The individual and combined effects of feeding diets containing 300 mg fumonisin B1 (FB1), and 5 mg T-2 toxin (T-2)/kg of diet, or 15 mg/kg deoxynivalenol (DON, vomitoxin) from naturally contaminated wheat were evaluated in two studies in male broiler chicks from day of hatch to 19 or 21 d of age in Experiments 1 and 2, respectively. When compared with controls, body weight gains were reduced 18 to 20% by FB1, 18% by T-2, 2% by DON, 32% by the FB1 and T-2 combination, and 19% by the FB1 and DON combination. The efficiency of feed utilization was adversely affected by FB1 with or without T-2 or DON. Mortality ranged from none for the controls to 15% for the FB1 and T-2 combination. Relative weights of the liver and kidney were significantly increased by FB1 with or without T-2 or DON. Serum concentrations of cholesterol were increased in chicks fed FB1 with or without T-2 or DON. Activities of aspartate aminotransferase, lactate dehydrogenase, and gamma glutamyltransferase were increased in chicks fed FB1 at 300 mg/kg alone and in combination with T-2 or DON, indicating possible tissue damage and leakage of the enzymes into the blood. Results indicate additive toxicity when chicks were fed diets containing 300 mg FB1 and 5 mg T-2/kg of diet and less than additive toxicity when chicks were fed 300 mg FB1 and 15 mg DON/kg of diet. Of importance to the poultry industry is the fact that toxic synergy was not observed for either of these toxin combinations and the likelihood of encountering FB1 at this concentration in finished feed is small. However, under field conditions with additional stress factors, the toxicity of these mycotoxins could be altered to adversely affect the health and performance of poultry.

Experiments were conducted to determine the ability of a hydrated sodium calcium aluminosilicate (T-Bind) sorbent to reduce the toxicity of aflatoxins (AF) or T-2 toxin in male broiler chickens from day of hatch to 21 d of age. In Experiment 1, the sorbent was added at 0.250 or 0.375% to diets containing AF at 5 or T-2 toxin at 8 mg/kg of diet. When compared with controls, AF reduced BW gain by 27% and T-2 toxin reduced BW gain by 17%. The addition of the sorbent at 0.250 or 0.375%, in the absence of added mycotoxins, did not alter the performance of the chicks. The sorbent reduced the toxic effects of 5 mg AF/kg of diet on BW gain by 43% but did not significantly diminish the toxic effects of 8 mg T-2 toxin/kg of diet. The decreased efficiency of feed utilization and the increased relative organ weights caused by AF were significantly diminished to differing degrees by the sorbent. Oral lesions caused by T-2 toxin were not affected by the sorbent. In Experiment 2, the sorbent was added at 0.80% to a diet containing 8 mg T-2 toxin/kg of diet. The sorbent did not diminish the toxic effects of T-2 toxin when added at 0.80% of the diet. These data demonstrate that this specific sorbent can provide protection against the toxicity of AF, but not T-2 toxin, in young broiler chicks.

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).

Monoclonal antibodies were developed that bind sarafloxacin, a fluoroquinolone approved by the Food and Drug Administration for use against Escherichia coli in poultry. Splenocytes from mice immunized with a bovine serum albumin−sarafloxacin conjugate were fused with SP2/0 myeloma cells, and hybridomas secreting antibodies against sarafloxacin were selected and cloned. An enzyme-linked immunoassay was developed, and 50% inhibition of control values ranged from 7.3 to 48.3 ppb using sarafloxacin as the competitor. Tissue samples were spiked with sarafloxacin, and the average percent recoveries at 10, 50, and 100 ppb were 132, 78, and 81%, respectively. Monoclonal antibodies exhibiting high relative affinity for sarafloxacin were also characterized for their ability to detect five structurally related quinolones. The specificity and cross-reactivities of these antibodies are discussed in relation to three-dimensional, computer-generated molecular models of the fluoroquinolones. Keywords: Sarafloxacin; fluoroquinolone; ELISA; immunoassay