A. (J. V,I. Fak. Derg. 35 O) : 16-23, 1988
EFFECTS OF FASTING ON PLASMA THYROXINE (T4) LEVELS AND BODY WEIGHT IN CALVES FED WlTH NORMAL AND LOW ENERGY RATlONS'.
Ergun Ş.H.l Özsar S.2
Normal ve düşük enerjili rasyonlarIa beslenen danalarda açlığın plazma tiroksin (T4) düzeyi ve canlı ağırlık üzerine etkisi
Özet: Bu araştırma ile değişik enerji düzeyindeki rasyonla
bes-lenen danalarda açlığın tiroksin metabolizması ve vücut ağırlığı üze-rine etkisi ve meydana gelen metabolik değişikliğin yeniden beslenme ile tekrar normale dönüşü incelenmiştir. Danalar
%
100ve%
50 Yaşama Payı Enerji (YPE) düzeyindeki rasyonlarla iki grupta heslenmişlerdir. Danalar 8 günlük alıştırma dönemini takiben 7 gün aç bırakılmışlardır. Açlık sırasında sadece su verilmiştir. Açlık sonrası 21 gün yeniden aynı rasyonla beslenmişlerdir. Deneme süresince plazma tiroksin miktarlan Radioimmunoassay (RIA) tekniği ile tayin edilmiş, canlı ağırlıkları düzenli olarak kaydedilmiştir.%
100 YPE düzeyinde beslenen danalarda plazma tiroksin konsantrasyonunda açlığın 1. gününde bir düşüş (P <0.05) olmuştur. Diğer taraftan
%
50 YPE düzeyinde beslenendana-larda açlığın 3. gününde bir artış (P <0.05) bulunmuştur. Açlık döne-minde
%
100 ve%
50 ypE düzeyinde beslenen her iki grup danalann canlı ağırlıklarında istatistik bakımdan önemli bir düşüş görülmüştür.Summary: In order to study the effeets of starvation and energy intake on the metabalism of thyroxine and body weight, two groups of ealves were fed wifh normal and law energy rations (100
%
and 50%
of their energy requirement correspondingly). The calves were fasted 7 days following 8 days of feeding and refed with the same rations for 21i Doç. Dr. A.Ü. Veteriner Fakültesi, Biyokimya Bilim Dalı, Ankara.
2 Doç. Dr. Türkiye Atom Enerjisi Kurumu, Lılahan Hayvan Sa~lı~ı Nükleer Araştırma Enstitüsü, Lalahan Ankara.
3 Bu araştırma 1987 Ljubljana. FEBS kongresinde poster olarak sunulmuş ve özeti kongre kitabında yayınlanmıştır.
EFFECTS OF FASTI::-.rC ON PLASMA THYROXINE 17
days. During the experiment the concentrations of plasnıa thyroxine levels were determined by RIA technique and body weights of the animals were recorded regularly. in the 100
%
fed calves, the plasma thyroxine level was decreased on the ist day of fasting (P <0.05). On the other hand in the 50%
fed calves there was an increase (P <0.05) on the 3 rd day of fasting. Fasting had caused a significant drop in the body weight of both groups of animals.Introduction
Thyroxine a hormone of the thyroid glands is the major
regu-gulator of metabolic rate, growth and development of the body. In
addition to these effects, thyroxine has been implicated in the
regu-lation of the glycolytic, gluconeogenic and pentose phosphate
path-ways (4). It is also involved in the regulation of lipid metabolism.
Hyperthroidism causes to increase in the rate of O2 consumption and
this is accompanied by a more oxidized cytosolic redox state and to
increase the rate of fatty acid oxidation (6, 7). Thyroxine metabolism is influenced by changes in the level of energy İntake (2). An İncrease in energy intake for several days results in an increase in the
utiliza-tion rate of T 4 and this inerement depends on both total energy
İn-take and nutrient composition (5).
In some parts of Turkey, feeding Çlfanimals is insufficient.
Un-der the se conditions animal production is affected in the negative
wa¥ wİth respect to metabolic disorders.
Therefore the aim of this work is to evaluate the effect of fasting and refeeding on the plasma T 4levels and body weight in calves fed
with normal and low energy rations.
Materials and Methods
Two groups of calves were used in the experiments. One group
was fed on 100
%
of their maintenance energy requirements andother group was feed on 50
%
of their maintenance energy require-'ments (Tabı e 1, 2, 3).
After an eight day feeding, each group was fas te d for 7 days and
then refed with the same rations for 21 days. During starvation they
18 ş. H. ERGUN - S. ÖZSAR
Table ı.The rations, and the initial body weights and ages of calves fed with 100 %
of their maintenance energy.
Animal Age Weight Rations (kg / day)
No (month) (kg) Commercial feed Fiber
---i 15 184 2 1,0 2 LO 110 1,5 0,5 3 9 135 1,5 1,4 4 7 145 1,5 1,75 5 6 150 1,5 1,9 6 6 110 1,5 0,5 7 113 i 1,0 1,0
Table 2. The rations, and the İnitial body weights and ages of calves fed with 50 % of their maintenanee energy.
Animal Age Weight Rations (kg / day)
i
No (month) (kg) Commercial feed Fiber
---i 15 160 0,5 1,9 2 9 212 1,0 1,1 3 9 171 1,0 0,5 4 8 137 0,5 1,5 5 6 177 0,5 2,1 6 6 125 0,5 1,25 7 5 97 i 0,5 0,7 i 8 3 87 0,5 0,7
Table 3. The amounts of crude feed in the straw and eommercial feed mixture (%), Digestable
i
Dry Crude Cruue Crude Crude Energy" matter Ash Protein Fiber Protein SE! kg
Commercial
Feed 87.1 4.93 j_I6.35
i
9.63 14.10 0.600Straw 95.62 4.8fi 38.97
i
i. 7.9 0.125.SE : Stareh Eq uivalent
i kg. SE: 2.36 KCal Net Energy.
of animals were recorded regularly. The plasma T4 levels were
me-asured before, during and after starvation.
During the experiments blood sa.mples were withdrawn from
jugular veins of the calves, in the mornings. Samples were collected
in heparinized tubes and after the plasma had been separated they
EffECTS OF FASTI:'IG ON PLASMA THYROXINE 19
The concentration öf T4 \vas determined in the plasma by
radio-immunoassay in duplicate, using Amerlex T4 RIA kit. The proportion
of 1251 Thyroxine levels were detected by a Gamma counter.
The results were evaluated by means of "t" test and "t" test for
coupling (10). Such an analysis made it possible to evaluate both .
combined and separate effects ofi fasting and energy intake on thyroid
hormone metabolism and body weight (Table 4, 5).
The 8th day of plasina values were used as controls. Results
The obtained results show that in the i00 ~~fed calves, the plasma thyroxine levels were decreased on the ist day of fasting (P <0.05). But no change was detected on the first day of fasting when energy intake
was law (50 %). On the other hand on the 3rd day, the re was an
increase in T4 levels, but the increase in 50
%
fed calves wassignifi-cant (P <0.05) (Tabı e 4, Fig. I). In both groups body weights were
significantly affected by the fasting (Table 5, Fig. 2). Discussioıı and Conclusioıı
According to Dauncey et al (2), plasma T4 levels increased in
the high inteı.ke of energy but no change was observed when the energy
in.take was law. Although it has bcen shown that high energy intake
is capable of increasing the secI'etion rate of thyroid hormoncs (8),
the present investigation indicated that the re is no significant changes
in plasma T4 levels between i00 ~~ and 50 ~~ fcd cal ves . (TabI e 4,
Fig J). In this study thc values of T4 in both groups retumed slowly
to their normal levcls during refeeding. Dauncey, et al (1) alsa
indi-cated that refeeding itself induced a slow rise in the plasma T4
con-centratian.
Fasting had caused a significant drop in the body weights of.
both groups of animals. During refecding they retumed to their
nonnal values. In the 50
%
fed calves this process was slower (Table5, Fig. 2), O'hea and Lcveille (9) havc found that there was a
dec-rease in body weight of pigs during a fo ur-day fasting and became
normal during refeeding. Fowle and Church (3) indicated that feeding
with poor quality ration and fasting ca.used a 15
%
decrease in theTable 4: Effeet of starvation and refeeding on plasma T. levels (n mol Ilitre; mean ::!: SEM) at different Energy rations. 30 36 122.93 118.25 ::!:12.79 ::!:12.34 124.62 119 ::!:IL. LO ::!:i i .32 After Starvation 23 27 123.18 121.25 ::!:P.74 ::!:12.39 125.56 124.93 ::!:i 1.08 ::!:1l.09 16 20 120 122.31 ::!:J2.50 ::!:12.42 117.12 123.06 ::!:JO.48 ::!:1O.64
ation After Starvation
13 15 16 20 23 27 30 36 42.66 55.81 31. 73 18.36 23.95 43.65 36.73 36.1 ::!:8.63 ::!:iı.14 ::!:5.93 ::!:2.60 ::!:1.72 ::!:9.43 ::!:4.55 ::!:7.63 36.52 56.79 33.7 21.60 23.63 36.54 38.66 30.03 ::!:8.47 ::!:19.04 ::!:8.71 ::!:1.97 ::!:2.41 ::!:5.36 ::!:5.33 ::!:3.66 Starv II 58.07 ::!:7.47 i 58.0 ::!:14.29 vation 13 15 115.12 110.37 ::!:12.33 ::!:12.24 LI 5 .06 110.37 :+:10.41 ::!:1O.43 Star 9 ii 126.75 119.75 ::!:12.98 ::!:12.98 125.93 120.12 ::!:i 1.08 ::!:1O.71 ::!: Hefore Starvation
Table 5: Effeet of starvation and refeeding on body weight (kg; mean ::!: SE M) at different energy rations. Hefore Starvation i 4 8 9 39.68::!: 54.59 24.31 30.01 ::!:5.49 ::!:7.37 ::!:4.66 ::!:3.57 32.77 46.09 40.42 25.74 ::!:4.09 ::!:4.84 ::!:6.81 ::!:4.02 i 4 8 131.18 130.81 131.31 ::!:13.07 ::!:12.92 ::!:13.19 129.93 130.31 130.87 ::!:10.99 ::!:11.23 11.19 maintenance vel (n ~8) f maintenanee vel (n =7) ime (day) maintenance vel (n=8) f maintenanee vel (n=7) me (day) -Ti 50 % of energy le 100 % o energy le T 50 % of energy le 100 % o energy le
EFFECTS OF FASTlNG ON PLASMA THYROXINE 21 20.00 B.5.
.Q
S••
A. S.•
";' Ö E 6QOO c i-~ <ıl E OJ! <ılo:
f',, , 10.00 O 5 ro 15 20 25 30 35 lıme(day)Figure ı.Effect of starvation and refeeding on plasma Thyroxine (T4) levels at different energy ratİons. o-o: 100 % of maintenanee energy level; e-.: 50 %of maintenance
encrgy level; B.S: Before starvation; S: Starvation; A.S: After starvation.
Şekil
ı.
Farklı enerji düzeylerinde, açlık ve yeniden beslenmenin plazma Tiroksİn (T4) düzeyleri üzerine etkisi. o-o: % 100 Yaşama Payı Enerji (YPE) düzeyi, e-o:: % 50YPE düzeyi; B.S: Açlık öncesi; s: Açlık; A.S: Açlık sonrası.
In candusian, in both groups, body weights were affected
sig-nificantly during fasting (P <0.00 i) but T4 levels did not change at
the same ratc as the body weights. The unaltered T4 values in each
energy ratian might be due to the variations in the ages and body
22 ş. H. ERGU:\ S. OZSAR B c J. 150 ol x :c ol :..'..0 cı. ~ 130
..
---170 110 ~.
.
r....
- -
•.
-
_-
---.---
~'
",,.---
--"-"
i • i i , i , i 100 o LO 1~.
20 , 2') :ıO 35 trrrıp(ddY)Figure 2. Effeet of stal'yation and refecding on budy ıı'cight at diffcrenı energy rations. o-o: 100%of Maintenance el1ergy leye!; o-e 50 %of maintenancc encrgy leyel; BS:
Bcfore staryation; S: Starvation: A.S: After stal'yation.
Şekil 2. Farklı enerji düzeylerinde, açlık ve yeniden beslenmenin canlı ağırlık üzerine etkisi. o-o: ?{, 100 Yaşama Payı Enerji (YPE) düzeyi; e,-e; %50 YPE düzeyi; B.S:
Açlık öncesi; S: Açlık; A.S: Açlık sonrası.
I{efcrcnce~
J. Dauncey, M.J., ln::ıram, D.L, Macari, M. and Ranısdcn, D.B. (l982). Jııcrease iıı p/asma COlı('('lıfl'(lfiolı(Jf fhyroid horll/oıı('s iıı p~f!/efs after a mea/. J. Physio1., 327,
90-91.
2. Dauncey, M.J.; Ranısden, D.B.; Kapadi, A.L; Macari, M. and Ingram, D.L. 0983): Jııerease iıı p/asma coııeellfrafior1s oj 3.5', 3'- Triiodof'ıyrioııiııe Q'ıd thyoxiııe affer o mea/ aııd its depelidelice 011Eııergy illfake. Horm. MetaboL. Res. 15. 499-502.
3. Fowle, K.E., Church, D.C. (1973): Effeet of a I/llfriıioııa//y poor raf iOlI. s/ıorf ferm fastiııg aııd refeedflıg 011goafs. Anıer. J. VeL Res .. 34, 849-852.
4. Glock G.E. and Melean, P. Whitchead, J.K. (l956). Poı/urays of f[/ııwse cala bolisııı iıı raf lirer iıı A/loxmı Di"beles aııd Hyperfhyroidisll/. Biochem J. 63. 520-524.
EFFECTS OF FASTII'\G 0;-'; PLASMA TI-JYRO~ıNE 23
:ı. Ingram, D.L., Daııncey, M.J., Barrand, M.A., Callingham, B.A. (i9XO). Varialioııs in plasma catecholamiııes iııthe youlig pig iıırespolise to extremes of amhieııt tempera-ture compared witl, excercise aııd feediııg. Iıı catecllOlamiııes aııd stress. pp. 273-278, Eds. E. Usdin, R. Kvctnansky and 1..1.Kopin, Amsterdam Elsevicr, North Holland.
6. Laker Mary E. and Maye~ Peter A. (1978). Thyroid status oııd hepmiclipid metabolism iıı the rat. Biochem. Sac. Transanct., 6, 584-585.
7. Laker, M.E. and Maycs, P.A. (198ı).E/fect of hyperhyroidism aııd hypothyroidisııı 011
lipid and charbohydrate metabolis/ıı or the peı/i/sed rat Iil'er. Bioclıcm J. 196. 247-255. 8. Macar', M., Dauncey, M.J., Ramsden, D.B., and Ingram, D.L. (1983). Thyroid
hor-hormone metabolism aJier acc!imati;:aTiolı lo a wayııı or cold temperaTure Illıder coııdi-tioııs of MgI! or Law eııergy intake. Oııart, J. Exp. Physiol., 68,709-.718.
9. O'hea, E.K. and Le\'eille, G.A.(i969). Iııfluel/ce ofJiıstiııg aııd refeediıı:;011 lipogcııcsis
and eıızymatic activity of pig adipose tissue . .I. Nutr., 99, 345-352.
LO. Sokal, R.R. and Rohlf F.J. (1969). "Biometry". The priııciples orpractice ofstatisıics in biologiml research. W.H. Freeman and Company. San Francisco.
