With mushroom farming thriving across the Bicol region, researchers from Partido State University (ParSU) are now exploring an innovative way to turn mushroom farming waste, known as spent mushroom substrate (SMS), into fish feed for tilapia aquaculture.
SMS is the leftover material used after mushrooms have been harvested. This organic mix, usually made from crop residues and fungal mycelia or the vegetative structures of fungi, is typically considered as agricultural waste. However, with the booming mushroom industry producing large amounts of SMS, researchers are looking into its potential as a sustainable and cost-effective fish feed ingredient.
Oyster mushroom production has grown rapidly and has become popular among local growers due to their high yield and ability to thrive in Bicol’s warm and humid climate. Compared to other farming ventures, mushroom cultivation requires lower capital, making it an attractive livelihood option for small-scale farmers.
On the other hand, aquaculture, especially tilapia farming, faces rising costs of fish feed, which is one of its most expensive inputs. Traditionally, fish feeds are made using fishmeal or plant-based ingredients like soybean meal. However, the cost and environmental concerns tied to these ingredients have prompted a search for more sustainable alternatives.
The development of a more sustainable option for fish feed is being explored by the project, “SMS in Aquafeeds: Development of an alternative aquafeed ingredient using spent mushroom substrate (SMS).” The project is being funded by the Philippine Council for Agriculture, Aquatic and Natural Resources Research and Development of the Department of Science and Technology (DOST-PCAARRD). Now on its second year, the project led by Ms. Liezel D.C. Atole-Nieva generally aims to formulate and produce an effective aquafeed in tilapia aquaculture using locally derived ingredient, which is the SMS.
The project team collected two types of SMS, freshly harvested and aged from local mushroom farms to determine which version is more suitable for feed use. These samples were then analyzed at the University of the Philippines Los Baños (UPLB) to assess their nutrient composition, including protein, fiber, fat, and moisture content.
The analysis also identified 12 types of beneficial bacteria from the Bacillus family living in the SMS. These microbes are known for their ability to survive in tough environments and even improve gut health in animals, making them a promising addition as aquafeeds.
Five types of fish feeds were developed, each with varying amounts of SMS replacing soybean meal. The experimental feeds were evaluated for key qualities such as durability in water, safety from harmful bacteria, nutritional value, and how well fish accepted them.
Results from the project showed significant differences in their proximate compositions, microbial loads, and functional characteristics, each influencing their suitability for different applications. But generally, aged SMS was found to be more suitable as an aquafeed ingredient as it has higher protein and fiber levels, lower fat and moisture, and showed better stability, making it a good option for feed formulation.
The project is not only helping researchers explore valuable options for agricultural waste but also aims to raise awareness among local fish farmers. By repurposing SMS, the initiative supports a circular economy, turning what was once discarded into a useful resource while also reducing the cost of aquafeeds.
In the long run, the project seeks to achieve improved tilapia production, less waste from mushroom farms, and more affordable fish farming across the region.