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Methane is a potent but short-lived greenhouse gas targeted for short-term amelioration of climate change, with enteric methane emitted by ruminants being the most important anthropogenic source of methane. Ruminant production also releases nitrogen to the environment, resulting in groundwater pollution and emissions of greenhouse gas nitrous oxide. We hypothesized that inhibiting rumen methanogenesis in dairy cows with chemical inhibitor 3-nitrooxypropanol (3-NOP) would redirect metabolic hydrogen towards synthesis of microbial amino acids. Our objective was to investigate the effects of 3-NOP on methane emissions, rumen fermentation and nitrogen metabolism of dairy cows fed true protein or urea as nitrogen sources. Eight ruminally-cannulated cows were fed a plant protein or a urea-containing diet during a Control experimental period followed by a methanogenesis inhibition period with 3-NOP supplementation. All diets were unintentionally deficient in nitrogen, and diets supplemented with 3-NOP had higher fiber than diets fed in the Control period. Higher dietary fiber content in the 3-NOP period would be expected to cause higher methane emissions; however, methane emissions adjusted by dry matter and digested organic matter intake were 54% lower with 3-NOP supplementation. Also, despite of the more fibrous diet, 3-NOP shifted rumen fermentation from acetate to propionate. The post-feeding rumen ammonium peak was substantially lower in the 3-NOP period, although that did not translate into greater rumen microbial protein production nor lesser nitrogen excretion in urine. Presumably, because all diets resulted in low rumen ammonium, and intake of digestible organic matter was lower in the 3-NOP period compared to the Control period, the synthesis of microbial amino acids was limited by nitrogen and energy, precluding the evaluation of our hypothesis. Supplementation with 3-NOP was highly effective at decreasing methane emissions with a lower quality diet, both with true protein and urea as nitrogen sources.

3-Nitrooxypropanol (3-NOP) supplementation to cattle diets mitigates enteric CH4 emissions and may also be economically beneficial at farm level. However, the wider rumen metabolic response to methanogenic inhibition by 3-NOP and the NO2- intermediary metabolite requires further exploration. Furthermore, NO3- supplementation potently decreases CH4 emissions from cattle. The reduction of NO3- utilizes H2 and yields NO2- , the latter of which may also inhibit rumen methanogens, although a different mode of action than for 3-NOP and its NO2- derivative was hypothesized. Our objective was to explore potential responses of the fermentative and methanogenic metabolism in the rumen to 3-NOP, NO3- and their metabolic derivatives using a dynamic mechanistic modeling approach. An extant mechanistic rumen fermentation model with state variables for carbohydrate substrates, bacteria and protozoa, gaseous and dissolved fermentation end products and methanogens was extended with a state variable of either 3-NOP or NO3- . Both new models were further extended with a NO2- state variable, with NO2- exerting methanogenic inhibition, although the modes of action of 3-NOP-derived and NO3- -derived NO2- are different. Feed composition and intake rate (twice daily feeding regime), and supplement inclusion were used as model inputs. Model parameters were estimated to experimental data collected from the literature. The extended 3-NOP and NO3- models both predicted a marked peak in H2 emission shortly after feeding, the magnitude of which increased with higher doses of supplement inclusion. The H2 emission rate appeared positively related to decreased acetate proportions and increased propionate and butyrate proportions. A decreased CH4 emission rate was associated with 3-NOP and NO3- supplementation. Omission of the NO2- state variable from the 3-NOP model did not change the overall dynamics of H2 and CH4 emission and other metabolites. However, omitting the NO2- state variable from the NO3- model did substantially change the dynamics of H2 and CH4 emissions indicated by a decrease in both H2 and CH4 emission after feeding. Simulations do not point to a strong relationship between methanogenic inhibition and the rate of NO3- and NO2- formation upon 3-NOP supplementation, whereas the metabolic response to NO3- supplementation may largely depend on methanogenic inhibition by NO2- .

Simple Summary: The beef industry faces significant challenges in increasing red protein production given the growing population, with projections to be approximately 28% higher by 2050. Additionally, there are increasing government and public pressures for all industries to mitigate greenhouse gases, which include methane. The livestock industry contributes approximately 14.5% of greenhouse gas emissions attributed to human activities. This study investigated the combination of the methane inhibitor 3-nitrooxypropanol with monensin sodium or a feed additive package consisting of essential oils, 25-Hydroxy-Vitamin-D3, an active metabolite of vitamin D3, and carbo-amino-phospho-chelated minerals such as chromium and zinc. The results showed that 3-nitrooxypropanol, regardless of the combination used, reduced daily enteric methane emissions by over 38%, in addition to increasing feed conversion by over 6% when combined with monensin sodium compared to the treatment without 3-nitrooxypropanol. Furthermore, the combination of 3-nitrooxypropanol with the additive package showed better conditions in growth performance, carcass traits, meat quality, blood parameters, and nutrient intake and digestibility. This offers the meat industry more nutritional strategies to meet the growing demand for protein while reducing environmental impacts. The objective of this study was to evaluate the effect of 3-nitrooxypropanol (3-NOP) in combination with different feed additives on growth performance, carcass traits, meat quality, enteric methane (CH4) emissions, nutrient intake and digestibility, and blood parameters in feedlot beef cattle. In experiment (Exp.) 1, one hundred sixty-eight Nellore bulls (initial bodyweight (BW) 410 ± 8 kg) were allocated to 24 pens in a completely randomized block design. In Exp. 2, thirty Nellore bulls (initial BW 410 ± 3 kg) were allocated to a collective pen as one group, and treatments were allocated in a completely randomized design. Three treatments were applied: Control (CTL): monensin sodium (26 mg/kg of dry matter, DM); M3NOP: CTL with 3-NOP (100 mg/kg DM); and Combo: 3-NOP (100 mg/kg DM) with essential oils (100 mg/kg DM), 25-Hydroxy-Vitamin-D3 (0.10 mg/kg DM), organic chromium (4 mg/kg DM), and zinc (60 mg/kg DM). In Exp. 1, bulls in the Combo group had greater (p < 0.01) dry matter intake (DMI) at d 28 compared to the CTL and M3NOP groups. During d 0 to 102, bulls' final BW and average daily gain (ADG) were greater (p ≤ 0.03) for the Combo group compared to the CTL. The bulls in the Combo and M3NOP groups had better (p < 0.01) feed conversion (FC) and feed efficiency (FE) compared to the CTL. Hot carcass weight (HCW), carcass ADG, and carcass yield were greater (p ≤ 0.05) for bulls in the Combo group compared to the CTL and M3NOP groups. The bulls in the Combo group had greater (p = 0.01) dressing compared to the M3NOP group. Combo bulls had better (p = 0.02) biological efficiency compared to the CTL. The bulls in the Combo group had lower (p < 0.01) carcass pH compared to the CTL and M3NOP groups. In Exp. 2, bulls in the Combo group had greater (p = 0.04) DMI at d 28 compared to the CTL and had greater (p < 0.01) DMI at d 102 compared to the CTL and M3NOP groups. The bulls in the Combo group had greater (p = 0.04) HCW compared to the CTL and M3NOP groups and carcass ADG was greater (p = 0.04) for bulls in the Combo group compared to the M3NOP group. The bulls in the Combo and M3NOP groups had lower (p < 0.01) CH4 production (38.8%, g/d), yield (41.1%, g/kg DMI), and intensity (40.8%, g/kg carcass ADG) and higher (p < 0.01) H2 emissions (291%, g/d) compared to the CTL. Combo bulls had lower (p < 0.01) blood glucose and insulin, and higher nutrient intake and digestibility (p ≤ 0.05) compared to the CTL and M3NOP groups. Combining 3-NOP with different feed additives improved FC and FE, and reduced enteric CH4 emissions. Combo treatment improved growth performance, carcass traits, nutrient intake, and digestibility, and improved glucose and insulin responses in feedlot beef cattle on a high-concentrate finishing diet. [ABSTRACT FROM AUTHOR]

Simple Summary: This study was conducted with the primary aim of assessing the dosage of 3-nitrooxypropanol, its effectiveness in methane mitigation performance of feedlot cattle, and its impact on the quality of meat. The results obtained through its application have already demonstrated its efficacy as an additive for methane reduction. Consequently, further research is warranted to confirm its suitability for use in commercial production. 30 Nellore animals with an average weight of 407.25 ± 2.04 kg, were distributed in a completely randomized design across the following treatments: 1—Control (without inclusion of 3-NOP); 2—BV75 (inclusion of 3-NOP at 75 mg/kg DM); 3—BV100 (inclusion of 3-NOP at 100 mg/kg DM). No significant effects were observed between treatments on ingestive behavior. However, the notable effect on the BWfinal and ADG of animals supplemented with 3-NOP compared to the control group was measurable. Cattle beef receiving 3-NOP exhibited reduced methane emissions (p < 0.0001) for all variables analyzed, resulting in an average decrease of 38.2% in methane emissions compared to the control, along with increased hydrogen emissions (g/day) (p < 0.0001). While supplementation with BV100 demonstrated lower methane emission, the performance was lower than BV75 in DMI, BWfinal, ADG, and ADG carcasses. Partial separation of metabolomics observed between groups indicated changes in meat metabolism when comparing the control group with the 3-NOP group, identifying metabolites with a variable importance projection (VIP) score > 1. In conclusion, supplementation with 3-NOP effectively reduced methane emissions and did not negatively influence animal performance. [ABSTRACT FROM AUTHOR]

There is an urgent requirement internationally to reduce enteric methane (CH4) emissions from ruminants to meet greenhouse gas emissions reduction targets. Dietary supplementation with feed additives is one possible strategy under investigation as an effective solution. The effects of the CH4 inhibitor 3-nitrooxypropanol (3-NOP) at reducing CH4 emissions in beef have been shown mainly in adult cattle consuming backgrounding and high-energy finishing diets. In this study, the effects of dietary supplementation of young growing (≤6 mo) beef cattle with 3-NOP were examined in a 50:50 forage:concentrate diet. A total of 68 Dairy × Beef (Aberdeen Angus and Hereford dairy cross) male calves (≤6 mo of age at the start of experiment, body weight: 147 ± 38 kg) underwent a 3-wk acclimatization period and were then assigned to one of two treatments in a completely randomized block design. Dietary treatments were (1) control, placebo (no 3-NOP), and (2) 3-NOP applied at 150 mg kg−1 DM. Calves were fed a partial mixed ration for 12 wk. Body weight was recorded weekly and feed intake daily using the Calan Broadbent feeding system. Methane and hydrogen emissions were measured using the GreenFeed system. Total weight gained, dry matter intake (DMI), and average daily gain were not affected by 3-NOP (P  > 0.05) supplementation. On average, the inclusion of 3-NOP decreased (P  < 0.001) CH4 emissions: g d−1; g kg−1 DMI; by 30.6% and 27.2%, respectively, during the study with a greater reduction occurring over time. Incorporating 3-NOP into beef cattle diets is an efficient solution to decrease CH4 emissions during indoor feeding and when offered 50:50 forage:concentrate diet. [ABSTRACT FROM AUTHOR]

The objective was to assess the impact of combining 3-nitrooxypropanol (3-NOP; Bovaer) with different feed additives on performance, carcass characteristics and meat quality. Young Nellore bulls (n = 164), aged 16 ± 1 mo with body weight (BW) = 410 ± 3 kg, were randomly allocated to 24 pens. There were three treatments, each with 8 replications (pens) per treatment and 7 animals per pen. The animals were fed a high-concentrate feedlot diet (R:C, 10:90) for 102 d, according with the following three treatments: 1) Control: Sodium Monensin [26 mg/kg dry matter (DM)]; 2) BOV: Control + 3-NOP (Bovaer; 100 mg/ kg DM); 3) BOVPERF (Bovaer Performance pack): Control + 3-NOP (100 mg/kg DM) + Essential oils (Crina Ruminants, 100 mg/kg DM) + 25-OH-Vitamin D3 (Hy-D, 0.10 mg/kg DM) + carbo-amino-phospho- chelate of chromium and zinc (0.40 and 60 mg/kg of DM, respectively). The BW of yearling bulls were recorded at the beginning, the end of the adaptation period (28 d), and the conclusion of the experiment after a 16-h feed withholding period to facilitate the recording of shrunk BW. Based on these BW, it was possible to conduct analyses of the performance during the periods of 28 and 102 d of the experiment. Additionally, carcass characteristics were evaluated, along with assessments of the meat quality of these animals subjected to different treatments. Data were analyzed by ANOVA using the PROC MIXED of SAS 9.4 and means and contrast comparison evaluated by Tukey test at P < 0.05. Feeding BOVPERF increased DM intake during the adaptation period (P < 0.01) compared with control and BOV. However, the control group showed a greater conversion ratio (P < 0.01) and feed efficiency (P < 0.01) compared with BOV and BOVPERF at 102 d of the feedlot. There was a greater increase in hot carcass weight (HCW) with a difference of (+12 kg, P > 0.01), greater carcass ADG (+113 g/d, P < 0.01), followed by a greater dressing percentage (P < 0.01), greater carcass gain yield (P < 0.01), and better biological efficiency (- 9 kg diet in DM kg/15 kg of HCW, P = 0.02) for BOVPERF compared with control and BOV. Additionally, when analyzing meat quality characteristics, a significant difference (P < 0.01) in pH values was observed for BOVPERF compared with control and BOV. In conclusion, the combination of 3-NOP with essential oils, 25-hydroxy-vitamin D3, and minerals such as chromium and zinc demonstrated positive effects on various aspects, including increased performance, carcass characteristics and meat quality. [ABSTRACT FROM AUTHOR]

Our objective was to evaluate the effects of 3-Nitrooxypropanol (3-NOP) associated with different feed additives on performance, carcass characteristics and enteric methane (CH4) emissions. Twenty-seven Nellore bulls (initial BW, 410 ± 6 kg) were randomly allocated to three treatments with nine replicates per treatment (animal as experimental unit). The animals were fed a high-concentrate feedlot diet (R:C, 10:90) for 102 days, according with the following three treatments: 1) Control (CTRL): Sodium Monensin (26 mg/kg DM); 2) BOV: Control + 3-NOP (Bovaer;100 mg/kg DM); 3) BOVPERF (Bovaer Performance pack): Control + 3-NOP (100 mg/kg DM) + Essential oils (Crina Ruminants, 100 mg/kg DM) + 25-OH-Vitamin D3 (Hy-D, 0.10 mg/kg DM) + carbo-amino-phosphochelate of chromium and zinc (0.4 and 60 mg/kg of DM, respectively). The gases emissions (CH4 and H2) and DMI variables were assessed individually, by using the GreenFeed and Intergado electronic system placed in the feedlot pen, respectively. The BW of Yearling bulls were recorded at the beginning and final of the experiment after 16-h fasting (Table). Data were analyzed by ANOVA using the PROC MIXED of SAS 9.4, in which means comparison were evaluated by Tukey test at P < 0.05. Feeding BOVPERF increased DM intake during adaptation period (P = 0.04), and over the total period (P < 0.01) compared with control with no difference on feed efficiency (P =0.61). There was no difference (P > 0.05) on DMI between CTRL and BOV. Animals fed BOVPERF had greater HCW (+13 kg, P = 0.04) and greater carcass ADG (+120 g/d, P = 0.04) compared with CTRL. Animals fed BOV and BOVPERF emitted 39% less CH4 (P < 0.01) and produced 292% more H2 (P < 0.01) compared with CTRL. In addition, there were significant reductions in methane intensity, as measured by the ratios CH4/kg DM (-42%; P < 0.01), and CH4/kg carcass ADG (-41.13%; P < 0.01) for animals fed with BOV and BOVPERF compared with CTRL. We conclude that feeding Bovaer performance pack reduces methane emissions and increases carcass production in feedlot beef cattle. [ABSTRACT FROM AUTHOR]

A new approach to induce protein dimerization in vivo, based on the covalent labeling of fusion proteins with ligands capable of interacting with other proteins is presented. The high specificity of the covalent labeling reaction allows the approach to become an important tool for studying and controlling protein dimerization in biological processes.

Our objective was to evaluate the effects of 3-nitrooxypropanol (3-NOP, Bovaer, DSM Nutritional Products) at different levels in feedlot beef cattle diets on productive performance, biological efficiency, and methane (CH4) emissions. Thirty Nellore bulls (iBW, 407 ± 6 kg) were randomly assigned to three treatments with ten replicates (animal) per treatment. The animals were fed a high-concentrate feedlot diet for 87 days, according to the three treatments: 1) 0, Control (no addition of 3-NOP); 2) Bovaer75 (75 mg/kg DM of 3-NOP), 3) Bovaer100 (100 mg/kg DM of 3-NOP,). Gas emissions (CH4 and H2) were evaluated individually using the GreenFeed unit (C-Lock, USA), while the variables of dry matter intake (DMI) were evaluated using digital feeders (Intergado System, Brazil). Body weights of yearling bulls were recorded after 16-h fasting at the beginning and end of the experiment. Data were submitted to be analyzed using PROC MIXED from SAS 9.4, evaluated by orthogonal contrasts, with a significance level of 5%. Initial BW was used as a covariate when significant to adjust the statistic model. No differences on DMI (kg/d and %BW, P = 0.323) were observed between control animals and those fed with Bovaer. Animals fed with Bovaer75 had greater ADG than control and Bovaer100, (1.73 vs. 1.63 and 1.60 kg/d; P = 0.038 and P = 0.025, respectively) and better biological efficiency than control (~127.0 vs 135.3 kg DMI/15 kg carcass produced, P < 0.023). A similar result was observed for carcass gain, in which animals supplemented with Bovaer 75 had greater gains than the control. Animals fed 75 and 100 mg/kg DM of Bovaer emitted respectively 33.7% and 42.7% less methane per se (g/d, P < 0.01) compared with control, and additionally produced more hydrogen (P < 0.01) vs control. There were significant reductions in the measured methane yield in relation to DMI (CH4: DMI, P < 0.01) and methane intensity (CH4/ADG, P < 0.01) for animals fed the two levels of Bovaer, in comparison with the control, as well as a significant difference in the reduction of CH4 in relation to the biological efficiency for the animals fed with Bovaer (P < 0.01). We conclude that feeding Bovaer consistently reduces methane emission from feedlot cattle, in which the reduction intensity increased over the dosages evaluated in the current study. [ABSTRACT FROM AUTHOR]

A general method for immobilization of proteins that are genetically linked to a mutant of the human DNA repair protein O(super 6)-alkylguanine-DNA alkytlransferase (hAGT) is reported. The high specificity and covalent nature of the approach make it an attractive alternative to the currently used protocols for the immobilization of fusion proteins.