Aflatoxicosis and Intrinsic Coagulation function in broiler chickens

Comparative Response of the Hepatic Transcriptomes of Domesticated and Wild Turkey to Aflatoxin B₁

The food-borne mycotoxin aflatoxin B₁ (AFB₁) poses a significant risk to poultry, which are highly susceptible to its hepatotoxic effects. Domesticated turkeys (Meleagris gallopavo) are especially sensitive, whereas wild turkeys (M. g. silvestris) are more resistant. AFB₁ toxicity entails bioactivation by hepatic cytochrome P450s to the electrophilic exo-AFB₁-8,9-epoxide (AFBO). Domesticated turkeys lack functional hepatic GST-mediated detoxification of AFBO, and this is largely responsible for the differences in resistance between turkey types. This study was designed to characterize transcriptional changes induced in turkey livers by AFB₁, and to contrast the response of domesticated (susceptible) and wild (more resistant) birds. Gene expression responses to AFB₁ were examined using RNA-sequencing. Statistically significant differences in gene expression were observed among treatment groups and between turkey types. Expression analysis identified 4621 genes with significant differential expression (DE) in AFB₁-treated birds compared to controls. Characterization of DE transcripts revealed genes dis-regulated in response to toxic insult with significant association of Phase I and Phase II genes and others important in cellular regulation, modulation of apoptosis, and inflammatory responses. Constitutive expression of GSTA3 was significantly higher in wild birds and was significantly higher in AFB₁-treated birds when compared to controls for both genetic groups. This pattern was also observed by qRT-PCR in other wild and domesticated turkey strains. Results of this study emphasize the differential response of these genetically distinct birds, and identify genes and pathways that are differentially altered in aflatoxicosis.

Haematotoxicity of trichothecenes

Human toxicosis induced by consumption of foodstuffs contaminated with trichothecenes presents one common major symptom: a haematological perturbation manifesting principally as thrombocytopenia and leukopenia. The patients have rapidly progressing coagulation problems, and compromised resistance to infections. Consequently, they are subject to septicaemia and massive haemorrhages. In horses, cattle, poultry, cats, mice and guinea pigs, subacute and subchronic ingestion of trichothecenes causes a decrease of circulating blood cells frequently associated with bone marrow failure. The origins of haematological effects observed in Fusarium toxin intoxications have been elucidated using in vitro tests. Haematopoietic progenitors are the main target of trichothecenes. Deoxynivalenol (DON) is the least myelotoxic and T-2 the most. As circulating blood cells present a less important sensitivity to these toxins, haematological troubles observed in toxicosis are due to myelotoxicity of these toxins.

Effect of raising dietary protein, amino acids and/or energy levels as an attempt to alleviate severity of the chronic aflatoxicosis by broiler chicks. 1. Performance and toxicity symptoms

In an attempt to alleviate the aflatoxicosis symptoms by broiler chicks fed on low (50 ppb) aflatoxin-contaminated diet; the dietary nutrients were elevated by 2.6% for protein, 0.54 MJ ME/kg for energy or 0.5% for each of methionine and lysine. These supplements were mixed altogether and applied as well. All the experimental diets were offered for a 6-week period followed by a 2-week period on aflatoxin--free diet without supplements as a withdrawal period. It was proved after the treatment period that the raising of energy concentration was beneficial to overcome the aflatoxin effects on the body weight, feed conversion rate, and dressing (eviscerated weight) percentage and stability of relative weights of liver and kidneys. Additionally, the supplements' mixture improved the body weight and the relative weight of the liver comparing with the chicks fed on the aflatoxin diet without additives. All of the contaminated diets, except that of the high energy, caused apparently toxic symptoms besides the internal gross pathology. The high energy diet reflected the lowest mortality rate, whereas the highest was with the amino acids supplemented one. The withdrawal period resulted in lower differences among treatments in the body weight. It improved also the dressing percentage (significantly) and to some extent the results of the post-mortem examination.

Effect of low level of dietary aflatoxins on baladi rabbits

Aflatoxins B1, B2, G1 & G2 were administered in a low concentration (100 ppb of each aflatoxin (AN] in a mash offered to Baladi rabbits. An other group of rabbits were fed on the same contaminated mash in addition to 0.25% charcoal (CC). The two groups were compared to control animals fed on AN-free mash. Inclusion of AN in the diet decreased feed and water consumption, body weight and survival rate. Charcoal improved somewhat feed and water consumption and growth rate than AN-group. However, CC-group affected digestibility of organic matter more than AN-group. Relative weights of liver, kidneys, heart and adrenal glands were significantly higher in AN and CC groups than the control group. Blood haemoglobin content, packed cell volume percentage and sedimentation rate were lower in AN group. Although there were an increase in each of serum, calcium, inorganic phosphorus, cholesterol, phospholipids and glutamic-pyruvic transaminase in AN group, yet the serum nitrogen and glutamic-oxalacetic transaminase were reduced. Charcoal had alleviated AN-effects concerning N, GPT and phospholipids. Chemical analysis revealed elevation of water, ash and silica contents of liver and water content of muscles from AN-animals. On the other hand, fat content, GOT and vitamin A in the liver as well as muscles ash were reduced. Addition of CC to the diet reduced AN-effects on liver fat, ash and silica but resulted in a rise of the water content of liver and muscles and liver GPT activity. Charcoal also resulted in a sharp decrease in vitamin A content of the liver. Aflatoxin treatments (in AN and CC groups) reduced bone ash, silica and magnesium as well as bone volume. Charcoal administration increased Ca-content of bones. Aflatoxin feeding (in AN group) resulted in a high residual percentage of AN in muscles, serum, liver, heart and kidneys with relationships of 51 :24 : 3 :2 : 1, respectively. Only 1.42% of the fed AN was excreted in the faeces. Charcoal usage had a good effect as it prevented AN to accumulate in the organs. Aflatoxin contaminated diets (in AN and CC groups) resulted in paralysis, disorder of fat deposition, discolouration and haemorrhages of some organs. Scanning electron microscopic examination revealed no ill effect on the surface structure of the small intestine due to either AN or AN + CC. Pathological examination showed that the main affected organs were liver, heart and spleen, respectively. The changes include hepatic round cell infiltration, irregularities of lobular plats, focal necrosis and periportal fibrosis.(ABSTRACT TRUNCATED AT 400 WORDS)

Induced aflatoxicosis in rabbits: blood coagulation defects

The effect of acute and subchronic experimental aflatoxicosis on blood clotting activity and platelets was evaluated. Male New Zealand White rabbits (weighing 2.4-3.2 kg each) were used. In Experiment 1, 19 rabbits were given orally 0.05 mg of aflatoxin B1 (AFB1)/kg of body weight daily from Day 0 through Day 23. Blood samples were collected before dosing and on Days 2, 5, 9, 12, 16, 19, and 23 of the experimental period. In Experiment 2, 40 rabbits were given a single dose of 0.4 mg of AFB1/kg of body weight. Blood samples were collected before dosing and at 12, 24, 36, and 48 hr after dosing. When compared to baseline and control animal values, one-stage prothrombin times and activated partial thromboplastin times of aflatoxin-dosed rabbits were lengthened, and there was a statistically significant decrease in fibrinogen, Factor IX, VIII, and V activities. Platelet counts were significantly increased in subacutely exposed rabbits, and platelet size was decreased in single high-dose treated groups. Factor deficiencies were attributed to a combination of decreased factor synthesis from hepatic insufficiency and consumptive coagulopathy or primary fibrinolysis.

Biochemical and physiological responses of growing chickens and ducklings to dietary aflatoxins

Two-week-old ducks and chickens were fed for a 14-day period diets containing either groundnut meal (GNM) or fish meal (FM) contaminated with the following aflatoxin (AF) levels: 0, 50, 100, 200 and 400 micrograms AF B1 equivalent per kg ration; nitrogen and energy balances were measured, liver lesions assessed, and various biochemical analyses in blood, livers and muscles were made. Both ducks and chickens fed diets containing GNM were more affected by dietary AF than those fed diets with FM. In ducks, in addition to the reduction in growth and utilization of protein, dietary AF caused liver damage and significantly affected most of the blood constituents; chickens were either not affected or affected to a lesser degree, but no liver damage was recorded. Individual blood tests or enzyme ratios did not provide a sufficiently precise diagnosis of aflatoxicosis. However, blood clotting time and De Riti's ratio, when used in a multivariate regression. allowed projection of a degree of liver damage caused by AF in ducks fed GNM diet with 83.6% of variance being accounted for.

Individual and combined effects of aflatoxin and ochratoxin A on bruising in broiler chickens

A 2 x 2 factorial design with treatments of 0 and 2.5 microgram/g aflatoxin and 0 and 2.0 microgram/g ochratoxin A was used to evaluate the individual and combined effects of these mycotoxins on bruising and blood thigh syndrome in broiler chickens. Trial 1 consisted of four replicate pens of 10 broilers per replicate, which were maintained on these dietary treatments from 0 to 3 weeks of age. At 3 weeks of age two replicate pens per treatment were randomly selected and placed on toxin-free feed with two replicate pens remaining on toxin feed until they were 6 weeks of age when the trial was concluded. In Trial 2 three replicate pens of 38 broilers per treatment were maintained on toxin feed from 0 to 3 weeks of age. At 3 weeks of age 13 broilers per replicate were placed on toxin-free feed with 25 broilers per replicate remaining on toxin until they reached 7 weeks of age when Trial 2 was concluded. These data indicate that a synergistic toxicity exists between aflatoxin and ochratoxin A to significantly (P less than .05) decrease body weight. Body weights of broilers on aflatoxin or ochratoxin A diets for only 3 weeks partially recovered by 6 or 7 weeks of age; however, the body weights of broilers on the interaction treatments for only 3 weeks remained significantly (P less than .05) depressed at 6 and 7 weeks of age.(ABSTRACT TRUNCATED AT 250 WORDS)