Effect of Agro-Industrial by Products Derived from Volatile Fatty Acids on Ruminant Feed In Vitro Digestibility.

Simple Summary: The problem of food and agricultural waste, known as agro-food byproducts (AFB), is growing, and researchers are trying to find ways to turn this waste into something useful. One promising solution is acidogenic fermentation, a process that converts AFB into volatile fatty acids (VFAs) that can potentially be added to animal feed, providing energy and reducing reliance on traditional feed components like silage and concentrate. The main goal of this study was to determine if adding VFAs to ruminant (for example, cow) feed would affect digestion and fermentation in the rumen (the first stomach). Using a lab method called the Menke gas method, we tested how VFAs impact gas production, including methane. The results showed that VFAs can replace some of the energy usually provided by silage and concentrate without disrupting the fermentation process. Specifically, replacing 10% of the energy from silage and 20% from concentrate with VFAs in a mixed feed could reduce methane emissions while supplying enough energy for the animals. This approach benefits society by reducing waste from food and agriculture, lowering methane emissions from livestock, and producing more sustainable meat and dairy products. The growing demand for sustainable ruminant feed alternatives has motivated the application of bioconversion approaches for the valorization of agro-food byproducts (AFB) into feed additives and supplements. The present study thoroughly investigated substituting volatile fatty acids (VFAs) obtained from acidogenic fermentation (AF) of AFB as an energy source in ruminant feed. Rumen in vitro digestibility assays were conducted utilizing the gas production method, wherein the VFAs obtained from AF of apple pomace and potato protein liquor was substituted with partial silage and concentrate energy at levels of 10%, 20%, and 30%. The results indicate that substituting 20% of the concentrate's energy with VFA mixture significantly reduced methane production and had no adverse effect on the production and accumulation of VFAs in the simulated rumen media. Conversely, replacing 10% of the silage energy with VFAs led to a decrease in methane production and further enhanced the production of VFAs. Readily digestible VFAs in ruminant feed have the potential to enhance energy availability and sustainability in ruminant farming practices, aligning with the principles of circular economy and waste valorization. [ABSTRACT FROM AUTHOR]