In vitro rumen fermentation of complete feed based on local feed ingredients with different ratios of protein degradability to non-fibrous carbohydrate

The objective of this study was to clarify in vitro ruminal fermentation of complete feeds with different ruminal degradable protein (RDP) - non-fibrous carbohydrate (NFC) ratios. The four complete feeds were formulated using local feed ingredients. Four feed treatments of RDP-NFC ratios were T1 = 0.32 (10.35:32.70); T2 = 0.29 (9.89:34.49); T3 = 0.26 (9.61: 37.45) and T4 = 0.23 (9.36:39.78). The parameters assessed were in vitro gas production (IVGP), feed rumen fermentability and microbial protein synthesis (MPS). The results showed that cumulative IVGP in T1 and T2 were higher than in T3 and T4 (P<0.05). However, the IVGP efficiency in T3 did not differ significantly from that observed in T1 and T2, nor was there a significant difference in T4. The molarities of individual VFAs were not differ significantly between treatments (P>0.05), other than isobutyrate. The isobutyrate molarity in T2 was lower than the others (P<0.05). The concentration and efficiency of MPS in T2, T3, and T4 were higher than in T1 (P<0.05). In conclusion, an RDP-NFC ratio of 0.26 (9.61:37.45) in complete feed has optimal effects on ruminal fermentation and MPS.