Selenium (Se) is a vital nutrient of fundamental importance in humans and animals biology. Se is key for the ideal functioning of male fertility, freshness of egg, embryo development, control of aflatoxin B1 (AFB1) and immune, productive and reproductive systems.
It also provide defense against infections, tumors and in inflammatory conditions in both humans and animals.
The suitable level of Se is important for chicken health, productive and reproductive characteristics (embryonic development and sperm quality) and optimal functioning of immune system.
Organic (selenomethionine) and inorganic (selenite or selenate) are 2 major sources of selenium. Se is feed derived natural antioxidant in poultry.
Selenium and AFBI
Se provide protective effects against various toxic agents. Exposure to AFB1, induced liver dysfunction by disturbing the tissue enzyme activity and enhanced apoptosis, but the Se protected liver tissues against AFB1-induced toxicity.
Dietary Se provide protect from AFB1-induced liver injury by inhibiting CYP450 enzyme, which is responsible for the activation of AFB1 to toxic AFBO.
It can also alter immunosuppression effects induced by AFB1 in spleen of Broiler.Se has ability to enhance immunity by affecting the metabolism of carcinogens through the formation of anticancer metabolites.
Se or reactive Se metabolites prevent the binding of DNA with carcinogens can render the carcinogens into non-carcinogenic.
Selenium and embryo development
Antioxidant (Se) increase in the maternal diet can significantly increase their concentrations in developing chick tissues and decreases their susceptibility to lipid peroxidation.
Selenium concentration in newly hatch chicks as follow:
Liver > kidney > lung > heart > brain > muscle.
Therefore it is suggested that brain lipid composition and antioxidant concentrations affect this tissue by lipid peroxidation which leads to development of nutritional encephalomalacia with low vitamin E and Se concentration.
The Se content of the egg depends on its concentration in the hen’s diet and dietary Se used. So, Se in the egg is transferred to the developing embryo during incubation. Organic Se is more competently deposit in the egg yolk.
Selenium and male fertility
The source of selenium in the diet of male birds is of great importance. Because hydrogen peroxide and lipid peroxides are toxic to Spermatozoa.
It is important to note that the Se-dependent form of GSH-Px (glutathione peroxidase) comprised 77.7% (chicken) of total enzymatic activity.
GSH-Px is the main enzyme removing peroxides and protecting sperm cells by damage free radicals. Distribution of this enzyme between spermatozoa(40%) and seminal plasma(60% ).
So, diet containing Se and tissue Se reserves are main factors for maintenance of GSH-Px activity and protection against lipid peroxidation. Organic Se is beneficial in maintaining fertility in final-stage laying hens.
Selenium and diseases
Increased Se supplementation have an immune stimulating effect. Selenium supplementation at 0.4 mg/kg for White Leghorn type chickens reduced death or lesions from E. coli.
Similarly, increase Se level in diet (0.6 mg/kg) decrease morbidity and mortality of broilers from Marek’s disease and infectious bursal disease.
Dietary Se between 0.1 and 0.8 mg/kg significantly (77%) increased antibody titres. Inhibition of T-lymphocytes tranformation due to infection is less in Se supplemented birds.
Se requirement for immune function is much higher than the requirement to maintain growth and development.
Se and egg freshness
- Egg freshness is one of the most important parameters of consumer perception and demand.
- Egg quality decreases during storage.due to biochemical changes in composition and in structure of egg.
- Use of selenomethionine in the layer diet increase GSH-Px activity in the egg yolk and white which maintain egg quality during storage.
- Se supplemented birds have more haugh value which is use for determine the egg freshness.
Se and meat quality, broiler performance
Increase GSH-Px activity in breast and leg muscle by adding Se in broiler diet and decrease lipid peroxidation.
Absence of tissue Se reserves (inability to synthesize additional selenoprotein)
Stress condition >>>>> overproduction of free radicals and lipid peroxidation >>>>> decrease productive and reproductive performance, increase susceptibility to disease.
Presence of tissue Se reserve (ability to synthesize additional selenoprotein)
Stress condition >>>>> selenoprotein production and prevention of lipid peroxidation >>>>>maintenance of high productive and reproductive performance and resistence to diseases.
Authors: Muhammad Hammad Akhtar*1 , Anuam Akhtar1
1 Department of Pathology, Faculty of Veterinary Science, University of Agriculture Faisalabad.
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