By Argenis Rodas-Gonzalez

Editor’s note: Argenis Rodas-Gonzalez is an associate professor in the Department of Animal Science at the University of Manitoba. He can be contacted at argenis.rodasgonzalez@umanitoba.ca.

Profitable, cost-effective swine production requires healthy animals, higher performance, increased feed efficiency and making the best use of available nutrients.

Feed efficiency can be described as the biological basis of how pigs consume and metabolize feed to grow and produce an edible product. This is a complex trait based on a pig’s ability to store and use nutrients from feed, such as fats, carbohydrates, and proteins. Skeletal muscle plays a significant role in using and storing those nutrients. Most of the efforts to improve feed efficiency have been focused on formulating balanced diets through investigating nutrient composition and genetic selection for carcass leanness.

Feed efficiency can be expressed as a feed conversion ratio (FCR), which is defined as feed intake over body weight gain. A low-FCR value means animals consume less feed per unit of gained body weight, making them highly efficient; in contrast, a high-FCR value means animals consume more feed per unit of gained body weight, making them less efficient. There are other expressions of feed efficiency, such as residual feed intake and lean feed conversion, but these will depend on additional knowledge required for informed decision-making.

Feed efficiency factors vary

A common approach to improve feed efficiency is to supply appropriate nutrient requirements for animals; however, the improvement could be limited and depends on the ingredient composition of the feed, which can vary in nutrient digestibility.

On the other hand, purebred pigs are selected for feed efficiency at the nucleus level, and genetic selection to improve feed uptake continues to be a challenge. At Topigs Norsvin, selecting genetics based on the estimated breeding values for a given feed conversion ratio (EBV-FCR) has proven to be an effective strategy to maximize feed efficiency and improve growth performance and carcass composition. However, it is not clear if nutrient digestibility in pigs could be altered by genetic selection for feed efficiency.

Studies have shown that diverse feed efficiency groups resulted in lines of pigs showing both differences in growth performance and digestibility of nutrients, which happens in the gut.

For example, in Yorkshire breeding lines fed with high-energy diets, the digestibility of dry matter, total energy, absorption of nitrogen and other nutrients like fibre are similar in both high- and low-efficiency groups, based on residual feed intake (RFI) values. But when these groups are fed with low-energy diets, the high-efficiency group has greater digestibility of dry matter, total energy, nitrogen and fibre compared to the low-efficiency group; however, low-energy diets reduce growth performance of both efficiency groups.

In contrast, other studies have reported no differences in digestibility among divergent feed efficiency pigs, despite high-efficiency pigs presenting a faster growth and leaner carcasses. Thus, based on some contradictory results, uncertainty exists with selection for feed efficiency and its effect on growth performance, nutrient digestibility and carcass characteristics, especially within Large White lines.

Overcoming the feed efficiency dilemma

My team at the University of Manitoba includes researchers Ethendhar Rajendiran, Gustavo Mejicanos, Laura Beens and Ankita Saikia from the Department of Animal Science. We are working in collaboration with Topigs Norsvin Canada to respond to certain feed efficiency questions that have stumped breeders.

Our project is funded by Topigs Norsvin Canada, the Canadian Agricultural Partnership and the Ag Action Manitoba Research and Innovation program. The investigation is planning to evaluate 2,000 genotyped boars from two Large White dam and sire lines separated into low- and high-feed-efficiency groups based on EBV-FCR values within the breeding line.

This study investigates the variation in growth performance, apparent total tract nutrient digestibility (ATTD) and in-vivo carcass traits in finisher boars selected for low or high feed efficiency. Digestibility is determined by testing manure nutrient levels using an indigestible marker, while in-vivo carcass traits refer to the lean yield of the whole pig, determined using Computer Tomography (CT) scanning. Boars are selected at 23 weeks of age based on their feed efficiency value and fed a mixed corn-soybean meal-based diet using feeding stations that record individual feed intake and body weights.

Preliminary findings indicate that the sire line was heavier, with a final weight of more than 9.69 kilograms, growing more rapidly and more efficiently than the dam line, gaining more than 130.69 grams per day with a feed conversion ratio of less than 190 grams of feed consumed to gain one kilogram of body weight.

In addition, sire line presented greater loin depth, at more than 6.92 millimetres, and thinner fat depth, at less than 2.60 millimetres. However, there was no significant difference in nutrient digestibility between lines. On the other hand, regardless of the genetic line, and compared to the low-efficiency pigs, the high-efficiency pigs consumed less feed, at less than 284.97 grams per day, were more efficient, with a feed conversion ratio of less than 260 grams of feed consumed to gain one kilogram of carcass weight, had thinner fat depth at less than 3.05 millimetres, along with greater loin depth more than 6.92 millimetres compared to low-efficiency pigs.

The high-efficiency pigs were better able to digest crude protein and tended to show higher phosphorus and calcium digestibility compared to low-efficiency pigs. Based on the estimated protein deposition and the average feed intake one week before sampling, the amount of digestible lysine content met the requirements for the average pig. Nevertheless, high-efficiency pigs had a reduced feed intake, implying that they might have experienced a shortage of lysine in the diet. Thus, high-efficiency pigs offer favourable growth performance, heavier and leaner carcasses. However, it is still unclear whether the improved digestibility of crude protein was due to a lysine shortage or differences in genetic merit for feed efficiency.

Forward thinking for progressing efficiency

The University of Manitoba and Topigs Norsvin are also exploring the pig gut microbiome to identify the favorable microorganisms that contribute to feed digestibility, along with determining feed digestibility by using near infrared spectroscopy, and in-vivo leanness by CT scan. The findings may allow us to better understand the relationship between the gut microbiome, nutrient digestibility and genetics, leading to the improved and more effective selection of pigs for breeding programs.

By Lexie Reed

Editor’s note: Lexie Reed holds a Doctor of Veterinary Medicine from Ontario Veterinary College. She can be contacted at lexiereedvm@gmail.com.

Pork-associated human illnesses have drawn unfavourable media attention to the swine industry over the years. In 2018, a pork recall was issued by the Canadian Food Inspection Agency (CFIA) in response to an outbreak linked to an Alberta restaurant. The pathogen responsible for the death of one individual and more than 40 cases of illness was Escherichia coli (E. coli) O157:H7.

As few serious E. coli illnesses have been associated with pork products, there was skepticism that contamination from cattle in the abattoir was truly to blame for the outbreak. However, a 2020 study found that O157:H7 bacteria reside within the intestinal tract of pigs, and though risk of E. coli illness from pork products is low, it can have serious consequences.

Fecal contamination of hog carcasses is a serious risk factor for foodborne illness from pork. For these reasons, cooking pork thoroughly is recommended to kill any bacteria that may be present on the meat. Hygienic removal of the intestines post-slaughter, to prevent the spillage of intestinal contents onto the saleable carcass, is another important step.

But what if there was another layer to the pork safety net?

The need for E. coli antibodies

A 2017 study of provincially licensed abattoirs in Alberta found that 1.8 per cent of carcasses sampled were contaminated with O157:H7, several of which were subtypes of O157:H7 that are of importance to human health. Samples were taken from abattoirs that slaughtered both pigs and cattle and from abattoirs that slaughtered pigs only. No difference in the prevalence of O157:H7 carcass contamination was observed between abattoirs that slaughtered just pigs or pigs and cattle, indicating that O157:H7 contamination of hog carcasses is a result of the pathogen occurring within the pigs themselves.

O157:H7 antibody technology was originally proposed for development in cattle, as O157:H7 contamination is predominantly associated with ruminants. However, the efficacy and safety studies in mice are more applicable to monogastric species, and thus the development in pigs was pursued. Success in monogastric studies may still lead to the development of direct-fed O157:H7 antibodies to cattle.

Developing an E. coli antibody to feed pigs

Agriculture and Agri-Food Canada (AAFC) research scientists have recently isolated an E. coli antibody that could neutralize O157:H7. The antibody is synthesized within the plant Nicotiana benthamiana and could be delivered as an edible feed material. Once ingested, the antibodies would bind and neutralize O157:H7 present in the gastrointestinal tract.

Rima Menassa is a genomics and biotechnology research scientist at AAFC’s London Research and Development Centre. She conducted the study that found the antibodies to be effective at neutralizing O157:H7 in cell cultures. Presently, Patti Kiser of Western University is conducting a study to determine if the direct-fed antibody can neutralize O157:H7 in mice, which would bring the technology one step closer to proof of concept in livestock.

“If feeding the antibody to mice who already have O157:H7 established in their intestines prevents shedding of the pathogen, then antibody feeding short-term prior to slaughter could be an option in pigs,” said Menassa. “If, however, the antibodies only prevent O157:H7 from colonizing the intestinal tract when it is introduced to naïve mice, then it is more likely that the antibodies would need to be fed from an early age, before significant O157:H7 exposure.”

If successful, the outcome of the study could lead to commercialization of the technology. Preventing E. coli from colonizing the gastrointestinal tract or reducing shedding of the pathogen would reduce the risk of O157:H7 contaminating the carcass at time of processing. Further, this technology could reduce the risk of contaminated manure, which may be spread on crop fields as fertilizer.

The plant used to produce the antibody, Nicotiana benthamiana, is a plant related to tobacco, native to Australia. It is commonly used for molecular biology studies and has been used to produce vaccines and other pharmaceutical products, thanks to its natural ability to express foreign gene sequences.

Although the dose regime has not yet been established, it is unlikely that the amount fed of the plant material would contribute any appreciable nutritional or fibre content. The current study in mice will explore both efficacy and safety of the plant-encapsulated antibodies. The results of this study will also help to establish a timeline for feeding pigs pre-slaughter. This study is a collaboration between AAFC and PlantForm Corp., a start-up plant biotechnology company based in Guelph, Ontario.

Direct-fed antibodies have a future

Though still in its infancy, direct-fed antibody technology is on the horizon. The commercialization of this technology for O157:H7 could expand to other significant zoonotic pathogenic bacteria in pigs, providing abattoirs with another mechanism to reduce foodborne illness from pork that starts before the pigs even reach the packing plant.

Even beyond a food safety application, this pharmaceutical delivery system could create a new avenue for vaccine and antibody delivery through feed, particularly at a time when barn labour is a significant challenge for many producers.

Whether or not an E. coli O157:H7 antibody for pigs is embraced as a method for preventing foodborne illness from pork, the development of a novel delivery method for antibodies could be a breakthrough product for the swine industry.

By Ontario Pork

With COVID-19 restrictions easing, producers and industry partners have been eager to see each other face-to-face, attending meetings the same way we did prior to the pandemic.

While in-person events are mostly preferred to virtual ones, the new virtual reality that has emerged since COVID-19 is also showing some benefits when it comes to creating connections between producers and between producers and consumers.

In Ontario, two prominent producers have shown great initiative in leveraging the advantages that digital spaces can provide – from sharing information with each other, to sharing information with classrooms and the general public.

Producers can now meet, no matter where

In February 2021, Dave DeVries, who farms near Mapleton, just south of London, started planning a virtual meeting place for pork producers – dubbed ‘Swine Online’ – motivated by a TED Talk at the Ontario Agricultural Conference. Collaboration was key to its success, starting with the witty name.

“My wife, Lauren, gets full credit for that,” said DeVries.

Fellow producers Brett Israel and Daniel Roelands, who farm nearby, worked with DeVries on the details. Tim Blackwell, Ontario’s Chief Provincial Veterinarian, enthusiastically embraced the plan.

“We got a positive response right from the start,” said DeVries. “People definitely wanted it to continue.”

Laura Eastwood, a swine specialist with Ontario Agriculture, Food and Rural Affairs, gave them access to a secure Zoom platform with a chat option.

“Laura is our technical guru,” said DeVries. “She runs the sessions and helps with any connectivity issues.”

Blackwell acts as moderator, and Jaydee Smith maintains the online blog. Recordings are put on a password-protected website for subscribers to view at any time.

“The communication staff at Ontario Pork have also been very helpful in promoting the meetings,” said DeVries. “We have a great group of producers joining us now, some from as far away as Iowa and Saskatchewan.”

Polling questions are sent in advance to find producers who can speak to specific topics, ranging from loading area logistics, to feed costs, to the industry’s carbon footprint and environmental sustainability. Producers can showcase their operations through slides or videos, and products may be discussed, but DeVries cautioned that this is a neutral platform with no place for advertising or sales pitches. He also pointed out the advantages of online meetings.

“For one thing, you don’t have to buy doughnuts,” said DeVries. “Many producers say that they really appreciate being able to see operations all over the province, and there are no biosecurity issues in virtual visits.”

Community connections create interest

Most pork producers are proud to show off their barns and operations, and John Van Engelen of Hog-Tied Farms Ltd., east of Sarnia, is no exception.

Van Engelen’s modern, fully wi-fi-enabled pig barn is ideal for virtual tours. He has been doing online tours for a few years, both for school groups and for other farmers.

“Last year, I was asked to do a farm tour for the Western Fair, and I guess it went well,” said Van Engelen. “Because then the Royal Winter Fair asked me to do theirs, too.”

Van Engelen’s virtual tours have become a popular way for anyone who has never seen a modern pig farm up close to understand how pork production really works. Technology is integral to the operation. His sows are fitted with radio-frequency identification (RFID) tags, which his electronic sow feeders read to ensure each pig receives its specific ration and precise amount, according to size and gestation state.

His hogs are sorted and fed different rations depending on their individual weights. He also uses RFID tags on his hogs in Pig Performance Testers to track growth and gains, to get an average meat per tonne of feed throughout the year.

Van Engelen’s farm was one of the first in Ontario to install an electricity-generating wind turbine, and he even designed a shower for the pigs to enjoy. Presenting urban students his clean, modern barn helps them feel engaged with local farmers.

“When people get to see for themselves how calm, healthy and well-treated the pigs are, it makes a much better connection,” said Van Engelen.

When he gives tours to younger schoolchildren, they mostly want to see cute piglets, but older students are much more informed and aware of the contemporary social issues with farming. They come armed with tough questions about environmental sustainability and animal welfare. Van Engelen welcomes this as an opportunity.

“Most people don’t know much about their food sources, and there are a lot of misconceptions,” said Van Engelen. “The tours are a great way to educate and inform them.”

Van Engelen estimates that, in his time on the farm, his environmental footprint has dropped by half or more. He uses his barn’s own manure as fertilizer and minimizes energy costs with heat exchangers.

“I can raise a larger pig in 50 days less than it used to take to bring one to market 40 years ago,” said Van Engelen.

The most important part of the tours, for him, is that they help make real connections between the community and the food producers they depend on.

“It’s important to correct misunderstandings about farming. This isn’t Old McDonald’s farm anymore,” said Van Engelen.

Embracing, rather than fighting, change

Swine Online and Hog-Tied Farms’ tours are great examples of how producers have demonstrated resilience through the COVID-19 pandemic. Embracing innovation and technology to share experiences will help build long-term connections across the industry.

Even as in-person meetings and events return, it is likely that virtual options, when they make sense, will become permanent in our industry and many others.