Diurnal variation in ciliate protozoa in the rumen of black buck (Antilope cervicapra) fed green forage

Effects of Dietary Inclusion of Sericea Lespedeza Hay on Feed Intake, Digestion, Nutrient Utilization, Growth Performance, and Ruminal Fermentation and Methane Emission of Alpine Doelings and Katahdin Ewe Lambs

Twenty-four Alpine doelings, initial 25.3 ± 0.55 kg body weight (BW) and 10.4 ± 0.11 mo of age, and 24 Katahdin ewe lambs, 28.3 ± 1.02 kg BW and 9.6 ± 0.04 mo of age, were used to determine effects of dietary inclusion of Sericea lespedeza (Lespedeza cuneata) hay on feed intake, digestion, growth performance, energy metabolism, and ruminal fermentation and methane emission. There were four periods, the first three 42 days in length and the fourth 47 days. Diets consumed ad libitum contained 75% coarsely ground hay with alfalfa (ALF), a 1:1 mixture of ALF and LES (ALF+LES), and LES (10.0% condensed tannins; CT). The intake of dry matter (DM) tended to be greater (p = 0.063) for Katahdin than for Alpine (4.14 vs. 3.84% BW; SEM = 0.110). The dry matter intake was similar among the diets (3.97, 4.10, and 3.89% BW for ALF, ALF+LES, and LES, respectively; SEM = 0.134). The digestion of organic matter (75.3, 69.3, and 65.5%; SEM = 0.86), neutral detergent fiber (61.7, 50.5, and 41.4%; SEM = 1.49), and nitrogen (78.8, 66.9, and 50.8% for ALF, ALF+LES, and LES, respectively; SEM = 0.92) decreased as the dietary concentration of lespedeza increased (p < 0.05). However, there was an interaction (p < 0.05) between the breed and diet in nitrogen digestion, with a greater value for goats vs. sheep with LES (54.4 vs. 47.3%; SEM = 1.30). The digested nitrogen intake decreased markedly with the increasing quantity of lespedeza (38.0, 27.5, and 15.7 g/day for ALF, ALF+LES, and LES, respectively; SEM = 1.26). The average daily gain was greater for Katahdin than for Alpine (p < 0.001; 180 vs. 88 g, SEM = 5.0) and ranked (p < 0.05) ALF > ALF+LES > LES (159, 132, and 111 g, respectively; SEM = 6.1). The ruminal methane emission differed (p < 0.05) between animal types in MJ/day (1.17 and 1.44), kJ/g DM intake (1.39 and 1.23), and kJ/g ADG (18.1 and 9.8 for Alpine and Katahdin, respectively). Regardless of the period and animal type, diet did not impact methane emission in MJ/day or relative to DM intake, BW, or ADG (p > 0.05). The digestible and metabolizable energy intakes, heat production, and retained energy were not affected by diet (p > 0.05). In conclusion, future research should consider the marked potential effect of CT of forages such as lespedeza on nitrogen digestion and associated effects on protein status and other conditions that may be impacted.

Comparison of enteric methane yield and diversity of ruminal methanogens in cattle and buffaloes fed on the same diet

An in vivo study was conducted to compare the enteric methane emissions and diversity of ruminal methanogens in cattle and buffaloes kept in the same environment and fed on the same diet. Six cattle and six buffaloes were fed on a similar diet comprising Napier (Pennisetum purpureum) green grass and concentrate in 70:30. After 90 days of feeding, the daily enteric methane emissions were quantified by using the SF6 technique and ruminal fluid samples from animals were collected for the diversity analysis. The daily enteric methane emissions were significantly greater in cattle as compared to buffaloes; however, methane yields were not different between the two species. Methanogens were ranked at different taxonomic levels against the Rumen and Intestinal Methanogen-Database. The archaeal communities in both host species were dominated by the phylum Euryarchaeota; however, Crenarchaeota represented <1% of the total archaea. Methanogens affiliated with Methanobacteriales were most prominent and their proportion did not differ between the two hosts. Methanomicrobiales and Methanomassillicoccales constituted the second largest group of methanogens in cattle and buffaloes, respectively. Methanocellales (Methanocella arvoryza) were exclusively detected in the buffaloes. At the species level, Methanobrevibacter gottschalkii had the highest abundance (55-57%) in both the host species. The relative abundance of Methanobrevibacter wolinii between the two hosts differed significantly. Methanosarcinales, the acetoclastic methanogens were significantly greater in cattle than the buffaloes. It is concluded that the ruminal methane yield in cattle and buffaloes fed on the same diet did not differ. With the diet used in this study, there was a limited influence (<3.5%) of the host on the structure of the ruminal archaea community at the species level. Therefore, the methane mitigation strategies developed in either of the hosts should be effective in the other. Further studies are warranted to reveal the conjunctive effect of diet and geographical locations with the host on ruminal archaea community composition.

Validating the Use of Bovine Buccal Sampling as a Proxy for the Rumen Microbiota by Using a Time Course and Random Forest Classification Approach

Analysis of the cow microbiome, as well as host genetic influences on the establishment and colonization of the rumen microbiota, is critical for development of strategies to manipulate ruminal function toward more efficient and environmentally friendly milk production. To this end, the development and validation of noninvasive methods to sample the rumen microbiota at a large scale are required. In this study, we further optimized the analysis of buccal swab samples as a proxy for direct bacterial samples of the rumen of dairy cows. To identify an optimal time for sampling, we collected buccal swab and rumen samples at six different time points relative to animal feeding. We then evaluated several biases in these samples using a machine learning classifier (random forest) to select taxa that discriminate between buccal swab and rumen samples. Differences in the inverse Simpson's diversity, Shannon's evenness, and Bray-Curtis dissimilarities between methods were significantly less apparent when sampling was performed prior to morning feeding (P < 0.05), suggesting that this time point was optimal for representative sampling. In addition, the random forest classifier was able to accurately identify nonrumen taxa, including 10 oral and putative feed-associated taxa. Two highly prevalent (>60%) taxa in buccal and rumen samples had significant variance in relative abundances between sampling methods but could be qualitatively assessed via regular buccal swab sampling. This work not only provides new insights into the oral community of ruminants but also further validates and refines buccal swabbing as a method to assess the rumen bacterial in large herds.IMPORTANCE The gastrointestinal tracts of ruminants harbor a diverse microbial community that coevolved symbiotically with the host, influencing its nutrition, health, and performance. While the influence of environmental factors on rumen microbes is well documented, the process by which host genetics influences the establishment and colonization of the rumen microbiota still needs to be elucidated. This knowledge gap is due largely to our inability to easily sample the rumen microbiota. There are three common methods for rumen sampling but all of them present at least one disadvantage, including animal welfare, sample quality, labor, and scalability. The development and validation of noninvasive methods, such as buccal swabbing, for large-scale rumen sampling is needed to support studies that require large sample sizes to generate reliable results. The validation of buccal swabbing will also support the development of molecular tools for the early diagnosis of metabolic disorders associated with microbial changes in large herds.

Effect of silkworm (Bombyx mori) pupae oil supplementation on enteric methane emission and methanogens diversity in sheep

In vitro and in vivo studies were conducted to examine the effect of silkworm pupae oil on methane (CH₄) emission and methanogens diversity. Five graded levels (2, 4, 6, 8 and 10%) of silkworm pupae oil were tested in vitro. Eighteen Mandya adult sheep were divided into three groups. All the animals were fed on similar basal diet except the oil supplementation in test groups. Oil level for supplementation was decided on the basis of in vitro study. In vitro study indicated a reduction of 22% in CH₄ production with 2% oil supplementation. Animals in test groups were supplemented with oil (2%) either daily (CON) or intermittently (INT) on every alternate week for all the seven days. A significant reduction of 17-20% in enteric CH₄ emission (g/d) was achieved due to oil supplementation in sheep. However, No variation was established between test groups CON and INT. In present study, Methanobrevibacter was major genus contributed ∼90% of the total rumen methanogens; whilst Methanobrevibacter gottschalkii was the most abundant methanogens species. Abundance of Methanobrevibacter ruminantium was affected with the oil supplementation. It can be concluded that the silkworm pupae oil at 2% can decrease CH₄ emission by 15-20%.

In vitro evaluation of graded level of Silkworm pupae (Bombyx mori) oil on methane production, fermentation characteristics, and protozoal populations

Aim

The present study was undertaken to evaluate the effect of variable levels of silkworm pupae oil and roughage: concentrate ratio on in vitro methane production, fermentation characteristics, and rumen protozoa population.

Materials and Methods

In vitro gas production study (24 h) was performed with graded levels of silkworm pupae oil, namely, 0.5, 1, 2, 4, and 5% of the basal diet and four variable dietary regimes consisting roughage and concentrate in different proportions (70:30, 60:40, 50:50, and 40:60). At the end of incubation, gas samples were analyzed for methane, while fermented rumen liquor was used for protozoa enumeration. A separate set of incubations was carried out for the determination of in vitro dry matter digestibility.

Results

Results from the in vitro studies revealed no adverse impact of the silkworm pupae oil supplementation up to 2% level on total gas production. However, supplementation beyond 2% has shown a reduction in total gas production. Incubation with variable levels (0.5-5%) of silkworm pupae oil with different dietary regimes indicated negligible (3-5%) to a substantial reduction (25-30%) on methane production. A graded decrement in methane production was recorded with increasing levels of silkworm pupae oil. Similarly, the protozoal populations were decreased from 10 to 51.5% with graded levels of silkworm pupae oil in different dietary regimes as studies did not reveal any significant (p>0.05) variation between 2 and 4% of oil supplementation.

Conclusion

The silkworm pupae oil supplementation at 2% level decreases methane production by 12-15% without any adverse impact on feed fermentation. Oil supplementation may have a more pronounced effect on methane reduction if added to high roughage diet at in vitro conditions. However, in vivo, studies in ruminants are warranted to confirm the methane reduction with silkworm pupae oil supplementation.

Efficacy of dietary supplementation of Tinospora cordifolia stem in prevention of sub-acute lactic acidosis in goats

Present study was undertaken to investigate the effect of dietary supplementation of T. cordifolia for reducing the risk of lactic acidosis in goats. Jamnapari goats (10) were divided into two groups. Goats of treatment group were fed T. cordifolia stem powder @ 2% in concentrate feed for 14 days. Control animals were fed equal amount of concentrate without T. cordifolia powder. After 14 days, goats were fed overnight soaked wheat grain @ 50 g/kg body weight to induce lactic acidosis. Samples of rumen fluid at 0 and 12 h, and blood were collected on 0, 12 and 36 h of feeding of grain. Lactic acid concentration, total protozoa count and pH of rumen fluid were used as markers to assess the ameliorative potential of T. cordifolia stem. Mean lactic acid concentration, protozoa count and ammonia nitrogen of rumen fluid of T. cordifolia supplemented goats were 3.47±0.33 mg/dL, 1820.70±121.36 × 103/mL, and 2.71±0.09 mg/dL respectively on 12 h of induction of lactic acidosis. The concentrations of these parameters in control goats were 5.01±0.22 mg/dL, 1168.96±75.36 × 103/mL and 1.77±0.40 mg/dL respectively. These findings provided evidence that supplementation of T. cordifolia stem can prevent lactic acidosis in goats.

Nutritional evaluation of sugarcane (Saccharum officinarum) trash as dry fodder source for cattle

The present experiment was conducted in two phases. In the first phase, sugarcane (Saccharum officinarum) trash (ST), rice (Oryza sativa) straw (RS) and finger millet (Eleusine corocana) straw (FMS), and their respective diets comprising 70% dry ST, 20% paragrass (Brachiara mutica) and 10% concentrate mixture were evaluated by in vitro gas production techique (IVGPT). The gas production, DMD and OMD were less in ST followed by RS and FMS. Significantly lower acetate, propionate, butyrate, total volatile fatty acids and A:P was recorded in ST followed by RS and FMS. Similar trend was noticed in case of total mixed rations (TMR). In the second phase, ST based total mixed ration was evaluated against conventional FMS based ration. Crossbred cattle (10; average BW 318±19 kg) were divided into 2 groups. Group I was offered TMR comprising 70% FMS whereas in group II, FMS was replaced by ST. The digestibility of DM, OM and NFE was lower in cattle fed ST as compared to FMS. Digestible CP of the diets remained same in both groups, however, TDN value was more in case of FMS based TMR. Ca, P, Zn absorption was found to be similar in both the groups. However, Mg and Cu absorption was more in ST based TMR. We can conclude that overall nutritive value of ST was lower than FMS, hence, ST is recommended for feeding as an alternate dry fodder under scarcity situations.

Effects of lespedeza condensed tannins alone or with monensin, soybean oil, and coconut oil on feed intake, growth, digestion, ruminal methane emission, and heat energy by yearling Alpine doelings

Fifty-four Alpine doelings (initial BW and age of 31.7 ± 0.38 kg and 306 ± 1.9 d, respectively) were allocated to nine treatments individually fed for ad libitum intake of 25% concentrate and 75% forage diets (DM basis). Alfalfa was the forage in the control diet. Other diets contained Sericea lespedeza as the forage, with 1.25% DM of quebracho extract included in the concentrate fraction for a dietary condensed tannin level of 8.4%. Lespedeza treatments were no additive (L) and inclusion of monensin (I) at 22 mg/kg DM (L-I), soybean oil at 3% (L-S), coconut oil at 3% (L-N), I and 3% soybean oil (L-I-S), I and 3% coconut oil (L-I-N), 1.5% soybean oil and 1.5% coconut oil (L-S-N), and I, 1.5% soybean oil, and 1.5% coconut oil (L-I-S-N). The experiment was 12 wk with two 6-wk periods. Gas exchange was determined in weeks 6 and 12, and other measures occurred in weeks 5 and 11. The control diet offered averaged 2.67% nitrogen, 43.8% neutral detergent fiber, and 8.8% acid detergent lignin, and the L diet offered averaged 2.03% nitrogen, 42.8% neutral detergent fiber, and 13.2% acid detergent lignin. There were no treatment × period interactions for digestibilities (P ≥ 0.770) or methane emission (P ≥ 0.324). There were differences (P < 0.001) between the control treatment and diets with lespedeza in intake of DM (1.46, 1.23, 1.30, 1.18, 1.32, 1.10, 1.02, 1.20, and 1.01 kg/d; SEM = 0.059), digestibility of OM (57.4%, 50.9%, 51.8%, 52.7%, 50.3%, 52.1%, 52.1%, 51.9%, and 49.8%; SEM = 1.42), and digestibility of nitrogen (59.1%, 31.2%, 32.5%, 37.1%, 31.6%, 38.3%, 30.4%, 38.4%, and 34.1% for control, L, L-I, L-S, L-N, L-I-S, L-I-N, L-S-N, and L-I-S-N, respectively; SEM = 2.21). Ruminal methane emission was less (P < 0.001) for diets with lespedeza than for the control in MJ/d (1.36, 0.76, 0.84, 0.71, 0.71, 0.66, 0.65, 0.68, and 0.68; SEM = 0.048) and relative to intake of gross energy (5.92%, 3.27%, 3.49%, 3.19%, 2.84%, 2.91%, 3.20%, 3.20%, and 3.27%; SEM = 0.165) and digestible energy (11.19%, 6.98%, 7.40%, 6.38%, 5.90%, 5.69%, 6.37%, 6.38%, and 6.70% for control, L, L-I, L-S, L-N, L-I-S, L-I-N, L-S-N, and L-I-S-N, respectively; SEM = 0.400). In conclusion, the magnitude of effect of condensed tannins from lespedeza and quebracho extract on ruminal methane emission by Alpine doelings did not diminish over time and was not markedly influenced by dietary inclusion of monensin, soybean oil, or coconut oil.

Potential of guava leaves for mitigating methane emissions and modulating ruminal fermentation characteristics and nutrient degradability

Guava leaves (Psidium guajava, GL), a high-phenolic- and flavonoid-containing plant resource capable of substituting the high-quality forage, may help in mitigating ruminal methane (CH₄) emission without adverse impact on nutrient degradability if supplemented at an appropriate level. In order to test this hypothesis, rumen fermentation, CH₄ production, and nutrient degradability of GL either solely or as a substitute of berseem hay (Trifolium alexandrinum, BH) were evaluated in a diet containing 50:50 concentrate to roughage. Five different levels of GL (0, 12.5, 25, 37.5, and 50%) were tested in vitro after 24 h incubation using a semi-automated gas production (GP) system. The current findings indicated that merely the presence of GL resulted in significantly lower values for cumulative GP (P < 0.001), CH₄ emission (P < 0.05), truly degraded dry matter (TDDM; P < 0.001), truly degraded organic matter (TDOM; P < 0.001), and ammonia nitrogen (NH₃-N) concentration (P < 0.001); however, pH (P < 0.001) and partitioning factor (P < 0.001) were higher. The total and individual volatile fatty acid (VFA) concentrations were drastically declined with GL as compared to BH (P < 0.05). A negative linear correlation was recorded between the levels of GL and GP including CH₄ production (P < 0.05). The addition of GL up to 25% did not pose any negative effect on both TDDM and TDOM values along with NH₃-N concentration. In addition, the inclusion of GL up to 25% did not affect the total or individual VFA concentration. Conclusively, in a medium concentrate diet, use of 25% GL and 25% BH in animal diet could be a promising alternative for mitigating the CH₄ production without any deleterious effect on nutrient degradability.

Effect of high and low roughage total mixed ration diets on rumen metabolites and enzymatic profiles in crossbred cattle and buffaloes

Aim::

A comparative study was conducted on crossbred cattle and buffaloes to investigate the effect of feeding high and low roughage total mixed ration (TMR) diets on rumen metabolites and enzymatic profiles.

Materials and Methods::

Three rumen-fistulated crossbred cattle and buffalo were randomly assigned as per 3×3 switch over design for 21-days. Three TMR diets consisting of concentrate mixture, wheat straw and green maize fodder in the ratios of (T₁) 60:20:20, (T₂) 40:30:30, and (T₃) 20:40:40, respectively, were fed to the animals ad libitum. Rumen liquor samples were collected at 0, 2, 4, 6, and 8 h post feeding for the estimation of rumen biochemical parameters on 2 consecutive days in each trial.

Results::

The lactic acid concentration and pH value were comparable in both species and treatments. Feed intake (99.77±2.51 g/kg body weight), ruminal ammonia nitrogen, and total nitrogen were significantly (p<0.05) higher in buffalo and in treatment group fed with high concentrate diet. Production of total volatile fatty acids (VFAs) was non-significant (p>0.05) among treatments and significantly (p<0.05) greater in crossbred cattle than buffaloes. Molar proportions of individual VFAs propionate (C3), propionate:butyrate (C3:C4), and (acetate+butyrate):propionate ([C2+C4]:C3) ratio in both crossbred cattle and buffalo were not affected by high or low roughage diet, but percentage of acetate and butyrate varied significantly (p<0.05) among treatment groups. Activities of microbial enzymes were comparable among species and different treatment groups. A total number of rumen protozoa were significantly (p<0.05) higher in crossbred cattle than buffaloes along with significantly (p<0.05) higher population in animal fed with high concentrate diet (T₁).

Conclusion::

Rumen microbial population and fermentation depend on constituents of the treatment diet. However, microbial enzyme activity remains similar among species and different treatments. High concentrate diet increases number of rumen protozoa, and the number is higher in crossbred cattle than buffaloes.

Changes in rumen protozoal community by condensed tannin fractions of different molecular weights from a Leucaena leucocephala hybrid in vitro

AIMS

To evaluate the effects of condensed tannins (CTs) fractions of differing molecular weights (MWs) from a Leucaena leucocephala hybrid-Rendang on the rumen protozoal community in vitro.

METHODS AND RESULTS

The effects of unfractionated CTs (F0) and CT fractions of different MWs (F1 > F2 > F3 > F4 > F5) on protozoal population and community were evaluated in vitro using rumen microbes and ground guinea grass as the substrate. Higher-MW CT fractions F1 and F2 significantly (P < 0·05) decrease the number of ciliate protozoa. The real-time PCR analysis showed that the total protozoa was significantly (P < 0·05) lower in F0 and all CTs with fractions F1 and F2 having the lowest value. High-throughput sequencing of the partial 18S rRNA gene showed that the genus Entodinium significantly (P < 0·05) decreased with increasing MWs of CT, whereas Anoplodinium-Diplodinium were significantly (P < 0·05) increased. Inclusion of the highest MW CT fraction F1 decreased the relative abundance of the minor genera such as Eudiplodinium and Polyplastron compared to the control and CT fractions F2-F5.

CONCLUSION

CTs of differing MWs could reduce and alter the rumen protozoa population in vitro. This effect was more pronounced for higher-MW CTs.

SIGNIFICANCE AND IMPACT OF THE STUDY

The high MW CTs should be considered as a feed supplement in the ruminant diet to reduce the protozoal population which are known to be associated with methanogens as a means to mitigate methane production in the rumen.

Effects of different vegetable oils on rumen fermentation and conjugated linoleic acid concentration in vitro

Aim:

The objective of this study was to investigate the effect of different vegetable oils on rumen fermentation and concentrations of beneficial cis-9 trans-11 C18:2 conjugated linoleic acid (CLA) and trans-11 C18:1 fatty acid (FA) in the rumen fluid in an in vitro condition.

Materials and Methods:

Six vegetable oils including sunflower, soybean, sesame, rice bran, groundnut, and mustard oils were used at three dose levels (0%, 3% and 4% of substrate dry matter [DM] basis) in three replicates for each treatment in a completely randomized design using 6 × 3 factorial arrangement. Rumen fluid for microbial culture was collected from four goats fed on a diet of concentrate mixture and berseem hay at a ratio of 60:40 on DM basis. The in vitro fermentation was performed in 100 ml conical flakes containing 50 ml of culture media and 0.5 g of substrates containing 0%, 3% and 4% vegetable oils.

Results:

Oils supplementation did not affect (p>0.05) in vitro DM digestibility, and concentrations of total volatile FAs and ammonia-N. Sunflower oil and soybean oil decreased (p<0.05) protozoal numbers with increasing levels of oils. Other oils had less pronounced effect (p>0.05) on protozoal numbers. Both trans-11 C18:1 FA and cis-9, trans-11 CLA concentrations were increased (p<0.05) by sunflower and soybean oil supplementation at 4% level with the highest concentration observed for sunflower oil. The addition of other oils did not significantly (p>0.05) increase the trans-11 C18:1 FA and cis-9, trans-11 CLA concentrations as compared to the control. The concentrations of stearic, oleic, linoleic, and linolenic acids were not altered (p>0.05) due to the addition of any vegetable oils.

Conclusion:

Supplementation of sunflower and soybean oils enhanced beneficial trans-11 C18:1 FA and cis-9, trans-11 CLA concentrations in rumen fluid, while sesame, rice bran, groundnut, and mustard oils were ineffective in this study.

Influence of supplementation of tropical plant feed additives on in vitro rumen fermentation and methanogenesis

Tropical plants rich in secondary metabolites have the potential to modulate rumen fermentation for more efficient food production with reduced environmental impact. In the present study after extensive screening, three tropical tree leaves (Bahunia variegata, Psidium guajava and Cannabis indica) and three herbs (Cinnamomum zeylanicum, Trachyspermum ammi and Cinnamomum tamala) were selected to evaluate their effect on buffalo rumen fermentation. Total gas production, substrate degradability, volatile fatty acid pattern and enzyme activities were not affected by any of the plants tested in this study. However, methane production was lowered (P ≤ 0.05) due to inclusion of P. guajava leaves. Anti-methanogenic/anti-protozoal metabolites present in tropical plants seem to be better extracted by ethanol solvent and accordingly the best performing plant i.e. different levels of P. guajava extract was used for further evaluation. Both the methane inhibition and defaunating action of ethanol extract of P. guajava were found to be dose dependent. In conclusion, leaves of P. guajava appear to be a promising plant feed additive for decreasing methane production without affecting feed degradability in the rumen.

Fluorescence in situ hybridization probing of protozoal Entodinium spp. and their methanogenic colonizers in the rumen of cattle fed alfalfa hay or triticale straw

AIMS

To develop and test a fluorescence in situ hybridization (FISH) based technique and to identify and quantify simultaneously those methanogenic populations colonizing Entodinium spp. in the rumen of cows fed different forages.

METHODS AND RESULTS

New FISH probes targeting protozoal Entodinium spp. were designed and used together with FISH probes for methanogens in the cow rumen. The composition and relative abundance of methanogenic populations colonizing Entodinium simplex-, E. caudaum- and Entodinium furca-related populations were similar. Methanogens including Methanobrevibacter thaueri, Methanobrevibacter millerae and Methanobrevibacter smithii, and members of Methanomicrobium and Methanosphaera were generally the predominant colonizers of protozoa, regardless of the forage fed to cattle. Individual animals appeared to differ in which ruminal methanogenic populations colonized each of the individual Entodinium spp.

CONCLUSIONS

Simultaneous FISH probing is shown here to be a reliable and effective approach to investigate the dynamics of symbiotic relationships between ruminal protozoa and methanogens at a single cell level. Phylogenetically closely related Entodinium spp. were colonized by similar methanogenic populations regardless of the forage fed.

SIGNIFICANCE AND IMPACT OF THE STUDY

This is the first report of the methanogenic archaeal populations that specifically colonize Entodinium spp. as identified using simultaneous FISH probing.

Nutrient content, in vitro ruminal fermentation characteristics and methane reduction potential of tropical tannin-containing leaves

BACKGROUND

Plant tannins as rumen modifiers are better than chemicals or antibiotic-based modifiers since these compounds are natural products which are environmentally friendly and therefore have a better acceptance with regard to feed safety issues. Tropical plants containing phenols such as tannins were found to suppress or eliminate protozoa from the rumen and reduce methane and ammonia production. The screening of these plants is an important step in the identification of new compounds and feed additives which might contribute to mitigate rumen methanogenesis. The present study was carried out to determine the efficacy of tannins from tropical tree leaves for their methane reduction properties.

RESULTS

Activity of tannins, as represented by the increase in gas volume with the addition of polyethylene glycol (PEG)-6000 as a tannin binder (tannin bioassay) was highest in Ficus bengalensis (555%), followed by Azardirachta indica (78.5%). PEG addition did not alter (P > 0.05) methane percentage in Ficus racemosa, Glyricidia maculata, Leucena leucocephala, Morus alba and Semaroba glauca, confirming that tannins in these samples did not affect methanogenesis. The increase (P < 0.05) in protozoa population with PEG was maximal in Ficus religiosa (50), followed by Moringa oleifera (31.2), Azardirachta indica (29.9) and Semaroba glauca (27.5). There was no change (P > 0.05) in the protozoa population in Autocarpus integrifolia, Ficus bengalensis, Jatropha curcus, Morus alba and Sesbania grandiflora, demonstrating that methane reduction observed in these samples per se was not due to defaunation effect of the tannin. The increase in total volatile fatty acid concentration in samples with PEG ranged from 0.6% to > 70%. The highest increase (%) in NH(3)-N was recorded in Azardirachta indica (67.4), followed by Ficus mysoriensis (35.7) and Semaroba glauca (32.6) leaves, reflecting strong protein binding properties of tannin.

CONCLUSION

The results of our study established that in vitro methanogenesis was not essentially related to the density of protozoa population. Tropical tree leaves containing tannins such as Autocarpus integrifolia, Jatropha curcus and Sesbania grandiflora have the potential to suppress methanogenesis. Therefore tannins contained in these plants could be of interest in the development of new additives in ruminant nutrition.

Phenolic Composition, Fermentation Profile, Protozoa Population and Methane Production from Sheanut (Butryospermum Parkii) Byproducts In vitro

Sheanut cake (SNC), expeller (SNE) and solvent extractions (SNSE) samples were evaluated to determine their suitability in animal feeding. The CP content was highest in SNSE (16.2%) followed by SNE (14.7%) and SNC (11.6%). However, metabolizable energy (ME, MJ/kg) was maximum in SNC (8.2) followed by SNE (7.9) and SNSE (7.0). The tannin phenol content was about 7.0 per cent and mostly in the form of hydrolyzable tannin (HT), whereas condensed tannin (CT) was less than one per cent. The in vitro gas production profiles indicated similar y max (maximum potential of gas production) among the 3 by-products. However, the rate of degradation (k) was maximum in SNC followed by SNE and SNSE. The t(1/2) (time taken for reaching half asymptote) was lowest in SNC (14.4 h) followed by SNE (18.7 h) and SNSE (21.9 h). The increment in the in vitro gas volume (ml/200 mg DM) with PEG (polyethylene glycol)-6000 (as a tannin binder) addition was 12.0 in SNC, 9.6 in SNE and 11.0 in SNSE, respectively. The highest ratio of CH4 (ml) reduction per ml of the total gas, an indicator of the potential of tannin, was recorded in SNE (0.482) followed by SNC (0.301) and SNSE (0.261). There was significant (p<0.05) reduction in entodinia population and total protozoa population. Differential protozoa counts revealed that Entodinia populations increased to a greater extent than Holotricha when PEG was added. This is the first report on the antimethanogenic property of sheanut byproducts. It could be concluded that all the three forms of SN byproducts are medium source of protein and energy for ruminants. There is a great potential for SN by-products to be incorporated in ruminant feeding not only as a source of energy and protein, but also to protect the protein from rumen degradation and suppress enteric methanogenesis.

Effects of different fresh-cut forages and their hays on feed intake, digestibility, heat production, and ruminal methane emission by Boer x Spanish goats

Twenty-four yearling Boer × Spanish wethers were used to assess effects of different forages, either fresh (Exp. 1) or as hay (Exp. 2), on feed intake, digestibilities, heat production, and ruminal methane emission. Treatments were: 1) Sericea lespedeza (SER; Lespedeza cuneata), a legume high in condensed tannins (CT; 20% and 15% in fresh forage and hay, respectively), 2) SER supplemented with polyethylene glycol (SER-PEG; 25 g/d), 3) alfalfa (Medicago sativa), a legume low in CT (ALF), and 4) sorghum-sudangrass (Sorghum bicolor), a grass low in CT (GRASS). Experiments were 22 d, which included 16 d for acclimatization followed by a 6-d period for fecal and urine collection, and gas exchange measurement (last 2 d). Intake of OM was 867, 823, 694, and 691 g/d (SEM = 20.1) with fresh forage, and 806, 887, 681, and 607 g/d with hay for SER, SER-PEG, ALF, and GRASS, respectively (SEM = 46.6). Apparent total tract N digestion was greater for SER-PEG vs. SER (P < 0.001) with fresh forage (46.3%, 66.5%, 81.7%, and 73.2%; SEM = 1.71) and hay (49.7%, 71.4%, 65.4%, and 54.8% for SER, SER-PEG, ALF, and GRASS, respectively; SEM = 1.57). Intake of ME was similar among treatments with fresh forage (8.24, 8.06, 7.42, and 7.70 MJ/d; SEM = 0.434) and with hay was greater for SER-PEG than ALF (P < 0.03) and GRASS (P < 0.001) (8.63, 10.40, 8.15, and 6.74 MJ/d for SER, SER-PEG, ALF, and GRASS, respectively; SEM = 0.655). The number of ciliate protozoa in ruminal fluid was least for SER with fresh forage (P < 0.01) (9.8, 20.1, 21.0, and 33.6 × 10(5)/ml; SEM = 2.76) and hay (P < 0.02) (6.3, 11.4, 13.6, and 12.5 × 10(5)/ml for SER, SER-PEG, ALF, and GRASS, respectively; SEM = 1.43). Methane emission as a percentage of DE intake was lower (P < 0.01) for SER vs. ALF and GRASS with fresh forage (6.6, 8.3, 9.4, and 9.2%; SEM = 0.64) and hay (4.3, 4.9, 6.4, and 6.7% for SER, SER-PEG, ALF, and GRASS, respectively; SEM = 0.38). In summary, methane emission in this short-term experiment was similar between a legume and grass low in CT as fresh forage and hay. The CT in SER markedly decreased N digestibility and elicited a moderate decline in ruminal methane emission. Supplementation with PEG alleviated the effect of CT on N digestibility but not ruminal methane emission, presumably because of different modes of action. In conclusion, potential of using CT-containing forage as a means of decreasing ruminal methane emission requires further study, such as with longer feeding periods.

Effect of medicinal and aromatic plants on rumen fermentation, protozoa population and methanogenesis in vitro

The potential of tannins from 21 medicinal and aromatic plant leaves as antimethanogenic additives in ruminant feeds was investigated. The effect of tannin from these leaves on rumen fermentation parameters, protozoa population and methanogenesis was studied by incubating the samples [200 mg dry matter (DM)] without and with polyethylene glycol (PEG)-6000 (400 mg DM) as a tannin binder during 24-h incubation in the in vitro Hohenheim gas method. Based on the methane percentage estimated in the total gas produced, methane production in millilitre was calculated [methane volume (ml) = methane % × total gas produced (ml) in 24 h]. In the samples, crude protein and neutral detergent fibre (g/kg DM) ranged from 113 to 172 and from 352 to 444 respectively. The total phenol (TP; g/kg DM) content was highest in Terminalia chebula (274) followed by Hemigraphis colorata (71) and Sapindus laurifolia (51) respectively. In the remaining samples, it was <43 g/kg DM. Activity of tannins, as represented by the increase in gas volume on addition of PEG, ranged from 0 to 133%, with the highest being recorded in T. chebula. The per cent increase in methane on PEG addition was 0 for Ammi majus, Aristolochia indica, Cascabela thevetia, Ipomea nil and Lantana camara, illustrating that tannins present in these samples had no effect on methane concentration. The PEG addition increased the total protozoa count by >50% in A. indica and C. thevetica. One of the important findings of our study was that of the 21 samples screened, Entodinia population increased in 12 with PEG as compared to 7 where Holotricha increased, indicating higher susceptibility of Entodinia to tannin. There was no increase in the protozoa population with PEG when incubating Cardiospermum halicacabum, Clerodendrum inerme, Dioscorea floribunda, Nerium oleander and Selastras paniculatus, which strongly suggested that methane suppression recorded in these samples was not because of a defaunating effect of their tannins per se. The fermentation pattern reflected increased total volatile fatty acid (TVFA) concentration from 0 to 28.3% with PEG addition among the leaves. Our results confirmed further observations that methanogenesis in vitro is not essentially related to density of protozoa population. Secondly, medicinal and aromatic plants such as C. inerme, Gymnema sylvestre and Sapindus laurifolia containing tannins appear to have a potential to suppress in vitro methanogenesis.

Effect of some essential oils on in vitro methane emission

The objectives of this study were to characterise four essential oils (EO) chemically and to evaluate their effect on ruminal fermentation and methane emission in vitro. The investigated EO were isolated from Achillea santolina, Artemisia judaica, Schinus terebinthifolius and Mentha microphylla, and supplemented at four levels (0, 25, 50 and 75 microl) to 75 ml of buffered rumen fluid plus 0.5 g of substrate. The main components of the EO were piperitone (49.1%) and camphor (34.5%) in A. judaica, 16-dimethyl 15-cyclooactdaiene (60.5%) in A. santolina, piperitone oxide (46.7%) and cis-piperitone oxide (28%) in M. microphylla, and gamma-muurolene (45.3%) and alpha-thujene (16.0%) in S. terebinthifolius. The EO from A. santolina (at 25 and 50 j1), and all levels of A. judaica increased the gas production significantly, but S. terebinthifolius (at 50 and 75 microl), A. santolina (at 75 microl) and all levels of M. microphylla decreased the gas production significantly in comparison with the control. The highest levels of A. santolina and A. judaica, and all doses from M. microphylla EO inhibited the methane production along with a significant reduction in true degradation of dry matter and organic matter, protozoa count and NH3-N concentration. It is concluded that the evaluated EO have the potential to affect ruminal fermentation efficiency and the EO from M. microphylla could be a promising methane mitigating agent.

Effects of extracts of spices on rumen methanogenesis, enzyme activities and fermentation of feeds in vitro

BACKGROUND

An experiment was conducted to study the effects of boiling water, methanol and ethanol extracts (0, 0.25 and 0.50 mL) of seeds of Foeniculum vulgare (fennel), flower buds of Syzygium aromaticum (clove), bulbs of Allium sativum (garlic), bulbs of Allium cepa (onion) and roots of Zingiber officinalis (ginger) on rumen methanogenesis, fibrolytic enzyme activities and fermentation characteristics in vitro.

RESULTS

Ethanol and methanol extracts of fennel, clove and garlic at 0.50 mL and clove at 0.25 mL inhibited (P < 0.05) methane production. Carboxymethylcellulase activity was reduced (P < 0.05) by ethanol and methanol extracts (0.50 mL) of fennel and clove (0.25 and 0.50 mL). The extracts of clove reduced (0.25 and 0.50 mL) xylanase and acetylesterase activities, and the fennel extract (0.50 mL) reduced (P < 0.05) xylanase activity. However, the extracts of garlic (0.50 mL) increased (P < 0.05) acetylesterase activity. Concentrations of volatile fatty acids were reduced (P < 0.05) by the extracts of garlic and onion. The extracts of garlic caused a decrease (P < 0.05) in acetate:propionate ratio (A:P) at 0.50 mL, whereas A:P was increased (P < 0.05) by the inclusion of 0.50 mL extracts of clove. Methanol and ethanol extracts of clove decreased (P < 0.05) in vitro organic matter degradability. Extracts (0.50 mL) of clove decreased (P < 0.05) the numbers of total protozoa, small entodiniomorphs and holotrichs, whereas extracts of onion, ginger and garlic enhanced (P < 0.05) protozoal numbers (both entodiniomorphs and holotrichs).

CONCLUSION

Ethanol and methanol extracts of fennel and garlic have potential to inhibit rumen methanogenesis without adversely affecting rumen fermentation.

Effect of different feeding regimes on pre-weaning growth rumen fermentation and its influence on post-weaning performance of lambs

Influence of pre-weaning live weight on post-weaning growth performance was assessed on thirty-nine 15-day-old Indian native lambs, randomly fed in three equal groups until 180 days of age. During pre-weaning phase lambs were maintained under feeding regimen of grazing (C-0; Control), grazing and ad lib creep mixture supplementation (C-AL) or grazing, with ad lib creep mixture and milk replacer supplementation (C-ALMR). Lambs were allowed to suckle respective dam in morning and evening till 90 days of age, and fed ad lib green leaves of Ailanthus excelsa after grazing. After weaning all lambs were maintained on grazing and ad lib finisher concentrates supplementation. Pre-weaning performance of lambs in terms of weaning weight (17.2 kg), average daily gain (ADG; 154 g) and feed conversion ratio 3.73 was higher (p < 0.01) in C-ALMR lambs but total gain and ADG were similar among three groups during post-weaning phase. However, improved pre-weaning plane of nutrition and growth rate increased (p < 0.01) finishing weight (FW) of lambs in C-AL, 33 kg and C-ALMR, 32 kg. Dry matter intake was significantly (p < 0.01) higher in C-AL and C-ALMR lambs due to combined effect of feeding. Rumen pH was lowest (p = 0.049) in C-AL lambs. Rumen ciliate protozoa population (10(4)/ml) decreased in C-ALMR lambs (4.3) but increased in C-AL lambs (50.0) more so in C-0 Lambs (19.8). Concentrate feeding of C-AL lamb improved nutrient digestibility. Lambs of C-0 group consumed more DM during post-weaning phase that improved growth performance, while nutrient digestibility was not affected by pre-weaning nutrition. Thus, pre-weaning nutrition has significant influence on FW, however influence of milk replacer feeding on lamb growth need further studies.

Effect of inclusion of tree leaves in feed on nutrient utilization and rumen fermentation in sheep

The effect of inclusion of tree leaves in mustard (Brassica campestris) straw (MS) based complete feed blocks (CFB) on nutrient utilization and rumen fermentation was studied in adult male sheep. Four types of CFB diets (Roughage:Concentrate:Molasses, 70:25:5) were prepared. The compaction process increased bulk density (g/cm(3)) of MSB, MSNL, MSSL and MSAL by 2.9, 1.79, 2.40 and 2.26 times, respectively. The dry matter intake (g/day) was higher (P<0.05) in MSSL and MSAL than in MSB. Digestibility coefficients of crude protein and hemicellulose increased (P<0.05) due to inclusion of tree leaves, while digestibility of dry matter and organic matter showed small improvement. However, inclusion of tree leaves did not affect digestibility of neutral detergent fibre, cellulose and energy. The concentration of total volatile fatty acids in rumen was significantly higher in MSAL than in MSB or MSSL. Blood bio-chemical parameters were within the normal physiological range in all the groups.

Pre- and postweaning attributes in faunated and ciliate-free calves fed calf starter with or without fish meal

In a 2 x 2 factorial design, 24 newborn, crossbred (Bos indicus x Bos taurus) calves were distributed in 4 equal groups involving dietary treatments of prestarter diets with (FM) or without fish meal (NFM) in a faunated (F) or ciliate-free (D) ruminal environment to study the ruminal fermentative development in pre-and postweaning periods. Defaunation was achieved by rearing calves in isolation and its effect was studied after first appearance of ciliate protozoa (observed after 8 wk of age) in the faunated animals. Calves were fed colostrum for 24 h and whole milk until weaning at 8 wk of age. Ruminal content samples were collected on d 4, 1 wk, weekly to 8 wk, and then biweekly at 9, 11, and 13 wk of age. The samples were analyzed for fermentation products [pH, total volatile fatty acids (VFA) and ammonia N] and enzyme [carboxymethyl (CM) cellulase, xylanase, beta-glucosidase, alpha-amylase, beta-galactosidase, proteases, and urease] activities. Weekly feed intake increased with age, but was similar in both groups. Ruminal pH declined steadily during 0 to 4 wk of age and then stabilized. The total VFA concentration increased with the age. The ammonia N (mg/dL) concentration increased from 14.9 on d 4 to 32.4 at 4 wk, decreased to 17.6 at 8 wk, and then steadied during the postweaning period. Samples collected on d 4 had no fibrolytic activity. Xylanase (U/dL) appeared first (1 wk) followed by beta-glucosidase (U/dL) and CM cellulase (U/dL), which increased steadily from a low of 4.69, 0.08, and 2.95 to 31.8 (6 wk), 5.92 (7 wk), and 19.8 (8 wk), respectively, and the concentrations showed nonsignificant alterations during postweaning periods. The concentration of alpha-amylase (U/dL) increased from 34.3 on d 4 to 87.2 at 8 wk, and then decreased to 56.6 (13 wk). beta-Galactosidase increased up to 6 wk then decreased to trace level (0.20 U/dL) at 13 wk of age. The concentrations of proteases and urease reached a steady state after 1 wk of age. The effect of diet type on ruminal fermentation products and enzyme parameters was nonsignificant. However, a steady and proportional alteration in both parameters in response to dry feed intake with the advancement of age was seen in all calves. Defaunation increased total VFA (97.3 vs. 75.8 mM/L) and alpha-amylase activity (80.3 vs. 61.4 U/dL) and decreased ammonia N (16.4 vs. 21.1 mg/dL), whereas the effect on other parameters was nonsignificant. Ruminal fermentative changes responded to dry feed intake, but did not differ in response to animal protein in prestarter diet.

Synthesis of hydroxytyrosol, 2-hydroxyphenylacetic acid, and 3-hydroxyphenylacetic acid by differential conversion of tyrosol isomers using Serratia marcescens strain

We investigated to develop an effective procedure to produce the potentially high-added-value phenolic compounds through bioconversion of tyrosol isomers. A soil bacterium, designated Serratia marcescens strain, was isolated on the basis of its ability to grow on p-tyrosol (4-hydroxyphenylethanol) as a sole source of carbon and energy. During growth on p-tyrosol, Ser. marcescens strain was capable of promoting the formation of hydroxytyrosol. To achieve maximal hydroxytyrosol yield, the growth state of the culture utilized for p-tyrosol conversion as well as the amount of p-tyrosol that was treated were optimized. The optimal yield of hydroxytyrosol (80%) was obtained by Ser. marcescens growing cells after a 7-h incubation using 2 g/L of p-tyrosol added at the end of the exponential phase to a culture pregrown on 1 g/L of p-tyrosol. Furthermore, the substrate specificity of the developed biosynthesis was investigated using m-tyrosol (3-hydroxyphenylethanol) and o-tyrosol (2-hydroxyphenylethanol) as substrates. Ser. marcescens strain transformed completely m-tyrosol and o-tyrosol into 3-hydroxyphenylacetic acid and 2-hydroxyphenylacetic acid, respectively, via the oxidation of the side chain carbon of the treated substrates. This proposed procedure is an alternative approach to obtain hydroxytyrosol, 2-hydroxyphenylacetic acid, and 3-hydroxyphenylacetic acid in an environmentally friendly way which could encourage their use as alternatives in the search for replacement of synthetic food additives.

Ruminal fermentation and degradation patterns, protozoa population, and urinary purine derivatives excretion in goats and wethers fed diets based on two-stage olive cake: effect of PEG supply

Three experiments were conducted in Granadina goats and Segureña wethers fed at maintenance level to evaluate the effect of including a mixture of barley and a new by-product derived from olive oil extraction (two-stage dried olive cake) on ruminal degradation and passage kinetics (Exp. 1), fermentation pattern and protozoa population (Exp. 2), and urinary purine derivatives excretion (Exp. 3). Polyethylene glycol was supplied to the animals to evaluate the effects of tannins contained in the by-product. The experimental diets were as follows: alfalfa hay and alfalfa hay plus a concentrate, formulated with two-stage dried olive cake, barley, and a mineral-vitamin mixture either with or without the addition of polyethylene glycol to the drinking water. The inclusion of two-stage dried olive cake in the diet resulted in an increase of condensed tannins. Ruminal VFA concentration in goats and wethers increased (P < 0.05) and ammonia N (NH3-N) concentration decreased (P < 0.05). The inclusion of two-stage dried olive cake decreased (P < 0.001) urinary allantoin excretion only in wethers. Ruminal degradation profiles and fractional passage rates were similar in goats and wethers. The polyethylene glycol supply increased (P < 0.001) DM and N degradation rates in both animal species but did not modify the fractional passage rate. Ruminal fermentation patterns were also similar in goats and wethers and were affected by polyethylene glycol supply. In general, Entodiniomorphida and Holotricha protozoa counts were higher (P < 0.05) in the rumen of goats than of wethers. Protozoa count in wethers responded more to polyethylene glycol supply than in goats. The present work presents the first data obtained from a comparative study with sheep and goats concerning urinary excretion of purine derivatives. The excretion was similar in both animal species when fed alfalfa hay; however, polyethylene glycol affected only urinary allantoin excretion in wethers. Results suggest a greater sensitivity of wethers than of goats to two-stage olive cake condensed tannins.