Search Results

You are looking at 1 - 9 of 9 items for :

  • Refine by Access: All Content x
Clear All

SUMMARY

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 < 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 γ-glutamyltransferase activities, prothrombin time, and cholesterol, uric acid, and triglyceride values and decreased albumin, glucose, and urea nitrogen values, and urea-to-creatine ratio. A 27% decrease in lymphocyte stimulation index, increased spleen weight (as a percentage of body weight), and decreased liver weight were induced by af-alone treatment. Results indicate that hscas may be a high-affinity sorbent for af, that 2.6 mg of af/kg of feed induces signs of aflatoxicosis in growing wethers, that lambs may not be as resistant to the effects of af as previously thought, that 2.0% hscas can substantially reduce the toxic effects of 2.6 mg of af/kg, and that sorbent compounds may offer a novel approach to the preventive management of aflatoxicosis in livestock.

Free access
in American Journal of Veterinary Research

Summary

Hydrated sodium calcium aluminosilicate (hscas), an anticaking agent for agricultural feeds, was added to aflatoxin (af)-contaminated diets of 3 lactating dairy cows and evaluated for its potential to reduce aflatoxin M1 (afm 1) residues in milk. During phase I, cows were fed alternating diets that consisted of 200 μg of af/kg of feed for 7 days, 0.5% hscas plus 200 μg of af/kg of feed for 7 days, and feed with the hscas removed for a final 7 days. The afm 1 milk concentrations from the intervals with hscas added to diets were compared with those times when hscas was absent. The presence of 0.5% hscas in feed containing 200 μg of af/kg reduced afm 1 secretion into the milk by an average of 0.44 μg/L (from pretreatment of 1.85 μg/L to 1.41 μg/L with hscas, a 24% reduction). Following a 10-day period of noncontaminated feed consumption and no afm 1 residues in the milk, phase II of the study was begun. The same experimental design as phase I was used, but the dosages of hscas and af were changed to 1.0% and 100 μg/kg of feed, respectively. The addition of 1.0% hscas in feed containing 100 μg of af/kg decreased afm 1 content in the milk by an average of 0.40 μg/L (from a pretreatment of 0.91 μg/L to 0.51 μg/L when hscas was present, a 44% reduction). These findings suggest that hscas, a high-affinity sorbent compound for af in vitro, is capable of reducing the secretion of afm 1 into milk.

Free access
in American Journal of Veterinary Research

Summary

The study reported here was part of a long-term investigation of the effects of genotype on growth, reproduction, and metabolism in cattle grazing common Bermuda grass and endophyte-infected fescue pastures. In June 1990, blood samples were collected from the tail vein of yearling heifers and steers (Angus [aa], Brahman [bb], and their reciprocal crosses [ab, ba], n = 97). Serum amylase activity was assayed enzymatically; serum Ca and Mg concentrations were determined by atomic absorption spectrophotometry. The effects of endophyte-infected fescue depended on genotype (P < 0.001). In yearlings having at least 1 Angus parent (aa, ab, ba), grazing endophyte-infected fescue was associated with higher serum amylase activity than was grazing Bermuda grass. But serum amylase activities of bb yearlings consuming either forage were similar. Moreover, for either forage, substantial differences were related to genotype (P < 0.007) and gender (P < 0.05). Angus yearlings had higher serum amy-lase activity than did Brahman yearlings; ab and ba yearlings had intermediate values. Heifers had higher amylase activity than did steers. The relationship among serum values of amylase, Ca, and Mg depended on forage. Yearlings consuming endophyte-infected fescue and hav-ing at least 1 Angus parent had a moderate negative correlation between serum amylase activity and Ca concentration (r = —0.53; P < 0.0005); that is, in calves of genotypes with increased amylase activity while consuming endophyte-infected fescue (aa, ab, ba), the higher the amylase activity, the lower the serum Ca concentration. However, in yearlings consuming Bermuda grass, serum amylase and Ca values were not correlated. Conversely, grazing Bermuda grass was associated with moderate positive correlation between Ca and Mg concentrations (r = 0.46; P < 0.0003), but in yearlings grazing endophyte-infected fescue, Ca and Mg concentrations were independent. The cause, pathophysiologic mechanism, and clinical importance of these effects remain to be determined. In conclusion, serum amylase activity in yearling cattle was influenced by genotype, gender, and consumption of endophyte-infected fescue. We speculate that yearlings having at least 1 Angus parent may develop a persistent subclinical derangement of the exocrine portion of the pancreas when exposed to common environmental toxins associated with endophyte-infected fescue grass, and that purebred Brahman yearlings can resist this aspect of fescue toxicosis.

Free access
in American Journal of Veterinary Research

Summary

An in vitro bioassay system was used to study the effects of cyclopiazonic acid (cpa) mycotoxin on cardiac muscle. Acute exposure to 6 μg of cpa/ml of modified Krebs-Henseleit solution significantly (P < 0.05) decreased 5 in vitro turkey cardiac muscle performance criteria: maximal weight a muscle could lift; maximal contraction velocity; relaxation velocity; time to peak contraction; and total time for muscle contraction and relaxation. The effect on these 5 criteria appeared to result from intracellular changes partially associated with calcium availability and were irreversible, suggesting that physiologic changes had developed after acute exposure to cpa.

Free access
in American Journal of Veterinary Research

SUMMARY

Effects of dietary aflatoxin (af) and T-2 toxin, singly and in combination, were evaluated in growing crossbred (Yorkshire × Landrace × Hampshire) pigs. The experimental design consisted of 4 treatment groups of 6 barrows each fed diets containing 0 mg of af and T-2/kg of feed (controls; group 1), 2.5 mg of af/kg of feed (group 2), 10 mg of T-2/kg of feed (group 3), or 2.5 mg of af plus 10 mg of T-2/kg of feed (af + T-2; group 4) ad libitum for 28 days (7 to 11 weeks of age). Production performance, and serum biochemical, and hematologic evaluations were made weekly. Body weight and body weight gain were depressed by all toxin treatments, but the effect of af and T-2 toxin in combination was less than additive. Liver and kidney weights, as a percentage of body weight, were increased by af treatment, and heart weight, as a percentage of body weight, was increased by T-2 treatment. Treatment with T-2 toxin induced necrotizing contact dermatitis on the snout, buccal commissures, and prepuce. Consumption of af resulted in increased serum activities of alkaline phosphatase, aspartate transaminase, cholinesterase, and γ-glutamyltransferase, and decreased serum concentrations of urea nitrogen, cholesterol, albumin, total protein, calcium, potassium, magnesium, and phosphorus. Consumption of T-2 toxin resulted in increased serum triglyceride concentration and decreased serum iron concentration. Treatment with af induced lower serum unsaturated iron-binding capacity and high rbc count, pcv, hemoglobin concentration, wbc count, and prothrombin time. Treatment with T-2 toxin induced microcytic hypochromic anemia, increased numbers of circulating metarubricytes and decreased absolute numbers of lymphocytes. Hepatocellular lesions in barrows of the af and the af plus T-2 groups (2 and 4, respectively) were compatible with aflatoxicosis. When fed in combination, each toxin appeared to have a sparing action on certain effects of the other, and the responses elicited were either additive or less than additive.

Free access
in American Journal of Veterinary Research

Summary

Effects of dietary aflatoxin (af) and supplemental Vitamin E (d-α-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, γglutamyltransferase, 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.

Free access
in American Journal of Veterinary Research

Summary

4-Methylpyrazole (4-mp), an alcohol dehydrogenase inhibitor, was administered to dogs to treat ethylene glycol (eg) intoxication. Eleven dogs were given 10.6 g of eg/kg of body weight; 5 dogs were treated with 4-mp 5 hours after eg ingestion and 6 dogs were treated with 4-mp 8 hours after eg ingestion. 4-Methylpyrazole was administered iv as a 50-mg/dl solution in 50% polyethylene glycol: initial dose, 20 mg/kg; at 12 hours after initial dose, 15 mg/kg; at 24 hours after initial dose, 10 mg/kg; and at 30 hours after initial dose, 5 mg/kg. Physical, biochemical, hematologic, blood gas, serum and urine eg concentrations, and urinalysis findings were evaluated at 0, 1, 3, 6, 9, 12, 24, 48, 72 hours, and at 1 week and 2 weeks after eg ingestion.

Dogs of both groups developed clinicopathologic signs associated with eg intoxication, including cns depression, hyperosmolality, high anion gap metabolic acidosis, polydipsia, polyuria, calcium oxalate monohydrate and dihydrate crystalluria, and isosthenuria. Fractional excretion of sodium was increased in all dogs between 1 and 9 hours after eg ingestion, but remained increased beyond 24 hours only in the 2 dogs treated at 8 hours after eg ingestion that developed acute renal failure. All dogs treated 5 hours after eg ingestion recovered without morphologic, biochemical, or clinical evidence of renal impairment. Of the 6 dogs treated 8 hours after eg ingestion, 2 developed acute renal failure. One of the dogs treated 8 hours after eg ingestion remained isosthenuric for 2 months, but did not manifest any other signs of renal impairment. Of the dogs treated 8 hours after eg ingestion, 3 recovered without morphologic, biochemical, or clinical evidence of renal impairment. Serum half-life of eg was prolonged in the dogs treated 8 hours after eg ingestion. Percentage of eg excreted unchanged was 84 ± 2% in the dogs treated 5 hours after eg ingestion, and was 40 ± 10% in the dogs treated 8 hours after eg ingestion. 4-Methylpyrazole was effective in preventing renal failure in all dogs given 10.6 g of eg/kg when treatment was initiated by 5 hours after eg ingestion, and in 4 of 6 dogs when treatment was initiated by 8 hours after eg ingestion.

Free access
in American Journal of Veterinary Research

= moderate inflammation, and 3 = severe inflammation.) Special stains for calcium (von Kossa stain) and iron (Perl Prussian blue stain) were perfomed on 1 section from each skeletal muscle specimen. Degree of staining was graded and assigned a score (0 = no

Full access
in American Journal of Veterinary Research

Serum concentrations of total protein, albumin, globulin, glucose, cholesterol, urea, creatinine, calcium, phosphorus, magnesium, sodium, potassium, chloride, carbon dioxide, bilirubin, and cortisol and activities of alkaline phosphatase, aspartate

Full access
in American Journal of Veterinary Research