Light-dark variations of oxygen consumption and subcutaneous temperature in young gallus domesticus: Influence of ambient temperature and depilation

J. therm. Biol. Vol. 10, No. 1, pp. 13-20, 1985

0306-4565/85 53.00+0.00 Copyright L~ 1985 Pergamon Press Ltd

Printed in Great Britain. All rights reserved

L I G H T - D A R K VARIATIONS OF OXYGEN CONSUMPTION A N D SUBCUTANEOUS T E M P E R A T U R E IN Y O U N G GALLUS DOMESTICUS: I N F L U E N C E OF AMBIENT T E M P E R A T U R E A N D DEPILATION H. MICHEl.S, M. HERREMANS and E. DECUYPERE Laboratory for Eco-Physiology of Domestic Animals, Catholic University of Louvain. Kardinaal Mercierlaan 92, 3030 Heverlee, Belgium (Received 7 July 1984)

A~tract--1. With lower ambient temperatures (Ta): (a) subcutaneous temperature (T,,) was subject to large individual variations and to a higher variation of instability between depilated chicks; and (b) depilated chicks compared to controls, showed a larger increase in O: consumption; during darkness their increase in T~ was lower, but during light hours the fall in T~ was the same. 2. Lower light-dark variations of T~ and O2 consumption at lower Ta in young chicks can be put in parallel with lower circadian variations at higher T~'s, as found in adult animals. Key Word Index--Bird; Gallus domesticus; thermoregulation; 02 consumption; circadian variations;

light-dark variations; depilation; thermal conductance; body temperature; metabolic heat production.

INTRODUCTION

Very few data are available on circadian variations of metabolic parameters in young, growing chicks. Lamoreux and Hutt (1939) showed that in young (14-day-old) chicks diurnal variation of rectal temperature was much the same as that found by other authors in adult domestic fowls. MacLeod et aL 0980) found that the relative amplitude of the decrease in heat production during the dark phase was about twice as great during the 10 h of darkness given to adult hens as it was during the 1 h period of darkness experienced by the young (12-day-old) chicks, but they did not discuss the possibility of an effect from age, weight or reproduction. This study was aimed to examine light-dark (L/D) variations in 02 consumption (Vo2) and subcutaneous temperature (T~), and the relationship between both as a function of ambient temperature (Ta) and body insulation, in young domestic fowls.

MATERIALS AND METHODS

Eggs taken from a broiler (Hibro) and a laying (Hisex) hybrid population, were subjected to standard incubation conditions at 37.8°C (Michels et al., 1974). From hatching onward chicks were kept in a well-ventilated (5000 m 3 h -1 ), air-conditioned animal house at a temperature of 25 _ l°C. Light was given at an intensity of about 75 Ix from 7 a.m. to 7 p.m. At Day 12 post-hatching a temperature sensor in platina wire (Pt-100) was inserted under the skin on the back near the scapular region in 14 chicks, chosen at Abbreviations: Vo2, 02 consumption; T,~, subcutaneous tem-

perature; T,, ambient temperature; L, light; D, dark; N, depilated (naked); C, control; SD, standard deviation.

random, out of each group. Afterwards they were caged individually in Plexiglas boxes to prevent huddling and the next night these cages were put in two respiration chambers, each chamber containing 14 chicks, 7 from each group. All chicks from Chamber 1 had been depilated [naked (N) chicks] on Day 7 by the topical application of calcium thioglycolate (Wekstein and Zolman, 1971). From Day 13.5 ( = Night 13) up to Day 21.5 the animals were subjected to the following T,: 30°C (3 nights, 3 days); 20°C (2 nights, 2 days); 15°C (1 night); 10°C (3 days, 2 nights); 5°C (1 night). The r.h. was kept constant at 60%. A light schedule of 12L/12D was followed with a light intensity of about 75 Ix, except when care had to be given just outside the standard scheme. Feed and water were given ad libitum. The chicks were weighed after exposure to each physical environment. Vo2 was measured continuously (Geers et al., 1978a, b). The mean chick body weight (kg) of each group was calculated and raised to the power of 3/4 to obtain the mean chick metabolic body size. Vo: was expressed as the volume (STPD)/unit metabolic body size per h. T~ was measured continuously with a frequency varying between a minimum of 6 temperatures per chick every 1.5 h during the day and a maximum of 25 temperatures per chick every 1.5 h at night. This variation was generated by the software of the directing microprocessor (Rockwell AIM 65) which, in controlling the similitude of measurements (excluding aberrant values, due to interference or induction on the electric current, most likely to happen during the day), required a different measuring rate for night and day. A precision of 0.08°C was obtained after adjustment for the divergent deviation when Ta rose, by corrections obtained from a separate regression for each Pt-100; regressions were pointed out after extensive gauging in water. Data on Vo: and T,~ were 13

H. M[CHELSet al.

14

calculated for every subperiod of 1.5 h during light or dark. Only those periods with a sufficient number of undisturbed figures for both criteria were taken into account. Within each of the 16 diurnal subperiods all 6-23 individual T~ were taken together into a mean value and a standard deviation, both being used in our calculations as new criteria without degrees of freedom. Within each treatment [7, and depilated/ control (N/C)] one 24 h period (L and D) was chosen for which all 16 subperiods were analysed by a paired t-test with the standard deviations of differences pooled for all combinations of the 16 periods. In order to overcome the statistical risks related to the total number of tests (120), the significance limit was fixed at P ~<0.005 (see Fig. 1). Mean values and standard deviations from within the 16 diurnal subperiods were taken together and compared in a three-way analysis of variance (L/D, T~, N/C). For Vo+ only a lumped mean of the 14 individuals in eaclq respiration chamber was available; a similar three-way ANOVA was applied as for

RESULTS

Diurnal rhythms of T~ (Figs I and 3) According to the paired t-analysis most data on L/D variations were statistically significant in C and N chicks at all T~. Morning peaks were only statistically higher than the other L values in a few cases, whereas evening peaks were significant at higher levels. Initial D values were generally statistically higher than midnight values. A significant anticipatory increase as a response to the D/L interface was seen. Because of the latter phenomena, the extreme D values came statistically within the range of L levels at 10°C. This was partly due to an increase of inter-individual variations (Fig. 1). According to the ANOVA, very significant differences were found in mean values between L and D (P <<< 0.00001), T~ (P < 0.00001), N and C (P = 0.00057), with all i,~teractions being significant (P < 0.00001). At 30~C no differences were present between C and N chicks in both L and D conditions, while at 10°C in D hours C chicks had a significantly higher T~ than N birds (P ~<0.001), indicating a

T~. N CHICKS

C CHICKS

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~,

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~o

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Fig. I. Circadian variation in T~ (mean and standard error of mean) as a function of T, (A = 30 C, B = 20°C, C = 10°C). Within the same treatment, different letters indieate differences at the 0.5'~i, level. Connected dots represent consecutive D and L periods for paired t-analysis. Isolated dots represent replicated values.

15

Variations in 02 consumption and subcutaneous temperature in young chicks N CHICKS

A

C CHICKS

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Fig. 2. Circadian variation in Vo2 as a function of T, (A = 30°C, B = 20°C, C = 10°C). Connected dots represent consecutive D and L periods. Isolated dots represent replicated values. higher increase of T= in C chicks in response to lower 7",. Differences between L and D values sharply decreased in the C group at that T, (P ~< 0.05), whereas in the N group they were still present (P ~<0.0001) (Appendix 1, Table A). Significant differences in mean values between C and N birds were seen during the D period (P ~<0.01), but not during L hours (Appendix 1, Table C). The increase with lower Ta during D hours was statistically more pronounced than the decrease in the L hours, for C and N groups taken together (Fig. 3, Appendix l, Table B). Differences in intra-individual SD's of T~ were generally significant between N and C (P <<0.00001), T, (P <<0.00001) and less so between L and D (P = 0.00085), with all interactions being significant (P < 0.0001). With lower T., higher intra-individual variations were found in N birds, but the increase at 20°C was only significant during D hours. In C birds intra-individual SD's were at the same level at different T., except at 10°C in D hours where they were higher. Intra-individual SD's in N and C chicks were at the same level at 30°C, and at 20°C during L hours. A higher intra-individual SD in the N group was associated with a higher variation of this SD, indicating a higher variation of instability between individuals (Table 1, Appendix 2). This means that T=, as a characteristic of homeothermy, was subject to large intra-individual oscil-

lations, and an inter-individual variability in this respect, in N birds at lower T., with a higher instability in D hours from 20°C onward. 410 o2 02

A2

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ro(-C ) Fig. 3. Influence of T= on T,, in N ( A A - - - ) and C (O © ) chicks during L (A O) and D (A 0 ) phases. Digits indicate first or second day of treatment.

16

H. MICHELS e t al.

Table 1. Mean intra-individual variation IXsD) of 7"~ I C). deviation of this variation between individuals tSDsD ~ and the number oi" SD'~ used in analysis (n) at different Ti's and treatments N chwks

D phase (zC) 30 20 10 5

"~SD

SDsD

0.1240 + 0.0664 0.2068 ± 0,1206 0.2144 ± 0.1095 0.2252 +_0.1859

( t'hick~ L phase

n 224 109 88 72

~'sl)

SDsD

0.1300 + 0.0691 0.1465 _~ 0.068 0.2067±0.1544

Diurnal rhythms of 1%: (Figs 2 and 4) According to the ANOVA, very significant differences in mean values were found between L and D (P <<< 0.00001), T~(P <<<0.000011, N and C (P <<< 0.00001) with all interactions being significant (P < 0.00001). Differences between C and N birds at 30°C were highly significant (P ~< 0.0001), but not between L values of C chickens and D values of N birds. Differences between values at 30, 20 and 10°C were significant (P ~<0.00011, as were differences between L values of C chicks and D values of N birds at 10°C (P ~<0.0001), indicating therewith a higher increase of Vo: in the latter with lower 7~,. For both groups, differences between L and D were statistically significant at 30°C (P ~<0.0001), but not at 10°C and not even at 2 0 C in the C group (Appendix 3). Relationship between the average Vo,- and T~ (Figs 3-5) 1. Different changes in L and D values were found as a function of lowering T,,. For Vo, there was a differential increase, except for D values at 5'~C in N birds, whereas T~ showed a reverse pattern between L and D, except for D values at 5"C in C birds (Figs 3 and 4). 2. Different changes were found as a function of body insulation. Vo, was higher in N birds for every experimental condition, whereas T~ was significantly lower during D, except at 3OC. With lower T~, N birds showed a higher increase of Vo, than C chicks, a lower increase of T~ during D but an equal decrease during L time (Figs 3 and 4). 3. A varying relationship between Vo_~and T~¢ was shown as a function of time of day and T,. At 3 0 C regression lines representing D values had steeper slopes than the regression lines representing L values, the difference being only pronounced in C birds. At lower T~, regression lines representing L values showed a reversed relationship in comparison to D values, as illustrated for C birds at 1 0 C (Fig. 5).

D phase n 195 192 173

XsD

L phase

SDsD

i1

0.1150 - (I.(1916 (/.1285 _~ 0.0621 0.1856 ~_ 0.0857 0.1422 --_0.0647

192 8O b;~ 99

'(~t,

SDsD

0.1117 + 0.0607 O. 1(125 __+0.(t662 0.1261 ~- 0.0693

tl 16(I

76 15q

As to the dependence of bod~ temperatures and day-night differences of body temperatures on T~,, the results of Graf (1978, 19801 show that the amplitude of the L/D period increased with falling 7 d. This was due to a slight increase of spinal temperature with falling 7~, during the L phase and a significant decrease with T, during the D phase. Mean skin temperature decreased with falling Td both in the L and D phase. Our results show a decreasing amplitude of the L/D period with falling 7~. due to a decrease of T~ during the L phase and an increase during the D phase. These contradictory results wilt be discussed further, but since changes in a reverse direction during L and D hours were found in both experiments they support the hypothesis that our measurements of T~ in the scapular region can be considered equivalent to those of spinal, i.e. deepbody temperature. This is also supported by Misson (1978) who proved that intramuscular back temperature in tissues overlying the spinal cord gives an excellent reflection of body core temperature in the domestic fowl. The important intra- and inter-individual variability of T,,, as found in C and N birds at lower T~ in the D phase, was not discussed by the authors mentioned up to now who were working on circadian rhythms in the domestic fowl. Only Berman and Meltzer (t978) found a large inter-individual vari-

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DISCUSSION

Our data on T~ are in general agreement with those on adult hens under L/D cycles. An anticipatory increase of T~ as a response to the D/L interface was found in most cases and was also seen by Cain and Wilson (1974). Morning and evening peaks of T,~ were found, and are in agreement with data on heat production obtained by Lundy et al. (19781 and by Klandorf et al. (1981). Morning and evening peaks of body temperature were also found by Graf (1978, 1980) in the adult pigeon.

I

I

1

5

10

20

30

To{°C> Fig. 4. Influence o f T, o n Vo: in N ( A / ~ ) and C (OC)--) chicks during L (/XO) and D (AQ) phases. D i g i t s i n d i c a t e first o r s e c o n d d a y o f t r e a t m e n t .

Variations in 02 consumption and subcutaneous temperature in young chicks (A)

I

4 i

IS I

I 4o

T

(B)

41

I

2

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40

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T~¢(*C) Fig. 5. Relation between T,~ and Vo2 during D ( e ) and L (O) phases at 30°C (A) and 10°C (B) in C chicks. Digits indicate consecutive l.Sh periods. (A) D, y = - 5 2 . 7 + 1.4 x (r =0.87); L, y = - 11.2+0.3 x (r =0.19). (B) D, y = - 107.5 + 2.8 x (r = 0.93); L, y = 9.2 - 0.1 x (r = 0.32).

ation under constant lighting, underlining the entraining influence of the L/D cycle on the daily rhythm of metabolic rate. Inter-individual variation with respect to the circadian rhythms of heat production and body temperature as a function of Ta, was mentioned in the pigeon (Graf, 1978). Our data on V~ are in general agreement with those on growing and laying adult fowls. Significant differences in mean values were found between L and D phases. Morning peaks, night drops and anticipatory increases as a response to the L/D interface may be suggested from Fig. 2. An anticipatory increase of heat production was also found by Berman and Meltzer (1978) in adult hens. Decreasing differences in T~ and Vo: between L and D periods with lower Ta, as found in the present experiment, are opposed to the increased amplitude of the L/D period by lowering 7", in the adult pigeon, as found by Graf (1978, 1980). Klandorf et al. (1981) found lower differences in heat production between L and D periods in the adult hen at the higher T~ of 32°C. Effects of age and body weight on the thermoneutral temperature zone, previously shown by Barott and Pringle (1946) and Romijn (1950), can probably be included here. According to Herreid and Kessel (1967), heat loss in defeathered birds is 2-3 times higher than in intact birds. In our birds, depilation probably had its full action, since chicks were caged individually. The importance of this was shown by Wathes and Clark TB

I01

B

17

(1981) who found that broiler chicks spent approx. 67~o of their time in a cluster, in which their normal heat losses were between 30 and 60°.o of those of an individual bird. Body plus plumage resistance was found to be constant up to 30 days post-hatching. Therefore an age effect can probably be excluded from our own data. at least in C birds. C and N chicks at 30°C were probably at or below their thermoneutral temperature zone, according to data from Kleiber and Winchester (1933), Barott and Pringle (1946), Romijn (1950), Freeman (1963), Misson (1976) and Decuypere (1979). These chicks showed L/D variation in Vo, and T~, as was also found in adult horned larks (Trost, 1972) and adult pigeons (Graf, 1980) at decreasing Z~. N chicks had a higher metabolic rate at 30°C than C chicks, probably in order to compensate for a higher conductance. However, data in both groups indicate the existence of circadian variations in thermal conductance, differences between L and D only becoming smaller when conductance increases at higher T,~, above the zone of metabolic thermoneutrality (Aschoff, 1981). Since Vo, increased at 20 and 10°C in C and N chicks, it can be concluded that both groups were below their thermoneutrai temperature zone at these T~. In these colder environments conductance probably decreased as a consequence of persistent vasoconstriction, as postulated by G r a f (1980). According to Richards (1971), this vasomotor activity should take place particularly in the naked extremities, since the thermal circulation index at the feathered skin sites did not change as a result of changes in the thermal environment. This can explain why the increase in Vo. was higher in our depilated animals, suggesting an increased conductance, as can be concluded from Herreid and Kessel's (1967) data. But the question arises whether vasomotor activity in the depilated skin cannot be changed by varying Td. Trost (1972) found that conductance decreased with decreased T~, but at a faster rate during the night than during the day. According to Aschoff (1981), minimal conductance is subject to circadian variations in both mammals and birds, the functional significance of this being to promote heat dissipation during the activity time when the basal metabolism is set at a higher level, and to conserve heat during the rest time when metabolism is low. However, the increase in Vo,, with a probable concomitant and permanent vasoconstriction in the naked extremities at least, was probably at the origin of lower L/D variations in Vo, and T~ at the lower T,s of 20 and 10°C. Lower L/D variations in young chicks in these conditions can then be put in parallel with lower circadian variations at higher Ta as found by Trost (1972) in horned larks and by G r a f (1978, 1980) in adult pigeons. In this way higher conductance found at higher Ta (Trost, 1972) and lower conductance at lower Zd would have the same effect on circadian variations. It is however not clear to what degree a varying conductance can explain the varying relationships between Vo2 and T~, as a function of time of day, in C and N chickens and at varying T,. At 30°C our results are in agreement with those obtained by Aschoff and Pohl (1970) in man and bramblings.

H. MICHELS el al.

18

The question can be posed whether short-term effects, as found in this experiment, can be followed by long-term effects on circadian variations in metabolic rate and body temperature, taking into account the effects from seasonal acclimatization and incubation temperatures on the thermoneutral temperature zone, Vo,., metabolic heat production and energy balance, as shown by Arieli et aL 1979, 1980), Decuypere (1979), Michels et al. (1980), Geers (1981), Geers and Michels (1982) and Geers et al. (1983). The energy sparing effect of circadian cycles, allowing the fowl to evade the additional energy cost of increasing its metabolic rate in response to the cold of the night, as already underlined by G r a f (1978) and Arieli et al. (1979), should be stressed here. To what degree circadian variations in body temperature and metabolic rate can be influenced together or separately in long-term experiments, is a final question. F r o m their review on man and dayactive birds, Aschoff et al. (1974) concluded that the 24h rhythm of deep-body temperature is the consequence of rhythms in heat loss and in heat production, G r a f (1980) concluded that the described diurnal variations in the pigeon are in agreement with the concept of an active generation of the body temperature rhythm by the thermoregulatory system. Our data indicate different changes for both variables as a function of T~, but the question whether they are based on a c o m m o n thermoregnlatory process demands further research and can perhaps be elucidated more thoroughly in a long-term experiment.

SUMMARY

Subcutaneous temperature (T~) and 02 consumption (VoO were measured continuously in control (C) and depilated (N) young chicks, during light and dark ( 1 2 L / 1 2 D ) hours and at different ambient temperatures (T~ = 5, 10, 15, 20 and 3 0 C ) . Significant differences in mean values were found between treatments, with all interactions being significant. The increase of T~ with lower T~ during D hours was statistically more pronounced than the decrease during L hours, with indications for a higher increase in the C group during D hours. At 10"C, differences in T~ between L and D values were sharply decreased in the C group but not in the N group. In both groups superior D values were statistically within the range of L values at that T,~. This was partly due to an increase in inter-individual variation. A higher intraindividual SD in the N group at lower 7~ was associated with a higher variation of this SD, indicating a higher variation of instability between individuals. Differences between values of Vo, at 30, 20 and 10°C were significant, with indications for a higher increase of Vo, in N chicks; differences between L and D values were no more significant at 10~C in both groups (N and C). Lower L / D variations for Vo. and 7~ at lower 7~, in this experiment can probably be put in parallel with lower circadian variations at higher T,, as found in adult animals of other species. The question arises whether short-term effects, as found in this experi-

ment, can be followed by long-term effects on T,~ and 1~o~, as related or independent criteria. Acknowledgement--E. Decuypere was supported by the Nationaal Fonds voor Wetenschappelijk Onderzoek (NFWO). REFERENCES

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V a r i a t i o n s in 0 2 c o n s u m p t i o n a n d subcutaneous t e m p e r a t u r e in y o u n g c h i c k s l a t i o n in b a b y chicks. Proc. Soc. exp. Biol. Med. 31, 158-159. L a m o r e u x W. F. a n d H u t t F. B. (1939) V a r i a b i l i t y o f b o d y t e m p e r a t u r e in the n o r m a l c h i c k . Pouh. Sci. 15, 7 0 - 7 5 . L u n d y H . , M a c L e o d M. G . a n d J e w i t t T. R. (1978) A n a u t o m a t e d m u l t i c a l o r i m e t e r system: p r e l i m i n a r y experim e n t s o n l a y i n g hens. Br. Poult. Sci. 19, 173-186. M a c L e o d M. G . , Tullett S. G . a n d J e w i t t T. R. 0 9 8 0 ) C i r c a d i a n v a r i a t i o n in the m e t a b o l i c r a t e o f g r o w i n g c h i c k e n s a n d l a y i n g h e n s o f a b r o i l e r strain. Br. Poult. Sci. 21, 155-159. M i c h e l s H., G e e r s R. a n d M u a m b i S. (1974) T h e effect o f i n c u b a t i o n t e m p e r a t u r e o n p r e - a n d p o s t h a t c h i n g develo p m e n t in c h i c k e n s . Br. Poult. Sci. 15, 5 1 7 - 5 2 3 . M i c h e l s H . , D e c u y p e r e E. a n d G e e r s R. (1980) P r o d u c t i o n a n d p h y s i o l o g i c a l c r i t e r i a in l a y i n g R . I . R . - h e n s in r e l a t i o n to p r e n a t a l a n d p o s t n a t a l e n v i r o n m e n t a l t e m p e r a t u r e s . In Energy Metabolism ( E d i t e d b y M o u n t L. E.). pp. 3 7 1 - 3 7 5 . B u t t e r w o r t h s , L o n d o n .

19

M i s s o n B. H . (1976) T h e effects o f t e m p e r a t u r e a n d relative h u m i d i t y o n the t h e r m o r e g u l a t o r y r e s p o n s e s o f g r o u p e d a n d i s o l a t e d n e o n a t e chicks, d. agr&. Sci. 86, 35--43. M i s s o n B. H . (1978) A n o t e o n the m e a s u r e m e n t o f b o d y t e m p e r a t u r e in Gallus domesticus. J. therm. Biol. 3, 175-176. R i c h a r d s S. A. (1971) T h e significance o f c h a n g e s in the t e m p e r a t u r e o f the skin a n d b o d y c o r e o f the c h i c k e n in the r e g u l a t i o n o f h e a t loss. J. Ph.rsiol., Lond. 216, 1-10, R o m i j n G . (1950) S t o f w i s s e l i n g s o n d e r z o e k bij de kip. P r o e ven m e t N o o r d - H o l l a n d s e B l a u w e n . Tijdschr. Diergeneesk. 75, 7 1 9 - 7 4 6 . T r o s t C. H . (1972) A d a p t a t i o n s o f h o r n e d l a r k s (Eremophila alpestris) to h o t e n v i r o n m e n t s . Auk 89, 5 0 6 - 5 2 7 . W a t h e s C. a n d C l a r k J. (1981) Sensible h e a t t r a n s f e r f r o m the fowl: r a d i a t i v e a n d c o n v e c t i v e h e a t losses f r o m a flock o f b r o i l e r c h i c k e n s . Br. Poult. Sci. 22, 185-196. W e k s t e i n D. R. a n d Z o l m a n J. F. (1971) C o l d stress r e g u l a t i o n in y o u n g chickens. Poult. Sci. 50, 5 6 - 6 1 .

APPENDIX

1

Subcutaneous Temperature (Ts~) (A) Full contrasts

30 ND 30 20 20 10 10

NL ND NL ND NL

30 CD 30 CL

20 CD 20 CL 10 CD 10 CL

10 CL

10 CD

20 CL

20 CD

30 CL

30 CD

10 NL

10 ND

20 NL

20 N D

**** NS **** NS **** NS

**** * ** ** *** NS

**** NS **** NS **** NS

NS **** NS **** NS ***

**** NS **** NS **** **

NS **** NS **** NS ****

**** NS **** NS

NS **** NS ****

**** NS **** --

NS **** --

**** NS **** NS *

**** **** NS NS

**** NS ***

NS **** --

30 NL

30 N D m

Abbreviations and significance levels: N = depilated chicks; C = c o n t r o l chicks; D = dark; L = light; *P ~< 0.05; * * P < 0.01; * * * P ~< 0.001; * * * * P ~< 0.0001; NS = not significant. (B) Partial contrasts

30 30 20 20 10

10 D **** **** **** NS ****

L D L D L

l0 D

10 L ** **** NS **** --

20 D **** ** **** --

20 L NS **** --

(C) Partial contrasts 30 D **** __

30 L --

ND NL CD CL

--

CL

CD

NL

ND

**** NS **** --

** **** --

**** --

__

Abbreviations etc. as in Table A.

Abbreviations etc. as in Table A. APPENDIX

2

lntra-individual SD r~ : full contrasts

30 30 20 20 10 10 5

ND NL ND NL ND NL ND

30 CD

30 CL 20 CD 20 CL

I0 CD 10 CL 5 CD

5 CD NS NS * NS i ** ** ** NS NS NS NS NS NS

10 CL 10CD 20 CL 20 CD 30 CL 30 CD 5 N D 10 NL 10 ND 20 NL 20 N D 30 N L 30 N D NS NS • *** NS • *** • *** • ***

* NS NS NS MS NS NS

NS NS **** NS **** **** ****

NS NS ** NS *** *** ***

NS NS **** NS **** **** ****

NS NS NS NS

** *** NS **

NS NS NS --

NS NS --

NS --

Abbreviations etc. as in Appendix 1, Table A.

NS

****

****

****

NS

****

NS

****

****

****

NS

****

**** NS **** ****

NS *** NS NS

NS *** NS --

NS ** --

** __

--

NS

--

20

H.

MICHELS

et al.

APPENDIX 3 0 2 C o n s u m p t i o n ( ['o,_ ) ." ]idl contrasts

30 N D

-

30 N L 20 N D 20 N L 10 N D 10 N L 30 30 20 20 10 10

CD CL CD CL CD CL

Abbreviations

10 C L

10 C D

20 C L

20 C D

**** **** NS **** **** ****

**** **** NS **** **** ****

**** ** NS **** **** ****

**** NS * **** **** ****

• ***

****

****

****

**** * NS NS

**** NS NS --

**** NS --

**** -

etc. as in A p p e n d i x

30 CL

30 C D

10 N L .

N

.

S

10 N D .

.

NS ****

**** ****

**** ****

**** ****

****

****

****

**

****

****

****

****

1. T a b l e A .

NS

20 NL .

**** ***

20 N D .

.

****

30 N L

30 N D