FORESTOMACH MOTILITY IN ADULT SHEEP WHEN RETICULAR GROOVE CLOSURE IS PROVOKED BY COPPER SULPHATE SOLUTION

Transcription

1 FORESTOMACH MOTILITY IN ADULT SHEEP WHEN RETICULAR GROOVE CLOSURE IS PROVOKED BY COPPER SULPHATE SOLUTION Ch. Tsiamitas, P. Brikas To cite this version: Ch. Tsiamitas, P. Brikas. FORESTOMACH MOTILITY IN ADULT SHEEP WHEN RETICU- LAR GROOVE CLOSURE IS PROVOKED BY COPPER SULPHATE SOLUTION. Annales de Recherches Vétérinaires, INRA Editions, 1981, 12 (2), pp <hal > HAL Id: hal Submitted on 1 Jan 1981 HAL is a multi-disciplinary open access archive for the deposit and dissemination of scientific research documents, whether they are published or not. The documents may come from teaching and research institutions in France or abroad, or from public or private research centers. Larchive ouverte pluridisciplinaire HAL, est destinée au dépôt et à la diffusion de documents scientifiques de niveau recherche, publiés ou non, émanant des établissements denseignement et de recherche français ou étrangers, des laboratoires publics ou privés.

2 FORESTOMACH MOTILITY IN ADULT SHEEP WHEN RETICULAR GROOVE CLOSURE IS PROVOKED BY COPPER SULPHATE SOLUTION Ch. TSIAMITAS P. BRIKAS Laboratory of Physiology, Veterinary Faculty, Aristotelian University of Thessaloniki, Greece Résumé MOTRICITÉ DES PRÉ-ESTOMACS CHEZ LE MOUTON LORS DU DÉCLENCHEMENT DE LA FERMETURE DE LA GOUTTIÈRE OESOPHAGIENNE - La motricité des pré-estomacs a été étudiée par enregistrement de lactivité électrique de la musculature pariétale chez sept brebis adultes lors du déclenchement de la fermeture de la gouttière oesophagienne par 10 ml dune solution de 10% de sulfate de cuivre. La motricité du rumen et du feuillet a disparu avec ladministration du stimulant pendant quune activité musculaire du réseau persistait mais se manifestait par des contractions monophasiques dune fréquence plus élevée et dune activité électrique réduite par rapport à celles enregistrées avant la stimulation ; parmi ces contractions des petites décharges très fréquentes ont apparu à lélectroréticulogramme. Lactivité cyclique des pré-estomacs a réapparu 3-5 min plus tard pour redevenir graduellement normale. Limportance fonctionnelle des résultats obtenus est discutée. The motility of the young ruminant forestomach during sucking has been investigated among others by Schalk and Amadon (1928) and Kay and Ruckebusch (1971 a, b). The reflex closure of the reticular groove provoked in adult sheep for the purpose of dosing them directly into the abomasum, gives rise to a similar question which could be of clinical importance : what is the smooth muscle forestomach activity in these animals when the above reflex is elicited? Mbnnig and Quin (1935) showed that a 10% copper sulphate solution is the most potent agent to bring about reflex closure of the reticular groove by stimulating buccopharyngeal receptors in adult sheep. Watson and Jarrett (1944) confirmed this action of copper sulphate. Recently (1977), Smith et al. found that zinc also stimulates the reticular groove reflex in adult sheep and that this effect depends on the concentration of the zinc solution. In the present work we used a 10% copper sulphate solution to produce the reticular groove closure in adult sheep and we studied the forestomach motility. For this purpose continuous electromyographic records from conscious undisturbed animals were obtained.

3 Materials and Methods Seven ewes (A to G), 2 to 5 years old, weighing kg, were used. They were given hay and water ad libitum. In each animal six pairs of electrodes were chronically implanted as described by Ruckebusch ( One pair was placed on the diaphragmatic reticular wall ; three pairs were fixed on the rumen, one on the dorsal, one on the ventral and one on the caudo-ventral sac ; the remaining two pairs were implanted on the visceral (left) and parietal (right) wall of the omasum midway between the greater and lesser curvature, 5 cm beyond the reticuloomasal orifice. Recordings of the electrical activity of the reticulo-rumen and omasum started one week after the implantation and each animal was used day by day for three weeks, with its electrodes connected to an EEG machine (Physiograph Six-B, Narco Bio-Systems). After two hours of control recording the sheep was drenched with 10 ml of 10% copper sulphate solution (C US0 4-5H 20, A.R., B.D.H.) and the recording was continued for about 4 h. All animals used were previously tested for their ability to close the reticular groove when drenched with copper sulphate solution. For these tests a process based on that of Riek (1954) was followed : each animal was given orally 100 ml of 20% glucose solution and the blood glucose concentration was determined (see fig. 1A referring to three of the seven animals) in samples taken at intervals of 30 min for 4 h. This process was repeated two days later, the administration of the glucose solution immediately following drenching with 10 ml of 10% copper sulphate solution. From the results obtained (fig. 1 B) it was concluded that all the sheep tested reacted positively to this stimulant. Results The electromyographic records from the forestomach taken when the sheep were drenched with copper sulphate solution show the following : Rumen and omasum motility ceased with the administration of the buccopharyngeal receptor stimulant (fig. 2Bl, 3-5) ; this pause lasts for 3 to 5 min and then the ruminal motility reappears, with contractions decreased in strength but increased in frequency (fig. 2C 3-5). Regarding the omasum, its inhibition is followed by an accentuated motility which gradually becomes normal as can be seen in fiq. 2Cl.

4 Concerning the reticulum, the electromyograms show a differentiation of its motility : while the rumen and omasum are completely inactive, very frequent small discharges appear in the electromyogram from the reticulum but the electrical grouped discharges indicating reticular contractions are also present. These contractions, however, have lost their biphasic character and have become more frequent and weaker than before administration of the drench (fig. 31. The reticular motility returns gradually to normal at almost the same time as that of the rumen and omasum (fig. 2C). The purpose of this work was not to study the effects of the absorbed copper sulphate on forestomach motility, but it is worth mentioning that rumino-reticular motility in all our animals and in most experiments showed, 30 to 45 min after drenching with copper sulphate solution, a disturbance featured by weakened contractions of the forestomach and decreased frequency of the ruminoreticular cycles. The normal cycles usually reappeared 1 to 2 h later. To discuss this subject, however, we need further investigation. Discussion Schalk and Amadon (1928) noticed that the rhythmic contractions of the rumino-reticulum ceased while the animal was sucking milk. About forty years later Kay and Ruckebusch (1971 a, b), working on young ruminants, found that the contractions of the forestomach were inhibited whenever the animals sucked milk or water and that the reticulum contractions either ceased altogether or became more frequent but weaker. Our results with adult sheep drenched with copper sulphate solution are in agreement with the above observations with the exception of those concerning the reticulum, the

5 contractions of which never ceased, as noticed the above investigators. Regarding the inhibition of rumen and omasum motility that occurs with reflex reticular groove closure establishment, either when the young ruminant is sucking or when the adult sheep is drenched with copper sulphate solution, we consider this to be of functional significance since any activity of the rumen during reticular groove closure would interfere with the reticular groove muscle contraction ; on the other hand, any contraction of the omasum during the above closure would make difficult the relaxation of the reticulo-omasal orifice observed by Titchen and Newhook (1975) during drinking and the consequent passage of the swallowed fluid through the omasal groove towards the abomasum (Bueno, 1975). As far as the reticulum is concerned some muscular activity was always present in our recordings ; this is in contrast to those cases of Kay and Ruckebusch (1971 b) that the reticulum contractions ceased altogether. We point out, however, that this activity was disorganized and was manifested by monophasic, more frequent and weaker contractions than before drenching. Furthermore, between these contractions very frequent small discharges were recorded in the electromyogram from the reticulum, indicating a possible increase in tonus. This muscular activity of the reticulum may perhaps be necessary to sustain the continuously and effectively contracted lips of the reticular groove. On the other hand, we suggest that the relaxation of the reticulum in young ruminants when they suck would not reduce

6 their undoubted ability to close the reticular groove. Thus, it is suggested that forestomach motility during reticular groove closure is almost similar in both young and adult ruminants. Accepted for publication, April 23rd, Acknowledgements We are grateful to Dr. A. Agiannidis for blood glucose measurements. Summary Forestomach motility in adult sheep when reflex reticular groove closure is provoked by 10 ml of 10% copper sulphate solution was studied electromyographically. Rumen and omasum motility disappeared with the administration of the stimulant, while some muscular activity of the reticulum was always present but was manifested by monophasic, more frequent and weaker contractions than before stimulation ; between these contractions very frequent small discharges appeared in the electromyogram from the reticulum. Cyclic activity of the forestomach reappeared 3 to 5 min later and returned gradually to normal. The functional significance of these findings is discussed. References BUENO L., Les fonctions motrices et digestives du feuillet. These Doctorat 6s Sciences, Toulouse. KAY R.N.B., RUCKEBUSCH Y., 1971a. The effects of sucking on the motility of the forestomach in young ruminants. J. Physiol., 214, 34P. KAY R.N.B., RUCKEBUSCH Y., 1971b. Movements of the stomach compartments of a young bull during sucking. Br. J. Nutr., 26, MONNIG H.O., QUIN J.1., Studies on the alimentary tract of the merino sheep in South Africa. 11. Investigations on the Physiology of Deglutition. Onderstepoort J. Vet. Sc. Anim. Ind., 5, RIEK R.F., The influence of sodium salts on the closure of the oesophageal groove in calves. Aust. Vet. J., 30, RUCKEBUSCH Y., The electrical activity of the digestive tract of the sheep as an indication of the mechanical events in various regions. J. Physiol., 210, SCHALK A.F., AMADON R.S., The physiology of the ruminant stomach. North Dakota Agric. Exp. Sta. Bull., 216, SMITH B.L., REYNOLDS G.W., EMBLING P.P., Zinc solutions and closure of the reticular groove in sheep. N. Z. J. Exper. Agric., 5, TITCHEN D.A., NEWHOOK J.C., Physiological aspects of sucking and the passage of milk through the ruminant stomach. ln : I.W. MCDONALD, A.C.I. WARNER, Digesticn and Metabolism in the Ruminant, p , University of New England, Armidale. WATSON R.H., JARRETT I.G., Studies on deglutition in sheep 2. Observations on the influence of copper salts on the course taken by liquids into the stomach of the sheep. Bull. Counc. Sci. lnd. Res., Melbourne, n 180,