L.W. Whitlow

Aflatoxin binders II: reduction of aflatoxin M1 in milk by sequestering agents of cows consuming aflatoxin in feed.

Sequestering agents bind dietary aflatoxin B1 (AFB1) and reduce absorption from an animals gastrointestinal tract. As a result, they protect an animal from the toxic effects of AFB1 and reduce transfer of the metabolite, aflatoxin M1 (AFM1), into milk. Three experiments, using late-lactation Holstein cows fed AFB1-contaminated feed, were conducted to evaluate several potential sequestering agents for their abilities to prevent or reduce the transmission of AFM1 into milk. Six agents previously tested in our laboratory forAFB1 binding in vitro were evaluated in these experiments. These were: SA-20®, an activated carbon (AC-A); Astra-Ben-20®, a sodium bentonite (AB-20); MTB-100®, an esterified glucomannan (MTB-100); RedCrown®, a calcium bentonite (RC);Flow Guard®, a sodium bentonite (FG); and Mycrosorb®, a sodium bentonite (MS). Five of the six sequestering agents significantly (P < 0.01) reduced AFM1 contamination of milk (AB-20, 61%; FG, 65%; MS, 50%; MTB-100, 59%; and RC, 31%); whereas, AC-A, activated carbon, had no effect on AFM1 transmission at 0.25% of feed. By the first milking (1 day after cows consumed contaminated feed), AFM1 appeared in milk, then reached maximum levels after three days, and was absent from milk within four days after AFB1 was removed from the feed. Sodium bentonites at 1.2% of feed showed good potential asAFB1 binders; MTB-1OO, a yeast cell wall product, was equally effective at 0.05% in feed. PotentialAFB1 binding agents should be evaluated experimentally to demonstrate efficacy. Our data show that sequestering agents can reduce AFM1 in milk of cows fed AFB1-contaminated feed.

Aflatoxin Binders I: In vitro binding assay for aflatoxin B1 by several potential sequestering agents

Nine potential proprietary sequestering agents consisting of 4 activated charcoals, 3 sodium bentonites, a calcium bentonite, and an esterified glucomannan were compared in a novel in vitro assay for aflatoxin B1 (AFB1) binding. Agents were evaluated in 10% methanol prepared as 1% stirred suspensions at pH 3, 7, 10 and pH-unadjusted, with or without AFB1 at 5 μg/ml. All nine agents bound more than 95% of the 5 μg of AFB1 in solution, regardless of pH. The sodium bentonites bound 98, 95, and 98% of the AFB1. The four activated charcoals bound over 99%, the calcium bentonite bound 98%, and the esterified glucomannan bound 97% of the AFB1 in solution. The results suggested that the sequestering agents tested here had sufficient potential to bind AFB1 at pH values commonly found in the gastrointestinal tracts of ruminants and other animals.

Effect of physical damage to ears of corn before harvest and treatment with various additives on the concentration of mycotoxins, silage fermentation, and aerobic stability of corn silage.

We studied the effects of damaging ears of corn in the field prior to harvest and the use of various additives on the production of selected mycotoxins, silage fermentation, and aerobic stability of whole plant corn. In experiment 1, ears of corn were undamaged or were slashed with a knife 7 d before harvesting, exposing damaged kernels to the environment. Corn plants were harvested (about 35% DM) and treated in a 2 × 2 factorial arrangement of treatments. Treatments were undamaged or damaged plants, untreated or treated with Lactobacillus buchneri 40788 (400,000 cfu/g of fresh forage) and Pediococcus pentosaceus (100,000 cfu/g). Damaging ears prior to harvest increased the amount of fumonisin but decreased the amount of starch in harvested corn plants. After ensiling, corn silage made from plants damaged before harvest had lower starch but greater concentrations of deoxynivalenol and fumonisin than silage made from plants that were undamaged. Microbial inoculation resulted in fewer yeasts and lower concentrations of zearalenone in silage when compared to uninoculated silage. Inoculated silage also had more acetic acid and 1,2-propanediol than did uninoculated silage. In experiment 2, ears of corn were undamaged or were slashed with a knife 27 d or 9 d before harvesting for corn silage. Whole plants were harvested at about 36% DM in a 2 × 3 factorial arrangement of treatments. Factors were time of damaging the ears (27 d, 9 d, or no damage) relative to harvest and no additive or 0.1% (fresh weight) potassium sorbate. Damaging plants 9 d prior to harvest did not affect the concentrations of deoxynivalenol, fumonisin, and zearalenone in plants at harvest. However, concentrations of deoxynivalenol and fumonisin were increased in fresh forage that had ears damaged at 27 d when compared to corn plants that were undamaged. Corn plants damaged for 27 d prior to harvest also had a lower concentration of starch than corn damaged for 9 d but was higher in acid detergent fiber than other treatments. The addition of potassium sorbate at harvest had no effect on the concentrations of mycotoxins in the resulting silage, but concentrations of mycotoxins were still greatest in silage made from plants that were damaged the longest prior to harvest (27 d). Silages treated with potassium sorbate had fewer yeasts and molds than silages without the additive. Damaging ears of corn before harvest had no effects on the aerobic stability of silages in both experiments. In contrast, the addition of the inoculant and potassium sorbate improved aerobic stabilities of silages when compared to untreated silages. These studies showed that physical damage to ears of corn prior to harvest can result in the production of mycotoxins in the field. This finding suggests that producers should test corn silage for mycotoxins prior to feeding especially if the forage has been subjected to physical damage prior to ensiling.

The addition of cottonseed hulls to the starter and supplementation of live yeast or mannanoligosaccharide in the milk for young calves

The objectives of this study were to investigate the effects of the addition of cottonseed hulls (CSH) to the starter and the supplementation of live yeast product (YST) or mannanoligosaccharide product (MOS) to milk, on growth, intake, rumen development, and health parameters in young calves. Holstein (n = 116) and Jersey (n = 46) bull (n = 74) and heifer (n = 88) calves were assigned randomly within sex at birth to treatments. All calves were fed 3.8 L of colostrum daily for the first 2 d. Holstein calves were fed 3.8 L of whole milk, and Jersey calves were fed 2.8 L of whole milk through weaning at 42 d. Calves continued on trial through 63 d. Six treatments were arranged as a 2 x 3 factorial. Calves received either a corn-soybean meal-based starter (21% crude protein and 6% acid detergent fiber; -CSH) or a blend of 85% corn-soybean meal-based starter and 15% CSH (18% crude protein and 14% acid detergent fiber; +CSH) ad libitum. In addition, calves received whole milk with either no supplement (NONE) or supplemented with 3 g/d of mannanoligosaccharide product (MOS) or 4 g/d of live yeast product (YST) through weaning at 42 d. Twelve Holstein steers [n = 6 (per starter type); n = 4 (per supplement type)] were euthanized for collection and examination of rumen tissue samples. Dry matter intake (DMI) was greater for Holstein calves fed +CSH (0.90 kg/d) than -CSH (0.76 kg/d). Final body weight at 63 d of Holstein calves fed +CSH (75.8 kg) was greater than that of those fed -CSH (71.0 kg). Average daily gain (ADG) was greater for Holstein calves fed +CSH (0.58 kg/d) than -CSH (0.52 kg/d). However, Holstein calves fed -CSH had a greater feed efficiency (FE; 0.71 kg of ADG/kg of DMI) than those fed +CSH (0.65 kg of ADG/kg of DMI). Also, Holstein calves fed +CSH had narrower rumen papillae (0.32 mm) compared with those fed -CSH (0.41 mm). There were no significant effects of CSH on DMI, ADG, or FE in Jersey calves. There were no significant effects of YST or MOS on DMI, ADG, FE, or rumen papillae measures in Holstein calves. Jersey calves fed YST or MOS had greater final body weight at 63 d (51.2 kg and 51.0 kg, respectively) than calves fed NONE (47.5 kg). However, there were no significant effects of YST or MOS on DMI, ADG, or FE in Jersey calves.

The Association of Deoxynivalenol in Grain with Milk Production Loss in Dairy Cows

Reports have indicated that in certain geographical locations and in certain years there can be a high incidence of feedstuffs contaminated with aflatoxin (Nichols 1983), deoxynivalenol (DON) (Vesonder et al., 1978; Mirocha, 1974), zearalenone (Shotwell et al., 1980) or ochratoxin A (Hamilton et al., 1982). The practical importance of these and other mycotoxins in feedstuffs which have the potential of affecting the health and productivity of farm animals is a topic of intensive investigation. The significance of DON-contamination of poultry and dairy feedstuffs is particularly controversial.

Effects of Moldy Cottonseed on Reproduction in Beef and Dairy Heifers

Weather conditions before harvest and storage conditions after harvest contribute to growth of molds and subsequent production of mycotoxins in various commodity feeds. Although numerous mycotoxins have been identified, information on adverse effects on farm animals is often speculative, or based only on case studies and field observations. This is particularly true for suspected mycotoxicoses in ruminants.