Effects of 3-nitrooxypropanol on enteric methane production, rumen fermentation, and feeding behavior in beef cattle fed a high-forage or high-grain diet1

Abstract

The objective of the study was to determine whether feeding a diet supplemented with 3-nitrooxypropanol (3-NOP) affects feeding behavior altering intake and rumen fermentation. Two experiments were conducted with 9 rumen-cannulated beef steers in a replicated 3 × 3 Latin square design where animals received a high-forage or high-grain diet. Treatments were 1) a basal diet (CON), the CON diet supplemented with 3-NOP (dNOP; 100 mg/kg in dietary DM or 1 g/d), or the CON diet with 3-NOP (1 g/d) infused into the rumen (infNOP). Each experimental period consisted of 14-d diet adaptation and 7-d sample collection. A 7-d washout period was provided between experiment periods. All data were analyzed as a Latin square design using Mixed Procedure of SAS. In Exp. 1 (high-forage diet), methane yield (measured by the Greenfeed system) was lowered by 18% (18.6 vs. 22.7 g/kg DMI; P < 0.01) by dNOP compared with CON. Rumen fermentation was altered similarly by both NOP treatments compared with CON where dNOP and infNOP increased (P < 0.01) rumen pH at 3 h and decreased (P < 0.01) proportion of acetate in total VFA. However, DMI, feed consumption rate (0 to 3, 3 to 6, 6 to 12, and 12 to 24 h after feeding), particle size distribution of orts, and feeding behavior (videotaped for individual animals over 48 h) were not affected by dNOP and infNOP compared with CON. In Exp. 2 (high-grain diet), methane production was not affected by dNOP or infNOP compared with CON. Dry matter intake, feed consumption rate, particle size distribution of orts, and feeding behavior were not altered by dNOP and infNOP compared with CON. However, both dNOP and infNOP affected rumen fermentation where total VFA decreased (P = 0.04) and acetate proportion in total VFA tended to decrease (P = 0.07) compared with CON. In conclusion, dietary supplementation of 3-NOP did not affect feeding behavior of beef steers fed a high-forage or high-grain diet. However, rumen fermentation was similarly changed when 3-NOP was provided in the diet or directly infused in the rumen. Thus, observed changes in rumen fermentation with 3-NOP were not due to changes in feeding behavior indicating no effects on the organoleptic property of the diets. In addition, according to small or no changes in DMI in both experiments and relatively small changes in rumen fermentation in Exp. 2, a greater dosage level of 3-NOP than 100 mg/kg (dietary DM) may need further examination of its effects on feeding behavior of beef cattle.

The effects of dietary supplementation with 3-nitrooxypropanol on enteric methane emissions, rumen fermentation, and production performance in ruminants: a meta-analysis

“…2019R1F1A1056904). ments methods of CH 4 emissions among all used studies [12][13][14][15][16][17][18][19][20][21][22][23][24][25] (Table 1). In short, the administration methods of NOP were direct administration via cannula, top dressed, and mixed with diet.…”

“…Several studies revealed that NOP supplementation might increase proportion of caproate when high dose of NOP supplemented [21,24], although other studies showed no sig-nificant change [15,20] or significant decrease [14]. Reynolds et al [24] reported NOP significantly increased ethanol production when was supplemented to 2,500 mg/d, and Kim et al [13] observed significant increase of lactic acid when NOP was ruminally infused in high grain diet. A few studies showed increase of several fermentation products as hydrogen sink, more evidence will be needed to understand mechanism of metabolic hydrogen produced from CH 4 reduction by NOP supplementation in rumen.…”

“…In the present meta-analysis, therefore, we hypothesized that NOP supplementation might be affected differently on rumen fermentation characteristics depending upon animal type adding recent in vivo studies which was not included in previous meta-analysis studies [13][14][15]25]. The aim of this study was to investigate the effects of NOP on enteric gas production, rumen fermentation, and animal performances depending on animal type using a meta-analysis approach.…”

“…The NOP is a structural analogue of methyl coenzyme-M, which inhibits the activity of methyl coenzyme-M reductase related to the final step of methanogenesis [11]. Until now, total 14 in vivo studies using NOP supplementation were performed on various domestic ruminants, including sheep [12], beef cattle [13][14][15][16][17][18][19], and dairy cattle [20][21][22][23][24][25]. According to the results of previous studies using NOP in vivo, the CH 4 emissions and proportion of acetate (% total volatile fatty acids, VFA) clearly decreased, whilst the proportion of propionate (% total VFA) significantly increased, but any adverse effects were not detected.…”

Short-Term Eating Preference of Beef Cattle Fed High Forage or High Grain Diets Supplemented with 3-Nitrooxypropanol

“…1 and before starting Exp. 2, the animals were used in another experiment for 4 months [11]. That study was a repeated 3 × 3 Latin square design where the animals received a high forage diet (control), a high forage diet supplemented with 3-NOP (100 mg/kg dietary DM), or the control diet with 3-NOP being infused into the rumen.…”