A total number of 300 samples of finished commercial poultry feeds, obtained from poultry feed mills (75) samples, wholesale poultry feed dealers (70 samples) and poultry farms (155 samples) were examined for aflatoxin contamination. It was found that 126 (42%) samples. Including 18 (24%) from mills, 19 (27. 1%) from dealers and 89 (57, 42%) from farms were contaminated with aflatoxin. Extraction of aflatoxin from feed samples was carried out both by the aqueous acetone method, and the chloroform extraction method. The extracts were qualitatively examined by quick screening method, minicolumn chromatography method and thin layer chromatograms method. All of the three methods gave comparable results.
The quantity of aflatoxin in contaminated samples ranged from 20 microgram/kg to 2000 microgram/kg. The levels of aflatoxin in majority of the contaminated samples (90.5%) ranged from 20 microgram/kg to 150 microgram/kg feed and only 9.5%) of samples contained higher levels of aflatoxin. Most of the samples containing higher levels of aflatoxin came from commercial poultry farms. These farms had complaints of high mortalities and poor performance in broilers and low production and low mortalities in breeder flocks.
The experimental production of aflatoxin was carried out on long grain rice using a toxigenic strain of Aspergillus Parasiticus (FRR-2752). The rice cultures were incubated at 28 degree centigrade in an atmosphere of high humidity, in the present study a maximum yield of 803 microgram aflatoxin/g rice was obtained.
The determination of LD50 of aflatoxin was carried out in 210 one day old Hy-broiler chicks with an average weight of 38 gram each. The chicks divided into 21 groups labeled from 1 to 21 with 10 birds in each. A single dose of aflatoxin, ranging from 32.82 mg/kg body weight to 0.33 mg/kg body weight, was inoculated into the crops of chicks in groups I to 19, the group 20 acted as solvent control and the group 21 as aflatoxin free control. The birds were observed for 7 days post inoculation. The physical state and mortalities were recorded. The birds which had received higher level of aflatoxin died within few hours of inculcation showing symptoms and lesions of per acute aflatoxicosis.
The LD50 was calculated by abbotâ€™s probit method and was found to be 9.278 mg/kg body weigh.
The pathological effect of a single dose of aflatoxin B1 on the immunocompetent organs was studied in a group of broiler chickens. Day-old 60 hy-bred broiler chicks were raised on aflatoxin tree for 3 weeks and then divided into six groups labeled 1 to 6 with 10 birds in each. A single dose of pure aflatoxin B1 at dose rates of 8, 16, 26, 50 and 100 microgram/birds was given to the birds in groups of 1 to 5 respectively, the sixth group acted as toxin free control, the birds were maintained on aflatoxin free and water ad lib and observed for 3 weeks post inoculation.
The buras of fabric us, thymus and spieen of each bird was removed and histological examined. No appreciable histological changes were seen in the organs of ***ds which had received 8, 16 and 26 microgram aflatoxin while reductions in size accompanied with other degenerative changes were seen in the thymus glands, burin and spleens of birds. This had been injected 50 and 100 microgram aflatoxin respectively. The normal tissues of these were replaced by the inflammatory and fibrous tissues. No changes, gross pathological or histological, were seen in the thymus glands, ***** and spleen of control group birds.
The immunodulatory effects of a single dose of 100 microgram aflatoxin microgram aflatoxin B1/bird on the development of immunity against Newcastle disease Virus vaccine was studied in broiler and layer chickens. A group of 120 one day-old Hy-bred broiler chicks were divided into two groups with 60 birds in each and raised for 3 weeks were on an aflatoxin free feed. Three randomly selected chicks were bled on the first, 7th , 14th and 21st days of age for the determination of maternal haemagglutinin inhibiting (H1) antibody titers. At 3 weeks of age the broilers of each batch were further subdivided into groups labeled as T, T1, T2, k1 and k2 with to birds in each.
A batch of layer chicks was raised for 8 weeks on aflatoxin free feed and then divided into groups T, T1, T2, k1 and k2 with 10 birds in each. Three randomly selected chicks were bled on day one and thereafter weekly for determination of maternal H1 antibody titers till the 7th week of age.
The birds in groups T received vaccine and aflatoxin simultaneously, the birds in groups T1 received vaccine 72 hours before toxin and the birds in groups T2 received toxin followed 72 hours later by vaccine. The birds in group k1 acted as toxin free unvaccinated control. The birds were a maintained on aflatoxin free feed for further 4 weeks. Three randomly selected birds of each group were bled weekly for the determination of serum H1 antibody titers. At the end of 3rd week post inoculation one batch of broilers and the layer groups were challenged with a virulent strain of Newcastle disease virus while the other batch of broilers was given a booster dose of vaccine.
All of the birds in unvaccinated aflatoxin free control groups (k2) died within 72 hours of challenge, while the rest of the birds survived. The survivors were bled and sacrificed one week after challenge/booster vaccination. The sera of birds were examined for H1 antibody titers. The results that the administration of aflatoxin along with, immediately before or after vaccination depressed the development of H1 antibodies significantly.
Immunomodulation caused by continued feeding of aflatoxin on the development of immunity against Pasteur Ella multocide vaccine were studied in layer and broiler chickens. Seventy two one-day old hyline layer chicks were raised for 6 weeks on aflatoxin feed and then divided into groups T, T1, T2, T3, k1 and k2 with 12 birds in the. Seventy two Hy-bred broiler chicks, one-day old were divided into 6 groups T, T1, T2, T3, k1 and k2 with 12 birds in each. A toxin feed containing 2.1 microgram of aflatoxin/gram was prepared. The birds in groups T were given toxin feed for 42 days before and 21 days after vaccination). The birds in groups T1 were fed toxin meal for 21 days before vaccination and those in groups T2 were fed toxin meal for 21 days after vaccination. The birds in groups T3 received a single dose of 9.278 mg Aflatoxin/kg body weight on the day of vaccination. The birds in groups k1 acted as toxin free vaccine control and the birds in groups k2 as toxin free vaccine free control. All of the birds, except those in the groups k2, were vaccination with pasteurella multocida vaccine at the end of 3rd week of age in the broilers and 9th week of age in the layers and challenged with a virulent pastiurella multocida organisms 3 weeks post vaccination. After challenge the birds were shifted to aflatoxin free till the termination of the experiment.
In layers one birds each of group T and T3 died. In unvaccinated toxin free control group of layers as well as broilers (k2) 11 out of 12 birds died. Six broilers of group T and 5 broilers of group T3 died after challenge. The experiment was terminated on the 7th post challenge. The surviors were bled and sacrificed. Serum was collected from 4 randomly selected birds on the day of vaccination and thereafter weekly till the antibody titer were determined by 1HA tests. Continued feeding of aflatoxin depressed the development of hum oral immunity against pasteurella multocida vaccine, the depression being more pronounced in broilers.
The pathological effects of aflatoxin were studied in 3 weeks old broiler chicks. A batch of 36 one day-old broiler chicks was raised on aflatoxin free feed for 3 weeks. On 21 days of age the chicks were divided into groups T, T1 and c with 12 birds in each. A single dose 9.278 mg/kg body weight was injected into the crop of birds in group T. the birds in group T1 were maintained on a feed containing 9.278 mg aflatoxin/birds (2.1 up/g feed) for 4 weeks. The third group Â® acted as control. The experiment was terminated on the 49th day of by sacrificing the survivors.
The livers of birds in group T1 were enlarged, and the heart was atrophied. Regenerative changes, some bile duct hyperplasia and fatty changes were seen in liver of birds in group T. in birds of group T2 the liver was enlarged and showed nodular hyperplasia. Histological the liver tissue showed acute necrosis, perihelia fibrosis, nuclear dissolution, bile duct proliferation and lymphoid hyperplasia changes were also seen in the heart kidneys and other organs. No gross or histological changes were present in the organs of the control group (k) birds.
The effects of aflatoxin on the live weight, dressed weight, the weight of liver, heart and gizzard, some seral enzymes. And bilirubin was studied in a group of 165 broiler chicks. Day old Hy bred broiler chicks were raised on aflatoxin free feed for 3 weeks and then divided into 3 groups T, T1 and k with 55 birds in each. The birds in group T received a single dose of 9.278 aflatoxin/kg body weight while the birds in the groups T1 received 9.278 mg aflatoxin/birds which was mixed in feed and offered ad. Lib. To these birds over the next 4 weeks. The birds in group k acted as the toxin free control. The experiment was terminated on the 28th day post inoculation by sacrificing the survivors. Five chicks from each group were bled through cardiac puncture and sacrificed, daily from day one (21st ) day age to the 7th day post inoculation (28th day age) and thereafter weekly till the end of the experiment. Serum of these birds was examined for SGOT, SGPT, LDH, sap and bilirubin.
Continued feeding of aflatoxin or administration of a single dose of aflatoxin significantly depressed the live weight dressed weight and weight of heart, while it significantly increased the weight of liver and gizzard. Administration of a single dose of aflatoxin produced dramatic increase in the volume activity of SGOT, SGPT, LDH, SAP bilirubin within 24 hours of toxin administration, the values remained higher during the first week and thereafter slowly come down. In birds fed on contaminated meals the enzyme activity and bilirubin gradually increased during the first week and remained high till the termination of the experiment. In the birds of control group the activity of these parameters remained on baseline levels.
No carcinogenicity was seen in any of the internal organs of layer chickens which had been raised for year on feed containing 2 ug aflatoxin/g.
No aflatoxin or aflatoxin residue could be detected in the liver, kidneys and breast muscles of broilers, which had been fed contaminated meals for various lengths of time, and were shifted to aflatoxin free 7 days before slaughter. Aflatoxin was recovered from the liver and kidneys of layers which were feeding a contaminated meal at the time of sacrifice, the rate of recovery being I microgram/100 gram liver tissues and less than 1 microgram/100 gram kidney tissue. No aflatoxin could be detected in the breast muscles of these chickens