Evaluation of dietary trace mineral supplementation in young horses challenged with intra-articular lipopolysaccharide.

The research article investigates the effect of dietary trace mineral (TM) supplementation on young horses subjected to a single inflammatory stimulus. This study is critical as it helps understand how TM can support cartilage metabolism, healing, and growth.

Experimental Methodology

• The study involved sixteen weanling Quarter Horses, each weighing about 255 ± 22 kg. These horses were part of a 56-day trial designed to examine the influence of TM source on intra-articular inflammation following an acute inflammatory insult.
• Horses were divided by age, sex, and body weight (BW) and then randomly assigned to a dietary treatment. The treatments contained Zinc (Zn), Manganese (Mn), Copper (Cu), and Cobalt (Co), either as inorganic sources (CON) or as complexed TMs (CTM).
• The researchers implemented dietary control for all the horses. They were fed a diet of a treatment concentrate and coastal Bermudagrass hay which met or exceeded NRC requirements.
• On the 42nd day, the researchers injected carpal joints with lipopolysaccharide (LPS) or sterile lactated Ringer’s solution (LRS; contralateral control). Synovial fluid was collected at different time points following the injection and analyzed for TM concentration, prostaglandin E (PGE), carboxypeptide of type II collagen (CPII), collagenase cleavage neopeptide (C2C), and aggrecan chondroitin sulfate 846 epitope (CS846).

Findings of the Study

• The study found that trace minerals peaked at the 6th hour after the LPS injection and reduced to preinjection values by the 168th hour in both the CON and CTM-LPS knee groups. In the CTM-Lactated Ringer’s Solution group, the peak in minerals was delayed until the 12th hour.
• A more significant increase in synovial fluid Cu and Se concentrations were observed in the LPS-injected knees, and Co was highest in the CTM-LPS group.
• For Zn, the peak concentration occurred at the 6th hour in CON, while it was delayed till the 12th hour in CTM.
• When observing Mn, the peak synovial concentration occurred at the 6th hour in LPS knees compared to the 24th hour in LRS.
• Higher Synovial PGE, C2C, CPII, and CS846 concentrations were observed with LPS, and C2C was higher in CTM compared with CON. The CPII and PGE concentrations, however, were unaffected by diet.
• Finally, a significant interaction was detected for CS846. In the CTM group, concentrations of CS846 peaked at 12 hours, whereas in the CON group, the peak was at 24 hours but at a lower concentration.

Conclusion

Based on the observations, the researchers concluded that an adequate intake of a complexed trace mineral source could support cartilage metabolism — particularly increases in aggrecan synthesis and type II collagen breakdown — after an intra-articular LPS challenge in growing horses. This finding holds significant implications for horse healthcare and diet planning, especially in managing inflammation and maintaining cartilage health.