Abstract
Food and water consumption, estrus cycle length and regularity, mating rate, number of corpora lutea and morulae and early blastocytes on day 4 of pregnancy, were studied in a group of heat-acclimated female rats (35 ± 1°C). The results were compared with those of rats maintained at control temperature (22 ± 2°C). The heat-acclimated animals consumed the same quantity of food per 100 g of body weight as the controls. Water consumption in the heat was higher. Duration of estrus cycle was prolonged by 24% (p < 0.001), while the number of days associated with proestrus and estrus smears during the experimental period was smaller by 14% and 20% (p < 0.001), respectively. The number of days associated with metestrus and diestrus smears was larger by 25% and 24% (p < 0.001) respectively, in the heat-acclimated group as compared with controls. Mating rate was 47% lower (p < 0.01) in the 35°C group. There was no difference between the two groups in the number of corpora lutea, although the number of 4-day old morulae and early blastocysts in the heat-acclimated rats was 25% smaller (p < 0.01) than that of the control animals.
Zusammenfassung
Der Futter- und Wasserkonsum, die Länge und Regelmässigkeit des Oestruszyklus, die Aufnahmerate, die Anzahl Corpora Lutea und Blastozysten am 4. Trächtigkeitstage wurden in einer Gruppe Ratten bestimmt, die mehrere Wochen bei 35 ± 1°C gehalten worden waren. Die Kontrolltiere lebten bei 22 ± 2°C. In der Hitze war das Wachstum verzögert, der relative Futterkonsum (g/100 g Kp. Gew.) war aber bei beiden Gruppen gleich. Der Wasserkonsum war erhöht. Ebenso war der Oestruszyklus um 24% verlängert (p < 0,001). Während die Anzahl Tage mit Prooestrus and Oestrus um 14% bzw. 20% vermindert war, waren die mit Metoestrus und Dioestrus Zeichen vermehrt (p < 0,001). Die Anzahl Corpora Lutea war in beiden Gruppen gleich, dagegen war die Anzahl Blastozysten bei den Hitze-Ratten 25% geringer als bei den Kontrollen.
Resume
Des femelles de rats ont été acclimatées à la chaleur (35 ± 1°C). On a ensuite contrôlé leur consommation en eau et en nourriture, la longueur et la régularité de leur cycle menstruel, leur taux d'assimilation ainsi que le nombre de corpora lutea, de morulae et de blastocystes au 4ème jour de gestation. Les chiffres ainsi obtenus ont été comparés à ceux de rats maintenus à une température de contrôle (22 ± 2°C). Les rats acclimatés au chaud ont consommé autant de nourriture par 100 g de poids que ceux utilisés pour le contrôle. Il ont par contre bu davantage. La durée du cycle ovarien a été allongé de 24% (p < 0,001) alors que le nombre de jours avec proestrus et estrus a été réduit de 14%, respectivement de 20% et ceux présentant des signes de metestrus et diestrus a augmenté de 25 et 24% (p < 0,001). Le taux d'assimilation du premier groupe a diminué de 47% (p < 0,01) par rapport au second. On n'a pas constaté de différence en ce qui concerne le nombre de corpora lutea. Par contre le nombre de morulae et de blastocystes de 4 jours a été de 25% (p < 0,01) inférieur chez les rats acclimatés à celui des rats de contrôle.
Similar content being viewed by others
References
BARRY, L.W. (1920): The effects of inanition in the pregnant albino rat, with a special reference to the change in the relative weights of various parts, systems and organs of the offspring. Contr. Embryol. Carneg. Inst., 11: 91–136.
BROBECK, J.R. (1960): Food and temperature. In: Recent Progress in Hormone Research. G. Pincus (ed.), Academic Press, New York, Vol. XVI; 439–459.
GUPTA, S.R. and LACY, B. (1967): Effects of protein calorie deficiency on the reproductive performance of female rats. Ind. J. Med. Res., 55: 904–910.
HAFEZ, E.S.E. (1968): Environmental effects on animal productivity. In: Adaptation of Domestic Animals. E.S.E. Hafez (ed.), Lea and Fabiger, Philadelphia, 74–93.
HERRINGTON, L.P. and NELBACH, J.H. (1942): Relation of gland weights to growth and aging processes in rats exposed to certain environmental conditions. Endocrinology, 30: 375–386.
HOWARD, B., MACFARLANE, W.V., OSTWALD, M. and PENNYCUIK, P.R. (1959): The effects of season and of life at 33°C on fluid distribution, reproduction and behaviour of albino rats. J. Physiol. (Lond.), 146: vi-vii.
KRAICER, P.F. (1967): Studies on the mechanism of nidation. XXIV. Isolation and study of intra uterine ova from the rat: technique and observations. Int. J. Fertil., 12: 320–328.
MACFARLANE, W.V., PENNYCUIK, P.R. and THRIFT, E. (1957): Resorption and loss of foetuses in rats living at 35°C. J. Physiol. (Lond.), 135: 451–459.
MACFARLANE, W.V., PENNYCUIK, P.R., YEATES, N.T.M. and THRIFT, E. (1959): Reproduction in hot environments. In: Recent Progress in the Endocrinology of Reproduction. C.W. Lloyd (ed.), Academic Press, New York, 81–96.
PENNYCUIK, P.R. (1964a): The effects on rats of chronic exposure to 34°C. III. Appetite. Aust. J. biol. Sci., 17: 236–244.
PENNYCUIK, P.R. (1964b): The effects on rats of chronic exposure to 34°C. IV. Reproduction. Aust. J. biol. Sci., 17: 245–260.
RAY, D.E., ROUBICEK, C.B. and HAMIDI, M. (1968): Organ and gland weights of rats chronically exposed to 22° and 35°C. Growth, 32: 1–12.
RINOLDINI, L.M. (1950): Effect of malnutrition as compared with hypophysectomy on organ weight of the albino rat. J. Anat., 84: 262–271.
ROBENS, J.F. (1968): Influence of maternal weight on pregnancy, number of corpora lutea, and implantation sites in the golden hamster (MESOCRICETUS AURATUS). Lab. Anim. Care, 18: 651–653.
SHAH, M.K. (1956): Reciprocal egg transplantation to study the embryouterine relationship in heat-induced failure of pregnancy in rabbits. Nature (Lond.), 177: 1134–1135.
SHORT, R.E., PETERS, J.B. and CASIDA, L.E. (1968): Effect of two levels of feeding on ovarian activity, embryo survival and ovarian compensatory hypertrophy in the rabbit. J. Anim.Sci., 27: 701–704.
SUNDSTROEM, E.S. (1930): Contribution to tropical biochemistry and physiology. II. Supplementary experiments on rats adapted to graded levels of reduced cooling power. Univ. Calif. Publ. Physiol., 7: 103–195.
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
Sod-Moriah, U.A., Pollack, E. Food and water consumption and the reproductive performance of the heat—acclimated female rat. Int J Biometeorol 14, 293–300 (1970). https://doi.org/10.1007/BF01742073
Received:
Issue Date:
DOI: https://doi.org/10.1007/BF01742073