JPH0466532B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Field of Application] The present invention relates to a method for raising hens for producing pale-yolk eggs that yield pale-colored egg yolks with a lotus color fan number of 1 or less. [Prior Art] Generally, commercially available chicken eggs have yellow to orange yolks. The degree of egg yolk color ranging from yellow to orange is generally evaluated and ranked using the Rotsuyu color fan produced by Rotsuyu Co., Ltd. as a criterion value. Rotsuyu Color Fan is divided into ranks from 1 to 15, with lower numbers indicating a lighter egg yolk and higher numbers indicating a deeper yellow to orange color. Most commercially available chicken eggs have a yellow color with a rotisserie color fan number of 9 to 11. In addition, in recent years, egg yolks with less yellowness and closer to white color (hereinafter referred to as light-colored egg yolks) have been used in confectionery and other applications.
Chicken eggs (hereinafter referred to as light yolk eggs) are increasingly being requested. By the way, the yellow color of egg yolk is caused by the transfer of xanthophylls contained in the feed into the egg yolk, and commercially available chicken eggs have egg yolks with rotisserie color numbers of 9 to 11.
Feed containing 10 to 30 mg/kg of xanthophylls was fed to the animals. Therefore, conventionally, in order to obtain chicken eggs with pale yellow yolks, chickens during the laying period have been fed feed with a xanthophyll content of 1 mg/Kg or less for 3 to 4 weeks. [Problem to be solved by the invention] However, in the above method, the degree of color of the egg yolk is up to about 1 to 2 in terms of rotisserie color fan number,
It was difficult to obtain one with a value of 1 or less. Also,
There was a problem in that it took a long time of 3 to 4 weeks to obtain pale yolk chicken eggs. An object of the present invention is to solve the above-mentioned problems and provide a method for raising hens for producing pale-yolk eggs, which can produce pale-colored egg yolks with a lotus color fan number of 1 or less in a short period of time. [Means for Solving the Problems] In order to achieve the above object, the present inventors have conducted extensive research on factors that affect the color of egg yolk. As a result, they found that not only the xanthophylls in the feed, but also the xanthophylls contained in the body fat of the chickens themselves had a large effect on the color of the egg yolk. Therefore, with the conventional method of feeding feed containing less than 1 mg/Kg of xanthophylls during the egg-laying season, the chickens during egg-laying accumulate a lot of body fat in their bodies, including belly fat, so it is difficult to increase the amount of rotisserie color. 1.0 by number
It turned out that it was not possible to obtain a less pale egg yolk. The present invention was made as a result of the above research, and by reducing the amount of xanthophyll accumulated at the beginning of spawning as much as possible and feeding feed containing xanthophylls of 1 mg/Kg or less, it is possible to increase the lotus color fan number. This makes it possible to obtain light-colored egg yolks of 1.0 or less. That is, the method of raising hens for laying eggs with pale yolks according to the present invention is to feed the hens with a feed containing 1 mg/Kg or less of xanfil from the age of about 130 days to about 140 days, and to continue feeding them with this feed even after they start laying eggs. It is structured with this feature in mind. The other method of raising hens for laying eggs with light yolk eggs is to fast the hens during the laying period to reduce their body weight by at least 15%, and then reduce the xanthophyll content to 1.
It is characterized by refeeding less than mg/Kg of feed. The age of about 130 days to about 140 days corresponds to the late stage of growth, and during this period, the amount of body fat accumulated is small, and therefore the amount of xanthophyll accumulated in the body is also small, and the amount of xanthophyll does not increase thereafter. As a result, eggs enter the spawning period with a small amount of accumulated xanthophyll, and the conversion to light-colored egg yolk occurs quickly. This about 130 days old ~ approx.
The age of 140 days is adapted from the fact that there is a width of about 10 days for the start of spawning. for example,
If we assume that the time when 50% of the hens in the household start laying eggs is the time when they start laying eggs, then this time when they start laying eggs is approximately
The age ranges from 160 days to about 170 days. Fasting laying chickens to reduce their weight to at least approx.
The method of refeeding after reducing the number of birds after hatching is generally used for forced molting.
It is used as a method to rejuvenate old chickens after 500 days of age. In this method, if a person loses more than 15% of their body weight through fasting, their body fat will be almost completely reduced and the amount of xanthophylls will become extremely low. Feathers are then shed by refeeding, and egg laying, which had stopped, begins as the weight regains weight. Note that the body weight to be reduced is required to be 15% or more, but is preferably in the range of 20 to 25%. Therefore, spawning begins with a small amount of xanthophyll accumulated. Laying hens to which the breeding method of the present invention is applied include:
Chickens commonly used for egg-laying, such as white leghuon (Shaver Star Cross 288, Decaleb Excel Link, Highline W36, etc.), brown leghuon, Rhode Island Red, New Hampshire, and Nagoya. . The feed used for feeding laying hens in the present invention has a xanthophyll content of 1 mg/Kg or less. The feed ingredients may be any known feed for livestock, containing proteins, energy sources, calcium sources, phosphorus sources, vitamins, minerals, etc., and are formulated to satisfy NCR requirements. As a protein source, fishmeal,
These include soybean meal, rapeseed meal, feather meal, meatball mill, etc., and they contain DL-methionine, L-tryptophan, and L-methionine to compensate for amino acid imbalances.
Amino acids such as lysine and L-threonine may also be added. Energy sources include hydrocarbons such as corn, milo, and wheat flour, and fats such as feed oil, soybean oil, and powdered oil. Other phosphorus sources,
It goes without saying that it is necessary to contain vitamins, minerals, etc. in the same way as known feeds, and that the xanthophyll content of the above feed ingredients must be 1 mg/Kg or less. The content of ingredients is approximately 12-25% crude protein, 3-3% crude fat.
About 10%, calcium about 2.5-4.5%, ME2700
~3300Kcal/Kg is sufficient. An example is shown in Table 1.

【table】

〔Example〕

Example 1 From the age of 130 days, when the amount of body fat accumulation is low, and therefore the amount of xanthophylls accumulated in the body is small, feed with a xanthophyll content of 1 mg/Kg or less shown in Table 1 is fed, and from the time the animals reach 160 days of age. Start spawning (50
Egg laying was considered to have started when % of the chickens started laying eggs. ), and this feed was continued to be fed even after the start of egg laying. The egg yolk rotisserie color fan number associated with this feeding is shown below.

[Table] Example 2 Egg-laying chickens that have been over 400 days since hatching were
They were fasted for ~10 days with only water and no feed, and their body weight was measured during this period. When the body weight decreased by about 15% of the weight before the start of fasting, the xanthophyll content shown in Table 1 above was determined. Refeed less than 1 ft/Kg of feed. The amount of feeding started at 20 g per day and increased by 20 g each day. At this time, the egg-laying hens immediately stopped laying eggs after they started fasting, and when they were re-fed, they molted.
After refeeding, the animals started laying eggs when their body weights returned to about 90% of their pre-fasting weights. The egg yolk rotisserie color fan number associated with this feed is shown below.

[Table] The yolk of eggs that have started spawning becomes white from the beginning, and the degree of yolk color is rapidly increasing. Conventional Example 1 A 400-day-old egg-laying chicken was fed a feed having a xanthophyll content of 1 ft/Kg or less shown in Table 1 above and allowed to freely consume it. The egg yolk rotisserie color fan number associated with this feed is shown below.

[Table] - Fan number

Claims (1)

[Scope of Claims] 1. Laying of pale yolk eggs characterized by feeding a feed with a xanthophyll content of 1 mg/Kg or less from the age of about 130 days to about 140 days, and continuing to feed this feed after the start of egg laying. Breeding method for chickens 2 Fasting chickens during the egg-laying period to reduce their weight to at least approx.
After reducing by 15%, the xanthophyll content is 1mg/Kg
A method for raising hens for laying eggs with pale yolks, which is characterized by refeeding the following feed: