COMBINATION AND METHOD FOR INCREASING FEED UTILIZATION EFFIENCY IN RUMINANTS

Abstract: A composition useful for enhancing the efficiency of feed utilization in ruminants comprising as a first component a propionate-increasing amount of a polyether antibiotic and a second component which is a glycopeptide antibiotic said components being present in amounts which, in combina­ tion, are synergistic to ruminant propionate increase.

Description: COMBINATION D METHOD FOR INCREASING FEED UTILIZATION EFFTCIENCY IN RUMINANTS A rumer of chemical agents are known which are effective in increasing the efficiency of feed utilization by ruminants. Monensin, for Instance, has found widespread success in promoting feed efficiecy in ruminants such as cattle and sheep. Monensin, and numerous other polyether antibiotics and related conpounds, function by altering the mechanism of runirJant fed utilization, which mechanism involves ermentation. Microorganisms in the developed rumen cf a ruminant animal degrade carbohydrates (the major nutritive portion of ruminant feeds) to produce pyruvates. Pyruvates are further metabolized by microbiological processes to form acetates, butyrates and propionates. These latter compounds are collectively referred to as volatile fatty acids (VFA's). While acetates, butyrates and propionates all are utilized in the growth mechanism and in energy production, the propionates are more efficiently produced and utilized than either the acetates or the butyrates. Some of the known growth promoters and feed utilization enhancers thus function in ruminants having a developed rumen function by increasing the formation of propionates from carbo ;hydrates, at the expense of acetate and butyrate pro duction. Raun et al., in J. Ani. Sci.,-43, 670 (1976), demonstrate that the effectiveness of monensin on feed efficiency reaches a maximum at a dose level of about 39 grams per ton of feed. A similar maximum in effc- tiveness at a particular dose level is observed with most other feed efficiency enhancers, including the glycopeptides such as avoparcin, actaplanin and the like. This maximum effectiveness has been considered due to an inability to increase propionate production in the rumen beyond a certain level. It therefore is surprising that the administration of a combination of feed efficiency enhancing agents selected from a glycopeptide and a polyether to an animal having a developed rumen function causes a greater effect upon feed efficiency (i.e., a greater production of propionate) than effected by either agent when administered alone at an optimal dose level. An object of this invention is to provide a synergistic combination of feed efficiency enhancing agents which is surprisingly effective in increasing the efficiency of feed utilization in such animals. This invention relates to a combination of active ingredients useful in promoting growth and increasing feed utilization efficiency in ruminants, and to a method for increasing the efficiency of feed utilization in ruminants utilizing such combination. The invention is more particularly directed to a composition comprised of a propionate increasing amount of a polyether antibiotic in combination with a propionate increasing amount of a glycopeptide. The compositions of this invention are synergistic. The invention additionally provides a method for increasing the efficiency of feed utilization by runinants comprising orally administering to an animal having a developed rumen function a propionate increas ing amount of the combination of a polyether antibiotic and a glycopeptide antibiotic. The compounds to be employed in the composi tions provided by this invention are well known in the art. A number of such compounds are in commercial use. The polyether antibiotics to be employed according to this invention are a class of antibiotics produced by the Streptomyces genus of microorganisms. They are characterized by comprising a multiplicity of cyclic ethers in their structures. The class is re viewed in Kirk-Othmer: Encyclopedia of Chemical Tech nology, Vol. 3, Third Edition (John Wiley & Sons, Ind., 1978), page 47 et seq.; in Annual Reports in Medical Chemistry Volume 10 (Academic Press, N.Y. 1975), page 246 et seq.; and in J. Chrom. Lib.,.Vol. 15 (Elsevier Scientific Publishing Co., N.Y. 1978), page 488 et sea. Like other products of fermentation ori in, ,many of the polyether antibiotics comprise more than one factor. The various factors are all usable in the present invention. Further, many of these anti biotics readily form ethers, esters, salts, or other derivatives, which are either active as such or are converted in vivo to the basic antibiotic. Such deriva tives can also be employed in the present invention. All that is necessary is that an active moiety of a polyether antibiotic which is effective in increasing propionate production in a developed rumen be delivered in vivo. Representative of the polyether antibiotics to be employed in the combination of this invention include ruminal propionate enhancers such as monensin (including the various factors A, B, and C, and the alkali metal salts, for instance monensin sodium, and the various esters thereof), ionomycin, laidlomycin, nigericin, grisorixin, dianemycin, Compound 51,532, lenoremycin, salinomycin, narasin, lonomycin, antibiotic X206, alborixin, septamycin, antibiotic A204, Compound 47,224, etheromycin, lasalocid (factors A, B, C, D, and E), mutalomycin, R41, isolasalocid A, lysocellin, and antibiotics X-14766A, A23187 and A32887. Preferred polyether antibiotics include monensin, narasin, lasalocid, salinomycin, A-204, lonomycin, X-206, nigericin, and dianemycin, and especially monensin, narasin, lasalocid and Salinomycin. An especially preferred polyether to be utilized according to this invention is monensin, a compound widely used in the improvement of feed utilization in ruminants (see U.S. Patent No. 3,839,557). As used herein, "monensin" includes the various active factors, the salts such as monensin sodium, and the monensin esters such as carbamate esters and the like. Like the polyether antibiotics mentioned hereinabove, the glycopeptide ruminal propionate enhancers to be employed in the combination of this invention are well known to those skilled in the art. Typical of such glycopeptide feed utilization efficiency enhancers are actaplanin, avoparcin, A35512, A477, ristocetin, vancomycin, and related glycopeptides. Preferred glycopeptides to be employed in the combinations of this invention include actaplanin, avoparacin, ristocetin, and vancomycin. A particularly preferred composition contemplated by this invention includes as one component the polyether antibiotic monensin, in combination with a synergistic amount of a glycopeptide selected from actaplanin and avoparacin. The most preferred combination provided herein is monensin and actaplanin. As hereinabove pointed out, the components of the compositions provided herein are well known in the art, and many are widely used commercially. Monensin, for instance, was first disclosed in U.S. Patent No. 3,501,568. Salts and esters of monensin, as well as the use thereof for increasing feed efficiency in ruminants, is described in U.S. Patent No. 3,839,557. A number of carbamate esters of monensin which are useful in growth promotion are described in European Patent No. 11-859. All of these references, as well as those recited hereinafter, are incorporated herein by reference for their disclosure of the active components of the compositions of this invention and the use of the individual components in improving feed utilization efficiency in ruminants. U.S. Patent No. 3,794,732 describes the polyether antibiotics A204, lasalocid (X-537A), dianemycin, monensin, nigericin and X-206, and their use in the improvement of ruminant feed utilization, lonomycin is a polyether obtained by cultivating the microorganism Streptomyces conglobatus ATOC No. 31005. The production of ionomycin and its properties are described in detail in U.S. Patent No. 3,873,693. The antimycoplasmal polyether antibiotic laidlomycin is produced by cultivating a strain of Streptomyces curocidicus. Laidlomycin is described by Kitame et al. in J. Antibiot., 27, 884-888 (1974). Grisorixin is a polyether antibiotic which is also known as deoxynigericin. As already noted, nigericin is described in U.S. Patent No. 3,794,732. The preparation of deoxynigericin, or grisorixin, is carried out as discussed in French Patent No. 2,097,053. Cultivation of a microorganism belonging to the Streptomyces hydroscopicus species, ATCC No. 21840, produces the polyether known as lenoremycin, also referred to as "antibiotic A-130A". The properties of this antibiotic are detailed in U.S. Patent No. 3,903,264. U.S. Patent Nos. 4,038,384 and 4,085,224 describe the preparation and use of narasin and salinomycin. Narasin is referred to therein as A-28086. Lonomycin is a polyether antibiotic produced from Streptomyces ribosidificus, ATCC No. 31051. The compound, also known as "antibiotic TM 481", "antibiotic DE 3936" and "emericid" is described in detail in 3 J. Antibiotics, 29, No. 1, 15-20 (1976). Deriva- tives of lonomycin are described in U.S. Patent No. 4,199,515. Cultivation of Streptomyces hygroscopicus NRRL 5077 produces the polyether antibiotic known as alborixin, also referred to as "S 14750/A". Alborixin is described in British Patent No. 1,541,485. Septamycin is the name given to a group of antibiotics initially referred to as "antibiotics A28695A and A2869DB" and also known as "BL580". The polyether is produced by culturing Streptomyces albus strain NRRL 3883. The process for preparing septamycin is disclosed in U.S. Patent Nos. 3,839,558 and 4,189,537. Lasalocid is a polyether antibiotic designated as "antibiotic X-537A" and prepared by cultivation of Streptomyces NRRL 3382. The antibiotic is comprised of several factors. Lasalocid and derivatives thereof are described in U.S. Patent No. 3,715,372. Iso-lasalocid A is an isomer of lasalocid A as described in U.S. Patent No. 3,944,573. U.S. Patent No. 4,129,578 refers to several members of the class of polycyclic ether antibiotics. The reference is specifically directed to etheromycin, a compound also known as "antibiotic 38295" and "CP 38295". The compound is valuable as a ruminant growth promoting agent. Mutalamycin is a polyether derivative of lonomycin and is described in Belgian Patent No. 845,708. The compound is also known as "antibiotic S 11743A". Cultivation of Streptomyces hydroscopicus ATCC 31,227 produces a polyether known as antibiotic K-41. The compound is described in British Patent No. 2,028,134 and J. Antibiotics, 29, 10-14 (1976). Other designations for K-41 include "antibiotic 37454RP". Lysocellin is produced by cultivation of Streptomyces longwoodensis ATCC 29,251. Such preparation is described in U.S. Patent No. 4,033,823. Antibiotic A23187 is described in U.S. Patent No. 3,923,823. This polyether antibiotic is also known as "A23187", "lonophore A23187" and "Calcimycin". The compound is produced from Streptomyces chartreusis NRRL 3882. Submerged aerobic fermentation of Streptomyces albus NRRL 11,109 produces antibiotic A-32887. As noted in U.S. Patent No. 4,132,778, this polyether antibiotic and its various derivatives are useful in increasing feed utilization efficiency in ruminants. U.S. Patent No. 4,221,724 describes a new polyether ionophore antibiotic referred to as antibiotic X-14766A. This compound prevents and treats ketosis as well as improves feed utilization in ruminants. U.S. Patent Nos. 4,150,152 and 4,195,079 describe, respectively, new polyethers referred to as "Compound 47,224" and "Compound 51,532". These antibiotics appear to resemble polycyclic ethers such as monensin, nigericin, grisorixin, dianemycin and salinomycin. The polyether antibiotics such as those described above are employed in combination with a glycopeptide antibiotic which is known to increase ruminant feed utilization efficiency. The latter compounds comprise a known class of water-soluble glycopeptide antibiotics active against gram-positive bacteria. U.S. Patent No. 3,928,571 describes the use of various members of the glycopeptide class in the improvement of ruminant feed utilization. Specifically described are the antibiotics known as A477, A-4696 (also known as actaplanin), vancomycin, and ristocetin. The glycopeptide antibiotics A-35512 are a closely related group of factors produced by fermentation of Streptomyces candidus NRRL 8156. A-35512 is discussed in detail in U.S. Patent No. 4,083,964. This group of antibiotics also is closely related to the glycopeptide AV290, which is also now known as avoparcin. Avoparcin is also a complex of antibiotics, but is composed primarily of two main factors. The production of avoparcin is described in U.S. Patent No. 3,338,786, and its structure is discussed by McGahren et al. in J. Am. Chem. Soc., 102, 1671-1680 (1980). As already pointed out, this invention provides a composition comprising a polyether antibiotic and a glycopeptide antibiotic. The components of the present composition are employed in amounts which, in combination, are synergistic. The composition causes the production of a larger amount of propionate in the rumen of an animal having a developed rumen function than caused by either active component when administered alone at its optimal dose level. The net affect of such unexpected increase in propionate production is a correspondingly unexpected increase in the efficient of feed utilization. The compositions provided herein comprise a polyether as defined above and a synergistic amount of a glycopeptide as defined above. The respective component will preferably be present qn a weiqht basis in a ratio of about 1 to about 10 parts polyether together with about 1 to about 10 parts glycopeptide. Typically, the maximal doses of each component to be employed in accordance with the present invention are substantially the same as the maximal doses for effective growth promotion and feed utilization enhancement by the individual components. For example, monensin has been demonstrated to cause a maximal improvement in feed efficiency at a dose level of about 30 grams per ton of feed, or a dosage level of about 11 ppm (see Raun et al., J. Ani. Sci. 43, 670 (1976)). Similarly, actaplanin at a dose of about 30 grams per ton of feed effects the largest increase in propionate production observed with that agent. According to the present invention, there is thus provided a preferred combination comprising monensin as a first component, ideally commercial monensin sodium which includes primarily factor A with a small amount of factor B, and actaplanin as a second component. Normally such combination will be added to a ruminant feedstuff such that the dose level is about 15 to about 50 grams per ton of monensin and about 15 to about 50 grams per ton of actaplanin. A preferred combination according to this invention comprises about 30 grams of monensin and about 30 grams of actaplanin, said dose of combination being administered per ton of feedstuff. Additional exemplary combinations provided by this invention include the following, which are presented in grams of each component, said combination to be administered per ton of animal feedstuff. 30 grams monensin - 40 grams avoparcin; 20 grams monensin - 40 grams ristocetin; 35 grams monensin - 30 grams vancomycin; 20 grams narasin - 20 grams actaplanin; 25 grams narasin - 30 grams avoparcin; 40 grams lasalocid - 30 grams actaplanin; 20 grams lasalocid - 25 grams avoparcin; 30 grams dianemycin - 30 grams actaplanin; 45 grams dianemycin - 25 grams A477; 50 grams alborixin - 20 grams avoparcin; 60 grams alborixin - 10 grams vancomycin; 10 grams ionomycin - 20 grams actaplanin; 25 grams ionomycin - 30 grams A35512; 40 grams septamycin - 50 grams ristocetin; 60 grams septamycin - 20 grams A35512 28 grams etheromycin - 32 grams actaplanin; 15 grams lysocellin -20 grams ristocetin; 30 grams lysocellin -25 grams actaplanin; 30 grams lysocellin - 30 grams avoparacin; 12 grams isolasalocid A - 24 grams avoparcin; 20 grams isolasalocid A - 30 grams actaplanin; ; 50 grams A-204 - 20 grams ristocetin; 60 grams K41 - 40 grams actaplanin; 22 grams lonomycin - 44 grams An35312; 40 grams lonomycin - 20 grams An477; 20 grams dianemycin - 20 grams avoparcin; 30 grams salinomycin - 20 grams vancomycin; 40 grams salinomycin - 20 grams actaplanin; 30 grams lenoremycin - 30 grams avoparcin; are related combinations. The combination provided by this invention can be administered to ruminant animals orally, for example by being admixed with a suitable carrier such as a normal daily ruminant feed regimen. Such method is especially preferred for feeder calves at the feedlot stage of development. A typical high-grain feedstuff for feed lot animals has the following composition. Ingredient Percent Coarse ground corn 69.95 Ground corncobs 10.00 Soybean meal (50% protein) 8.00 Alfalfa meal 5.00 Molasses 5.00 Urea 0.60 Dicalcium phosphate 0.50 Calcium carbonate 0.50 Salt 0.30 Vitamin A and D2 premix 0.07 Vitamin E premix 0.05 Trace mineral premix 0.03 100.0 A combination of this invention, for instance a 1:1 combination of monensin and avoparcin, is then added to such feedstuf at the rate of about 40 to about 100 grams of such combination per ton of feed stuff. Such feedstuff then is administered to the ruminant animals at the rate of about 5 to about 30 pounds each day. Such treatment effects an increased rate of feed utilization and promotes growth. The combinations provided by this invention can also be utilized with feed rations such as grass, silage, and the like, and can be administered to range fed unconfined animals as well as to confined feedlot animals. An alternative and often preferred method of administration for the compositions of this invention comprises formulation of such combinations in the form of a controlled release rumen retained bolus. Oral administration of one or more controlled release boluses then provides uniform delivery of the active ingredient to the ruminant over a prolonged period of time, for instance for about three months or longer. Controlled release of the compositions of this invention is a particularly preferred method of administration to be practiced on range fed ruminants, such as range fed feeder calves and the like. Controlled release formulations comprising a composition of this invention and a carrier can be prepared by mixing a suitable combination as hereinabove described with a copolymer derived from the condensation of about 60 to about 95 parts by weight of lactic acid and about 40 to about 5 parts by weight of glycolic acid. For example, a composition of about 20 grams of monensin and about 20 grams of avoparcin can be mixed with about 80 grams of a copolymer derived from about 80 parts lactic acid and about 20 parts glycolic acid. The mixture so formed can be molded into the form of a tablet, or preferably the composition is loaded into a steel cylinder open at both ends, or some similar delivery device. Such loaded cylinder is ideally suited to oral administration to a feeder calf, and is of sufficient density to be retained in the reticulo-rumen of the animal until the time of slaughter. The formulated composition of this invention is slowly degraded such that the animal continuously receives an effective synergistic amount of feed efficiency enhancers over about a three month period. Such method of administration is ideally suited for the treatment of range fed ruminants, particularly cattle raised for human consumption. Still another method for oral administration of the composition of this invention is in the form of licks, lick tank supplements, self limiting supplements, and the like. The composition can, for example, be uniformly dispersed throughout a salt block or mineral block. The block can be placed in a feed lot, on the open range, in the feeding bin, or in similar locations for easy access by the animals. Compositions provided by this invention have been demonstrated effective in experiments designed to measure the amount of increase in feed utilization. For example, in a typical in vivo evaluation of the combination of monensin and actaplanin, feeder calves were fed a high-grain ration such as that recited above. Fifteen control animals received the feed ration with no feed efficiency enhancer additive. Another group of fifteen calves recieved the feed ration containing monensin at 30 grams per ton, while third group of fifteen animals recieved the feed ration with actaplanin at 30 grams per ton. A combination of 30 grams per ton of monensin and 30 grams per ton of actaplanin was administered as a feed additive to the ration consumed by a fourth group of fifteen test animals. The control animals receiving the feed ration having no feed efficiency enhancer additive exhibited an average daily weight gain of 1.27 pounds. The feed efficiency of such control group, calculated as the pounds of feed consumption required for one pound of animal weight gain, was 13.49. The group receiving monensin as a feed additive gained 1.42 pounds per day, a feed efficiency of 12.05, while the actaplanin group had an average daily gain of 1.38 pounds, a feed efficiency of 12.36. Surprisingly, the group receiving the combination of this invention exhibited a 1.54 pound daily gain, for a feed efficiency of only 11.08 pounds of feed for each pound of weight gain. The result of this test demonstrates that production costs of ratten- ing cattle for slaughter can be significantly reduced by utilizing a combination of feed efficiency ennancers in synergistic amounts according to this invention. An in vitro assay was designed to demonstrate the increase in propionate production effected by the combinations of this invention. Rumen fluid was obtained from steers which had surgically-installed fistula openings into the rumen. The steers were maintained cn a high-grain ration such as the one described above. A sample of rumen fluid was strained through four layers of cheese cloth and the eluate was collected in vacuum bottles. The particulate matter retained by the cheese cloth was resuspended in enough physiological buffer to return it to the original volume of the rumen fluid, and the eluate was strained again. The buffer utilized is described by Cheng et al., J. Dairy Sci., 38, 1225 (1955). The two eluates were combined in a separatory funnel and allowed to stand until any remaining particulate matter separated to the top. The clear liquid layer then was removed, diluted with an equal volume of the above-mentioned buffer, and the pH of the solution was adjusted to 7.0. Fermenter flasks were then charged with the rumen liquor thus prepared. Two fermentor flasks were used per each treatment group. The fermentor flasks were allowed to stand for four days for equilibration, and then measurements of proprionate production were made daily for six days in order to establish a control. .Measurements were made by gas chromatographic methods. The fermenter flasks were then fed 20 grams per day of a finely ground ration composed of 20 percent high concentrate ration and 80 percent alfalfa hay. The individual feed efficiency enhancers, and the composition of such enhancers provided by this invention, were added to the feed and dried thereon prior to introduction of the feed ration into the fermentor flasks. The feed rations were introduced into the flasks approximately two times each day. After the initial administration of active ingredient, two days were allowed for reequilibration, and then the volatile fatty acid (via) production in each flask was monitored by gas chromatography for five days. The results are presented in the following table. Table I Propionate Monensin PPM Actaplanin PPM Production mM/24 hours 0 0 11.4 + 2.1 SD 0 1 13.0 + 2.0 0 4 19.9 + 3.0 0.5 0 14.2 + 1.7 0.5 1 16.8 + 2.8 0.5 4 21.3 + 2.2 3 0 18.4 + 3.2 3 1 20.9 + 2.0 3 4 22.4 + 2.0 The data thus generated demonstrates that a combination of actaplanin and monensin according to this invention is synergistic in the ability to increase propionate production to levels higher than that obtainable with optimal doses of either component alone. Accordingly, the compositions provided by this invention are valuable in enhancing feed utilization efficiency in ruminants and effecting an overall economic savings to meat producers. Further embodiments provided by this invention lie in a method for increasing feed utilization efficiency and a method of promoting growth in ruminants. Such methods are accomplished by administering to a ruminant having a developed rumen function a propionate increasing amount of a combination of a glycopeptide feed efficiency enhancer and a polyether antibiotic feed efficiency enhancer as hereinabove described. The methods will be carried out by orally administering the dosage of each compound which is its respective optimal dose when utilized alone as a propionate increasing agent, i.e. a feed efficiency enhancer. Such dosage will accordingly be a propionate-increasing amount of a combination of propionate-increasing agents. A preferred method for effecting growth promotion comprises administering a propionate-increasing amount of a combination comprised of monensin and a glyco peptic selected from actaplanin and avoparcin, most preferably actaplanin. As already pointed out, the compositions of the invention can be administered orally in the form of feed additives, controlled release boluses, licks, and the like. A preferred method of oral administration of a combination of this invention is as a feed additive. Such method employs a feedstuff comprised of a combination of the invention admixed with a suitable carrier therefor. Another preferred method is in the form of a slow-release bolus. The later method is especially preferred in the treatment or range fed ruminants such as cattle and sheep. The following detailed examples are provided in an effort to illustrate specific aspects of this invention. As pointed out above, a particularly preferred composition provided by this invention comprises monensin and actaplanin. Actaplanin, like monensin, is comprised of several factors, all of which can be employed according to this invention, either individually or as a mixture of two or more factors. Example 1 Submerged aerobic cultural conditions are preferred for the production of the antibiotic A-4696 (actaplanin) factors. Relatively small amounts of the antibiotics can be produced by shake flask culture; however, for the preparation of large amounts, submerged aerobic culture in sterile tanks is preferred. The culture medium in the sterile tank can be inoculated with a mycelial fragment suspension. Accordingly, it is desirable to produce a vegetative inoculum of the organism by inoculating a relatively small quantity of culture medium with the mycelial fragments of the organism, and when a young active vegetative inoculum is obtained, to aseptically transfer it to the large tank. The medium in which the vegetative inoculum is grown can be the same as that utilized for large scale production of the antibiotic A-4696 factors, although other media can be employed. The antibiotic A-4696 factor producing Actinoplanes missouriensis strains ATCC 31680, ATCC 31681, ATCC 31682, and ATCC 31683, grow at temperatures between 200 and 400C. The largest amounts of A-4696 factors appear to be produced at a temperature of about 300C. Sterile air is blown through the culture medium in the submerged aerobic culture process. The volume of air sparged into the culture medium varies from about 0.1 to about 1.0 volume of air per minute per volume of culture medium. The most efficient growth and antibiotic production are achieved when the volume of air is at least 1/2 volume of air per minute per volume of culture medium. The rate of production of antibiotic A-4696 actors and the concentration of antibiotic activity in the culture medium can be followed during the growth period by testing samples of the fermentation broth for antibiotic activity against organisms known to be susceptible to the antibiotic. One such assay organism useful to illustrate the present invention is Bacillus subtilis. The bioassay can be carried out by the standard cup-plate methods, or by the paper disc assay on agar plates. Generally, maximum production of the antibiotic occurs within about 4 to 6 days in shake flasks or submerged aerobic culture fermentations. Antibiotic A-4696 for subsequent isolation of antibiotic A-4696 factors B1, B2, B3, Cla, C3, and E1 can be isolated from the culture medium and separated from other substances which may be present by adsorptive and extractive techniques. Adsorptive techniques are preferred because such procedures avoid the use of large volumes of solvents required in extraction processes. Since the procedures for preparing actaplanin are substantially the same when using strains ATCC 31680 (for isolation of antibiotic A-4696 factors B2 and C3), ATCC 31682 (for isolation of antibiotic A-4696 factors B1 and Cla)l and ATCC 31683 (for isolation of antibiotic A-4696 factors B3 and E1), the use of only ATCC 31682 is presented here for simplicity. Certain procedural differences relating to the production medium and the use of strain ATCC 31683 are also presented herein where appropriate. A. Shake Flask Fermentation Mycelial fragments of Actinoplanes missouriensis, illustrated here with strain ATCC 31682 for simplicity, were inoculated on a nutrient agar slant having the following composition: Ingredient Amount Cerelose 0.5% Potato dextrin 2.08 *Nutrisoy flour 1.5% Yeast extract 0.25% CaCO3 0.1% Agar 2.0t * Nutrisoy flour is obtained from Archer Daniels Midland Company, 4666 Faries Parkway, Decatur, Illinois 62526. The slant inoculated with ATCC 31682 was then incubated for 6 days at 300C. The culture does not sporulate so it is necessary to macerate the mycelial mat with a sterile pipette. The macerated mature culture was covered with sterile distilled water and scraped carefully with the pipette or a sterile rod to obtain a mycelial suspension. The suspension thus obtained was used to inoculate 100 ml. of a sterile vegetative medium having the following composition: Ingredient Amount Cerelose 0.5% Potato dextrin 2.0% Nutrisoy flour 1.5% Yeast extract 0.25% CaCO3 0.1% The inoculated vegetative medium was grown for 48 hours at 300C. on a rotary shaker operating at 250 rpm. Ten ml. of the inoculated vegetative medium was inoculated into 100 ml. of a sterile "bump" medium of the following composition. Ingredient Amount Cerelose 0.5% Yeast 0.25% Nutrisoy flour 1.5% Corn starch 2.0% CaCO3 0.1% * Sag 471 0.058 silicone antifoam agent available from Union Carbide The inoculated "bump" medium was incubated for 24 hours at 300C. with constant shaking on a rotary shaker operating at 250 rpm. Four-tenths ml. of the "bump" medium was inoculated into 100 ml. portions of a production medium of the composition shown below contained in 500 ml. Erlenmeyer flasks, and sterilized at 121"C. for 30 minutes. Ingredient Amount Cerelose 1.0% Corn starch 3.5% Sucrose 3.0% Molasses 1.5% Yeast 1.0% Proflo (Cotton seed flour) 1.0% CaCO3 0.2% K2HPO4 0.05% (NH4)2SO4 0.0258 MgSO4 7H20 0. 58 Sag 471 0.03% The production fermentation was shaken for about 96 hours at a temperature of 30"C. on a rotary shaker operating at 250 rpm. The pH at the end of the fermentation cycle was about 8.0. For production of antibiotic A-4696 factors B3 and E1, strain ATCC 31683 was used to prepare the "bump" medium according to the teaching disclosed above. Four-tenths ml. of the strain ATCC 31683 inoculated "bump" medium was inoculated into 100 ml. portions of a production medium of the composition shown below contained in 500 ml. Erlenmeyer flasks, and sterilized at 1210C, for 30 minutes. Ingredient . Amount Cerelose 1.0% Yeast 2.0% CaCO3 0.2% K2HPO3 0.05% (NH4)2SO4 0.025% Sag 471 0.03% The production fermentation was shaken for about 96 hours at a temperature of 300C. on a rotary shaker operating at 250 rpm. The pH at the end of the fermentation cycle was about 8.0. B. 40-liter tank fermentation The preparation of the inoculum proceeded through the incubation of the "bumpy medium detailed under section A, above. Twenty-five liters of a production medium as outlined above was sterilized by autoclaving at 1210C. for 30 minutes and charged into a 40 1. capacity fermentation tank. One-hundred ml. of "bump" medium was inoculated into the sterile production medium. The inoculated production medium was allowed to ferment for 4 days at 30 C. The fermentation was aerated with sterile air in an amount of about one-half volume of air per volume of culture medium per minute. The fermenting production medium was agitated with a mixer utilizing an impeller of a proper size and turning at an appropriate rpm to insure adequate mixing of air with the medium. The pH of the culture medium gradually increased from an initial level of about 6.5 to about 8.0 as the fermentation proceeded. The fermentation can be scaled up further by increasing the medium and inoculum in accordance with the ratios and procedures taught hereinabove. In this way a larger quantity of the fermentation broth can 'be conveniently produced for isolation of the antibiotic A-4696 factors. C. Isolation of Antibiotic A-4696 The fermentation broth (3800 1.) prepared according to the above procedure was filtered after the addition of 5% (wt/vol) filter aid (Celite 545). The filter cake was resuspended in deionized water (3600 1.) and the pH of the aqueous suspension was adjusted to pH 10.5 using aqueous sodium hydroxide. The suspended solids were separated by filtration and washed with water. The filtrate and the washings were combined and the resulting solution was acidified with 20% (wt/vol) aqueous sulfuric acid to pH 4.5. The acidic solution was clarified by filtration using 1% filter aid (Celite 545). The clear solution was passed through a column (1.8 x 5 ft.) containing 350 1. of Amberlite IRA-116 (Na+ form) and the column washed with deionized water (1200 1.). The IRA-116 resin was removed from the column and eluted batchwise at pH 10.5 with an aqueous solution of sodium hydroxide (total 1000 liters). The resin eluate was neutralized (pH 7) with 20% (wt/vol) aqueous sulfuric acid, then washed with three portions of deionized water (150 liters total). The water washes were neutralized and combined with the neutralized eluate. The resulting solution was concentrated and subsequently freeze dried. The preparation of the crude complex varied in color from tan to dark brown. D. Removal of Salts from Crude Antibiotic A-4696. The crude complex (1.0 kg) was slowly added with vigorous stirring to deionized water (1.5 liters). The resulting suspension was stirred for twenty minutes and was subsequently neutralized (pH 7) using a 10% aqueous ammonium hydroxide solution. The insoluble antibiotic A-4696 complex was separated by vacuum filtration, washed with deionized water, and freeze dried. The dried, desalted complex was recovered in approximately 80% yield (based on bioactivity). E. Purification of Desalted Antibiotic A-4696. The dried, desalted complex (300 g.) was suspended in deionized water (2 liters), and the pH o= the suspension was adjusted to pH 2.7 by addition of 3N aqueous hydrochloric acid. The acidified solution was centrifuged for 40 minutes at 2500 rpm. The supernatant was decanted and loaded on a column (8 x 85cm) containing 6 liters of decolorizing resin (Duolite S761). The activity was eluted with deionized water at a flow rate of 30 ml/min. The elution was monitored by thin layer chromatography. The antibiotic A-4696-containing effluent was concentrated (3 mm., 35to.) to a volume of 3 liters and freeze dried. The decolorized complex was recovered as a white-to-tan solid in approsiatel 705 yield (based on bioactiity). F. Isolation of Antibiotic A-4696 Factor B1, B2, B3, C1ar C3, and E1 Hydrochloride Salt The dried, decolorized antibiotic A-4696 complex (10 g. prepared according'to the procedure outlined above) was dissolved in 100 ml. of deionized water. The resulting aqueous solution was filtered and loaded on a chromatography column (5 x 100 cm.) containing 2 liters of polyamide (Machery & Nagel SC6). The column was eluted with deionized water and 200-300 fractions (25 ml. each) were collected. The elution was monitored by UV-activity and by thin layer chromatography. Fractions were combined according to TLC identity and freeze dried. For some of the separations it was necessary to double the column length (200 cm.) by using two of the polyamide columns in line. Additional purification was achieved by repeated chromatography. The procedures outlined in A-F above are followed using strain ATCC 31682, when isolation of antibiotic An696 factor B1 and C la is desired, using strain ATCC 31680 when isolation of A-4696 factor B2 and C3 is desired, and using strain ATCC 31683 when production of antibiotic factor A-4696 B3 and E1 is desired. While other Actinoplanes strains produce the above aforementioned factors, the strains disclosed are preferred for production of the antibiotic A-4696 factors recited herein. Example 2 An alternative method for isolating antibiotic A-4696 factors B1, B2, B3. Cla, C3, and E1 as hydrochloride salts using a single Actinoplanes missouriensis strain is as follows: The dried, decolorized antibiotic A-4696 complex (200 mg. prepared from Strain 31683 according to the teaching of Example 1, A-E above) was dissolved in about 2 ml. distilled water. The resulting aqueous solution was filtered and separated by column chromatography using reversed phase adsorbents such as, for example, Li Chroprep RP-18* as the stationary phase and aqueous acetonitrile gradients containing triethylamine phosphate as the mobile phase. Although it is understood that those skilled in the art will vary the acetonitrile concentration gradient depending upon tne composition of a particular fermentation, a preferred concentration gradient is 10-40%. The column effluent was monitored by tYV-activity and fractions containing the individual factors were collected. The acetonitrile was removed by evaporation under high vacuum and the resulting aqueous solutions were freeze dried. The freeze dried chromatography fractions were then redissolved in distilled water, adsorbed on reversed phase adsorbents such as, for example, Sep PakR C18 cartridges ** and eluted with 509 aqueous methanol. The aqueous solutions containing the individual antibiotic A-4696 factors were evaporated to dryness and the purified antibiotic A-4696 factors were then recovered as dry amorphous solids. * Available from E. Merck, Darmstadt, Germany ** Available from Waters Associates Inc., Milford, Massachusetts Example 3 Preparation of Antibiotic A-4696 Pseudo-Aglycone Dihydrochloride Salt Antibiotic A-4696 complex (2.0 g. prepared according to the teaching of Example 2) was dissolved in 50 ml. of 5% methanolic HC1 and ref fluxed for 70 minutes. The reaction mixture was evaporated to dryness at 35-400C. under reduced pressure. The residue was diluted with a small amount of water which resulted in the formation of a solid which was isolated by filtration. The solid was air dried, dissolved in a small amount of methanol and reprecipitated by the addition of acetonitrile until a granular solid formed. The desired product was then filtered, dried, and was shown by high performance liquid chromatography (HPLC) to be a single homogeneous product. The identity and structure of the desired product were confirmed by plasma desorption mass spectroscopy, proton nuclear mass resonance, and elemental analysis. Antibiotic A-4696 pseudo-aglycone dihydrochloride salt can also be prepared, in accordance with the above teaching, by hydrolysis of individual factors or mixtures of factors contained in the antibiotic A-4696 complex. Example 4 Preparation of Actaplanin factor G A nutrient agar slant having the following composition was prepared. Ingredient Amount (% by weight) Cerelose 0.5 Potato dextrin 2.0 Nutrisoy flour 1.5 Yeast extract 0.25 Calcium carbonate 0.1 Agar 2.0 The slant was inoculated with ATCC 31681 and then incubated at 300C. for about 6 days. After incubation the mycelial mat on the slant culture was covered with sterile distilled water and scraped loose with a sterile rod or loop to obtain an aqueous suspension of the mycelium. The aqueous suspension was used as the inoculum for 100 ml. of sterile vegetative medium having the same composition as the agar slant medium described above. The inoculated medium was incubated for about 48 hours at a temperature of about 300C. During incubation the vegetative medium was agitated on a rotary shaker operating at about 250 rpm. Following the growth of the vegetative medium, 10 ml. of the grown culture was withdrawn and used as the inoculum for sterile bump medium having the following composition. Ingredient Amount (t by weight) Cerelose 0.5 Yeast 0.25 Nutrisoy flour 1.5 Corn starch 2.0 Calcium carbonate 0.1 Antifoam agent (Sag 471) 0.05 The bump medium was incubated for about 24 hours at a temperature of about 300C. while agitated on a rotary shaker at 250 rpm. The grown bump medium was then used to inoculate the A-4696G sterile production medium of the following composition. Ingredient Amount (t by weight Cerelose 2.5 Yeast 2.0 Calcium carbonate 0.2 Ammonium sulfate 0.025 Dipotassium acid phosphate 0.05 Glycerine 1.5 Molasses 1.5 Corn starch 3.5 Antifoam agent (Sag 471) 0.03 The fermentation was carried out for 143 hours at a temperature of about 300C. with stirring and aeration with sterile air at a rate of about one-half volume of air per volume of culture medium per minute. DurIng the fermentation the pH of the medium increased rom an initial pH of about 6.5 to a pH of about 8.0. At the end of the fermentation (about 143 hours) the medi¯zz contained about 5,000 units of activity per ml. A portion (30 liters) of the whole fermentation broth was diluted with 30 liters of acetone and the pH adjusted to 1.8 with 6N hydrochloric acid. The acidified whole broth was filtered using a filter aid and the insolubles were washed with water on the filter. The pH of the filtrate was adjusted to 3.5 with 150 ml. of 50% sodium hydroxide and the filtrate concentrated in vacuo to a volume of 29 1. The pH was readjusted from 2.2 to 3.1 with sodium hydroxide and refiltered to remove insolubles. The filtrate containing the antibiotic was passed over a 3-inch diameter column containing 5 liters of Mitsubishi Dianion HP-20 non-functional resin (styrene-divinylbenzene resin) pretreated with methyl alcohol and washed with water. The flow rate was 250 ml/min. After adsorption of the antibiotic on the resin, the column was washed with 5 liters of water and eluted successively with 21 liters of 21% aqueous methyl alcohol, 15 liters of 50% aqueous methyl alcohol, and 15 liters of 50% aqueous acetone. Four-liter fractions of wash and eluate were collected. Fractions 8, 9 and 10 contained the majority of the antibiotic activity and was also free from most of the impurities. Fractions 8, 9 and 10 were combined and concentrated to a volume of 6 liters under vacuum. After the pH of the concentrate was adjusted to pH 6.8 with aqueous sodium hydroxide, the concentrate was poured into 60 liters of iso-propyl alcohol. A-4696G precipitated from the diluted concentrate and was filtered and dried. There were obtained 5j.2 g. of A-4696G in substantially pure form. The A-4696G obtained was further purified by HPLC. A-4696G free base is dissolved in methyl alcohol and the solution diluted with 1N hydrochloric acid. After stirring the acidified solution is diluted with acetone to precipitate the A-4696G dihydrochloride salt. Example 5 A cattle feedstuff ration containing an amount effective in increasing feed efficiency of a combination of this invention comprises the following ingredients: Percent Coarse ground corn 69.95 Groung corncobs 10.00 Soybean meal (50% protein) 8.00 Alfalfa meal 5.00 Molasses 5.00 Urea 0.60 Dicalcium phosphate 0.50 Calcium carbonate 0.50 Salt 0.30 Vitamin A and D2 premix 0.07 Vitamin E premix 0.05 Trace mineral premix 0.03 100.00 A combination of 30 grams of monensin and 30 grams or actaplanin is uniformly mixed with one ton of the above ingredients. Such feedstuff is administered orally to feeder calves at the rate of about 5 to about 30 pounds per day for effective increase in the efficiency of feed utilization. Example 6 To the feed composition of Example 5 is added a uniform mixture of 30 grams of monensin and 30 grams of avoparcin. The feedstuff is administered orally to feeder calves for effectively increasing ruminant propionate production, which is manifested as an increase in the efficiency of feed utilization. Example 7 A composition comprised of 40 grams of narasin and 25 grams of vancomycin is mixed uniformly with one ton of fodder silage. Such feedstuff is orally administered to feeder calves for effective increase in feed utilization efficiency. Example 8 Controlled release formulation for increasing rumen propionate production in range fed feeder calves. To a stirred solution of 150 ml. of dichloromethane containing 22.0 g. of a copolymer derived from about 80 percent by weight of lactic acid and about 20 percent by weight of glycolic acid, having an inherent viscosity of about 0.19, is added in one portion a uniform mixture, 12.0 g. of monensin sodium salt and 12.0 g. of actaplanin. The solution is stirred at ambient temperature for ten minutes and then the solvent is removed by evaporation under reduced pressure. The solid mass that is obtained is ground and heated to about 100"C. and packed into a steel open-ended capsule measuring 35 mm x 50 mm and weighing 98.8 g. Final weight of the packed capsule is 142.8 g. Alternatively, separate controlled release formulations of monensin and of actaplanin can be prepared and placed in two separate delivery devices or the like. The two devices can then be administered to a ruminant such that the animal receives an effective daily dose of the combination of this invention. The filled capsule is orally administered to a feeder calf via a balling gun. The calf is then permitted to graze freely on pasture. The controlled release bolus thus administered delivers a continuous and effective amount of the propionate increasing combination over about a three month period. Additional boluses can be administered as desired.

Claims: CLAIMS 1. A composition useful for enhancing the efficiency of feed utilization in ruminants comprising as a first component a propionate-increasing amount of a polyether antibiotic and a second component which is a glycopeptide antibiotic said components being present in amounts which, in combination, are synergistic to ruminant propionate increase. 2. A composition as claimed in claim 1, wherein the polyether antibiotic is selected from monensin, ionomycin1 laidlomycin, nigericin, grisorixin, dianemycin, Compound 51,532, lenoremycin, salinomycin, narasin, lonomycin, X-206, alborixin, septamycin, A-204, Compound 47,224, etheromycin, lasalocid, mutalomycin, K41, isolasalocid A, lysocellin, X-14766A, A-23187 and A-32887, and wherein the glycopeptide antibiotic is selected from actaplanin, avoparcin, A35512, A477, ristocetin, and vancomycin. 3. A composition as claimed in claim 1 or 2, wherein the polyether antibiotic employed is monensin or narasin. 4. A composition as claimed in any one of claims 1 to 3, wherein the glycopeptide is actaplanin. 5. A composition as claimed in claim 1, wherein the polyether antibiotic is monensin and the glycopeptide is actaplanin. 6. A composition as claimed in any one of claims 1 to 5 in the form of a food premix. 7. A method for increasing the efficiency of feed utilization in ruminants, which comprises orally administering thereto a composition as claimed in any one of laims 1 to 6. 8. A composition as claimed in any one of claims 1 to 6, for use in enhancing the efficiency of feed utilization in ruminants.

Inventors: POTTER, EMERSON LUCINE
Applicants: ELI LILLY AND COMPANY
Application year: 1982
Main classification: A23K1
IPC codes: A61K31, A61K38, A61K35, A61P31, A61P3, A23K1