obvious; reduced rate of gain in young animals is a sensitive clinical register of chronic aflatoxicosis. The immune system is also sensitive to aflatoxin, and suppression of cell-mediated immune responsiveness, reduced phagocytosis, and depressed complement and interferon production are produced. Acquired immunity from vaccination programs may be substantially suppressed in some disease models. In such cases the signs of disease observed are those of the infectious process rather than those of the aflatoxin that predisposed the animal to infection. Mixtures of aflatoxin with other mycotoxins can result in greatly augmented biological responses in terms of rate of gain, lethality, and immune reactivity. Because of its great biological activity, its wide-spread potential presence in areas where critical feed crops are grown, and its propensity to spike in problem years, aflatoxin promises to be a continuing problem in animal production.

Effects of feeding diets containing endophyte-infected fescue seed on luteinizing hormone secretion in postpartum beef cows and in cyclic heifers and cows

Two experiments were conducted to investigate the effect of feeding endophyte (Acremonium coenophialum)-infected fescue (Festuca arundinacea Shreb.) seed on LH secretion in postpartum beef cows and in cycling heifers and cows. In Exp. 1, spring-calving primiparous Angus cows (n = 16) were pair-fed for 75 d diets that contained endophyte-free or endophyte-infected (95%) fescue seed that contained 1.3 micrograms/g of ergovaline and 5.2 mg/g of saturated pyrrolizidines. Serial blood samples for basal and GnRH-stimulated serum LH analysis were obtained on d 7, 28, 42, and 56 of the study. The endophyte had no effect on LH secretion (basal, pulse frequency, and amplitude) or milk production. Average daily gain was decreased (P < .05) in cows that consumed infected fescue seed compared with controls (-.20 vs -.01 kg, respectively). Basal serum prolactin concentrations were reduced (P < .01) in treated compared with control cows (8.9 vs 25.4 ng/mL, respectively) on d 70. In Exp. 2, cycling Angus heifers (n = 8; age = 2 yr) and cows (n = 8; age = 4 yr) stratified by age were pair-fed for 40 d diets that contained the noninfected or the highly infected fescue seed. Estrus was synchronized by prostaglandin F2 alpha (d 18 and 28). Serial blood samples for serum LH analysis were obtained on d 28 (luteal phase) and d 30 (follicular phase). The endophyte did not affect LH (P > .28) or prolactin (P > .16) secretion, whereas ADG was decreased (P < .05) in treated compared with control animals (.32 vs .70 kg/d, respectively).

Investigations in the use of mice exposed to mycotoxins as a model for growing pigs

A series of experiments was conducted to determine the feasibility of using mice to screen for possible dietary mycotoxin interactions before testing them with swine. Selected mycotoxins, deoxynivalenol (DON) and T-2 toxin, were fed to young mice, alone and in combination. The severity of effects on body weights caused by DON (0-20 mg DON/kg diet) was more pronounced in a dose-related manner when the animals were exposed to contaminated diets starting at 21 d of age than at 28 d (Experiment 1) as reflected in the analysis of variance. The relative variance among diets after 7 d was twice as great for the younger than for the older mice. In both age groups, the weight gain response was linear, similar to that seen in growing swine. In Experiment 2, a significant (p < .05) diet type x DON interaction for food consumption evident after 7 d, indicated that the effect of DON depended on the type of diet (freeze-dried vs. regular mash). There was no difference in food efficiency between diet type, but a strong dose-dependent effect due to DON was observed. When DON and T-2 toxin were fed together to young mice, a significant (p < .001) linear decrease in weight gain and food consumption was observed after 7 d on the contaminated diet as the toxin concentration increased.

Mycotoxins and reproduction in domestic livestock

Molds are parasitic plants that are ubiquitous in livestock feedstuffs. Even though molds themselves reduce the quality of grains, their synthesis of chemical substances termed mycotoxins causes the greatest monetary loss to the animal industry. Five major mycotoxins that impair growth and reproductive efficiency in North America are aflatoxins, zearalenone, deoxynivalenol, ochratoxin, and ergot. Aflatoxins are produced by Aspergillus flavus and Aspergillus parasiticus. Consumption of grains containing aflatoxins by swine affects reproduction indirectly by reducing feed intake and growth. In swine, aflatoxins impair liver and kidney function, delay blood clotting, increase susceptibility to bruising, and interfere with cellular humoral immune systems. Ruminants are comparatively resistant to aflatoxicosis, but presence of aflatoxins in milk of dairy cows is closely monitored for human safety. Depending on environmental conditions, Fusarium roseum can produce either zearalenone or deoxynivalenol. Days 7 to 10 postmating seem to be a critical period of gestation for zearalenone to exert its detrimental actions on early embryonic development. Presence of deoxynivalenol in swine feedstuffs decreases feed intake, causes feed refusal, and induces occasional vomiting. Several species of Penicillium and Aspergillus produce ochratoxin, a mycotoxin that causes necrosis of kidney tissue. Ergot alkaloids produced by Claviceps purpurea on wheat can cause reproductive problems and are associated with lactational failure in swine. Various methods have been developed to remove mycotoxins from infected feedstuffs. Chemical analyses in laboratories as well as diagnostic kits suitable for use at the elevator or farm can be used successfully to identify which mycotoxins are present in suspect feedstuffs.

[Mortality of cattle following feeding of moldy flower bulbs]

Five of eight meat cattle died suddenly without showing prior symptoms of disease. The sudden death occurred in connection with the feeding of mouldy tulip bulbs. A short review is given of the use of flower bulbs as cattle feed, the use of herbicides/fungicides in bulb cultivation, and the relevant legislation. Several toxicological aspects that should be taken into consideration when flower bulbs are used as cattle feed are discussed. Both the Central Veterinary Institute and the State Institute for Public Health and Environmental Hygiene showed, in experiments with mice, the presence of a toxin in extracts of the mouldy tulip bulbs. This toxin is probably produced by moulds present in the tulip bulbs. The death of the animals was probably caused by an as yet unidentified mycotoxin.

Perinatal mortality in lambs of ewes exposed to cultures of Diplodia maydis (= Stenocarpella maydis) during gestation

During 1987 when cob rot was rife, perinatal losses were reported in flocks and herds that had been exposed to diplodiosis. The affected lambs or calves were either stillborn or died soon after birth. Dosing trials at the Onderstepoort Veterinary Research Institute involving 82 ewes revealed that 66% of the offspring of dams exposed to cultures of Diplodia maydis (= Stenocarpella maydis) in the second trimester of pregnancy and 87% of lambs of ewes exposed in the third trimester were born dead or died soon afterwards. A status spongiosus similar to that of the field cases was present in the white matter of the brains of all the affected lambs. The lambs of ewes that had shown nervous signs and those of ewes that had not shown such signs were equally affected. The experiments also clearly demonstrated that foetuses were much more susceptible to diplodiosis than the adults, e.g. in the third trimester 87% of the lambs were affected compared to only 44% of the dams. No perinatal mortalities were recorded in the group exposed to the culture in the first trimester. Ewes developed significant resistance to intoxication after initial exposure to the culture and both the length of gestation and birth mass of the affected lambs were less than those of their untreated counterparts.

High dietary fat increases toxicity of diacetoxyscirpenol in chickens

The influence of high dietary fat on the toxicity of diacetoxyscirpenol (DAS) was investigated in a 2 x 5 factorial arrangement of treatments (6 and 12% fat, and 0, 1, 2, 4, and 8 micrograms DAS/g diet). The 3-wk body weight was decreased (P less than .0001) by DAS, but fat had no significant (P less than .05) effect. There was a highly significant (P less than .0059) interaction manifested at the higher levels of DAS by a greater decrease in body weight in the high-fat diet than in the low-fat diet. Neither feed conversion nor percentage of fat in fecal material were affected significantly (P less than .05) by DAS. These data were consistent with the high-fat diet promoting lipid micellar absorption of DAS and with DAS, once absorbed, inhibiting protein synthesis at the ribosomal level, a well established mechanism of action for trichothecene toxins such as DAS.

Mycotoxicosis: mechanisms of immunosuppression

Mycotoxins are structurally diverse secondary metabolites of fungi that grow on feedstuffs consumed by animals and man. The clinical toxicologic syndromes caused by ingestion of fungal toxins have been characterized in domestic animals, poultry and laboratory animals and range from acute mortality to decreased production. Consumption of some mycotoxins, at levels that do not cause overt clinical mycotoxicosis, suppress immune functions and may decrease resistance to infectious disease. The sensitivity of the immune system to mycotoxin-induced immunosuppression arises from the vulnerability of the continually proliferating and differentiating cells that participate in immunemediated activities and regulate the complex communication network between cellular and humoral components. Mycotoxin-induced immunosuppression may be manifested as depressed T or B lymphocyte activity, suppressed immunoglobulin and antibody production, reduced complement or interferon activity, and impaired macrophage-effector cell function. Although the cellular-molecular basis for many of the specific immunosuppressive effects of mycotoxins are presently unclear, inhibition of DNA, RNA and protein synthesis via a variety of different mechanisms appears to be directly or indirectly responsible for the immunosuppressive action of many mycotoxins.

Measurement of malabsorption of carotenoids in chickens with pale-bird syndrome

Because pale-bird syndrome (PBS), defined as the failure of birds to realize the color potential of their diet, has been demonstrated to be caused by malabsorption or by hyperexcretion of carotenoids, a method for measuring malabsorption of carotenoids would be useful. The absorption of dietary canthaxanthin, a red diketocarotenoid, into serum during aflatoxicosis was measured in an experiment with a 2 x 9 factorial arrangement of treatments (0 and 5 micrograms of aflatoxin/g of diet; serum collected at 0, 2, 4, 6, 8, 10, 12, 14, and 24 h after a standard meal fed to four groups of 10 3-wk-old birds). Serum canthaxanthin levels determined by HPLC attained plateau values between 8 and 14 h after the meal. The absorption of canthaxanthin was depressed significantly (P less than .05) in birds with aflatoxicosis from 4 to 24 h after feeding the standard meal. Four field flocks diagnosed as having PBS were tested for malabsorption by intubating 10 birds with a standard amount of canthaxanthin and measuring serum canthaxanthin 12 h later. One flock had about 85% normally pigmented birds and 15% extremely pale birds, the second flock had a coccidiosis history, the third had a Newcastle disease history, and the fourth had a history of both coccidiosis and Newcastle disease. The flocks were 5- to 6-wk-old, received feed of the same manufacture, and their disease outbreaks had occurred 2 wk earlier.(ABSTRACT TRUNCATED AT 250 WORDS)

Mouth lesions in broiler chickens caused by scirpenol mycotoxins

Dietary scirpentriol (STO), triacetoxyscirpenol (TAS), monoacetoxyscirpenol (MAS), and diacetoxyscirpenol (DAS), mycotoxins produced by Fusarium species, were compared for their ability to cause mouth lesions when graded dietary levels (0, 1, 2, 4, and 8 micrograms STO or TAS/g; 0, .5, 1, 2, and 4 micrograms MAS or DAS/g) were fed to male broiler chickens for 21 days after hatching. The mouth lesions provoked by each scirpenol were dose-related. The minimum effective doses (MED) were 4, 2, 1, and .5 micrograms/g for TAS, STO, DAS, and MAS, respectively, whether the number of affected birds or the number of affected mouth parts (angles, upper beak, lower beak, and tongue) was the measured response. Lesion sites in the mouth varied with the toxin. The rank orders from greatest to least affected sites were angles, upper beak, lower beak, and tongue for TAS and STO, upper beak, lower beak, angles, and tongue for MAS, and upper beak, lower beak, tongue, and angles for DAS. Mouth lesions were clearly visible with each toxin after feeding for 1 wk and the numbers of affected mouth parts almost tripled after 2 wk exposure. During Week 3 of exposure, only the increase caused by MAS was significant (P less than .05). The MED for growth inhibition were 2, 2, 2, and 8 micrograms/g for STO, MAS, DAS, and TAS, respectively. Thus, mouth lesions were of equal or greater sensitivity than growth inhibition as an indicator of scirpenol toxicity. It would appear that the discovery of mouth lesions in birds justifies a mold and mycotoxin control program.

Effects of a hydrated sodium calcium aluminosilicate on growing turkey poults during aflatoxicosis

Effects of adding .5% of a hydrated sodium calcium aluminosilicate (HSCAS) to diets containing 1 or .5 mg aflatoxin (AF)/kg were determined in male turkey poults from 1 day to 3 wk of age. Body weight gains were significantly reduced by 51 and 19% in turkey poults fed 1 and .5 mg AF/kg, respectively; efficiency of feed utilization was not affected. There were no deaths in poults fed .5 mg AF/kg; however, the mortality rate was 88% in poults fed 1 mg AF/kg. The addition of .5% dietary HSCAS resulted in a 68% decrease in mortality to 28% for the 3-wk experimental period. Treatment-related changes in relative organ weights, hematological values, serum biochemical values, and enzyme activities were observed. The HSCAS in the absence of AF did not alter any of the parameters measured. The HSCAS diminished the adverse effects of AF on body weight gains, most relative organ weights, hematological values, serum biochemical values, and enzyme activities associated with .5 mg AF/kg, but not 1 mg AF/kg. These findings indicate that HSCAS may diminish many of the adverse effects of AF in an AF-sensitive species, the turkey.

An outbreak of aflatoxicosis in Angora rabbits

An outbreak of aflatoxicosis in Angora rabbits involving a large number of rabbitries was investigated. Mortality was more in weaners than in adults. Affected animals showed anorexia, dullness and weight loss followed by jaundice in terminal stages. Death occurred within 3-4 d of the appearance of clinical signs. Livers were moderately to severely congested, icteric and were hard to cut. Gall bladders were distended and had inspissated bile. Liver sections showed degenerative changes of hepatic cells along with dilatation and engorgement of sinusoids. Bile ducts had mild to severe periportal fibrosis. Focal areas of pseudolobulation and regenerative foci were also predominant. The level of aflatoxin B1 in feed samples from various farms submitted at the time of the investigation varied from 90 to 540 ug aflatoxin B1/kg of feed. Withdrawal of feed and supplementary therapy resulted in gradual disappearance of signs and mortality.

Effect of tryptophan supplementation on aflatoxicosis in laying hens

Two experiments were conducted to determine the relationship of supplemental Trp on liver fat accumulation and egg production during aflatoxicosis in laying hens. In Experiment 1, two levels of Trp (0 and 2,000 ppm; basal = .16% Trp) and two levels of aflatoxin (AFLA) (0 and 10 ppm) were supplemented to a complete layer ration. In Experiment 2, a third level of AFLA (5 ppm) was added to the design. Single Comb White Leghorn hens (58 and 68 wk old) were fed the diets for 3 wk for Experiments 1 and 2, respectively. Henday production and egg weights were measured daily. Feed intake was measured weekly. Liver weights, liver moisture, and liver total lipids were determined at the end of each trial. In Experiment 1, supplemental Trp by itself caused a significant (P less than .01) reduction in total liver lipids compared to the controls (no Trp or AFLA). Adding trp and AFLA increased total liver lipids and caused a significant (P less than .05) decrease in egg production compared with adding AFLA alone. Total liver lipids were 41.1, 32.8, 54.8, and 62.4% (dry weight basis) for 0 Trp:0 AFLA, 2,000 Trp:0 AFLA, 0 Trp:10 AFLA, and 2,000 Trp:10 AFLA, respectively. Similar results were observed in Experiment 2. It was concluded that supplemental Trp by itself caused a reduction in total liver lipids, but when supplemented to a diet containing AFLA, Trp caused an increased severity of lesions associated with aflatoxicosis in layers.

Decreased immune response and increased incidence of tibial dyschondroplasia caused by fusaria grown on sterile corn

Corn, feed, and litter samples reported to be associated with feed refusal, diarrhea, leg weakness, and mortality were evaluated for the presence of toxic substances. Intubated residues of ethyl acetate extracts of these samples did not cause gross lesions, diarrhea, or mortality in young New Hampshire x Single Comb White Leghorn crossbred chicks. Fusarium moniliforme was the predominant fungal species found in unpelleted feed and corn samples. Young broiler chicks, fed diets supplemented with 2 or 8% corn cultures of selected F. moniliforme isolates from a suspected toxic corn sample, failed to develop clinical signs of mycotoxicosis. However, some isolates resulted in decreased antibody responses to SRBC. Corn cultures of some Fusarium equiseti and Fusarium semitectum strains also decreased the immune response. Cultures of three F. equiseti strains from barley and potato induced tibial dyschondroplastic lesions in young broiler chicks. Other F. equiseti strains and strains of other Fusarium species did not cause this skeletal abnormality.

Diminution of aflatoxin toxicity to growing lambs by dietary supplementation with hydrated sodium calcium aluminosilicate

Hydrated sodium calcium aluminosilicate (HSCAS), an anticaking agent for mixed feed, was added to the diets of growing wethers (mean body weight, 34.0 kg) and was evaluated for its ability to diminish the clinical signs of aflatoxicosis. The experimental design consisted of 4 treatment groups of 5 wethers each, consuming concentrations of 0 g of HSCAS and 0 g of aflatoxin (AF)/kg of feed (control; group 1); 20 g of HSCAS/kg (2.0%; group 2), 2.6 mg of AF/kg (group 3); or 20 g of HSCAS (2.0%) plus 2.6 mg of AF/kg (group 4). Wethers were maintained in indoor pens, with feed and water available ad libitum for 42 days. Lambs were observed twice daily and weighed weekly, and blood samples were obtained every 2 weeks for hematologic and serum biochemical analyses and for measurement of mitogen-induced lymphocyte-stimulation index. At the termination of the study, wethers were euthanatized and necropsied. Body weight gain was diminished significantly (P less than 0.05) by consumption of 2.6 mg of AF/kg of feed, whereas body weight of lambs consuming HSCAS plus AF did not differ from that of control wethers. The AF-alone treatment increased serum aspartate transaminase and gamma-glutamyltransferase activities, prothrombin time, and cholesterol, uric acid, and triglyceride values and decreased albumin, glucose, and urea nitrogen values, and urea-to-creatine ratio.(ABSTRACT TRUNCATED AT 250 WORDS)