title: Effects of increasing co-product inclusion and reducing dietary protein on growth performance, carcass characteristics, and jowl fatty acid profile of growing-finishing pigs.
abstract: Dietary inclusion of co-products (Co-P) provides opportunities for diversifying the feedstuff matrix by using local feedstuffs, reducing feed costs, and producing value-added pork. In 2 studies, we determined effects of Co-P (canola meal, distillers dried grains with solubles, and co-extruded oil seed and field pea) inclusion level and reduced dietary CP concentration on growth performance, carcass characteristics, and jowl fatty acid profiles of growing-finishing pigs. Pigs were fed isoenergetic and isolysinic diets over 4 growth phases with 8 pen observations per dietary regimen. At slaughter, carcasses were characterized for all pigs and jowl fat was collected from 2 pigs per pen. In Exp. 1, 1,056 pigs (initial BW, 35.3 ± 0.4 kg) were fed 3 levels of dietary Co-P (low, mid, and high) and 2 CP concentrations (low and normal). Overall (d 0 to 86), increasing Co-P inclusion from low to mid or high decreased (P < 0.001) ADFI and ADG of pigs. Low CP concentration increased (P < 0.05) ADFI and ADG compared with normal CP concentration. An interaction (P = 0.026) occurred between dietary Co-P inclusion and CP concentration for G:F; low CP reduced (P < 0.05) G:F compared with normal CP for pig fed low Co-P, but G:F did not differ between CP concentrations for pigs fed mid and high Co-P. Increasing dietary Co-P inclusion from low to high increased (P < 0.001) α-linolenic acid (ALA) in jowl fat but decreased (P < 0.001) carcass weight and loin depth. In Exp. 2, 1,008 pigs (initial BW, 30.3 ± 0.4 kg) were assigned to 5 dietary regimens with Co-P increasing from 2.0 to 50.0% or a sixth regimen with 10% extra supplemental AA for the 37.5% Co-P diet. Overall (d 0 to 97), increasing Co-P inclusion did not affect ADFI, ADG, and G:F. Increasing dietary Co-P inclusion linearly decreased (P < 0.01) carcass weight, dressing percentage, backfat thickness, and loin depth but linearly increased (P < 0.001) jowl ALA. Supplementing 10% extra AA to the 37.5% Co-P diet did not affect growth performance or dressing percentage but increased (P = 0.014) carcass leanness and decreased (P = 0.023) backfat thickness compared with the 37.5% Co-P diet, indicating that dietary AA supply did not limit BW gain. In conclusion, Co-P can be included by up to 50% in diets for growing-finishing pigs without affecting G:F. However, increasing dietary Co-P may reduce ADG, ADFI, and carcass weight even if diets are balanced for dietary NE and standardized ileal digestible AA content.
authors: Department of Agricultural, Food and Nutritional Science, University of Alberta, Edmonton, AB T6G 2P5, Canada.
authors: R
authors: R
authors: Jha
authors: J K
authors: JK
authors: Htoo
authors: M G
authors: MG
authors: Young
authors: E
authors: E
authors: Beltranena
authors: R T
authors: RT
authors: Zijlstra
mesh_terms: D000596:Amino Acids / Q000008:administration & dosage / Q000378:metabolism; D000821:Animal Feed / Q000032:analysis*; D000818:Animals; D001823:Body Composition; D001835:Body Weight; D004032:Diet / Q000662:veterinary*; D004044:Dietary Proteins / Q000378:metabolism; D019587:Dietary Supplements / Q000032:analysis; D004305:Dose-Response Relationship, Drug; D005227:Fatty Acids / Q000378:metabolism; D015525:Fatty Acids, Omega-3 / Q000378:metabolism; D005260:Female; D019597:Flax / Q000378:metabolism; D008297:Male; D008460:Meat / Q000032:analysis*; D009928:Organ Specificity; D011897:Random Allocation; D012639:Seeds / Q000378:metabolism; D034421:Sus scrofa / Q000235:genetics / Q000502:physiology*
chemical_list: D000596:Amino Acids; D004044:Dietary Proteins; D005227:Fatty Acids; D015525:Fatty Acids, Omega-3