Three years ago, Bert VanBoekel, a 250-sow, farrow-to-finish operator near Woodstock, Ontario was struggling to control postweaning diarrhea in newly weaned pigs.
Mortalities in the nursery ran around 5%. The K88 strain of E. coli was identified as the culprit causing the malady.
While scanning a magazine article one day, some research being conducted at the University of Manitoba caught VanBoekel's eye. He contacted the university and became one of the first to try a new feed additive containing powdered egg yolk carrying antibodies to the K88 strain of E. coli. K88 is a leading cause of postweaning diarrhea in pigs.
It worked. “It was really good,” comments VanBoekel. “I was having up to 5% mortality and it went down to 2% as soon as I put it in the feed. I won't say it's 100%, but it's better than anything else I've tried.”
Greg Simpson, swine marketing coordinator with Agribrands Purina Canada, consults with VanBoekel and many other customers across Ontario, Quebec and the Maritime provinces.
“The egg yolk is nice,” says Simpson. “It's targeted specifically against certain strains of E coli; most other additives are broad spectrum and only deal with symptoms.”
Agribrands has offered an egg yolk powder additive for more than three years, and it's proven itself, he says. The egg yolk carries antibodies to the two most common strains of E. coli for postweaning pigs, K88 and K99.
“We have a lot of anecdotal evidence, and some trial work we've done with producers,” says Simpson. “It's very effective. If you know a farm has an E. coli challenge because it's been serotyped, you can target that egg protein to that problem. It's quite amazing.”
This optional approach comes at a time when two popular methods of fighting postweaning diarrhea — antibiotics and porcine plasma — are being closely scrutinized.
Unlike an antibiotic that directly attacks and kills microorganisms, an antibody binds to a specific microorganism (such as K88) and neutralizes it. A K88 antibody prevents this specific strain of bacteria from attaching to the lining of the pig's intestine, leaving the bacteria to pass harmlessly through the digestive system.
Stress of Weaning
Weaning is a stressful time and the 2-week-old piglet is particularly vulnerable. After being separated from the sow and its primary source of nutrients, milk, it is mixed with pigs from other litters and placed on a diet of solid food and water.
“We feed the egg yolk powder in the nursery diet for about three weeks. The first two weeks postweaning is the critical time where it has the most effect. It gets them over that stress period,” Simpson says.
A few weeks after the transition, pigs combat scours-producing bacteria with an increase in the acidic level in the intestine.
The product is relatively expensive, as an additive, but if you compare it to the cost of antibiotics, the costs are similar.
About half the customers who try egg yolk powder keep it as a permanent part of the nursery ration, says Simpson. Most others will keep it four to six months, then try to reduce or eliminate the product.
The University of Manitoba operates one of four swine research centers in western Canada. Their research with E. coli antibodies in powdered egg yolk dates back to late 1998. However, the concept was first suggested in 1947 and research has been done at various places since then. Some products have been brought to market.
Augustine Owusu-Asiedu earned his PhD at the University of Manitoba with the egg yolk studies.
Postweaning diarrhea problems caused by E. coli have worsened as microbes develop antibiotic resistance. The public outcry about antibiotic residues in meat and meat products and the call for a ban on antibiotics as growth promoters has created incentives to identify non-antibiotic means to control or prevent postweaning diarrhea, says the researcher.
Spray-dried porcine plasma, as a feed additive, has proven an effective alternative in controlling postweaning diarrhea and in improving young pigs' performance. However, due to the controversy over Mad Cow Disease, the European Union now bans the use of animal protein and animal by-products as a feed ingredient, he explains.
Owusu-Asiedu conducted a series of E. coli control studies comparing egg yolk antibody obtained from laying hens immunized with K88 antigen to plasma protein and antibiotics, using a pea protein isolate as a baseline diet.
The difference between pea protein and plasma protein is the presence of specific anti-K88 antibody in spray-dried plasma protein. Based on this hypothesis, pea protein was supplemented with egg yolk containing specific anti-K88 antibody.
The pea protein without egg yolk antibody failed to protect piglets when challenged by K88 bacteria. Up to 40% of the piglets developed severe diarrhea and died. However, piglets given pea protein supplemented with egg yolk antibodies or plasma protein produced similar recovery rates when challenged with equal doses of K88 bacteria.
Owusu-Asiedu used a level of 0.5% egg yolk in the diet. “That was a lot more than necessary,” he says. “The commercial product recommends 0.1 or 0.2%.”
Egg yolk antibody can contain specific antibodies for K88, F18 and K99. It is therefore important to confirm the specific E. coli strain responsible for the postweaning diarrhea, he says.
If there's time, the best way to control an outbreak is to isolate the specific E. coli strain and use that to inoculate hens; in turn, they'll produce the antibodies needed for that hog farm.
Some questions and some differing opinions still remain among researchers. For example, Owusu-Asiedu would like to study the maximum level of egg yolk antibody required to neutralize E. coli infection, whether antibodies could clean the sow just before farrowing, the effect of heat treatment on antibody stability and activity of antibodies in the gut. Research in a variety of barn conditions is also very important, he says.
The Ontario Veterinary College (OVC) at Guelph, Ontario is also advising caution. OVC field and lab trials with egg yolk antibodies have not achieved clear-cut, positive results, says Bob Friendship, DVM and OVC professor in population medicine.
In the lab, the egg yolk antibody was fed at the recommended level and 10 times the recommended level. Controlled levels of E. coli were used to challenge the pigs. No response was seen in this controlled situation, either.
“We were very high on it (egg yolk antibodies), and the work done in Manitoba is good work,” says Friendship. “I expected we would have one group with a lot of scours and another with far less or none.” Although no response was seen, Friendship feels further testing is needed.
He adds, “Postweaning diarrhea in piglets is a complex issue. There's a mixture of confounding factors, not just the presence of the organisms, so it could be that adding egg yolk antibody just tips the balance enough on some farms to give the pig the advantage.”
John Hare, president of Nutratech Inc., acknowledges that this product isn't the first of its kind. Competition originated several years ago with minimal results due to inadequate levels of product strength, he explains. He believes that the Nutratech product, based on research conducted at the University of Manitoba and elsewhere, is overcoming some negative opinions associated with these earlier products.
Nutratech Inc. of Winnipeg, Manitoba produces egg yolk powder as a feed additive. It is available commercially in Canada through J.H. Hare & Associates Ltd. and internationally through regional distributors. In the U.S., Tech Mix of Stewart, MN, is using Nutratech's egg yolk antibodies in several of their newly formulated products. Contact Tech Mix at 877-466-6455. Nutratech's John Hare can be contacted via [email protected] .