March 3, 2023


APC's Dr. Joe Crenshaw: Armouring pigs' defense against diseases with plasma


An eFeedLink Exclusive Talk


APC, a global leader in functional proteins, started in 1981 following the discovery of the advantages plasma-derived functional proteins offer to better support and maintain animals' immune function, according to the company's history.


Today, APC's chief expertise lies in obtaining blood from healthy animals at pork and beef slaughter plants, with the blood used to create spray-dried plasma. This feed ingredient contains highly digestible proteins and amino acids, as well as high concentrations of functional bioactive elements like immunoglobulins and transferrin.


Plasma protein is the cornerstone of APC's business, and a "unique ingredient when compared to other protein sources," Dr. Joe Crenshaw, APC's vice president of technical service, tells eFeedLink.


Dr. Joe Crenshaw, APC's vice president of technical service


The company has 17 production facilities in 8 countries (primarily in North America, South America and Europe) and sells its products in over 58 countries. "We have a presence in the Asia-Pacific including China, Japan, Philippines, Thailand, Vietnam, South Korea and Taiwan, for many years," Dr. Crenshaw adds.


He says that plasma has been used "for over 40 years in pig diets," and refers to a multitude of studies attesting to its significant role in pig health.


At this year's VIV Asia show in Bangkok, Thailand, Dr. Crenshaw will highlight plasma's strengths in the presentation, "Plasma improves ASF vaccine efficacy."


Plasma for pigs in disease-challenged times


At the current juncture in livestock production's history, increased restrictions or bans on using antibiotics and zinc oxides have seemingly limited the options for protecting and improving animal health. Meanwhile, threats of a pathogenic nature loom on the horizon: African swine fever (ASF) and avian influenza, for instance, have grabbed headlines of late.


"We are going to have ASF around for a while; it's not going to quickly go away," Dr. Crenshaw says. ASF outbreaks are expected to happen from time to time in an endemic situation. Pigs in tropical regions are especially vulnerable during rainy seasons; ASF infected wild pigs can spread the ASF virus to surrounding water areas, escalating the pathogenic exposure that domestic farm pigs face.


"Once ASF gets into feral pigs, it's hard to prevent it from getting to the domestic pig population. It's going to take a longer-term effort through common biosecurity measures and minimising human movements around pigs," Dr. Crenshaw advises.


Taking ASF into consideration, he points to the benefits of plasma in shoring up a pig's defense against diseases.


However, Dr. Crenshaw acknowledges that plasma can be considered costlier than other proteins when "just looking at feed costs alone." Understanding how it is efficiently used is key to achieving favorable outcomes in a cost-saving manner. It should also be noted that plasma constitutes a "very small percentage of total feed needed to produce a market weight hog."


"You have to look at the feeding duration and level of plasma in the diet to maximise the economical aspects (of feeding)," Dr. Crenshaw states. "(Based on our studies), we may need to target around 300 grams of plasma per pig in the nursery phase (to achieve heavier pigs at slaughter). This comes down to the type of feeding programme used and the phases (of pig production, during which plasma is involved). It also depends on how healthy the pig is."


He suggests using a "simpler diet with plasma" can be a more preferable option to "more complex diets without plasma."


Highlighting plasma's utility in "promoting animal health and the animal's immune system," he notes that it can boost pigs' growth, especially after weaning. Additionally, pigs infected with bacteria or virus pathogens and fed plasma have less severe symptoms and recover more quickly.


"We have published over 600 peer-review studies concerning feeding plasma to mostly swine as well as other species (of animals)," says Dr. Crenshaw. "When comparing plasma to, for example, fishmeal and milk proteins, we consistently see increases in growth rate and feed intake in pigs, particularly, in the 14 days or so after weaning. We have used plasma in sow diets and have seen improved weaning weights."


"(Weaning) is when plasma is usually applied," he adds. "Compared to other protein sources, none can compare to what (spray-dried) plasma can do."


How does plasma fare in a situation involving an outbreak? According to Dr. Crenshaw, the incidence of mortality drops when pigs are fed diets supplemented with plasma.


"We saw better survivability (in pigs)," he says. "We challenged the pigs with, for example, E. coli and other types of pathogens, and observed that when pigs fed with plasma were faced with such challenges, they experienced less diarrhea and suffered fewer effects of the disease. They seemed to recover a lot quicker."


In yet another study, the stakes were raised with the introduction of the ASF virus.


"Non-vaccinated pigs fed diets with or without spray-dried porcine plasma were exposed to pigs infected with ASF" Dr. Crenshaw explains. "We observed that plasma delayed the time for pigs to get infected whereas, pigs with non-plasma diets got infected faster. Plasma also helped reduce the viral load in pig tissues."


Subsequent research ventured further into a trial entailing the use of an intranasal vaccine and exposing pigs "to ‘trojan' pigs that are intentionally infected with ASF."


"When vaccinated pigs were fed porcine plasma in the diet, they did not get infected when exposed to the infected ‘trojan' pigs," he says. "Some of the vaccinated pigs fed a diet without plasma got infected with ASF in blood and tissues. However, none of the vaccinated pigs died because of ASF."


These disease-resisting benefits of plasma-supplemented diets are something that Dr. Crenshaw wishes to address during his presentation at VIV Asia. The presentation also shines the spotlight on the continuing development of a vaccine against ASF. This vaccine holds promises to offer "very good protection" against the disease, he remarks.


The application of plasma can bolster the vaccine's efficacy. "About nine days post-exposure, plasma-fed pigs had an increased amount of T-cells, which helped signal the body's defense mechanism to prevent infection," Dr. Crenshaw explains.


CD8-positive T-cells, specifically, are produced in higher amounts in the animal's blood due to plasma's stimulation. "These cells recognise the virus and secrete interferon gamma that clears it out of the tissue and prevents it from replicating," Dr. Crenshaw says. "It is thus implied that plasma nutrition aids in priming the immune system to be more efficient in resisting infection, especially during exposure. It also suggests that plasma nutrition can enable the vaccine to work more effectively."


Dr. Crenshaw proposes that "In theory, feeding pigs with plasma may also help improve efficiency of vaccines used to protect pigs from other pathogens as well." Additionally, the use of plasma in feed may support better nutritional strategies, helping to manage overall swine herd health, Dr. Crenshaw reiterates.


He emphasises that plasma appears to boast a "broad spectrum" of effects against various pathogens.


"It is therefore important that plasma is included in the diet to protect the pig against infection," Dr. Crenshaw says



APC team would like to invite everyone to register and attend "Plasma improves ASF vaccine efficacy" session presented by Dr. Joe Crenshaw at 2:00–2:45 pm (Thai time) on March 9, 2023, at Jupiter 11 room, 1st level, IMPACT Challenger Hall 3, VIV Asia 2023.


- Terry Tan, eFeedLink