Controlling oxidative stress in pigs

Oxidative stress is caused by different high stress conditions such as antibiotic treatments, heat stress, weaning, high animal densities and periods of peak technical performance. As a result, excess free radicals (unstable molecules or oxidants, mainly reactive oxygen species) are formed. Those attack and injure vital body cell parts such as membrane phospholipids, mitochondria and DNA structures. This impaired functioning, leaking or even death of cells on a systemic scale creates important energy losses to the animal. Hence, an imbalance between the level of endogenous antioxidants (from the animal itself) and the level of generated free radicals can affect the integrity of all body cells and thus cause suboptimal animal performance.

Controlling the pig’s body maintenance

Most bioactive antioxidants (like vitamins E and C, selenium) are primarily used in the diet to fulfil the specific nutrient requirements of the animal. However, powerful selected antioxidants are able to efficiently minimise the animal’s body losses due to cellular oxidation and establish a balanced energy metabolism status, “energy homeostasis.”

Elife is a particular blend of natural antioxidants with specific chemical properties. Different studies revealed that its active ingredients reinforce each other via multiple modes of ­action within the animal’s body:

• By scavenging (neutralisation) of free radicals both intra- and extracellularly;
• By regenerating (recycling) used antioxidants in vivo, such as vitamin E; and
• By upregulating the biological synthesis of endogenous antioxidants.

Thanks to those different antioxidant mechanisms, dietary supplementation with the blend alleviates oxidative stress and decreases the pig’s body maintenance requirement. Less metabolic energy is drained by oxidative cell damage and more becomes available for optimal organ functioning, (lean) muscle tissue growth, digestive processes, etc.

In multiple field trials, supplementation with the natural anti­oxidant blend in the diet of fattening pigs resulted in a consistent improvement in live body weight at slaughter, as shown in Figure 1. That empirical overview represents a variety of very different external factors (farm, diet, time, genetics, stress level) under which pigs were commercially grown.

Figure 1 – Summary of a blend of natural antioxidants* in improving final weight of fattening pigs (based on 13 consecutive trials or in total 7,294 animals raised under commercial conditions).

^{Click here for enlarged image}

Oxidative stress affects the carcass

Pigs under substantial oxidative stress deposit more fat and less protein in their body tissues such as muscles. In numerous trials, supplementation of the diet with the blend of antioxidants has shown to yield a higher hot carcass weight (in line with an improved final live weight) and loin meat thickness (longissimus dorsi muscle), as clearly shown in Figure 2. Those observations confirm the parallel observations of a reduced feed conversion ratio, which usually indicates less build-up of body fat depots (as slaughterhouse wastes) and more deposition of muscle protein (meat).

Figure 2 – Hot carcass weight and loin meat thickness of experimental fattening pigs.

^{Click here for enlarged image}

The endogenous antioxidant system

All cells have a well-developed endogenous defence system against reactive oxygen species, which assists in limiting their formation as well as instructing their removal. Within a body cell, superoxide dismutase (SOD) constitutes the first line of defence against free radical attacks. Once peroxides intermediates are formed after the intervention of SOD, glutathione peroxidase (GPx) in its turn is a major peroxide scavenging enzyme, turning harmful peroxide into water.

Liver tissue sampled from fattening pigs supplemented with the blend of antioxidants displayed a higher antioxidative protection compared with control animals. That occurs by means of a higher SOD level as well as by an important increase in GPx activity of hepatic cells, as illustrated in Figure 3. Such an improved antioxidant capacity of the animal further proves that the dietary natural antioxidant blend reduces the level of oxidative stress within fattening pigs, thereby limiting cellular damage and eventually increasing technical performance and economics.

Figure 3 – Liver antioxidant capacity of experimental fattening pigs.

^{Click here for enlarged image}

Targeted control of oxidative stress

Targeted control of in vivo oxidative stress is crucial to obtain more sustainable pig production. Various field trials under different stress conditions have proven that supplementation of a natural antioxidant blend (Elife) in the diet of fattening pigs brings important economic benefits to both commercial pig farmers and pork meat integrators. That is of particular importance during challenging periods of scarcity of input resources, in which more animal protein should be produced with less. A recent example is the rapid spread of the African Swine Fever virus worldwide, which reduced the sow herd size in swine production systems significantly and thereby also the number of marketed fattening pigs or total pork meat ­supply.

References are available from the author upon request (elife@impextraco.com).