Diagnosis and treatment of b vitamin deficiency in chickens

The yellow-feathered breeder chickens and broilers raised by a company in Shenzhen were characterized by inward curling of chicken toe claws, paralysis of both legs, extreme bending of the head back in the shape of an angle bow ("stargazing" posture), dry and cracked skin, rough bifurcations of feathers and whitening of feathers. the hatching rate of breeding eggs decreased and the secondary seedling rate increased, which caused great losses to the production of breeder chickens and broilers in the company. After the therapeutic test, it was initially diagnosed as compound vitamin B deficiency, and the diagnostic process is reported as follows.

I. the process and symptoms of the disease

The company raises nearly 200000 sets of Shiqi hybrid yellow feather broilers and nearly 600000 commercial broilers. Due to the high technical level of the company's managers, the production performance has been maintained at a high level in recent years. In order to reduce the cost of feed production, the breeder and broiler feeds used by the company were prepared by ourselves, and all of them were mixed with imported or domestic monomer vitamins. Since the use of this self-made compound multi-dimensional premix for one month, a series of abnormal symptoms have appeared in breeder and broiler flocks. It was first observed that 30-160-day-old reserve breeder chickens had bifurcated and whitened feathers at the tip of the main wing and ailerons, especially in reserve cocks, and the proportion of white-feathered chickens was as high as 50%, while that of reserve hens was only 5% and 10%. With the passage of time, the proportion of white-feathered chickens has become higher and higher, and the degree of feathers from yellow to white has become more and more obvious. Some reserve cocks and even most of the body's feathers have turned white. At the same time, 5% or 10% of the reserve chickens had dry, burst and bleeding skin between their toes, and 1% or 2% of the chickens had their toe claws curled inward and their legs paralyzed. At this time, laying hens and breeder cocks also have similar symptoms, but the incidence is slightly mild. Subsequently, 10% to 30% of the chickens within 30 days of age had dry, bursting and bleeding skin between their toes, 1% to 2% of the chickens had their toe claws curled inward, and 5% of the chickens showed whitening of the main wing feathers and ailerons.

Although a small number of laying hens have white feathers, the egg laying rate has not decreased significantly, and the fertilization rate of breeding eggs has not changed significantly, but the hatching rate has decreased slightly (1% / 2%). In particular, the healthy seedling rate has decreased by 5% to 10%, and the residual seedlings have gradually increased. The mortality rate of the chicks who have arrived at the broiler farm within one week has reached more than 5%, with the highest reaching 20%. 1% to 2% of the chickens hatched by breeding eggs in the later stage of the disease showed a "star-watching" posture, with their heads extremely bent to the back, showing an inverted horn bow, or tilting their heads to one side or turning their heads in circles, and their legs were paralyzed and unable to stand and walk. The sick chickens landed on the ground with their hocks and tails, sitting on the ground or lying on their sides.

Because the compound multidimensional premix used in the company's broiler farm is also prepared by ourselves, so the chickens in the company's broiler farm have similar symptoms: 10% or 30% of the chicks within 30 days of age have dry intertoe skin, bursting bleeding, growth retardation, loss of appetite, dishevelled and dull feathers, weak legs and unstable gait; 1% of the chicks have toe claws curled inward. Among the Chinese chickens over 30 days old, 5% of the hens and 30% of the cocks turned white, and 5% of the cocks had dry and burst intertoe skin. and with the longer the use of this feed, the more obvious the symptoms of white feathers and intertoe bursting bleeding, the higher the occurrence rate.

Second, pathological changes

There was no obvious pathological change in sick and dead chickens.

III. Diagnosis

1. Microbiology and immunological diagnosis: the blood samples of diseased chickens (including breeder chickens and broilers) over 30 days old showed that the antibodies against Newcastle disease, infectious bronchitis and infectious bursal disease reached a high titer, and the pathogenic virus was not isolated from the heart blood, liver and spleen of diseased chickens and diseased chickens. The related bacteria were not isolated from the heart blood, liver and spleen of dead chickens and diseased chickens inoculated with McConkey medium, common Agar medium and blood Agar plate respectively.

two。 Therapeutic diagnosis: before making the preliminary diagnosis of suspected B vitamin deficiency, the company had used up the feed of self-made multi-dimensional premix and replaced the previous multi-dimensional feed with Roche 438 dimensions. therefore, the author is unable to send and analyze the original self-made multi-dimensional premix and compound feed composition. After changing the multi-dimensional premix for more than half a month, the production of breeder and broiler flocks gradually returned to normal. In this paper, 900 1-day-old residual chicks hatched from breeding eggs after the onset of the disease were divided into 9 groups with 100 chicks in each group, except for group 1 without using any drugs as control. The other 8 groups were treated with vitamin B1 (10 mg / time), B2 (2 mg / time), pantothenic acid (200 μ g / time), nicotinic acid (15 μ g / time), B6 (10 mg / time), folic acid (100 mg / time), B12 (0.5 μ g / time) and compound vitamin B (10 μ g / time).

The rats were injected once a day and the incidence of each group was observed after continuous injection for 5 days. The results showed that the symptoms of chicks injected with vitamin B1, B2, pantothenic acid, folic acid and compound vitamin B were alleviated in varying degrees, and the chicks injected with compound vitamin B had the best recovery. Therefore, the preliminary diagnosis of the disease is B vitamin deficiency, rather than a single vitamin deficiency.

IV. Discussion

1. Because the technological process of the company's preparation of multi-dimensional premix adopts simple monomer vitamin mixing production according to the indicated quantity, which leads to the decrease of the effective components of some B vitamins, coupled with the hot weather during the onset of the disease, it is possible that the improper preservation of raw materials may reduce the titer of monomer vitamins and multidimensional premix, these factors may be the main causes of this disease.

two。 The disease of breeder chickens and broilers showed typical symptoms of vitamin B2 deficiency characterized by inward curling of toe claws and paralysis of both legs, and typical symptoms of vitamin B1 deficiency characterized by "stargazing" posture in chicks. Typical symptoms of pantothenic acid deficiency characterized by dry, burst and bleeding skin And the typical symptoms of folic acid deficiency characterized by growth retardation, poor feather growth and lack of pigment (feather whitening) in chicks and middle chickens, and it was also proved by therapeutic experiments that the disease was B vitamin deficiency dominated by vitamin B1, B2, pantothenic acid and folic acid.

3. The disease had little effect on egg laying and fertilization of laying hens, which may be due to the fact that the amount of compound multi-dimensional premix in the feed of laying hens and cocks was twice as much as that of reserve breeders and broilers. In spite of this, it still has a certain effect on the hatching of breeding eggs (the hatching rate of hatched eggs is reduced by 1% / 2%), and the healthy seedling rate of hatched chickens is reduced by 5% / 10%, and the early mortality rate of chicks is increased to 5% / 20%, which seriously affects the quality of chicken seedlings. If you do not add B vitamins in time, it will affect the growth performance of broilers, and even show various symptoms of deficiency. The follow-up investigation on the broiler farm of the company also shows that if the chicken feed is supplemented with multivitamin B powder or multidimensional premix, or drinking water with multivitamin B solution or water-soluble multidimensional premix, the disease can be obviously alleviated, the death rate can be reduced and the production performance can be improved.