Studi Modifikasi Ransum Berbasis Dietary Cation-Anion Difference (DCAD) terhadap Fermentasi Rumen dan Kecernaan Serat secara In Vitro

Abstract

Pemberian ransum dengan DCAD negatif masih dijumpai pada fase awal laktasi di peternakan rakyat yang berisiko menurunkan pH rumen dan kecernaan serat. Penelitian ini bertujuan mengetahui pengaruh DCAD terhadap fermentasi dan kecernaan fraksi serat secara in vitro, menilai efektivitas variasi imbangan buffer dalam mensimulasikan kondisi fermentasi asam, serta menguji kinerja kantong nilon sebagai alternatif kantong impor dalam analisis serat. Penelitian dilakukan dalam tiga tahapan. Tahap 1 dan 2 menggunakan metode in vitro Tilley dan Terry dengan rancangan acak kelompok faktorial 5×4, mencakup lima taraf DCAD (-71, 0, +50, +100, +200 mEq kg-1) dan empat rasio rumen-buffer-akuades (10:40, 10:30:10, 10:20:20, 10:10:30 mL). Tahap 3 menggunakan ANKOM fiber analyzer dengan rancangan acak lengkap faktorial 3×6, berdasarkan jenis pakan (rumput gajah, jagung, ransum) dan jenis kantong nilon (ANKOM, Gerhardt, Parasut, N57, Abutai, Organza). Hasil menunjukkan bahwa imbangan buffer berpengaruh signifikan terhadap pH rumen, populasi mikroba, NH3, VFA total, serta kecernaan bahan kering, organik, dan fraksi serat. DCAD berpengaruh nyata terhadap protozoa, NH3, volatile fatty acids (VFA) total, dan kecernaan serat dengan interaksi signifikan antara kedua faktor pada protozoa dan VFA total. Kantong N57 dan Abutai menunjukkan hasil serat kasar (SK), neutral detergent fiber (NDF), dan acid detergent fiber (ADF) yang sebanding dengan kantong impor. Simpulan menunjukkan bahwa imbangan buffer berperan penting dalam menjaga stabilitas pH dan aktivitas mikroba rumen secara in vitro. Efektivitas DCAD hanya optimal pada pH di atas 6,6. Selain itu, kantong nilon N57 dan Abutai layak digunakan sebagai alternatif impor untuk efisiensi analisis serat.

The use of diets with negative DCAD is still found during early lactation on smallholder dairy farms, posing a risk of lowering rumen pH and fiber digestibility. This study aimed to evaluate the effects of dietary DCAD on fermentation and fiber digestibility in vitro, assess buffer ratio variations in simulating acidic fermentation conditions, and examine the performance of local nylon bags as alternatives to imported ones in fiber analysis. The research was conducted in three stages. Stages 1 and 2 employed the Tilley and Terry in vitro method using a 5×4 factorial randomized block design, consisting of five DCAD levels (-71, 0, +50, +100, +200 mEq kg-1) and four rumen-buffer-distilled water ratios (10:40, 10:30:10, 10:20:20, 10:10:30 mL). Stage 3 used the ANKOM fiber analyzer with a 3×6 factorial completely randomized design based on feed type (elephant grass, corn, total mixed ration) and bag type (ANKOM, Gerhardt, Parasut, N57, Abutai, Organza). Results showed that buffer ratio significantly affected rumen pH, microbial population, NH3, volatile fatty acids (VFA), and the digestibility of dry matter, organic matter, and fiber fractions. DCAD had significant effects on protozoa, NH3, total VFA, and fiber digestibility, with a significant interaction between DCAD and buffer on protozoa and VFA. The N57 and Abutai bags showed comparable crude fiber (SK), neutral detergent fiber (NDF), and acid detergent fiber (ADF) values to imported bags. In conclusion, buffer ratio plays a critical role in maintaining rumen pH and microbial activity in vitro, while DCAD is only effective above pH 6.6. These local bags are viable, cost-efficient alternatives for fiber analysis.