How are double-yolk eggs formed? Can they hatch twin chicks? | Ficus microcarpa

Hello, I am Brother Rong from the China Science and Technology Museum. Welcome to Brother Rong's Science. I guess you have all seen double-yolk eggs, but they seem to taste no different from ordinary eggs. But double-yolk salted duck eggs are different, they are so rich in flavor. After all, the yolk is the concentrated area of ​​​​nutrition in chicken and duck eggs, and the nutritional value of double yolks is indeed higher than that of single yolks. However, in production, double-yolk eggs belong to the category of abnormal eggs. Are you a little nervous? Abnormal eggs? Is it caused by hormones? Can it still be considered a healthy food? Or can a double-yolk egg hatch two chicks? The answer has to be found from the origin of double-yolk eggs.

The structure of a normal egg from inside to outside is the yolk. The yolk is wrapped in a layer of yolk membrane. The small white dots on its surface that can be barely seen by the naked eye are called ovules when unfertilized. After fertilization and a certain period of development, this small dot will grow into an embryonic disc. The thin albumen and the thick albumen are wrapped around the outside of the yolk in turn. The egg white is outside the eggshell membrane, which is divided into two layers, the inner and outer layers. The gap formed at the blunt end of the egg, which is the big end, is called the air chamber. The outermost layer of the egg is the hard eggshell that plays a protective role. Any egg that does not conform to these normal structures is called an abnormal egg.

How is a normal egg formed? First, a mature yolk separates from the hen's ovary, is received by the funnel of the oviduct and stays there for a short time, and fertilization is also completed here. After that, the yolk enters the oviduct dilatation, and is coated with thick and thin egg whites in turn. After the coating is completed, it moves down into the isthmus to form the inner and outer eggshell membranes, and finally the eggshell, pigment and gelatin film are deposited in the uterus, and a complete egg is formed. Those with two yolks, no yolks, soft shells, sandy shells, etc. are all abnormal eggs. The appearance of double yolk eggs is simply an assembly error. It is not a science and technology or hard work, but a normal error range.

Then, let's ask further, why is there an assembly error? The direct reason for the formation of double yolk eggs is that two yolks are discharged into the oviduct at the same time. It may be that during the first or peak production period, the hen has just started to lay eggs, and various functions are still unstable. Due to the disorder of hormone secretion, two yolks are discharged at the same time, and the egg white and eggshell are wrapped in the oviduct to form a double yolk egg. It may also be that one yolk is mature and discharged, and the other immature yolk is discharged at the same time as the mature yolk due to the rupture of the follicle gap caused by the hen's frightened leap, forming a double yolk egg. The formation of double yolk eggs is affected by many factors: first of all, genetic factors. Different breeds of laying hens have different probabilities of producing double yolk eggs. Studies have found that the follicles in the high-yield group are well developed, with abundant and tightly arranged granulosa cells; the follicles in the low-yield group are slow to develop, with a large number of atresias, and the granulosa cells are loose and have a single-layer structure. That is, the follicles develop quickly, and the number of follicles that mature at similar times is large, which increases the possibility of simultaneous discharge. The second is nutritional factors. Hens fed with feed with low energy and high crude protein are more likely to lay double yolk eggs. In addition, estrogen, follicle stimulating hormone, and gonadotropin-releasing hormone can all promote the production of double yolk eggs. Finally, in terms of feeding and management, stress, premature light supplementation, etc. may all lead to the production of double yolk eggs.

As for whether the double-yolked eggs can successfully hatch chicks? This is almost impossible in production. The space inside the eggshell is limited, and the nutrients and oxygen in the double-yolked eggs cannot meet the development needs of two chicks, so double-yolked eggs are only sold and not used for hatching. This is completely different from human twins. Of course, there is no hidden danger in eating double-yolked eggs, it's just that the yolk is eaten too much.

Because double yolk eggs are abnormal eggs, they are considered defective products for farms. In order to ensure stable and controllable quality, merchants have put a lot of effort into providing nutritionally balanced feed, creating a comfortable and quiet breeding environment, and strictly following the immunization procedures. After all, egg laying in laying hens is now more like an assembly line operation in a factory. Making fewer mistakes and no mistakes is what merchants pursue. You can rest assured!