A dollar saved is a dollar earned or so the common adage goes. With so many uncontrollable costs in the swine industry, everyone is looking for ways to do more with less. The same holds true when it comes time to formulate sow diets.
“Swine nutritionists can often formulate less expensive diets when they use some high fiber co-products,” explains Hans H. Stein, a professor at the University of Illinois. “But the flip side is that sows don’t digest the fiber as well as they do starch from grain, and therefore they typically have a lower energy value from high-fiber ingredients like wheat middlings in the diets.”
Stein and his team recently set out to determine if adding an enzyme could help with the digestion of the fiber, allowing the sow to get more energy out of a high-fiber ingredient.
Two gestation and two lactation diets were formulated to meet estimated requirements for gestating and lactating sows. Within each state of production, a control diet containing corn, soybean meal, corn dried distillers grains with solubles (DDGS), wheat middlings and soybean hulls was formulated. An additional diet was formulated by adding the enzyme xylanase to the control diet. All diets were fed as mash diets during the two reproductive cycles.
One exception was that the lactation diet did not contain the DDGS, he says. They determined the digestibility in gestation and also in lactation and followed the same sows for two reproductive cycles to obtain a good data set.
“The overall results indicated that if we add xylanase, then we could actually increase digestibility of energy, both in gestation and in lactation,” Stein says. “The sows got more energy out of the diets when we used the enzyme, which was exactly what we had hypothesized.”
Do the Numbers Work Out?
As with any additive in a diet, he says it has to pencil out.
“We want to make sure that if you add something to the diet, that you also have a payback,” Stein explains. “In this case, there was a sufficient increase in energy digestibility that we could justify the cost of adding the enzyme.”
The data showed that adding xylanase to diets for gestating and lactating sows had no effects on sow body weight changes, number of pigs per litter, or birth weights of pigs during two consecutive reproductive cycles. Xylanase did not impact the immunoglobulin composition of colostrum and milk during the second cycle. However, in late gestation of the first cycle, xylanase increased the digestibility of dry matter, insoluble dietary fiber and total dietary fiber. In the second cycle, xylanase increased the digestibility of dry matter, gross energy and concentrations of digestible energy. It also increased the digestibility of dry matter, gross energy, insoluble dietary fiber and total dietary fiber, and concentrations of digestible energy in lactation in both cycles.
“This means there is an opportunity to include more fibrous ingredients in diets for lactating sows with the addition of xylanase,” he says.
Reduced Manure Output
Fecal matter was also measured, but Stein says it was not a focus of the study. However, researchers found that feeding xylanase reduced manure output, too.
“That’s where the increased energy came from -- the sow was simply able to convert some of that digestible fiber that otherwise went out in the feces into energy,” he says. “They were able to convert or ferment that and then absorb the energy from the fiber.”
The side benefit is that less manure is produced because there’s less fiber coming into the manure, he points out.
Stein believes the most important takeaway for producers is that they can get more energy out of high-fiber ingredients in diets if they use enzymes. In this case, xylanase helped increase energy digestibility.
“The sows will eat a little bit less feed because they get more energy out of the feed that they do eat,” he says.
This study, “Exogenous xylanase increases total tract digestibility of energy and fiber in diets for gestating and lactating sows, but does not influence reproductive performance of sows,” was first published in Animal Feed Science and Technology.
