Relationships between dry matter degradation, in vitro gas production and chemical composition of 15 feedstuffs
This study was designed to investigate the relationships of in vitro true digestibility of dry matter (IVTD) and in vitro gas production of feedstuffs. 15 ruminant feedstuffs which were selected in Xinjiang province in China (corn, corn bran, bran, cottonseed meal, soybean meal, DDGS, urea gelatinized corn protein, corn gluten meal, monosodium glutamate residue, grape seed meal, cottonseed hulls, alfalfa meal, alfalfa hay, corn silage and tomato sauce residue). Gas production, volatile fatty acid (VFA) and IVTD at 24h incubation were measured. Statistical analysis was performed using the PROC CORR procedure of SAS 9.1. The results revealed that strong negative correlation was observed between neutral detergent fiber (NDF) and IVTD (r2=0.81, P< 0.001). Positive correlation was observed between non-fibern carbohydrate (NFC) and IVTD (r2=0.74, P< 0.001). In vitro gas production at 24h was negatively related with NDF content (r2=0.54, P< 0.05) and positively related with NFC content (r2=0.92, P< 0.001). In vitro gas production at 24h was positively related with total VFA production (r2=0.93, P < 0.001). There was strong positive correlation between NFC content and total VFA production (r2=0.81, P< 0.001). Therefore, chemical composition of feedstuffs were highly related with in vitro gas production, in vitro true digestibility of dry matter.
Keywords: chemical composition, in vitro gas production, in vitro true digestibility of dry matter