Effects of peptidase inhibitors and other additives on fermentation and nitrogen distribution in perennial ryegrass silage

The effects of formic acid, three concentrations of formaldehyde in a formic acid/formaldehyde mixture and cysteine‐peptidase inhibitors, 1‐trans epoxysuccinyl‐leucylamido‐(4‐guanidino) butane (E‐64), N‐ethylmaleimide and cystamine on nitrogen (N) distribution during ensilage of perennial ryegrass (Lolium perenne) were investigated. A third cut or perennial ryegrass (163 g dry matter kg⁻¹ and 61 g water‐soluble carbohydrate kg⁻¹ dry matter) was ensiled in two silo sizes; formaldehyde‐treated herbage was ensiled only in larger silos (500–550 g herbage) and cysteine‐peptidase inhibitor‐treated herbage only in smaller silos (130–150 g herbage). Control silages were poorly fermented but contained low concentrations of butyric acid and ammonia N indicating little activity of spoilage bacteria. Formic acid increased peptide N concentrations (P<0.01) in silage from smaller silos but had little effect on other N constituents; in the larger silos, formic acid reduced soluble non protein nitrogen (NPN) and ammonia‐N concentrations and increased peptide N concentrations. Increments in formaldehyde reduced silage soluble and ammonia N concentrations (linear effect; P<0.001). N‐Ethylmaleimide and E‐64 reduced soluble NPN concentrations (P<0.05) but had little effect on other N constituents. Cystamine, however, increased silage peptide N concentrations. Gel filtration on Sephadex G‐25 of silage juice prepared from control and formic acid‐treated silages suggested that most silage peptides were small, with molecular weights of less than 520 Da. © 1999 Society of Chemical Industry     

The effect of the addition of cell-wall degrading enzymes at ensiling on the response to postruminal supplementation of protein in dairy cows receiving a silage-based diet

Two silages were prepared from the same sward of perennial ryegrass. One was ensiled without additive and the other was ensiled with the addition of a mixture of cellulase and hemicellulase enzymes. Silage intake and milk production responses to the infusion of 230 g day^?1 into the abomasum were examined in four dairy cows in a 4 × 4 latin square design experiment with 14-day periods. The four treatments were (i)no-additive silage without casein, (ii) no-additive silage with casein, (iii) enzyme-silage without casein, and (iv) enzymesilage with casein. Both silages were given ad libitum with 5 kg day^?1 of a barley-soya bean meal mixture. Casein infusion tended (0.10 < P > 0.05) to increase the intake of the no-additive silage but the intake of the enzyme silage was unaffected. When casein was not given, the yields of milk and milk constituents were greater (P <0.05) for the enzyme-silage than for the no-additive control. Casein infusion increased (at least P <0.05) the yields of milk and milk protein with both silages but the increases were substantially greater with the no-additive silage; values were for milk yield (kg day^?1) 14.4 and 16.6 (no-additive), 15.9 and 16.8 (enzyme); and for milk protein yield (g day^?1) 464 and 558 (no-additive), 499 and 566 (enzyme) for the unsupplemented and casein treatments, respectively. The amino acid profile suggested that the supply of amino acids from the small intestine was greater with the enzyme-silage.     

Effect of applying formic acid,heterolactic bacteria or homolactic and heterolactic bacteria on the fermentation of bi‐crops of peas and wheat

This work aimed to compare the effectiveness of bacterial inoculants or a chemical additive for preserving whole‐crop silages made from wheat, two pea varieties (cv Magnus or Setchey) or intercrops of wheat and both pea varieties. The forages were harvested when the wheat and peas were at the late milk and yellow wrinkled stages respectively, and conserved in five replicate mini silos without treatment (control) or after treatment with 2.5 g kg^?1 of formic acid (FA) or 1 × 10⁶ cfu g^?1 fresh forage of either of two bacterial inoculants (WholeCrop Gold (WCG) or WholeCrop Legume (WCL), Biotal Ltd, Cardiff, UK). WCG contained Lactobacillus buchneri, while WCL contained L buchneri, L plantarum and Pediococcus pentosaceus. Chemical composition, fermentation characteristics and in vitro digestibility were measured after 65 days of ensiling. Additive‐treated bi‐crops had lower (P < 0.05) concentrations of soluble N, ammonia N and lactic acid than the controls. Inoculant‐treated bi‐crops had higher (P < 0.001) acetic acid and lower (P < 0.001) residual water‐soluble carbohydrate (WSC) concentrations than FA‐treated bi‐crops. WCL‐treated bi‐crops had similar residual WSC concentrations to and higher (P < 0.05) starch concentrations than WCG‐treated bi‐crops. Unlike Magnus pea bi‐crops, Setchey pea bi‐crops treated with WCL had lower concentrations of ammonia N (P < 0.01) and acetic acid (P < 0.001) and higher concentrations of starch (P < 0.001) and lactic acid (P < 0.05) than those treated with WCG. For both bi‐crops, FA‐treated bi‐crops were more stable (P < 0.05) than inoculant‐treated or untreated silages, and the stability of inoculant‐treated and untreated silages was similar. Formic acid treatment was also the most effective at reducing WSC losses in the bi‐crop and pea silages. Inoculant treatment reduced proteolysis in these forages but did not prevent spoilage in the bi‐crops. Additive treatment reduced yeast counts but did not improve the fermentation in wheat silages. Copyright © 2004 Society of Chemical Industry     

Effects of extraction and reconstitution of ryegrass juice on fermentation,digestion and in situ degradation of pressed cake silage

Primary growth of Italian ryegrass was fractionated into green juice and pressed cake (PC). PC was ensiled either directly or after reconstitution with the juice which was spray dried and then added to water before ensiling (RPC). This process was aimed at distinguishing between chemical (removal of nutrients) and physical (mechanical disintegration) effects of fractionation. Two additional wilted silages were prepared from long cut or chopped Italian ryegrass (WL and WC, respectively). The fermentative quality, digestion and in situ degradation of dry matter for the four silages were compared. WC, RPC and PC silages indicated lactate-rich fermentation while WL silage had a comparatively low lactate content. PC silage had a lower (P<0·05) pH value with lower (P<0·05) amounts of organic acids compared with WC and RPC silage, suggesting that removal of buffering components with the juice had greater effects than shredding on fermentation of PC silage. The digestibility of protein was lower (P<0·05) in PC than WL silage but the reduction was compensated for in RPC silage. Ruminal concentrations of total volatile fatty acids were the highest (P<0·05) when goats fed WL silage while those on the other silages had similar concentrations. Ruminal pH was lower (P<0·05) in goats fed PC than WC silage and the difference was not fully reversed by reconstituting the juice to PC. Juice extraction decreased (P<0·05) the soluble fraction and the rate of disappearance of dry matter in the rumen but the potential degradability was not different among treatments. These results suggest that both chemical and physical changes due to the fractionation affect the characteristics of digestion of PC silage while the removal of nutrients has a major role in the modified silage fermentation. © 1997 SCI.     

Ensiling characteristics and ruminal degradation of Italian ryegrass and lucerne silages treated with cell wall-degrading enzymes

Two experiments were carried out to investigate the effect of added cell wall-degrading enzymes at ensiling on the fermentation and in situ degradation of grass and legume silages. Primary growths of Italian ryegrass (Lolium multiflorum Lam) and lucerne (Medicago sativa L) were wilted and ensiled in laboratory-scale silos with or without enzymes. Silages were opened at 2, 5, 15 and 45 days after storage; the fermentation quality and the contents of cell wall components (NDF, ADF, ADL) were determined. The 45 day silages were subjected to in situ incubation experiments, and the kinetics of DM and NDF degradation was estimated. The enzyme treatment enhanced the lactic acid production (P < 0.01) and reduced the pH value (P < 0.01) of both Italian ryegrass and lucerne silages. The contents of cell wall components, however, were not affected by enzymes, except for NDF of Italian ryegrass silage. The in situ incubation experiments revealed that added enzymes increased the rapidly degradable DM (P < 0.01) and appeared to decrease the rate of degradation of DM and NDF of Italian ryegrass silage. The rapidly degradable DM was not altered when lucerne was treated, but the rate of degradation of NDF was significantly reduced (P < 0.05). These results suggest that although added cell wall-degrading enzymes could improve the preservation of grass and legume silages, the effects on ruminal degradation may be different according to the herbage treated. Enzymatic hydrolysis during ensilage may be restricted to easily digestible cell walls, leaving relatively less digestible components that would be retained in treated silages. © 1999 Society of Chemical Industry     

Characterisation of peptides in silages made from perennial ryegrass with different silage additives

The effects of applying either formic acid (5.4 g kg⁻¹), a mixture of formic acid (2.7 g kg⁻¹) and formaldehyde (1.5 g kg⁻¹, 81 g kg⁻¹ herbage crude protein) or two concentrations of a cysteine peptidase inhibitor, cystamine (5 or 50 g kg⁻¹), to perennial ryegrass (Lolium perenne) on the nitrogen (N) distribution of the resulting silages were investigated, with emphasis on changes in concentration, composition and molecular weight of silage peptides. Herbage (156 g dry matter kg⁻¹ and 141 g water‐soluble carbohydrate kg⁻¹ dry matter) was ensiled in triplicate in laboratory silos for 100 days. Formic acid and the formic acid/formaldehyde mixture reduced soluble non‐protein N and ammonia N concentrations (P < 0.01); in addition, formic acid increased peptide N concentrations (P < 0.05). Cystamine at 50 g kg⁻¹ reduced ammonia N concentrations (P < 0.01) and increased peptide N concentrations (P < 0.05), but when applied at 5 g kg⁻¹ had little effect. Gel filtration of silage extracts on Sephadex G‐25 suggested that a small proportion (0.06–0.11 g kg⁻¹ peptide N) of silage peptides had a chain length of 7–9 amino acids, but remaining peptides were smaller with chain lengths of 2–6 amino acid residues. Amino acid analysis of silage peptides indicated that additive treatment had little effect on peptide amino acid composition but that peptides with a chain length of 7–9 amino acids contained lower proportions of isoleucine and arginine. © 2000 Society of Chemical Industry     

Effect of long-term application of animal slurries to grass on silage feeding quality for sheep

The effect of slurry type (pig or cow) and use of a bacterial silage inoculant, was assessed on herbage from long-term slurry plots ensiled in pilot-scale (0·7 tonne) silos. Silage was fed to sheep to assess digestibility and metabolisable energy content. The latter was measured by direct calorimetry in a modified cattle respiration chamber. Non-inoculated slurry-treated silages had poorer fermentation quality than inoculant-treated silages (P < 0·001) and silages treated with cow slurry had poorer fermentation quality than those treated with pig slurry (P < 0·001). Digestibility values for different components of the silages showed few differences. Energy digestibility values of pig slurry-treated silages were lower (P < 0·05) than for cow slurry-treated silages. Methane production from all animals in the experiment was comparatively low at 5·97–6·74% of gross energy intake. Metabolisable energy contents of the cow slurry-treated silages were higher than pig slurry-treated silages (P < 0·05) and the ME contents of inoculant treated silages were higher than of non-inoculated silages (P < 0·001). Thus, treatment of slurry-treated silages with bacterial inoculant enhanced fermentation quality and ME contents. The effect of slurry type on fermentation quality and feeding value was ambiguous; cow slurry-treated silages exhibiting poorer fermentation quality but higher ME contents than equivalent pig slurry-treated silages. © 1998 Society of Chemical Industry.     

Effects of Silage Fermentation and Post-ruminal Casein Supplementation in Lactating Dairy Cows: 2—Energy Metabolites and Plasma Amino Acids

Four cows were used in a 4×4 Latin square design with a 2×2 factorial arrangement of treatments to examine the effects of the extent of silage fermentation and post-ruminal casein infusion on the arterial concentrations and mammary arterial–venous (A–V) difference of energy-yielding nutrients and plasma amino acids. Of the two silages one was preserved with formic acid (FA-silage) and the other with an inoculant of lactic acid bacteria (LAB-silage). Both silages were given ad libitum with 8 kg day^-1 of barley, without or with duodenal casein infusing (400 g day^-1). Blood was sampled from the coccygeal vessel and milk vein. FA-silage less fermented than LAB-silage as indicated by higher concentration (g kg^-1 dry matter) of water soluble carbohydrates (178 vs 68) and lower concentration of lactic acid (32 vs 147). Plasma concentration of glucose was lower (P<0·05) and concentrations of essential amino acids (P<0·001) and blood β-hydroxybutyrate (BHB) (P<0·01) were higher with FA-silage than with LAB-silage. There was a strong linear relationship between arterial concentration and mammary A–V difference of blood metabolites, except BHB, and amino acids. The relationship between arterial concentration and mammary A–V difference of glucose was different between the silages. Mammary extraction rates of glucose, BHB, histidine, leucine and lysine were affected by their arterial concentrations. The interaction between silage fermentation and casein infusion was significant (P<0·05) in arterial concentration of branched-chain amino acids, the increase being greater with FA-silage than with LAB-silage. The results suggest that the supply of glucose may limit milk synthesis in cows given restrictively fermented grass silage and barley, whereas the supply of amino acids may be more limiting with extensively fermented silages. It is further suggested that the mammary gland has a capacity to adapt it's efficiency of nutrient uptake according to the supply and mammary demand of nutrients. © 1997 SCI.     

Sodium benzoate,potassium sorbate and sodium nitrite as silage additives

BACKGROUND: The hygienic quality of silage is important for animal health, animal production and food quality. The aim of this study was to evaluate the effect of five silage additive mixtures on yeast, mould, and clostridia growth and other silage quality criteria. The additives, composed of sodium nitrite, sodium benzoate and/or potassium sorbate, were used to treat a grass forage crop before ensiling. The silages were compared with untreated silage and silages treated with two commercial additives: Promyr NF (PNF), which is based on formic and propionic acid, and Kofasil Ultra (KU), a mixture of sodium nitrite, sodium benzoate, sodium propionate and hexamine. RESULTS: All tested additives significantly (P < 0.001) reduced butyric acid and ammonia‐N formation in low‐dry‐matter (DM) silages compared to the control. Only KU and the mixtures of 600 g sodium nitrite, 250 g sodium propionate, 750 g sodium benzoate (A1) and 250 g sodium nitrite with 1000 g sodium benzoate and 500 g potassium sorbate (A5) ton^?1 of fresh forage were found to reduce (P < 0.001) the presence of clostridia spores in low‐DM silages. In high‐DM silages, treatments A1, A5 and A2 (250 g sodium nitrite and 1000 g sodium benzoate) contained less (P < 0.02) yeast than the control and PNF, but not KU. All treated silages were aerobically stable. The concentrations of nitrate‐N in all silages and nitrite‐N in low‐DM were below the threshold level for feed at the end of storage. CONCLUSIONS: The additive mixtures A1 and particularly A5 improved silage quality at least to the same extent as commercial products, even though they contained no hexamine and less nitrite. Copyright © 2009 Society of Chemical Industry     

Effect of oregano and thyme essential oils on the microbiological and chemical quality of refrigerated (4 °C) ready‐to‐eat squid rings

The efficacy of oregano and thyme essential oils (OEO and TEO, respectively) in the quality retention of a refrigerated (4 °C) squid (Loligo vulgaris) ring ready‐to‐eat (RTE) product was studied. Essential oils were added at different concentrations to the coating medium during processing. An inhibitory (P < 0.05) effect of OEO on the microbial activity (aerobes, anaerobes, Enterobacteriaceae, psychrotrophs) of the squid rings was observed, with a more pronounced effect as OEO concentration increased. The addition of OEO also led to an inhibitory (P < 0.05) effect on lipid oxidation, as determined by peroxide, thiobarbituric acid‐reactive substance and interaction compound formation; however, no effect (P > 0.05) of the OEO concentrations on lipid oxidation development was detected. The addition of TEO did not lead to an inhibitory effect (P > 0.05) on the microbial activity of the refrigerated RTE squid, although a slight inhibitory (P < 0.05) effect on lipid oxidation was observed in the batches including the higher TEO concentrations.     

Ensilage as a means of reducing the concentration of cyanogenic glycosides in the pods of Acacia sieberiana and the effect of additives on silage quality

Cyanogenic glycosides are anti‐nutritional components capable of liberating hydrogen cyanide, a respiratory poison that has been reported to be responsible for the death of livestock that browse some Acacia species containing these compounds. The objective of the study was to improve the nutritive value of the pods of Acacia sieberiana by reducing their contents of cyanogenic glycosides through ensiling, and to examine the influence of various levels of added molasses and urea on the aerobic stability of the silage. In experiment 1, laboratory silages, prepared by mixing ground pods with water in two ratios (60:40 and 40:60 w/w pod material:water), were put into 250 ml polythene bottles, ensiled for 4, 7, 14, 21, 28 or 35 days and analyzed for cyanide. In experiment 2, silages prepared as described above but using only one of the ratios (40:60), and with the addition of molasses (0, 30 or 60 g kg^?1) and urea (0, 2.5 or 50 g kg^?1) were included in a 3 × 3 factorial design, to study the effects of these additives on the stability of the silage. The period of ensilage was 14 days. In experiment 3, the concentrations of molasses and urea were modified to 0, 45 or 90 g kg^?1 and 0, 7.5 or 15 g kg^?1, respectively, and the period of ensilage was extended to 45 days. The parent material contained 130.6 mg CN kg^?1 DM and ensiling the material for 35 days reduced the concentration to 18.1 mg CN kg^?1 DM. Moisture content at ensiling significantly (P < 0.001) affected the concentration of cyanide in the stored silages. Silages opened after 14 days were unstable irrespective of the use of additives. However those with combined urea and molasses exhibited a slow rate of deterioration and low fungal counts. Extending the period of ensiling to 45 days improved the aerobic stability of all the silages. The addition of urea significantly (P < 0.001) increased the pH, crude protein content, gross energy and fermentation acids while molasses treatment increased (P < 0.001) the lactic acid and ash content of the silages. Ensiling ground pods for 45 days was enough to reduce the cyanide content to non‐toxic levels and produced a silage which was aerobically stable, while the inclusion of additives further improved the quality of the silages. Copyright © 2004 Society of Chemical Industry     

Ensiling characteristics and aerobic stability of direct‐cut and wilted grass silages inoculated with Lactobacillus casei or Lactobacillus buchneri

Two experiments were conducted to study the effects of wilting and inoculating Lactobacillus casei or Lactobacillus buchneri on the fermentation and aerobic stability of grass silages. Chopped Italian ryegrass (IR) and Festulolium (FE) were ensiled with or without wilting and added L casei (>10⁶ cfu g^?1 fresh matter (FM)) or L buchneri (>10⁶ cfu g^?1 FM). Silos were opened after 120 days and microbial counts, fermentation products and aerobic stability were determined. Addition of L casei increased lactic acid and decreased acetic acid and dry matter loss regardless of wilting and forage species. Inoculation of L buchneri decreased lactic acid and increased acetic acid and 1,2‐propanediol, while the effects appeared greater in direct‐cut than in wilted grass silages. Although 1,2‐propanediol accumulated in FE silage, the diol was degraded further to propionic acid and 1‐propanol in IR silage. The activity of 1,2‐propanediol degradation was lowered when IR was wilted prior to ensiling; 1,2‐propanediol remained and the production of propionic acid and 1‐propanol was less than one‐third of that in direct‐cut silage. Regardless of forage species, addition of L buchneri increased dry matter loss compared with the untreated control, whereas the loss was not significant in wilted silages. Ammonia production was increased by L buchneri in direct‐cut but not in wilted silages. No heating was observed with or without inoculation in direct‐cut IR silage after exposure to air. Other silages were deteriorated when L buchneri was not inoculated, while the spoilage was accelerated when L casei was added to FE. Copyright © 2005 Society of Chemical Industry     

Effects of wilting and mechanical conditioning on proteolysis in sainfoin (Onobrychis viciifolia Scop) wilted herbage and silage

Ensiling legumes allows conservation of high‐quality forage. However, severe protein degradation occurs during ensiling of legumes. A field study was carried out in 1999 on sainfoin (Onobrychis viciifolia Scop) to investigate the effects of wilting and mechanical conditioning on proteolysis in wilted herbage and silage. The herbage was cut with both a rubber roll conditioning machine (C) and with a mower without conditioner (U). It was wilted in the field to three dry matter (DM) levels (220, 330 and 440 g kg^?1) and ensiled in laboratory glass silos. The herbages and the silages were analysed for ensilability characteristics, fermentation quality and nitrogen fractions. During wilting the non‐protein nitrogen (NPN) values increased (p < 0.05) in both U and C treatment. The free amino acid (free AA) values increased (p < 0.05) from 2.4 to 12.9 and from 2.4 to 7.2 mol kg^?1 total nitrogen, in the U and C treatments, respectively. Low wilted silages (DM content <320 g kg^?1) underwent butyric acid fermentation and extensive proteolysis in both treatments, with lower (p < 0.05) NPN and free AA values in the C treatment. Mechanical conditioning may limit protein breakdown and catabolism of some essential amino acids by reducing the field wilting time in both sainfoin wilted herbage and silage. Copyright © 2004 Society of Chemical Industry     

Effects of varying degrees of synchrony of energy and nitrogen release in the rumen on the synthesis of microbial protein in cattle consuming grass silage

The effect of the degree of synchrony in the ruminal release of energy and nitrogen on microbial protein synthesis (MPS) was examined in cattle consuming grass silage (7.9 kg DM day⁻¹) and a supplement of 1 kg day⁻¹ of sucrose given as an intraruminal infusion. The sucrose was infused in three different patterns to induce varying degrees of synchrony of energy and nitrogen release. Four non‐lactating cows received four experimental treatments in a 4 × 4 Latin square design with periods lasting 14 days. The treatments were (1) the basal diet of silage alone given in two equal meals each day at 10.00 and 22.00 h (BASAL), supplemented with (2) 1.0 kg sucrose given as a continuous infusion (CONT), (3) 1.0 kg sucrose given as two 6‐h infusions starting at 10.00 and 22.00 h (SYNC) and (4) 1.0 kg sucrose given as two 6‐h infusions starting at 16.00 and 04.00 h (ASYNC). The different patterns of infusing the sucrose altered (P < 0.05) the pattern of variation in ruminal concentrations of ammonia and the molar proportions of acetic and butyric acids at times during the interval between meals but none of the sucrose treatments resulted in any increase in the ruminal concentration of lactic acid. All sucrose treatments increased (P < 0.05) MPS relative to BASAL by, on average, about 23 g day⁻¹. The increase in MPS for the SYNC and ASYNC treatments were identical at 20 g kg⁻¹ sucrose. It is concluded that synchronising the rates of ruminal release of energy and nitrogen had no effect on MPS. © 1999 Society of Chemical Industry     

Supplementing fresh pasture with maize,lotus, sulla and pasture silages for dairy cows in summer

A trial was conducted to compare benefits obtained from feeding four types of silage. There were two silages that contained condensed tannins (CT)—lotus (Lotus corniculatus) and sulla (Hedysarum coronarium)—maize silage or traditional ryegrass pasture silage, all fed at 5 kg dry matter (DM) cow^?1 day^?1 with restricted pasture (RP). Cows on the RP (control) treatment and those fed the silage treatments were offered an allowance of 25 kg pasture DM cow^?1 day^?1, while the full pasture (FP) cows were offered 50 kg pasture DM cow^?1 day^?1. Silage supplementation increased both DM intake and milk yield compared with cows given RP only. Cows on the lotus silage supplement and the FP treatment had significantly higher milk production than the other silage supplemented cows (P < 0.001). For cows given lotus silage, the high milk yield was probably due to a combination of the higher nutritive value of the silage and possibly to the protein‐sparing effects of the lotus condensed tannins because the total DM intake of cows fed the lotus silage was the same as that of cows given the pasture and maize silages (P > 0.25). The high milk yield of the FP treatment was mainly a result of the cows having a higher intake of pasture than cows on all the other treatments. This study demonstrated the potential benefit of silage supplementation, particularly with lotus silage, for increased milksolids yield in summer when low pasture growth rates and quality may otherwise limit production. Copyright © 2006 Society of Chemical Industry     

Effects of Silage Fermentation and Post-ruminal Casein Supplementation in Lactating Dairy Cows: 1—Diet Digestion and Milk Production

Two silages were prepared from the first-cut sward of timothy-meadow fescue and wilted to a dry matter (DM) content of 300 g kg^-1. One was ensiled with the addition of a formic-acid-based additive (4 litres formic acid (FA) per tonne) and the other with the addition of a bacterial inoculant (LAB) at a rate of 5×10⁶ colony forming units g^-1. Both silages were well preserved, but the extent of fermentation was greater in LAB-silage than in FA-silage as indicated by a lower concentration of water soluble carbohydrates (68 vs 177 g kg^-1 DM) and a higher concentration of lactic acid (147 vs 32 g kg^-1 DM). Four Ayrshire cows were used in a 4×4 Latin square experiment with 21-day periods to study the effects of silage fermentation and postruminal casein supplementation on silage intake, nutrient supply and milk production. The four treatments were FA-silage without casein (FA-0), LAB-silage without casein (LAB-0), FA-silage with casein (FA-C) and LAB-silage with casein (LAB-C). Both silages were given ad libitum with 8 kg day^-1 of barley without or with 400 g day^-1 of casein infused into the duodenum. Organic matter digestibility was lower (0·723 vs 0·753; P<0·01) for FA-silage than for LAB-silage. Cows offered FA-silage had a higher molar proportion of acetate and a lower proportion of propionate in ruminal fluid than cows offered LAB-silage. Microbial protein synthesis estimated from the output of purine derivatives in urine was greater (288 vs 260 g N day^-1; P<0·05) for cows given FA-silage compared with LAB-silage. Feeding LAB-treated silage tended (P<0·10) to decrease silage DM intake compared with FA-treated silage (10·61 vs 11·77 kg DM day^-1). Silage composition did not affect significantly milk yield or milk composition. Casein infusion increased milk yield (25·1 vs 27·1 kg day^-1; P<0·05), milk protein content (32·4 vs 33·8 g kg^-1; P<0·05) and protein yield (808 vs 905 g day^-1; P<0·01). The responses were similar for both silages. © 1997 SCI.     

Effects of California chaparral plants on in vitro ruminal fermentation of forage and concentrate diet

BACKGROUND: The combustible nature of chaparral plants has been attributed to the presence of secondary compounds such as phenolic acids, flavonoids and essential oils, among others. However, the implication of the antimicrobial properties of secondary compounds of chaparral in modulating rumen microbial metabolism has not been determined. The effects of 11 chaparral plants on rumen microbial fermentation were assessed in an in vitro batch culture fermentation fed a barley silage:barley grain‐based low concentrate (LC) and high concentrate (HC) diets. RESULTS: With LC, gas production [g dry matter (DM) incubated] and DM disappearance (DMD) were unaffected by Adenostoma fasciculatum, Ceanothus cuneatus, Baccharis pilularis or Eriodictyon californicum, but all plants except C. cuneatus decreased (P < 0.05) CH₄ production. With HC diet, all species except A. fasciculatum decreased (P < 0.01) total gas produced. Total volatile fatty acids (VFA) produced, molar proportions of acetate, propionate and butyrate, and the acetate:propionate (A:P) ratio were unaffected by chaparral addition to both HC and LC diets. Increased concentrations of A. fasciculatum and E. californicum decreased (linear; P < 0.05) fermentability and productions of CH₄ and NH₃‐N. CONCLUSION: Among all chaparral species investigated A. fasciculatum and E. californicum added as 10% of LC diet showed some potential to exert beneficial effects on rumen microbial fermentation. © Her Majesty the Queen in Right of Canada 2012     

Effect of fibrolytic enzymes and an inoculant on in vitro degradability and gas production of low‐dry matter alfalfa silage

BACKGROUND: The objective of this study was to investigate the effect of polysaccharide‐degrading enzymes (a cellulase and a xylanase) alone or in a combination with a bacterial inoculant on fermentation parameters and in vitro degradability and gas production of low‐dry matter (DM) alfalfa silage. First cut alfalfa (Medicago sativa L.), harvested at about 5% bloom stage [260 g kg^?1 dry matter (DM)] was ensiled in laboratory‐scale silos without preservatives or preserved with formic acid, a cellulase (Cell), a xylanase, a cellulose/xylanase enzyme combination (Cell/Xyl), a lactic acid bacteria‐based inoculant (Inoc), and a mix of Inoc and Cell (Inoc/Cell). Triplicate silos were opened on days 1, 3, 7, 15 and 60. RESULTS: Silage pH and ammonia N and total free amino acids concentrations were the lowest (P < 0.05) for the formic acid silage. Inoc and Inoc/Cell produced the highest (P < 0.05) lactate concentration in the 60‐day silage. In vitro degradability of silage DM was not affected (P = 0.998) by treatment, but amylase‐treated neutral detergent fiber degradability was increased (P < 0.05) by formic acid. Compared with the control (51.3 mL 100 mg^?1 silage DM), all treatments except Cell/Xyl increased (P < 0.001) the 24 h cumulative gas production. CONCLUSIONS: Overall, enzyme and lactic acid bacteria‐based preparations had minor effects on silage fermentation in this experiment. The increased cumulative gas production indicates some preservation or liberation of fermentable organic matter with most treatments tested. It is not clear, however, to what extent this effect would impact silage ruminal degradability in vivo. Copyright © 2008 Society of Chemical Industry     

Trichoderma enzymes promote Fibrobacter succinogenes S85 adhesion to,and degradation of,complex substrates but not pure cellulose

The effects of an enzyme preparation from Trichoderma longibrachiatum (TE) on adhesion and growth of the fibrolytic rumen bacterium Fibrobacter succinogenes S85 was studied to gain a better understanding of the action of feed enzyme additives on fibre digestion by ruminants. Adhesion experiments were performed on crystalline cellulose, corn silage and alfalfa hay. Adhesion of F succinogenes to cellulose was negatively related to the concentration of TE (p < 0.05). At the highest concentration used, TE reduced adhesion to cellulose from 65 to 39%. For corn silage and alfalfa hay, TE stimulated adhesion at low levels (p < 0.05) but this effect was lost at higher levels. Culture experiments were performed on crystalline cellulose and corn silage. The presence of TE in media containing cellulose failed to increase substrate disappearance or gas production although it increased numbers of non‐adherent bacteria (p < 0.05). When corn silage was used, the addition of TE increased NDF disappearance (p < 0.05) at 24 and 48 h (33 and 52% in controls versus 53 and 65% in TE treatments). Growth rate and gas production were also stimulated (p < 0.05). We conclude that, for cellulose, the hydrolytic enzymes in TE obstructed available binding sites decreasing bacterial adherence. Fibrobacter succinogenes digested cellulose efficiently and addition of exogenous cellulases did not further increase substrate disappearance. However, for complex plant substrates, low concentration of TE increased bacterial adhesion and plant (corn) fiber degradation. For the Department of Agriculture and Agri‐Food, Government of Canada, © Minister of Public Works and Government Services Canada 2004. Published for SCI by John Wiley & Sons, Ltd.     

The effect of inoculation and additives on D(−)‐ and L(+)‐lactic acid production and fermentation quality of guineagrass (Panicum maximum Jacq) silage

Two experiments were carried out to study the influence of storage time, glucose and urea additions ( Experiment 1 ) and lactic acid bacteria inoculation with and without glucose addition ( Experiment 2 ) on the production of lactate isomers and fermentation quality of guineagrass (Panicum maximum Jacq) silage. All silages in both experiments were well preserved, as indicated by lower pH and little or no butyric acid. In Experiment 1 , addition of glucose or urea did not significantly affect the pH of silages (P > 0.05). Urea addition tended to reduce acetic acid content and greatly increased NH₃ − N content. L (+)‐Lactic acid was produced predominantly in the first 3 days of ensiling, but D (−)‐lactic acid increased gradually until 1 month after ensiling. Thereafter all silages became stable. In Experiment 2 , inoculation of Lactobacillus casei or L rhamnosus with or without glucose reduced D (−)‐lactic acid and increased L (+)‐lactic acid of silages. The proportions of L (+)‐lactic acid in these silages were higher than 80% of total lactic acid. L plantarum alone or in combination with glucose promoted D (−)‐lactic acid production and decreased the proportion of L (+)‐lactic acid. Glucose addition alone tended to reduce the proportion of L (+)‐lactic acid in both experiments. © 2000 Society of Chemical Industry