It was another matter entirely when he decided studying poultry would be his life’s work.
“My dad was not very happy with this,” recalls the NSERC Industrial Research Chair in Poultry Nutrition. “First of all, I went into agriculture when he thought I should go into business or something like that. Then when I went into animals, he couldn’t understand that because he liked plants more. And when I told him I was going into poultry science, he thought I had totally lost my mind.”
He also wondered if his son would have much to do.
“He said chickens were simple animals and wondered how much more there was to know.”
As it turns out, there was an awful lot. And despite a host of major advances during his four-decade-plus career, the list of research questions continues to grow, says Classen.
Poultry is on pace to surpass pork and become the world’s favourite meat by 2020, but there are key challenges, including dealing with higher feed costs and reassuring consumers who are increasingly concerned about animal welfare and food safety.
Classen is a leading figure in nutrition and welfare research, although he is quick to credit his many collaborators and research partners.
“I think one of my strengths is that when a research idea is raised, I recognize where there are issues — and I recognize that I can’t do it all,” he says. “Multi-disciplinary research is not only much better, it’s much more exciting to do.”
And the science is increasingly complex. Take, for example, the simple question of how long to leave on the lights in a chicken barn.
The broiler chicken industry thought it had this one figured out decades ago. Chickens really do eat like birds, feeding a bit at a time and then taking 30- to 60-minute breaks. So, the theory went, keep the lights on longer — 23 hours a day in some barns — and they’ll eat more often and grow faster.
“I’m sure I even taught this in my classes at one time,” says Classen. “But my graduate student, Karen Schwean-Lardner, found the most rapid growth never came from 23 hours of light. Having longer periods of darkness was beneficial.”
This discovery didn’t come from just fiddling with the light timer.
First, there’s a behavioural aspect.
“With the use of video cameras, we discovered sleep-deprived chickens were lethargic and the constant up-and-down feeding disturbed other birds trying to nap. Their comfort behaviours – such as preening or foraging – also decreased in frequency.”
Other studies looked at physiological changes resulting in higher mortality (notably, heart problems), more skeletal problems, and reduced feed efficiency. Researchers are now looking more closely at the metabolic changes that occur during deep sleep (such as a slight drop in body temperature) and how that affects heart and bone development.
Research from Classen’s team has not only prompted shorter ‘days’ in poultry barns; it has had an impact in other areas of poultry welfare and nutrition. Thanks to the $3.6 million in funding from NSERC and industry that came with the research chair, additional studies will build on the latter work by examining the impact of nutrition on bird performance, welfare and health, as well as food safety.
Today’s chickens can reach two or more kilograms during their five- to six-week production cycle, but as with barn lighting, “the more we understand, the more we realize how much there is to know about poultry nutrition,” he says.
“We started from a fairly crude basis,” says Classen. “We knew we needed protein in the diet, and we realized amino acids are the building blocks of proteins. But we needed to know if the amino acids were digestible or not, in order to know whether the bird is getting use from them. We now have a good knowledge of amino acid digestibility, so our future research will focus on where the digestion occurs. Our hypothesis is that characteristic has an important impact on a number of criteria, including growth and performance.”
‘Where’ is far from a simple question. Just as famed astrophysicist Carl Sagan used to rhapsodize about the “billions and billions” of stars in the cosmos, Classen and his collaborators are delving into the equally vast and complex world of an animal’s digestive system.
“Billions and billions says it well,” he says with a laugh. “There are more bacteria than cells in the body of a chicken, and the interactions are so complex. There are some ‘positive’ bacteria and when we see those bacterial populations go up, we seem to see healthier birds. But they’re sitting in an ecosystem with a large number of other bacteria, so when you change the population of one bacteria, it has a phase-shift on other populations.”
It’s research tailor-made for Classen’s multi-disciplinary, collaborative approach.
For example, one of the areas he and his team will be looking at is the digestibility of peas, which are widely grown on the Prairies and could be a lower-cost ration. But they are also more slowly digested, and the research will look beyond just feed efficiency and examine how this changes what is happening in a chicken’s gut and how it affects its metabolism.
“The digestive tract is an amazingly important tissue,” notes Classen. “It doesn’t just digest and absorb, it also has to prevent infection by blocking pathogens."
In this vast but microscopic world, all sorts of things are happening – from the rate of glucose release as starches are digested, to the health effects of “fermentation products.” The macro picture is complex, too, with issues ranging from using nutrition to reduce antibiotic use to feeding the world’s growing population.
“We’re not talking about 10 chickens in someone’s yard, which was what I thought about when I was a kid,” he says. “Chicken production is massively important, and will have a very large impact on feeding the billions of people who will be here by 2050.”
So more than four decades after Classen broke the bad news to his dad, there remains much to do, and the NSERC and industry funding will only be a start.
“We’ve planned some research that will have immediate benefits and can be put in practice in one or two years. But I’m guessing a big chunk of what we’re doing will provide ammunition, so to speak, for another generation of scientists to take further.”