Introduction. The article deals with the results of the mycotoxicological analysis of feed samples of pond fish. There were found the T2-toxin and aflatoxins.The combined presence of aflatoxins B1, B2, G1 and G2 and T2-toxin was found in all samples of fish feed. Was also studied the impact of combination of several mycotoxins on organoleptic and physico-chemical characteristics of fish carcasses. Fish, affected by mycotoxins, can be classified to the category of doubtful freshness.
Materials and methods of research. The studies were conducted between May and October 2019. The investigated materials were a large number of grain and grain mixtures, for feeding fish in six ponds in Nikolaevska settlement community of Sumy region. Preparation of grain samples were made according resolution of the Cabinet of Ministers of Ukraine, June 14, 2002, No. 833 «The order of the selection of samples animal, plant and biotechnological origin». The studies of the toxicity and persistent T2-toxin and full amount of aflatoxins B1, B2, G1 and G2 are conducted on the basis of the Sumy Regional Laboratory of Veterinary Medicine. Feed toxicity was investigated by bioassay on the Tetrahymena piriformis infusorium used the DSTU 3570-97. The RIDASCREEN test systems were used to investigate the aflatoxins B1, B2, G1 and G2 in grains and grain mixtures. Ichthyopathological studies were conducted in the department of Veterinary and Sanitary Examination, Microbiology, Zooghygiene, Safety and the Guality of Livestock Products of the Sumy National Agrarian University by the accepted methods.
Results of research and discussion. In the territory of the Nikolaevska settlement community of Sumy region there are six ponds, in which hold fish, mainly crucian and carp. The fish are fed once a week. Feed mainly consists of grain waste (barley, wheat), which is supplied by local farmers. Food is stored in unsuitable premises. In the feed we noted the presence of remains of substandard grain, which was thrown out during separation. Grain samples are not sampled and laboratory tests are not carried out.
The feed is shipped by transport to ponds, dumped from the shore into a pond, immersed in to the water, where consumed by the fish.
Totaly 19 samples of feed were examined during this period. Organoleptic evaluation of grain and grain mixtures revealed that the color of the grain was natural, the smell of all the samples had a certain tinge of moldy-musty, some samples had signs of fermentation and mold.
Aqueous solutions of the grain extracts and mixtures of the test samples caused a stopping of movement and death of all Tetrahymena piriformis infusions up to 60 minutes in 7 samples, that indicates the toxicity of these feeds. Low toxicity was detected in 11 samples of experimental feed. The absence of toxicity was evidenced by the activity of Tetrahymena piriformis infusoriums, which persisted for 1 hour after the action of aqueous extracts of the samples.
The results of the determination of the toxicity of grain feed using infusorium Tetrahymena piriformis.
To analyze the content of major mycotoxins was used competitive enzyme immunoassay. The RIDASCREEN FAST Aflatoxin test system and the RIDASCREEN FAST T-2 Toxin test system have a high sensitivity of 0.0017 mg / kg and 0.05 mg / kg, respectively, which made it possible to determine the content of T-2 toxin, the amounts of aflatoxins B1, B2, G1 and G2 in their lowest concentration.
The results of analysis of feed samples using the amount of aflatoxins B1, B2, G1 and G2
That in all samples of grain and grain mixtures was established the presence of aflatoxins B1, B2, G1 and G2. In 7 samples its content exceeds the maximum permissible concentrations.
In 10 samples, the combined presence of aflatoxins B1, B2, G1 and G2 and T2-toxin was found, in 5 samples - exceeding the maximum levels. It is known that the combination of several mycotoxins can lead to their synergistic interaction, which will have a more pronounced toxic effect.
Unfortunately, it was not possible to determine the maximum content of aflatoxins B1, B2, G1 and G2 and T2-toxin, so further test kits with different reading ranges should be used, since highly sensitive mycotoxin detection kits make it impossible to determine up to 1 mg / kg.
In the following research, we studied the chemical properties of fish meat: reaction to peroxidase (benzidine sample), amount of amino-ammonia nitrogen, reaction with copper sulfate, reaction with Eber reagent, determination of hydrogen sulfide, pH and reaction with Nesler reagent.
When muscle is damaged by mycotoxin, the products protein breakdown appears, which promotes rapid breakdown of tissue elements and leads to rapid deterioration of fish. Analyzing changes in veterinary-sanitary and physico-chemical parameters of fish affected by mycotoxicosis, we can classify the affected fish in the category of doubtful freshness.
Conclusions and prospects for further research.
During the investigate of grain and grain mix for feeding pond fish it was found that 19 samples were highly toxic and 36.8% were law toxoc.
2. Using the competitive enzyme immunoassay the combined presence of aflatoxins B1, B2, G1 and G2 and T2-toxin was found in all samples
In 7 samples its content exceeds the maximum permissible concentrations. T2-toxin was found was found in 16 samples, and in 10 samples its content exceeds the maximum permissible concentrations.
Fish affected by mycotoxins for organoleptic and physico-chemical characteristics can be classified to the category of doubtful freshness.
Prevalence rate of Helicobacter pylori infection among population of Ryazan region