M. W. Olsen

Embryonic Development in Turkey Eggs Laid 60-224 Days Following Removal of Males

Summary A delayed and retarded type of embryonic development occurred in 16.7% of the Beltsville Small White turkey eggs laid 54-224 days after the females were separated from males. This development in most instances could not be detected macroscopic-ally earlier than the 4th day of incubation. The embryonic membranes usually discontinued their growth after covering an area of the yolk equal to that occupied by a normal 2- to 3-day turkey embryo. In most instances no embryo could be detected macroscopically although serial cross sections showed a definite organization on the part of centrally located cells. Two living embryos were found in eggs laid 78 and 98 days respectively after the hens were separated from the males. These embryos, after 8 days of incubation had attained a size equivalent to a normal 4-day turkey embryo. The embryonic hearts were still beating and there was a well developed vascular system in both cases. A 7-day embryo, with a well-developed vascular system was also found in an egg which had been incubated 11 days. This egg was laid 195 days after the female had been separated from males.

Nine year summary of parthenogenesis in turkeys.

Summary A breeding program for increasing parthenogenetic development, based on the progeny test method, was initiated in 1954. More than 42,000 eggs from 926 Belts-ville Small White virgin turkey hens were involved in this 9-year study. A marked increase in incidence of parthenogenesis, particularly of the more highly organized type, has resulted. Parthenogenetic development was observed in 16.7% of the eggs tested in 1952, in 41.7% in 1959. In 1952, embryos were encountered in 0.2% of all eggs whereas in 1959 11.7% of the eggs were so classified. Of 44 embryos found in 1954, 4 or 9% survived until 21-28 days of incubation; in 1960, 87 of 277 or 31.4% did so. Since 1956 a total of 67 embryos, all males, have survived to hatching, a few reaching maturity. Three males produced spermatozoa and one sired offspring.

Time Required for Induction of Ovulation Following Intravenous Injection of Hormone Preparations in Fowl

Summary The time at which ovulation occurs following intravenous injection of appropriate hormone preparations into pretreated and normally laying (non-pretreated) hens has been determined. The interval in pretreated hens averaging more than 2 ovulations per hen at time of autopsy was 6.8 hours, range 6.1-7.2 hours. Ninety percent of all normally laying hens (69) ovulated from 6.5 to 8.5 hours following ovulatory injection, the remaining 10% of injected hens requiring up to 9.6 hours for ovulation. The non-pretreated hens were injected with 4 different hormone preparations administered at differing dosage levels and at times calculated to effect ovulation of follicles at varying degrees of prematurity. The minimal ovulatory interval recorded for pretreated hens was 6.1 hours, for non-pretreated hens, 6.5 hours.

Role of vitamin B12 in reproduction of poultry.

Summary When hatching eggs laid by Rhode Island Red hens fed a diet deficient in vitamin B12 were injected with crystalline vitamin B12, the hatchability was improved. Among the chicks hatched from vitamin B12 injected eggs, the growth rate was greater, the mortality lower and the feathering better than among chicks hatched from H2O-injected and non-injected eggs.

Frequency and Cytological Aspects of Diploid Parthenogenesis in Turkey Eggs

SummaryNaturally occurring parthenogenesis in unfertilized turkey eggs was encountered at this station in 1952. Since its discovery, selective breeding on a family basis has been practiced yearly in an attempt to further intensify this trait in certain lines of turkeys and chickens.Cytological studies likewise have been conducted and various experimental procedures employed in an attempt to develop a clearer picture of just where and the manner by which diploidy is restored. Available Cytological data and indirect evidence secured in related studies indicate that restoration of diploidy in unfertilized turkey ova is due to suppression of the second polar body. It would appear that in the absence of sperm, meiosis II is not completed. Chromosomes of the second polar body and those of the egg pronucleus probably never completely separate and subsequently the unfertilized ovum resumes development with a diploid complement of chromosomes.Four potential uses of unfertilized turkey eggs and parthenogenetic poults in biological research are given.

Treatment of Cecal and Liver Trichomoniasis in Turkeys by Fever Therapy

Since 1937, experimental work has been in progress on the use of fever therapy for the cure of cecal and liver trichomoniasis in turkeys, a widespread disease of domestic fowls caused by the protozoan parasite, Trichomonas gallinarum. This organism invades the tissues of the lower digestive tract of birds and in chronic infection produces lesions in the ceca and liver. These lesions closely resemble, and undoubtedly have been often confused with, those produced by Histomonas meleagridis in the disease commonly known as blackhead. Birds with chronic trichomoniasis are droopy in appearance, refuse to eat, and lose weight. The droppings become quite liquid and light yellow in color. Young birds usually die 4 to 8 days after exhibiting the first symptoms of the disease, although in mature birds the period between the first symptoms and death may be much longer. Most of the turkeys used in this preliminary study were naturally infected and ranged from 3 to 18 months in age. At the beginning of the work the disease was diagnosed by the external symptoms noted above, and by microscopic examination of the cecal discharges. Recently it has been found that by making an incision into the abdominal cavity, and with the aid of a strong light, it is possible to observe the liver and ceca directly for lesions. The direct observation of lesions and identification of trichomonads in cecal droppings have made certain the elimination from treatment of birds exhibiting external symptoms similar to those of trichomoniasis but actually due to other causes. Birds undergoing treatment were placed in a thermostatically controlled cabinet for periods ranging from 1 to 2 hours. The internal body temperature of the bird was raised from 2 to 6 degrees above the normal of 106.5°F by maintaining an air temperature within the cabinet of approximately 104°F, and a relative humidity of 60 to 70%.

Parthenogenesis in Eggs of White Leghorn Chickens Following an Outbreak of Visceral Lymphomatosis.

Summary Four Single Comb White Leghorn hens of a nonparthenogenetic strain, following a severe outbreak of visceral lympho-matosis, produced a significant number of unfertilized eggs, which upon being incubated, underwent parthenogenetic development. One hen (9243) produced unfertilized eggs, 37.5% of which exhibited parthenogenesis. This hen was subsequently mated to a Dark Cornish male from a strain averaging 5-7% parthenogenesis. Each of 8 virgin daughters of hen 9243 produced some eggs which underwent parthenogenetic development. Eggs of individual hens varied from 13 to 57%, while the average for the entire group was 32.7. Daughters of hen 9243 were subsequently mated first to Dark Cornish males and later to White Leghorn males of Beltsville breeding (non-parthenogenetic strain). Tests for parthenogenesis involving eggs of progeny revealed that the predisposition to parthenogenesis was transmitted from parents to progeny. Use of White Leghorn sires, however, tended to suppress parthenogenesis in eggs of their virgin daughters, while Dark Cornish males allowed a fuller expression of this trait.

Effects of Prior Semen Injections and Weekly Inseminations on Hybridization of Chickens and Turkeys

Summary Eight weekly artificial inseminations of Beltsville Small White turkey hens with Dark Cornish chicken semen were only partially successful in achieving cross-fertilization. Identifiable hybrid embryos were produced only in an 18-day period immediately following the first insemination. Intraperi-toneal injections of turkey hens with chicken semen in Freunds adjuvant before artificial insemination by the same semen donors suppressed the ability of their subsequent eggs to undergo hybrid embryonic development. Similar injections of adjuvant alone had no suppressing effect.

Chemically Induced Degeneration of Chick Mesonephros.

Summary In an experiment on the toxicity of various chemicals on developing chick embryos it was demonstrated that the kidneys of 10- and 15-day embryos were severely damaged by injections of various chemicals. The kidneys of older embryos, those of day-old chicks, and those of control embryos of various ages treated with distilled water gave no evidence of kidney degeneration. From the experiment it appears that the chemical substances injected had a toxic effect on the mesonephros but not on the metanephros.

Function of egg white in embryonic development.

In an attempt to decide whether or not the yolk or the egg white is the carrier of a growth factor transmitted through the egg from the hens feed to the chick, the experimental technic described here was devised. In the past it has been assumed that egg white has a purely nutritional function in the growth and development of the chick embryo, but no experimental evidence exists to support this supposition. The yolk also furnishes food, but in addition the yolk-sac serves as an organ for the digestion and assimilation of food by the chick embryo. This function of the yolk-sac indicates a structural relationship between the embryo and the yolk. In this experiment fertile hens eggs from crosses of Rhode Island Reds and White Leghorns were used. A circular window approximately 1/4 inch in diameter was bored in the small end of each egg and the egg-white was removed into a glass ground-joint wash bottle by suction. To combat bacterial infection 0.1 cc of an aqueous solution containing 3000 I.U. of penicillin and 3.3 mg of streptomycin was injected into each of the eggs so treated. The egg white from another fertile egg was then transferred by air pressure from the wash bottle into the egg from which the egg white had previously been removed. When one egg white was not sufficient to completely refill the shell, that from another fertile egg was added. Thus, at times egg white from more than 1 egg was used for replacement in a single egg. After the egg was completely filled with egg white, the window in the shell was closed with a strip of scotch tape and the egg placed into an incubator for 3 weeks. At intervals of 7 days, the condition and development of the chick embryo was observed by candling the eggs. In the first successful series, 12 such eggs were prepared; of these 3 chicks hatched which were normal in every respect. Of the rest of the embryos, two lived 2 days, one 4, two 6, one 7, one 13, one 15 and one 21 days. These are probably the first live chicks produced after such drastic treatment. This experiment demonstrates that the chief function of the white of the hen egg is mainly to furnish food for the developing embryo. It has been previously held that the two chalazae serve to orient the embryo in a proper position for hatching by keeping the yolk more or less fixed. In these experiments, however, the two chalazae were removed with the egg white and thus the position of the developing embryo depended upon gravity. Further work is in progress on the nutrition of the chick embryo employing this technic.