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1.
Total viable rumen bacteria counts through the use of colony-unit forming assays lack accuracy because they only include culturable bacteria capable of initiating cell division. Thus, bacterial counts can be underestimated. The use of fluorescent characteristics of cell membranes allows flow cytometry to enumerate and distinguish dead from live bacteria cells. The objective of this experiment was to investigate the viable and total ruminal bacteria counts when 3 levels of forage:concentrate in diets were fed at restricted levels with the addition of Saccharomyces cerevisiae (YC). Three cannulated post-pubertal Holstein heifers (age 18 ± 1.0 months) were fed corn silage (CS)-based diets in a 3-period (35 d) Latin square design. Heifers were fed the diets for 21 d with no yeast addition, followed by 14 d where yeast culture (YC) was added (1 g/kg as-fed basis); (Yea-Sacc1026, Alltech, Inc., Nicholasville, KY). A low concentrate (LC) TMR (80% CS, 20% concentrate; 12.4% CP, 35% NDF), a medium concentrate (MC) TMR (60% CS, 40% concentrate; 12.3% CP. 28% NDF), and a high concentrate (HC) TMR (40% CS, 60% concentrate; 12.6% CP, 25% NDF), were fed once per day. Rumen fluid was sampled − 2, 0, 2, 4, 6, 8, 10, 12 h after feeding. Samples were immediately stained with fluorescent dyes using the BacLight kit (Molecular Probes Inc., Eugene, OR) and analyzed with a Coulter XL-MCL single laser flow cytometer. Mean rumen viable bacteria counts linearly increased among treatments (4.96, 4.78, 6.73 × 1011 ± 0.53 × 1011 cells/ml; P = 0.02) for LC, MC and HC respectively, and YC addition increased number of viable bacteria cells (P < 0.01). Total and viable bacteria counts decreased for the first 2 h after feeding then increased 4 h post-feeding. Dietary concentrate level and YC can alter rumen bacteria counts as measured by this method.  相似文献   

2.
This experiment was conducted to evaluate the effects of dietary treatments on microbial loads and pH of gastrointestinal tract contents in meat goats, as well as the concentration of volatile fatty acid (VFA) in the rumen. Crossbred (Boer x Spanish) goats (n = 36; BW = 17.7 kg) were assigned randomly to one of three experimental diets (n = 12/diet or 3 pens/treatment) for 90 days:alfalfa (Medicago sativa) hay alone (AH-diet); 18% CP concentrate alone (C-diet); or, a combined diet (AHC-diet), consisting of the AH-diet for the first 45 days, followed by 45 days of the C-diet. After evisceration, pH values of rumen liquor and colon digesta were immediately measured from each animal, as well as aseptically collected rumen liquor and rectal samples to determine the microbial loads. Collected rumen liquor was also prepared for volatile fatty acid (VFA) contents. Feeding meat goats with alfalfa hay alone had higher (P < 0.05) rumen (7.17) and colon (7.10) pH compared with those fed either the concentrate alone or combined-diet. Although the acetate content was high in the AH-fed group (66.3 mM) compared to the AHC-diet group (34.6 mM), no significant differences were found in the total VFA contents in rumen liquor among the goats fed three different dietary regimens. Total plate counts were not significantly different among goats fed the experimental diets in the rumen or rectal samples. Escherichia coli counts in the rectal samples were lower (P < 0.05) in the AH-diet group (6.43 log10 CFU/g) compared with the C-diet (8.21 log10 CFU/g) or AHC-diet (8.40 log10 CFU/g) groups. However, no significant differences were found in the E. coli counts of rumen samples from goats fed the experimental diets. The mean (± SEM) rumen E. coli counts were 1.38, 1.65, and 2.51 ± 0.560 log10 CFU/g in the AH-, C-, and AHC-diet groups, respectively. The results indicate that feeding hay alone may decrease the fecal shedding of E. coli in meat goats with increasing the rumen and colon pH.  相似文献   

3.
This study was conducted to determine the effects of mixtures of liquid brewer’s yeast (LBY) and cassava pulp (CVP) with rice straw (RS) on feed intake, digestibility, rumen fermentation, and growth of dairy heifers. Sixteen Holstein crossbred heifers (13.8?±?1.6 months old, 210?±?23 kg body weight (BW)) were randomly allocated to four feeding treatments with four replications, which were 0:0:100 (RS), 0:70:30 (0%LBY), 20:50:30 (20%LBY), and 50:20:30 (50%LBY), respectively, for LBY/CVP/RS on a fresh matter basis. The heifers were offered conventional concentrate at 1.5% initial body weight daily and fed the treatment diets ad libitum. Average daily gain and feed intake were not significantly different among the treatments. The heifers fed 50%LBY had the highest crude protein (CP) intake and DM, OM, and CP digestibility (P?<?0.05). The ruminal pH did not differ significantly among treatments, while NH3-N was the highest (P?<?0.05) in 50%LBY. Total volatile fatty acid (VFA) concentrations and the molar proportion of each VFA were not significantly different among the treatments. Blood urea nitrogen concentrations of 50%LBY were the highest among the treatments (P?<?0.05). The results indicated that 50%LBY improved CP digestibility.  相似文献   

4.
The objective of this study was using a wide range of dietary concentrate levels to investigate the major effects of limit‐feeding on heifers. Twenty‐four Holstein heifers were blocked into six groups and fed with one of four diets containing different levels of concentrate (20%, 40%, 60% and 80% on a dry matter (DM) basis) but with same intakes of metabolizable energy for 28 days. Increasing levels of dietary concentrate caused decreased (P ≤ 0.02) intakes of dry matter (DMI) and neutral detergent fiber and total rumination time, but increased (P < 0.01) nonfiberous carbohydrates intake, ruminal concentrations of NH3‐N, propionate and butyrate, and digestibility of DM and crude protein. Dietary concentrate levels had no significant effect on most plasma concentrations and body measurements. The corrected average daily gain (CADG) and feed efficency (ADG/DMI, CFE) were linearly increased (P < 0.01) with increasing dietary concentrate levels when gut fill impact was removed. In conclusion, heifers limit‐fed high concentrate diets increased most ruminal fermentation parameters, CADG and CFE with similar body growth and blood metabolites as heifers fed low concentrate diets, and had the potential to be used as an effective feeding strategy in dairy heifers.  相似文献   

5.
本试验旨在探讨不同精粗比日粮对奶山羊瘤胃液pH值、VFA以及血液中VFA含量的影响。选择8只安装永久性瘤胃瘘管的奶山羊作为试验动物,采用完全随机分组试验设计随机分为2组,分别饲喂精粗比为6∶4和4∶6的日粮,预饲期15 d,采样期3 d。结果表明,高精料组(HC组)瘤胃液pH值显著低于低精料组(HR组)(P<0.05);在采食后3 h,HC组与HR组瘤胃液pH值均下降至最低值,分别为5.71和6.08。除了乙酸含量外,HC组瘤胃液丙酸、异丁酸、丁酸、异戊酸、戊酸以及总挥发性脂肪酸(TVFA)含量分别比HR组提高4.99%、5.58%、21.81%、17.95%、18.27%、1.66%。HC组血浆中各种VFA的含量均高于HR组,其中丙酸、丁酸含量两组间差异达到显著水平(P<0.05)。HC组瘤胃液以及血浆中乙酸与丙酸比值均低于HR组,但两组间差异均不显著(P>0.05)。HC组瘤胃液乙酸、丙酸、TVFA浓度在采食后2 h达到最大值,HR组在采食后3 h达到最大值,两组日粮血浆中VFA浓度均在采食后2 h达到最大值,然后逐渐恢复到采食前水平。结论:高精料日粮导致瘤胃液pH值显著降低,瘤胃液和血浆中VFA含量增加;瘤胃液VFA生成速率HC组高于HR组。  相似文献   

6.
The effects of anti-lipopolysaccharide (LPS) antibody on rumen fermentation and LPS activity were investigated during subacute ruminal acidosis (SARA) challenge. Eleven Holstein cattle (164 ± 14 kg) were used in a 3 × 3 Latin square design. Cattle were fed a roughage diet on days −11 to −1 (pre-challenge) and day 2 (post-challenge), and a high-grain diet on days 0 and 1 (SARA challenge). For 14 days, 0-, 2-, or 4-g of anti-LPS antibody was administered once daily through a rumen fistula. Ruminal pH was measured continuously, and rumen fluid and blood samples were collected on days −1, 0, 1, and 2. Significantly lower ruminal LPS activity on day 1 was observed in the 2- and 4-g groups than those in the 0-g group. In addition, significantly higher 1-hr mean ruminal pH on SARA challenge period (days 0 and 1) was identified in the 4-g group than in the 0-g group. However, rumen fermentation measurements (total volatile fatty acid [VFA], VFA components, NH3-N and lactic acid) and peripheral blood metabolites (glucose, free fatty acid, beta-hydroxybutyrate, total cholesterol, blood urea nitrogen, aspartate aminotransferase and gamma-glutamyl transferase) were not different among the groups during the experimental periods. Therefore, anti-LPS antibody administration mitigates LPS release and pH depression without the depression of rumen fermentation and peripheral blood metabolites during SARA challenge in Holstein cattle.  相似文献   

7.
酵母培养物对内蒙古白绒山羊瘤胃发酵的影响   总被引：3，自引：1，他引：3  
选择12只年龄相同的安装永久性瘤胃瘘管的内蒙古白绒山羊半同胞羯羊,按体重配对原则分为4组,其中A1、A3处理组饲喂精粗比为3∶7的基础日粮,B1、B2处理组饲喂精粗比为2∶8的基础日粮。采用自身对照试验方法,对照期饲喂基础日粮,试验期在基础日粮中分别添加不同水平的酵母培养物(YC)。各处理YC添加量A1为2.0%;A3为3.0%;B1为2.0%;B2为2.5%。结果表明:添加YC极显著(P<0.01)降低A3和B1处理瘤胃NH3-N浓度,极显著(P<0.01)提高A1处理的瘤胃NH3-N浓度。添加YC能显著(P<0.05)提高绒山羊瘤胃乙酸、丙酸和丁酸的浓度,总VFA浓度得到极显著(P<0.01)提高;对乙酸/丙酸比没有显著影响。显著提高B1和B2处理菌体蛋白含量。  相似文献   

8.
The experiment was conducted to evaluate the effects of dietary supplementation with a mixture of essential oils (MEO), yeast culture (YC) and malate on performance, nutrient digestion, rumen fermentation and blood metabolites of lambs fed high‐concentrate growing diets. For this purpose, twenty Baluchi lambs (17.3 ± 0.5 kg body weight and 3 months old) were randomly assigned to four dietary treatments in a completely randomized design with five lambs per treatment. The treatment groups were as follows: (i) control: basal diet without any additive, (ii) basal diet plus 400 mg/day MEO (thymol, carvacrol, eugenol, limonene and cinnamaldehyde), (iii) basal diet with 4 g/day YC and (iv) basal diet plus 4 g/day malate. No differences between the dietary treatments were observed in dry matter intake, average daily gain or feed conversion ratio (p > 0.05). Compared with control and malate treatment, lambs fed MEO and YC had an improved crude protein digestibility (p < 0.05). Yeast culture significantly increased (p > 0.05) cell wall digestibility compared to the other treatments. No differences were observed between treatments with respect to nitrogen balance or ruminal pH and ammonia concentrations (p > 0.05). No differences were observed between treatments with respect to ruminal total volatile fatty acid concentration and molar proportions of acetate, butyrate and valerate. Molar proportion of propionate was higher (p < 0.05) for YC and malate compared to control and MEO. Plasma glucose concentration was higher (p < 0.05) in lambs fed YC and malate than in lambs fed the control or the MEO diet. Blood concentration of triglycerides significantly decreased when feeding the MEO and YC diets (p < 0.05). It was concluded that YC may be more useful as a feed additive for manipulation of rumen fermentation in lambs fed with high‐concentrate diets than MEO and malate, because YC enhanced crude protein and cell wall digestibility, ruminal molar proportion of propionate and plasma glucose concentration.  相似文献   

9.
Two experiments were conducted to investigate the effects of the addition of Zn to high quality diets on ruminal fermentation and hydrolysis of urea in vitro and in vivo. In Experiment 1, single effluent continuous culture fermentors were maintained on alfalfa hay-based diets with or without added Zn (400 ppm in total diet) for 4 d. On day 5, 2 g urea were added to the fermentors, and determination of concentrations of VFA and NH4+ in the fluid followed for 8 h. The addition of Zn did not affect concentrations of total VFA or NH4+ in the fluid from the fermentors. In Experiment 2, four non-lactating, Holstein cows previously fitted with ruminal cannulas were used in a switchback-designed experiment. Cows were fed the same diets used in the in vitro experiment at restricted (5.71 kg DM) intakes. The addition of Zn to these diets had no impact on ruminal NH4+ concentrations or concentrations of total VFA in ruminal fluid. However, the addition of Zn to diets did change proportions of individual VFA in ruminal fluid. The proportion of propi-onate tended to increase, and the proportion of butyrate tended to decrease, when Zn was added to the diets. These data indicate that supplemental Zn was ineffective in preventing urea hydrolysis when fed with high quality diets but was effective in altering the fermentation pattern.  相似文献   

10.
The effects of doses CTL (0 mg), 30, 300 and 3000 mg/L of extracts from Stryphnodendron adstringens (Mart.) Coville (SA), Lafoensia pacari A. St.-Hil (LP), Copaifera spp. (CO) and Pterodon emarginatus Vogel (PE) on ruminal fermentation were investigated in eight experiments conducted in randomized complete block designs. The in vitro system contained four fermentation vessels. Each treatment was allocated in one vessel in each run. Incubation was run four and five times with diets 50:50 and 10:90 (roughage to concentrate ratio) respectively. Incubation vessel was the experimental unit, and each incubation run was a block. All plant extracts negatively affected DM degradation at 3000 mg/L. In diet 50:50, SA-3000 increased the molar proportion of propionate (p < 0.05), yet it decreased the concentration of fermentation products (p < 0.05); LP-300 reduced ruminal ammonia nitrogen (NH3-N; 98 vs. 120 mg/dl for LP-300 and average of CTL and LP-30, respectively) and isobutyrate (p < 0.05); CO-300 reduced (p < 0.05) NH3-N (98 vs. 123 mg/dl for CO-300 and average of CTL and CO-30, respectively); and P. emarginatus had no positive effects on rumen fermentation (p > 0.05). In diet 10:90, SA-300 reduced (p < 0.001) NH3-N and total volatile fatty acids (VFA); LP-30 increased (p < 0.05) total VFA (85 vs. 63 mM for LP-30 and CTL, respectively), molar proportions of acetate and propionate, and had lower C2:C3 than CTL (3.6 vs. 4.3, respectively); CO-300 decreased acetate and increased propionate, reducing C2:C3 (p < 0.001; 2.8 vs. 3.6 for CO-300 and average of other doses, respectively); PE-30 and PE-300 reduced NH3-N by 14% and increased total VFA by 29% compared with CTL (p < 0.05). Further in vivo investigations may consider L. pacari (LP-30), Copaifera spp. (CO-300) oleoresin and P. emarginatus oleoresin (PE-30 and PE-300) in diets with high inclusion of concentrate.  相似文献   

11.
Six Japanese Black (Wagyu) steers (average initial weight 467 ± 45 kg) fitted with a ruminal cannula were used in a split‐plot design experiment comprising a 3 × 3 Latin square design (whole‐plot) and a randomized block design (subplot). The whole‐plot treatments were three different feeding levels of urea‐treated potato pulp (PP) silage‐based concentrate: 1.00%, 1.75% and 2.50% of body weight (BW) (on a dry matter (DM) basis). The subplot treatments consisted of the concentrate formulated to contain either soybean meal (SBM) as a rapidly rumen‐degraded protein source or corn gluten meal (CGM) as a slowly degraded protein source. Dry matter intake tended to be lower (P = 0.071) for CGM (8.9 kg/day) than for SBM (9.4 kg/day). Protein sources had no significant effect on digestibility and in situ degradation. Ruminal ammonia nitrogen (NH3‐N) was lower (P = 0.033) for CGM (7.5 mg/dL) than for SBM (9.5 mg/dL). Protein sources did not affect ruminal pH and the total volatile fatty acids (VFA) concentrations. The molar proportions of ruminal acetate and valerate were higher (P = 0.032) for CGM than for SBM. The maximum daily intake of the PP silage‐based concentrate expressed as a percentage of BW was approximately 1.4% of BW. Dry matter intake was higher (P = 0.046) for steers fed at 1.0% of BW of the PP silage‐based concentrate than for steers fed at 1.75% or 2.5% of BW of the concentrate. The feeding levels of the PP silage‐based concentrate had no effect on DM and nutrients digestibility, except for crude protein (CP) digestibility. CP digestibility tended to be lower (P = 0.071) for steers fed at 1.75% of BW of the PP silage‐based concentrate than for steers fed at 1.0% or 2.5% of BW of the concentrate. The feeding levels of the PP silage‐based concentrate also did not affect the in situ degradation parameter of hay and PP silage. The feeding levels of the PP silage‐based concentrate did not affect ruminal pH, NH3‐N and total VFA concentrations. The molar proportion of acetate was highest for steers fed at 1.0% of BW of the concentrate. In conclusion, in the urea‐treated PP silage‐based concentrate, CGM seems to be more effective than SBM for stabilizing the ruminal NH3‐N concentration and to be advantageous for fiber digestion in the rumen. The feeding levels of the PP silage‐based concentrate did not change the amount of VFA production in the rumen and the DM digestibility.  相似文献   

12.
The effects of including yeast culture (YC; Saccharomyces cerevisae plus growth medium; 5 x 10(9) organisms/g) in diets for ruminants was examined in two experiments. In Exp. 1, 32 multiparous Friesian dairy cows were fed between wk 7 to 12 of lactation one of four completely mixed diets based on either hay or straw plus rolled barley (mixed to give concentrate:forage ratios of either 50:50 or 60:40, respectively) with or without 10 g YC/d in a 2(3) factorial design. Supplementation with YC increased DM intake of the cows by a mean of 1.2 kg/d (P less than or equal to .062) and increased milk yield by 1.4 liters/d (corrected to 4% butterfat; P less than or equal to .05). There was an interaction (P less than .05) between diet composition and YC addition; effects of YC were greatest in diets containing 60:40 (concentrate:forage) ratio. In Exp. 2, three steers were fed a diet of 50% hay and 50% rolled barley (DM basis). Hay was available for the major part of the day but barley was fed in two meals/d. Addition of YC to the diet increased (P less than .05) ruminal pH for 4 h after the barley meal. This elevation in pH probably was due to a reduction (P less than or equal to .01) in the concentration of L-lactate in the ruminal liquor of steers given YC (1.43 vs 3.55 mM; P less than or equal to .01). Peak ruminal L-lactate concentration (7.75 mM) in the controls coincided with time of minimum pH values (2 h after the meal of barley); this peak was absent in steers given YC. YC had no effect on the concentration of VFA in ruminal liquor, but the ratio of acetate to propionate was reduced (P less than or equal to .01) from 3.3:1 to 2.8:1 in steers given YC. The extent of DM degradation of hay incubated in the rumen of steers fed the hay and rolled barley diet was increased (P less than .05) in the presence of YC at 12 h of incubation, but degradation was similar in all treatment groups after 24 h of incubation. Presence of yeast culture in the rumen had effects on ruminal stoichiometry. An increased rate of forage degradation may have increased forage intake and productivity of these dairy cows.  相似文献   

13.
The aim of the current study was to investigate the associative effects of a cornstalk-based diet supplemented with alfalfa (Medicago sativa) hay on intake, digestibility, nitrogen (N) metabolisation, rumen environment and hematological parameters in Xiaoweihan sheep. We also investigated the optimal range of alfalfa hay to achieve positive associative effects and avoid negative effects. Xiaoweihan sheep (n = 5; fitted with rumen T-cannula) were fed five cornstalk-based diets in a 5 × 5 Latin square design. Diets contained 0, 50, 150, 300, 450 g alfalfa, and were supplemented with 100 g concentrate, respectively. Our results suggested that supplementation of 300 g alfalfa hay reduced (P < 0.05) cornstalk intake, but significantly increased dry matter (DM) intake (P < 0.05). Additionally, DM digestibility of 150 g alfalfa hay supplementation was slightly higher than that noted in other diets. Metabolism studies showed 50–150 g alfalfa hay supplementation had a positive associative effect (P < 0.05) on N utilization, with the greatest benefit noted with 150 g per day (P < 0.05) compared to unsupplemented diets. Alfalfa supplementation (50–450 g per day) resulted in an elevated trend of ammonia nitrogen (NH3–N) with 50 or 150 g of alfalfa hay more likely to promote sheep rumen environment, with a noticeable increase (P < 0.05) in serum urea nitrogen (UREAN) concentrations observed with 300 g alfalfa hay per day. Our data suggested that the optimal range to achieve beneficial effects and avoid negative effects was 150–300 g per day for cornstalk-based diets for sheep.  相似文献   

14.
Three, multiparous Holstein crossbred dairy cows with initial body weight of 385 ± 19 kg were randomly allocated to 3 treatments of rice straw (T1 = untreated rice straw; T2 = 5.5% urea-treated rice straw (5 g urea in 100 ml water to 100 g air-dry (91% DM) straw); T3 = 2.2% urea + 2.2% calcium hydroxide treated rice straw (2.0 g urea and 2.0 g Ca(OH)2 in 100 ml to 100 g air-dry (91% DM) straw) according to a 3 × 3 Latin square design. Each period lasted for 21 days in which feed, feces and rumen fluid were collected during the last 7 days for chemical analyses. The findings revealed significant improvements in dry matter intake and digestibility by using 5.5% urea-treated rice straw and 2.2% urea + 2.2% calcium hydroxide treated rice straw. Ruminal pH and NH3-N were found higher (P < 0.05) as compared with urea-treated rice straw fed group, while blood urea nitrogen and milk urea nitrogen were in normal ranges. Volatile fatty acid concentrations especially those of acetic acid were decreased (P < 0.05) and those of propionic acid were increased (P < 0.05), thus acetic acid:propionic acid was subsequently lowered (P < 0.05) in cows fed with 5.5% urea-treated rice straw and 2.2% urea + 2.2% calcium hydroxide treated rice straw, respectively. Moreover, ruminal viable and cellulolytic bacterial counts were enhanced by urea and calcium hydroxide treatments. Milk protein and fat concentrations were additionally increased by respective treatments while 3.5% fat-corrected milk was highest; ranking from 2.2% urea + 2.2% calcium hydroxide treated rice straw, 5.5% urea-treated rice straw and urea-treated rice straw fed groups. Based on this study, implications could be made that using 2.2% urea + 2.2% calcium hydroxide treated rice straw for straw treatment could be an alternative treatment to 5.5% urea treatment with regards to its effectiveness and treatment cost for lactating dairy cows.  相似文献   

15.
An experiment was conducted with eight ruminally-cannulated cows using a crossover design with 2 periods to determine the effects of yeast supplementation on rumen fermentation. Holstein dairy cows in late lactation were either supplemented with 0.5 g/hd/d of Saccharomyces cerevisiae, an active dry yeast (CNCM-1077, Levucell SC20 (r) SC, Lallemand Animal Nutrition) or not supplemented (control). A basal diet consisting of 60% forage and 40% concentrate (DM basis) was fed once daily to both groups of cows throughout the entire experiment. Ruminal pH was measured continuously every 22 min using a pH probe that was placed in the ventral rumen sac for 6 consecutive days. Volatile fatty acid and ammonia N concentrations in the rumen were measured on days 5 or 6 of the 12-d period for each cow and DM intake was monitored throughout the experiment. Data were analyzed using a mixed-effects model with repeated measures. There were no differences in dry matter intake between treatments. Mean ruminal pH was greater (P < 0.05) when yeast was supplemented (6.53 ± 0.07) compared with the control (6.32 ± 0.07). Average maximum and minimum ruminal pH were also greater (P < 0.05) when yeast was supplemented (7.01 ± 0.09 and 5.97 ± 0.08, respectively) compared with the control (6.80 ± 0.09 and 5.69 ± 0.09, respectively). Time spent under the subacute acidosis threshold, pH less than 5.6, was lower (P < 0.05) with yeast supplementation compared with control cows. No difference was observed for ruminal ammonia N concentrations (mean = 14.0 ± 1.2 mg/dL) between treatments. Total VFA concentration (mM) in the rumen tended to be lower (P = 0.10) in the yeast-supplemented cows (107.3 ± 6.35) than in the control cows (122.4 ± 6.35), which could be related to the greater pH observed with yeast supplementation. Supplementing dairy cows with active dry yeast in the current experiment increased the mean, minimum and maximum ruminal pH; decreased time spent in subacute rumen acidosis, and tended to decrease total VFA concentration in the rumen compared with control cows.  相似文献   

16.
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17.
试验采用3×3拉丁方设计,3头安装永久性大口径瘤胃瘘管的青年母牛饲喂3种不同精饲料的日粮,3种精饲料分别为豆粕+玉米(日粮1),猪血粉+玉米(日粮2)和豆粕+小麦(日粮3)。精料日喂量按活牛体重的1%喂给,干玉米秸等量组成的日粮配给。试验为3个试验周期,每一周期为37d,其中适应期26d,在早晨采食后2、4、8、16和24h,分别5次实施瘤胃掏空,全量测定瘤胃物存留量。结果表明:日粮1在采食后2～8h瘤胃干物质、液体和NDF的存留量最低,与其他两种日粮相比差异显著(P<0.05);日粮1和日粮3瘤胃液氨氮存留量在采食后2～8h始终高于日粮2(P<0.05),但日粮3在采食4h后瘤胃液氨氮开始下降,而日粮1至采食后16h开始下降,日粮1瘤胃液氨氮数量采食后2～8h处于高峰状态,说明瘤胃微生物在瘤胃环境长时间一直保持稳定的降解能力;日粮1和日粮3在采食2～4h后处于较高的总挥发性脂肪酸(VFA)瘤胃存留量,日粮1在采食后8～16h瘤胃存留量降低,与日粮2和日粮3相比差异显著(P<0.05),日粮1对瘤胃VFA的快速移除,意味着瘤胃液的快速流出以及可能解释瘤胃固体物的快速移除。因此,日粮1和日粮3在牛瘤胃洗涤纤维降解和瘤胃液产物代谢模式发挥不同作用。  相似文献   

18.
The objectives of this study were to investigate the effect of different dietary ratios of forage and concentrate (F:C) on ruminal odd‐ and branched‐chain fatty acids (OBCFAs) contents and to evaluate the relationships between OBCFA and ruminal fermentation parameters as well as bacterial populations tested by real‐time PCR technique. The experimental design was a 3 × 3 Latin square. Three rumen‐fistulated dry Holstein cows were fed three rations with different dietary F:C ratios (F:C; 30:70, 50:50 and 70:30). The rumen samples were collected every two hours (0600, 0800, 1000, 1200, 1400, 1600, 1800, 2000, 2200, 2400, 0200 and 0400 h) over three consecutive days in each sampling period. The results showed that rumen OBCFA profiles are significantly (p < 0.05) affected by the dietary F:C ratios. The concentrations of C11:0, C13:0, iso‐C15:0, iso‐C16:0, iso‐C17:0 and C17:0 were higher in the cows fed dietary F:C ratio of 70:30 than those fed with other two rations. However, the concentrations of anteiso‐C15:0, C15:0 and total OBCFA were on the lowest level in the high forage diet. Correlation and regression analysis showed that ruminal OBCFAs had strong relationships with ruminal fermentation parameters and bacterial populations. In particular, the iso‐fatty acids had potential power to predict butyrate and isoacids metabolized in the rumen, whereas the fatty acids with 17 carbon atoms correlated with ruminal NH3‐N content. The OBCFA contents have different relationships with fibrolytic and starch bacteria in the rumen. C17:0 and its isomers might be used to predict populations of fibrolytic bacteria.  相似文献   

19.
The aim of the study was to investigate the effect of feeding different diets on fermentation, enzyme activities and microbial population in the rumen fluid of mithun (Bos frontalis). In a randomized block design, 20 male mithun (6–8 months of age, 152 ± 12.6 kg body weight) were randomly divided into four experimental groups (n = 5/group) and fed experimental diets ad libitum for 180 days. The diet R1 contained tree foliages (TF), R2 comprised of 50% concentrate mixture (CM) and 50% TF, R3 contained 50% CM and 50% rice straw, and R4 contained 50% CM, 25% TF and 25% rice straw. Rumen liquor was collected at 0 and 180 days of the experiment for estimation of different ruminal parameters and a digestion trial was conducted at the end of the experiment. Rumen fluid was analysed for pH, ammonia nitrogen (NH3‐N), total‐N, ruminal enzymes, short chain fatty acid (SCFA) and microbial profile. The relative quantification of ruminal microbes was carried out with real‐time PCR using bacteria as the house keeping gene. The dry matter intake, nutrients digestibility, body weight gain, NH3‐N, total‐N, carboxymethyl cellulase, avicelase, xylanase, amylase, protease and molar proportion of butyrate were (p < 0.05) higher in mithun fed R2, R3 and R4 compared to those fed R1 diet. In contrast, increased (p < 0.05) ruminal pH, molar proportion of acetate and, acetate to propionate ratio was recorded in mithun fed only TF than those fed concentrate supplemented diets. Similarly, an increase (p < 0.05) in the population of Fibrobacter succinogenes, Ruminococcus flavefaciens and total bacteria were evident in mithun fed R2, R3 and R4 compared to those fed R1. Therefore, it is concluded that TF 25% and/or rice straw 25% along with CM 50% may be fed to the growing mithun for improved rumen ecology, nutrient utilization and thus better performance under stall fed system.  相似文献   

20.
The purpose of this study was to evaluate the effects of sweet potato vine pellet (SWEPP) in concentrate diets on nutrient digestibility and rumen ecology in lactating dairy cows fed on urea-treated rice straw. Three multiparous Holstein crossbred cows in mid-lactation were randomly assigned according to a 3?×?3 Latin square design, and the treatments were as follows: T1 = control (no supplementation), T2 = supplementation of sweet potato vine pellet with 50 g/kg urea (SWEPP I) at 300 g/head/day, and T3 = supplementation of sweet potato pellet with 100 g/kg urea (SWEPP II) at 300 g/head/day, in concentrate diets, respectively. The result revealed that supplementation of SWEPP did not affect feed intake, ruminal pH, and blood urea nitrogen (P?>?0.05). However, apparent digestibilities of organic matter, crude protein, and neutral detergent fiber were higher in SWEPP II than those in others. Furthermore, ruminal ammonia nitrogen (NH3-N) and milk yield were significantly higher (P?<?0.05) in animals fed with SWEPP II than those fed with SWEPP I and control, respectively. In addition, there were no differences in purine derivatives and microbial nitrogen supply among all the treatments. Based on this study, it could be concluded that SWEPP is a good source of supplement which resulted in significant improvement in apparent digestibility, rumen fermentation, and milk yield in lactating dairy cows fed on urea-treated rice straw.  相似文献   

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