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Regulation of pH in the Intestine of the Laying Fowl1
REGULATION OF pH IN THE INTESTINE OF THE LAYING FOWL1
Along with the evaluation of the electrochemical potential of various cations, we have recently measured the in vivo pH along the intestinal tract of the laying hen (Hurwitz et al., 1968). The intra-luminal pH was found to increase with the distance from the pylorus, in agreement with measurements made on various animals (Tyler, 1946; Smith, 1962; Alexander, 1965). Thus, it was of interest to see if the intestinal pH was physiologically regulated or whether it was merely the sum of the acid base balance of the intestinal digesta, as they move along the intestine. Wilson and Kazyak (1957) introduced bicarbonate buffer into rat intestinal sacs in situ, and found that after 30 minutes the pH increased in the ileum and decreased in the jejunum. Waldron-Edward et al. (1966) introduced several buffers into various intestinal segments of rat intestine in situ. With saline solution of pH 5.55 typical pH's of the various intestinal segments were observed after 30 minutes of incubation. In these experiments, however, ligated sacs were incubated and no attempt was made to evaluate the time course of the changes in the intestinal pH. In order to measure the regulation capacity of the pH in situ, perfusions of laying hen-intestine with saline solutions were carried out. After an abdominal incision in Nembutal-anesthetized birds, 25 cm. of jejunum and ileum were exposed and rinsed well with physiological saline. They were 1 Contribution from the Volcani Institute of Agriculture 1967 series No. 1234-E supported by the United States Department of Agriculture under P.L. 480.
FIG. 1. The intestinal pH during infusion with saline solution with variable pH's. Upper portion, ileum; lower portion, jejunum; and US, © are the in vivo pH's for the ileum and jejunum, respectively, as previously determined (Hurwitz et al., 1968).
then connected to peristaltic pump through a system of plastic tubing, and 25 ml. of the test solution were recirculated through each segment. Samples were taken at 10 minute intervals and their pH measured with a Radiometer pH-meter. Three saline solutions (0.9% NaCl) were used, having the following pH's: 4.3, 6.3, and 8.9; pH adjustments were made by addition of either HC1 or NaOH. Those
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Downloaded from http://ps.oxfordjournals.org/ at Ernst Mayr Library of the Museum Comp Zoology, Harvard University on July 2, 2015
S. HURWITZ AND A. BAR Division of Poultry Science, The Volcani Institute of Agricultural Research, Rehovot, Israel (Received for publication February 20, 1968)
1030
RESEARCH NOTES REFERENCES Alexander, R. A., 1965. The concentration of electrolytes in the alimentary tract of the rabbit, guinea pig, dog and cat. Res. Vet. Sci. 6: 238-244. Dixon, W. J., and F. J. Massey, Jr., 1957. Introduction of Statistical Analysis. McGraw-Hill Book Co., New York, p. 171. Hurwitz, S., A. Bar and T. W. Clarkson, 1968, Unpublished data. Smith, R. H., 1962 Net exchange of certain inorganic ions and water in the alimentary tract of the milk-fed calf. Biochem. J. 83: 151-163. Tyler, C , 1946. Studies on the absorption and excretion of certain minerals by poultry II. Changes in the composition of food material as it moves along the alimentary tract of the hen. J. Agr. Sci. 36:275-282. Waldron-Edward, D., T. M. Paul and S. C. Skoryna, 1966. Effect of the counter ion and pH on the intestinal absorption of Ca and Sr. Proc. Soc. Exp. Biol. Med. 123: 532-538. Wilson, T. H., and L. Kazyak, 1957. Acid-base changes across the wall of hampster and rat intestine. Biochem. Biophys. Acta, 24: 124-132.
INCIDENCE OF PARTHENOGENESIS IN EGGS OF VARIOUS STRAINS AND VARIETIES OF DOMESTIC TURKEYS, MELEAGRIS GALLOPAVO MARLOW W. OLSEN AND STANLEY J. MARSDEN United States Department of Agriculture1 (Received for publication March 4, 1968)
Since 1953 considerable work at this Station has been devoted to the study of parthenogenetic development in Beltsville Small White (BSW) turkey eggs. Most of the work dealt with the incidence of parthenogenesis as influenced by selection and by environmental factors. It also was of interest to determine how widespread this form of development was, and to what extent it occurred, in eggs of other varieties and strains of domestic turkeys. 1
Animal Husbandry Research Division, ARS, Beltsville, Md. 20705.
These tests involved a total of 3,048 unfertilized eggs from 116 young turkeys representing 9 different varieties, strains, and variety crosses. Three of the groups were secured from commercial sources, the remainder were from State experiment stations. None of the hens involved had been selected for a high incidence of parthenogenetic development. In conducting the parthenogenetic tests, the same general procedures were followed as those outlined by Olsen and Marsden (1953), i.e., eggs from virgin hens were incubated at 37.6°C. (99|°F.) for 7-11 days.
Downloaded from http://ps.oxfordjournals.org/ at Ernst Mayr Library of the Museum Comp Zoology, Harvard University on July 2, 2015
solutions were alternated in three hens according to a Latin Square design (Dixon andMassey, 1957). The results presented in Figure 1 demonstrate a remarkable pH adjustment by the intestine. In the ileum, after only 10-20 minutes, the pH of the three saline solutions was almost identical. The pH then gradually rose during perfusion, to reach a typical pH as measured by us previously in the intact hen. An "overshot" of pH can be observed at 10 minutes in the ileum perfused with the basic pH (8.9) solution. The regulation of the pH in the jejunum was not as efficient as in the ileum. The mechanism of the intra-luminal pH regulation is not very clear. Transport of bicarbonate was implicated as a means of regulating the pH (Wilson and Kazyak, 19S7). It is very possible that acid production by the intestinal mucosa may also play an important role.
Along with the evaluation of the electrochemical potential of various cations, we have recently measured the in vivo pH along the intestinal tract of the laying hen (Hurwitz et al., 1968). The intra-luminal pH was found to increase with the distance from the pylorus, in agreement with measurements made on various animals (Tyler, 1946; Smith, 1962; Alexander, 1965). Thus, it was of interest to see if the intestinal pH was physiologically regulated or whether it was merely the sum of the acid base balance of the intestinal digesta, as they move along the intestine. Wilson and Kazyak (1957) introduced bicarbonate buffer into rat intestinal sacs in situ, and found that after 30 minutes the pH increased in the ileum and decreased in the jejunum. Waldron-Edward et al. (1966) introduced several buffers into various intestinal segments of rat intestine in situ. With saline solution of pH 5.55 typical pH's of the various intestinal segments were observed after 30 minutes of incubation. In these experiments, however, ligated sacs were incubated and no attempt was made to evaluate the time course of the changes in the intestinal pH. In order to measure the regulation capacity of the pH in situ, perfusions of laying hen-intestine with saline solutions were carried out. After an abdominal incision in Nembutal-anesthetized birds, 25 cm. of jejunum and ileum were exposed and rinsed well with physiological saline. They were 1 Contribution from the Volcani Institute of Agriculture 1967 series No. 1234-E supported by the United States Department of Agriculture under P.L. 480.
FIG. 1. The intestinal pH during infusion with saline solution with variable pH's. Upper portion, ileum; lower portion, jejunum; and US, © are the in vivo pH's for the ileum and jejunum, respectively, as previously determined (Hurwitz et al., 1968).
then connected to peristaltic pump through a system of plastic tubing, and 25 ml. of the test solution were recirculated through each segment. Samples were taken at 10 minute intervals and their pH measured with a Radiometer pH-meter. Three saline solutions (0.9% NaCl) were used, having the following pH's: 4.3, 6.3, and 8.9; pH adjustments were made by addition of either HC1 or NaOH. Those
1029
Downloaded from http://ps.oxfordjournals.org/ at Ernst Mayr Library of the Museum Comp Zoology, Harvard University on July 2, 2015
S. HURWITZ AND A. BAR Division of Poultry Science, The Volcani Institute of Agricultural Research, Rehovot, Israel (Received for publication February 20, 1968)
1030
RESEARCH NOTES REFERENCES Alexander, R. A., 1965. The concentration of electrolytes in the alimentary tract of the rabbit, guinea pig, dog and cat. Res. Vet. Sci. 6: 238-244. Dixon, W. J., and F. J. Massey, Jr., 1957. Introduction of Statistical Analysis. McGraw-Hill Book Co., New York, p. 171. Hurwitz, S., A. Bar and T. W. Clarkson, 1968, Unpublished data. Smith, R. H., 1962 Net exchange of certain inorganic ions and water in the alimentary tract of the milk-fed calf. Biochem. J. 83: 151-163. Tyler, C , 1946. Studies on the absorption and excretion of certain minerals by poultry II. Changes in the composition of food material as it moves along the alimentary tract of the hen. J. Agr. Sci. 36:275-282. Waldron-Edward, D., T. M. Paul and S. C. Skoryna, 1966. Effect of the counter ion and pH on the intestinal absorption of Ca and Sr. Proc. Soc. Exp. Biol. Med. 123: 532-538. Wilson, T. H., and L. Kazyak, 1957. Acid-base changes across the wall of hampster and rat intestine. Biochem. Biophys. Acta, 24: 124-132.
INCIDENCE OF PARTHENOGENESIS IN EGGS OF VARIOUS STRAINS AND VARIETIES OF DOMESTIC TURKEYS, MELEAGRIS GALLOPAVO MARLOW W. OLSEN AND STANLEY J. MARSDEN United States Department of Agriculture1 (Received for publication March 4, 1968)
Since 1953 considerable work at this Station has been devoted to the study of parthenogenetic development in Beltsville Small White (BSW) turkey eggs. Most of the work dealt with the incidence of parthenogenesis as influenced by selection and by environmental factors. It also was of interest to determine how widespread this form of development was, and to what extent it occurred, in eggs of other varieties and strains of domestic turkeys. 1
Animal Husbandry Research Division, ARS, Beltsville, Md. 20705.
These tests involved a total of 3,048 unfertilized eggs from 116 young turkeys representing 9 different varieties, strains, and variety crosses. Three of the groups were secured from commercial sources, the remainder were from State experiment stations. None of the hens involved had been selected for a high incidence of parthenogenetic development. In conducting the parthenogenetic tests, the same general procedures were followed as those outlined by Olsen and Marsden (1953), i.e., eggs from virgin hens were incubated at 37.6°C. (99|°F.) for 7-11 days.
Downloaded from http://ps.oxfordjournals.org/ at Ernst Mayr Library of the Museum Comp Zoology, Harvard University on July 2, 2015
solutions were alternated in three hens according to a Latin Square design (Dixon andMassey, 1957). The results presented in Figure 1 demonstrate a remarkable pH adjustment by the intestine. In the ileum, after only 10-20 minutes, the pH of the three saline solutions was almost identical. The pH then gradually rose during perfusion, to reach a typical pH as measured by us previously in the intact hen. An "overshot" of pH can be observed at 10 minutes in the ileum perfused with the basic pH (8.9) solution. The regulation of the pH in the jejunum was not as efficient as in the ileum. The mechanism of the intra-luminal pH regulation is not very clear. Transport of bicarbonate was implicated as a means of regulating the pH (Wilson and Kazyak, 19S7). It is very possible that acid production by the intestinal mucosa may also play an important role.