First, the harm of zinc deficiency in dogs
1. Growth is hindered
As a constituent element of a variety of metalloenzymes, zinc intervenes and regulates cellular metabolism in the body. Zinc deficiency weakens the dog's sense of taste, smell, affects appetite, and can also constrain nucleic acid, protein composition and cell division rate, so that the body is slow to grow slowly, weight loss is significantly reduced, and its descendants will also be significantly lower than other dogs due to continued zinc uptake reduction. Short-term constrained zinc intake will cause downregulation of the expression of genes related to osteoblast production in rats, while long-term constrained zinc intake will affect the body's calcium homeostasis, which will hinder the composition of bones.
2. Hindrance to reproduction
Zinc deficiency causes pregnant mothers to suffer from pregnancy complications, increases the risk of miscarriage and deformed fetal birth in pregnant dogs, and affects the normal gonadal function of male offspring, resulting in poor testicular development, cryptorchidism or abnormal sperm. Zinc deficiency will cause the levels of progesterone and cortisol in the liver of pregnant mice to be out of balance, which can cause the level of estradiol in the liver of male fetuses to rise, and the embryo will eventually cause reproductive obstruction due to the long exposure of the androgen deficiency environment. Zinc deficiency not only affects the process of sperm energization and apical response, but also significantly reduces the volume of testicles in mice, reduces the number of sophisticated sperm, and triggers apoptosis.
3. Decreased immunity
Zinc deficiency weakens the phagocytic abilities of mononuclear macrophages and exacerbates their apoptosis. Clinical cases have shown that hypozincemia in dogs with lymphocytic plasma enteritis may aggravate gastrointestinal inflammation in dogs, affecting their prognosis and survival time. At the same time, zinc deficiency inhibits fibroblast growth and slows wound healing.
4. Impaired neurodevelopment
Zinc deficiency in pregnant or nursing female dogs will harm or delay embryonic neurodevelopment, resulting in the development of the hippocampus and amygdala, cerebellum and neural stem cells of the brain, and the expression of decomposition-related genes is downregulated, so that the puppies' cognition and recall can be reduced, and the intellectual development is slow. The Morris water maze experiment found that the spatial recall and localization of the offspring of zinc-deficient pregnant rats were significantly worse than those of the offspring of normal pregnant rats. The disruption of zinc homeostasis will also induce neurodegenerative diseases, so that the brain constitutes amyloid precipitation, and the body's internal environment will have local zinc deficiency symptoms due to the abnormal aggregation of zinc in protein-like plaques, resulting in microglia and astrocyte activation, and eventually causing brain cell death and neuroinflammation circles.
Second, the cause of zinc deficiency in dogs
1. Genetic elements
Certain Arctic breeds of dogs, such as Siberian sled dogs, Alaskan dogs, etc., are at risk of zinc transporter mutations at any age due to genetic shortcomings. Even if the diet of such dogs is rich in zinc sources, zinc deficiency may occur due to the body's ability to absorb or metabolize zinc weakly compared with other dog breeds. There have also been clinical statements that non-Arctic breed dogs, such as the Boston Terrier, may exhibit zinc-specific zinc-resilient skin diseases specific to Arctic breed dogs due to zinc deficiency, even if they differ from Arctic breed dogs in their genetic risk of zinc transporter mutations.
2. Dietary elements
Zinc deficiency in dogs is very rare simply formed by daily diet, and zinc deficiency in dogs is often affected by a variety of factors: pet food animal protein source test results do not match the product label; the nutritional content of homemade dog food is unbalanced; the owner does not adjust the dog food according to the prescription of the doctor; feeding grain-based dry feed, increasing cheap meat or other ingredients, so that the amount of zinc deficiency in the diet or zinc can not meet the body's long-term nutritional needs, etc., there is a chance to induce zinc deficiency in dogs. Second, food ingredients can affect the bioavailability of zinc, such as phytic acid can form an insoluble complex with zinc, so that zinc intake is restricted. Studies have found that the serum and femur content of rats with low phytic acid diet is higher than that of rats with high phytic acid diet.
3. Effect of zinc with other trace elements
The mutual effect between trace elements will affect zinc absorption, and trace elements with similar structure to zinc will even compete with zinc for binding sites, reducing the body's bioavailability of zinc. The study found that the prolonged use of ferrous sulfate, calcium carbonate or a combination of compensatory agents led to a significant decrease in zinc concentrations in the serum, liver, kidneys and spleen of rats. Compensating for chromium in an iron-deficient diet can lead to a significant decrease in the amount of zinc in the spleen. Some trace elements inhibit the expression of zinc in the body through transporters. For example, at low blood selenium, the activity of glutathione peroxidase decreases, and the release and transfer of zinc in the body is hindered.
4. Diseases and drugs
The four types of diseases, diarrhea, renal insufficiency, inflammation, and infection are often potential signs of zinc deficiency. It has been stated that blood zinc concentrations in dogs with abnormal behavior will be significantly lower than in normal dogs. Dogs with developmental bone diseases such as the medial coronary process also have low hair zinc levels. In addition to the effects of the disease, the use of drugs (such as penicillinamines, tetracyclines) or metal chelating agents can also induce zinc deficiency. Clinically, patients with primary hypertension with monotherapy with diuretics, Ca2+ antagonists, and angiogenerin-converting enzyme inhibitors present with decreased red blood cells or/and serum zinc concentrations.
Third, the study of zinc supplement preparations
1. The effect of zinc supplementation preparations
Zinc supplements can be used as protective agents in models of neurological disease treatment. Compensating zinc preparations when hyperthermia induces epilepsy production can improve the body's tolerance to epilepsy, prolonging the incubation period of epilepsy. The use of the anti-epilepsy drug Valproicacid (VPA) alone causes moderate liver damage and triggers portal vein inflammation, while the combination of zinc sulfate and VPA presents only mild portal vein inflammation. Zinc supplementation as an adjunct to VPA alleviates zinc deficiency and liver oxidative damage caused by the use of VPA.
Zinc supplements can also be used as functional nutritional supplements for special age groups to regulate zinc homeostasis in the machine. In addition, zinc supplementation has a positive effect on the reproductive ability and neurodevelopment of test animals. Healthy dogs with extra zinc in the diet have increased their motility and motility. Abnormal behavior in pet dogs, such as hyperactivity, sudden panic tremors, and aggressive behavior, can also be prevented and improved with the use of zinc supplements.
2. Types of canine zinc supplementation on the market
There are three main types of zinc supplements available for dogs on the market, namely inorganic zinc, organic zinc and bio-zinc. Inorganic zinc, such as zinc sulfate (ZnS), zinc oxide, etc., can be used as a daily zinc source to make up for the daily zinc needs of dogs. Organic zinc such as protein zinc (0Z), zinc gluconate (ZnG) and various amino acid zinc can be used as a dietary zinc source or as a clinical drug. Compared to the inorganic zinc source in dog food, 0Z is less likely to interact with other dietary ingredients, and then improve the body's bio-profit cost of other elements such as phosphorus.
In the treatment of canine atopic dermatitis, long-term supplementation of zinc methionate can reduce the frequency of administration of glucocorticoids or cyclosporine, reduce the index of canine-specific dermatitis lesions and the degree of skin itching, and have a potential therapeutic effect on mild to moderate and non-seasonal, chronic specific dermatitis. The amino acid zinc can effectively improve the coat quality of puppies and improve the efficiency of the body's use of nutrients such as protein. Bio-zinc is mainly zinc-rich yeast (ZnY). Increasing ZnY in the diet can improve the bio-benefit cost of zinc, which together reduce the occurrence of adverse reactions. The study showed that the bio-benefit cost of ZnS, ZnG and ZnY in the body is not obvious, but zinc-rich yeast is simpler to absorb and secretes less zinc.