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To counteract the negative effects of phytotannins, ruminants host a diverse community of bacteria that break down tannins. These bacteria not only possess tanninolytic activity but also have other functional relevance which has not been properly examined. Therefore, the present study was conducted to isolate and characterize tannin degrading bacteria (TDB) with possible fibrolytic activity from rumen of sheep fed tannin-rich diet. Based on the development of a clear zone on tannin-enriched agar plates, a total of 24 isolates were screened as tannin hydrolyzing bacteria. Majority of the isolates were gram positive cocci. The isolates could tolerate phenolic monomers such as ferulic acid, gallic acid, vanillic acid up to 30 mM and pyrogallol up to 10 mM however, the isolates failed to grow in presence of syringic acid, p-coumaric acid and p-hydroxybenzoic acid. Highest tannase activity was observed in isolate TDB23 while, lowest in isolates TDB2 and TDB5. In terms of fibrolytic activity, maximum endoglucanase, exoglucanase, and FPase activity was observed in isolate TDB9. In vitro digestibility of Prosopis cineraria leaves was considerably enhanced by inoculation of isolate TDB23 followed by TDB9. Therefore, the screened isolates demonstrated promising tannin and fibre degrading potential which can be further explored as direct-fed microbial in ruminants for effective utilization of tannin-rich fibrous feeds. • Tanninolytic bacteria were isolated from rumen contents of Malpura sheep. • 16 belonged to order Lactobacillales with tannase activity ranging from 1.2 to 12.5 mol gallic acid/min. • Total cellulolytic enzyme activity (FPase) of the isolates ranged from 0.14 to 9.80 U/ml. • Innoculation of the tanninolytic isolates effectively degraded Prosopsis cineraria leaves. [ABSTRACT FROM AUTHOR]

The aim of this study was to use meta-analytical methods to estimate effects of adding exogenous fibrolytic enzymes (EFE) to dairy cow diets on their performance and to determine which factors affect the response. Fifteen studies with 17 experiments and 36 observations met the study selection criteria for inclusion in the meta-analysis. The effects were compared by using random-effect models to examine the raw mean difference (RMD) and standardized mean difference between EFE and control treatments after both were weighted with the inverse of the study variances. Heterogeneity sources evaluated by meta-regression included experimental duration, EFE type and application rate, form (liquid or solid), and method (application to the forage, concentrate, or total mixed ration). Only the cellulase-xylanase (C-X) enzymes had a substantial number of observations (n = 13 studies). Application of EFE, overall, did not affect dry matter intake, feed efficiency but tended to increase total-tract dry matter digestibility and neutral detergent fiber digestibility (NDFD) by relatively small amounts (1.36 and 2.30%, respectively, or <0.31 standard deviation units). Application of EFE increased yields of milk (0.83 kg/d), 3.5% fat-corrected milk (0.55 kg/d), milk protein (0.03 kg/d), and milk lactose (0.05 kg/d) by moderate to small amounts (<0.30 standard deviation units). Low heterogeneity (I² statistic <25%) was present for yields and concentrations of milk fat and protein and lactose yield. Moderate heterogeneity (I² = 25 to 50%) was detected for dry matter intake, milk yield, 3.5% fat-corrected milk, and feed efficiency (kg of milk/kg of dry matter intake), whereas high heterogeneity (I² > 50%) was detected for total-tract dry matter digestibility and NDFD. Milk production responses were higher for the C-X enzymes (RMD = 1.04 kg/d; 95% confidence interval: 0.33 to 1.74), but were still only moderate, about 0.35 standardized mean difference. A 24% numerical increase in the RMD resulting from examining only C-X enzymes instead of all enzymes (RMD = 1.04 vs. 0.83 kg/d) suggests that had more studies met the inclusion criteria, the C-X enzymes would have statistically increased the milk response relative to that for all enzymes. Increasing the EFE application rate had no effect on performance measures. Application of EFE to the total mixed ration improved only milk protein concentration, and application to the forage or concentrate had no effect. Applying EFE tended to increase dry matter digestibility and NDFD and increased milk yield by relatively small amounts, reflecting the variable response among EFE types. [ABSTRACT FROM AUTHOR]

This research aimed to evaluate the effects of the supplementation of an exogenous fibrolytic enzyme (EFE; 1:1 v/v mixture of cellulase PLUS and xylanase PLUS, Dyadic International Inc, USA) to untreated (Control(WS)) and urea pretreated wheat straw (UWS) on feed intake, digestibility, nitrogen balance, ruminal fermentation, growth performance and blood metabolites of meat lambs. The diet contained 50 % wheat straw and 50 % concentrate (DM basis), and the EFE was applied at 1 mL/ kg DM to the straw. Lambs were arranged in a completely randomized design with four treatments (n = 5 lambs per treatment): Control(WS), WS+EFE, UWS, UWS+EFE. The lambs were housed individually in metabolic crates for 56 d divided into three experimental periods: d 0–21 adaptation period, d 21–28 digestibility trial and average daily gain (ADG) measurements and d 28–56 for only ADG measurements. All studied treatments have no effect on nutrients intake. As compared to the control WS, only the EFE supplementation affected the nutrients digestibility. The EFE addition improved the digestibility of dry matter by 9 % and 14 %, organic matter by 8 % and 13 %, crude protein by 7 % and 6 %, neutral detergent fiber by 24 % and 47 %, and acid detergent fiber by 30 % and 48 % for WS+EFE and UWS+EFE as compared to Control(WS) and UWS, respectively. The ruminal NH 3 -N concentrations measured during d 21 , d 24 and d 28 were lower for animals fed WS+EFE and UWS+EFE than those fed on Control(WS) and UWS. The nitrogen retention improved only for UWS+EFE. The EFE supplementation to straw had no effect on ruminal pH and blood metabolites. For the ADG, the highest total ADG improvement (22 %) was recorded for UWS+EFE. These results indicate that urea treatment alone was inefficient in improving straw digestibility and lamb growth performance. However, the EFE supplementation was efficient on lamb growth, especially when combined with urea treatment due to increased ruminal digestibility and nitrogen retention. • EFE upgrade the nutritional value of wheat straw as an ingredient in lamb diets. • Exogenous enzyme supplementation (EFE) improves digestibility and daily weight gain in fattening lambs. • The urea treatment and EFE association were efficient on lamb growth performance. [ABSTRACT FROM AUTHOR]

The aim of this study was to assess the effect of fecal inocula from horses fed on concentrate (restricted amount daily) and oat straw ( ad libitum ) supplemented with fibrolytic enzymes on in vitro hindgut activity. Cellulase (CE), xylanase (XY), and CE + XY (1:1 vol/vol; CX) were tested at three levels (μL/g dry matter [DM]): 0, 1, and 3, in addition to control without enzyme addition. Fecal inocula were collected from 16 Quarter Horse mares supplemented with enzyme at 0 (without enzyme), or fed 5-mL enzyme/mare/d of CE (FCE), XY (FXY), or CE + XY (1:1 vol/vol; FCX) for 15 days. The fecal content mixed with the culture media were used for incubation in bottles containing 1-g DM of substrate (a mixture of concentrate and oat straw [1:1 DM]). Gas (GP), methane (CH 4 ), and carbon dioxide productions were measured at 2, 4, 6, 8, 10, 12, 24, and 48 hours after incubation. Interactions occurred ( P < .05) between fecal source × enzyme product for the asymptotic GP, the rate of GP, CH 4 production, and fermentation kinetic parameters. Moreover, interactions were observed ( P < .05) between fecal source × enzyme product × enzyme dose for the rate of GP, CH 4 production, and DM digestibility. Xylanase at 3-μL/g DM with FXY fecal increased ( P < .05) the asymptotic GP, short-chain fatty acids, and microbial protein productions with lowering ( P < .05) partitioning factor. At 24 and 48 hours and without enzyme, FCX and FXY, had the highest ( P < .05) CH 4 production. It can be concluded that XY enzyme at 3-μL/g DM was the most effective compared with other treatments. [ABSTRACT FROM AUTHOR]

This study aimed to carry out a systematic review and meta-analysis to evaluate the efficacy of chemical, enzymatic, and microbial additives on the silage quality and performance of sheep. After article selection using the Cochrane Library, Embase, Web of Science, LILACS and MEDLINE-PubMed databases and a manual search of scientific journals and the references of articles selected in the systematic review, 4257 articles published through May 2021 were identified. Fifty-four randomized control trials eligible for review were selected. Data were grouped into subgroups by the additive type (Mho = homofermentative microbial inoculant; Mhe = heterofermentative microbial inoculant; MMi = microbial inoculant mixture; Fa = formic acid; En = enzymes). The meta-analysis was performed using the "meta" package of R software. The data were analyzed using the random effects model and the raw mean difference with a 95% confidence interval (p < 0.05). Fa use reduced (p < 0.05) the silage crude protein digestibility (CPD) (−20.7 g/kg DM), and the ammonia nitrogen (NH 3 –N) (−53.6 g/kg total N), and acetic acid (−5.06 g/kg DM) content and pH (−0.325) and increased the animal nitrogen retention (1.30 g/day), and the dry matter (DM) (14.1 g/kg NM), crude protein (CP) (20.4 g/kg DM) and water-soluble carbohydrate (WSC) (11.5 g/kg DM) content. En use reduced (p < 0.05) the silage neutral detergent fiber digestibility (NDFD) (−33.1 g/kg DM), CP (−10.8 g/kg DM), neutral detergent fiber (NDF) (−49.1 g/kg DM), NH 3 –N (−25.5 g/kg total N) and acetic acid (−4.43 g/kg DM) content. Mho use increased (p < 0.05) the dry matter intake (DMI) (95 g/day), dry matter digestibility (DMD) (28.8 g/kg DM), CPD (26.6 g/kg DM), WSC (2.55 g/kg DM), nitrogen intake (2.23 g/day), retained nitrogen (2.19 g/day) and lactic acid (10.4 g/kg DM) content and reduced the mold count (−1.01 log 10 CFU/g), NH 3 –N (−13.4 g/kg total N), acetic acid (−3.31 g/kg DM) content and aerobic stability (−33.8 h) of the silage. Mhe use increased (p < 0.05) the DMI (78.6 g/day), carcass yield (0.906%), DM (9.96 g/kg NM), aerobic stability (23 h) and acetic acid (19.9 g/kg DM) content and reduced the NDF (−20 g/kg DM) and ADF (−16.2 g/kg DM), yeast (−0.852 log 10 CFU/g) and mold (−0.469 log 10 CFU/g) counts. MMi use increased (p < 0.05) the average daily gain (17 g/day), DM (13.4 g/kg NM) and yeast (0.930 log 10 CFU/g) count and reduced the silage pH (−0.037). All additive types improved the silage quality, but only MMi improved weight gain in sheep. Mhe increased silage aerobic stability and can be used for this purpose on commercial farms. • Formic acid reduced protein digestibility and increased nitrogen retention. • Enzymes reduced neutral detergent fiber digestibility and content and NH 3 –N. • Homofermentative microbial inoculant increased dry matter intake and digestibility. • Heterofermentative microbial inoculant increased intake and aerobic stability. • Inoculant mix increased average daily gain and reduced silage pH. [ABSTRACT FROM AUTHOR]

Supplementation of rice straw based rations (30% rice straw, dry matter basis) with fibrolytic enzymes is of potential interest to improve nutrient utilization and hence animal performance, but its efficacy is not yet demonstrated in growing goats. In a parallel design, eighteen young goats were fed a total mixed ration (TMR) based on rice straw either with or without supplemental fibrolytic enzymes. Addition of fibrolytic enzymes to the TMR increased the apparent digestibility of neutral and acid detergent fiber by 10.0 and 9.1%, respectively. Enzyme supplementation raised concentrations of total volatile fatty acids in rumen fluid with an associated increase in the proportion of acetate and total bacteria counts. Fortification of TMR with fibrolytic enymes increased average daily weight gain by 34.7% and the efficiency of feed utilization by 28%. It is concluded that the nutritive value of rice straw based rations can be upgraded by supplementation with fibrolytic enzymes, leading to enhanced ruminant production. [ABSTRACT FROM AUTHOR]

This study investigated the effects of palm oil and fibrolytic enzyme supplementation in high forage diets on growth, carcass characteristics and fatty acid composition of lambs. Forty South African Mutton Merino ram lambs were randomly assigned to four treatment groups (n = 10 lambs/ treatment) and fed a basal total mixed ration (TMR). The treatments were: TMR diet with Megalac as bypass oil (control); TMR diet supplemented with 3% palm oil; TMR diet with cellulase and xylanase enzymes and TMR diet supplemented with 3% palm oil and cellulase and xylanase enzymes. The lambs were slaughtered at a target weight of about 42 kg. Palm oil supplementation resulted in a longer feeding period (P < 0.05) and lower dressing percentage (P < 0.01), but the carcasses had higher meat yield (P < 0.01) and lower fat content (P < 0.05) compared to the other treatment groups. Additionally, palm oil supplementation increased the proportion of C18:0 (P < 0.05) while decreasing (P < 0.05) the proportion of C14:0 (P < 0.05) and C16:0 (P < 0.05) in fat depots, which may be beneficial for human health. The fibrolytic enzyme treatment had minimal effects on growth, carcass characteristics, meat quality and fatty acid composition of lambs. The interaction effect of palm oil and fibrolytic enzymes had positive effects on the UFA: SFA ratio due to an increase (P < 0.05) in C20:3n6 and C20:4n6 and a reduction (P < 0.05) in saturated fatty acids. The results suggest that methane mitigation strategies through palm oil and enzyme supplementation can be used in lamb diets without adverse effects on product quality. • Dietary supplementation of palm oil improved carcass and meat quality of lambs. • Enzyme treatment of forage diets had minimal effects on meat quality traits. • Palm oil and enzymes can be used in lamb's diets without compromising meat quality. [ABSTRACT FROM AUTHOR]

Abstract: A series of in vitro experiments were conducted to assess three fibrolytic enzyme preparations as potential feed additives in equine diets. The three fibrolytic enzyme preparations were a concentrated cellulase (E1), an acid cellulase (E2) and a concentrated xylanase (E3). The enzymes were evaluated on their ability to modify the cell wall fraction of high-temperature dried lucerne (HTL) under various experimental conditions including differences in temperature, pH, incubation period, substrate levels and particle size to enable selection of the enzyme preparation most effective in the hydrolysis of lucerne. Results showed enzyme activities (as measured by reducing sugar assays) to be greatest at 50°C, pH 5 and over an incubation period of greater than 20h. E1 exhibited the greatest effect on total monosaccharide release from the HTL compared to E2 and E3. Moreover, dry matter (DM) and total non-starch polysaccharide (TNSP) losses were also greater in HTL treated with E1 compared to E2 and E3. Therefore, since the cell wall fraction of HTL contained substantial amounts of cellulose, the enzyme with the highest cellulase activity (Enzyme 1) was most effective in hydrolysing the cell walls of HTL. Consequently, it would appear that the application of exogenous fibrolytic enzyme preparations to forages requires the chemical characterisation of the target forage to enable selection of enzymes that are (a) most suitable to degrade the cell wall components of the candidate forage and (b) effective under field conditions. [Copyright &y& Elsevier]

Abstract: An experiment was conducted to evaluate effects of an enzyme filtrate or a crude enzyme preparation on in vitro disappearance of six common fibrous feeds being: alfalfa hay, brome grass hay, cottonseed hulls, soybean hulls, wheat bran and wheat straw. A commercial liquid feed grade enzyme product originating from a strain of Trichoderma reesei was used. To obtain filtrates, the crude enzyme preparation was filtered through membranes with molecular weight cutoffs of 5 and 10kDa. Feeds were exposed to enzymes, filtrates, or a buffer, for 20h. Filtrates and crude enzyme preparation were diluted in 12.5mM sodium citrate buffer. In vitro fermentation followed treatment of the feeds for 24 and 48h. Release of glucose and total monosaccharides was quantified following treatment of alfalfa hay and soybean hulls at 2 and 24h, and release of phenolic monomers was measured at 24h of incubation. For in vitro dry matter disappearance (IVDMD), treatment x time interactions occurred for alfalfa hay (P=0.01) and cottonseed hulls (P=0.04). Higher (P<0.01) IVDMD occurred at 48h of incubation vs 24h. The IVDMD of alfalfa hay and wheat bran was not affected by treatments. The crude enzyme preparation (CE) increased IVDMD compared to Ctrl for brome grass hay, cottonseed hulls, soybean hulls and wheat straw. Likewise, CE resulted in higher IVDMD than the 5 and 10kDa treatments for the same feeds. Release of total monosaccharides from soybean hulls and alfalfa hay was higher (P<0.001) after 24h than after 2h of treatment. Although the 10kDa treatment resulted in release of monosaccharides from soybean hulls, the greatest response was from CE after the 24h treatment. Phenolics were released from alfalfa hay and wheat straw as a result of the treatments during a single 24h incubation, with the biggest response from the 10kDa and CE. When the enzyme complex from a commercial T. reesei enzyme product was partitioned by molecular weight and used as a treatment for brome grass hay, cottonseed hulls, soybean hulls and wheat straw, both the filtrates and the crude enzyme preparation increased IVDMD, with the crude enzyme preparation treatment causing the biggest IVDMD response. Release of monosaccharides and phenolics from the substrates also occurred as a result of the treatments. The addition of fungal enzymes or their subunits may prove a viable management opportunity to increase rumen digestibility of forages to enhance animal performance. [Copyright &y& Elsevier]

Abstract: To obtain an optimal feruloyl and acetyl esterase production of an anaerobic Neocallimastix sp. YQ2 grown on either Chinese wildrye grass hay (CW) or alfalfa hay (AH) or corn stalk (CS), three simultaneous 2×4 factorial experiments of 10-day pure cultures were applied with two levels of glucose (G+: glucose added at a level of 1.0g/L and G−: without glucose) and four levels of N source (N1: 1.0g/L yeast extract, 1.0g/L tryptone and 0.5g/L (NH4)2SO4; N2: 2.8g/L yeast extract and 0.5g/L (NH4)2SO4; N3: 1.6g/L tryptone and 0.5g/L (NH4)2SO4; N4: 1.4g/L yeast extract, 1.7g/L tryptone). Optimal combinations of glucose and N supplements for YQ2 to produce ferulic acid esterase, acetyl esterase, xylanase, carboxymethyl cellulase and avicelase were G+N2 for CS, G−N3 for CW, G−N3 for CW, G+N2 for CS, and G+N2 for CW, respectively. These five kinds of fibrolytic enzyme had different variation tendencies and maximum activity at different times of incubation. The fungus produced more total volatile fatty acids, and less propionic acids and iso-valeric acids, when CS was used as growth substrate, as well as more acetic acids when CW was used than when AH was used (P<0.05). As for the enzymological characteristics of feruloyl and acetyl esterase, Michaelis constants (K m) and maximum velocities (V max) of ferulic acid esterase against methyl ferulate at pH 6.0 and 39°C were 90μM and 1.15mU, and the Michaelis constants and maximum velocities of acetyl esterase at pH 7.0 and 39°C were 2.97mM and 294mU with specific substrate of p-nitrophenyl acetate. The crude enzyme preparation of the fungi grown on CS with the G+N1 combination had higher potential to release ferulic acid, and p-coumaric acid in CS up to 129.8g/kg the alkali-extractable ferulic acid and 88.1g/kg the alkali-extractable p-coumaric acid, respectively (P<0.05). The strong capability to hydrolyse plant materials by the fungus can be used to understand the degradation of fibre-rich feedstuffs in the rumen and also open prospects for development of direct fed feed enzyme products for ruminants. [Copyright &y& Elsevier]

Abstract: The effects of two exogenous fibrolytic enzyme products on ruminal disappearance and fermentation of oat straw-wheat middlings based diets were evaluated. Six steers (322±34.4 kg body weight) fitted with ruminal cannulas were used in a 3×3 Latin square replicated. The treatments consisted of: 1) control, 2) Fibrozyme (2 g/kg dry matter), and 3) Promote (3 ml/kg dry matter). Both, Fibrozyme (Alltech Inc.) and Promote NET (Cargill Corp.) were sprayed as liquid onto diets and feeds 24 h before feeding. Samples of diets were ruminally incubated from 0 to 72 h. Enzymes did not change dry matter intake, average daily gain and feed conversion. Fibrozyme increased crude protein (CP) disappearance rate of diet, while Promote increased CP total disappearance. In diets, enzymes did not affect ruminal neutral detergent fiber (NDF) and acid detergent fiber (ADF) fractions. Fibrozyme and Promote did increase CP total disappearance, ADF potential disappearance and ADF disappearance rate of wheat middlings, as well as dry matter (DM) and CP total disappearance, NDF disappearance rate, ADF potential disappearance and ADF disappearance rate of oat straw. Ruminal pH values were higher with enzymes, as compared to control. Total volatile fatty acids concentration and molar proportion of acetate and butyrate were not affected by both enzymes, but molar proportion of propionate was lower and acetate:propionate ratio higher with Promote than control. Fibrozyme and Promote did increase DM and CP soluble fractions of diets, as well as, ADF potential disappearance of wheat middling and oat straw. [Copyright &y& Elsevier]

Abstract: The objective was to determine the effects of an exogenous fibrolytic enzyme mixture (enzyme) on intake, digestion and ruminal fermentation of Guinea grass (Panicum maximum var. Mombasa) hay cut at 35 and 90d of growth using four Suffolk lambs (74.0±2.01kgbodyweight) fitted with ruminal and duodenal cannulae. The experimental design was a repeated Latin Square within a 2×2 factorial arrangement (i.e., enzyme, 0 and 3g/d/lamb; Guinea grass, 35 and 90d). Crude protein (CP) intake was higher, but acid detergent fibre (ADF) intake was lower, with Guinea grass 35d versus 90d. Except for CP, daily duodenal and fecal flow of dry matter (DM), CP, neutral detergent fibre (NDF) and ADF were higher with Guinea grass 90d versus 35d. Ruminal, duodenal and total tract digestion, and ruminal ammonia and acetate were higher, but ruminal pH, propionate and butyrate were lower, with Guinea grass 35d versus 90d. Fibrolytic enzymes reduced duodenal ADF flow and forestomach digestion. There were no enzyme effects on DM intake, N balance, ruminal degradation, total tract digestion, ruminal fermentation, as well as ruminal protozoal counts. These exogenous fibrolytic enzymatic did not increase ruminal digestion of Guinea grass. [Copyright &y& Elsevier]

Abstract: This experiment was designed to study effects of exogenous fibrolytic enzymes on digestibility and ruminal fermentation of total mixed rations (TMR) with different forage:concentrate (F:C) ratios. The experimental design was a 6×6 Latin square with six ruminally cannulated Ramboulliet lambs (58±7.4kg body weight) used in a 3×2 factorial arrangement of treatments using three forage:concentrate (F:C) ratios (400:600, 500:500, 600:400kg/kg) and two (0 or 2g) levels of fibrolytic enzymes/kg TMR dry matter (DM). Exogenous fibrolytic enzymes increased the soluble fraction of DM (P<0.01) and ruminal in situ disappearance rate of DM and neutral detergent fibre (aNDF; P<0.001). However, there were no differences among treatments in DM and aNDF in vivo digestibility due to enzyme addition to the diet. Feed intake and N balance were also not affected by enzymes, and ruminal fermentation patterns were unchanged. Exogenous fibrolytic enzymes improved ruminal disappearance rates of DM and aNDF, but had no impact on lamb performance or ruminal fermentation. [Copyright &y& Elsevier]

Abstract: The extracts of pods of Acacia concinna (Shikakai), seed pulp of Terminalia chebula (harad), Terminalia belerica (bahera), Emblica officinalis (amla) and seed kernel of Azadirachta indica (neem seed) in different solvents (ethanol, methanol and water) were evaluated for their effect on methane production, enzymes activities and rumen fermentation in in vitro gas production test. Gas production per gram dry matter (DM) of substrate (wheat straw and concentrate mixture in 1:1 ratio) was significantly (P<0.05) higher with extracts of A. concinna, E. officinalis and T. belerica as compared to control. Among the extracts tested only methanol extract of T. chebula suppressed in vitro methane production significantly (P<0.05). Specific activities of carboxymethylcellulase (CMCase) and xylanase were similar (P>0.05) among the extracts at both the levels tested, whereas, the activity of acetylesterase was reduced significantly (P<0.05). Total volatile fatty acids (TVFA) were significantly (P<0.05) decreased with extracts of T. chebula and A. indica. There was a decrease (P<0.05) in acetate to propionate ratio due to addition of the extracts of A. concinna and A. indica in incubation medium as compared to control. In vitro dry matter and organic matter degradabilities of feed (g/g) were decreased significantly (P<0.05) with all the extracts compared to that of control. The extracts of A. concinna and A. indica at 0.25 and 0.50ml levels and extracts of T. chebula at 0.50ml level reduced total protozoa counts significantly. Similar trends were observed for small and large entodiniomorphid protozoa counts. However, no effect (P>0.05) was found on holotrich protozoa numbers. The results indicated that methane emission is not essentially associated with protozoa activity since among three seed pulps with high antiprotozoal activity, only T. chebula (methanol extract) had antimethanogenic activity. The methanol extract of seed pulp of T. chebula appears to have a potential to be used for mitigation of enteric methane production, but the level of feeding will have to be evaluated so that there is minimum adverse effect on the degradability of feed in the rumen. [Copyright &y& Elsevier]

Abstract: A study was conducted to assess the effect of condensed tannins on the activity of fibrolytic enzymes from the anaerobic rumen fungus, Neocallimastix hurleyensis and a recombinant ferulic acid esterase (FAE) from the aerobic fungus Aspergillus niger. Condensed tannins were extracted from the tropical legumes Desmodium ovalifolium, Flemingia macrophylla, Leucaena leucocephala, Leucaena pallida, Calliandra calothyrsus and Clitoria fairchildiana and incubated in fungal enzyme mixtures or with the recombinant FAE. In most cases, the greatest reductions in enzyme activities were observed with tannins purified from D. ovalifolium and F. macrophylla and the least with tannins from L. leucocephala. Thus, whereas 40μgml−1 of condensed tannins from C. calothyrsus and L. leucocephala were needed to halve the activity of N. hurleyensis carboxymethylcellulase (CMCase), just 5.5μgml−1 of the same tannins were required to inhibit 50% of xylanase activity. The β-d-glucosidase and β-d-xylosidase enzymes were less sensitive to tannin inhibition and concentrations greater than 100μgml−1 were required to reduce their activity by 50%. In other assays, the inhibitory effect of condensed tannins when added to incubation mixtures containing particulate substrates (the primary cell walls of F. arundinacea) or when bound to these substrate was compared. Substrate-associated tannins were more effective in preventing fibrolytic activities than tannins added directly to incubations solutions. It was concluded that condensed tannins from tropical legumes can inhibit fibrolytic enzyme activities, although the extent of the effect was dependent on the tannin, the nature of its association with the substrate and the enzyme involved. [Copyright &y& Elsevier]

Presents abstracts of several articles on ruminant nutrition for animals. "Monensin or Decoquinate in High Concentrate Diets Fed to Santa Ines Lambs," by I. Susin, C. Q. Mendes, A. V. Pires and I. U. Packer; "Rate and Extent of In Situ DM Disappearance of Feedstuffs in Cows Fed Different Strains of Yeast," by J. C, Silva and L. W. Greene; "Fermentable and Nutritional Characteristics of Fermented Feedstuffs Added Aspergillus Oryzae and Saccharomyces Cerevisiae," by P. Byung Ki, R. Chang Six and S. Jong Suh; "Effect of Supplemental Chromium on Tissue Chromium Concentrations in Cattle," by J. W. Spears, K. E. Lloyd, M. E. Tiffany and M. T. Socha.

Presents abstracts of several articles on ruminant nutrition for animals. "Monensin or Decoquinate in High Concentrate Diets Fed to Santa Ines Lambs," by I. Susin, C. Q. Mendes, A. V. Pires and I. U. Packer; "Rate and Extent of In Situ DM Disappearance of Feedstuffs in Cows Fed Different Strains of Yeast," by J. C, Silva and L. W. Greene; "Fermentable and Nutritional Characteristics of Fermented Feedstuffs Added Aspergillus Oryzae and Saccharomyces Cerevisiae," by P. Byung Ki, R. Chang Six and S. Jong Suh; "Effect of Supplemental Chromium on Tissue Chromium Concentrations in Cattle," by J. W. Spears, K. E. Lloyd, M. E. Tiffany and M. T. Socha.

This experiment was conducted to study the effects of fibrolytic enzymes (Fibrozyme) on gain and digestibility of steers grazing stargrass and sugar cane plus urea as a complementary forage in tropical conditions. Twenty crossed (Bos taurus×Bos indicus) steers (270±30 kg BW) were used in a grazing trial (80 days), feeding individually concentrate (1 kg/d, 14% CP) and urea treated sugar cane (USC), in a completely randomized design according to the following treatments: (1) Grazing control (GC); (2) USC-0; (3) USC+15 g d−1 Fibrozyme (USC-15); (4) USC+30 g d−1 Fibrozyme (USC-30). The stocking density was 6 steers ha−1. Forage intake was estimated with makers (chromic oxide and acid insoluble ash). Gain was improved with fibrozyme showing a positive (P<0.01) response to fibrozyme level (g d−1: C 484; USC-0 548; USC-15 634; USC-30 776) associated to a positive (P<0.05) increment of sugar cane intake (kg d−1: C 0.0; USC-0 3.04; USC-15 3.15; USC-30 3.24) and a higher DM digestibility (P<0.05) than control group (%: C 65.0; USC-0 73.4; USC-15 71.4; USC-30 72). No effect was detected in stargrass or total DM intake. Results indicated that fibrozyme increased nutrient intake from sugar cane improving daily gain. [Copyright &y& Elsevier]

A dual effluent continuous culture system (CC) was used to investigate effects of pH and addition of fibrolytic enzymes to a dairy cow diet on fermentation, digestibility and bacterial protein synthesis. The experiment was a completely randomized design with two factorial treatments and four replications. Factors were fermenter pH level (5.5, 6.0 and 6.5) and fibrolytic enzyme supplementation (control and enzyme). Fermenters were fed twice daily an early lactation diet that consisted of about 50% forage and 50% barley-based concentrate (dry matter [DM] basis). The enzyme product used was a commercial blend which contained relatively high xylanase and cellulase activities (Promote®, Agribrands Inc., St. Louis, MO). The enzyme (0.2 ml) was diluted into 20 ml of water and then sprayed onto 1 kg of total mixed ration (dried in an oven at 55 °C and ground through a 4.5-mm screen) prior to feeding. Total volatile fatty acids (VFA) concentration and its molar proportions increased linearly (P<0.04) with increasing fermenter pH. Degradabilities of DM, organic matter (OM) and fibre, except crude protein (CP), were affected (P<0.05) by fermenter pH. Considerable increase in digestion was observed when fermenter pH increased from low (5.6) to medium (6.0), but effect of a further increase from medium (6.0) to high (6.0) were negligible. Enzyme supplementation did not affect total VFA concentrations, but increased molar proportions of acetate (P<0.01) and reduced that of propionate (P<0.01), as a result of increased digestion of NDF (P<0.01) and ADF (P<0.04). However, degradation of CP and bacterial protein synthesis were not affected by adding fibrolytic enzymes into the diet. There was a numerical (P>0.13) interaction between pH and enzymes for fibre digestion; the increase in digestibility of NDF due to enzyme supplementation was lower (8%) when mean fermenter pH was 5.6 compared to when pH was over 6.0 (18%), indicating that the effectiveness of enzymes can be reduced in low rumen pH conditions. The present results indicated that manipulation of fermenter pH in CC was highly effective in altering fermentation pattern and fibre degradation. Fibrolytic enzymes have the potential to improve in vitro fibre degradation, but are not expected to fully overcome the limits to fibre digestion caused by low pH. [Copyright &y& Elsevier]

• Ammonia Fibre Expansion (AFEX) pretreatment of straws and corn stover increased in situ effective ruminal degradability (by +28 to +126%). • Supplementing a beef cattle diet with recombinant xylanase increased rumen degradability of crop residues pretreated with AFEX (by +3%). • AFEX treatment has tremendous potential to improve the digestibility of crop residues. • Xylanase enzyme may be more effective for less lignified feeds with high concentrations of hemicellulose. Low digestibility of crop residues limits their use as animal feeds. The study examined the potential of Ammonia Fibre Expansion (AFEX) technology and dietary supplementation of a preselected recombinant xylanase to improve the in situ degradability of four crop residues for ruminants. AFEX pretreatment uses anhydrous ammonia, moisture, moderate temperature, and a short period of high pressure and results in partial lignin solubilization and hemicellulose hydrolysis, and increased surface area of substrate for microbial attachment. In situ neutral detergent fibre degradabilities of untreated (control) and AFEX pretreated crop residues (barley straw, corn stover, rice straw, and wheat straw) were determined in 8 heifers using a 2-period cross-over design with two dietary treatments (without and with XYL10C; 1,4-β-xylanase; recombinant enzyme from glycoside hydrolase family 10 produced by Aspergillus niger). The enzyme was diluted in water and applied to the barley straw (6.6 × 104 IU enzyme/kg straw dry matter) component of the basal diet (30 g/100 g diet dry matter) and to the control and AFEX crop residues incubated in situ. There were no interactions between enzyme and crop residues for A, B, or A + B fractions, indicating no enzyme × substrate specificity. Averaged across crop residues, enzyme slightly decreased the A fraction (P < 0.001) and slightly increased the B fraction (P = 0.02), such that there was no overall effect on A + B (P = 0.21). However, there were significant interactions between enzyme and AFEX for kd (P = 0.026); enzyme had no effect on control crop residues but it increased kd of AFEX residues by 12% (0.0323 vs. 0.0361 /h). As a result, xylanase supplementation increased the effective rumen degradability of crop residues by about 3%, but only when they were pretreated with AFEX (interaction, P ≤ 0.098). AFEX greatly increased effective ruminal degradability (+ 28 to + 126% depending upon the crop residue; P < 0.001), mainly by increasing the B fraction and decreasing the undigested fibre fraction, indicating increased accessibility of substrate to rumen microbial enzymes. The study demonstrates the tremendous potential of AFEX treatment to improve the feeding value of crop residues. Enzyme XYL10C was more effective for AFEX crop residues, possibly due to increased accessibility to substrate, suggesting that this enzyme may be more effective for less lignified and pretreated feeds. [ABSTRACT FROM AUTHOR]