Biology of Embryo Development in Pigeon Columba livia domesticus in Conditions of Artificial Incubation

Monika Łukasiewicz^1*, Karolina Wnęk², Karolina Boruc¹

*Corresponding author:monika_lukasiewicz@sggw.pl

ARTICLE CITATION: Łukasiewicz M, Wnęk K, Boruc K (2014). Biology of embryo development in pigeon Columba livia domesticus in conditions of artificial incubation. Adv. Anim. Vet. Sci. 2 (7): 401 – 406.
Received: 2014–06–24, Revised: 2014–08–14, Accepted: 2014–08–15
The electronic version of this article is the complete one and can be found online at ( http://dx.doi.org/10.14737/journal.aavs/2014/2.7.401.406 ) which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited

ABSTRACT

The study was conducted on the eggs of pigeon Columba livia domesticus collected in an amateur pigeon breeding facility during the breeding season. Eggs were collected in the morning from the long–beaked pigeons to make sure that they have been laid recently. They were incubated at 37.8^oC and humidity of 65% (standard conditions for the development of the domestic chicken embryos). A total of nearly 70 embryos have been analyzed at different stages of development. 4 fertilized eggs were opened every day and analyzed for external morphological features according to the Hamburger and Hamilton key (1951). It was found that the embryonic development of pigeon Columba livia domesticus was shorter (17 days) by about 4 days compared with embryos of domestic chicken Gallus gallus domesticus (21 days). Further, it was observed that the pigeon embryos developed slower in the first 14 days of embryogenesis, and a marked acceleration of their development occurred from day 14 of incubation. Artificial incubation enables successful raising of Columba livia domesticus pigeon chicks. The remaining period of the growth and development of chicks is possible by placing them with foster parents, long–beaked pigeons.

INTRODUCTION

The rock dove (Columba livia), living in southern Europe, southern and central Asia, and northern Africa is considered an ancestor of domestic pigeons. The gray–blue coloring of this pigeon is similar to that of homing pigeon (Milan and Slavibor, 1995). The wild rock dove is medium in size and resembles the so–called feral urban pigeon, present almost all over the globe. Domestic pigeon is a species, which domestication was a success at the turn of the century. Pigeon breeding belongs to the ancient human activities, and over time it acquired a completely different character, i.e. ornamental and sporting use of these birds. At the beginning they were kept on religious grounds, and only later used for postal purposes (Nowicki et al., 1996). The harvest and storage of cereal crops caused the wild animals to search for the human households where they could easily find food. People also benefited from the presence of these birds, e.g., in the form of eggs. Man was accompanied by a pigeon throughout the development of civilization. When people began to build the cities with tall buildings and towers that resembled natural nesting places of these species such as rocks, the birds began to settle there and the population increased (Tomiałojć and Stawarczyk, 2003). In some cultures, pigeons were considered sacred, because it was claimed that God itself sent them down on church towers. Pigeon has played a very important role in Christian symbolism. The symbol of this bird is often encountered in the catacombs. It is in the form of a dove that people imagined the soul after death reaching into heaven, similarly as the figure of the Holy Spirit descending upon the earth (Herman, 1963). Taylor (2006) wrote that in the Old Testament, pigeons were one of the main birds of sacrifice, but in the New Testament they were primarily associated with the baptism of Christ. Pigeons are also a symbol of hope, new life, peace and abundance, spiritual and material goods, and the forgiveness that God sent down to the Noah's Ark under the symbol of a bird (Cooper, 1998). The Islamic religion considers this bird to be holy, because it protected Muhammad during his escape (Herder, 1992). Litwiński (1995) reported that some of the earliest information on the breeding of these birds came from the third and fourth centuries BC from the land of Egypt. Reliefs have been discovered in the tombs of the pharaohs, which depicted scenes with pigeons, e.g., the release of homing pigeons or doves receiving nourishment. Cypriot excavations of dovecotes created on the model of small chapels are dated to the same time period (Herman, 1963). This species and its breeding spread to areas of current Italy, Spain and Greece with the expansion of the Phoenicians in the Mediterranean, where to this day paintings can be find with the image of a dove. Peterfi (1977) reports that thanks to the Greeks domestic pigeon spread across the area of Italy of that times, where it was called "colymbos", hence the Latin name columba of this bird. In the first century BC the Roman scholar Varro has described for the first time the then breeding of pigeons, in his famous work "Rerum rusticarum". He listed the rock dove, common wood pigeon, and described the dovecotes, rearing of young birds, feeding and their local market price. Pigeons have been used to convey messages due to the incredible "sense of navigation" and the speed and fluidity of the flight. Dovecotes were also installed on fishing boats, where the birds were sent with information about the shoals of fish. Numerous military expeditions and commercial communication widened the worship and range of pigeon breeding facilities, also in Asia, where the famous scholar Avicenna, in his work "Canon Medicinae'' of the eleventh century, mentioned the dietary value of meat of these birds. This species came to Europe via Arab nations.

The aim of the study was to analyze the biology (preparation of the key) of embryo development of pigeons Columba livia domesticus in conditions of artificial incubation.

MATERIALS AND METHODS

Description of Experimental Material
Eggs were collected in an amateur pigeon breeding facility during the breeding season. There were two groups of birds, i.e., long–beaked and short–beaked pigeons (without the possibility of feeding their offspring). For this study, eggs were collected in the morning from long–beaked pigeons, serving as foster parents for short–beaked pigeons to make sure that they have been recently laid, planting them at the same time the eggs of short–beaked pigeons.

Incubation
The eggs were incubated at 37.8^oC and humidity of 65% (standard conditions for the development of the domestic chicken embryos) in a hatching incubator (Heka, Germany) equipped with a module controlling the temperature, humidity and egg–turning system. The apparatus had insulated glazing, interior lighting, automatic egg turning, 3 breeding drawers for selected species of birds, 2 hatching drawers and 5 liter canister of water capable of maintaining the preset humidity.

Prior to placing the eggs into the incubator, they were weighed individually on a technical scale to the nearest 0.01 g and then x–rayed and re–weighed weekly to determine the weight loss of eggs.

Embryo Analysis
A total of nearly 70 embryos have been analyzed at different stages of development. 4 fertilized eggs were opened every day and analyzed for external morphological features according to the Hamburger and Hamilton key (1951). The eggs were taken out of the incubator after 12 h, (a single batch of eggs had 4–6 pieces) and left at about 17–18^oC in order to cool the surface of the shells. This was aimed at slowing down the development of embryos, which were positioned just underneath the eggshell membranes and preventing possible differences in their morphological assessment.

Eggs were opened using the method described by Callebaut (1981), involving the creation of an artificial air chamber over the embryo. Blastoderm was stained by the introduction of India ink (KOH–I–NOOR Hardtmuth) into the space under the embryo. The surface of the blastodisc was then fixed with 1% acetic acid, and the preparation was observed under binocular at 25x magnification.

Photographic documentation was made with the use of microscope Nikon Model Eclipse E 200 MV RS Tokyo, Japan with built–in camera. Images were taken at 60x magnification and in some cases at 10x and 200x. Additionally, a digital camera Canon EOS 50D was used. Image processing was performed using Microsoft Photo Editor.

The material analyzed has become part of the didactic material of embryology at the Department of Poultry Breeding.

RESULTS AND DISCUSSION

Biological Analysis of the Clutch
All bird species are egg–laying animals. The size and shape of the egg as well as the color of the shell and the number of eggs in the clutch is specific and often quite different for various species of birds (Christians, 2002). As it might be expected, the size of the egg is approximately related to the size of the bird. The size of the clutch is influenced by factors such as natural selection, or the ability to feed a certain number of young, which particular species can successfully raise without fear of malnutrition due to the necessity of division of existing food supplies among a large number of hungry chicks. The successive phases of the reproductive cycle in pigeons comes so rapidly that often a female laying eggs to the next nest can be observed, while the male is still feeding young from the first clutch. The variability of the number of hatches in different species and the associated number of young raised in one breeding season, are a reflection of fundamental differences in growth and survival chances of the young birds.

Average weight of eggs of pigeons in the experiment was 15.71 g. of the farm birds only quail eggs have a lower weight (11.3 g) (Kul and Seker, 2004; Ayasan et al., 2006; Adamski, 2008). The tiny hummingbird lays the smallest eggs, weighing less than 1 g, while the ostrich lays the largest. The size of an egg is also to some extent dependent on the amount of nutrients stored therein, and the type and degree of care that developing chicks receive from their parents.

The egg weight control was carried out in this study in order to determine their weight loss. During the incubation, the eggs were losing their initial weight, mainly due to the loss of water. The average egg weight difference between the beginning and the end of the incubation was 3.02 g. Egg weight loss was very diverse, which resulted from large differences in the initial weight of the eggs tested (Table 1). It was found that the average weight loss of incubated eggs of pigeons for the whole incubation period was 18.14%, which is much higher compared to the domestic chicken eggs. According to Borzemska (1996), during normal hatches, hen's egg is losing about 12% of its mass after 18 days of incubation.