BIOLOGY OF REPRODUCTION 8, 283-298 (1973) Development, Cellular Growth, and Functon of the Avian Ovduct Studies on the Magnum During a Reproductive Cycle of the Domestic Fowl (Gallus Domesticus) Downloaded from https://academic.oup.com/biolreprod/article/8/3/283/2768726 by guest on 23 September 2021 JOHN Y.-L. YU ANI) R. R. MARQUARDT Department of Animal Science, University of Manitoba, Winnipeg, Manitoba Canada Received December 29, 1971; accepted October 24, 1972 The biochemical composition and histological patterns of the magnum portion of the domestic fowl (Gallus domesticus) oviduct during the developing, laying, and molting (regressing) stages of a reproductive cycle were compared. Growth and development of the magnum are primarily associated with hyperplasia (increase in total DNA) and to a lesser extent with cellular hypertrophy (increase in ratios of dry matter/DNA). A continuous hyperplasia occurs in the magnum during the laying stage; changes in cellular hypertrophy, however, are not observed. The pattern during regression of the magnum in the molting stage is essentially a reversal of that of the developing oviduct. Histological observations identify the characteristic changes as being differentiation and formation, secretion, and involution of tubular gland cells, respectively, for the developing, laying, and regressing oviducts. The ratios of RNA/DNA, protein/DNA, and soluble protein/DNA increase, reach maxi- mum, and decrease during the developing, laying, and molting stages, respectively. The ratios of insoluble protein/DNA and lipids/DNA remain relatively constant throughout the whole reproductive cycle. The secretory egg white proteins (oval- bumin and conalbumin) increase very rapidly during the developing stage and decrease in a similar manner during molt. Conalbumin is present in the magnum and in the blood of the female chicken at all stages of the reproductive cycle. Ovalbumin, in contrast, is not located in the very small oviduct. It appears shortly after tubular gland formation. There is a quantitative shift of A2- to Al-ovalbumin during the developing stage which is reversed during regression of the oviduct. INTRODUCTION bandov, 1956; Sturkie, 1965). The oviduct It is well known that the tremendous attains its maximum size during the laying change in the size of the avian oviduct stage which lasts approximately 12 months. during various reproductive stages is asso- Thereafter, the hen goes into a resting pe- ciated with its physiological performance riod (molt) for about 2 months during and that this process is regulated by sex which there is regression of the oviduct hormones (Dorfman and Dorfman 1948; (Romanoff and Romanoff, 1949; Sturkie, Brant and Nalbandov, 1956; Sturkie, 1965; 1965). The developing, laying, and molting O’Malley et at, 1969; Oka and Schimke, sages thus constitute a reproductive cycle 1969a,b; Yu et at., 1971). In the domestic of the egg-producing fowl. egg-producing fowl (Galtus domesticus), The histology of the domestice fowl ovi- rapid oviduct development occurs about duct has been investigated (Richardson, 2 months prior to the onset of laying 1935; Brant and Nalbandov, 1956). (Hafex and Kamar, 1955; Brant and Nal- Studies on compositional changes of fowl 283 Copyright © 1973 by The Society for the Study of Reproduction All rights of reproduction in any form reserved. 284 YU AND MARQUARDT oviduct at certain stage(s) in a reproduc- weighed, and placed in a polyethylene bag which tive cycle have recently received atten- was immediately dropped into an ethanol-dry ice tion (Oades and Brown, 1965; Chechotkin, medium. Frozen magna were pooled into duplicate samples on an oviduct weight basis within the 1966; Belnave and Squance, 1968; Cecil reproductive stage, reweighed, and lyophilized. and Bitman, 1970; Yu et at., 1971). There The dried samples were ground and stored in have been, however, no studies on the se- a dessicator at -15#{176}C until required. Egg white quential changes in overall patterns of cel- from freshly laid eggs was lyophilized and stored lular growth and development of the avian at -15#{176}C. Downloaded from https://academic.oup.com/biolreprod/article/8/3/283/2768726 by guest on 23 September 2021 oviduct during a reproductive cycle. This Chemicals. Calf thymus DNA (type V), yeast RNA (grade VI), orcinol monohydrate, ovomucoid investigation was, therefore, carried out in (type II-o), conalbumin (type III), and globulins an attempt to illustrate systematically the (egg white) were obtained from Sigma. Oval- biochemical and morphological patterns of humin (two times crystallized) was from the magnum (albumen1secreting region) Worthington Biochemical Corporation. Acryl- of the domestic fowl oviduct during a re- amide, N, N’-methylene bisacrylamide and N, N, N’, N’-tetramethyl ethylenedianiine (TEMED) productive cycle. Biochemical determina- were obtained from Canal Industrial Corporation. tions include the alterations in the levels Complete Freund’s adjuvant and Noble agar were of major cellular components: DNA, RNA, purchased from Difco Laboratories. Diphenyl- lipids, and various protein and nitrogen amine was from Matheson, Coleman & Bell. fractions including secretory egg white Chemical analysis. A single analysis on each protein patterns. Histological observations of the duplicate pooled samples of magna was carried out. Nucleic acids were extracted by the include the formation, secretion, and in- method of Schneider (1945) with perchloric acid. volution of tubular gland cells as well as DNA was measured by the modified diphenyl- the changes in cell size. The nature of amine reaction (Ciles and Myers, 1965) with calf growth and development of the domestic thymus DNA as standard. RNA was assayed by fowl oviduct, in association with its func- the modified orcinol method (Ceriotti, 1955) with tion, during a reproductive cycle is il- yeast RNA as standard. Lipids were extracted with a chloroform-methanol mixture and were esti- lustrated at the cellular level. mated by weighing (Folch et al., 1957). MATERIALS AND METHODS Fractionation of protein and nitrogen compo- nents. The nitrogenous components in oviduct tis- Source and treatment of birds. Single Comb sue have been classified into protein and non- White Leghorn commercial hybrids (Dekalb protein nitrogen with each subfraction being com- strain) were obtained from the University poultry posed of a soluble and insoluble portion (Dicker- flock and a commercial hatchery. The developing son and Widdowson, 1960; Munro and Fleck, oviducts were obtained from 3- to 5-month-old 1969). The nitrogen (N) content of the above chickens. Oviducts from 5-, 8-, and 14-month-old fractions was determined in this study by the (first-laying cycle) and from 22-month-old (sec- following procedure. An aliquot of the lyophiuized ond-laying cycle) hens were selected for the laying tissue was homogenized at 0#{176}Cin a Willem Poly- stage. Oviduct regression (molting) in laying hens tron (Brinkmann) in 40 volumes of 100 mM KC1, was induced by controlling the feeding and water- 50 mM sodium phosphate buffer (pH 7.0) and ing schedule (Smith et al., 1957). The molting centrifuged at 50,000 x g for 30 min. The protein hens were sacrificed at weekly intervals during in the supernatant fraction (soluble N) was pre- the 3-month experimental period. A summary of cipitated with 3 volumes of 10% trichloroacetic the number of birds and the oviduct weights for acid (TCA) and was centrifuged at 50,000 x g the various reproductive stages is presented in for 20 mm. The total N (extract), soluble N Table 1. (50,000 x g supernatant), insoluble N (50,000 x Sample preparation and storage. After decapita- g precipitate) and soluble nonprotein N (50,000 tion of the bird, the oviduct was removed and x g TCA supernatant) were determined by the weighed. The magnum region was then sectioned, micro-Kjeldahl method (Horwitz, 1965). Insolu- 2 The nomenclature of egg white proteins in ble nonprotein N (nucleic acid N) was calculated the present study is according to Romanoff and from the nucleic acid content which was deter- Romanoff (1949) and Warner (1954). Egg albu- mined as described previously. The soluble and men refers collectively to egg white proteins (oval- insoluble protein nitrogen was obtained by dif- bumin, conalbumin, ovomucoid, etc). ference as shown below; soluble protein N AViAN 0VIDUCr GROWTh AND DEVELOPMENT 285 TABLE 1 CHANGES IN THE WEIGHT OF THE OvIDUcT AND THE MAGNUM IN CHICKENS DURING A REPRODUCTIVE CYCLE Average Average l)ry matter Average wet wet content body Num- weight of weight of of weight Reproductive her of Age oviductb magnumb Inagnumb of hird&’ stage#{176} birds (month) (g) (g) (%) (g) Downloaded from https://academic.oup.com/biolreprod/article/8/3/283/2768726 by guest on 23 September 2021 I)eveloping (I)) Dl 12 4-5 2.8 ± 0.6 0.5 ± 0.1 11.3 ± 0.4 1192 ± 78 D2 10 4-5 5.1 ± 0.9 1.0 ± 0.2 12.0 ± 0.2 1178 ± 97 D3 13 4-5 10.2 ± 1.6 2.5 ± 0.4 17.4 ± 0.8 1261 ± 116 1)4 6 4-S 19.2 ± 1.6 7.0 ± 1.1 23.3 ± 1.9 1376 ± 153 D5 5 4-5 26.4 ± 1.6 11.2 ± 0.9 24.3 ± 1.8 1446 ± 149 Laying (L) Li 6 5 37.2 ± 6.1 16.6 ± 2.8 26.1 ± 0.7 1496 ± 115 L2 6 8 41.0 ± 3.1 18.6 ± 1.7 24.7 ± 0.0 1708 ± 138 L3 6 14 50.8 ± 7.7 24.3 ± 3.4 24.9 ± 2.5 2081 ± 180 L4 6 22 51.0 ± 8.0 24.6 ± 5.9 24.5 ± 0.4 2114 ± 234 Molting (M) Ml 4 14-16 38.2 ± 4.2 18.0 ± 3.3 24.8 ± 1.1 1734 ± 189 M2 4 14-16 29.2 ± 2.2 11.6 ± 1.3 24.2 ± 0.6 1575 ± 145 M3 5 14-16 20.0 ± 2.3 7.3 ± 0.9 21.3 ± 1.8 1486 ± 135 M4 10 14-16 10.0 ± 1.7 2.7 ± 0.5 18.3 ± 0.1 1556 ± 167 M5 11 14-16 4.8 ± 0.9 1.2 ± 0.2 17.1 ± 1.4 1157 ± 137 M6 12 14-16 2.6 ± 0.5 0.6 ± 0.1 19.2 ± 0.4 1078 ± 113 “ The designations of D’s and M’s refer to oviducts of different weight within the developing and molting stages, respectively; while the L’s refer to oviduets from laying hens of varying age.