254 Mineral Source Matters for Cartilage Development to Support Structural Integrity

Abstract

Abstract Lameness is a welfare issue generally associated with increased growth rate. Objectives of this study were to 1) compare efficacy of inorganic (ITM) and organic trace mineral (OTM) sources on lameness incidence and effects on bone and cartilage biomarkers, and 2) determine if the biologically relevant biomarkers were detectable in saliva. Dietary treatments were fed for 70 d and included: 1) ITM sulfates, Zn-Cu-Mn supplemented at 120-20-40 mg/kg diet, and three OTMs supplemented at 80-10-20 Zn-Cu-Mn mg/kg diet, respectfully. The OTM treatments included a non-specific amino acid complex (Trt 2 – OTM complex), a glycinate (Trt 3 - OTM glycinate), and a metal methionine hydroxy analogue chelate (Trt 4 – OTM MMHAC) supplied as MINTREX trace minerals (Novus International, Inc., St Charles, MO). The study consisted of 144 barrows (56 kg initial BW; 36 pigs/trt; 18 pigs/pen on slatted concrete floors). A source of ractopamine hydrochloride (10 mg/kg) was fed the last 28 d of the trial to induce increased growth rate. Measurements included gait scoring (0-4; GS ≥ 2 defined as lame) and serum and saliva bone synthesis (osteocalcin), bone degradation (CTX1) and cartilage synthesis (P2CP), and cartilage degradative biomarkers (CTX2, C2C) and synthesis:degradation ratios measured at baseline, d 7, d 36 and d 70. Individual biomarkers were logarithmically transformed (base 10). Proc Mixed GLM procedure of SAS was performed on log-transformed data and means were determined using LSD test. Nonparametric comparisons (% lameness) were tested using Chi-squared analysis. A P-value < 0.05 was considered significant and P ≤ 0.10, a trend. As shown in Table, 1, lameness incidence was greatest for pigs fed ITM and OTM glycinate which was greater than OTM complex and MMHAC (P = 0.10). In general, there was good agreement between serum and saliva biomarkers, with pigs fed MMHAC having the greatest serum bone synthesis biomarker (osteocalcin) which differed from pigs fed OTM complex (P < 0.05). Cartilage synthesis concentrations (P2CP (serum and saliva); and P2CP/C2C and P2CP/CTX2 ratios (saliva) were also greatest for pigs fed MMHAC trace minerals (P < 0.05). Neither bone nor cartilage biomarkers were different between pigs fed ITM and OTM complex or glycinate. Osteocalcin was 10-fold less in saliva compared with serum. No treatment differences were observed in saliva for bone synthesis. The results demonstrated trace mineral source matters with respect to structural health. Significant differences between OTM sources were observed with MMHAC resulting in the highest bone and cartilage synthesis biomarker concentrations in serum and highest biomarkers for cartilage synthesis and synthesis:degradation ratios in saliva. Saliva appears to be a sensitive medium for measuring joint health biomarkers.