Cricket Meal (Gryllus bimaculatus) as a Protein Supplement on In Vitro Fermentation Characteristics and Methane Mitigation

SIMPLE SUMMARY: Protein sources of high quality and sustainability are found in insects. In many regions, insects are a primary food source, such as in Africa, South America, Asia, and Oceania. Insects are considered promising alternative feed sources, in particular as a source of protein. The use of edible insects as high-protein sources is widespread, and cricket has been proved to be a potential food and feed insect species. Cricket (Gryllus bimaculatus) also contain 54.10% crude protein, 6.90% crude fiber, 26.90% fat, and 78.90% total digestible nutrient, as well as a variety of essential amino acids, including methionine, lysine, histidine, valine, and leucine. In addition, insects have been investigated as a source of protein in diets of poultry, swine, and fish. However, there are currently little data on the utilization of insects as ruminant feed. The objective of this experiment was to conduct the effects of Cricket meal (Gryllus bimaculatus) (CM) as a protein replacement for soybean meal on in vitro fermentation end products, gas production, nutrient degradability, and methane mitigation. ABSTRACT: The aim of this work was to conduct the effects of cricket (Gryllus bimaculatus) meal (CM) as a protein supplement on in vitro gas production, rumen fermentation, and methane (CH(4)) mitigation. Dietary treatments were randomly assigned using a completely randomized design (CRD) with a 2 × 5 factorial arrangement. The first factor was two ratios of roughage to concentrate (R:C at 60:40 and 40:60), and the second factor was the level of CM to replace soybean meal (SBM) in a concentrate ratio at 100:0, 75:25, 50:50, 25:75, and 0:100, respectively. It was found that in vitro DM degradability and the concentration of propionic (C(3)) were significantly increased (p < 0.05), while the potential extent of gas production (a + b), acetate (C(2)), acetate and propionate (C(2):C(3)) ratio, and protozoal population were reduced (p < 0.05) by lowering the R:C ratio and the replacement of SBM by CM. In addition, rumen CH(4) production was mitigated (p < 0.05) with increasing levels of CM for SBM. In this study, CM has the potential to improve rumen fermentation by enhancing C(3) concentration and DM degradability, reduced methane production, and C(2):C(3) ratio. The effects were more pronounced (p < 0.05) at low levels of roughage.