Factors affecting egg size and their regulation (above)

In China, consumers in different regions have different eating habits and have different preferences for the color and size of eggs. In contrast, the north prefers large eggs with red shells, while the south prefers small pink eggs. Nowadays, laying hen farmers can meet people's consumption needs by regulating the size and weight of eggs. ChickenThe size of an egg is generally expressed in terms of both weight and shape. Overall, each egg weighs about40~70Between grams, ordinary red-shelled eggs, which are circulated by the market.Mostly50~60g. Under different physiological conditions, chickens occasionally produce5~30The skinny little eggs of the gram,Generally, there is no egg yolk. Occasionally, giant eggs of more than 80 grams can be produced. There are two egg yolks, which are commonly known as "double yolk eggs" (caused by strong production capacity). We usually use the egg shape index to express the shape of the egg, which is the ratio of the length of the egg's longitudinal diameter to the length of the egg's transverse diameter. Under normal conditions, the egg shape index is usually between 1.3 and 1.35, higher than the 1.35 belongs to the slender, lower than the 1.3 belongs to the nearly spherical. So what are the factors affecting egg shape and egg weight? How to control?

Genetic breeding, feed nutrition, environment and disease, feeding and management all have different effects on egg weight and egg shape.

1 genetic factors

The egg shape of eggs is mainly affected by genetic genes. Breeding companies use genetic improvement to control the individual size of chickens.Small and the size of the egg, China Agricultural University's grain-saving laying hens are a species that produces smaller eggs; and larger varieties, such as Isa Brown and Romain Brown, produceThe eggs are bigger.

2 feed nutrition factor

Feed nutrition mainly affects egg weight. Egg weight is largely affected by the intake of crude protein, specific amino acids (methionine, cystine), energy, fat and essential fatty acids (plus linoleic acid) and vitamins. The effect of methionine on egg weight is more intuitive, reducing the content of methionine in the diet not only reduces the egg weight, but also causes the egg production rate to decline. High energy and low protein level diets can keep the egg weight at a moderate level, while keeping the number of eggs laid at a high level and prolonging the peak laying time. In addition, change the vitamins in the feed, such as vitamin AThe content of vitamin E can also cause changes in egg weight. Adding linoleic acid can promote the increase of egg weight, when linoleic acidThe proportion increased2.83％When, the egg weight can reach59.6g.

2.1energy level. Studies have shown that energy intake is the most critical factor affecting egg production, while amino acids and protein intake is the most important factor in determining egg weight.The key factor. Known under ideal conditions (Sherwin18~25C), the daily generation of light and medium laying hens during the laying period.Xie can need respectively280~300,320~350 kca1. The effect of dietary energy level on egg weight is mainly through feed intake. If the daily energy intake of laying hens is lower than the lower limit of the above value, egg production and egg weight will be affected and reduced, thus affecting the protein intake. The premise for hens to make efficient use of amino acids and proteins to maintain, lay eggs and increase egg weight is that laying hens have a high energy intake, that is, chickens must first have a feed intake to meet energy needs.

2.2Coarseprotein level. Protein intake is the main nutritional factor affecting egg weight. For Hailan Brown commercial laying hens, the daily protein intake is generally not less than 17.5.g. There are testsShow that when feeding contains.More than 17% crude protein (about 26 ~ 27% cp43 soybean meal) feed hens, the protein intake and egg weight is proportional. But the eggs are too big for their eggsThe shell is of poor quality, prone to breakage, and the production of larger eggs can cause damage to the hen's reproductive tract, increasing the risk of disease infection, paralysis andprolapse of the anus and other issues.

Adjustment of dietary protein levels can change the size of eggs, dietary crude protein levels of each increase or decrease1％，As from16% increase or decrease to 17%or15％，About can make the egg weight increase or decrease1g. In actual adjustment, it is better not to increase or decrease protein by more than one hundred each time.Points.

2.3amino acid levels. Amino acid nutrition is the essence of protein nutrition. When the early weight of laying hens is lower than the standard, an appropriate increase in the amount of methionine added to help increase the egg weight. This may be due to the added methionine compensating for the need for continued growth. However, each chicken of Isa brown commercial layer needs not only 460mg per dayFor the above methionine, 840mg lysine should be ingested to reach the standard egg weight.

2.4Fats and essential fatty acids. Involvement of linoleic acid in essential fatty acids in lipidLipid metabolism can affect egg size through its effect on the yolk. The current level of linoleic acid in the diet to ensure maximum egg weight.think1.5%. Because corn, soybean meal and soybean oil all contain a large amount of linoleic acid, the corn soybean meal diet does not need to add linoleic acid, and the miscellaneous meal diet can increase the egg weight by adding appropriate amount of fat.

2.5Mycotoxin contamination and drug effects. Many studies have pointed out that certain drugs (such as pesticides, chemical emissions, etc.) and feed pollution can seriously affect egg size. Just like the chicken to eatTo grains contaminated with dibromoethylene can cause a significant reduction in egg size. Feed per kilogram10~12.3mg furazolidone feed, continuous 10Over the day, it can quickly cause the egg to become smaller, and small egg problems can last for a long time after stopping feeding. In the feed contaminated by mycotoxins, aflatoxins and trichothecene toxins often cause intestinal mucosal ulcers and oviduct inflammation in chickens, resulting in abnormal egg shape, light color and decreased egg weight.