Food allergies in weaned piglets in experiment and spontaneous occurrence
Authors: Matsinovich M. 
Published: July 2019

Gastrointestinal diseases in young animals are recorded quite often, especially in industrial complexes. Diseases of this group can be up to 70-80 % of the entire internal pathology of young animals. Literary data show that in the etiology and pathogenesis of the disease in weaned piglets an allergic reaction to the components of the feed, which significantly complicates its course, may play. The development of nutritional allergies is also favored by the functional insufficiency of the glands of the digestive system of pigs during the first weeks of life, as well as the violation of their functions in various diseases of the gastrointestinal tract, which can lead to incomplete protein breakdown and accumulation of antigenic substances.
The aim of the study was to study the most characteristic symptoms and blood indices during experimental reproduction of food allergies in piglets and spontaneous occurrence under production conditions. Studies were performed in 2 stages. At first, under the conditions of the clinic of the Department of Internal noninfectious Animal Diseases of the Vitebsk State Academy of Veterinary Medicine formed two groups of pigs aged 30–35 days with an average weight of 8–10 kg. In animals of the experimental group, experimental reproduction of feed allergies was carried out by abruptly changing the milk type of feeding to the concentrated one. At the second stage of the research, in the conditions of a pig complex, 200 pigs of 40- to 60-day-old patients with gastroenteritis were examined. Gastroenteritis in experimental animals was non-infectious in nature and was primarily due to the sharp weaning of animals. To detect an allergic reaction, laboratory blood tests were performed using the above methods, and also the clinical manifestations of the disease were taken into account.
The clinical picture of experimental pathology at first was characterized by lethargy, reluctant eating of new food, the pigs periodically showed anxiety, which was followed by apathy. During the first three days of the experiment, intestinal meteorism was observed in piglets, which in 6 animals and 66,7 % was replaced by diarrhea, and in 33.3 % animals it was accompanied by constipation. Body temperature in all porosyat remained within the normal range. On the fourth day of the experiment, one of the animals of the experimental group fell, and according to the results of the autopsy, catarrhal-hemorrhagic were found: pa-strorenteritis, typhlitis and colitis. By the twelfth day, the functions of the gastrointestinal tract were normalized in all animals of the experimental group. In the animals of the control group during clinical observation for this period, no abnormalities were identified.
On the 14th day of the experiment, an intracutaneous test was performed. As an allergen, we used a protein extract from the feed used in the experiment, containing the gliadin, albumin and globulin fractions of the gluten protein. In all the animals of the experimental group, after 6 hours, edema of the skin and hyperemia appeared at the injection site, the skin fold thickness was from 1,5 to 2,5 mm at the injection site of the allergen, compared with 0,5-0,7 mm in injection site phosphate buffer. 24 hours after the injection of the allergen, the intensity of skin hyperemia decreased, but there was a noticeable thickening of the skin fold in the animals of the experimental group, it was 3,6 ± 0,22 mm compared to 0.6 ± 0.04 mm at the injection site of phosphate buffer. Changes in the skin at the injection site disappeared within 24 to 48 hours.
The results of laboratory blood tests indicate the development of an allergic reaction in animals of the experimental group. They were characterized by more pronounced leukocytosis and eosinophilia, as well as a higher concentration of total protein in the blood serum, of immunoglobulins at 14-21 days, i.e. during the period of the greatest severity of the allergic reaction. The most significant and statistically significant in such animals was a more than 2-fold increase in the number of eosinophils and an increase in the concentration of immunoglobulins by 21 %. A significant concentration of circulating immune complexes of the CIC was detected in the blood of the piglets of the experimental group, as evidenced by a lower % of light transmission in a special test – below 95 %.
In the experiment in the conditions of the pig complex, it was found that in 27 % of weaned piglets in the pathogenesis of gastroenteritis, sensibilization of the body develops and the allergic factor affects the duration and severity of the disease. The duration of the disease (with treatment without antihistamine drugs) was 5 –10 days (6,8 ± 0,32 days) with a mortality rate of 4.4 %. More than 30 % of the pigs during the first 7 to 14 days after weaning and recovery observed the recurrence of the disease for no apparent reason.
Thus, an unusual new feed load, in the period of extraction, leads to the depletion of the local protection mechanisms of the gastrointestinal tract in piglets. In the mucous membrane of the small intestine, inflammation develops, which leads to a violation of the secretory, enzymatic, absorbing function of the intestine and metabolic disorder. Against this background, feed antigens come from the intestine into the blood and as a result of their contact with immunocompetent cells, an immune response and body sensitization develops. Experimental and spontaneous feed allergies in weaned piglets are similar in clinical laboratory to laboratory. In terms of production, the weaned piglets of patients with gastroenteritis developed an allergic reaction as a complication of the disease, while the duration of the disease and mortality was almost 2 times greater.
Key words: food allergies, gastroenteritis, piglets, weaning, therapeutic efficacy, circulating immune complexes.