Aim:This experiment aimed to evaluate substitution of soybean meal (SBM) by black soldier fly (BSF) larvae meal in a napier grass diet as performed by an in vitro rumen fermentation system.Materials and Methods:Samples of napier grass, SBM, and BSF larvae age 1 week (BSF1) and 2 weeks (BSF2) were arranged according to the following dietary treatments (dry matter [DM] basis): T1, 100% napier grass; T2, 60% napier grass + 40% SBM; T3, 60% napier grass + 40% BSF1; T4, 60% napier grass + 40% BSF2; T5, 60% napier grass + 20% SBM + 20% BSF1; and T6, 60% napier grass + 20% SBM + 20% BSF2. The samples were determined for their chemical composition and were incubated in vitro using buffered rumen fluid for 48 h at 39°C. In vitro incubation was carried out in three runs and represented by two incubation bottles per run.Results:Supplementation of BSF, both BSF1 and BSF2, increased ether extract, neutral- and acid-detergent insoluble crude protein contents of T3-T6 diets. The T3 or T4 diet resulted in lower ruminal ammonia concentration, in vitro DM digestibility, and in vitro organic matter (OM) digestibility as compared to those in T2 (p<0.05). Diet supplemented with BSF produced lower methane emission in comparison to that of supplemented with SBM (p<0.05). Diet containing BSF2 produced lower methane and methane per digestible OM than that containing BSF1 (p<0.05).Conclusion:Substitution of SBM by BSF in ruminant diet results in a lower nutritional value in vitro but with an advantage of lowering ruminal methane emission.

ABSTRAKPenelitian ini bertujuan untuk mengevaluasi kandungan nutrien, fermentasi rumen, kecernaan dan emisi metana secara in vitro sejumlah serangga yakni jangkrik (JFC), ulat hongkong (MW) dan larva black soldier fly berumur 1 dan 2 minggu (BSF1 dan BSF2). Sampel serangga dikeringkan pada suhu 60 o C selama 24 jam, kemudian digiling berukuran 1 mm. Sampel yang telah digiling kemudian dianalisis kandungan nutriennya serta diuji secara in vitro. Inkubasi in vitro dilakukan pada water bath pada suhu 39ºC selama 48 h, serta dilakukan dalam tiga ulangan di mana masing-masing ulangan direpresentasikan dengan dua botol inkubasi. Hasil menunjukkan bahwa semua serangga yang diujikan mengandung protein kasar yang tinggi yakni di atas 40% BK. Proporsi neutral detergent insoluble CP (NDICP) dan neutral detergent insoluble CP (ADICP) pada serangga lebih tinggi dibandingkan dengan bungkil kedelai, terutama sangat tinggi pada BSF2. Konsentrasi NH 3 tertinggi terdapat pada inkubasi JFC dibandingkan dengan yang lain (P<0,05) dan paling rendah pada BSF2. Semua sampel serangga memiliki KCBK dan KCBO yang lebih rendah dibandingkan dengan bungkil kedelai (P<0,05). Emisi metana dari serangga pada jam inkubasi ke-12, 24 dan 48 jam lebih rendah dibandingkan dengan bungkil kedelai (P<0,05). Disimpulkan bahwa serangga tinggi akan protein dan menghasilkan emisi metana yang rendah, namun kecernaannya relatif rendah sehingga dapat membatasi penggunaannya. Kata Kunci: serangga, jangkrik, ulat hongkong, black soldier fly, fermentasi rumen ABSTRACTThis experiment was aimed to evaluate chemical composition, in vitro rumen fermentation, digestibility and methane emissions of some insects, i.e. Jamaican field cricket (JFC), mealworm (MW) and black soldier fly larvae age 1 and 2 weeks (BSF1 and BSF2). Insect samples were oven-dried at 60 o C for 24 h, and ground to pass a 1 mm sieve. The ground samples were used subsequently for chemical composition determination and in vitro rumen fermentation test. Incubation was carried out in a water bath maintained at 39 ºC for 48 h in three replicates. Results revealed that all insect meals contained high crude protein, i.e. above 40% DM. Proportions of neutral detergent insoluble CP (NDICP) and neutral detergent insoluble CP (ADICP) were high in the insect meals than that of soybean meal (SBM), and these were particularly very high in BSF2. All insect meals had lower IVDMD and IVOMD than that of SBM (P<0.05). All insect meals had lower methane emissions as compared to SBM at 12, 24 and 48 h (P<0.05). It can be concluded that insect meals are potential protein supplements and have low methane emissions in vitro. However, their digestibility is rather low and may limit their utilization.