UNIVERSITY OF CALIFORNIA COLLEGE OF AGRICULTURE AGRICULTURAL EXPERIMENT STATION BERKELEY, CALIFORNIA THE DIGESTIBILITY OF CERTAIN FRUIT BY-PRODUCTS AS DETERMINED FOR RUMINANTS PART II. DRIED PINEAPPLE PULP, DRIED LEMON PULP, AND DRIED OLIVE PULP S. W. MEAD AND H. R. GUILBERT BULLETIN 439 November, 1927 UNIVERSITY OF CALIFORNIA PRINTING OFFICE BERKELEY, CALIFORNIA 1927 Digitized by the Internet Archive in 2012 with funding from University of California, Davis Libraries http://www.archive.org/details/digestibilityofc439mead THE DIGESTIBILITY OF CERTAIN FRUIT BY-PRODUCTS AS DETERMINED FOR RUMINANTS PART II. DRIED PINEAPPLE PULP, DRIED LEMON PULP AND DRIED OLIVE PULP S. W. MEADi and H. R. GUILBERT2 INTRODUCTION Requests have come to the University for information concerning the digestibility of certain fruit by-products. During the fall of 1925 experiments were conducted on dried orange pulp and raisin pulp. The results of these experiments were reported in Bulletin 409 under the title, "The Digestibility of Certain Fruit By-Products as Deter- mined for Ruminants. Part I. Dried Orange Pulp and Raisin Pulp." 3 For purposes of comparison the digestible composition of these feeds is also given in table 11 of the present publication. In continuation of the study, Part II is a report of experiments con- ducted to determine the digestible composition of dried pineapple pulp, dried lemon pulp and dried olive pulp. The methods used in conducting these experiments were fully described in Part I. Wether sheep were used since they are easily handled and better adapted to this type of investigation than other ruminants. There is little difference in the coefficients of digestibility of the great majority of feeds as determined with sheep and with cattle. 4 The length of the preliminary feeding period was 10 days and the period during which feces were collected, and analyzed, was 15 days. 1 Assistant Animal Husbandman in the Experiment Station. 2 Junior Animal Husbandman in the Experiment Station. 3 Mead, S. W., and H. R. Guilbert. The digestibility of certain fruit by- products as determined for ruminants. Part I, Dried orange pulp and raisin pulp. California Agr. Exp. Sta. Bui. 409:1-12. 1926. * Armsby, Henry Prentiss. The nutrition of farm animals, p. 603-605. The Macmillan Company, New York. 1917. 4 UNIVERSITY OF CALIFORNIA EXPERIMENT STATION The feeds investigated were all fed in combination with alfalfa hay. A quanta sufficient for all the trials was set aside for these experiments and a digestion trial was conducted on a representative lot of this hay. The chemical determinations were made by H. W. Allinger of the Division of Chemistry. In working out the method used in these and previous trials for the preservation of feces, nitrogen determinations were made on samples of feces at the time of collection and after 15 days preserva- tion. As there were no appreciable differences in these determinations it was assumed that there would be no losses in the other nutrients. Later, it occurred to the writers that there was a possibility of a loss in some of the other constituents and especialty in ether extract and it was therefore deemed advisable to make a complete analysis of a fresh sample of feces and another analysis of the same sample after having been preserved 15 days. The sample was placed in a quart glass jar which had previously been rinsed with a 10 per cent alcoholic solution of thymol. To this was added 5 grams of powdered thymol and the whole thoroughly mixed. A portion of this sample was imme- diately analyzed and the remainder carefully sealed in the jar and placed in a refrigerator, the temperature of which was maintained at between 30-40 degrees Fahrenheit. Since the collection period in the digestion trials lasted 15 days, the longest possible period of storage would be only 14 days, as the samples are analyzed immediately after the termination of the collection period. Hence the check sample was again analyzed at the end of 14 days. That there was no signifi- cant change in the composition of the feces is shown in table 1. The results of the two analyses are almost identical. The slight difference might easily be expected of two separate samples of feces taken from the same source at the same time. TABLE 1 Preservation of Feces Feces Moisture Crude protein Nitrogen-free extract Ether extract Crude fiber Total ash Fresh 61.44 61.70 5.00 4.99 17.36 17.26 1.52 1.43 11.66 11.60 3.02 Preserved 14 days 3.02 BUL. 439] DIGESTIBILITY OF CERTAIN FRUIT BY-PRODUCTS RESULTS OF THE DIGESTION TRIAL WITH DRIED PINEAPPLE PULP Pineapple pulp, a by-product of the canneries, consists of the outer skin, trimmings, core and ends of the pineapple, from which the juice has been extracted. At the present time the production in the Hawaiian Islands amounts to 5000 tons of dried pulp annually, about one-half of which is exported to California, for the feeding of dairy cows in the Los Angeles district. As several pineapple canneries are not yet drying pulp the amount available may be increased somewhat but the supply will probably never be large. Pineapple pulp has been used for sometime with satisfactory results as a feed for dairy cattle and swine at the University of Hawaii, 5 where comparative feeding trials are now r being conducted with it. However, no data have been available concerning its digestibility. The nutritive value of any feed is dependent largely upon its digestible composition. Data reported in table 11 show that the dried pineapple pulp used in this trial contained 59.9 per cent total digestible nutrients as compared to 71.6 per cent in dried beet pulp, a feed of somewhat similar physical characteristics. It is interesting to note that a sample of the particular pulp used in this trial was analyzed five months previously and found to contain 11.36 per cent moisture. At the time of the trial the moisture content was 16.40 per cent. A variation as great or even greater than this would be expected of any similar feed under varying climatic conditions such as are common to California. The average dry matter content for dried beet pulp as given in table 11 is 91.8. Calculating dried pineapple pulp on the same dry matter basis 100 pounds should contain approximately 66 pounds of digestible nutrients. The digestible protein content of pine- apple pulp is, however, extremely low, because of the small amount of total crude protein and its low coefficient of digestibility. The small amount of ether extract present in the feed may explain the negative coefficient of digestibility of that nutrient. In many parts of California dairy cattle are fed largely on alfalfa. Under such conditions dried pineapple pulp and other feeds of a carbonaceous nature, when they can be purchased at a reasonable price, may be used with advantage in balancing the ration. s Henke, L. A. Ninth annual report of the agricultural department of the University of Hawaii for the fiscal year July 1, 1925, to June 30, 1926. Univ. Hawaii Quart. Bui. 6:14-16. 1926. (i Fraps, G. S. Energy-production coefficients of American feeding stuffs. Texas Agr. Exp. Sta. Bui. 329:6-13. 1925. UNIVERSITY OF CALIFORNIA EXPERIMENT STATION TABLE 2 Total Feed Consumed and Total Feces Collected Sheep number Alfalfa hay Pineapple pulp Feces Grams Grams Grams 137 4500 6375 6955 135 4500 6375 7339 136 4125 6000 6799 138 5100 • 7500 9141 TABLE 3 Chemical Analyses of Feces and Feeds Sheep number Dry matter Crude protein Nitrogen-free extract Ether extract Crude fiber Feces: 137 Per cent 38.65 37.88 36.72 35.52 85.38 83.60 Per cent 5.10 4.94 4.74 4.77 15.47 3.81 Per cent 16.56 16.19 15.69 14.95 35.72 61.94 Per cent 1.45 1.43 1.42 1.36 1.66 0.71 Per cent 12.37 135 136 138 Feeds: Alfalfa hay Dried pineapple pulp. ... 12.28 11.85 11.54 24.14 13.88 TABLE 4 Coefficients of Digestibility of Dried Pineapple Pulp and Alfalfa Hay Sheep number Dry matter Crude protein Nitrogen-free extract Ether extract Crude fiber Per cent Per cent Per cent Per cent Per cent 137 75.566 23.011 80.070 0.583 72.775 135. 73.842 19.783 79.148 -8.475 68.154 136 75.554 26.273 80.294 -6.497 71.438 138 73.266 13.926 79.482 -14.593 66.105 Average 74.557 20.748 79.748 Negative 69.618 Alfalfa hay 63.928 75.909 77.304 25.236 42.977 To test the palatability of plain dried pineapple pulp, it was fed to dairy cows. During the first two weeks of the test it was necessary to add 1 pound of wheat bran to every 3 pounds of the pulp in order to induce cows to consume any considerable amount of it. At the BUL. 439] DIGESTIBILITY OF CERTAIN FRUIT BY-PRODUCTS 7 end of this period, each cow consumed 6 pounds daily of the dry pulp. In the digestion trial the pulp was readily eaten by sheep. Dried pineapple pulp as sold on the market contains a small amount of cane molasses which greatly increases its palatability. The data from the digestion trial with pineapple pulp fed in combination with alfalfa hay are given in tables 2, 3 and 4. RESULTS OF THE DIGESTION TRIAL WITH DRIED LEMON PULP Lemon pulp is a by-product in the manufacture of citric acid and pectin and consists of the rind, pulp and seeds which are the residue after extraction. Calculated on the dried basis, between 3000 and 6000 tons are produced annually. At the present time less than a fourth of this amount results from the manufacture of pectin. It seemed advisable, therefore, to determine the digestibility of the citric acid pulp only. Dried lemon pulp compares favorably with dried orange pulp in total digestible nutrients though it contains 3 per cent less digestible protein. In both digestible protein and total digestible nutrients it is equal to dried beet pulp as shown in table 11. On account of its bitter taste, dried lemon pulp is not relished by livestock. Both dried lemon pulp and dried orange pulp must be mixed with more palatable feeds to induce stock to consume any appreciable amount. In a palatability test with dried lemon pulp, dairy cows were finally induced to consume 2 pounds per day when the lemon pulp was mixed with an equal weight of a concentrate mixture consisting of 4 parts barley, 2 parts rice bran and 1 part cottonseed meal, plus salt. The data from the digestion trial with lemon pulp fed in combina- tion with alfalfa hay are given in tables 5, 6 and 7. TABLE 5 Total Feed Consumed and Feces Collected Sheep number Alfalfa hay- Dried lemon pulp Feces Grams Grams Grams 717 8775 4500 10174.5 600 10050 5175 12245.5 736 8775 4500 9259.0 686 7800 3975 8046 5 UNIVERSITY OF CALIFORNIA EXPERIMENT STATION TABLE 6 Chemical Analyses of Feces and Feeds Sheep number Dry matter Crude protein Nitrogen-free extract Ether extract Crude fiber Feces: 717 600 736 686 Feed: Alfalfa hay Per cent 34.23 33.76 37.95 39.19 87.28 92.90 Per cent 4.91 4.85 4.89 5.31 15.76 6.39 Per cent 9.70 9.42 10.66 10.22 37.26 65.24 Per cent 1.30 1.34 1.46 1.70 1.54 1.23 Per cent 14.04 13.48 15.65 15.92 23.43 Dried lemon pulp 15.00 TABLE 7 Coefficients of Digestibility of Dried Lemon Pulp and Alfalfa Hay Sheep number Dry matter Crude protein Nitrogen-free extract Ether extract Crude fiber Per cent Per cent Per cent Per cent Per cent 717 82.776 42.132 91.659 43.568 62.056 600 79.824 35.789 91.006 23.999 60.326 736 82.033 58.407 91.656 38.305 59.014 686 81.106 48.377 93.724 3.904 59.935 Average 81.484 46.176 92.011 27.444 60.332 Alfalfa hay 63.928 75.909 77.304 25.236 42.977 RESULTS OF THE DIGESTION TRIAL WITH DRIED OLIVE PULP Olive pulp is a by-product in the manufacture of olive oil. It con- sists of the whole olive minus most of the oil. At present it is being utilized largely as fuel in the plants manufacturing olive oil. The estimated production is 2000 to 4500 tons annually. Requests were made for information concerning its possible value as a feed for live- stock. The olive pulp was supplied by P. F. Nichols of the Division of Viticulture and Fruit Products. It had been dehydrated and ground to a fine meal. As shown in table 10 the pulp used was found to be practically valueless as a feed for livestock, only 19 per cent of the dry matter being digested. Since a large amount of the digestible matter was oil which has a value of 2.25 times that of an equal weight BUL. 439] DIGESTIBILITY OF CERTAIN FRUIT BY-PRODUCTS 9 of carbohydrates, 100 pounds of the material contain 36.6 pounds of total digestible nutrients ; thus it has, as shown in table 11, a feeding value similar to that of wheat straw. Dried olive pulp contains approximately 60 per cent pit, the shell of which is largely crude fiber of an indigestible nature. A great quantity of the ground pit was found in an apparently unchanged condition in the feces. As shown in table 9 the dried olive pulp had 36 per cent fiber or 12 per cent more than was contained in the alfalfa hay used in the experiment. This large amount of crude fiber apparently interfered with the digestion of not only the olive pulp but also of the alfalfa hay which was fed with the pulp, 7 ' 8 the digestion coefficients of which had pre- viously been determined by a trial with alfalfa hay alone. In deter- mining the value of dried olive pulp it was necessary to subtract from the amount of total feed digested the calculated amount of alfalfa digested allowing full value for alfalfa hay. This resulted in negative values for crude protein and crude fiber in the olive pulp as shown in table 10. If it were practical to feed dried olive pulp alone and hence determine its digestibility directly the calculated coefficient might have been slightly higher. However, when fed in combination with a roughage, which would be the usual procedure, the figures given in table 11 probably express very nearly the true value of this material. Since the olive pulp used in this trial was found to have a very low nutritive value the question arose as to its value with the pits removed. A sample of pulp with the pits removed was analyzed and found to have the following composition: Dry matter 95.11 per cent, crude protein 13.99 per cent, nitrogen-free extract 31.04 per cent, ether extract 27.39 per cent, crude fiber 19.27 per cent and ash 3.43 per cent. 9 This material contains considerably less fiber than the original pulp and it is reasonable to believe that the digestibility of all the nutrients would therefore be increased. In view of the large amount of highly , digestible ether extract and the expected increase in digestibility of the other nutrients, the pit free pulp should have approximately double the value of that used in the digestion trial. 7 Mumford, H. W., II. S. Gridley, L. D. Hall, and A. D. Emmet. A study of the digestibility of rations for steers. Illinois Agr. Exp. Sta. Bui. 172:246-255. 1914. s Armsby, Henry Prentiss. The nutrition of farm animals, pp. 613-623. The Macmillan Company, New York. 1017. 9 These data were supplied by the Division of Viticulture and Fruit Products at Berkeley. 10 UNIVERSITY OF CALIFORNIA EXPERIMENT STATION Unless the pulp, free from pits, can be produced commercially and in sufficiently large quantities to justify more complete data, no further work will be conducted. The data from the digestion trial with dried olive pulp fed in combination with alfalfa hay are given in tables 8, 9 and 10. TABLE 8 Total Feed Consumed and Feces Collected Sheep number Alfalfa hay Olive pulp Feces Grams Grams Grams 726 8775 4500 13861 600 10050 5175 14217 736 :. 8775 4500 12201 717 8775 4500 12389 686 7800 3975 10376 TABLE 9 Chemical Analyses of Feces and Feeds Sheep number Dry matter Crude protein Nitrogen-free extract Ether extract Crude fiber Feces: Per cent Per cent Per cent Per cent Per cent 726 44.86 4.57 3.45 1.59 22 AS 600 48.52 4.90 14.80 1.66 24.03 736 50.61 5.18 15.51 1.66 24.84 717 48.94 4.96 15.07 1.63 24.18 686 51.49 5.15 15.67 1.70 25.37 Feeds: Alfalfa hay 86.84 15.24 36.50 1.64 24.14 Dried olive pulp 92.02 5.91 31.54 15.63 36.45 TABLE 10 Coefficients of Digestibility of Dried Olive Pulp and Alfalfa Hay Sheep number Dry matter Crude protein Nitrogen-free extract Ether extract Crude fiber Per cent Per cent Per cent Per cent Per cent 726 16.219 -17.042 19.863 83.963 -16.326 600 21.253 - 7.130 22.094 86.057 - 7.774 736 17.260 -16.502 17.885 86.501 -11.130 717 19.959 - 9.916 19.671 86.586 - 8.992 686 20.737 - 5.562 21.851 87.002 - 7.578 Average 19.085 Negative 20.272 86.021 Negative Alfalfa hay 63.928 75.909 77.304 25.236 42.977 BUL. 439] DIGESTIBILITY OF CERTAIN FRUIT BY-PRODUCTS 11 TABLE 11 Digestible Nutrients Contained in Various Common Feeds Compared with Dried Pineapple Pulp, Dried Lemon Pulp and Dried Olive Pulp Total dry matter in 100 pounds Digestible nutrients in 100 pounds Feeding stuff Crude protein Carbo- hydrates Fat Total* Common barley f Dried orange pulp J... Pounds 90.7 87.5 92.9 91.8 83.6 91.4 91.6 92.0 88.7 Pounds 9.0 6.0 3.0 4.6 0.8 10.6 0.7 0.0 2.3 Pounds 66.8 70.4 69.1 65.2 59.1 39.0 35.1 6.4 27.3 Pounds 1.6 0.8 0.3 0.8 0.0 0.9 0.5 13.4 9.5 Pounds 79.4 78.2 Dried lemon pulp 72.8 Dried beet pulpj Dried pineapple pulp Alfalfa hayt, all analyses.. Wheat strawf Dried olive pulp. . .< Raisin pulpj . y . 71.6 59.9 51.6 36.9 36.6 51.0 * Total includes fat times the factor 2.25. tHenry, W. A., and F. B. Morrison Feeds and feedings. Ed. The Henry-Morrison Company, Madison, Wis. t Citation in footnote, page 1. Table III, App. Eighteenth 192J