Effects of a New Molasses Bvmoduct. Concentrated Separator Byproduct, on NGtrient Digestibility and Ruminal Fermentation in Cattle1f2 R. D. Wiedmeier3, B. H. Tanner, J. R. Bair, H. T. Shenton, M. J. Arambel, and J. L. Walters
ABSTRACT: Continuous chromatographic separator techniques have allowed the extraction of more simple sugars from molasses (MOL). The resultant byproduct, concentrated separator byproduct (CSB), has reduced readily fermentable carbohydrates but elevated CP and mineral content. The feed value of CSB was compared to that of MOL in two separate trials. In Trial 1, a chopped forage mixture containing 8 4 O/O meadow grass hay and 8% alfalfa hay was mixed with either CSB or MOL at 7.3% of DM. Diets were administered to four ruminally cannulated cows in a single reversal design. Digestibility of DM, ADF, NDF, and CP were measured. Ruminal pH, ammonia nitrogen (NH3), VFA, total viable bacteria (TVB), cellulose-xylan fermenting bacteria (CXFB), and ciliated protozoa (PTZI were evaluated. Blood profiles of electrolytes were also measured. Digestibility of DM, ADF, NDF, and CP were 69.03, 68.58; 57.48, 57.77; 65.62, 64.75; and 67.63, 65.07% for the MOL and CSB diets, respectively. Only CP digestibility differed ( P < ,021. Ruminal pH, NH3, VFA, TVB, CXFB, and PTZ were 6.97, 6.93; 14.21, 16.71
mg/dL; 74.30, 74.78 pmol/mL; 26.79, 27.36 x 109/mL; 21.72, 21.36%; and 13.90, 7.80 x 103/mL for the MOL and CSB diets, respectively. Ruminal measurements did not differ. Blood electrolyte profiles were not altered. Trial 2 was similar to Trial 1 except the basal diet used was 4 7 % barley grain, 35% alfalfa hay, and 10% barley straw. Either MOL or CSB was added at 7.3% of the DM. Digestibilities of DM, ADF, NDF, and CP were 69.52, 71.33; 35.96, 37.11; 27.93, 33.47; and 71.10, 73.66% for the MOL and CSB diets, respectively. Digestibility of DM and NDF differed ( P e .Oil Ruminal pH, NH3, VFA, TVB, CB, and PTZ were 6.39, 6.48; 9.93, 9.82 mg/dL; 114.47, 109.84 pmol/mL; 23.46, 23.86 x 109/mL; 6.31, 6.48%; and 13.15, 12.53 x 104/mL for the MOL and CSB diets, respectively. Neither ruminal measurements nor blood electrolyte profiles differed. Substituting CSB for MOL in forage diets had no major effects on nutriture. Substituting CSB for MOL in 50% grain-50% forage diets resulted in a 2.6% increase in DM digestibility, mainly due to improved NDF digestion.
Key Words: Cattle Molasses, Byproducts, Digestibility, Ruminal Fermentation
J. Anim. Sci. 1992. 70:1936-1940
Introduction Molasses (MOL, sugar beet) is a n important byproduct of the sugar production industry that is extensively used in livestock feeding to improve
'Supported in part b y State and Hatch funds allocated to the Utah Agric. Exp. Sta. 2Supported in part b y funds donated b y Amalgamated Sugar, Ogden, UT. 3To whom correspondence should be addressed. Received August 26, 1991. Accepted January 21, 1992.
palatability and to reduce dustiness, and it is a major component of many liquid feed supplements. Molasses is also a concentrated source of readily fermentable carbohydrates in the form of simple sugars (Church, 1986). Newly developed continuous chromatographic separator technologies have made it possible to extract more simple sugars from MOL than previously was practical. The resultant byproduct, contains concentrated separator byproduct (CSB), more CP and ash than conventional MOL. These changes could affect the feeding value of the CSB relative to MOL. The objective of this study was to
1936
Downloaded from https://academic.oup.com/jas/article-abstract/70/6/1936/4631941 by East Carolina University user on 03 January 2019
Department of Animal, Dairy, and Veterinary Sciences, Utah State University, Logan 84322-4815
1937
FEED VALUE OF A NEW MOLASSES BYPRODUCT
Table 1. Nutrient composition of concentrated separator byproduct (CSB) and sugar beet molasses (MOL) Item
CSB %
of DM
-
19.0 0 0 1.30 .57 29.0
8.5 0 0 1.91 1.27 11.3
23.0 .2 4.0
50.0 .1 2.0
&Calculated
compare the effects of supplementing either forage or 50% cereal grain-50% forage diets with either CSB or MOL a t practical levels on nutrient digestibility, ruminal fermentation characteristics, and blood electrolyte profiles.
Materials and Methods Trial 1. A basal diet composed of 8 4 % meadow grass hay and 8% alfalfa hay was prepared by shredding the hays through a 6-cm screen and then mixing them in proper proportions in a screwtype mixing feed wagon. Two test diets were then prepared by slowly adding either CSB or MOL a s the forages mixed. The nutrient composition of the CSB and MOL used are presented in Table 1. Either CSB or MOL was added to the basal diet at
Table 2. Ingredient and nutrient composition of concentrated separator byproduct (CSB) or sugar beet molasses (MOL)-supplemented diets Trial 1 (Forage diet) Item Ingredient Meadow grass hay Alfalfa hay Barley grain Barley straw MOL CSB V-M premixa Plain white salt Nutrient
CP ADF NDF
Trial 2 [Grain-forage diet1
CSB
MOL
84.21 8.05
84.21 8.05
CSB %
-
of DM 35.08 47.39 9.78
7.30
-
MOL -
35.08 47.39 9.78 7.30
7.30 .25 .20
7.30 .25 .20
__
.25 .20
10.80 39.63 63.78
9.80 40.79 63.95
11.75 26.66 34.75
10.65 26.26 33.82
.25 .20
~~
'Vitamin-mineral premix, vitamin A, 500,000 IU/kg, vitamin D,, 50,000 IU/kg; vitamin E, 500 IU/ kg, Zn, 1 6 7 % , Mn. 1.60%; Cu, .4%; I, 200 ppm; Se, 80 ppm. Co, 40 ppm, and P, 12%.
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Nutrient CP, % ADF, % NDF, % NE,", Mcal/kg NEg&, Mcal/kg ASh , % Carbohydrates, g/100 g Sucrose Invert sugars Raffinose
MOL
7.3% of the DM. Diets were fortified with vitamins and minerals using a custom premix. Ingredient and nutrient composition of the diets is presented in Table 2. Diets were fed to four nonpregnant, mature cows (545 to 565 kgl, surgically fitted with ruminal cannulas, in a single reversal design. Surgical procedures used to establish ruminal cannulas were performed by a qualified veterinarian and were reviewed and approved by a n institutional animal care committee working under established guidelines (Consortium, 1988). Cows were individually housed in 4-m x 10-m pens with concrete floors and shelter from wind, rain, and direct sunshine. Pens were bedded with wood shavings a s needed and fresh, clean water was available a t all times. Diets were fed once daily at 0800 at a rate of 11 kg of DM . animal-' d-l for a 14-d adaptation period followed by a 7-d collection period. On d 1 to 5 of the collection period fecal grab samples were taken a t 0800 and 1700. Samples were dried a t 60°C for 72 h and then ground to pass through a 1-mm screen. Fecal samples were then proportionately composited by cow and subsequently analyzed for DM using a forced-air oven a t 100"C for 8 h (AOAC, 1984) and for CP (Hach et al., 19851, ADF (Van Soest, 19671, NDF (Van Soest, 19671, and AIA (Van Keulen and Young, 19771. Acid insoluble ash was used a s a n internal marker to estimate apparent nutrient digestibility. Diet sampling commenced 1 d before the beginning of the collection period and continued daily through the fecal collection period. Diet samples were then ground to pass through a 1-mm screen and proportionately composited by cow. Diet samples were analyzed using procedures similar to those used
1938
WIEDMEIER ET AL.
a continuous flow of oxygen-free C02. Media for growing CXFB contained only noncrystalline cellulose (No. 53755; Sigma Chemical, St. Louis, MO) and xylan (No. X0627, Sigma) as carbohydrate sources, 5 and 2.5 mg/mL of media, respectively. Plates were stored in containers equipped with oxygen scrubbers (BBL Microbiology Systems, Becton, Dickinson, Cockeysville, MD) during incubation (39"C). After incubation all colonies growing on the plates were counted. Trial 2. Experimental procedures and animal management were similar to those used in Trial 1, differing only in the diet used. Different cows were used in Trial 2, although they were the same breed and approximately the same age and weight as those used in Trial 1. In Trial 1, CSB and MOL were tested on a n all-forage diet. In Trial 2, they were tested on a diet that consisted of approximately 50% cereal grain and 50% forage. Alfalfa hay was shredded to pass through a 6-cm screen. Shredded alfalfa hay was then placed in a screwtype mixing feed wagon and either CSB or MOL was slowly added and mixed with the hay. Cows were then fed a n appropriate amount of this mixture along with appropriate amounts of barley straw, barley grain, vitamin-mineral premix, and salt (Table 21. Statistical Analysis. Data were analyzed separately for each trial using analysis of variance with a model appropriate for a single reversal design (SAS, 19851. The model included treatment, period, and cow, and, in the case of ruminal fermentation data, time was included as a covariate. Remainder mean square was used as the error term for all effects in the models. When main effects were different, means were separated using the t-test (Snedecor and Cochran, 1980).
Results and Discussion The CSB and MOL resulted in similar nutrient digestibilities in the all-forage diet used in Trial 1 except for that of CP (Table 3). The MOL diet resulted in a 4 % increase in the proportion of diet CP digested. Because the CSB diet was one percentage point higher in CP, total CP digested was similar between diets. This effect on CP digestibility was not observed in Trial 2 with the 50% grain-50% forage diet. In Trial 2, CSB supplementation resulted in a 2.6% increase in DM digestibility compared with MOL, mainly due to improved fiber digestion. This may have been due to the added buffering action of the minerals associated with the higher ash content of the CSB. Reduction in fiber digestibility measured in diets containing > 25% grain is often associated with reduced ruminal pH (Mould et al., 1983-841, be-
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for fecal samples. Daily rations were consumed readily, so it was not necessary to measure orts. On d 6 of the collection period, blood samples were taken from the tail vein of each cow 4 h postfeeding and immediately taken to a local hospital for automated analysis (Monarch 2000, Instrument Laboratories, Lexington, MA) for electrolyte concentrations (Na, K, C1, Ca, Mg, and PI. Also on d 6, ruminal digesta samples were taken at 0, 2, 4, 6, 8, 10, 12, and 16 h after feeding via the ruminal cannula. Samples were taken from an indwelling polyethylene tube (1 cm i.d. x 1 m long) attached to a .8-kg stainless steel sieve (7-mm openings). One end of the tube was situated through a hole in the ruminal cannula cap and clamped. The other end was attached to the sieve, which was then placed in the rumen. Within a few hours the sieve settled in the area of the cranial pillar. The sampling tube was placed in the rumen approximately 12 h before the beginning of sampling. Samples were drawn from the tube with a suction syringe. This method allowed frequent sampling without undue disturbance of the animals or disruption of ruminal digesta stratification. Samples were immediately analyzed for pH using a combination electrode. A 10-mL aliquot of sample was then fixed with 10 mL of 50% formalin solution and subsequently analyzed for ciliated protozoa concentration by direct microscopic count (Purser and Moir, 1959). Remaining digesta were then strained through eight layers of cheesecloth and 18 mL of strained digesta was acidified with 2 mL of 6 N HCl. Volatile fatty acid concentrations were measured in acidified samples using gas chromatography (5O/O DEGS [diethylene glycol succinate] + lD/o H3P04 on an Anakrom A90/100 Column; Analabs GCM-109, Unit of Foxboro Analytical, North Haven, CT). Ammonia nitrogen (NH31 concentration was also determined in the acidified samples using Nessler's reagent (Hach Technical Center, Hach Company, Loveland, CO1 (AOAC, 1984). On d 7 of the collection period, ruminal digesta samples were taken via the indwelling tube at 0 and 4 h after feeding. A 20-mL sample of unstrained digesta was immediately blended at high speed with 180 mL of anaerobic dilution solution (ADS1 for 60 s in a Waring-type blender. Diluted samples were continuously gassed with oxygenfree C 0 2 during blending. Samples were then serially diluted to using ADS and anaerobic techniques. Concentrations of total viable bacteria (TVB) and cellulose-xylan fermenting bacteria (CXFB) were measured in diluted samples using a n anaerobic plating technique with habitat-simulating media (Leedle and Hespell, 1980). Duplicate plates were inoculated in a glove box infused with
FEED VALUE OF A NEW MOLASSES BYPRODUCT
1939
Table 3. Effects of concentrated separator byproduct (CSB) or sugar beet molasses (MOL) on nutrient digestibility Trial 1 (Forage diet) Item
CSB
MOL
SEMa
-Yo 68.58 55.77 64.75 65.07’
CSB
MOL
SEM
- Oh
69.03 57.48 65.62 67.63’
.45 .70 .58 .95
71.33b 37.11 37.93c 73.66
69.52’ 35.96 33.47b 71.10
.13 .45 .35 1.48
&Standard error of the mean. bzcMeans in the row with different superscripts differ ( P < ,021.
cause fiber-digesting bacteria are sensitive to low ruminal pH (Yokoyama and Johnson, 1988). Although ruminal pH in Trial 2 did not differ (Table 41, the CSB diet tended (P c .lo) to result in a higher pH. Also, the higher soluble sugar content of the MOL diet may have resulted in negative associative effects. Fiber digestibility is usually reduced when the diet is > 25% in nonstructural carbohydrates such as starch or soluble sugars (Allen and Mertens, 19881, not only due to pH reduction but also due to substrate substitution by fiber-digesting bacteria. This fact is somewhat apparent by comparing the fiber digestibilities between Trials 1 and 2, although it should be noted that the same cows were not used in Trials 1 and 2. These factors would not have been as important in the all-forage diet used in Trial 1 because of the inherent buffering capacity of forages and increased salivary production associ-
ated with all-forage diets compared with grainforage mixtures (Froetschel et al., 19891. Treatment had no effect on ruminal NH3 concentrations (Table 4). Concentrations were well above the 5 mg/dL level, noted as being optimum for microbial growth (Satter and Slyter, 19741, in both trials. Treatments had no effect on ruminal VFA concentrations in either trial and no effect on major proportions of VFA in Trial 1 (forage diets). In Trial 2 ( 5 0 % grain diets) CSB resulted in a slight increase in the proportion of acetate and a slight reduction in the proportion of butyrate. Because most butyrate is synthesized from acetate (Owens and Goetsch, 1988) and neither is gluconeogenic, there would probably be little effect on energy budgets. Molasses resulted in a slight increase in the proportion of valerate. Valerate is specifically required by ruminal fiber-digesting bacteria (Bryant, 19731 and can be derived from dietary
Table 4. Effects of concentrated separator byproduct (CSB) or sugar beet molasses (MOL) on ruminal fermentation characteristics Trial 1 (Forage dietl
Trial 2 (Grain-forage diet)
Item
CSB
MOL
SEMa
CSB
MOL
SEM
PH NH,~ VFA, mM
6.93 16.71 74.78
6.97 14.21 74.30
.03 1.25 .52
6.48 9.82 109.84
6.39 9.93 114.47
.05 .69 3.88
71.14 16.48 9.47 .87 1.16 .87 .78 27.36 2 1.36
70.80 16.96 9.34 .87 1.02 .99 1.39 26.79 2 1.72
.92 .39 .23 .o 1
mo1/100 mol
Acetate Propionate Butyrate Isobutyrate Isovalerate Valerate PTZC TVB~ CXFBe
.09 .04 .45 1.23 .86
68.98f 17.00 10.678 .92 1.16 1.19g 12.53 23.86 6.48
&Standard error of the mean. bAmmonia nitrogen, mg/dL. CCiliated protozoa, 10,00O/mL. dTotal viable bacteria, billion/mL. eCellulose-xylan fermenting bacteria, percentage of total. LgMeans in the same row with different superscripts differ (P < .05).
68.15’ 17.06 11.05f .97 1.13 1.26f 13.15 23.46 6.31
.20
.26 .22 .07 .07 .02
.97 .45 .24
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DM ADF NDF CP
Trial 2 (Grain-forage dietl
WIEDMEIER ET AL.
1940
Table 5. Effects of concentrated separator byproduct (CSB) or sugar beet molasses (MOL) on blood electrolyte profiles Trial
1
(Forage diet)
CSB
MOL
Calcium, mg/dL Phosphorus, mg/dL Potassium, pmol/mL Sodium, p o l / m L Magnesium, mg/dL Chloride, p o l / m L
12.01 6.21 6.20 143.29 2.71 102.02
11.62 6.21 5.70 142.34 2.63 101.21
SEMa .4 1 .83 .47 .58 .32 .46
CSB
MOL
10.23 5.75 4.40 146.50 2.58 105.75
10.08 5.58 4.75 148.75 2.55 105.00
SEM .07 .06 .ll 95 .04 1.63
&Standard error of the mean
carbohydrates. The higher carbohydrate content of MOL may account for the slight increase in ruminal valerate. Numbers of protozoa were not affected by treatments. Concentrations were substantially higher in Trial 2 than in Trial 1, which reflected the higher nonstructural carbohydrate component of the diets used in Trial 2. Concentrations of TVB were not affected by treatment in either trial, nor were the proportions of the total that were CXFB. Proportions of CXFB were apparently higher in Trial 1 than in Trial 2, as would be expected with the higher levels of structural carbohydrates in the all-forage diets. The effects of CSB or MOL on blood electrolytes are presented in Table 5. These measurements were made because of concern that the high ash content of CSB would have a n effect on mineral metabolism. Treatments had no effect on blood electrolyte profiles in either trial. All concentrations were within the normal range for the bovine species (Kelley, 19671.
Bryant, M. P. 1973. Nutritional requirements of the predominant rumen cellulolytic bacteria. Fed. Proc. 32: 1809. Church, D. C. 1986. Livestock Feeds and Feeding (2nd Ed.). Prentice-Hall. Englewood Cliffs, NJ. Consortium. 1988. Guide for the Care and Use of Agricultural Animals in Agricultural Research and Teaching. Consortium for Developing a Guide for the Care and Use of Agricultural Animals in Agricultural Research and Teaching. Champaign, IL. Froetschel, M. A,, H. E. Amos, J. J. Evans. W. J. Croom, Jr., and W. M. Hagler, Jr. 1989. Effects of a salivary stimulant, slaframine, on ruminal fermentation, bacterial protein synthesis and digestion in frequently fed steers. J. Anim. Sci. 67:a27.
Literature Cited
Hach, C. C., S. V. Brayton, and A. B. Kopelove. 1985. A powerful kjeldahl nitrogen method using peroxysulfuric acid. J. Agric. Food Chem. 33:1117. Kelly, W. R. 1967. Veterinary Clinical Diagnosis. The Garden City Press, Letchworth, Hertfordshire, UK. Leedle, J.A.Z., and R. B. Hespell. 1980. Differential carbohydrate media and anaerobic replica plating techniques in delineating carbohydrate utilizing subgroups in rumen bacterial populations. Appl. Environ. Microbial 39:709. Mould, F. L., E. R. IZlrskov, and S. 0. Mann. 1983-84. Associative effects of mixed feeds. Effects of type and level of supplementation and the influence of the rumen fluid pH on cellulolysis in vivo and dry matter digestion of various roughages. Anim. Feed Sci. Technol. 10:15. Owens, F. N., and A. L. Goetsch. 1988. Ruminal fermentation. In: D. C. Church (Ed.) The Ruminant Animal-Digestive Physiology and Nutrition. pp 145-171. Prentice-Hall, Englewood Cliffs, NJ. Purser, D. B., and R. J. Moir. 1959. Ruminal flora studies in sheep. IX. The effect of pH on the ciliated population of the rumen in vivo. Aust. J. Agric. Res. 10:555. SAS. 1985. SAS User’s Guide: Statistics. SAS Inst. Inc., Cary, NC. Satter, L. D., and L. L. Slyter. 1974. Effect of ammonia concentration on rumen microbial protein production in vitro. Br. J. Nutr. 32:199. Snedecor, G. W., and W. G. Cochran. 1980. Statistical Methods (7th Ed.). Iowa State University Press, Ames. Van Keulen, J., and B. A. Young. 1977. Evaluation of acidinsoluble ash as a natural marker in ruminant digestibility studies. J. Anim. Sci. 44:282. Van Soest, P. J. 1967. Development of a comprehensive system of feed analysis and its application to forages. J. Anim. Sci.
Allen, M. S., and D. R. Mertens. 1988. Evaluating constraints on fiber digestion by rumen microbes. J. Nutr. 188:261. AOAC. 1984. Official Methods of Analysis (14th Ed.). Association of Official Analytical Chemists, Arlington, VA.
Yokoyama, M. T., and K. A. Johnson. 1988. Microbiology of the rumen and intestine. In. D. C. Church (Ed.) The Ruminant Animal-Digestive Physiology and Nutrition. pp 125-144. Prentice-Hall, Englewood Cliffs, NJ.
Implications Based on the results of these trials, substituting concentrated separator byproduct for molasses on a n equal basis a t practical levels will result in similar nutrient utilization in forage diets and should slightly improve fiber utilization in cereal grain-forage mixtures, possibly due to the buffering action of the increased mineral content of concentrated separator byproduct. Longer-term studies using animals in productive status are needed to further qualify the use of concentrated separator byproduct.
26:119.
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Item
Trial 2 [Grain-forage diet)
ABSTRACT: Continuous chromatographic separator techniques have allowed the extraction of more simple sugars from molasses (MOL). The resultant byproduct, concentrated separator byproduct (CSB), has reduced readily fermentable carbohydrates but elevated CP and mineral content. The feed value of CSB was compared to that of MOL in two separate trials. In Trial 1, a chopped forage mixture containing 8 4 O/O meadow grass hay and 8% alfalfa hay was mixed with either CSB or MOL at 7.3% of DM. Diets were administered to four ruminally cannulated cows in a single reversal design. Digestibility of DM, ADF, NDF, and CP were measured. Ruminal pH, ammonia nitrogen (NH3), VFA, total viable bacteria (TVB), cellulose-xylan fermenting bacteria (CXFB), and ciliated protozoa (PTZI were evaluated. Blood profiles of electrolytes were also measured. Digestibility of DM, ADF, NDF, and CP were 69.03, 68.58; 57.48, 57.77; 65.62, 64.75; and 67.63, 65.07% for the MOL and CSB diets, respectively. Only CP digestibility differed ( P < ,021. Ruminal pH, NH3, VFA, TVB, CXFB, and PTZ were 6.97, 6.93; 14.21, 16.71
mg/dL; 74.30, 74.78 pmol/mL; 26.79, 27.36 x 109/mL; 21.72, 21.36%; and 13.90, 7.80 x 103/mL for the MOL and CSB diets, respectively. Ruminal measurements did not differ. Blood electrolyte profiles were not altered. Trial 2 was similar to Trial 1 except the basal diet used was 4 7 % barley grain, 35% alfalfa hay, and 10% barley straw. Either MOL or CSB was added at 7.3% of the DM. Digestibilities of DM, ADF, NDF, and CP were 69.52, 71.33; 35.96, 37.11; 27.93, 33.47; and 71.10, 73.66% for the MOL and CSB diets, respectively. Digestibility of DM and NDF differed ( P e .Oil Ruminal pH, NH3, VFA, TVB, CB, and PTZ were 6.39, 6.48; 9.93, 9.82 mg/dL; 114.47, 109.84 pmol/mL; 23.46, 23.86 x 109/mL; 6.31, 6.48%; and 13.15, 12.53 x 104/mL for the MOL and CSB diets, respectively. Neither ruminal measurements nor blood electrolyte profiles differed. Substituting CSB for MOL in forage diets had no major effects on nutriture. Substituting CSB for MOL in 50% grain-50% forage diets resulted in a 2.6% increase in DM digestibility, mainly due to improved NDF digestion.
Key Words: Cattle Molasses, Byproducts, Digestibility, Ruminal Fermentation
J. Anim. Sci. 1992. 70:1936-1940
Introduction Molasses (MOL, sugar beet) is a n important byproduct of the sugar production industry that is extensively used in livestock feeding to improve
'Supported in part b y State and Hatch funds allocated to the Utah Agric. Exp. Sta. 2Supported in part b y funds donated b y Amalgamated Sugar, Ogden, UT. 3To whom correspondence should be addressed. Received August 26, 1991. Accepted January 21, 1992.
palatability and to reduce dustiness, and it is a major component of many liquid feed supplements. Molasses is also a concentrated source of readily fermentable carbohydrates in the form of simple sugars (Church, 1986). Newly developed continuous chromatographic separator technologies have made it possible to extract more simple sugars from MOL than previously was practical. The resultant byproduct, contains concentrated separator byproduct (CSB), more CP and ash than conventional MOL. These changes could affect the feeding value of the CSB relative to MOL. The objective of this study was to
1936
Downloaded from https://academic.oup.com/jas/article-abstract/70/6/1936/4631941 by East Carolina University user on 03 January 2019
Department of Animal, Dairy, and Veterinary Sciences, Utah State University, Logan 84322-4815
1937
FEED VALUE OF A NEW MOLASSES BYPRODUCT
Table 1. Nutrient composition of concentrated separator byproduct (CSB) and sugar beet molasses (MOL) Item
CSB %
of DM
-
19.0 0 0 1.30 .57 29.0
8.5 0 0 1.91 1.27 11.3
23.0 .2 4.0
50.0 .1 2.0
&Calculated
compare the effects of supplementing either forage or 50% cereal grain-50% forage diets with either CSB or MOL a t practical levels on nutrient digestibility, ruminal fermentation characteristics, and blood electrolyte profiles.
Materials and Methods Trial 1. A basal diet composed of 8 4 % meadow grass hay and 8% alfalfa hay was prepared by shredding the hays through a 6-cm screen and then mixing them in proper proportions in a screwtype mixing feed wagon. Two test diets were then prepared by slowly adding either CSB or MOL a s the forages mixed. The nutrient composition of the CSB and MOL used are presented in Table 1. Either CSB or MOL was added to the basal diet at
Table 2. Ingredient and nutrient composition of concentrated separator byproduct (CSB) or sugar beet molasses (MOL)-supplemented diets Trial 1 (Forage diet) Item Ingredient Meadow grass hay Alfalfa hay Barley grain Barley straw MOL CSB V-M premixa Plain white salt Nutrient
CP ADF NDF
Trial 2 [Grain-forage diet1
CSB
MOL
84.21 8.05
84.21 8.05
CSB %
-
of DM 35.08 47.39 9.78
7.30
-
MOL -
35.08 47.39 9.78 7.30
7.30 .25 .20
7.30 .25 .20
__
.25 .20
10.80 39.63 63.78
9.80 40.79 63.95
11.75 26.66 34.75
10.65 26.26 33.82
.25 .20
~~
'Vitamin-mineral premix, vitamin A, 500,000 IU/kg, vitamin D,, 50,000 IU/kg; vitamin E, 500 IU/ kg, Zn, 1 6 7 % , Mn. 1.60%; Cu, .4%; I, 200 ppm; Se, 80 ppm. Co, 40 ppm, and P, 12%.
Downloaded from https://academic.oup.com/jas/article-abstract/70/6/1936/4631941 by East Carolina University user on 03 January 2019
Nutrient CP, % ADF, % NDF, % NE,", Mcal/kg NEg&, Mcal/kg ASh , % Carbohydrates, g/100 g Sucrose Invert sugars Raffinose
MOL
7.3% of the DM. Diets were fortified with vitamins and minerals using a custom premix. Ingredient and nutrient composition of the diets is presented in Table 2. Diets were fed to four nonpregnant, mature cows (545 to 565 kgl, surgically fitted with ruminal cannulas, in a single reversal design. Surgical procedures used to establish ruminal cannulas were performed by a qualified veterinarian and were reviewed and approved by a n institutional animal care committee working under established guidelines (Consortium, 1988). Cows were individually housed in 4-m x 10-m pens with concrete floors and shelter from wind, rain, and direct sunshine. Pens were bedded with wood shavings a s needed and fresh, clean water was available a t all times. Diets were fed once daily at 0800 at a rate of 11 kg of DM . animal-' d-l for a 14-d adaptation period followed by a 7-d collection period. On d 1 to 5 of the collection period fecal grab samples were taken a t 0800 and 1700. Samples were dried a t 60°C for 72 h and then ground to pass through a 1-mm screen. Fecal samples were then proportionately composited by cow and subsequently analyzed for DM using a forced-air oven a t 100"C for 8 h (AOAC, 1984) and for CP (Hach et al., 19851, ADF (Van Soest, 19671, NDF (Van Soest, 19671, and AIA (Van Keulen and Young, 19771. Acid insoluble ash was used a s a n internal marker to estimate apparent nutrient digestibility. Diet sampling commenced 1 d before the beginning of the collection period and continued daily through the fecal collection period. Diet samples were then ground to pass through a 1-mm screen and proportionately composited by cow. Diet samples were analyzed using procedures similar to those used
1938
WIEDMEIER ET AL.
a continuous flow of oxygen-free C02. Media for growing CXFB contained only noncrystalline cellulose (No. 53755; Sigma Chemical, St. Louis, MO) and xylan (No. X0627, Sigma) as carbohydrate sources, 5 and 2.5 mg/mL of media, respectively. Plates were stored in containers equipped with oxygen scrubbers (BBL Microbiology Systems, Becton, Dickinson, Cockeysville, MD) during incubation (39"C). After incubation all colonies growing on the plates were counted. Trial 2. Experimental procedures and animal management were similar to those used in Trial 1, differing only in the diet used. Different cows were used in Trial 2, although they were the same breed and approximately the same age and weight as those used in Trial 1. In Trial 1, CSB and MOL were tested on a n all-forage diet. In Trial 2, they were tested on a diet that consisted of approximately 50% cereal grain and 50% forage. Alfalfa hay was shredded to pass through a 6-cm screen. Shredded alfalfa hay was then placed in a screwtype mixing feed wagon and either CSB or MOL was slowly added and mixed with the hay. Cows were then fed a n appropriate amount of this mixture along with appropriate amounts of barley straw, barley grain, vitamin-mineral premix, and salt (Table 21. Statistical Analysis. Data were analyzed separately for each trial using analysis of variance with a model appropriate for a single reversal design (SAS, 19851. The model included treatment, period, and cow, and, in the case of ruminal fermentation data, time was included as a covariate. Remainder mean square was used as the error term for all effects in the models. When main effects were different, means were separated using the t-test (Snedecor and Cochran, 1980).
Results and Discussion The CSB and MOL resulted in similar nutrient digestibilities in the all-forage diet used in Trial 1 except for that of CP (Table 3). The MOL diet resulted in a 4 % increase in the proportion of diet CP digested. Because the CSB diet was one percentage point higher in CP, total CP digested was similar between diets. This effect on CP digestibility was not observed in Trial 2 with the 50% grain-50% forage diet. In Trial 2, CSB supplementation resulted in a 2.6% increase in DM digestibility compared with MOL, mainly due to improved fiber digestion. This may have been due to the added buffering action of the minerals associated with the higher ash content of the CSB. Reduction in fiber digestibility measured in diets containing > 25% grain is often associated with reduced ruminal pH (Mould et al., 1983-841, be-
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for fecal samples. Daily rations were consumed readily, so it was not necessary to measure orts. On d 6 of the collection period, blood samples were taken from the tail vein of each cow 4 h postfeeding and immediately taken to a local hospital for automated analysis (Monarch 2000, Instrument Laboratories, Lexington, MA) for electrolyte concentrations (Na, K, C1, Ca, Mg, and PI. Also on d 6, ruminal digesta samples were taken at 0, 2, 4, 6, 8, 10, 12, and 16 h after feeding via the ruminal cannula. Samples were taken from an indwelling polyethylene tube (1 cm i.d. x 1 m long) attached to a .8-kg stainless steel sieve (7-mm openings). One end of the tube was situated through a hole in the ruminal cannula cap and clamped. The other end was attached to the sieve, which was then placed in the rumen. Within a few hours the sieve settled in the area of the cranial pillar. The sampling tube was placed in the rumen approximately 12 h before the beginning of sampling. Samples were drawn from the tube with a suction syringe. This method allowed frequent sampling without undue disturbance of the animals or disruption of ruminal digesta stratification. Samples were immediately analyzed for pH using a combination electrode. A 10-mL aliquot of sample was then fixed with 10 mL of 50% formalin solution and subsequently analyzed for ciliated protozoa concentration by direct microscopic count (Purser and Moir, 1959). Remaining digesta were then strained through eight layers of cheesecloth and 18 mL of strained digesta was acidified with 2 mL of 6 N HCl. Volatile fatty acid concentrations were measured in acidified samples using gas chromatography (5O/O DEGS [diethylene glycol succinate] + lD/o H3P04 on an Anakrom A90/100 Column; Analabs GCM-109, Unit of Foxboro Analytical, North Haven, CT). Ammonia nitrogen (NH31 concentration was also determined in the acidified samples using Nessler's reagent (Hach Technical Center, Hach Company, Loveland, CO1 (AOAC, 1984). On d 7 of the collection period, ruminal digesta samples were taken via the indwelling tube at 0 and 4 h after feeding. A 20-mL sample of unstrained digesta was immediately blended at high speed with 180 mL of anaerobic dilution solution (ADS1 for 60 s in a Waring-type blender. Diluted samples were continuously gassed with oxygenfree C 0 2 during blending. Samples were then serially diluted to using ADS and anaerobic techniques. Concentrations of total viable bacteria (TVB) and cellulose-xylan fermenting bacteria (CXFB) were measured in diluted samples using a n anaerobic plating technique with habitat-simulating media (Leedle and Hespell, 1980). Duplicate plates were inoculated in a glove box infused with
FEED VALUE OF A NEW MOLASSES BYPRODUCT
1939
Table 3. Effects of concentrated separator byproduct (CSB) or sugar beet molasses (MOL) on nutrient digestibility Trial 1 (Forage diet) Item
CSB
MOL
SEMa
-Yo 68.58 55.77 64.75 65.07’
CSB
MOL
SEM
- Oh
69.03 57.48 65.62 67.63’
.45 .70 .58 .95
71.33b 37.11 37.93c 73.66
69.52’ 35.96 33.47b 71.10
.13 .45 .35 1.48
&Standard error of the mean. bzcMeans in the row with different superscripts differ ( P < ,021.
cause fiber-digesting bacteria are sensitive to low ruminal pH (Yokoyama and Johnson, 1988). Although ruminal pH in Trial 2 did not differ (Table 41, the CSB diet tended (P c .lo) to result in a higher pH. Also, the higher soluble sugar content of the MOL diet may have resulted in negative associative effects. Fiber digestibility is usually reduced when the diet is > 25% in nonstructural carbohydrates such as starch or soluble sugars (Allen and Mertens, 19881, not only due to pH reduction but also due to substrate substitution by fiber-digesting bacteria. This fact is somewhat apparent by comparing the fiber digestibilities between Trials 1 and 2, although it should be noted that the same cows were not used in Trials 1 and 2. These factors would not have been as important in the all-forage diet used in Trial 1 because of the inherent buffering capacity of forages and increased salivary production associ-
ated with all-forage diets compared with grainforage mixtures (Froetschel et al., 19891. Treatment had no effect on ruminal NH3 concentrations (Table 4). Concentrations were well above the 5 mg/dL level, noted as being optimum for microbial growth (Satter and Slyter, 19741, in both trials. Treatments had no effect on ruminal VFA concentrations in either trial and no effect on major proportions of VFA in Trial 1 (forage diets). In Trial 2 ( 5 0 % grain diets) CSB resulted in a slight increase in the proportion of acetate and a slight reduction in the proportion of butyrate. Because most butyrate is synthesized from acetate (Owens and Goetsch, 1988) and neither is gluconeogenic, there would probably be little effect on energy budgets. Molasses resulted in a slight increase in the proportion of valerate. Valerate is specifically required by ruminal fiber-digesting bacteria (Bryant, 19731 and can be derived from dietary
Table 4. Effects of concentrated separator byproduct (CSB) or sugar beet molasses (MOL) on ruminal fermentation characteristics Trial 1 (Forage dietl
Trial 2 (Grain-forage diet)
Item
CSB
MOL
SEMa
CSB
MOL
SEM
PH NH,~ VFA, mM
6.93 16.71 74.78
6.97 14.21 74.30
.03 1.25 .52
6.48 9.82 109.84
6.39 9.93 114.47
.05 .69 3.88
71.14 16.48 9.47 .87 1.16 .87 .78 27.36 2 1.36
70.80 16.96 9.34 .87 1.02 .99 1.39 26.79 2 1.72
.92 .39 .23 .o 1
mo1/100 mol
Acetate Propionate Butyrate Isobutyrate Isovalerate Valerate PTZC TVB~ CXFBe
.09 .04 .45 1.23 .86
68.98f 17.00 10.678 .92 1.16 1.19g 12.53 23.86 6.48
&Standard error of the mean. bAmmonia nitrogen, mg/dL. CCiliated protozoa, 10,00O/mL. dTotal viable bacteria, billion/mL. eCellulose-xylan fermenting bacteria, percentage of total. LgMeans in the same row with different superscripts differ (P < .05).
68.15’ 17.06 11.05f .97 1.13 1.26f 13.15 23.46 6.31
.20
.26 .22 .07 .07 .02
.97 .45 .24
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DM ADF NDF CP
Trial 2 (Grain-forage dietl
WIEDMEIER ET AL.
1940
Table 5. Effects of concentrated separator byproduct (CSB) or sugar beet molasses (MOL) on blood electrolyte profiles Trial
1
(Forage diet)
CSB
MOL
Calcium, mg/dL Phosphorus, mg/dL Potassium, pmol/mL Sodium, p o l / m L Magnesium, mg/dL Chloride, p o l / m L
12.01 6.21 6.20 143.29 2.71 102.02
11.62 6.21 5.70 142.34 2.63 101.21
SEMa .4 1 .83 .47 .58 .32 .46
CSB
MOL
10.23 5.75 4.40 146.50 2.58 105.75
10.08 5.58 4.75 148.75 2.55 105.00
SEM .07 .06 .ll 95 .04 1.63
&Standard error of the mean
carbohydrates. The higher carbohydrate content of MOL may account for the slight increase in ruminal valerate. Numbers of protozoa were not affected by treatments. Concentrations were substantially higher in Trial 2 than in Trial 1, which reflected the higher nonstructural carbohydrate component of the diets used in Trial 2. Concentrations of TVB were not affected by treatment in either trial, nor were the proportions of the total that were CXFB. Proportions of CXFB were apparently higher in Trial 1 than in Trial 2, as would be expected with the higher levels of structural carbohydrates in the all-forage diets. The effects of CSB or MOL on blood electrolytes are presented in Table 5. These measurements were made because of concern that the high ash content of CSB would have a n effect on mineral metabolism. Treatments had no effect on blood electrolyte profiles in either trial. All concentrations were within the normal range for the bovine species (Kelley, 19671.
Bryant, M. P. 1973. Nutritional requirements of the predominant rumen cellulolytic bacteria. Fed. Proc. 32: 1809. Church, D. C. 1986. Livestock Feeds and Feeding (2nd Ed.). Prentice-Hall. Englewood Cliffs, NJ. Consortium. 1988. Guide for the Care and Use of Agricultural Animals in Agricultural Research and Teaching. Consortium for Developing a Guide for the Care and Use of Agricultural Animals in Agricultural Research and Teaching. Champaign, IL. Froetschel, M. A,, H. E. Amos, J. J. Evans. W. J. Croom, Jr., and W. M. Hagler, Jr. 1989. Effects of a salivary stimulant, slaframine, on ruminal fermentation, bacterial protein synthesis and digestion in frequently fed steers. J. Anim. Sci. 67:a27.
Literature Cited
Hach, C. C., S. V. Brayton, and A. B. Kopelove. 1985. A powerful kjeldahl nitrogen method using peroxysulfuric acid. J. Agric. Food Chem. 33:1117. Kelly, W. R. 1967. Veterinary Clinical Diagnosis. The Garden City Press, Letchworth, Hertfordshire, UK. Leedle, J.A.Z., and R. B. Hespell. 1980. Differential carbohydrate media and anaerobic replica plating techniques in delineating carbohydrate utilizing subgroups in rumen bacterial populations. Appl. Environ. Microbial 39:709. Mould, F. L., E. R. IZlrskov, and S. 0. Mann. 1983-84. Associative effects of mixed feeds. Effects of type and level of supplementation and the influence of the rumen fluid pH on cellulolysis in vivo and dry matter digestion of various roughages. Anim. Feed Sci. Technol. 10:15. Owens, F. N., and A. L. Goetsch. 1988. Ruminal fermentation. In: D. C. Church (Ed.) The Ruminant Animal-Digestive Physiology and Nutrition. pp 145-171. Prentice-Hall, Englewood Cliffs, NJ. Purser, D. B., and R. J. Moir. 1959. Ruminal flora studies in sheep. IX. The effect of pH on the ciliated population of the rumen in vivo. Aust. J. Agric. Res. 10:555. SAS. 1985. SAS User’s Guide: Statistics. SAS Inst. Inc., Cary, NC. Satter, L. D., and L. L. Slyter. 1974. Effect of ammonia concentration on rumen microbial protein production in vitro. Br. J. Nutr. 32:199. Snedecor, G. W., and W. G. Cochran. 1980. Statistical Methods (7th Ed.). Iowa State University Press, Ames. Van Keulen, J., and B. A. Young. 1977. Evaluation of acidinsoluble ash as a natural marker in ruminant digestibility studies. J. Anim. Sci. 44:282. Van Soest, P. J. 1967. Development of a comprehensive system of feed analysis and its application to forages. J. Anim. Sci.
Allen, M. S., and D. R. Mertens. 1988. Evaluating constraints on fiber digestion by rumen microbes. J. Nutr. 188:261. AOAC. 1984. Official Methods of Analysis (14th Ed.). Association of Official Analytical Chemists, Arlington, VA.
Yokoyama, M. T., and K. A. Johnson. 1988. Microbiology of the rumen and intestine. In. D. C. Church (Ed.) The Ruminant Animal-Digestive Physiology and Nutrition. pp 125-144. Prentice-Hall, Englewood Cliffs, NJ.
Implications Based on the results of these trials, substituting concentrated separator byproduct for molasses on a n equal basis a t practical levels will result in similar nutrient utilization in forage diets and should slightly improve fiber utilization in cereal grain-forage mixtures, possibly due to the buffering action of the increased mineral content of concentrated separator byproduct. Longer-term studies using animals in productive status are needed to further qualify the use of concentrated separator byproduct.
26:119.
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Item
Trial 2 [Grain-forage diet)
