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Three experiments were conducted to determine the effects of 4,15-diacetoxyscirpenol (DAS) on BW, feed consumption, and oral lesions of broiler breeders. In Experiment 1, caged broiler breeder hens were fed 0, 5, 10, or 20 mg DAS/kg diet from 24 to 25 wk of age. There were dose-related decreases in BW and feed consumption indicating feed refusal, as well as dose-related increases in the extent of mouth lesions. The areas of the mouth most sensitive to DAS were associated with the salivary glands and the tip of the tongue. In Experiment 2, individually caged male and female broiler breeders were fed a basal diet containing 0, 5, 10, or 20 mg DAS/kg from 25 to 27 wk of age. There were dose-related decreases in BW and feed consumption for the female broiler breeders, whereas there was a decrease in feed consumption for the male broiler breeders at the 10 and 20 mg DAS/kg levels. In Experiment 3, male broiler breeders were fed 0 or 10 mg DAS/kg diet from 23 to 25 wk of age on a litter floor. For this experiment the daily intake of feed was restricted, and the feed consumption rate was measured. There was an increased amount of unconsumed feed at 23 wk of age due to the presence of DAS. In summary, the experiments provided evidence that DAS caused decreased BW and feed consumption as well as cytotoxic injury including oral lesions in broiler breeders.

Two experiments were conducted to determine the effects of 4,15-diacetoxyscirpenol (DAS) on fertility and hatchability of broiler breeders. In Experiment 1, naturally mated broiler breeders were studied. A limited daily allocation of feed containing 0 (basal), 1.25, 2.5, or 5.0 mg DAS/kg diet was provided from 67 to 69 wk of age in slat-litter floor pens. Fertility was consistently improved by the 5.0 mg/kg level of DAS and intermittently by the 1.25 and 2.50 mg/kg levels. The effect disappeared upon removal of DAS. In Experiment 2, individually caged broiler breeder males and females were fed a basal diet containing 0, 5, 10, or 20 mg DAS/kg diet from 25 to 27 wk of age. Semen was pooled from males within each treatment and used to inseminate females from each treatment in a 4 x 4 factorial design. Female-related fertility was increased at the 5 and 10 mg DAS/kg levels and male-related fertility was decreased by the 10 and 20 mg DAS/kg levels. Small, fluid-filled cysts were observed on the testes of many DAS-treated males upon necropsy. In summary, low levels of DAS (or =10 mg DAS/kg) appeared to improve female-related fertility, presumably because of enhanced spermatozoal storage within the oviduct. Conversely, DAS (or =10 mg DAS/kg) decreased male-related fertility, presumably by direct toxic effects on the testes. Overall, it appeared that levels of DAS below 5 mg DAS/kg feed would not be detrimental to fertility and hatchability.

The individual and combined effects of feeding diets containing 300 mg fumonisin B1 (FB1), and 4 mg diacetoxyscirpenol (DAS) or 3 mg ochratoxin A (OA) were evaluated in two experiments using female turkey poults (Nicholas Large Whites) from day of hatch to 3 wk of age. When compared with controls, body weight gains were reduced 30% (Study 1) and 24% (Study 2) by FB1, 30% by DAS, 8% by OA, 46% by the FB1 and DAS combination, and 37% by the FB1 and OA combination. The efficiency of feed utilization was adversely affected by all treatments except FB1 in Experiment 2. Relative weights of the liver were significantly increased by all treatments except the DAS treatment. Serum concentrations of cholesterol were decreased and activities of aspartate aminotransferase and lactate dehydrogenase were increased and several hematological values were altered in poults fed FB1 alone and in combination with either DAS or OA. Results indicate additive or less than additive toxicity, but not toxic synergy, when poults are fed diets containing 300 mg FB1, and 4 mg DAS or 3 mg OA/kg of diet. The likelihood of encountering FB1, DAS, or OA at these concentrations in finished feed is small. However, under field conditions, other stress factors could alter the impact of these mycotoxins on the health and performance of poultry.

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.

Scirpentriol (STO) and its seven acetylated derivatives, 3-, 4- and 15-monoacetoxyscirpenol (MAS), 3,4-, 3,15-, and 4,15-diacetoxyscirpenol (DAS), and 3,4,15-triacetoxyscirpenol (TAS) were compared for their acute oral lethality in broiler chicks, lethality in brine shrimp, and dermal toxicity in guinea pigs. Of the eight toxins, 4,15-DAS was the most toxic in the three assays, 3-MAS was the least toxic in brine shrimp and dermal assays, and 3,4-DAS was the least toxic in the chick assay. There was a difference of about a 100-fold and 20-fold, respectively, between 4,15-DAS and 3-MAS in dermal toxicity and brine-shrimp toxicity, as well as a difference of more than 16-fold between 4,15-DAS and 3,4-DAS in chick toxicity. In general, a free hydroxy group at the 3-position was a primary determinant of toxicity. Toxicity in the scirpenol family did not follow precisely the pattern reported earlier for the T-2 toxin family of trichothecene toxins, in which a decrease in the number of acyl groups was accompanied by a decrease in toxicity. At necropsy, the predominant sign in chicks was petechial hemorrhaging, primarily in the gastrointestinal tract and in the vascular beds of the beaks and the toe nails. The 4,15-DAS and 15-MAS were about 3 times more toxic in chicks than aflatoxin. All members of the scirpenol family of trichothecene mycotoxins appeared sufficiently toxic to warrant attention whenever field outbreaks occur. Apparently, brine shrimp and dermal assays are successful predictors of chick lethality by the more toxic trichothecenes and are less suitable for predicting the activity of the less toxic trichothecenes.

Three experiments were conducted to determine the effects of 4,15-diacetoxyscirpenol (DAS) on egg quality and egg production of broiler breeders. In Experiment 1, feed containing 0, 1.25, 2.5, or 5.0 mg DAS/ kg was fed from 67 to 69 wk of age followed by a 3-wk recovery period on a slat-litter floor. In Experiment 2, individually caged broiler breeder females were studied from 23 to 31 wk of age. The basal diet containing 0, 5, 10, or 20 mg DAS/kg was fed from 25 to 27 wk of age. In Experiment 3, individually caged broiler breeder hens were studied from 23 to 32 wk of age. DAS was fed at levels of 0 (basal), 5, 10, and 20 mg DAS/kg for 2 wk beginning at Week 24, followed by the basal breeder diet for 7 wk. Egg production was not affected by levels of up to 5 mg DAS/kg in the older hens of Experiment 1. When fed from 25 to 27 wk of age in Experiment 2, DAS decreased egg production at the 20 mg/kg level only. When fed from 24 to 25 wk of age in Experiment 3, DAS had no significant effect on egg production or egg quality. Short-term consumption of DAS at levels that might naturally occur appears to have little effect on broiler breeder egg production.

A hydrated sodium calcium aluminosilicate (HSCAS) was incorporated into diets (.5%) containing 3.5 mg/kg aflatoxin (AF) and 5.0 mg/kg diacetoxyscirpenol (DAS) singly and in combination. Male broiler chicks received ad libitum access to their respective diets and water from 1 to 21 days of age. Body weight gains were significantly (P < .05) depressed by AF and DAS singly and a synergistic interaction occurred between AF and DAS for a further depression of body weight gains. Alterations in hematological and serum biochemical values, as well as serum enzyme activities, were observed for the AF and the AF and DAS combination. Additionally, a significant interaction occurred between AF and DAS for some biochemical values and enzyme activities. Adding HSCAS resulted in almost total protection against the effects caused by AF alone, limited protection against the combination, but no protection against the DAS alone. These findings indicate that HSCAS can diminish the adverse effects of AF but not of DAS.

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.

Research on feed refusal syndrome(s), an important problem in the poultry industry, has been hindered by a lack of sensitive and quantitative laboratory models. Suitable models were developed using five groups of 30-week-old male chickens per treatment. Feed or water, depending on which was to be measured, was withdrawn overnight. Then consumption of treated water or feed was measured over a 6-hr period of rehydration or refeeding. In aqueous solutions NaCl, H2SO4, and Na2CO3 reduced liquid consumption in a dose-related manner. Ammonia caused a similar refusal when added to feed. Consumption of feed and water was not influenced by pH over the ranges likely to occur as a result of fungal activity. Consumption of feed on a wet weight, but not dry weight, basis was influenced by the moisture content of feed. A culture filtrate of Fusarium roseum NRRL 1181 containing diacetoxyscirpenol, a trichothecene mycotoxin, reduced consumption of feed by about 77% when added to feed and reduced liquid consumption by about 92% when substituted for drinking water. Thus, the models for consumption of liquids and solids appear to have the attributes necessary for quantitative investigation into the relationships of mycotoxins to feed refusal syndromes.

The cause of feed refusal by poultry is an important problem that has not been established. T-2 toxin, a culture filtrate of Fusarium roseum NRRL 1181 containing a high concentration of diacetoxyscirpenol, and a filtrate of Penicillium citrinum containing an unknown factor produced refusal activity in week-old chickens. Citrinin stimulated water consumption while aflatoxin did not affect feed consumption. Detection of refusal activity was more sensitive when the refusal factor was presented in the drinking water than in the feed. The experimental model used here was sensitive, and, with appropriate controls, would appear suitable for the isolation and study of new factors capable of causing feed refusal in poultry.

The refusal by young chickens of feed containing graded levels (0, 1.25, 2.5, 5.0, 10.0, 20.0, and 40.0 micrograms/g of diet) of the Fusarium mycotoxins scirpentriol (STO), monoacetoxyscirpenol (MAS), diacetoxyscirpenol (DAS), and triacetoxyscirpenol (TAS) was tested in a defined experimental model. The order of activity as measured by minimum effective dose was DAS greater than MAS = STO greater than TAS whereas the order measured by percentage refusal at 10, 20, and 40 micrograms/g was MAS greater than DAS greater than STO greater than TAS. These results imply that feed refusal associated with corn and feed infested with Fusarium sps. might be a multiple toxicosis because the scirpenols, which are not tested for routinely, can occur together naturally.

White Leghorn females in egg production (36 weeks old) were fed a culture of Fusarium roseum containing 15 ppm diacetoxyscirpenol (DAS) and other unidentified toxins at culture levels of 0, 1, and 2% of the diet for 8 weeks. Following this, all hens were placed on control (0% toxins) feed for 6 weeks. Birds were inseminated weekly with .05 ml of pooled semen from males given normal diets. The F. roseum had no significant effect on body weight change or egg weights. During the initial 8 weeks, egg production was significantly depressed by both the 1 and 2% levels whereas feed consumption, fertility, and hatchability of fertile eggs was reduced only by the 2% level of F. roseum. Moreover, the majority of embryo mortality occurred prior to the 7th day of incubation. All production levels returned to normal when the toxins were removed during the final 6 weeks. In a second experiment, control (0%), .5 ppm purified DAS, and 3% F. roseum culture were fed to White Leghorn females (50 weeks old) for 4 weeks followed by a 2-week withdrawal period when all birds were given control diets. In 4 weeks, hatchability of fertile eggs was reduced 24% by DAS and 99% by the culture of F. roseum but returned to normal after the toxins were removed. Other production indices were unaffected by dietary treatment. The DAS appears to be only partially responsible for the reduced hatchability; the major toxicant has not been identified.

One-day-old broiler chicks were fed a diet containing either 5 ppm diacetoxyscirpenol (DAS), 5 ppm T-2 toxin, 10 ppm crotocin, or a control diet for 3 weeks. Chicks fed the diet containing DAS and T-2 toxin showed yellowish plaque-type lesions on the beak, tongue, and angle of the mouth. Crotocin did not cause such lesions nor any apparent clinical signs. Chicks fed DAS had the lowest weight gain followed by the T-2, crotocin, and control group in that order; however, chicks fed crotocin had the poorest feed conversion ratio.