Efficacy of a Bio-hygienization Additive in Controlling the Yeast-like Microalga Prototheca zopfii

In vitro study at the University of Perugia on sterile manure inoculated with Prototheca zopfii: reduction of viable cell concentration up to −99.9% in the treated sample compared to control (P < 0.01 as reported in the contribution), using SOP treatment (SQC 233 formula).

Summary: In vitro trial on sterile manure inoculated with Prototheca zopfii, comparing treated and control samples. The contribution reports a reduction in viable cell concentration in the treated sample of up to −99.9% compared to control (P < 0.01).

Prototheca zopfii is an opportunistic microalga associated with environmental mastitis in dairy cows, often with a chronic course and limited response to interventions, potentially impacting SCC and herd management. Its epidemiology is strongly linked to the environmental reservoir: it can persist in organic-rich matrices (manure, water, moist bedding), increasing animal exposure. Reducing Prototheca load in farm matrices therefore helps decrease environmental infection pressure and supports preventive strategies based on hygiene and bedding management.

In this context, the contribution presented at the National Mastitis Council (NMC) 47th Annual Meeting — a peer-reviewed congress with selection by the scientific committee — describes an in vitro study conducted at the Department of Applied Biology – Microbiology Section, University of Perugia (Prof. P. Buzzini), aimed at evaluating the ability of an SOP additive to reduce viable cell concentration of Prototheca zopfii under controlled conditions.

The experimental setup involved inoculating a growing cell suspension of Prototheca zopfii (pre-selected strains) onto a sample of sterile manure. SOP treatment was applied to the treated sample, while a parallel sample was incubated without treatment (control). The contribution reports repeated addition of the treatment at regular intervals (every 7 days) in the treated sample.

At the end of the trial, the contribution reports that SOP treatment (SQC 233 formula, included in products such as SOP EASYCOW, SOP STAR COW, SOP GOLD PRO COW) reduced the viable cell concentration of Prototheca zopfii in the treated sample compared to control. The control reached 7.5 log₁₀ CFU/ml, while the treated sample decreased to 4.5 log₁₀ CFU/ml, corresponding to a reduction of up to −99.9% compared to control, with statistical significance P < 0.01 as reported in the contribution.

Overall, the study highlights the relevance of controlled in vitro evidence for understanding the potential of bio-hygienization strategies applicable to farm matrices, supporting environmental hygiene programs.