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Plasma and Faecal Osmolality, Water Kinetics and Body Fluid Compartments in Neonatal Calves with Diarrhoea
13r. vet.
J.
(197 1), 127, 37
PLASMA AND FAECAL OSMOLALITY, WATER KINETICS AND BODY FLUID COMPARTMENTS IN NEONATAL CALVES WITH DIARRHOEA By
J.
C.
FAYET
Physiopathologie de la Nu trition, I. N. R.A. , Theix, 63-Saint-Genes-Champanelle (near Clermont-Ferrand), France
SUMMA RY
Diarrhoeic calves were shown to be hypotonically dehydrated, their mean plasma osmolality decreasing significantly from 294 mosmolll when healthy to 287 mosmolll when diarrhoeic (P < 0·001 ) . Measurement of the tritiated water space and other body fluid phases is described . In healthy calves the following mean values for the various spaces were obtained: total body water 76.5 ± 2·4, extracellular fluid 50·2 ± 2·3 and intracellular water 26·6 ± 2·3; all expressed as percentage of body weight. In diarrhoeic calves the respective values obtained \I·ere 74.0 ± 2·8, 35"0 ± 2·0 and 39.0 ± 3· 7 per cent. INTROD UC TIO N
Previous studies by the author (Fayet, I 968a, b & c) h ave confirmed the observations made by other workers (Blaxter & Wood, 1953; Dalton, Fisher & McIntyre, 1965; Roy et al., 1959) that in di arrhoeic calves there is characteristically a loss in bodyweight, n egative sodium and potassium balance, hyponatraemia, hyperkalaemia, uraemia and a m etabolic acidosis. It has also been observed by measurem ent of antipyrine, thiocyanate and TI824 spaces that dia rrhoea was associated with a d ecrease in extracellular fluid volume but no cha nge in total body water when these param eters are expressed as a percent age of bodyweight. As results obtained with chemical m arkers may be questioned, the following study was m ad e, based on m easurem ent of total body water using tritiated water. In order to define the origin of the hypotonic d ehydration a study was made of the plasma and faecal osmolality . EX PERIME NTAL
Male Friesian or Jersey calves aged approximately one to four weeks were used for this experiment. The method of feeding and keeping the calves in m etabolic cages for urine a nd faecal collection has been previously described (Fayet, I968a ). Body water measurements. Eight m easurements were made on 7 h ealthy calves and 6 measurements on 4 diarrhoeic animals. Calves were fed milk in the morning and the blood sample required as a "blank" taken prior to inj ection
BRITISH VETERINARY JOURNAL,
127,
1
of the tritiated water. A weighed dose of tritiated water, 7·5 ,uCijkg. body weight, was given in IO-I 2 ml. of o·8 per cent NaCl through a jugular catheter. The catheter was then carefully rinsed with IO ml. of heparinized o·8 per cent sodium chloride solution. Heparinized venous blood samples were collected at intervals from 5 minutes to 30 hours after injection of the tritiated water (see Fig. I). Immediately after collection, the blood sample was centrifuged to separate the plasma; this was then stored in sealed tubes at 4 °C. The tritium in plasma was assayed by a modification of the technique described by Mehran & Gagnon (I g66). A molar hyamine chloride in methanol solution was carefully mixed with purified X-IOO Triton (5 : 4 v jv) and approximately o·g ml. of the mixture poured into a counting vial. The vial and its contents were weighed and then approximately I oo,ul. of plasma added, the exact amount of plasma added being determined by again weighing the vial and its contents. Duplicate estimates were made on all plasma samples collected. After the contents of the vial were mixed they were allowed to stand at room temperature for 24 hours; I7 ml. of liquid scintillator (4 g. PPO (Packard) and 50 mg. POPOP (Packard) /litre of toluene) were then added. An aliquot of the tritium solution used to inject the calves was, after a I : 20 dilution in saline solution, prepared in the same manner as the plasma samples. The vials were wiped with swabs soaked in 95 per cent ethanol, dried and kept in the dark at 6 oc for 48 hours. Samples were then counted, each on four occasions in a liquid scintillation spectrometer (Packard 3375). The counting efficiency, determined by external standardization under these conditions, is about 30 per cent.
Log of specifi c activity dpm / m l of p lasma water.
Rs(tl' 40,150e - 2 47h + 4 0 .800e-0·0098h
I
•I •
\••
~---~.---• -• ----------------------~4~0~,8~00~e:-o~o~o~9S~h-- • 4 5 .
- - - - - - - - - -· -
\g ,._
i~
!(tl, ,
.~
'~ 0
6
18
12
24
30
Hour s
Fig.
1.
Evolution of the specific radioactivity in plasma water after a single intravenous dose of tritiated water.
BODY FLUIDS OF CALVES WITH DIARRHOEA
39
Plasma water content. Plasma water content was determined on duplicate samples from each animal by dessication. The plasma was dessicated in glass dishes at go oc for 3-4 days until a constant dry weight was attained. Equation of the specific radioactivity in plasma water. From the predetermined plasma water content and the radioactivity of the plasma samples the activity in plasma water was calculated. The activity in the samples collected at intervals after injection of the tritiated water was then plotted against time on a semilogarithmic scale and the best line of fit calculated by the method of least squares. From Fig. 1 it can be seen that the activity is represented by two components, indicating an initial equilibration throughout the body and thereafter gradual excretion. The kinetics of distribution can be represented mathematically as Rt = A 1 e-A.lt + A 2e-"-2\ where Rt = specific activity at time "t". This equation is based on the premise that the pool of body water represents an open two compartments system, the elements of which have been described by Aubert & Milhaud (rg6o) and which is represented schematically by Fig. 2. Vi ....--.--
Vo
Vf
vu
Vr
._____, F
'--------'
Fig.
2
Scheme of the Elements of an Open Two Compartments System. Vi = rate of ingestion Va = rate of absorption Vf = endogenous faecal water F = whole faecal water Vr = respiratory elimination Vu = urinary excretion VT = total output from the pool M =accessible compartment (extracellular fluid) M 1 = unaccessible but quickly exchangeable compartment (intracellular fluid ) P = M + M, = Pool (total body water) V 1 = transfer rate between M and M,
t
TABLE I ~
FLUID COMPARTMENTS, TRANSFER RATE, TOTAL OUTPUT, ENDOGENOUS FAECAL WATER AND HALF-LIFE (T!) OF TQH IN HEALTHY AND DIARRHOEIC CALVES (MEAN AND S.D.)
~ ...... ....,
......
*Total body water p
*Extracellular fluid M
*Intracellular fluid
**Transfer rate
M1
v1
±
±
**Total ouput
VT
Endogenous faecal water per cent
[f}
I I ....,~
Tt
(days)
tJ:j
Healthy calves
76·5
Diarrhoeic calves
74'0
("t" test)
2·4
50'2
± 2·8
t
=
!•82
N.S.
±
2'3
26·6
35'0
± 2'0
2'3
± 3'7
39'0
(i)
=
I2·66
t
=
7'40
P<
o·OOI
p
<
0'001
± 311
723
(6)
(6)
(6) t
6I7
(7)
(7)
(6)
(No. ofmeasurements) Significance
±
(8)
(No. of measurements)
528
t
=
0'43
N.S.
±
7'37
4'33
±
95'9
± 1·96
102"0
t
=
N.S.
± 6·2
±
3'9
0'47
t
=
1•2
(6)
(6)
(6)
3'I
(7)
(7)
(7) 6·46
9'4
±
5'0
II ~
~
\lg ~
1'34
N.S.
t
±
N.S.
o·81
II ~ ~
:;I
*Water spaces are in percentages of bodyweight. •• In mi. hr.- 1 kg.- 1 of bodyweight.
RODY FLUIDS OF CALVES WITH DIARRHOEA
41
Plasma and faecal osmolality measurement. Measurements were made cryoscopically on fresh plasma using a Fiske* Model G66 Osmometer. Faecal osmolality was measured on faecal water which was obtained as follows. Diarrhoeic faeces, i.e. stools containing less than I 2 per cent dry matter, were carefully mixed in a homogenizer. An aliquot was then centrifuged at 40,000 g. for .15 minutes to separate a fluid supernatant for analysis. Normal faeces were initially diluted I: 4 with distilled water prior to similar treatment. This method gives a slight overestimate of normal faecal osmolality. RESULTS
In healthy calves the mean plasma water content observed was 93"5I ± S.D. o·87 per cent. In diarrhoeic calves the mean value was significantly lower (P < o·oo5), namely 92·I I ± o·52 per cent. Table I shows the volumes of the body fluid compartments, the transfer rates, total output, endogenous faecal water and half-life of the injected tritrium. Present results confirm previous findings (Fayet, I968c) for the volumes of the body fluids expressed as a percentage of bodyweight in healthy and diarrhoeic calves. On the basis of expressing results as a percentage of bodyweight, it appears that diarrhoea is associated with a decrease in extracellular fluid volume and increase in intracellular volume. Transfer rate (V 1 ) (see Fig. 2) between compartments M and M 1 , though slightly increased in diarrhoeic calves, was not significantly different from the value for healthy calves. The total water output from the pool, and the half-life, were not significantly affected by diarrhoea. Faecal water was, as expected, increased in the diarrhoeic animal but this appeared to be of endogenous (i.e. Vf) origin. Table II shows the results of plasma and faecal water measurements. Mean plasma osmolality decreased significantly in the diarrhoeic animal (P < o·ooi) while faecal osmolality was relatively constant although it was always hypertonic relative to the plasma level. However, shortly before death, plasma osmolality was sometimes observed to increase to as high as 340 mosmol. /1.
* Fiske Associates Inc.,
Uxbridge, Mass.
TABLE II PLASMA AND FAECAL OSMOLALITY ( MOSMOL/L ) IN HEALTHY OR DIARRHOEIC CALVES ( MEAN ± S.D.)
Plasma osmolality
Faecal osmolality
Healthy calves (No. of measurements)
294 ± 6 (I5I )
4I4 ± 73 (I 57)
Diarrhoeic calves (No. of measurements)
287 ± I2 (46)
400
Significance ("t" test)
P < o·oor
±
(44)
N.S.
6o
BRITISH VETERINARY JOURNAL,
I27, I
DISCUSSION
In the diarrhoeic calf there is an apparent discrepancy between the extent of the d ecrease in plasma osmolality and plasma water content, the difference between the mean values for healthy and diarrhoeic calves being significant at the levels P < o·ooi and P < o·oos respectively. This discrepancy may be explained in terms of the effect on plasma protein in the diarrhoeic animal. Plasma protein would contribute more to plasma dry matter content than to osmolality and forese eably in the dehydrated animal the plasma protein content may rise owing to hypovolaemia while the electrolyte contents, as has been shown by this work and by other authors, may either remain normal or below normal values. The values found for the tritrium space, while slightly higher, generally compare with the previously determined value for the antipyrine space (Fayet, Ig68a, b, c), namely 76·5 and 73·3 per cent respectively. Others have observed that the tritrium space is larger than the antipyrine space and this has been attributed to exchange of labile hydrogen ions during the initial equilibration period (Panaretto & Till, I963 ). For comparison, mean values for total body water in healthy calves determined by other workers using a variety of methods are shown in Table III. TABLE III BODY WATER IN HEALTHY CALVES
Authors
Method
Animals
Haigh, Moulton & Trowbridge (1920)
Dessication
Newborn Jersey Newborn Hereford
Ellenberger, Newlander & Jones (1950)
Chemical analysis
7 newborn
McFadden & Richards (1956)
Antipyrine space
5 Friesian one week old
Dalton ( 1964)
Urea space
25 Ayrshire one to two weeks old
Fayet (1968)
Antipyrine space
Phillips & Knox (1969)
Body water as percentage of bodyweight 73"4 72"4-73'5 74"2
12 Friesian one to three weeks old Tritiated water space 6 newborn
The values found for theM compartments (50·2 per cent) are similar to the thiocyanate space (44·3 per cent) in healthy calves; moreover the volume of this space is affected, in diarrhoeic calves, exactly as previously observed by the author when using chemical methods. It is always difficult to equate these values with the true extracellular volume for, as Dalton (I g64a) has pointed out, the space measured varies depending on the solute used, e.g. inulin, thiosulphate, radiosodium, thiocyanate. It is necessary to interpret with caution the volumes of body fluids expressed as a percentage of bodyweight. As Dalton (I g64b) described, the loss in body-
BODY FLUIDS OF CALVES WITH DIARRHOEA
43
weight during diarrhoea can be due to loss in body water and catabolism body tissue in variable and generally unknown proportions. Consequently, a single measurement of body water expressed as a percentage of bodyweight does not indicate absolutely whether the diarrhoeic animal is dehydrated nor the extent of its deficit. ACKNOWLEDGMENTS
The author would like to acknowledge the technical assistance of Messrs. P. Novel and J. Overwater. He is indebted to Dr R. G. Dalton for his advice and his help with the final preparation of the manuscript. REFERENCES
AuBERT,]. P. & MILHAUD, G. (I96o). Biochim. biophys. Acta., 39, I22. BLAXTER, K. L. & WooD, W. A. (I953). Vet. Rec., 65, 889. DALTON, R. G. (I964a). Br. vet.]., 120, I I7. DALTON, R. G. (I964b). Br. vet.]., 120, 378. DALTON, R. G., FISHER, E. W. & MciNTYRE, W. I. M. ( I965). Br. vet.]., I2I, 34ELLENBERGER, H. B., NEWLANDER, J. A. & joNES, C. H. (I950). Vermont Agric. exp. Stn. Bull., 5aa. FAYET, J. C. (I968a). Rech. Vet., I, 99· FAYET, J. C. (r968b). Rech. Vet., I, 109. FAYET,j. C. (r968c). Rech. Vet., 1, II7. HAIGH, L. D., MouLTON, C. R. & TROWBRIDGE, P. F. (1920). Missouri Agric. exp. Stn. Bull., 38. McFADDEN, P. L. & RicHARDs, C. R. ( r956). ]. Dairy Sci., 39, I438. MEHRAN, A. R. & GAGNON, A. ( r966). Archs int. Physiol. Biochim., 74, 549· PANARETTO, B. A. & TrLL, A. R. ( r963 ). Aust. J. agric. Res., I4, 926. PHILLIPS, R. W. & KNox, K. L. (r969). J. Dairy Sci., 52, r664. Rov, ]. H. B., SHILLAM, K. W. G., HAWKINs, G. M., LANG,]. M. & INGRAM, P. L. ( r959) . Br. J. Nutr., 13, 219. (Acceptedfor publication 30 June 1970) Osmolalite plasmatique et fecale, cinetique de l'eau et compartiments hydriques, chez les veaux nouveau-nes atteints de diarrhee (Fayet) Resume. On a montre que les veaux atteints de diarrhee etaient hypotoniquement deshydrates, l'osmolalite moyenne du plasma diminuant de facon significative de 294 milliosmol/1. quand ils etaient en bonne sante a 287 milliosmol/1. quand ils etaient atteints de diarrhee (P < o,oor). La mesure des compartiments hydriques, par l'eau tritiee, est decrite. Chez les veaux en bonne sante on a trouve les valeurs moyennes suivantes pour les divers compartiments; eau to tale du corps; 76,5 ± 2,4, liquide extracellulaire: 50,2 ± 2,3, et eau intracellulaire: 26,6 ± 2,3; toutes sont exprimees en pourcentage du poids du corps. Chez les veaux atteints de diarrhee on a obtenu respectivement les valeurs suivantes: 74,0 ± 2,8, 35,0 ± 2,0, et 39,0 ± 3, 7 pour cent. Plasma und fakale Osmolalitat, Wasserbewegung und Fliissigkeitsmengen bei neugeborenen Kalbern die an Diarrhoe Iitten (Fayet) Zusammenfassung. Kiilber, die an Diarrhoe litten, waren hypnotisch entwiissert, ihre durchschnittliche Plasma-Osmolalitiit verminderte sich signifikant von 294 Mosmol/1. im gesunden Zustand auf 287 Mosmol/1. bei vorhandener Diarrhoe (P < o,ooi) Messung des titrierten Wasservoluments und sonstiger Korperfliissigkeiten wird beschrieben. Bei gesunden Kiilbern wurden die folgenden Durchschnittsswerte fiir die verschiedenen Mengen gefunden: Gesamtwassermenge 76,5 ± 2,4; extrazelliiliire Fliissigkeit 50,2 ± 2,3; intrazelluliires Wasser
44
BRITISH VETERINARY jOURNAL,
127, 1
26,6 ± 2,3; alles ausgedriickt als Prozent des Ki:irpergewichts. Bei Kalbern mit D iarrhoe waren die entsprechenden Werte 74,0 ± 2,8; 35,0 ± 2,0 und 39,0 ± 3,7 Prozent. La osmolalidad del plasma y fecal, cinetica del agua y comparthnientos del fluido corporal en terneros recien nacidos con diarrea (Fayet) Res UD1en. Se mostr6 que terneros diarn!icos estaban hipo6tnicamente deshidratados; la osmolalidad media de su plasma disminuy6 significativamente de 294 mosmol/1. cuando sanos a 287 mosmol/1. cuando diarreicos (P < o,oo 1) . Se describen mediciones del espacio acuoso graduado y otras fases del fluido corp6reo. Se obtuvieron los siguientes valores medics para los varios espacios en terneros sanos: agua corp6rea total, 76,5 ± 2,4; fluido extracelular, 50,2 ± 2,3 y agua intracelular, 26,6 ± 2,3: todos ellos expresados como porcentaje de peso corporal. En los terneros diarreicos, los valores respectivos obtenidos fueron 74.,0 ± 2,8; 35,0 ± 2,0 y 39,0 ± 3, 7 por ciento.
J.
(197 1), 127, 37
PLASMA AND FAECAL OSMOLALITY, WATER KINETICS AND BODY FLUID COMPARTMENTS IN NEONATAL CALVES WITH DIARRHOEA By
J.
C.
FAYET
Physiopathologie de la Nu trition, I. N. R.A. , Theix, 63-Saint-Genes-Champanelle (near Clermont-Ferrand), France
SUMMA RY
Diarrhoeic calves were shown to be hypotonically dehydrated, their mean plasma osmolality decreasing significantly from 294 mosmolll when healthy to 287 mosmolll when diarrhoeic (P < 0·001 ) . Measurement of the tritiated water space and other body fluid phases is described . In healthy calves the following mean values for the various spaces were obtained: total body water 76.5 ± 2·4, extracellular fluid 50·2 ± 2·3 and intracellular water 26·6 ± 2·3; all expressed as percentage of body weight. In diarrhoeic calves the respective values obtained \I·ere 74.0 ± 2·8, 35"0 ± 2·0 and 39.0 ± 3· 7 per cent. INTROD UC TIO N
Previous studies by the author (Fayet, I 968a, b & c) h ave confirmed the observations made by other workers (Blaxter & Wood, 1953; Dalton, Fisher & McIntyre, 1965; Roy et al., 1959) that in di arrhoeic calves there is characteristically a loss in bodyweight, n egative sodium and potassium balance, hyponatraemia, hyperkalaemia, uraemia and a m etabolic acidosis. It has also been observed by measurem ent of antipyrine, thiocyanate and TI824 spaces that dia rrhoea was associated with a d ecrease in extracellular fluid volume but no cha nge in total body water when these param eters are expressed as a percent age of bodyweight. As results obtained with chemical m arkers may be questioned, the following study was m ad e, based on m easurem ent of total body water using tritiated water. In order to define the origin of the hypotonic d ehydration a study was made of the plasma and faecal osmolality . EX PERIME NTAL
Male Friesian or Jersey calves aged approximately one to four weeks were used for this experiment. The method of feeding and keeping the calves in m etabolic cages for urine a nd faecal collection has been previously described (Fayet, I968a ). Body water measurements. Eight m easurements were made on 7 h ealthy calves and 6 measurements on 4 diarrhoeic animals. Calves were fed milk in the morning and the blood sample required as a "blank" taken prior to inj ection
BRITISH VETERINARY JOURNAL,
127,
1
of the tritiated water. A weighed dose of tritiated water, 7·5 ,uCijkg. body weight, was given in IO-I 2 ml. of o·8 per cent NaCl through a jugular catheter. The catheter was then carefully rinsed with IO ml. of heparinized o·8 per cent sodium chloride solution. Heparinized venous blood samples were collected at intervals from 5 minutes to 30 hours after injection of the tritiated water (see Fig. I). Immediately after collection, the blood sample was centrifuged to separate the plasma; this was then stored in sealed tubes at 4 °C. The tritium in plasma was assayed by a modification of the technique described by Mehran & Gagnon (I g66). A molar hyamine chloride in methanol solution was carefully mixed with purified X-IOO Triton (5 : 4 v jv) and approximately o·g ml. of the mixture poured into a counting vial. The vial and its contents were weighed and then approximately I oo,ul. of plasma added, the exact amount of plasma added being determined by again weighing the vial and its contents. Duplicate estimates were made on all plasma samples collected. After the contents of the vial were mixed they were allowed to stand at room temperature for 24 hours; I7 ml. of liquid scintillator (4 g. PPO (Packard) and 50 mg. POPOP (Packard) /litre of toluene) were then added. An aliquot of the tritium solution used to inject the calves was, after a I : 20 dilution in saline solution, prepared in the same manner as the plasma samples. The vials were wiped with swabs soaked in 95 per cent ethanol, dried and kept in the dark at 6 oc for 48 hours. Samples were then counted, each on four occasions in a liquid scintillation spectrometer (Packard 3375). The counting efficiency, determined by external standardization under these conditions, is about 30 per cent.
Log of specifi c activity dpm / m l of p lasma water.
Rs(tl' 40,150e - 2 47h + 4 0 .800e-0·0098h
I
•I •
\••
~---~.---• -• ----------------------~4~0~,8~00~e:-o~o~o~9S~h-- • 4 5 .
- - - - - - - - - -· -
\g ,._
i~
!(tl, ,
.~
'~ 0
6
18
12
24
30
Hour s
Fig.
1.
Evolution of the specific radioactivity in plasma water after a single intravenous dose of tritiated water.
BODY FLUIDS OF CALVES WITH DIARRHOEA
39
Plasma water content. Plasma water content was determined on duplicate samples from each animal by dessication. The plasma was dessicated in glass dishes at go oc for 3-4 days until a constant dry weight was attained. Equation of the specific radioactivity in plasma water. From the predetermined plasma water content and the radioactivity of the plasma samples the activity in plasma water was calculated. The activity in the samples collected at intervals after injection of the tritiated water was then plotted against time on a semilogarithmic scale and the best line of fit calculated by the method of least squares. From Fig. 1 it can be seen that the activity is represented by two components, indicating an initial equilibration throughout the body and thereafter gradual excretion. The kinetics of distribution can be represented mathematically as Rt = A 1 e-A.lt + A 2e-"-2\ where Rt = specific activity at time "t". This equation is based on the premise that the pool of body water represents an open two compartments system, the elements of which have been described by Aubert & Milhaud (rg6o) and which is represented schematically by Fig. 2. Vi ....--.--
Vo
Vf
vu
Vr
._____, F
'--------'
Fig.
2
Scheme of the Elements of an Open Two Compartments System. Vi = rate of ingestion Va = rate of absorption Vf = endogenous faecal water F = whole faecal water Vr = respiratory elimination Vu = urinary excretion VT = total output from the pool M =accessible compartment (extracellular fluid) M 1 = unaccessible but quickly exchangeable compartment (intracellular fluid ) P = M + M, = Pool (total body water) V 1 = transfer rate between M and M,
t
TABLE I ~
FLUID COMPARTMENTS, TRANSFER RATE, TOTAL OUTPUT, ENDOGENOUS FAECAL WATER AND HALF-LIFE (T!) OF TQH IN HEALTHY AND DIARRHOEIC CALVES (MEAN AND S.D.)
~ ...... ....,
......
*Total body water p
*Extracellular fluid M
*Intracellular fluid
**Transfer rate
M1
v1
±
±
**Total ouput
VT
Endogenous faecal water per cent
[f}
I I ....,~
Tt
(days)
tJ:j
Healthy calves
76·5
Diarrhoeic calves
74'0
("t" test)
2·4
50'2
± 2·8
t
=
!•82
N.S.
±
2'3
26·6
35'0
± 2'0
2'3
± 3'7
39'0
(i)
=
I2·66
t
=
7'40
P<
o·OOI
p
<
0'001
± 311
723
(6)
(6)
(6) t
6I7
(7)
(7)
(6)
(No. ofmeasurements) Significance
±
(8)
(No. of measurements)
528
t
=
0'43
N.S.
±
7'37
4'33
±
95'9
± 1·96
102"0
t
=
N.S.
± 6·2
±
3'9
0'47
t
=
1•2
(6)
(6)
(6)
3'I
(7)
(7)
(7) 6·46
9'4
±
5'0
II ~
~
\lg ~
1'34
N.S.
t
±
N.S.
o·81
II ~ ~
:;I
*Water spaces are in percentages of bodyweight. •• In mi. hr.- 1 kg.- 1 of bodyweight.
RODY FLUIDS OF CALVES WITH DIARRHOEA
41
Plasma and faecal osmolality measurement. Measurements were made cryoscopically on fresh plasma using a Fiske* Model G66 Osmometer. Faecal osmolality was measured on faecal water which was obtained as follows. Diarrhoeic faeces, i.e. stools containing less than I 2 per cent dry matter, were carefully mixed in a homogenizer. An aliquot was then centrifuged at 40,000 g. for .15 minutes to separate a fluid supernatant for analysis. Normal faeces were initially diluted I: 4 with distilled water prior to similar treatment. This method gives a slight overestimate of normal faecal osmolality. RESULTS
In healthy calves the mean plasma water content observed was 93"5I ± S.D. o·87 per cent. In diarrhoeic calves the mean value was significantly lower (P < o·oo5), namely 92·I I ± o·52 per cent. Table I shows the volumes of the body fluid compartments, the transfer rates, total output, endogenous faecal water and half-life of the injected tritrium. Present results confirm previous findings (Fayet, I968c) for the volumes of the body fluids expressed as a percentage of bodyweight in healthy and diarrhoeic calves. On the basis of expressing results as a percentage of bodyweight, it appears that diarrhoea is associated with a decrease in extracellular fluid volume and increase in intracellular volume. Transfer rate (V 1 ) (see Fig. 2) between compartments M and M 1 , though slightly increased in diarrhoeic calves, was not significantly different from the value for healthy calves. The total water output from the pool, and the half-life, were not significantly affected by diarrhoea. Faecal water was, as expected, increased in the diarrhoeic animal but this appeared to be of endogenous (i.e. Vf) origin. Table II shows the results of plasma and faecal water measurements. Mean plasma osmolality decreased significantly in the diarrhoeic animal (P < o·ooi) while faecal osmolality was relatively constant although it was always hypertonic relative to the plasma level. However, shortly before death, plasma osmolality was sometimes observed to increase to as high as 340 mosmol. /1.
* Fiske Associates Inc.,
Uxbridge, Mass.
TABLE II PLASMA AND FAECAL OSMOLALITY ( MOSMOL/L ) IN HEALTHY OR DIARRHOEIC CALVES ( MEAN ± S.D.)
Plasma osmolality
Faecal osmolality
Healthy calves (No. of measurements)
294 ± 6 (I5I )
4I4 ± 73 (I 57)
Diarrhoeic calves (No. of measurements)
287 ± I2 (46)
400
Significance ("t" test)
P < o·oor
±
(44)
N.S.
6o
BRITISH VETERINARY JOURNAL,
I27, I
DISCUSSION
In the diarrhoeic calf there is an apparent discrepancy between the extent of the d ecrease in plasma osmolality and plasma water content, the difference between the mean values for healthy and diarrhoeic calves being significant at the levels P < o·ooi and P < o·oos respectively. This discrepancy may be explained in terms of the effect on plasma protein in the diarrhoeic animal. Plasma protein would contribute more to plasma dry matter content than to osmolality and forese eably in the dehydrated animal the plasma protein content may rise owing to hypovolaemia while the electrolyte contents, as has been shown by this work and by other authors, may either remain normal or below normal values. The values found for the tritrium space, while slightly higher, generally compare with the previously determined value for the antipyrine space (Fayet, Ig68a, b, c), namely 76·5 and 73·3 per cent respectively. Others have observed that the tritrium space is larger than the antipyrine space and this has been attributed to exchange of labile hydrogen ions during the initial equilibration period (Panaretto & Till, I963 ). For comparison, mean values for total body water in healthy calves determined by other workers using a variety of methods are shown in Table III. TABLE III BODY WATER IN HEALTHY CALVES
Authors
Method
Animals
Haigh, Moulton & Trowbridge (1920)
Dessication
Newborn Jersey Newborn Hereford
Ellenberger, Newlander & Jones (1950)
Chemical analysis
7 newborn
McFadden & Richards (1956)
Antipyrine space
5 Friesian one week old
Dalton ( 1964)
Urea space
25 Ayrshire one to two weeks old
Fayet (1968)
Antipyrine space
Phillips & Knox (1969)
Body water as percentage of bodyweight 73"4 72"4-73'5 74"2
12 Friesian one to three weeks old Tritiated water space 6 newborn
The values found for theM compartments (50·2 per cent) are similar to the thiocyanate space (44·3 per cent) in healthy calves; moreover the volume of this space is affected, in diarrhoeic calves, exactly as previously observed by the author when using chemical methods. It is always difficult to equate these values with the true extracellular volume for, as Dalton (I g64a) has pointed out, the space measured varies depending on the solute used, e.g. inulin, thiosulphate, radiosodium, thiocyanate. It is necessary to interpret with caution the volumes of body fluids expressed as a percentage of bodyweight. As Dalton (I g64b) described, the loss in body-
BODY FLUIDS OF CALVES WITH DIARRHOEA
43
weight during diarrhoea can be due to loss in body water and catabolism body tissue in variable and generally unknown proportions. Consequently, a single measurement of body water expressed as a percentage of bodyweight does not indicate absolutely whether the diarrhoeic animal is dehydrated nor the extent of its deficit. ACKNOWLEDGMENTS
The author would like to acknowledge the technical assistance of Messrs. P. Novel and J. Overwater. He is indebted to Dr R. G. Dalton for his advice and his help with the final preparation of the manuscript. REFERENCES
AuBERT,]. P. & MILHAUD, G. (I96o). Biochim. biophys. Acta., 39, I22. BLAXTER, K. L. & WooD, W. A. (I953). Vet. Rec., 65, 889. DALTON, R. G. (I964a). Br. vet.]., 120, I I7. DALTON, R. G. (I964b). Br. vet.]., 120, 378. DALTON, R. G., FISHER, E. W. & MciNTYRE, W. I. M. ( I965). Br. vet.]., I2I, 34ELLENBERGER, H. B., NEWLANDER, J. A. & joNES, C. H. (I950). Vermont Agric. exp. Stn. Bull., 5aa. FAYET, J. C. (I968a). Rech. Vet., I, 99· FAYET, J. C. (r968b). Rech. Vet., I, 109. FAYET,j. C. (r968c). Rech. Vet., 1, II7. HAIGH, L. D., MouLTON, C. R. & TROWBRIDGE, P. F. (1920). Missouri Agric. exp. Stn. Bull., 38. McFADDEN, P. L. & RicHARDs, C. R. ( r956). ]. Dairy Sci., 39, I438. MEHRAN, A. R. & GAGNON, A. ( r966). Archs int. Physiol. Biochim., 74, 549· PANARETTO, B. A. & TrLL, A. R. ( r963 ). Aust. J. agric. Res., I4, 926. PHILLIPS, R. W. & KNox, K. L. (r969). J. Dairy Sci., 52, r664. Rov, ]. H. B., SHILLAM, K. W. G., HAWKINs, G. M., LANG,]. M. & INGRAM, P. L. ( r959) . Br. J. Nutr., 13, 219. (Acceptedfor publication 30 June 1970) Osmolalite plasmatique et fecale, cinetique de l'eau et compartiments hydriques, chez les veaux nouveau-nes atteints de diarrhee (Fayet) Resume. On a montre que les veaux atteints de diarrhee etaient hypotoniquement deshydrates, l'osmolalite moyenne du plasma diminuant de facon significative de 294 milliosmol/1. quand ils etaient en bonne sante a 287 milliosmol/1. quand ils etaient atteints de diarrhee (P < o,oor). La mesure des compartiments hydriques, par l'eau tritiee, est decrite. Chez les veaux en bonne sante on a trouve les valeurs moyennes suivantes pour les divers compartiments; eau to tale du corps; 76,5 ± 2,4, liquide extracellulaire: 50,2 ± 2,3, et eau intracellulaire: 26,6 ± 2,3; toutes sont exprimees en pourcentage du poids du corps. Chez les veaux atteints de diarrhee on a obtenu respectivement les valeurs suivantes: 74,0 ± 2,8, 35,0 ± 2,0, et 39,0 ± 3, 7 pour cent. Plasma und fakale Osmolalitat, Wasserbewegung und Fliissigkeitsmengen bei neugeborenen Kalbern die an Diarrhoe Iitten (Fayet) Zusammenfassung. Kiilber, die an Diarrhoe litten, waren hypnotisch entwiissert, ihre durchschnittliche Plasma-Osmolalitiit verminderte sich signifikant von 294 Mosmol/1. im gesunden Zustand auf 287 Mosmol/1. bei vorhandener Diarrhoe (P < o,ooi) Messung des titrierten Wasservoluments und sonstiger Korperfliissigkeiten wird beschrieben. Bei gesunden Kiilbern wurden die folgenden Durchschnittsswerte fiir die verschiedenen Mengen gefunden: Gesamtwassermenge 76,5 ± 2,4; extrazelliiliire Fliissigkeit 50,2 ± 2,3; intrazelluliires Wasser
44
BRITISH VETERINARY jOURNAL,
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26,6 ± 2,3; alles ausgedriickt als Prozent des Ki:irpergewichts. Bei Kalbern mit D iarrhoe waren die entsprechenden Werte 74,0 ± 2,8; 35,0 ± 2,0 und 39,0 ± 3,7 Prozent. La osmolalidad del plasma y fecal, cinetica del agua y comparthnientos del fluido corporal en terneros recien nacidos con diarrea (Fayet) Res UD1en. Se mostr6 que terneros diarn!icos estaban hipo6tnicamente deshidratados; la osmolalidad media de su plasma disminuy6 significativamente de 294 mosmol/1. cuando sanos a 287 mosmol/1. cuando diarreicos (P < o,oo 1) . Se describen mediciones del espacio acuoso graduado y otras fases del fluido corp6reo. Se obtuvieron los siguientes valores medics para los varios espacios en terneros sanos: agua corp6rea total, 76,5 ± 2,4; fluido extracelular, 50,2 ± 2,3 y agua intracelular, 26,6 ± 2,3: todos ellos expresados como porcentaje de peso corporal. En los terneros diarreicos, los valores respectivos obtenidos fueron 74.,0 ± 2,8; 35,0 ± 2,0 y 39,0 ± 3, 7 por ciento.