SURVIVAL OF PROBIOTIC LACTOBACILLI IN THE COMPOSITION OF GRANULAR FEED DURING ITS LONG-TERM STORAGE

Abstract

Bacteria of the genus Lactobacillus are a promising group of microorganisms that can be used as probiotics in aquaculture. An effective method of targeted delivery of these bacteria to the body of aquatic organisms, especially in large farms, is the addition of probiotic preparations directly to the feed. However, there is a problem of long-term storage of feed with added probiotics. In this study, the survival of probiotic microorganisms of the genus Lactobacillus in the composition of granular feed during its long-term storage was evaluated. The probiotic strains of lactobacilli Lactobacillus casei IMV B-7280, L. delbrueckii subsp. bulgaricus IMV B-7281 and L. acidophilus IMV B-7279, kindly provided by the D.K. Zabolotny Institute of Microbiology and Virology of the National Academy of Sciences of Ukraine, were added to Aller Aqua Bronze feed samples, followed by pelletizing and drying and storage for 28 days. A gradual decrease in the number of probiotic microorganisms in all the studied feed samples during the experiment was found. Two weeks after the beginning of the study, the number of live cells of L. casei and L. bulgaricus did not differ statistically from each other and amounted to about 60% of the initial number of cells. In contrast, the number of viable L. acidophilus cells was 52%. The highest survival rate in the granular feed on the 28th day of its storage was observed for probiotic microorganisms L. delbrueckii subsp. bulgaricus IMV V-7281, which constituted 58% of the initial number of introduced bacteria. The lowest survival rate among the studied lactobacillus strains was observed for L. acidophilus. The optimal shelf life of granular feed enriched with probiotics is 14 days from the date of manufacture.