Cumulative properties of Vulpes Optima ZS feed additive with histological assessment of internal organs

This article presents the results of a study of the cumulative effect of new polymer-stabilized feed additive Vulpes Optima ZS on laboratory animals’ experiment. The study was conducted on 30 albino male rats with an average body weight of 220 g in accordance with the principles of Methodological Guidelines MU 1.2.2520-09 and the classic test by R.K. Lim et al. The test drug was administered orally and intragastrically via a gavage in increasing doses: every 4 days, the dose was increased by 1.5 times, starting with a dose equal to 1/10 of the previously established sublethal dose. Daily clinical monitoring was conducted throughout the experiment, recording live weight dynamics, livestock survival, behavioral responses, feed and water consumption, coat condition and the nature of physiological toxicities. At the end of the exposure period, a postmortem analysis and a comprehensive histological examination of the parenchymatous organs (liver, kidneys) and gastrointestinal tract sections (stomach, small intestine) were performed, with sections stained with hematoxylin and eosin. The results indicate no mortality or statistically significant delays in body weight gain in the experimental animals compared to the control. The calculated cumulative coefficient (Kcum = 11.06) allows the additive to be classified as hazard class IV substances with weak cumulative properties. Macroscopic and microscopic images of the internal organs of experimental rats did not significantly differ from those of the control samples. The organ structure was within physiological norms: the architecture of liver lobules and renal nephrons was preserved, as was the integrity of gastrointestinal mucosa. There were no signs of dystrophy, necrosis, inflammatory infiltration or sclerotic changes. The obtained data support the conclusion that Vulpes Optima ZS feed additive has a low cumulative potential and is safe for long-term use in the studied dose range.