Study of nyamplung (Calophyllum inophyllum) kernel cake as an alternative protein source for ruminant feed and its effect on methane emission through in vitro

The industry of Nyamplung/tamanu (Calophyllum inophyllum) crude oil is developed massively in Indonesia. The by product of this crude oil is called nyamplung kernel cake (NKC). This study was conducted to investigate the chemical compositions, plant secondary metabolites, and in vitro digestibility of NKC as new alternative feed. In chemical compositions, the NKC contained 90.2 dry matter, 7.92 organic matter, 20.1 crude protein, 15.3 ether extract, 53.3 neutral detergent fiber, 38.2 acid detergent fiber, and 15.1 hemicellulose. In plant secondary metabolites, the NKC contained 6.47 total phenol, 1.70 total flavonoid, and 0.90 saponin. The total tannin of NKC was 0.93 consisting of condense tannin at 0.45 and hydrolysable tannin at 0.48. The chemical compositions of NKC were similar to palm kernel cake (PKC), copra cake (CC), tamarind (Leucaena leucocephala) leaves meal (TLM), gliricida (Glircidia sepium) leaves meal (GLM), and malapari (Pongamia pinnata) kernel cake (MKC). Thus, those feedstuffs were incubated in rumen buffer for 48 h. During ruminal incubation, NKC produced the lowest methane emission without any negative effects on rumen fermentation indices. Moreover, NKC still had a similar digestibility to PKC, CC, and GLM. This study concluded that the NKC can substitute the use of PKC, CC, TLM, GLM, and MKC in the ruminant diet, which can also help to reduce methane emission through in vitro study. © 2023 Fundacion CIPAV. All rights reserved.