The protostop drug effectiveness in diarrhea of mixed parasitic-bacterial etiology in calves

In cattle breeding, diseases of the gastrointestinal tract (GIT) of calves with diarrheal syndrome, which are widespread almost everywhere and involve most of the livestock, remain a serious problem. Gastrointestinal diseases of calves of mixed, parasitic-bacterial and parasitic-viral etiology are often noted, a combination of Cryptosporidium spp. with Escherichia coli , enterobacteria of the genus Salmonella , Klebsiella have been detected. Thereof, it is optimal to use broad-spectrum drugs that have antimicrobial and antiprotozoal effects. This article presents for the first time the effect of the drug paromomycin sulfate on pathogens of gastrointestinal diseases of both parasitic and bacterial origin. The minimum inhibitory concentration (MIC) of paromomycin sulfate has been established for pathogens of gastrointestinal tract diseases of calves of bacterial etiology, i.e., Salmonella Dublin, Escherichia coli with hemolytic properties, Klebsiella pneumoniae , Proteus vulgaris , Citrobacer freundii . The aim of study was to examine the therapeutic effectiveness of the drug Protostop (the active substance is paromycin sulfate) for diseases of the gastrointestinal tract with diarrheal syndrome in calves. The research was carried out at a cattle farm (Leningrad Province, Lomonosovsky District) in July-August 2021. The experiments involved calves ( Bos taurus ) of the black-white breed, up to 5 months old, weighing from 30 to 50 kg. Fecal samples weighing 20-40 g were taken from the rectum of calves with clinical signs of gastrointestinal dysfunction. To detect oocysts of Cryptosporidium spp. fecal smears were prepared on a glass slide, and stained using a Diakhim-Kit for Ziehl-Neelsen staining (NPF Abris+, Russia). Microscopy was performed using a Primo Star microscope (Carl Zeizz, Germany). To establish the quantitaty and species of enterobacteria, 10-fold dilutions of feces in saline solution were sown in 0.05 ml quantities on the Endo nutrient medium (LLC Research Center for Pharmacotherapy, Russia). To assess the therapeutic effectiveness of the drug Protostop (powder, 1 g of the drug contains 100 mg of paromomycin sulfate; AVZ Ltd, Russia), animals in whose feces consist oocysts of Cryptosporidium spp., strains of hemolytic E. coli and opportunistis microorganisms were selected. We formed 5 groups of animals of 10 animals in each (4 experimental, 1 control). All calves in experimental groups were given the drug Protostop individually, orally, once a day. Before use, a single dose of the drug was dissolved in water by adding the liquid to the powder. Animals from the 1st group received the drug at a dose of 250 mg/kg of body weight for 3 days, calves from the 2nd group were given the drug at the same dose for 5 days. Animals of the 3rd and 4th groups received Protostop at a dose of 350 mg/kg body weight, respectively, for 3 and 5 days. Calves from the control group were treated with an analog drug Parofor 70 (powder, 1.0 g of the drug contains 100.0 mg of paromomycin sulfate; Biovet AD, Bulgaria). The drug was administered at a dose of 350 mg/kg body weight orally once a day for 5 days. During a clinical examination on the 3rd, 5th, 10th and 14th days from the start of treatment, the health condition of the animals, their consumption of water and feed, the presence of changes in the function of the GIT, the condition of the mucous membranes and coat were examined. Coprological studies for the presence of oocysts of Cryptosporidium spp. were carried out on the 8th and 12th days of treatment, bacteriological on the 10th day after the end of treatment. To assess the health condition, blood samples for examination was taken in all groups. The MIC of paromomycin sulfate, the active substance of the drug Protostop, was determined by the method of serial dilutions according to GOST R ISO 20776-1-2010. Strains for which the MIC of paromomycin did not exceed 4 μg/ml were classified as susceptible, and those above 4 μg/ml were classified as resistant. A parasitological study revealed more than 25 oocysts of Cryptosporidium spp. in the feces of calves in the field of view, which indicated a high intensity of invasion. A bacteriological study revealed Escherichia coli strains with hemolytic activity and other strains of opportunistic microflora. After treatment, all calves in the experimental groups showed significant improvements in their health condition: the animals became more active, diarrhea stopped, and the feces became a mushy consistency, characteristic of cattle feces.