Effects of vitamin A on animal husbandry

Vitamin A is an essential vitamin for humans and animals, belonging to the fat soluble vitamin, it is known that vitamin A can maintain the normal vision of animals, and it also plays a very important role in maintaining animal body development, epithelial growth and differentiation, reproduction and bone development. In addition, vitamin A is an important member of the non-enzymatic antioxidant defense system. It is located in cell membranes and protects cell membranes by scavenging free radicals and peroxides, Avoid Lipid peroxidation by enzymatic or non-enzymatic reaction of polyunsaturated fatty acids (PU -- FA) under the action of free radicals and produce lipid peroxide (LP0). Palacios(1996) et al. proved that vitamin A was an effective antioxidant and free radical scavenger in vitro experiments. [1] Therefore, the role of vitamin A is particularly significant in animal husbandry.

Vitamin A deficiency results in stunted growth in all animals. Vitamin A deficiency in pigs results in neurological disorders, hydrocephalus, peripheral neurodegeneration, dyskinesia, staggering gait, tonic spasms and paralysis of the limbs. Dry eyes, reduced vision or blindness. Large pig skin epidermis dry, keratosis increased drama, rough fur, some seborrheic dermatitis. Often secondary respiratory tract infection pneumonia and death. [2]

The spirit of the bird is weak, the appetite is poor, the body is emaciated, the feathers are disjointed and lose luster, and the wattle and comb are pale. The eyelids become dry and watery, and there is a watery discharge from the eyes and nostrils. The discharge will glue the upper and lower eyelids together, and there are varying amounts of caseous milky substance accumulated in the eyes. A few may even present the symptoms of keratitis. [3]

Ruminants have decreased appetite for feeding, disordered fur, slow growth and development, gradually wasting body, dysplasia, arrhythmia, anterogastasis, rumen distension, and persistent watery watery stool, obvious eyelid edema, eyeballs protrusion outward, pupil dilation, unable to retreat after strong light stimulation, and slow action in the farm. [4]

When fish lack vitamin A, there will be photophobia, exophthalmos, cataracts, retinal degeneration and other symptoms, but also cause fish growth delay and fin bleeding phenomenon. [5]

However, the use of vitamin A must also meet the maximum limit standard. Vitamin A is the most toxic vitamin among all vitamins. Only reasonable compliance in the use process can ensure stable production performance. Chronic or sudden ingestion of excessive vitamin A can cause animal poisoning. For non-ruminants and poultry, the toxic dose of vitamin A is 4-11 times of the required amount, and for ruminants it is 30 times of the required amount. Vitamin A poisoning can manifest as bone malformations, organ degeneration, slow growth, weightlessness, skin damage, and congenital malformations. Pig poisoning shows rough coat, sensitive touch, blood in feces and urine, trembling, and eventually death.

It should be noted that when other diseases occur in livestock and poultry, the requirement for vitamin A will also increase. For example, when laying hens suffer from bronchitis and gastroenteritis, the body's own vitamin A requirement will increase by 2 to 4 times, that is, at this time, we should pay attention to the timely supplement of vitamin A in feed, so as to ensure that the needs of the body can be met. [6]