Effect of replacing corn with hulled and hulless or low-amylose hulless barley varieties on growth performance and carcass quality of italian growing-finishing pig

ABSTRACT: A study was conducted to evaluate the\r\neffect of diets based on hulled or hulless (normal- and\r\nlow-amylose) barley varieties on growth performance\r\nand carcass characteristics in heavy growing-finishing\r\npigs for the production of protected designation\r\nof origin (PDO) Italian products. The study was performed\r\nwith 40 gilts and 40 barrows (Italian Duroc ×\r\nItalian Large White). Four diets were formulated: 1)\r\ncorn-based diet (control), 2) control diet with 80% of a\r\nnormal-amylose hulled barley variety named Cometa\r\n(Cometa), 3) control diet with 80% of a normal-amylose\r\nhulless barley variety named Astartis (Astartis),\r\nand 4) control diet with 80% of a low-amylose hulless\r\nbarley variety named Alamo (Alamo). The diets\r\nwere formulated according to 3 growth phases (P1,\r\n40 to 80 kg BW; P2, 80 to 120 kg BW; and P3, 120 to\r\n170 kg BW), with the same Lys:DE ratio (2.60, 2.20,\r\nand 1.80, respectively in P1, P2, and P3) according\r\nto the NRC requirements for P1 and P2 and according\r\nto requirements for high-performing pigs for P3.\r\nThe diets were analyzed for their in vitro starch digestion\r\npotentials (predicted glycemic index, pGI) and\r\nfor their resistant starch (RS) contents. In P1, P2, and\r\nP3, the Alamo diet had the numerically lowest RS\r\ncontents and greatest pGI values, whereas the control\r\ndiet had the numerically greatest RS contents and\r\nthe lowest pGI values. Throughout the study, the pigs\r\nfed Cometa and Alamo diets grew faster (P < 0.01)\r\nthan those fed the control diet, whereas pigs receiving\r\nAstartis diet grew in a similar manner to those receiving\r\nall the other diets. Pigs fed Cometa and Alamo\r\nachieved greater final BW (P < 0.01) compared with\r\nthose fed the control diet. The pigs receiving the\r\nAstartis diet had a mean final BW similar to that of\r\nthe pigs fed other diets. Throughout the study, the\r\ncontrol group had a lower grams per megacalorie DE\r\n(P < 0.01) compared with the pigs fed diets with barley,\r\nwhereas the gain per megacalorie of DE (G/Mcal\r\nDE) was greater (P < 0.01) for the pigs fed hulled\r\nbarley compared with the pig fed hulless barleys.\r\nNo difference in carcass characteristics was found\r\namong treatments (P > 0.05). This study showed that\r\ndiets based both on hulled and hulless barley might\r\nbe suitable for the heavy pig breeding intended to\r\nthe production of Italian PDO products. In addition,\r\nhulled or low-amylose hulless barley could be valuable\r\nto support maximum pig growth performance\r\nwithout affecting carcass composition.