Substitution effects of rice for corn grain in total mixed ration on rumen fermentation characteristics and microbial community in vitro

Abstract

This study determined the substitution effects of rice for corn as the main grain source in a total mixed ration (TMR). In vitro rumen fermentation characteristics and microbes were assessed using two experimental diets. Diets included 33% dry matter (DM) of either corn (Corn TMR) or rice grains (Rice TMR). In a 48-h in vitro incubation, DM digestibility (IVDMD), neutral detergent fiber degradability (IVNDFD), crude protein digestibility (IVCPD), volatile fatty acids (VFAs), pH and ammonia nitrogen (NH 3-N) were estimated. Gas production has been calculated at 3, 6, 12, 24 and 48 h. Our results indicate that the gas production, VFAs, IVDMD, and IVNDFD of Rice TMR were higher than those of Corn TMR (p < 0.05). Ruminal pH and total fungi were significantly higher in Corn TMR (p < 0.05) than in Rice TMR; however, NH 3-N and IVCPD were not affected by treatment type. In conclusion, substituting rice for corn at 33% DM in TMR appears to have no negative effects on in vitro rumen fermentation characteristics. Therefore, rice grains are an appropriate alternative energy source in early fattening stage diets of beef cattle.

Effects of the Use of Rice Grain on Growth Performances, Blood Metabolites, Rumen Fermentation, and Rumen Microbial Community in Fattening Hanwoo Steers

“…Regarding the VFA composition, the proportion of butyrate was higher in the Rice TMR group than in the Corn TMR group. This differed with the findings of Yoo et al [ 10 ], who reported no difference in butyrate proportion between the rice TMR and corn TMR. Ha et al [ 24 ] reported that the normal range for butyrate is 80–150 mmol/mol; therefore, the butyrate proportion in the Rice TMR (149 mmol/mol) fell within the normal range.…”

“…Yoo et al [ 10 ] observed no difference in CP digestibility between corn TMR and rice TMR, and they also found no significant difference in NH 3 -N concentration, which was positively correlated with CP digestibility. Similar to the findings of Yoo et al [ 10 ], our study showed no significant difference in NH 3 -N concentration between the groups fed with Corn TMR (7.12 mg/dL) and Rice TMR (7.33 mg/dL). Moreover, the ruminal NH 3 -N concentration in our study fell within the previously suggested optimal range for proper rumen fermentation (3.3 to 8.5 mg/dL) [ 23 ].…”

“…Subsequently, 200 μL of the resulting supernatant was diluted with 800 μL of 99% anhydrous ethyl alcohol. The concentration of VFA was determined using a gas chromatograph (Agilent 7890A, Agilent Technology, Santa Clara, CA, USA) following the method described in the study by Yoo et al [ 10 ]. The NH 3 -N concentration was determined with certain modifications to the method proposed by Chaney and Marbach [ 11 ], and the assessment was conducted following the procedure outlined by Yoo et al [ 10 ].…”

“…USA) following the method described in the study by Yoo et al [10]. The NH3-N concentration was determined with certain modifications to the method proposed by Chaney and Marbach [11], and the assessment was conducted following the procedure outlined by Yoo et al [10].…”