Joelma Lucioli

Chronic ingestion of deoxynivalenol and fumonisin, alone or in interaction, induces morphological and immunological changes in the intestine of piglets

Deoxynivalenol (DON) and fumonisins (FB) are mycotoxins produced by Fusarium species, which naturally co-occur in animal diets. The gastrointestinal tract represents the first barrier met by exogenous food/feed compounds. The purpose of the present study was to investigate the effects of DON and FB, alone and in combination, on some intestinal parameters, including morphology, histology, expression of cytokines and junction proteins. A total of twenty-four 5-week-old piglets were randomly assigned to four different groups, receiving separate diets for 5 weeks: a control diet; a diet contaminated with either DON (3 mg/kg) or FB (6 mg/kg); or both toxins. Chronic ingestion of these contaminated diets induced morphological and histological changes, as shown by the atrophy and fusion of villi, the decreased villi height and cell proliferation in the jejunum, and by the reduced number of goblet cells and lymphocytes. At the end of the experiment, the expression levels of several cytokines were measured by RT-PCR and some of them (TNF-α, IL-1β, IFN-γ, IL-6 and IL-10) were significantly up-regulated in the ileum or the jejunum. In addition, the ingestion of contaminated diets reduced the expression of the adherent junction protein E-cadherin and the tight junction protein occludin in the intestine. When animals were fed with a co-contaminated diet (DON+FB), several types of interactions were observed depending on the parameters and segments assessed: synergistic (immune cells); additive (cytokines and junction protein expression); less than additive (histological lesions and cytokine expression); antagonistic (immune cells and cytokine expression). Taken together, the present data provide strong evidence that chronic ingestion of low doses of mycotoxins alters the intestine, and thus may predispose animals to infections by enteric pathogens.

Individual and combined effects of subclinical doses of deoxynivalenol and fumonisins in piglets

SCOPE Deoxynivalenol (DON) and fumonisins (FB) are the most frequently encountered mycotoxins produced by Fusarium species and most commonly co-occur in animal diets. These mycotoxins were studied for their toxicity in piglets on several parameters including plasma biochemistry, organ histopathology and immune response. METHODS AND RESULTS Twenty-four 5-wk-old animals were randomly assigned to four different groups, receiving separate diets for 5 wk, a control diet, a diet contaminated with either DON (3 mg/kg) or FB (6 mg/kg) or both toxins. At days 4 and 16 of the trial, the animals were subcutaneously immunized with ovalbumin to assess their specific immune response. The different diets did not affect animal performance and had minimal effect on hematological and biochemical blood parameters. By contrast, DON and FB induced histopathological lesions in the liver, the lungs and the kidneys of exposed animals. The liver was significantly more affected when the two mycotoxins were present simultaneously. The contaminated diets also altered the specific immune response upon vaccination as measured by reduced anti-ovalbumin IgG level in the plasma and reduced lymphocyte proliferation upon antigenic stimulation. Because cytokines play a key role in immunity, the expression levels of IL-8, IL-1β, IL-6 and macrophage inflammatory protein-1β were measured by RT-PCR at the end of the experiment. The expression of these four cytokines was significantly decreased in the spleen of piglets exposed to multi-contaminated diet. CONCLUSION Taken together, our data indicate that ingestion of multi-contaminated diet induces greater histopathological lesions and higher immune suppression than ingestion of mono-contaminated diets.

Biotransformation approaches to alleviate the effects induced by fusarium mycotoxins in swine.

Mycotoxin mitigation is of major interest as ingestion of mycotoxins results in poor animal health, decreased productivity, as well as substantial economic losses. A feed additive (FA) consisting of a combination of bacteria (Eubacterium BBSH797) and enzyme (fumonisin esterase FumD) was tested in pigs for its ability to neutralize the effects of mono- and co-contaminated diets with deoxynivalenol (DON) and fumonisins (FB) on hematology, biochemistry, tissue morphology, and immune response. Forty-eight animals, allocated into eight groups, received one of eight diets for 35 days: a control diet, a diet contaminated with either DON (3 mg/kg) or FB (6 mg/kg), or both toxins, and the same four diets with FA. Inclusion of FA restored the circulating number of neutrophils of piglets fed the FB and DON + FB diets. Similarly, FA counteracted the minor changes observed on plasma concentrations of albumin and creatinine. In lung, the lesions induced by the ingestion of FB in mono- and co-contaminated diets were no longer observed after addition of FA in these diets. Lesions recorded in the liver of pigs fed either of the contaminated diets with FA were partly reduced, and the increased hepatocyte proliferation was totally neutralized when FA was present in the co-contaminated diet. After 35 days of exposure, the development of the vaccinal response was significantly improved in animals fed diets supplemented with FA, as shown by results of lymphocyte proliferation, cytokine expression in spleen, and the production of specific Ig. Similarly, in jejunum of animals fed diets with FA, occurrence of lesions and upregulation of pro-inflammatory cytokines were much less obvious. The ameliorative effects provided by FA suggest that this approach would be suitable in the control of DON and FB that commonly co-occur in feed.

Conidiobolomicose causada por Conidiobolus lamprauges em ovinos no Estado de Santa Catarina

An outbreak of conidiobolomycosis affecting sheep in the State of Santa Catarina, Southern Brazil is reported. The disease occurred in six Santa Ines breed sheep from a flock of 75 during the rainy season. Common clinical signs were noisy respiration and dyspnea, serous to mucosanguineous nasal discharge and exophthalmus. At necropsy there was a dense yellow mass in the nasopharyngeal area affecting the ethmoidal region, turbinate bones and occasionally limph nodes, central nervous system and pleura. Histopathologycally there was multifocal granulomas whith an eosinophilic necrotic reaction containing ribbon type hyphae similar to zygomycetous fungi. At molecular examination Conidiobolus lamprauges DNA was detected. The clinical, epidemiological, macroscopical, microscopical and molecular aspects characterize conidiobolomycosis caused by Conidiobolus lamprauges in sheep.

Fatal onion (Allium cepa) toxicosis in water buffalo (Bubalus bubalis).

Toxicosis caused by the ingestion of onion (Allium cepa) by 5 water buffalo (Bubalus bubalis) occurred in the district of Caçador, Santa Catarina, Brazil. The water buffalo died after ingestion of a large quantity of onion that had been left in the pasture. Clinical signs started 8 days postingestion and were characterized by pale mucous membranes, lethargy, and dark urine. At necropsy, pieces of onions were found in the rumen of 1 animal. The carcass smelled strongly of onion, and the kidneys and urine were dark brown. Microscopic renal lesions included tubular degeneration and necrosis with deposits of eosinophilic material in the cytoplasm of renal tubular epithelial cells and tubular lumina. These changes were consistent with hemoglobinuric nephrosis. Centrilobular coagulation necrosis was observed in the liver accompanied by hemorrhage and macrophages containing brown cytoplasmic pigment. A diagnosis of hemolytic anemia caused by onion toxicosis was based on the epidemiological data, clinical signs, macroscopic changes, and histological lesions.

Intoxicação espontânea e experimental por nitrato/nitrito em bovinos alimentados com Avena sativa (aveia) e/ou Lolium spp. (azevém)

Epidemiological data, clinical and pathological findings of the spontaneous andexperimental poisoning by nitrate and nitrite in cattle fed oats (Avena sativa) and/or ryegrass (Lolium spp.), diphenylamine test, and the nitrate content in the samples of the pasture where the outbreaks occurred, are described. The disease occurs in different regions of the State of Santa Catarina, in which pastures have exuberant growth, after receiving excessive amounts of chemical and/or organic fertilizer, mainly when raining occurs after a period of dry wheather. The animals grazing these pastures quickly develop brown mucosa, tachypnea, staggering gait, frequent urination, bloating, lateral recumbency and death in few minutes or hours. At necropsy of four animals that died spontaneously, the main lesions found were brown mucosa, dark color of the blood (chocolate), intense red color of the skeletal muscles and of the left part of the myocardium. The experimental reproduction of the disease was performed in seven cattle, with pastures from four farms where the disease occurred. The animals were fed with fresh oats and ryegrass and/or hay of it. Four animals died, two became ill and recovered, and one was treated with 2mg/kg per body weight of methylene blue 1%, and one cattle did not show changes. Clinical signs and lesions of the diseased animals that died were similar to natural cases. Microscopic changes were not observed in spontaneous and experimental poisoning. The diphenylamine test was positive in all the farms where the outbreaks occurred. The chemical analysis performed on samples of the pastures from several farms, in which outbreaks of the disease occurred, ranged from 0.30to 3.36% of nitrate in the dry matter. The disease is associated with the ingestion of oats and/or ryegrass pastures heavily fertilized, which accumulates high levels of nitrate after a period of rain and is characterized by rapid breathing, dark-colored blood, brown mucous and rapid death.