title: Effect of crude glycerol on pellet mill production and nursery pig growth performance.
abstract: The objective of this study was to determine the effects of diets containing crude glycerol on pellet mill production efficiency and nursery pig growth performance. In a pilot study, increasing crude glycerol (0, 3, 6, 9, 12, and 15%) in a corn-soybean meal diet was evaluated for pellet mill production efficiency. All diets were steam conditioned to 65.5 degrees C and pelleted through a pellet mill equipped with a die that had an effective thickness of 31.8 mm and holes 3.96 mm in diameter. Each diet was replicated by manufacturing a new batch of feed 3 times. Increasing crude glycerol increased both the standard (linear and quadratic, P < 0.01) and modified (linear, P < 0.01; quadratic, P </= 0.02) pellet durability indexes up to 9% with no further benefit thereafter. The addition of crude glycerol decreased (linear; P < 0.01) production rate (t/h) and production efficiency (kWh/t). In a 26-d growth assay, 182 pigs (initial BW, 11.0 +/- 1.3 kg; 5 or 6 pigs/pen) were fed 1 of 7 corn-soybean meal-based diets with no added soy oil or crude glycerol (control), the control diet with 3 or 6% added soy oil, 3 or 6% added crude glycerol, and 6 or 12% addition of a 50:50 (wt/wt) soy oil/crude glycerol blend with 5 pens/diet. The addition of crude glycerol lowered (P < 0. 01) delta temperature, amperage, motor load, and production efficiency. The addition of crude glycerol improved (P < 0.01) pellet durability compared with soy oil and the soy oil/crude glycerol blend treatments. Pigs fed increasing crude glycerol had increased (linear, P = 0.03) ADG. Average daily gain tended to increase with increasing soy oil (quadratic; P = 0.07) or the soy oil/crude glycerol blend (linear, P = 0.06). Adding crude glycerol to the diet did not affect G:F compared with the control. Gain:feed tended to increase with increasing soy oil (linear, P < 0.01; quadratic, P = 0.06) or the soy oil/crude glycerol blend (linear, P < 0.01; quadratic, P = 0.09). Nitrogen digestibility tended (P = 0.07) to decrease in pigs fed crude glycerol compared with pigs fed the soy oil treatments. Apparent digestibility of GE tended (P = 0.08) to be greater in the pigs fed soy oil compared with pigs fed the soy oil/crude glycerol blends. In conclusion, adding crude glycerol to the diet before pelleting increased pellet durability and improved feed mill production efficiency. The addition of 3 or 6% crude glycerol, soy oil, or a blend of soy oil and glycerol in diets for 11- to 27-kg pigs tended to increase ADG. For pigs fed crude glycerol, this was a result of increased ADFI, whereas, for pigs fed soy oil or the soy oil/crude glycerol, the response was a result of increased G:F.
authors.affiliation: Department of Animal Sciences and Industry, College of Veterinary Medicine, Kansas State University, Manhattan 66506-5601, USA.
authors.forename: C N
authors.initials: CN
authors.lastname: Groesbeck
authors.forename: L J
authors.initials: LJ
authors.lastname: McKinney
authors.forename: J M
authors.initials: JM
authors.lastname: Derouchey
authors.forename: M D
authors.initials: MD
authors.lastname: Tokach
authors.forename: R D
authors.initials: RD
authors.lastname: Goodband
authors.forename: S S
authors.initials: SS
authors.lastname: Dritz
authors.forename: J L
authors.initials: JL
authors.lastname: Nelssen
authors.forename: A W
authors.initials: AW
authors.lastname: Duttlinger
authors.forename: A C
authors.initials: AC
authors.lastname: Fahrenholz
authors.forename: K C
authors.initials: KC
authors.lastname: Behnke
mesh_terms: D000821:Animal Feed; D000824:Animal Nutritional Physiological Phenomena; D000818:Animals; D004435:Eating / Q000502:physiology*; D005243:Feces / Q000737:chemistry; D005990:Glycerol / Q000008:administration & dosage* / Q000378:metabolism; D010865:Pilot Projects; D013552:Swine / Q000254:growth & development* / Q000378:metabolism*
chemical_list: D005990:Glycerol