THE SEARCH FOR SOURCES OF ENTEROBACTERIA AND CLOSTRIDIA ENDOTOXINS IN RUSSIAN DAIRY FARMS: POSSIBLE TRANSFER OF ENDOTOXINS THROUGH THE FEED–COW–MILK CHAIN

Abstract

The prevention of infectious diseases in dairy cattle is important for both economic efficiency of livestock production and public health. Here, samples to identify bacterial endotoxins were collected from two commercial dairy farms in Leningrad Oblast in 2023: farm A in the Pushkin District (samples of feces and milk were taken) and farm B in the Gatchina District (where samples were taken from the feed-ing table, milk and rumen chyme. The study comprised four groups (A1, A2, B1, B2) where 1 was the control and 2 the test group. A1 were healthy, A2 showed signs of pathologies of the limb joints, B1 received the basic diet (BD) and B2 were fed this, plus the feed ad-ditive AntiKlos (BIOTROF LLC), which has a high level of antago-nistic activity against clostridia and enterobacteria). Using PCR, samples were examined for the presence of genes for Shiga toxins (stx1A, stx2B), intimin (eae) and enterohemolysin (ehxA) produced by enterobacteria; for alpha (cpa1), beta (cpb) and epsilon toxin (etx) produced by Clostridium perfringens, plus binary toxin (cdtB), toxin A (tcdA) and toxin B (tcdB) produced by Clostridium difficile. In the test Group A2, one animal out of six studied (16.7%) had the intimin (eae) and enterohemolysin (ehxA) genes produced by enterobacteria that were not found in the control A1. The epsilon toxin gene (etx) was the most common and present in 100% of the examined fecal samples from both farms and 100% of milk samples from farm A. Our studies demonstrate the possibility of transfer of some endotoxins of enterobacteria and clostridia through the feed–cow–milk chain that depends on the specific live-stock production conditions.