Diet Nutrient Digestibility and Growth Performance of Weaned Pigs Fed Barley Differing in Fermentable Starch and Fiber

Fermentable starch and fiber in hull-less barley grain are attractive energy sources for weaned pigs due to benefits on gut health. Steam-explosion processing may open the fiber matrix of hulls, increasing the nutritional value of hulled barley. In total, 220 weaned pigs (8.5 kg) were fed 1 of 5 diets containing 59−64% cereal grain: 1) low-fermentable wheat (LFW); 2) low-fermentable hulled barley (LFB); 3) LFB steam-exploded (LFB-E; 1.2 MPa−120s); 4) high-fermentable high β-glucan hull-less barley (HFB); or 5) high-fermentable high amylose hull-less barley (HFA). Diets provided 2.4 and 2.3 Mcal net energy (NE)/kg, 5.5 and 5.1 g standardized ileal digestible lysine/Mcal NE for phase 1 (d 1–14) and phase 2 (d 15–28), respectively. In phase 1, the apparent total tract digestibility (ATTD) of gross energy (GE) and crude protein (CP) was greatest for LFW, intermediate for HFB, followed by LFB-E, LFB and HFA. In phase 2, the ATTD of GE was greater (P < 0.05) for LFW and HFB than LFB and LFB-E, and the ATTD of CP was greatest for LFW, intermediate for HFB, followed by LFB, HFA and LFB-E. Predicted NE value was greatest for LFW, intermediate for LFB-E, followed by HFBB, LFB and HFA in phase 1, and lowest for HFA among diets in phase 2. For d 1–28, average daily feed intake (ADFI) and average daily gain did not differ among diets, but gain:feed (G:F) for LFB-E was lower (P < 0.05) than other 4 diets. Pigs fed LFB and LFW had firmer (P < 0.05) feces than pigs fed HFB, HFA and LFB-E. In specific weeks, G:F was lower (P < 0.05) for LFB-E than LFW for d 1–14 and ADFI was greater (P < 0.05) for LFB-E than HFA for d 22–28. In conclusion, feeding barley instead of wheat grain to weaned pigs reduced nutrient digestibility, and fermentable starch and fiber reduced feces consistency. Steam-explosion did not increase the nutritional value of barley. However, feeding hulled or hull-less barley to replace wheat did maintain growth performance in weaned pigs.

Key words: barley, fiber, starch.

Presented at the 2021 Animal Nutrition Conference of Canada. For information on the next edition, click here.