The effects of wet sorghum distillers' grains inclusion on napiergrass silage quality

This paper studies different amounts of wet sorghum distillers' grain (WSDG) for inclusion in napiergrass silage for silage fermentation. Napiergrass was harvested, chopped and mixed in four different ratios with WSDG. The ratio of WSDG to napiergrass on a dry matter basis was 0, 20, 40 and 60% respectively in four different dietary treatments. These materials were ensiled in 60 laboratory mini‐silos, 45 cm in height and 21 cm in radius. The napiergrass was put into 56 containers, which included two replicates for each of the four treatments. Each treatment utilised seven silage containers for each sampling time. Every two replicate mini‐silos were opened and sampled for analysis at 0, 1, 2, 4, 8, 16 and 32 days after ensiling respectively. One silage container from each treatment was installed with a remote‐controlled electronic thermometer to record temperature changes. Sample analyses included determination of pH, titratable acidity, buffering capacity, neutral detergent fibre (NDF), acid detergent fibre (ADF), crude protein, ammonia nitrogen, lactic acid, volatile fatty acids (VFA), water‐soluble carbohydrates (WSC), dry matter (DM) and ash. The results of the silage characteristics at the end of the 32 day ensilage showed that the pH value of the 40% WSDG group was significantly lower (P < 0.05) than that of the other treatment groups. The titratable acidity, buffering capacity and water‐soluble carbohydrates of the control group were significantly lower (P < 0.05) than those of the other groups. Lactic acid production by the 20% WSDG group was significantly higher (P < 0.05) than that of the other treatment groups. Lactic acid production in the control was significantly lower (P < 0.05). The ammonia N concentration of the total N of the 60% WSDG group was significantly lower (P < 0.05) than that of the other groups. The Flieg score of the control was 85, the 20% group was 93, the 40% group was 95 and the 60% group was 91. © 2000 Society of Chemical Industry     

The nutritive value for ruminants of thin stillage and distillers' grains derived from wheat,rye, triticale and barley

A study was conducted to determine nutrient degradabilities of thin stillages and distillers' grains derived from wheat‐, rye‐, triticale‐ and barley‐based ethanol production. In vitro protein degradabilities of wheat, rye, triticale and barley thin stillages were determined using a protease enzyme assay. One ruminally fistulated cow was used to determine ruminal nutrient degradabilities for wheat, rye, triticale and barley distillers' grains. Results of the in vitro study showed that the soluble protein fraction was highest for rye thin stillage and lowest for barley thin stillage. The degradation rate of the slowly degradable protein fraction was higher for wheat and triticale thin stillage than rye thin stillage and was higher for rye than barley thin stillage. Effective degradability of crude protein followed the order rye (659 g kg⁻¹) > triticale (632 g kg⁻¹) > wheat (608 g kg⁻¹) > barley (482 g kg⁻¹) thin stillage. Ruminal degradability of dry matter was highest for rye and lowest for barley distillers' grains. Ruminal degradability of dry matter was also higher for wheat than triticale distillers' grains. Crude protein from barley distillers' grains had a lower ruminal degradability relative to crude protein from wheat and rye distillers' grains. Ruminal degradability of neutral detergent fibre was highest for rye distillers' grains (470 g kg⁻¹), intermediate for wheat and triticale distillers' grains (average 445 g kg⁻¹) and lowest for barley distillers' grains (342 g kg⁻¹). It was concluded that thin stillage and distillers' grains derived from barley had a lower nutritive value for ruminants compared with those derived from wheat, rye and triticale. © 2000 Society of Chemical Industry     

乙醇-沼气双发酵耦联工艺对酒糟蛋白饲料的影响

乙醇-沼气双发酵耦联工艺可有效解决玉米乙醇生产过程存在的能耗大、废水处理成本高的问题。作者研究了耦联工艺对玉米乙醇生产过程的主要副产物酒糟蛋白饲料的影响。结果表明,与传统的干磨工艺比较,耦联工艺所得的酒糟蛋白饲料含有较高质量分数的蛋白质和氨基酸,较低质量分数的盐,因此拥有更高的营养价值。利用电子鼻和气质联用对酒糟蛋白饲料气味进行分析,发现循环批次所得酒糟蛋白饲料与第一批在气味上表现出一定的差异,但是不会影响家畜的食用。     

Investigation of ammonium lactate supplementation on fermentation end products and bacterial assimilation of nitrogen in dual-flow continuous culture

Supplements investigated throughout the present study are produced by fermenting lactose that is present in whey to lactate, yielding products differing in ammonium relative to lactate concentrations and in physical form (liquid or dry). Trials 1 and 2 investigated Lacto-Whey (LW; Fermented Nutrition Corp., Luxemburg, WI) and GlucoBoost (GB; Fermented Nutrition Corp.), respectively, using dual-flow continuous culture systems (n = 4), each with a 4 × 4 Latin square design. A greater proportion of nonprotein nitrogen was present in GB than in LW. In trial 1, the treatment with LW was isonitrogenously dosed against soybean meal (SBM) as a control (no LW) and factorialized with either a wheat- or corn-based concentrate (55% inclusion rate, dry matter basis). We hypothesized that LW would increase propionate production and that the combination of +LW with wheat would increase bacterial assimilation of NH₃-N into cellular N. No differences were observed for total volatile fatty acid (VFA) production per day. However, treatment × time interactions revealed that +LW increased lactate concentration at 0, 0.5, and 1 h and tended to increase molar percentage of propionate at 1 and 1.5 h postfeeding, documenting the immediate availability of lactate converted to propionate in the +LW treatments. The main effect of corn increased the proportion of bacterial N derived from NH₃-N. Trial 2 was designed to investigate GB; isonitrogenous treatments included an SBM control, crystal GB, liquid GB (LGB), and LGB with yeast culture, which were dosed twice daily. We hypothesized that GB would increase propionate production and bacterial assimilation of NH₃-N; the combination of LGB and yeast culture was expected to have a positive additive effect, yielding the greatest VFA production and bacterial NH₃-N assimilation. No differences were observed for total VFA production; however, LGB decreased molar percentage of acetate and increased propionate and butyrate molar percentages. There were no differences in non-NH₃-N flow or microbial N flow. Under the conditions of our studies, lactate in LW and GB was fermented extensively to propionate, and microbial protein synthesis in these treatments was comparable with that in SBM controls.     

Effects of BioChlor and Fermenten on microbial protein synthesis in continuous culture fermenters

Meta analysis models were constructed from a data-set of 15 continuous culture fermenter trials and 118 observations on studies with either BioChlor (n = 23 observations) or Fermenten (n = 95) included at 10 and 3%, respectively, of dietary dry matter (DM) to evaluate effects of the ingredients BioChlor and Fermenten (B/F) on rumen function. Digestibility of crude protein was significantly increased by 11% with B/F treatment. This was reflected in significant increases in digestibility of DM and organic matter (OM) by 3.6 and 7.9%, respectively. Increased amounts of sugar in the diet in the presence of B/F tended to reduce digestibility of non-structural carbohydrates (NSC); however, the net effect on NSC digestion was small. There was no effect of treatment on most individual volatile fatty acids (VFA) or total VFA production. Propionate production, however, was significantly reduced in treated fermenters. The main effect of B/F as well as of starch and soluble fiber when combined with the treatment was to increase propionate production; however, the interaction between B/F treatment and sugar decreased propionate production markedly, resulting in a net decrease. The acetate-to-propionate ratio increased by 6% with B/F, largely as a result of the decrease in propionate. Production of nonammonia nitrogen was 1% less in B/F-treated fermenters, and interactions between treatment and starch, sugar, or soluble fiber were significant. Treated fermenters produced 15.7% more microbial nitrogen, in association with a significant 37% increase in rumen protein digestion. Interactions between treatment and starch, soluble fiber, or sugar influenced these results. The interaction of B/F and sugar resulted in a decrease in undegradable protein N and an increase in microbial nitrogen production. Ammonia nitrogen concentrations were increased by 24.6% in treated fermenters. Efficiency of microbial nitrogen production from DM, OM, or carbohydrate was significantly increased by B/F. Sugar content increased efficiency of microbial protein production/kg of OM digested or carbohydrate digested in the presence of treatment by >10 times the increase that was attributable to the interaction of treatment with starch. Treatment with B/F reduced moles of VFA produced/kg of microbial nitrogen produced by 16%. This effect was also substantially influenced by interactions between B/F and sugar. If the fermenter results are representative of those in vivo, milk production responses to treatment with B/F will depend on amounts of starch, soluble fiber, and, particularly, sugar in diets. Milk production responses will also depend on the quality of protein in the diet and the comparative benefit that increased flux of microbial nitrogen provides. Increased digestibility of OM should allow additional ruminant production benefits.     

Maintenance of rumen protozoa populations in a dual outflow continuous fermenter

Using a 2^5–2 fractional factorial design, five factors were screened for their ability to promote rumen protozoa growth in a dual outflow fermenter and on their influence on fermentation. The tested factors were the addition of bovine serum (BS, 20 ml litre⁻¹) and of a 100 g litre⁻¹ yeast extract solution (20 ml litre⁻¹) to artificial saliva, the addition of diethystilbestrol (15 mg day⁻¹) to fermentation broths, the reduction of shear stresses by lowering the stirring speed from 260 rpm to 230 rpm, and the improvement of ciliate sequestration by the use of a polyurethane foam belt. In the fermentors, the ciliate population density ranged from 10 μl⁻¹ to 58 μl⁻¹. The genus Isotricha was rarely observed, with a population density estimated at <0·7 μl⁻¹ while Dasytricha was not maintained. All the experimental factors markedly influenced total protozoa numbers. Lowering the stirring speed was the sole beneficial treatment. Nutritional supplements, in particular BS, were all detrimental to Entodinium. Their association was characterised by a significant antagonism. The population size of Polyplastron and Eudiplodinium was lowered only by BS addition, possibly through the changes induced in the fermentation pattern. ©1997 SCI     

THE FATE OF LIVE BREWERS' YEAST SLURRY IN BOVINE RUMEN FLUID

Live brewers' yeast slurry was incubated under carbon dioxide at 27°C and 39°C in 0·1% peptone solution and in bovine rumen fluid which had been clarified by removal of the population of bacteria and protozoa normally present. Numbers of viable yeast in both media remained constant for 12 h at 27°C; at 39°C loss in viability was 81 % in peptone and 94% in rumen fluid during the same period. When glucose was added to clarified or unclarified rumen fluid containing yeast slurry and incubated for 6 h at 39°C, ethanol was produced. Ethanol production was prevented if the slurry was treated with heat or chemical preservatives before addition to the rumen fluid. Unclarified rumen fluid from a steer fed a brome-alfalfa hay-grain ration contained 10²–10³ yeasts and moulds per ml. The results suggested that the feeding of live brewers' yeast slurry to ruminants could result in ethanol toxicity if fermentable carbohydrate were also present, though many of the yeast cells would succumb to heat inactivation at normal rumen temperatures. This risk could be eliminated by prior treatment of the slurry with heat or chemical preservatives.     

固定化酵母用于白酒丢糟降解液乙醇发酵的研究

为了提高白酒生产中废弃物的资源化利用效率,探讨了利用固定化酵母实现丢糟降解液连续发酵生产乙醇的工艺。采用固定化的LR3.1300酵母菌株(Saccharomyces sp)进行丢糟降解液的批次和连续乙醇发酵试验。批次发酵试验结果显示,固定化酵母在白酒糟降解液与葡萄糖混合液中发酵的底物利用和产酒效率都较高。在固定化酵母连续发酵中,当固定化酵母液为60 mL,降解糖液进料速度为15 mL/h时,还原糖利用率为83.7%,流出液酒精度达到了3.97%vol,乙醇发酵的效率与前期的游离酵母发酵相比提高了43%。     

浓香型白酒酒糟中淀粉的提取

以浓香型白酒酒糟为原料,研究了酶法、碱法、SDS法对淀粉纯度的影响。研究表明:酶法提取的酒糟淀粉纯度最高;同时在单因素试验的基础上,根据Box-Behnken中心组合试验设计原理,采用三因素三水平响应面分析法对酒糟淀粉提取工艺进行优化研究,确定酶法提取酒糟淀粉的最佳工艺参数:酶添加量为2%,pH3.5,酶解温度40℃。该条件下得到酒糟淀粉纯度为70.23%。酶法制得的酒糟淀粉理化特性为:扫描电镜图片显示该提取方法未对淀粉颗粒造成损伤;与原淀粉相比,晶体类型从A型变为A+V型,这可能与酿酒工艺有关,而与提取方法无关。     

Effect of Yeast Culture Supplement on Ruminal Microbial Populations and Metabolism in Buffalo Calves Fed a High Roughage Diet

The effect of Saccharomyces cerevisiae yeast culture (YC, Yea-Sacc 1026) as a supplement to the high-roughage diet of buffalo calves on the rumen microbial populations, fermentation pattern and in sacco dry matter disappearance of dietary constituents was examined. A control group was fed a diet consisting of, on a dry matter basis, 2·12 kg bajra (Pennisetum typhoides) hay and 0·45 kg groundnut cake per day per calf, while the treatment group had the same diet plus 5 g YC. After feeding for 6 weeks, inclusion of YC was stopped and both groups were given the control diet for 2 weeks. At week 4 the pH in the rumen fluid (RF) was significantly higher (P<0·05) up to 6 h post-feeding in the treatment group compared with the control group. The concentrations of total, total viable and cellulolytic bacteria were increased by 41·0 (P<0·05), 33·5 and 57·4% (P<0·01), respectively, with YC supplement. The concentration of total volatile fatty acids (P<0·05), particularly at 4 h post-feeding (P<0·01) and acetate (P<0·01) and acetate to propionate ratio (P<0·05) were higher in the treatment compared with the control group. On YC supplementation, the concentration of NH₃-N was decreased (P<0·05) while that of TCA-precipitable protein in RF was marginally but non-significantly increased. Withdrawal of YC from the diet reversed these effects and the rumen variables returned to values close to control levels after 2 weeks. The in sacco dry matter disappearance of dietary components was higher in the treatment compared with the control group, particularly during the first 24 h of incubation. © 1997 SCI.     

Conditions stimulating neutral detergent fiber degradation by dosing branched-chain volatile fatty acids. I: Comparison with branched-chain amino acids and forage source in ruminal batch cultures

Three experiments assessed branched-chain volatile fatty acid (BCVFA) stimulation of neutral detergent fiber (NDF) disappearance after 24 h of incubation in batch cultures derived from ruminal fluid inocula that were enriched with particulate-phase bacteria. In experiment 1, a control was compared with 3 treatments with isomolar doses of all 3 BCVFA (plus valerate), all 3 branched-chain AA (BCAA), or half of each BCVFA and BCAA mix with either alfalfa or grass hays (50%) and ground corn grain (50%). A portion of the BCAA and BCVFA doses were enriched with ¹³C, and valerate (also enriched with ¹³C) was added with BCVFA. Although BCAA yielded a similar production of BCVFA compared with dosing BCVFA, equimolar substitution of BCVFA for BCAA decreased the percentage of N in bacterial pellets when alfalfa hay was fed but increased N when grass hay was fed. Substituting BCVFA for BCAA increased total fatty acid (FA) concentration with alfalfa hay. Dosing of BCAA or BCVFA did not affect total branched-chain FA, iso-FA, or anteiso-FA percentages in bacterial total FA, whereas numerous individual FA isomers and their ¹³C enrichments were affected by these treatments. Increasing recovery of the ¹³C dose from respective labeled BCVFA primers indicated facilitated BCVFA uptake and incorporation into FA compared with BCAA, whereas increased recovery of ¹³C from labeled BCAA in the bacteria pellet but not in the FA fraction suggested direct assimilation into bacterial protein. The BCVFA and valerate were dosed in varying combinations that either summed to 4 mM (experiment 2) or had only 1 mM no matter what combination (experiment 3). In general, grass hay was more responsive to stimulation in NDF digestibility by BCVFA than was alfalfa hay, which was attributed to the higher degradable protein in the latter. The net production of the BCVFA (after subtracting dose) was affected by source and combination of BCVFA. Isovalerate dosing tended to increase its own net production; in contrast, isobutyrate seemed to be used more when it was added alone, but 2-methylbutyrate seemed to be preferred over isobutyrate when 2-methylbutyrate was added. Results supported potential interactions, including potential feedback in production from feed BCAA or increased concentration-dependent competition for dosed BCVFA into cellular products. Under our conditions, the BCVFA appear to be more readily available than BCAA, probably because of regulated BCAA transport and metabolism. Valerate consistently provided no benefit. Using nonparametric ranking, all 3 BCVFA or either isovalerate or isobutyrate (both yielding iso-FA) should be combined with 2-methylbutyrate (yielding anteiso-FA) as a potential opportunity to improve NDF digestibility when rumen-degraded BCAA are limited in diets to decrease environmental impact from N in waste.     

Effects of antibiotics and oil on microbial profiles and fermentation in mixed cultures of ruminal microorganisms

Ionophores and supplemental fat are fed to lactating cows to improve feed efficiency. Their effect on rumen fermentation is similar, but less is known about their impact on rumen microbes. The objective of this study was to determine the effects of monensin (M), bacitracin (B), and soybean oil (O) on microbial populations. Mixed cultures of rumen microbes were incubated in 5 dual-flow continuous fermentors and fed 13.8 g of alfalfa hay pellets daily (DM basis) for 16 d. All fermentors were allowed to stabilize for 4 d. From d 5 to 10, two fermentors received O (5% of diet DM), one fermentor received M (22 mg/kg), and one received B (22 mg/kg). From d 11 to 16, the 2 fermentors receiving O also received either M (OM) or B (OB) and O was included in the fermentors receiving M (MO) and B (BO). One fermentor served as the control and received 100% alfalfa pellets throughout the experiment. Each run was replicated 3 times. Samples were taken at 2 h after the morning feeding on d 4, 10, and 16 and were analyzed for bacterial populations using terminal restriction fragment length polymorphism. Volatile fatty acid concentration, methane production, and pH in the control cultures were not affected by time and remained similar during the entire experiment. The M and O treatments reduced molar concentration of acetate, increased concentration of propionate, and decreased methane production. Bacitracin did not alter acetate or propionate concentration, but reduced methane production. All 3 treatments (M, B, and O) altered the fragment patterns of microbial profiles. In contrast, treatments MO, OM, BO, and OB had little effect on culture fermentation despite differences in the patterns of microbial fragments. The terminal restriction fragment length polymorphism data suggest that microbial adaptation to the in vitro system in the control fermentor occurred within 4 d.     

在模型化基础上对青霉素补料分批发酵过程中经济效益的预测

在研究发酵动力学、生物过程反应计量学、代谢流分布和代谢流控制的基础上 ,结合专家知识、实验及生产数据 ,对生产规模的青霉素反复补料分批发酵 (即半连续发酵 )的全过程进行了数学模拟 ,建立了一套包含 2 5个过程变量和一系列经济学变量的改良机理模型 .根据这一模型 ,预测了一些工艺参数和经济学参数的改变对发酵过程经济效益的影响 ,发现在保持最大生物质浓度、稀释速率 ,及其它工艺条件不变的情况下 ,中间放料间隔时间、初始发酵液体积以及葡萄糖和电力的价格对经济效益产生较大的影响 .模拟运算结果表明 ,葡萄糖和电力的价格降低 5 % ,全年利润可分别提高 6 .35 %和 3.75 % ;中间放料间隔时间由 2 4h缩短为 12h和 1h(接近于连续发酵 ) ,全年利润可分别提高 7.2 2 %和 14 .11% ;初始发酵液装罐体积分数由 75 %提高到 85 % ,全年发酵利润可提高 5 .4 8% .     

Effect of Saccharomyces cerevisiae fermentation product on ruminal fermentation and nutrient utilization in dairy cows

The goal of this experiment was to investigate the effect of yeast culture (Saccharomyces cerevisiae) on rumen fermentation, nutrient utilization, and ammonia and methane emission from manure in dairy cows. Eight ruminally cannulated Holstein cows were allocated to 2 dietary treatments in a crossover design. Treatments were control (no yeast culture) and XP (yeast culture, fed at 56 g/head per day; XP, Diamond V Mills Inc., Cedar Rapids, IA). Dry matter intake, milk yield, milk composition, and body weight were similar between treatments. Milk urea nitrogen concentration was also not affected by treatment. Rumen pH was similar between the control and XP treatments, but rumen ammonia concentration tended to be lower with XP than with the control. Treatment had no effect on concentrations of total or individual volatile fatty acids, protozoal counts, polysaccharide-degrading activities (except amylase activity that tended to be increased by XP), or methane production in the rumen. Urinary N losses did not differ significantly between treatments, but allantoin and total purine derivative excretions and the estimated microbial N outflow from the rumen tended to be increased by XP compared with the control treatment. Total-tract apparent digestibility of dietary nutrients was not affected by XP. Milk fatty acid composition was also not altered by XP supplementation. Cumulative (253 h) ammonia and methane emissions from manure, measured in a steady-state gas emission system, were slightly decreased by XP. Overall, the yeast culture tested had little effect on ruminal fermentation, digestibility, or N losses, but tended to reduce rumen ammonia concentration and increase microbial protein synthesis in the rumen, and decreased ammonia and methane emissions from manure.     

Cellulose acetate,a new candidate feed supplement for ruminant animals: In vitro evaluations

Cellulose acetate (CA), a derivative of cellulose in which some hydroxyl groups are substituted with acetyl groups, was evaluated as a new cellulosic feed source for ruminants. In the present work, a series of in vitro studies was carried out to determine how CA supplementation affects rumen fermentation and microbiota. Batch culture studies were conducted to select the type of CA suitable for feed use and to define the optimal supplementation level. Rumen fluid from 2 Holstein cows was mixed with McDougall's buffer in test tubes into which grass hay and concentrate containing a fiber source [cellulose (control), water-soluble CA (WSCA), or insoluble CA] had been placed. Each fiber source was supplemented at 10% of total substrate. Tubes were incubated for 24 h to determine fermentation and microbial parameters. Then, the dose response of these parameters to different supplementation levels of WSCA (0, 7.5, 15, 22.5, and 30%) was tested in the same manner. We also operated a continuous culture system with WSCA supplementation and evaluated the effects on digestibility, fermentation, and microbial parameters. The supplementation level of WSCA was set at 15% of total feed. In batch culture studies, WSCA, but not insoluble CA, yielded dose-dependent increases in ruminal acetate levels. In the continuous culture system study, WSCA yielded increases in ruminal acetate levels and in the abundance of bacteria of the genus Prevotella, including Prevotella ruminicola. Dry matter digestibility and total gas production were not affected. These results suggest that WSCA supplementation at 15% of total feed yielded increased acetate levels without negatively affecting feed digestion; these effects may reflect activation of Prevotella species. As ruminal acetate is involved in milk fat synthesis, WSCA can be considered as a candidate feed additive suitable for dairy cattle.     

Effects of including corn distillers dried grains with solubles in dairy calf feeds

A series of 5 trials was conducted to determine the effect of distillers dried grains with solubles (DG) in calf diets. Trial 1 compared 0 or 49% DG in 18% crude protein (CP) starters (as-fed basis) fed to calves initially 2 to 3 d old for 56 d. Digestibility was estimated during d 52 to 56 using chromic oxide. Trial 2 compared 0 or 39% DG in 16% CP growers fed to calves from 8 to 12 wk of age from 28 d. Trial 3 compared 0, 10, or 20% DG in 18% CP starters fed to calves initially 2 to 3 d old for 56 d. Trial 4 compared 0 or 20% DG in 16% CP growers fed to calves from 8 to 12 wk of age from 28 d. As DG increased in all diets, acid detergent fiber, neutral detergent fiber, and fat increased and calculated metabolizable energy was similar but not equalized. In trials 1 and 3, calves (n = 48/trial) housed in individual pens were fed 26% CP, 17% fat milk replacer powder and weaned at 28 d. Trials 2 and 4 used calves (n = 48/trial) housed in group pens (6 calves/pen) that had been weaned for 28 d before the trials’ start. Trial 5 (n = 18 calves) had the same starter treatments as trial 3 fed in combination with high or low milk replacer intake, with calves killed at 35 d to determine effects of DG and milk replacer intake on rumen development. In trial 1, average daily gain (ADG) was 6% greater and dry matter digestibility was 10% greater for calves fed 0% versus 49% DG. In trial 2, ADG (9%), feed efficiency (10%), and hip width change (19%) were greater for calves fed 0% versus 39% DG. Performance measures did not differ among starter treatments in Trials 3 and 5. In trial 4, ADG (4%), feed efficiency (5%), and hip width change (19%) were greater for calves fed 0% versus 20% DG. In trial 5, rumen development was not affected by DG inclusion, but was greater for calves fed milk replacer at 630 versus 940 g/d, which had greater starter intake. Overall, we conclude that high levels of distillers in calf starters and growers decrease growth of calves; however, starters with ≤20% DG allow for normal growth rates and rumen development.