In a recent 43-day trial involving 912 pigs, the team of scientists tested varying levels of feed grade amino acids with L-lysine added to the diets of late nursery and growing pigs.
“We found that if we increase the percentage of L-Lysine as a proportion of total digestible lysine, daily gain and feed efficiency improves,” said K-State graduate student Hadley Williams, who led the study.
But the researchers also found that when the proportion of total digestible lysine exceeds 24% of the diet, feed efficiency worsened.
In the trial, researchers found that decreasing the amount of soybean meal below 30% and increasing the amount of L-lysine could positively impact growth performance, assuming all other amino acid (AA) ratios are adequate.
The findings build upon other research conducted at K-State showing the importance of using optimum levels of feed grade AAs, said K-State Research and Extension livestock specialist, Joel DeRouchey.
By knowing the ideal levels of L-lysine to add to the diets of growing pigs, nutritionists will be able to formulate diets that improve pig performance and producers’ profitability, said Williams.
“Maintaining these ratios of amino acids in the diet may allow higher levels of amino acids to replace soybean meal without reducing pig performance,” said the researcher.
Other AAs of interest included valine and isoleucine, he added.
“The use of feed grade amino acids also is essential for reducing nitrogen excretion in manure and reducing dietary soybean levels to promote gut health, especially in young pigs.”
Williams presented the findings during K-State’s annual Swine Day.