Potential of mimosine of Leucaena leucocephala for modulating ruminal nutrient degradability and methanogenesis

In vitro efficacy of cetyltrimethylammonium bromide (CETAB)-modified nano-montmorillonite against aflatoxin B1 associated toxicity and methanogenesis

BACKGROUND

Modified nano-montmorillonite is gaining attention as a feed additive for its benefits on ruminal fermentation. Chemical and mechanical methods were used to modify montmorillonite. Cetyltrimethylammonium bromide (CETAB) was utilized for chemical modification, while grounding was carried out to achieve the desired nanoscale particle size, resulting in the formation of the nanoscale powder known as MNMCETAB. Impacts of MNMCETAB supplementation on a basal diet, either contaminated with aflatoxin B1 (AFB1) or not at a level of 20 ppb were tested. Treatments included control (no supplements), a diet with 5 g per kilogram of dry matter (DM) of natural montmorillonite (NM), and diets with MNMCETAB at two doses, 0.5 (low) and 1 (high) grams per kilogram DM.

RESULTS

The MNMCETAB showed better physicochemical traits than NM clay, including narrower particle size range, higher cation exchange capacity (CEC), greater specific surface area (SSA), and more functional groups. A significant linear decreasing effect (P < 0.05) of MNMCETAB addition on methane (CH) production was observed by the increasing level of the MNMCETAB clay. The control diet contaminated with AFB1 resulted in lower fiber degradability than the other treatments (P < 0.05). No variations were observed in ruminal protozoal counts by both clay supplementations, although there was a noticeable trend (P = 0.08) towards reduced protozoal populations due to AFB1 contamination. AFB1-contaminated diets showed indications of reduced (P < 0.05) levels of total volatile fatty acids (VFA), and concentrations of butyrate and propionate (P < 0.05), alongside shifts towards elevated (P = 0.006) acetate levels, while the low dose of MNMCETAB exhibited higher (P < 0.01) propionate concentrations than the other treatments.

CONCLUSION

These findings underscored the anti-methanogenic properties and the favorable impacts of MNMCETAB in mitigating the adverse impacts of AFB1on ruminal fermentation and nutrient degradability.

Phytochemical profile and in vitro evaluation of cassava (Manihot esculenta Crantz) foliage as ruminant feed with/without green banana flour

Cassava (Manihot esculenta Crantz) is a crucial crop in tropics and subtropics, primarily cultivated for its tuber. However, its foliage is rich in protein and can supply essential elements for ruminants. The objective of this study was to evaluate the phytochemical compounds by Gas chromatography-MS (GC-MS) and the main phenolic by High Pressure Liquid Chromatography (HPLC) present in cassava foliage, along with the fermentation pattern using a semi-automated gas production (GP) system. The in vitro evaluation was carried out for four diets formulated as follows: T1 (alfalfa: grass hay at ratio of 30: 70); T2 (alfalfa: grass hay: banana flour 30:60:10); T3 and T4 (replaced alfalfa in T1 and T2 with cassava foliage, respectively). The addition of green banana flour aimed to increase the diets' energy. The GC-MS results indicated that cassava foliage showed a large number of valuable bioactive components, with the biflavonoid isoginkgetin representing the major component at 25.33% of total peak area percentage. The HPLC analysis declared that rutin, gallic acid, and ferulic acid were the main phenolic compounds presented in cassava foliage ethanolic extract. The accumulative gas after 24 h of incubation was significantly lower with cassava diets compared to alfalfa diets, being 119.3 versus 130.1 ml/g DM, respectively. The degradation of both organic matter and neutral detergent fiber was significantly higher with alfalfa compared to cassava diets, while there was no significant difference between alfalfa and cassava diets on final pH, ammonia concentration and protozoal count. Banana flour inclusion, regardless of the forage type, decreased the accumulative gas after 24 h of incubation with about 9% compared with no banana addition. The use of cassava foliage in ruminant diets considered a promising protein source with valuable bioactive components that could have a positive effect on animal health and production.

Can a blend of integrated feed additives modulate ruminal fermentation patterns and performance of growing lambs? In vitro and in vivo assessments

Two in vitro and in vivo experiments were accomplished to investigate the impacts of integrated feed additives (IFA, combination of protected fat, lysine, and methionine plus yucca extract, eucalyptus essential oil, and direct-fed microbial) on gas production (GP), ruminal fermentation and degradability parameters and lamb performance, digestibility, and nitrogen balance. In the in vitro experiment, responses of graded doses (0, 25, 50, 75, 100, and 125 g IFA/kg DM) were evaluated. In the in vivo experiment, 15 Barki male lambs (30.43 ± 0.74 kg BW ± SE) were individually allotted in complete randomized design into three treatments (five animal/treatment) as control (basal diet without additive), low dose (50 g/kg DM) and high dose (100 g/kg DM) for 120 days. In vitro results showed that both doses (100 and 125 g/kg DM) quadratically decreased (p < 0.001) GP and ammonia nitrogen (NH-3N) concentration. In vivo experiment revealed that dry matter intake was increased (p = 0.016) with low dose compared to high dose. Inclusion of high dose decreased blood serum glucose concentrations (p > 0.05) and ruminal protozoal populations (p = 0.094) compared with low dose and control diet. Both doses of IFA increased (p < 0.05) serum urea, creatinine, and triglyceride concentrations, while decreased (p < 0.001) ruminal NH3-N concentrations. These results suggested that, although IFA was effective to modify in vitro ruminal fermentation process and feed degradability, such aspects did not improve in vivo performance of growing lambs.

In vitro rumen degradability of tropical legumes and their secondary metabolites depends on inoculum source

In this study, the in vitro apparent rumen degradability of organic matter (ARDOM) and plant secondary metabolites (ARDPSM) of three tropical legumes (Mucuna pruriens, Canavalia ensiformis, and Leucaena leucocephala) were assessed. For this, 3 experiments were set up, i.e., single end-point incubations (24 h) with ruminal inoculum from either Belgian or Cuban sheep, as well as kinetic assessments (0 h, 2 h, 4 h, 6 h, 8 h, 10 h, 12 h, and 24 h) inoculum from Belgian sheep. L-mimosine, L-canavanine, Concanavalin A (Con A), and trypsin inhibitor (TI) were the plant secondary metabolites (PSM) targeted in this study. In all three experiments, both beans, as well as forage/bean meals of M. pruriens and C. ensiformis and their PSM, were extensively degraded during 24 h incubation, irrespective of the inoculum source (0.44 to 0.70 and 0.43 to 0.78 g/g of organic matter (OM) for ARDOM, respectively, and > 0.80 g/g for L-canavanine, > 0.76 TIU/TIU for TI, and > 0.95 g/g for Con A, for both legumes). Forage meal of L. leucocephala was considerably less degraded, with apparent ruminal degradabilities of 0.20 g/g OM and 0.35 g/g OM after 24 h incubation with Belgian or Cuban sheep inoculum, respectively. This could - at least partially - be related to L-mimosine, present in L. leucocephala, which was hardly degraded in the Belgian incubation, while a more extensive ruminal breakdown was observed under the Cuban conditions (0.05 g/g PSM vs. 0.78 g/g PSM, respectively). The negative effect of L-mimosine on OM degradability was supported in an additional in vitro experiment with straw and inoculum from Belgian sheep, as ruminal degradation of straw was 31% lower when pure L-mimosine was supplemented.

Encapsulated nitrate replacing soybean meal in diets with and without monensin on in vitro ruminal fermentation

This study assessed the association between encapsulated nitrate product (ENP) and monensin (MON) to mitigate enteric methane (CH4) in vitro and possible effects on ruminal degradability, enteric fermentation characteristics, and microbial populations. Six treatments were used in randomized complete design in a 2×3 factorial arrangement with two levels of MON (0 and 2.08 mg/mL of buffered rumen fluid) and three levels of ENP (0, 1.5 and 3.0%). The substrate consisted of 50% Tifton-85 hay and 50% concentrate mixture (ground corn and soybean meal). ENP replaced soybean meal to achieve isonitrogenous diets (15% CP). No ENP×MON interaction was observed for any measured variable (P > 0.05) except for the relative abundance of F. succinogenes (P = 0.02) that linearly increased in diets with MON when ENP was added. The ENP addition decreased CH4 production (P < 0.01) without affecting (P > 0.05) truly degraded organic matter nor the relative abundance of methanogens. Hydrogen production was reduced with MON (P = 0.04) and linearly decreased with ENP inclusion (P = 0.02). We concluded that use of nitrate is a viable strategy for CH4 reduction, however, no additive effect of ENP and MON was observed for mitigating CH4 production.

Ruminal Microbiome Manipulation to Improve Fermentation Efficiency in Ruminants

The rumen is an integrated dynamic microbial ecosystem composed of enormous populations of bacteria, protozoa, fungi, archaea, and bacteriophages. These microbes ferment feed organic matter consumed by ruminants to produce beneficial products such as microbial biomass and short-chain fatty acids, which form the major metabolic fuels for ruminants. The fermentation process also involves inefficient end product formation for both host animals and the environment, such as ammonia, methane, and carbon dioxide production. In typical conditions of ruminal fermentation, microbiota does not produce an optimal mixture of enzymes to maximize plant cell wall degradation or synthesize maximum microbial protein. Well-functioning rumen can be achieved through microbial manipulation by alteration of rumen microbiome composition to enhance specific beneficial fermentation pathways while minimizing or altering inefficient fermentation pathways. Therefore, manipulating ruminal fermentation is useful to improve feed conversion efficiency, animal productivity, and product quality. Understanding rumen microbial diversity and dynamics is crucial to maximize animal production efficiency and mitigate the emission of greenhouse gases from ruminants. This chapter discusses genetic and nongenetic rumen manipulation methods to achieve better rumen microbial fermentation including improvement of fibrolytic activity, inhibition of methanogenesis, prevention of acidosis, and balancing rumen ammonia concentration for optimal microbial protein synthesis.

Examining the Variables Leading to Apparent Incongruity between Antimethanogenic Potential of Tannins and Their Observed Effects in Ruminants—A Review

In recent years, several secondary plant metabolites have been identified that possess antimethanogenic properties. Tannin-rich forages have the potential to reduce methane emissions in ruminants while also increasing their nutrient use efficiency and promoting overall animal health. However, results have been highly inconclusive to date, with their antimethanogenic potential and effects on both animal performance and nutrition being highly variable even within a plant species. This variability is attributed to the structural characteristics of the tannins, many of which have been linked to an increased antimethanogenic potential. However, these characteristics are seldom considered in ruminant nutrition studies—often because the analytical techniques are inadequate to identify tannin structure and the focus is mostly on total tannin concentrations. Hence, in this article, we (i) review previous research that illustrate the variability of the antimethanogenic potential of forages; (ii) identify the source of inconsistencies behind these results; and (iii) discuss how these could be optimized to generate comparable and repeatable results. By adhering to this roadmap, we propose that there are clear links between plant metabolome and physiology and their antimethanogenic potential that can be established with the ultimate goal of improving the sustainable intensification of livestock.

Effect of replacing corn grains with date palm kernels on ruminal fermentation, feed degradability, and methane production under different initial in vitro pH conditions

Date kernels (DK) are cheap by-products rich in energy and phenolic compounds. It can be used as an alternative to the conventional sources of energy in ruminant diets while reducing methane (CH₄) production. Using a semi-automated gas production (GP) system, the initial pH of buffered rumen liquor was adjusted to 5.5 and 6.8. Five experimental diets were evaluated, control (0% DK), and DK₂₅, DK₅₀, DK_75, and DK₁₀₀ presented 25, 50, 75, and 100% replacement of maize by DK, respectively. Of the 16 phenolic compounds detected in DK, protocatechuic, p-hydroxybenzoic and catechin were the most abundant. At pH 6.8, the control diet recorded higher (p < 0.05) GP values throughout the first 12 h incubation than all other DK diets, while at 5.5 pH, DK₅₀ displayed the highest (p < 0.05) GP at 3 and 6 h compared to all other diets. At either pH conditions, all DK diets reduced (p < 0.05) CH₄ compared to the control without affecting protozoal counts. At 5.5 pH, DK diets showed enhanced (p < 0.05) nutrients degradability compared to control. DK modified (P < 0.05) the fermentation patterns toward more propionate than the control under either pH conditions. Substitution of maize by 50% DK was highly recommended in ruminant diets.

Replacing maize with low tannin sorghum grains: lamb growth performance, microbial protein synthesis and enteric methane production

Context Sorghum (Sorghum bicolor (L.) Moench) grain with low tannin content may be suitable as an alternative to maize (Zea mays L.) grain in ruminant diets in terms of input costs and drought tolerance, and effects on growth performance and mitigation of methane (CH4) emissions. Aims The study aimed to evaluate the effects of substitution of maize with sorghum grain at different rates on ruminal microbial protein synthesis, CH4 formation and liveweight gain in growing ruminants. Methods Twenty-five Santa Inês lambs (bodyweight 19.0 ± 1.5 kg) were randomly divided into five dietary treatments. Control diet components (on a dry matter basis) were Tifton-85 hay (400 g/kg), maize (405 g/kg), soybean meal (165 g/kg) and commercial mineral supplement (30 g/kg). Sorghum diets comprised the basal diet with the maize grain proportionately substituted with sorghum grain at 25%, 50%, 75% and 100% (diets S25–S100). Lamb feed intake, growth performance, nutrient digestibility, nitrogen balance, microbial protein synthesis and CH4 emission were measured during an experimental period of 70 days. Key results Negligible variations of chemical composition were observed among the experimental diets, although numerical increases in condensed tannins were observed with increasing levels of sorghum replacement. There was no significant effect of level of sorghum inclusion on feed intake. Partial substitution of maize with sorghum grain increased lamb average daily gain linearly (P = 0.02) and quadratically (P = 0.002) compared with diets based on either grain alone, with the S50 lambs having the highest values. A linear decrease in dry matter digestibility (P = 0.02), organic matter (P = 0.02) and acid detergent fibre (P = 0.002) was observed for lambs receiving sorghum diets compared with the control. A significant linear (P = 0.023) effect was observed for retained nitrogen (g/day), with lambs fed S25 and S50 having higher values than those in other treatments. All partially substituted diets (S25, S50 and S75) reduced CH4 per unit bodyweight gain in a linear trend (P = 0.03), by 35%, 29% and 33%, respectively, and tended to increase (linear effect, P = 0.09) the calculated amounts of absorbed microbial protein compared with the control diet. Conclusions Low tannin sorghum grains can replace maize grains by up to 75% to maximise ruminal microbial biomass production for optimal lamb growth performance and reduced CH4 emission. Implications Animal productivity can be enhanced while mitigating the environmental impact of livestock production through the partial substitution of maize by low tannin sorghum grains in ruminant diets.

Nutritional Quality, Voluntary Intake and Enteric Methane Emissions of Diets Based on Novel Cayman Grass and Its Associations With Two Leucaena Shrub Legumes

Methane (CH4) emissions from enteric fermentation in cattle are an important source of greenhouse gases, accounting for about 40% of all agricultural emissions. Diet quality plays a fundamental role in determining the magnitude of CH4 emissions. Specifically, the inclusion of feeds with high digestibility and nutritional value have been reported to be a viable option for reducing CH4 emissions and, simultaneously, increase animal productivity. The present study aimed to evaluate the effect of the nutritional composition and voluntary intake of diets based on tropical forages upon CH4 emissions from zebu steers. Five treatments (diets) were evaluated: Cay1: Urochloa hybrid cv. Cayman (harvested after 65 days of regrowth: low quality); Cay2: cv. Cayman harvested after 45 days of regrowth; CayLl: cv. Cayman + Leucaena leucocephala; CayLd: cv. Cayman + Leucaena diversifolia; Hay: Dichantium aristatum hay as a comparator of common naturalized pasture. For each diet representing different levels of intensification (naturalized pasture, improved pasture, and silvopastoral systems), CH4 emissions were measured using the polytunnel technique with four zebu steers housed in individual chambers. The CH4 accumulated was monitored using an infrared multigas analyzer, and the voluntary forage intake of each animal was calculated. Dry matter intake (DMI, % of body weight) ranged between 0.77 and 2.94 among diets offered. Emissions of CH4 per kg of DMI were significantly higher (P < 0.0001) in Cay1 (60.4 g), compared to other treatments. Diets that included Leucaena forage legumes had generally higher crude protein contents and higher DMI. Cay1 and Hay which had low protein content and digestibility had a higher CH4 emission intensity (per unit live weight gain) compared to Cay2, CayLl and CayLd. Our results suggest that grass consumed after a regrowth period of 45 days results in lower CH4 emissions intensities compared to those observed following a regrowth period of 65 days. Diets with Leucaena inclusion showed advantages in nutrient intake that are reflected in greater live weight gains of cattle. Consequently, the intensity of the emissions generated in the legume-based systems were lower suggesting that they are a good option for achieving the emission reduction goals of sustainable tropical cattle production.

Agronomic and qualitative characterization of multi-cut berseem clover (Trifolium alexandrinum L.) cultivars

BACKGROUND

Berseem clover is the main forage crop grown in Mediterranean regions. There are plenty of cultivars that possess variability in their productivity and quality among the different cuts. Therefore, accurate agronomic and qualitative characterization is crucial for selecting the most promising cultivars for breeding and feeding purposes. In the present study, the agronomic characteristics, ruminal degradability and fermentation measures of five cuts of the five most prominent Egyptian beseem clover cultivars (Helaly, Serw, Giza6, Gemmeza1 and Sakha4) were evaluated.

RESULTS

The Giza6 cultivar produced a significantly higher fresh yield and high whole plant dry matter content on the 3rd cut. Giza6 was among the superior cultivars in crude protein content and had the highest values of gas production at the 3rd cut, and ruminal degraded acid detergent fiber and propionate concentrations at the 2nd cut, at the same time as presenting the lowest ammonia concentrations at the 3rd and 5th cuts. Overall, the 3rd cut produced significantly higher fresh yield across all cultivars, except for Sakha4. The 3rd cut also produced a higher leaf to stem ratio compared to the 4th and 5th cuts. The 1st three cuts had higher degraded neutral detergent fiber than the 4th and 5th cuts. The 1st cut was characterized by low propionate concentration in the Helaly and Gemmeza1 cultivars compared to the other cuts.

CONCLUSION

Expanded production of the high-yielding, high-quality cultivar Giza6 is recommended. When harvesting, three cuts is optimal for berseem clover cultivation for breeding and feeding programs. © 2020 Society of Chemical Industry.