Enzymatic Activities and Antagonistic Interactions of Aspergillus niger, Trichoderma harzianum and Mucor hiemalis Associated with Compressed Rabbit Dung

Rabbit dung is a nutrient-rich coprophilous substrate that supports diverse fungal communities responsible for organic matter decomposition and nutrient cycling in soils. This study aimed to evaluate the production of selected extracellular enzymes (amylase, cellulase, phenol oxidase, urease and protease) by three soil fungi, Aspergillus niger, Trichoderma harzianum and Mucor hiemalis, during decomposition of gamma‑sterilized, compressed rabbit dung, and to assess their mutual antagonistic interactions in dual and triple cultures. Enzyme activities were screened using plate assays on specific media, while antagonism was determined by growth inhibition and changes in dry weight loss of the substrate under different fungal combinations. The results indicated that T. harzianum exhibited the broadest enzymatic profile, producing strong amylase, cellulase, phenol oxidase and urease activities, whereas A. niger showed marked amylase and cellulase activities with limited phenol oxidase and urease, and M. hiemalis displayed restricted activity mainly for phenol oxidase and urease. Antagonism assays revealed that combinations involving T. harzianum and A. niger enhanced dry weight loss and energy depletion compared to single inoculations, while treatments including M. hiemalis tended to reduce overall performance. These findings highlight the functional diversity and competitive behavior of coprophilous fungi and suggest their potential for biotechnological applications in composting and waste valorization