Acute phase proteins pertain to biological macromolecules that are inherently situated in the blood. The amount of these proteins fluctuates in response to a particular physiological condition such as infection (Lampreave et al. , 1994). These proteins are also indicative of inflammation, which is associated with lesions in particular tissues and the shedding off of marker proteins in the circulating blood. Examples of acute phase proteins that increase in concentration during infection are serum amyloid A (SAA), as well as C-reactive protein (CRP).
In addition, the levels of major acute phase protein (MAP) and haptoglobulin (Hp) proteins in the blood were also reported to be at a higher concentration in mammalian species during infection (Lipperheide et al. , 1998). On the other hand, the acute phase proteins such as albumin and ? -lipoprotein decrease in concentration among mammals during infection. It has been reported that a certain fraction of animals brought into the slaughterhouse have elevated acute phase protein levels, indicative of an active infection or inflammation (Steel and Whitehead, 1994).
The situation is further complicated as these animals are slaughtered and subsequently distributed to markets for sale to the general public. The presence of bacterial infection may thus pose a health risk to the consumers and this may possibly result in an epidemic. It is thus important to regularly screen the animals that are brought to the slaughterhouse in order to monitor any impending infection that may be transmitted to humans. The concept of infection and inflammation in animals such as pigs and cattle are of prime importance to the general public as this provides an idea of the situation of these animals.
Aside from the risk of the consumer of receiving the pathogen that is present in the meat of the animal, the presence of infection or inflammation in the animal reflects the type of condition that the animal was living in. Inflammation is strongly associated with the occurrence of lesions in particular areas of the animal’s body and this may be the result of poor hygienic conditions in their place of origin (Pedersen and Dahl, 1995). It may also be possible that the quality of the air in the breeding place of these animals was substandard, resulting in either an increase or decrease in levels of the protein markers in the blood.
The technical application of screening for acute phase proteins in the blood of animals brought into the slaughterhouse for subsequent marketing may thus serve as an important tool in determining safety of the meat derived from these animals. It should be understood that any deviation from the normal range of specific plasma proteins may indicate that the animal has developed a clinical condition that may be harmful to both the animal, the animal handler, the meat cutter, and ultimately the consumer.
The application of screening for acute phase proteins may thus ensure the safety of meat products, as this will identify which animals are suffering from a particular disorder. Another benefit of the application of screening for acute phase proteins in the blood of animals is the increase in the production of quality meat, as the animals that are sickly or showing any signs of infection are spared from being slaughtered and possibly isolated from the rest of the animals.
The presence of an infection in one animal can result in the inoculation of the entire herd and thus the active screening of acute phase proteins may save the farmer extra expenses in transporting and processing the meat of these animals when they are aware early on the infection. In Europe, the screening of acute phase proteins in animals has been required in animals that are brought into the slaughterhouse. There are also active efforts in the standardization of immunodetection assays for each species, as different procedures and protein levels may be present for each.
Acute phase proteins are generally considered as macromolecules that play a role in the immunity of an organism (Mackiewicz et al. , 1993). These proteins activate specific cellular components that serve as the frontline immune response towards invading materials and pathogens of the body. Acute phase proteins may aggregate bacteria that are present in the blood and this allows its identification and presentation to macrophages. In turn, macrophages either produce antigen-specific antibodies or release proteolytic enzymes that will destroy the cell membrane of the bacteria and ultimately result in its death.
Acute phase proteins can also entrap specific enzymes that are harmful to the animals, as well as collect free radicals that may result in membrane damage in tissues. Acute phase proteins are synthesized in the liver, which in turn are released into the bloodstream for further circulation. These proteins are activated by the presence of cytokines, which are ligands that indicate a proinflammatory condition in an animal. Cytokines can thus be considered as the initial response of the body to any form of injury or inflammation and the marked increase in its concentration in the blood is a direct effect of the condition.
Aside from its ability to activate acute phase proteins, cytokines increase the rate of metabolism of an animal. This would result in the increase in energy expenditure and possibly a change in the appetite of the animal (Schrader and Ladewig, 1997). The effect on the body of the animal will be obvious if the amount of food consumed is significantly smaller than normal, resulting in the weight and meat mass of the animal. The identification of clinical conditions in animals through the screening of acute phase proteins in the blood is thus an important procedure that has several benefits.
Meat quality and safety is the direct outcome of this procedure, while the secondary effects include prevention of further contamination of other animals and the improvement in the living conditions of these animals. The use of acute phase proteins in determining diseases in animals may thus allow animal breeders to monitor the conditions of their animals and provide them clues on whether a particular treatment or procedure should be performed.