摘要：Biofat is a hexane extract containing several bioactive compounds with anacardic acid as the major compound. This study aimed to examine the effect of anacardic acid on rumen fermentation, especially methane and its degradation in the in vitro rumen fermentation. The study was arranged in a completely randomized block design. The treatments were control (substrate or complete feed), biofat (substrate + 0.75 uL/mL biofat), and anacardic acid (substrate + 0.75 uL/mL anacardic acid). Measured variables were total gas production, methane, pH, concentration of ammonia (NH3), dry matter degrability (DMD), organic matter degrability (OMD), and neutral detergent fiber degrability (NDFD) in the rumen. The chromatogram GC-MS analysis results indicated that the anacardic acid isolation process of the biofat produced nearly pure isolate (99.44%), and significantly decreased the production of methane by 51.21% and 39.62%, respectively. Anacardic acid degradation pattern in the in vitro rumen test showed a shifting of retention factor (Rf) value after anacardic acid being incubated with the degradation of anacardic acid occurred after 24 h of fermentation. In conclusion, anacardic acid isolated from biofat has a dominant role to reduce the in vitro methane production. Anacardic acid is very potential to be used as a methane reducing agent.
其他摘要：Biofat adalah produk bioindustri dari kulit cangkang mete yang mengandung beberapa senyawa bioaktif dengan senyawa utama adalah asam anakardat. Penelitian bertujuan untuk menguji efektivitas asam anakardat pada fermentasi rumen, khususnya gas metana dan degradasinya di dalam fermentasi rumen secara in vitro. Penelitian menggunakan rancangan acak kelompok. Perlakuan: kontrol (substrat atau pakan komplit), biofat (substrat + biofat dengan level 0,75 µL/mL), asam anakardat (substrat + asam anakardat dengan level 0,75µL/mL). Peubah yang diukur: produksi gas total, metana, pH, konsentrasi amonia (NH3 ), degradasi bahan kering (DBK), degradasi bahan organik (DBO), dan degradasi serat (DNDF) dalam rumen. Hasil isolasi asam anakardat menghasilkan rendemen sebanyak 8 g dari 10 g biofat. Hasil analisis GC-MS menunjukkan bahwa proses isolasi asam anakardat dari biofat menghasilkan senyawa murni (99,44%) dan dapat menurunkan produksi metana secara signifikan dibanding kontrol, sebesar 51,21% oleh biofat dan 39,62% oleh anakardat. Hasil degradasi asam anakardat dalam fermentasi rumen secara in vitro menunjukkan bahwa perubahan nilai faktor retensi (Rf) setelah diinkubasi. Disimpulkan bahwa asam anakardat yang diisolasi dari biofat memegang peran dominan untuk menurunkan metana pada fermentasi pakan di dalam rumen secara in vitro. Asam anakardat lambat didegradasi oleh bakteri rumen sehingga efektivitasnya dalam menekan gas metana sangat potensial.
