Conversion of Posidonia oceanica wastes into alternative feed for ruminants by treatment with microwaves and exogenous fibrolytic enzymes produced by fermentation of Trichoderma longibrachiatum

Posidonia oceanica wastes is abundant biomass in Mediterranean coasts characterized by a high content of dietary fiber and polyphenolic compounds and pose a serious pollution problem. The aim of this study was to valorize these seagrasses into suitable alternative feed for ruminants through conversion approach with microwaves treatment at a power of 750 W for 240 s and exogenous fibrolytic enzymes (EFE) produced by fermentation of Trichoderma longibrachiatum at a rate of 4 μl/g dry matter for 24 h.

The results showed that microwave treatment improved the amount of rumen fermentation and digestibility of cell wall polysaccharides and dry matter without altering the fermentation rate. The EFE treatments stimulated the rate of rumen fermentation especially in the initial phase and reduced the half-time of fermentation. The effect of EFE became less pronounced with increasing incubation time, as well as did not affect amount of rumen fermentation and digestibility. Only microwave treatment followed by EFE converted some of their cellulose and hemicellulose to reducing sugars. This modification provides a suitable substrate for proliferation of rumen protozoa, accelerates rumen fermentation process, shortens time of onset of rumen fermentation, and increases extent of rumen fermentation. As a result, their digestibility and net energy available for lactation are improved. In addition, this approach stimulates rumen microbiota to produce short-chain fatty acids and to bio-convert rumen ammonia nitrogen to microbial protein. This environmentally friendly process could be used to convert these seagrass wastes into suitable ruminant feeds.