Effects of L-carnitine, Selenium-enriched Yeast, Jujube Fruit and Hwangto (Red Clay) Supplementation on Performance and Carcass Measurements of Finishing Pigs

Fifty castrated crossbred ($Landrace{\times}Yorkshire$) pigs, weighing an average of $60.6{\pm}3.1kg$ were allotted to one of five treatments in a randomized block design to examine the effects of dietary inclusion of 0.1% L-carnitine (50 ppm carnitine), 0.1% selenium-enriched yeast (0.3 ppm selenium), 0.1% Jujube fruit or 0.1% Hwangto (Red clay) on pig performance and carcass quality. All diets were based on corn, wheat, soybean meal and wheat bran and were formulated to supply 13.8 MJ DE/kg. Dietary supplementation did not influence daily gain (p = 0.57), feed intake (p = 0.52), or feed conversion (p = 0.32). Digestibility of dry matter (p = 0.60), organic matter (p = 0.74), crude protein (p = 0.76), crude fibre (p = 0.70) and energy (p = 0.75) were also unaffected by inclusion of any of the additives. Tissue samples taken from the longissimus muscle showed that the levels of carnitine (p = 0.0001) and selenium (p = 0.0001) were significantly higher with dietary inclusion of carnitine or selenium-enriched yeast. Dietary treatment did not affect dressing percentage (p = 0.33), carcass lean yield (p = 0.99) or first, $10^{th}$ and last rib midline backfat depth (p = 0.45, 0.82 and 0.47, respectively). Dietary treatment also did not affect the percentages of tenderloin (p = 0.37), bacon (p = 0.36), fat and bone (p = 0.56), picnic shoulder (p = 0.25), skirt (p = 0.80), fresh ham (p = 0.31) or ribs (p = 0.79). However, pigs fed the diet containing Jujube fruit had a higher percentage of Boston butt than pigs fed the carnitine or selenium supplemented diets (p = 0.01). Pigs fed added Hwangto had a higher (p = 0.04) percentage of loin compared with pigs fed supplementary selenium or Jujube fruit. Loin muscle from pigs fed carnitine had a significantly lower Hunter colour value for L (whiteness, p = 0.004) and a higher value for $a^*$ (redness; p = 0.069). The overall results indicate that supplementation with L-carnitine and selenium-enriched yeast can produce pork containing higher levels of carnitine and selenium, which could provide health benefits for consumers of pork without detrimental effects on pig performance.