## 2 Materials and Methods  
### Typha Samples Collection, Silage Preparation, and Silage Processing  
Samples of wild typha (_Typha latifolia_) were harvested manually at different points from water ways with a high level of leachate close to agricultural fields. The sampling area was located in the southwest of Spain (Valdeobispo, Caceres, Spain, (40\({}^{\circ}\)4\({}^{\prime}\)55\({}^{\prime\prime}\) North; 6\({}^{\circ}\)14\({}^{\prime}\)51\({}^{\prime\prime}\) West) during the period of May 2019. The climate of this area is subtropical Mediterranean, with average annual temperatures ranging between 15\({}^{\circ}\) and 18 \({}^{\circ}\)C. Winters are mild (average of 8 \({}^{\circ}\)C) and summers are dry and hot, reaching absolute maximums of 39 \({}^{\circ}\)C. The plants were collected during the vegetative stage before blooming, at about 2-3 months old, and they were between 1.5 and 2 m high. After collection, the roots were immediately separated and discarded, and the leaves and stems were transported to the laboratory. The plant biomass was pre-wilted outdoors for 36 h to increase their dry matter (DM) content to about 47% before ensiling. Finally, the plants were cut manually into about 2 \(\times\) 3 cm pieces using scissors. The experimental design involved 4 different silage types, with three replicates per treatment. Typha was ensiled without any additive (control); with formic acid (4 mL/kg of plant biomass; FA); with urea and molasses (19 and 34 g/kg of plant biomass, respectively; UM); and with formic acid, urea, and molasses (all additives at the previous concentrations; FAUM). The amount of each additive was selected from previous studies reported in the literature [8]. All silages were created in vacuum-_packed_ plastic bags (25 \(\times\) 40 cm). Three bags per silage treatment were prepared, making a total of 12 silage bags. The typha biomass (400 g) was weighed in a plastic bucket and treated with the corresponding additive. The corresponding amount of additive for each treatment was solubilized in 130 mL of water, and the solution was added to the plastic bucked and mixed thoroughly with the typha. For the control silages, 130 mL of water was added to the bucket. The amount of water added was calculated from the DM determination of the typha to achieve a target DM of 30-34% in the silages. The mixture was then quantitatively transferred into plastic bags that were sealed using an automatic vacuum-packing machine (Model VM 101H, UniVac, Weesp, The Netherlands). In addition, samples of pre-wilted typha were collected during the process of preparing the silages for chemical composition analysis and in vitro incubations. A detailed description of the sampling and biomass preparation was previously given at a conference [9]. The silages were stored in darkness for 4 months at room temperature (20 \({}^{\circ}\)C) before being processed, as described by [PERSON] et al. [10]. Briefly, the bags were opened, their content was weighed, and they were homogenized through hand mixing. Then, 50 g from each silage bag was immediately weighed, mixed with 500 mL of demineralized water, and the mixture was homogenized in a Waring blender (Waring 24 CB10; Waring Commercial, New Hartford, CT, USA) for 40 s. The mixing procedure was repeated after 1 min to prevent heating. The mixture was filtered through 4 layers of cheesecloth, and the pH of the filtrate (silage extract) was immediately measured using a pH meter Crison GPL 21 (Crison Instruments, Barcelona, Spain). Then, 2 ml of the extract was mixed with 40 \(\mu\)L of H\({}_{2}\)SO\({}_{4}\) (20%; vol/vol) for preservation and immediately frozen at \(-\)20 \({}^{\circ}\)C until analysis of the volatile fatty acids (VFA), NH\({}_{3}\)-N, and lactic acid. In addition, 50 g of content from each silage bag was weighed and dried at 60 \({}^{\circ}\)C for 48 h for determining the DM content.