Combatting Oxidative Stress with Vitamin C
Introduction
In the most simplistic terms, the body can be compared to a medium in which millions of chemical reactions take place with the support of food energy. These reactions are the basis of life, without which life would cease to exist, and they all require oxygen to maintain proper function. For this reason, oxygen can be considered the fire of life; it can never be burnt out of control or be exstinguished completely. Our job is to optimize its use in humans and animals.
Oxidative stress occurs when reactive metabolites of oxygen – known as reactive oxygen species or free radicals – exceed what the body can dispose of safely. These include singlet oxygen, superoxide, hydrogen peroxide and both hydroxyl and fatty acid radicals, all of which can react with enzymes, cell membranes and DNA, damaging them or causing cell death (aging).
In animal production, these free radicals may occur as a result of physical, biological and chemical stressors and can result in reduced production, morbidity or mortality. Dairy cows, for example, can develop health disorders related to oxidative stress, including retained fetal members, udder edema and mastitis. Milk quality and shelf-life can be affected by lower levels of the antioxidants vitamins A, C and E. Pre- and post-weaning periods can also stress dairy calves due to changes in diet; premature development of the rumen in these calves often results in reduced vitamin C synthesis, precipitating a reduction in total antioxidant capacity. All of this results in a depressed immune function that predisposes cows to infection by deadly pathogens.
Cellular defenses to control or neutralize the harmful effects of free radicals are naturally occuring in the cow through:
- Enzymatic neutralizing defenses (Zn/Cu/Mn superoxide dismutase, Fe-catalase, Se-glutathione peroxidase and Se-glutathione-S-transferase)
- Enzymatic damage repair defenses (lipases, proteases and DNA/RNA repair enzymes)
- Non-enzymatic defenses (glutathione, uric acid, melatonin, hypotaurine)
- Nutrient defenses (carotenoids, ascorbate, tocopherols, tocotrienols, phenols, lycopenes, trace minerals, etc.)
But in our experience, the most efficient approach to controlling oxidative stress in animal production is with nutrient defenses or antioxidant supplementation.
Dairy Cow Study
At Maxx, we studied the use of microencapsulation technology to produce a stabilized vitamin C that, when used as a supplement in animal feed, is resistant to extreme temperatures and low pH levels, protected from microbial degradation and biologically available to all ruminants and nonruminants.
We contracted with an outside laboratory to evaluate the stability of microencapsulated ascorbate, or vitamin C, in the rumen of cows using in situ procedures and ruminally cannulated dairy cows. Samples were tested for digestibility using high producing lactating dairy cows in mid-lactation. The cows were fed a standard dairy cattle ration balanced according to NRC recommendations. Ruminal incubation lasted 16 hours to simulate expected retention times for products of this type. A second 48-hour incubation was conducted to estimate total ruminal digestibility.
The coating material was not filtered or washed out of the in situ bags during the soaking or washing procedures. The coating also showed evidence of only minimal ruminal degradation after 16 hours of in situ ruminal incubation.
The analysis showed that after 16 hours of incubation, about 88% of the ascorbic product had not degraded in the rumen; after another 48 hours, 81% had not degraded. Since these are dry matter disappearances, we do not know the exact level of bypass. The worst case scenario is that all of the dry matter disappearance is the coated nutrient. This then would give a rumen bypass of about 77% for the microencapsulated ascorbic acid.
The case for microencapsulated Vitamin C
Microencapsulation delivers rumen stable Vitamin C. Additionally, the technology allows ascorbic acid to be physically protected from air, light and metals, thus maintaining its potency, whereas unprotected and non-microencapsulated vitamin C supplements are exposed to temperature, pH and air destruction before they are needed.
Microencapsulated Vitamin C also represents a powerful stress-reducing agent. It participates in the intracellular and extracellular quenching of reactive oxidants, the recycling of vitamin E (electron transfer to oxidized tocopherols and tocotrienols), serves as a co-factor in eight major essential enzymatic reactions, prevents LDL oxidation, and promotes iron absorption in the gastrointestinal tract. Thus, vitamin C is more than an antioxidant – it supports a multitude of essential chemical reactions the body needs to thrive.
Microencapsulated Vitamin C should be supplemented to reduce the stress of production in all animals – and also generate efficiencies. Microencapsulated ingredients are more cost effective compared to the cost of overdosing nutrients, and overdosing still does not prevent the loss of unstable nutrients such as Vitamin C.