K. Burlakova
Department of Animal Husbandry – Non-ruminants and Special Industries, Faculty of Agriculture, Trakia University, 6000 Stara Zagora, Bulgaria

(Manuscript received 29 January 2026; accepted for publication 25 February 2026)

*e-mail: katerina.burlakova@trakia-uni.bg

Abstract. This study evaluated the effect of dietary sodium butyrate (SB) supplementation on the pH dynamics of liquid manure produced by fattening pigs during storage under controlled temperature conditions. Two experimental groups were formed: a control group fed a basal diet and an experimental group receiving the basal diet supplemented with a microencapsulated sodium butyrate-based additive (30% active compound; 1.0 kg/t feed). The feeding trial covered the entire fattening period (70 days; from 90 to 160 days of age). Manure samples were collected from slurry channels at different stages of the fattening period and subsequently stored at 5, 10, 15, 20, and 25°C. The pH values were recorded on days 1, 3, 5, and 7 of storage. In vivo monitoring revealed that dietary SB supplementation resulted in a statistically significant reduction in fresh slurry pH from week 3 until the end of the fattening period (P≤0.05). During storage, the acidifying effect was maintained for a longer duration at lower temperatures (5-15°C), whereas at higher temperatures (20-25°C) a more rapid pH rebound was observed, indicating accelerated biochemical transformations. The findings demonstrate that sodium butyrate exerts an indirect acidifying effect on pig liquid manure, with temperature influencing the persistence of this effect during storage. These results suggest that SB supplementation has the potential to influence nitrogen transformation processes and contributes to environmentally sustainable pig production systems.