A number of minerals and feed ingredients used alone or in combination may help minimize osteochondrosis.
A team of Kansas State University (KSU) researchers has concluded that very preliminary evidence suggests that feeding certain mineral supplements or feed ingredients may reduce the incidence of lameness in sows.
Lameness or osteochondrosis affects an estimated 85-90% of all pigs. Osteochondrosis, one of the two primary causes of sow removal, is the failure of cartilage to fully develop into bone, leaving an area of cartilage exposed.
The condition is very painful because of the high number of nerve endings that are essential to maintain balance and movement, says Jim Nelssen, KSU Extension swine specialist and one of the study group's authors.
But he cautions that this report provides very preliminary data, and more research will be needed before definitive recommendations can be made.
For more details of this research, included in the 2006 KSU Swine Day Report of Progress, go to www.asi.ksu.edu/swine  and scroll down to Swine Day Reports.
The two main changes in cartilage that have been identified with osteochondrosis are a loss of two important types of proteins within cartilage: proteoglycans and collagen type II. When these two proteins are deficient, the ability of the cartilage to repair itself is impaired.
This deficiency causes structural change of the main cartilage, resulting in the formation of abnormalities that reduce the ability of the joint surface to support the weight of the animal (see picture).
Several trials found no link between growth rate and osteochondrosis.
KSU conducted an experiment to screen dietary ingredients in cartilage and bone metabolism for their role in number and severity of lesions due to osteochondrosis in grow-finish pigs.
Eighty PIC gilts weighing 86 lb. were placed on test in an 84-day study, and assigned to one of eight treatments:
Feeding a standard corn-soy “control” diet with 3.5% choice white grease (CWG).
Replacing CWG with 3.5% fish oil, shown to provide a source of fatty acids that play an important role in the development of the immune system. Fish oil decreases gene expression of compounds involved with inflammatory responses.
Providing proline and glycine, which serve as non-essential amino acids that comprise the basic parts of collagen, the fibrous protein contained in connective tissue and bones.
Supplementing leucine, isoleucine and valine amino acids, which are highly concentrated proteins found in cartilage. These elements may be involved in preventing excessive protein loss due to periods of stress.
Adding silicon at 1,000 ppm., a substance shown to stimulate collagen formation to increase bone mineral density.
Providing 250 ppm. and 100 ppm. of copper and manganese, respectively, levels proven to stabilize and support bone structure.
Supplementing diets with methionine and threonine, which have been shown to aid in collagen production.
Combining ingredients tested in diets 2 through 7.
At the end of the trial, pigs were weighed and transported to the KSU Meats Laboratory where the left hind legs of the gilts were analyzed for lesions due to osteochondrosis.
The left femur was screened for cartilage irregularities and joints were checked for cartilage abnormalities and lesions.
Bone, Joint Evaluations
As depicted in Table 1, pigs fed diets containing fish oil or silicon tended to have a higher severity score for external abnormalities, compared with pigs in the other dietary treatments.
Pigs fed high levels of methionine/threonine, copper manganese or silicon tended to have lower cartilage lesion severity scores, compared with controls or other dietary groups.
Moreover, pigs fed high levels of methionine/threonine or the combination diets containing all ingredients tended to have lower total severity scores than those pigs fed the control diet or fish oil, says Nelssen.
Plus, pigs fed additional copper manganese, methonine/threonine or the diet containing all ingredients recorded lower overall severity scores, compared with scores of pigs fed the control or fish oil diet.
Pigs fed diets with added amino acids had lower external and total severity scores than other groups, but pigs fed diets containing minerals (silicon or copper and manganese) tended to have lower cartilage severity scores and lower overall severity scores.
High levels of methionine/threonine tended to reduce the total severity score, while those feed ingredients plus silicon or copper and manganese may reduce the severity of lesions due to osteochondrosis.
Methionine/threonine is thought to have indirect effects on cartilage metabolism. Methionine may contribute to cartilage growth, while threonine can be converted to glycine, which relates to production of collagen.
“Feeding ingredients such as methionine/threonine, copper and manganese, silicon or a combination of these ingredients that are involved in cartilage and bone metabolism, may help reduce the incidence of osteochondrosis by either positively influencing cartilage/bone metabolism, or by preventing excess cartilage degradation,” says Nelssen.
Other KSU scientists contributing to this research work were: N.Z. Frantz; G.A. Andrews, DVM; M.D. Tokach; J.M. DeRouchey; S.S. Dritz, DVM; and R.D. Goodband.
|Animals with lesions||9||9||9||9||6||7||7||7|
|aEach value is the mean of 9 or 10 replications, with one pig per pen, initially 86 lb. and final wt. 290 lb.|
|bTotal faces showing lesions at the articular cartilage and growth plate, evaluating 12 cut surfaces.|
|cSum of external abnormalities, articular faces and growth-plate faces.|
|dSum of severity scores for external, articular-cartilage and growth-plate faces.|
|eCalculated as the number of abnormalities multiplied by the severity for each location, and then summed.|
|fghTreatments with different superscripts differ (P<0.05).|
|iBCAA are “branched chain amino acids” representing leucine, isoleucine and valine.|