Impact of L-phenylalanine supplementation on the performance of three-week-old broilers fed diets containing ochratoxin A. 2. Effects on hematology and clinical chemistry

New Evidences about the Carcinogenic Effects of Ochratoxin A and Possible Prevention by Target Feed Additives

A review of the carcinogenic effects of ochratoxin A (OTA) on various tissues and internal organs in laboratory and farm animals is made. Suggestions are made regarding how to recognize and differentiate the common spontaneous neoplastic changes characteristic for advanced age and the characteristic neoplasia in different tissues and organs in laboratory animals/poultry exposed to OTA. The synergistic effects of OTA together with its natural combination of penicillic acid are also investigated regarding possible carcinogenic effects. The malignancy and the target location of OTA-induced neoplasia is studied. The sex-differences of such neoplasia are investigated in the available literature. The time of appearance of the first neoplasia is investigated in long-term carcinogenic studies with OTA-treated animals. The possibility of target feed additives or herbs to counteract the toxic and carcinogenic effects of OTA is studied in the available literature. Some effective manners of prophylaxis and/or prevention against OTA contamination of feedstuffs/foods or animal production are suggested. The suitability of various laboratory animals to serve as experimental model for humans with regard to OTA-induced tumorigenesis is investigated.

Follow up long term preliminary studies on carcinogenic and toxic effects of ochratoxin A in rats and the putative protection of phenylalanine

Carcinogenic effects of ochratoxin A (OTA) on liver, kidneys, intestine, lung and eyes of Wistar rats exposed to 10 ppm or 5 ppm OTA in the diet and additionally supplemented or not with phenylalanine (PHE) were examined during 24-months experimental period. OTA was seen to provoke strong degenerative changes and slight pericapillary oedema in most internal organs, e.g. kidneys, liver, intestine, spleen and brain. Six of total nine neoplasms were identified as malignant and three as benign. Five of total six malignant neoplasms and two of total three benign neoplasms were seen in male rats. The pathological finding in rats after two weeks feeding with OTA-contaminated feed was dominated by degenerative changes in various internal organs, which were weaker in the group additionally supplemented with PHE. The protective effect of PHE was evident with respect to OTA-induced decrease of serum glucose and serum protein, but this protection was not singnificant with respect to serum enzymes activity. The number of neoplasms in PHE-supplemented group exposed to 10 ppm OTA was similar to that in the group exposed to twice lower feed levels of OTA alone, suggesting about a possible protective effect of PHE. The rats would not be able to serve as experimental model for humans with regard to OTA-induced tumorigenesis, because the target organ of OTA-toxicity in humans and pigs is mainly the kidney as opposed to the significant damages and carcinogenic effects seen in various organs in rats exposed to OTA.

Influence of Saccharomyces cerevisiae to ameliorate adverse effects of ochratoxin on biochemical profile and immune response in broiler chickens

To establish the ochratoxicosis ameliorating efficacy of dietary Saccharomyces cerevisiae (SC), day-old broiler chicks (240) were divided into 6 treatment groups (T1, control (basal diet); T2, T1 + 200 ppb OTA; T3, T1 + 0.05% SC; T4, T1 + 0.1% SC; T5, T2 + 0.05% SC and T6, T2 + 0.1% SC). Each diet was fed to 5 replicated groups of 8 birds each from 1 to 42 days of age. The total serum protein and haemoglobin (Hb) in T2 and T5 were lower than that of control (T1). The serum protein and Hb content in group T6 was higher than that of T2 and statistically similar to that of control. The serum uric acid, creatinine, ALP, SGOT, SGPT and H/L ratio in ochratoxin fed group (T2) was higher than that of T1. The serum uric acid, creatinine, ALP, SGOT, SGPT and H/L ratio in T6 was lower than that of T2 and statistically similar to that of T1. The CMI and HA titre value in ochratoxin fed group (T2) was lower than that of T1. The CMI and HA titre value in T5 and T6 was lower than T1 but higher than T2. It was concluded that ochratoxin contamination at 200 ppb level in broiler diet altered the biochemical parameters and immune response. Inclusion of Saccharomyces cerevisiae at 0.1% level to the ochratoxin contaminated diet ameliorated the adverse effects of ochratoxicosis on biochemical parameters and immune response of broiler chickens.

Associated efficiency of Saccharomyces cerevisiae and vitamin E in ameliorating adverse effects of ochratoxin A on biochemical profile and immune response in broiler chickens

The associated efficacy of Saccharomyces cerevisiae and vitamin E, in ameliorating ochratoxicosis was investigated in broiler chickens. Day-old broiler chicks (320) were divided into 8 treatment groups, viz. T1 (control; basal diet); T2 (T1 + 150 ppb OTA); T3 (T2 + 0.05% SC + 100 mg vitamin E-VE); T4 (T2 + 0.075% SC + 100 mg VE); T5 (T2 + 0.1% SC + 100 mg VE); T6 (T2 + 0.05% SC + 200 mg VE); T7 (T2 + 0.075% SC + 200 mg VE) and T8 (T2 + 0.1% SC + 200 mg VE/kg diet). Each diet was fed to 5 replicated groups of 8 birds from 0–42 days of age. The total serum protein, cholesterol and haemoglobin content of control group (T1) was higher than that of ochratoxin fed group (T2). The serum protein, cholesterol and haemoglobin value in groups T5, T7 and T8 was higher than T2 but statistically similar to that of control. The serum uric acid, creatinine, ALP, SGOT, SGPT and H/L ratio value in T1 was lower than that of T2. The uric acid, creatinine, ALP, SGOT, SGPT and H/L ratio value in T5, T7 and T8 was lower than T2 and statistically similar to that of control. The CMI and HA titre value of T1 was higher than that of T2. The CMI and HA titre value in T5, T7 and T8 was higher than that of T2 but statistically similar to that of control. It can be concluded that ochratoxin contamination at the rate of 150 ppb in the feed resulted in decreased total serum protein, cholesterol and haemoglobin content and increased serum uric acid, creatinine, ALP, SGOT, SGPT and H/L ratio value. Inclusion of Saccharomyces cerevisiae at 0.1% level along with 100 mg vitamin E or Saccharomyces cerevisiae at 0.075% level along with 200 mg vitamin E/kg diet to the ochratoxin (150 ppb) contaminated feed ameliorated the adverse effects of ochratoxicosis on biochemical profile and immune response in broiler chickens.

Studies on carcinogenic and toxic effects of ochratoxin A in chicks

Carcinogenic/toxic effects of ochratoxin A (OTA) in various internal organs of Plymouth Rock chicks were determined. The number of OTA-induced neoplasms was similar in chicks given 25 ppm L-β-phenylalanine (PHE) in addition to 5 ppm OTA compared to chicks given only 5 ppm OTA, which showed that PHE cannot be used as a real protector against the carcinogenic or toxic effects of OTA in chicks. OTA was found to provoke strong degenerative changes in liver and kidneys, degenerative changes and depletion of cells in lymphoid organs, oedematous and degenerative changes in the brain, muscular haemorrhages and fatty changes in the bone marrow. The target organs for carcinogenic effect of OTA in chicks were found to be kidneys and liver.

Studies on some feed additives and materials giving partial protection against the suppressive effect of ochratoxin A on egg production of laying hens

The protective effects of various feed supplements against the harmful effect of ochratoxin A on egg production and sexual maturation of two-weeks old Plymouth Rock female chicks designed for laying hens were studied. A significant protective effect of the feed additives or materials: water extract of artichoke (WEA), sesame seed (SS), Roxazyme-G (RG) and l-beta phenylalanine (PHE) against the suppressive effect of ochratoxin A (OTA) on egg production of laying hens was found. A similar protection was also seen on the toxic effect of OTA on various internal organs of the same hens. A significant protection was found against the decrease of the weight or the quantity of eggs as well as against the delay of the beginning of the laying period of chicks, both of which were provoked by ochratoxin A. These protective effects were strongest in chicks treated with SS or WEA, but were slightest in chicks treated with l-beta PHE.

Complex etiology, prophylaxis and hygiene control in mycotoxic nephropathies in farm animals and humans

Various etiological factors contributing to the development of mycotoxic nephropathy in farm animals and humans are reviewed. The possible synergistic effect between ochratoxin A (OTA) and other mycotoxins, as penicillic acid (PA) and fumonisin B(1) (FB(1)), contributing to this nephropathy is also considered and discussed. The most convenient ways of prophylaxis and various preventive measures against OTA contamination of feeds or foods are reviewed. A reference is made concerning the most successful methods of veterinary hygiene control in the slaughterhouses in order to prevent the entering of OTA in commercial channels with a view to human health. The economic efficacy of these prophylactic procedures is also considered. An evaluation of human exposure to OTA is made.

Studies on some feed additives giving partial protection against ochratoxin A toxicity in chicks

Significant protective effects of the feed additives: water extract of artichoke, sesame seed, Roxazyme-G and L-beta phenylalanine against the growth inhibitory effect of ochratoxin A (OTA) and associated pathomorphological changes were seen. Similarly, there was less OTA-induced decrease in serum total protein and increase of serum creatinine and urea in the chicks. Whereas OTA induced strong degenerative changes and an increase in weight of kidneys and liver as well as a decrease of the weight of lymphoid organs the additives variously gave protection against these changes. The protection of Roxazyme-G and sesame seed was better expressed in kidneys and liver, whereas the phenylalanine better protected the weight changes in gizzard, heart and the changes in differential WBC count. Notably, sesame seed gave strong protection against 5 ppm OTA-induced suppression of humoral immune response, for which artichoke also had some beneficial effect, whereas phenylalanine had hardly any effect.

Influence of vitamins E and C on the toxic effects of ochratoxin A and T-2 toxin in chicks

The objective of this study was to determine whether two antioxidant vitamins, vitamins E and C, were able to counteract the production of lipid peroxides and the corresponding toxic signs of two important but diverse mycotoxins, T-2 toxin and ochratoxin A (OA). Experiment 1 was designed in a 3 x 3 factorial arrangement using three doses of vitamin E (dl-alpha-tocopheryl acetate) in the diet of Leghorn cockerels (required level according to NRC, 10x, and 100x requirements) and three toxin treatment [no toxin (Diets 1, 2, and 3), 4 mg T-2/kg of diet (Diets 4, 5, and 6), and 2.5 mg OA/kg of diet (Diets 7, 8, and 9)]. The experimental design for Experiment 2 was the same as for Experiment 1 except that Vitamin C (0, 200, and 1,000 mg/kg of diet) was used in place of vitamin E and the concentration of T-2 in Diets 4, 5, and 6 was increased to 5 mg/kg of diet. Six replicates were used per treatment with four birds per replicate. In both experiments, OA and T-2 decreased the performance of the chicks significantly. The concentration of uric acid in the plasma increased (P < 0.001) when OA was added to the diet, whereas the supplementation of the diet with vitamin E (100x the requirement) partially counteracted this effect (P = 0.07). The presence of T-2, and especially OA, in the diet decreased the concentration of alpha-tocopherol in the liver (P < 0.001). Consistent with these findings were increased values of malondialdehyde (MDA) in the liver due to OA. In Experiment 1, vitamin E supplementation partially ameliorated the prooxidative effects of OA by decreasing the concentrations of MDA (P < 0.05). These data suggest that lipid peroxides are formed in vivo by T-2 and especially by OA and that these effects can be partially counteracted by an antioxidant such as vitamin E but not by vitamin C.