This article was downloaded by: [University of Arizona] On: 05 February 2015, At: 01:15 Publisher: Taylor & Francis Informa Ltd Registered in England and Wales Registered Number: 1072954 Registered office: Mortimer House, 37-41 Mortimer Street, London W1T 3JH, UK
British Poultry Science Publication details, including instructions for authors and subscription information: http://www.tandfonline.com/loi/cbps20
Energy and nitrogen metabolism of diseased chickens: Interaction of Ascaridia galli infestation and vitamin a status T. R. Walker
a b
& D. J. Farrell
a
a
Departments of Agricultural Biology and Biochemistry and Nutrition , University of New England , Armidale, N.S.W., 2351, Australia b
NRM Group , P.O. Box 514, Auckland, New Zealand Published online: 08 Nov 2007.
To cite this article: T. R. Walker & D. J. Farrell (1976) Energy and nitrogen metabolism of diseased chickens: Interaction of Ascaridia galli infestation and vitamin a status, British Poultry Science, 17:1, 63-77, DOI: 10.1080/00071667608416251 To link to this article: http://dx.doi.org/10.1080/00071667608416251
PLEASE SCROLL DOWN FOR ARTICLE Taylor & Francis makes every effort to ensure the accuracy of all the information (the “Content”) contained in the publications on our platform. However, Taylor & Francis, our agents, and our licensors make no representations or warranties whatsoever as to the accuracy, completeness, or suitability for any purpose of the Content. Any opinions and views expressed in this publication are the opinions and views of the authors, and are not the views of or endorsed by Taylor & Francis. The accuracy of the Content should not be relied upon and should be independently verified with primary sources of information. Taylor and Francis shall not be liable for any losses, actions, claims, proceedings, demands, costs, expenses, damages, and other liabilities whatsoever or howsoever caused arising directly or indirectly in connection with, in relation to or arising out of the use of the Content. This article may be used for research, teaching, and private study purposes. Any substantial or systematic reproduction, redistribution, reselling, loan, sub-licensing, systematic supply, or distribution in any form to anyone is expressly forbidden. Terms
Downloaded by [University of Arizona] at 01:15 05 February 2015
& Conditions of access and use can be found at http://www.tandfonline.com/page/ terms-and-conditions
Br. Poult. Sci., 17: 63-77.
1976
Longman: printed in Great Britain
ENERGY AND NITROGEN METABOLISM OF DISEASED CHICKENS: INTERACTION OF ASCARIDIA GALLI INFESTATION AND VITAMIN A STATUS T. R. WALKER1 AND D. J. FARRELL
Downloaded by [University of Arizona] at 01:15 05 February 2015
Departments of Agricultural Biology and Biochemistry and Nutrition, University of New England, Armidale, N.S.W. 2351, Australia Received for publication 10th March 1975
1. Effects of Ascaridia galli infection on the energy and nitrogen (N) metabolism were studied on groups of 5 cross-bred cockerels aged about 5 weeks and given a diet deficient or adequate in vitamin A at two levels of feeding in respiration chambers. 2. Metabolisability of dietary energy was 67% and N retention 33% in infected chickens compared with 71 and 4 1 % respectively, in uninfected chickens. 3. Maintenance energy requirement of vitamin A-deficient birds was 882 kJ/kgW d compared with 998 kJ/kgW d for normal birds. N balance of the deficient chickens was also less when compared at the same energy balance. Infection did not affect maintenance energy requirement nor N balance. 4. Starvation heat production of infected chickens (619 kJ/kgW d) was higher than that of uninfected controls (586 kJ/kgW d). When infection treatments were combined, vitamin A-adequate chickens had a higher heat production (615 kJ/kg d) than the vitamin A-deficient (580 kJ/kgW d). Endogenous N excretion (mg/gW) was less in vitamin A-deficient than in adequate, starved birds. 5. Deficient chickens had undetectable liver reserves of vitamin A and only very low plasma concentrations. There was a difference in the length of larvae (17 d after infection) associated with vitamin A status, and with level of feeding. INTRODUCTION
The margin of profitability in the poultry industry is declining due mainly to increased cost of food ingredients. Thus definition of areas where food utilisation can be improved is of importance. One such area is the intimate relationship between nutrition and disease. It is known that nutritional status affects resistance to 1
Present address: NRM Group, P.O. Box 514, Auckland, New Zealand. 63
Downloaded by [University of Arizona] at 01:15 05 February 2015
64
T. R. WALKER AND D. J. FARRELL
disease, and disease status affects food intake and often its utilisation. However, the mechanisms by which disease affects nutritional status are not well denned. This paper, on nematode infestation, is the first of a series investigating, in chickens, the mode of action of some diseases on nutritional status and on the utilisation of dietary protein and energy. Animals infected with gastro-intestinal nematodes characteristically have impaired productivity associated with inappetance. In addition, digestive function and certain metabolic processes, particularly those related to energy and nitrogen (N) metabolism, may be deranged in nematode-infected ruminants and rats (Symons, 1969; Steel, 1974). Apart from the characteristic reduction in food consumption and growth, there is practically no information on the effects of nematodes on poultry. Ascaridia galli is the most common nematode parasite of poultry. It is most harmful between approximately 10 and 17 d after infection when the developing larvae penetrate the intestinal mucosa (Ackert and Herrick, 1928). Chickens fed on vitamin A-deficient diets harbour larger numbers of larvae which grow more rapidly (Ackbert et al., 1931), compared with birds on adequate diets. It would be anticipated that A. galli infections would not only cause a depression in food consumption but might also modify digestion and absorption of nutrients. Heat production, and therefore availability of metabolisable energy (ME), may also be influenced, since Horak and Clark (1966) reported elevated rectal temperatures in sheep infected with Oesophagostomum columbianum.
The experiments reported here were designed to study, in respiration chambers, the effects of A. galli infection of growing chickens on the ME of the diet, and energy and N balance. Interactions between vitamin A status and infection were also investigated by using adequately nourished and vitamin A-deficient chickens. A preliminary report of some of the work was presented by Farrell and Walker (1974).
MATERIALS AND METHODS
Chickens
One-day-old Australorp x White Leghorn cockerels were housed in electrically heated brooders and offered either a vitamin A-deficient or an adequate mash diet with a ME content of 12-1 ±0-1 MJ/kg, and a crude protein (Nx 6-25) content of 234%. The vitamin A-deficient diet had the following composition (g/kg): wheat, 735; soyabean meal, 130; meat meal, 130; sodium chloride, 2-5; and a vitamin-mineral premix (free of vitamin A) 2*5. The vitamin A-adequate diet had the same composition, supplemented with stabilised beadlets of retinyl esters (Rovimix A-500—Hoffman-La Roche A. Co. Ltd) to provide 3000 fig retinol/kg. At 18 d of age, chickens were intubated per os with either 500 ± 10 infective A. galli eggs suspended in a sugar solution, or with a sugar solution alone for control chickens (Hansen et al., 1954). The infective eggs were produced by taking eggs from mature female worms and incubating them at 30 °C for 25 d (Hansen et al., 1954). Sufficient chickens were reared to enable the five required for each treatment to be selected from approximately 30 chickens. The chickens were wing banded at
65
EFFECTS OF A. GALLI ON METABOLISM
7 d of age and weighed prior to selection. The five chickens chosen for each treatment were selected for uniformity of live-weight (W) such that each of the three calorimeters contained chickens with a similar total weight and range of weights. Experimental plan
Downloaded by [University of Arizona] at 01:15 05 February 2015
Measurements were made on groups of chickens in respiration chambers and offered various amounts of food over a 4- or 5-d period. Details are given in Table 1. Calorimetric measurements were also made on groups of five starved chickens for approximately 22 h following 30 h of food deprivation. These starvation measurements were made on chickens previously used for the feeding experiments and similar measurements were made on other chickens selected from the same groups. Details are given in Table 2. TABLE 1 Vitamin A status, infection treatment, age range, level of food intake and duration of measurement of groups of five fed chickens observed during 4 to 5 consecutive d in respiration chambers
Experiment code
K 1
4
Respiration chamber number 1 2 3
Vitamin A status1 D D
A.galli infection status2 -
D A
1 2 3 1 2 3 1 2 3
Ad libitum 70% of ad libitum
Pair-fed to chamber 1
A
1 2
Level of food intake
Duration of measurement (d)
}
Ad libitum —
Pair-fed to chamber 1
A A A
+ +
Ad libitum 70% of ad libitum
D D A
+ +
Ad libitum 70% of ad libitum
Pair-fed to chamber 1
Age range of chickens3 (d) 28 to 33
36 to 40
}
28 to 33
27 to 32
Pair-fed to chamber 1
A = adequate; D = deficient. + = infected; — = uninfected. Age at commencement and termination of measurements.
Respiration chambers
Three indirect closed-circuit respiration chambers were described by Farrell (1972) and incorporated the minor modifications of Farrell (1974). Experimental procedure
Feeding experiments. Chickens were accustomed to the calorimeters for 2 d prior to the commencement of measurements. The temperature in the respiration chambers was 30+1 °C, and the relative humidity 65 to 75% during the 4 or 5 consecutive days of measurement. Illumination was continous. Chickens were weighed at the commencement and conclusion of each experiment.
66
T. R. WALKER AND D. J. FARRELL
The chambers were opened for approximately 2 h each day during which time the procedures described below were carried out. The commencement and conclusion time for each run was recorded to the nearest minute. Measurements were corrected to 24 h by extrapolation from the actual duration of each run. Weighed amounts of food were offered each day, the restricted groups receiving an amount of food based on 70% of the consumption of the ad libitum group on the previous day. Birds in the control group (Chamber 3) were pair-fed to treated TABLE 2
Downloaded by [University of Arizona] at 01:15 05 February 2015
Prior treatment, vitamin A status, infection treatment and age of groups of Jive chickens obsevedfor 1 d in respiration chambers following 30 h of food deprivation Experiment code
Prior treatment of chickens1
Respiration chamber number n
f
!
ib f L
A
A. galli infection treatment3
Age (d)
D
-
W2
D
_
•
-I
I'
A
-
J
1
U5
p
D
-
^2
D
_
Is
A
A
{j
j
:
}42
A
fl ^2
A A
+ +
"I V35
p
A
+
]
J2 (3 •
A A
+
U6 J
P
D
B
B
f I
Vitamin A status2
\2 B
L36
J
+
1
D
+
p
D
+
1
12
D
+
V-35
\3
A
-
J
.
'
U4
x
A = chickens previously measured during feeding experiments, B = chickens selected from the same groups as A, but not previously measured. 2 A = adequate; D = deficient. 3 + = infected; — = uninfected.
birds in chamber 1. Spilled food was separated from excreta, weighed and the net daily intake calculated. Excreta were removed each day from a weighed polyethylene sheet placed below each cage, and stored at — 15 °C. The weight of traces of excreta remaining on the sheet was determined following air drying. Daily excreta samples were bulked over the 4- or 5-d period of measurement and stored at —15 °C for later analyses.
EFFECTS OF A. GALLI ON METABOLISM
67
Starvation experiments
Similar procedures to those described above for feeding experiments were used for starvation experiments made over approximately 22 h. Endogenous excreta were collected on polyethylene sheets, air dried, weighed and stored for later analyses.
Downloaded by [University of Arizona] at 01:15 05 February 2015
Analytical procedures
At the conclusion of starvation measurements a 2 ml blood sample was taken by cardiac puncture from each chicken, centrifuged and the plasma stored at —15 °C. The chickens were then slaughtered, the livers removed and stored at —15 °C and the intestinal tracts removed for digestion in pepsin solution and subsequent measurement of the number and length of A. galli larvae present, with the aid of a binocular microscope and camera lucida (Sprent et al,, 1967). The vitamin A concentrations of the thawed plasma samples were determined fluorometrically by the method of Kahan (1966) using the modification to extraction suggested by Thompson et al. (1971). Liver vitamin A concentration was determined by direct solvent extraction (Hinds et al., 1968) with acetone: petroleum ether ( 1 : 1 ) followed by spectrophotometric measurement using trichloroacetic acid as the chromogenic agent (Bayfield, 1971). Food and endogenous excreta were finely ground and stored in air-tight containers. Similarly, frozen excreta from the feeding experiments were dried to a constant weight in a freeze-dryer, weighed and finely ground. Representative subsamples were stored in air-tight containers for subsequent energy determination in a adiabatic bomb calorimeter, and N determination using a micro-Kjeldahl procedure. Calculation of results
Heat production was calculated, without correlation for urinary N loss, using the equation of Romijn and Lokhorst (1964). ME concentration of the diet was calculated by the difference in food energy intake and excreta energy output. No N correction factor was applied for the reasons suggested by Vohra (1972). Energy balance was calculated for fed chickens as the difference between ME intake and heat production, and for starved chickens as the summation of heat production and energy content of endogenous excreta, collected over the same time interval. N balance was calculated as the difference between food N and excreta N measured over the same time interval. Biometrical methods
Results from all experiments were pooled for the appropriate analysis unless otherwise indicated. Pooling of results was considered to be valid since all experiments were conducted with cockerels of the same strain obtained from the same hatchery, fed on the same diets, infected with the same worm egg culture and observed at similar ages and live-weights under similar experimental conditions. Results were analysed statistically by conventional use of Students " t" test and analyses of variance and covariance (Snedecor and Cochran, 1967) as appropriate, except for the analysis of N excreted per unit of body weight (W) lost during
Downloaded by [University of Arizona] at 01:15 05 February 2015
O OS
TABLE 3 Weight change, food consumption, metabolisable energy and nitrogen intake, metabolisability of dietary energy, energy balance and nitrogen retention of groups of five chickens observed during 4 to 5 consecutive d of feeding in respiration chambers
Code la
..
Chamber number fl •{ 2 [3
Group live-weight (g). , * > Initial Mean Gain 1130 1254 248 1131 1197 132 1217 1348 263
Gain (%) 21-9 11-7 . 21-6
Food consumption (g/d) 137-8 102-1 144-8
Metabolisability of dietary energy (%) 72-4 70-4 71-0
ME intake (kj/d) 1684 1213 1736
Heat production (kj/d) 1298 1068 1510
Energy balance (kj/d) 386 146 226
, Intake (g/d) 5-16 3-82 5-41
Nitrogen * , Balance Retention (g/d) (%) 2-33 45-3 1-32 34-5 2-32 42-9
H L $ r> g fa > §
fl \2
1346 1463
1409 1536
127 147
9-4 10-0
140-5 132-1
71-5 73-6
1696 1643
1344 1520
352 123
5-25 4-94
2-02 2-12
38-5 42-9
2
f 1 \ 2 [3
1353 1346 1314
1504 1396 1498
302 99 368
22-3 7-4 28-0
199-2 131-3 180-0
65-3 660 71-7
2197 1463 2180
1791 1403 1605
406 61 574
7-45 4-91 6-73
2-83 1-44 2-99
38-0 29-3 44-4
^ g pa
fl ^2 [3
1163 1184 1229
1257 1217 1331
187 66 203
16-1 5-6 16-5
122-6 92-5 132-6
69-2 66-6 70-4
1432 1041 1578
1240 1075 1432
193 -33 145
4-59 3-46 4-96
1-65 1-02 2-13
360 29-5 42-9
r
3
See Table 1 for details of experimental plan.
o
r
69
EFFECTS OF A. GALLI ON METABOLISM
Downloaded by [University of Arizona] at 01:15 05 February 2015
starvation. In this latter statistic, differences in weight loss (g/kg W) between groups of chickens which had been used previously for feeding measurements and those which had not, resulted in variation between replicates of each experiment. This variation was overcome by subtracting the treated group values (chambers 1 and 2) from the control group values (chamber 3) within each experiment. From the data thereby obtained, the main effects of vitamin A deficiency and infection with A. galli and the 2-factor interaction were estimated by orthogonal linear functions of the differences between the treated groups and the control groups. Thus the deficiency effect was determined by adding the transformed means of experiments 1 and 3 and subtracting the mean of experiment 2. A similar combination of transformed means between experiments gave estimates of the infection effect and the 2factor interaction (Snedecor and Cochran, 1967). Independent tests of the main effects and the interation were performed using the pooled within-run variation.
RESULTS
Live-weight change, food consumption, metabolisability of energy, energy balance and N retention of chickens observed during feeding experiments are shown in Tables 3 and 4. Live-weight, heat production, and energy and N balance of chickens observed during starvation experiments are shown in Table 4. These results are pooled between experiments and grouped according to treatment.
FABLE 4 4 status, infection treatment, weight, heat production and energy and W balance of groups of Jive chickens observed during starvation
Infection treatment
Vitamin A status
Adequate Uninfected
*
Deficient
Group liveweight
Group weight loss
(g)
(g) 79 93 105 78 108 105 119
"1244 1306 1359 1451 1519 1629 1679 T1139 1226 •I 1325 1636
[1664 r
Adequate Infected
fl301 J 1502
67 89 86
139 135
Heat production OJ/d)
N
1049
Energy balance (kj/d) -898 -890 -979 -953 -1014 -1076 -1192
balance fe/d) -2-20 -1-92 -2-18 -1-77 -1-95 -2-05 2-23
580 694 761 943 979
-668 -810 -881 -1080 -1119
-1-41 -1-92 -1-72 -2-25 -2-20
805
-2-30 -2-44 -2-13 -1-81 -1-58 -1-75 -1.86 -1-62
770 764 857 859 887 952
] 1607 [1610
96 117 116 99
1022 1010 995
-964 -1194 -1146 -1124
r ii29 I 1202 1 1355 1 1374
68 77 139 116
621 743 884 805
-729 -859 -1020 -926
•> Deficient
70
T. R. WALKER AND D. J. FARRELL
Percentage metabolisability of dietary energy was less (P
Uninfected
Infected 1 2
Values (a—b) in the same column with different superscripts are significantly different (P P > 0-05).
intake of vitamin A-deficient chickens (538 kJ/kgW d) was less (P< 0-01) than that of vitamin A adequate chickens (639 kJ/kgW d) when compared at the same energy balance ( — 256 kj/kg d). Thus the maintenance energy requirement of vitamin A-deficient chickens (882 kJ/kgW d) was less (P0-05) of infection on maintenance energy requirement. Availability of ME (net energy) was apparently not affected by vitamin A deficiency or infection, the mean value being 72%. The relationship between N balance and energy balance was analysed by covariance analysis using values obtained from measurements made on chickens during feeding and on the same chickens during starvation. The N balance of vitamin A-deficient chickens ( — 83 mg/kgW d) was less (PO05) of vitamin A deficiency or infection on the relationship between ME intake (kJ/kgW d) and N balance (mg/kgW d). The average heat productions of chickens during starvation expressed per unit of W and per unit of metabolic size (W 075 ) are shown in Table 6. Starving heat production of infected chickens (619 kJ/kgW d) was greater (P0-05). There was a significant (P
British Poultry Science Publication details, including instructions for authors and subscription information: http://www.tandfonline.com/loi/cbps20
Energy and nitrogen metabolism of diseased chickens: Interaction of Ascaridia galli infestation and vitamin a status T. R. Walker
a b
& D. J. Farrell
a
a
Departments of Agricultural Biology and Biochemistry and Nutrition , University of New England , Armidale, N.S.W., 2351, Australia b
NRM Group , P.O. Box 514, Auckland, New Zealand Published online: 08 Nov 2007.
To cite this article: T. R. Walker & D. J. Farrell (1976) Energy and nitrogen metabolism of diseased chickens: Interaction of Ascaridia galli infestation and vitamin a status, British Poultry Science, 17:1, 63-77, DOI: 10.1080/00071667608416251 To link to this article: http://dx.doi.org/10.1080/00071667608416251
PLEASE SCROLL DOWN FOR ARTICLE Taylor & Francis makes every effort to ensure the accuracy of all the information (the “Content”) contained in the publications on our platform. However, Taylor & Francis, our agents, and our licensors make no representations or warranties whatsoever as to the accuracy, completeness, or suitability for any purpose of the Content. Any opinions and views expressed in this publication are the opinions and views of the authors, and are not the views of or endorsed by Taylor & Francis. The accuracy of the Content should not be relied upon and should be independently verified with primary sources of information. Taylor and Francis shall not be liable for any losses, actions, claims, proceedings, demands, costs, expenses, damages, and other liabilities whatsoever or howsoever caused arising directly or indirectly in connection with, in relation to or arising out of the use of the Content. This article may be used for research, teaching, and private study purposes. Any substantial or systematic reproduction, redistribution, reselling, loan, sub-licensing, systematic supply, or distribution in any form to anyone is expressly forbidden. Terms
Downloaded by [University of Arizona] at 01:15 05 February 2015
& Conditions of access and use can be found at http://www.tandfonline.com/page/ terms-and-conditions
Br. Poult. Sci., 17: 63-77.
1976
Longman: printed in Great Britain
ENERGY AND NITROGEN METABOLISM OF DISEASED CHICKENS: INTERACTION OF ASCARIDIA GALLI INFESTATION AND VITAMIN A STATUS T. R. WALKER1 AND D. J. FARRELL
Downloaded by [University of Arizona] at 01:15 05 February 2015
Departments of Agricultural Biology and Biochemistry and Nutrition, University of New England, Armidale, N.S.W. 2351, Australia Received for publication 10th March 1975
1. Effects of Ascaridia galli infection on the energy and nitrogen (N) metabolism were studied on groups of 5 cross-bred cockerels aged about 5 weeks and given a diet deficient or adequate in vitamin A at two levels of feeding in respiration chambers. 2. Metabolisability of dietary energy was 67% and N retention 33% in infected chickens compared with 71 and 4 1 % respectively, in uninfected chickens. 3. Maintenance energy requirement of vitamin A-deficient birds was 882 kJ/kgW d compared with 998 kJ/kgW d for normal birds. N balance of the deficient chickens was also less when compared at the same energy balance. Infection did not affect maintenance energy requirement nor N balance. 4. Starvation heat production of infected chickens (619 kJ/kgW d) was higher than that of uninfected controls (586 kJ/kgW d). When infection treatments were combined, vitamin A-adequate chickens had a higher heat production (615 kJ/kg d) than the vitamin A-deficient (580 kJ/kgW d). Endogenous N excretion (mg/gW) was less in vitamin A-deficient than in adequate, starved birds. 5. Deficient chickens had undetectable liver reserves of vitamin A and only very low plasma concentrations. There was a difference in the length of larvae (17 d after infection) associated with vitamin A status, and with level of feeding. INTRODUCTION
The margin of profitability in the poultry industry is declining due mainly to increased cost of food ingredients. Thus definition of areas where food utilisation can be improved is of importance. One such area is the intimate relationship between nutrition and disease. It is known that nutritional status affects resistance to 1
Present address: NRM Group, P.O. Box 514, Auckland, New Zealand. 63
Downloaded by [University of Arizona] at 01:15 05 February 2015
64
T. R. WALKER AND D. J. FARRELL
disease, and disease status affects food intake and often its utilisation. However, the mechanisms by which disease affects nutritional status are not well denned. This paper, on nematode infestation, is the first of a series investigating, in chickens, the mode of action of some diseases on nutritional status and on the utilisation of dietary protein and energy. Animals infected with gastro-intestinal nematodes characteristically have impaired productivity associated with inappetance. In addition, digestive function and certain metabolic processes, particularly those related to energy and nitrogen (N) metabolism, may be deranged in nematode-infected ruminants and rats (Symons, 1969; Steel, 1974). Apart from the characteristic reduction in food consumption and growth, there is practically no information on the effects of nematodes on poultry. Ascaridia galli is the most common nematode parasite of poultry. It is most harmful between approximately 10 and 17 d after infection when the developing larvae penetrate the intestinal mucosa (Ackert and Herrick, 1928). Chickens fed on vitamin A-deficient diets harbour larger numbers of larvae which grow more rapidly (Ackbert et al., 1931), compared with birds on adequate diets. It would be anticipated that A. galli infections would not only cause a depression in food consumption but might also modify digestion and absorption of nutrients. Heat production, and therefore availability of metabolisable energy (ME), may also be influenced, since Horak and Clark (1966) reported elevated rectal temperatures in sheep infected with Oesophagostomum columbianum.
The experiments reported here were designed to study, in respiration chambers, the effects of A. galli infection of growing chickens on the ME of the diet, and energy and N balance. Interactions between vitamin A status and infection were also investigated by using adequately nourished and vitamin A-deficient chickens. A preliminary report of some of the work was presented by Farrell and Walker (1974).
MATERIALS AND METHODS
Chickens
One-day-old Australorp x White Leghorn cockerels were housed in electrically heated brooders and offered either a vitamin A-deficient or an adequate mash diet with a ME content of 12-1 ±0-1 MJ/kg, and a crude protein (Nx 6-25) content of 234%. The vitamin A-deficient diet had the following composition (g/kg): wheat, 735; soyabean meal, 130; meat meal, 130; sodium chloride, 2-5; and a vitamin-mineral premix (free of vitamin A) 2*5. The vitamin A-adequate diet had the same composition, supplemented with stabilised beadlets of retinyl esters (Rovimix A-500—Hoffman-La Roche A. Co. Ltd) to provide 3000 fig retinol/kg. At 18 d of age, chickens were intubated per os with either 500 ± 10 infective A. galli eggs suspended in a sugar solution, or with a sugar solution alone for control chickens (Hansen et al., 1954). The infective eggs were produced by taking eggs from mature female worms and incubating them at 30 °C for 25 d (Hansen et al., 1954). Sufficient chickens were reared to enable the five required for each treatment to be selected from approximately 30 chickens. The chickens were wing banded at
65
EFFECTS OF A. GALLI ON METABOLISM
7 d of age and weighed prior to selection. The five chickens chosen for each treatment were selected for uniformity of live-weight (W) such that each of the three calorimeters contained chickens with a similar total weight and range of weights. Experimental plan
Downloaded by [University of Arizona] at 01:15 05 February 2015
Measurements were made on groups of chickens in respiration chambers and offered various amounts of food over a 4- or 5-d period. Details are given in Table 1. Calorimetric measurements were also made on groups of five starved chickens for approximately 22 h following 30 h of food deprivation. These starvation measurements were made on chickens previously used for the feeding experiments and similar measurements were made on other chickens selected from the same groups. Details are given in Table 2. TABLE 1 Vitamin A status, infection treatment, age range, level of food intake and duration of measurement of groups of five fed chickens observed during 4 to 5 consecutive d in respiration chambers
Experiment code
K 1
4
Respiration chamber number 1 2 3
Vitamin A status1 D D
A.galli infection status2 -
D A
1 2 3 1 2 3 1 2 3
Ad libitum 70% of ad libitum
Pair-fed to chamber 1
A
1 2
Level of food intake
Duration of measurement (d)
}
Ad libitum —
Pair-fed to chamber 1
A A A
+ +
Ad libitum 70% of ad libitum
D D A
+ +
Ad libitum 70% of ad libitum
Pair-fed to chamber 1
Age range of chickens3 (d) 28 to 33
36 to 40
}
28 to 33
27 to 32
Pair-fed to chamber 1
A = adequate; D = deficient. + = infected; — = uninfected. Age at commencement and termination of measurements.
Respiration chambers
Three indirect closed-circuit respiration chambers were described by Farrell (1972) and incorporated the minor modifications of Farrell (1974). Experimental procedure
Feeding experiments. Chickens were accustomed to the calorimeters for 2 d prior to the commencement of measurements. The temperature in the respiration chambers was 30+1 °C, and the relative humidity 65 to 75% during the 4 or 5 consecutive days of measurement. Illumination was continous. Chickens were weighed at the commencement and conclusion of each experiment.
66
T. R. WALKER AND D. J. FARRELL
The chambers were opened for approximately 2 h each day during which time the procedures described below were carried out. The commencement and conclusion time for each run was recorded to the nearest minute. Measurements were corrected to 24 h by extrapolation from the actual duration of each run. Weighed amounts of food were offered each day, the restricted groups receiving an amount of food based on 70% of the consumption of the ad libitum group on the previous day. Birds in the control group (Chamber 3) were pair-fed to treated TABLE 2
Downloaded by [University of Arizona] at 01:15 05 February 2015
Prior treatment, vitamin A status, infection treatment and age of groups of Jive chickens obsevedfor 1 d in respiration chambers following 30 h of food deprivation Experiment code
Prior treatment of chickens1
Respiration chamber number n
f
!
ib f L
A
A. galli infection treatment3
Age (d)
D
-
W2
D
_
•
-I
I'
A
-
J
1
U5
p
D
-
^2
D
_
Is
A
A
{j
j
:
}42
A
fl ^2
A A
+ +
"I V35
p
A
+
]
J2 (3 •
A A
+
U6 J
P
D
B
B
f I
Vitamin A status2
\2 B
L36
J
+
1
D
+
p
D
+
1
12
D
+
V-35
\3
A
-
J
.
'
U4
x
A = chickens previously measured during feeding experiments, B = chickens selected from the same groups as A, but not previously measured. 2 A = adequate; D = deficient. 3 + = infected; — = uninfected.
birds in chamber 1. Spilled food was separated from excreta, weighed and the net daily intake calculated. Excreta were removed each day from a weighed polyethylene sheet placed below each cage, and stored at — 15 °C. The weight of traces of excreta remaining on the sheet was determined following air drying. Daily excreta samples were bulked over the 4- or 5-d period of measurement and stored at —15 °C for later analyses.
EFFECTS OF A. GALLI ON METABOLISM
67
Starvation experiments
Similar procedures to those described above for feeding experiments were used for starvation experiments made over approximately 22 h. Endogenous excreta were collected on polyethylene sheets, air dried, weighed and stored for later analyses.
Downloaded by [University of Arizona] at 01:15 05 February 2015
Analytical procedures
At the conclusion of starvation measurements a 2 ml blood sample was taken by cardiac puncture from each chicken, centrifuged and the plasma stored at —15 °C. The chickens were then slaughtered, the livers removed and stored at —15 °C and the intestinal tracts removed for digestion in pepsin solution and subsequent measurement of the number and length of A. galli larvae present, with the aid of a binocular microscope and camera lucida (Sprent et al,, 1967). The vitamin A concentrations of the thawed plasma samples were determined fluorometrically by the method of Kahan (1966) using the modification to extraction suggested by Thompson et al. (1971). Liver vitamin A concentration was determined by direct solvent extraction (Hinds et al., 1968) with acetone: petroleum ether ( 1 : 1 ) followed by spectrophotometric measurement using trichloroacetic acid as the chromogenic agent (Bayfield, 1971). Food and endogenous excreta were finely ground and stored in air-tight containers. Similarly, frozen excreta from the feeding experiments were dried to a constant weight in a freeze-dryer, weighed and finely ground. Representative subsamples were stored in air-tight containers for subsequent energy determination in a adiabatic bomb calorimeter, and N determination using a micro-Kjeldahl procedure. Calculation of results
Heat production was calculated, without correlation for urinary N loss, using the equation of Romijn and Lokhorst (1964). ME concentration of the diet was calculated by the difference in food energy intake and excreta energy output. No N correction factor was applied for the reasons suggested by Vohra (1972). Energy balance was calculated for fed chickens as the difference between ME intake and heat production, and for starved chickens as the summation of heat production and energy content of endogenous excreta, collected over the same time interval. N balance was calculated as the difference between food N and excreta N measured over the same time interval. Biometrical methods
Results from all experiments were pooled for the appropriate analysis unless otherwise indicated. Pooling of results was considered to be valid since all experiments were conducted with cockerels of the same strain obtained from the same hatchery, fed on the same diets, infected with the same worm egg culture and observed at similar ages and live-weights under similar experimental conditions. Results were analysed statistically by conventional use of Students " t" test and analyses of variance and covariance (Snedecor and Cochran, 1967) as appropriate, except for the analysis of N excreted per unit of body weight (W) lost during
Downloaded by [University of Arizona] at 01:15 05 February 2015
O OS
TABLE 3 Weight change, food consumption, metabolisable energy and nitrogen intake, metabolisability of dietary energy, energy balance and nitrogen retention of groups of five chickens observed during 4 to 5 consecutive d of feeding in respiration chambers
Code la
..
Chamber number fl •{ 2 [3
Group live-weight (g). , * > Initial Mean Gain 1130 1254 248 1131 1197 132 1217 1348 263
Gain (%) 21-9 11-7 . 21-6
Food consumption (g/d) 137-8 102-1 144-8
Metabolisability of dietary energy (%) 72-4 70-4 71-0
ME intake (kj/d) 1684 1213 1736
Heat production (kj/d) 1298 1068 1510
Energy balance (kj/d) 386 146 226
, Intake (g/d) 5-16 3-82 5-41
Nitrogen * , Balance Retention (g/d) (%) 2-33 45-3 1-32 34-5 2-32 42-9
H L $ r> g fa > §
fl \2
1346 1463
1409 1536
127 147
9-4 10-0
140-5 132-1
71-5 73-6
1696 1643
1344 1520
352 123
5-25 4-94
2-02 2-12
38-5 42-9
2
f 1 \ 2 [3
1353 1346 1314
1504 1396 1498
302 99 368
22-3 7-4 28-0
199-2 131-3 180-0
65-3 660 71-7
2197 1463 2180
1791 1403 1605
406 61 574
7-45 4-91 6-73
2-83 1-44 2-99
38-0 29-3 44-4
^ g pa
fl ^2 [3
1163 1184 1229
1257 1217 1331
187 66 203
16-1 5-6 16-5
122-6 92-5 132-6
69-2 66-6 70-4
1432 1041 1578
1240 1075 1432
193 -33 145
4-59 3-46 4-96
1-65 1-02 2-13
360 29-5 42-9
r
3
See Table 1 for details of experimental plan.
o
r
69
EFFECTS OF A. GALLI ON METABOLISM
Downloaded by [University of Arizona] at 01:15 05 February 2015
starvation. In this latter statistic, differences in weight loss (g/kg W) between groups of chickens which had been used previously for feeding measurements and those which had not, resulted in variation between replicates of each experiment. This variation was overcome by subtracting the treated group values (chambers 1 and 2) from the control group values (chamber 3) within each experiment. From the data thereby obtained, the main effects of vitamin A deficiency and infection with A. galli and the 2-factor interaction were estimated by orthogonal linear functions of the differences between the treated groups and the control groups. Thus the deficiency effect was determined by adding the transformed means of experiments 1 and 3 and subtracting the mean of experiment 2. A similar combination of transformed means between experiments gave estimates of the infection effect and the 2factor interaction (Snedecor and Cochran, 1967). Independent tests of the main effects and the interation were performed using the pooled within-run variation.
RESULTS
Live-weight change, food consumption, metabolisability of energy, energy balance and N retention of chickens observed during feeding experiments are shown in Tables 3 and 4. Live-weight, heat production, and energy and N balance of chickens observed during starvation experiments are shown in Table 4. These results are pooled between experiments and grouped according to treatment.
FABLE 4 4 status, infection treatment, weight, heat production and energy and W balance of groups of Jive chickens observed during starvation
Infection treatment
Vitamin A status
Adequate Uninfected
*
Deficient
Group liveweight
Group weight loss
(g)
(g) 79 93 105 78 108 105 119
"1244 1306 1359 1451 1519 1629 1679 T1139 1226 •I 1325 1636
[1664 r
Adequate Infected
fl301 J 1502
67 89 86
139 135
Heat production OJ/d)
N
1049
Energy balance (kj/d) -898 -890 -979 -953 -1014 -1076 -1192
balance fe/d) -2-20 -1-92 -2-18 -1-77 -1-95 -2-05 2-23
580 694 761 943 979
-668 -810 -881 -1080 -1119
-1-41 -1-92 -1-72 -2-25 -2-20
805
-2-30 -2-44 -2-13 -1-81 -1-58 -1-75 -1.86 -1-62
770 764 857 859 887 952
] 1607 [1610
96 117 116 99
1022 1010 995
-964 -1194 -1146 -1124
r ii29 I 1202 1 1355 1 1374
68 77 139 116
621 743 884 805
-729 -859 -1020 -926
•> Deficient
70
T. R. WALKER AND D. J. FARRELL
Percentage metabolisability of dietary energy was less (P
Uninfected
Infected 1 2
Values (a—b) in the same column with different superscripts are significantly different (P P > 0-05).
intake of vitamin A-deficient chickens (538 kJ/kgW d) was less (P< 0-01) than that of vitamin A adequate chickens (639 kJ/kgW d) when compared at the same energy balance ( — 256 kj/kg d). Thus the maintenance energy requirement of vitamin A-deficient chickens (882 kJ/kgW d) was less (P0-05) of infection on maintenance energy requirement. Availability of ME (net energy) was apparently not affected by vitamin A deficiency or infection, the mean value being 72%. The relationship between N balance and energy balance was analysed by covariance analysis using values obtained from measurements made on chickens during feeding and on the same chickens during starvation. The N balance of vitamin A-deficient chickens ( — 83 mg/kgW d) was less (PO05) of vitamin A deficiency or infection on the relationship between ME intake (kJ/kgW d) and N balance (mg/kgW d). The average heat productions of chickens during starvation expressed per unit of W and per unit of metabolic size (W 075 ) are shown in Table 6. Starving heat production of infected chickens (619 kJ/kgW d) was greater (P0-05). There was a significant (P
