Effect of feeding wheat- or barley-based diets with low or and high nutrient density on nutrient digestibility and growth performance in weaned pigs

Barley grain is commonly fed to growing-finishing pigs as the major cereal feed energy source in western Canada. However, its nutritional value for weaned pigs is poorly characterized. Formulating low nutrient dense diets may reduce feed cost. Weaned pigs may be able to maintain growth performance by adjusting feed intake to meet nutrient requirement. Four diets based on either 644 g wheat/kg or 676 g barley/kg with either 9.63 or 10.0 MJ net energy (NE)/kg were fed to 208 weaned pigs (9.0 kg) as a 2 × 2 factorial arrangement with 13 replicate pens per diet. Diets were formulated to have 1.07 g standardised ileal digestible lysine/MJ NE and were fed for 21 days. Feed added, feed remaining and pig body weight were measured weekly to calculate pen average daily feed intake (ADFI), average daily gain (ADG) and feed efficiency (G:F). Faeces were collected to calculate diet apparent total tract digestibility (ATTD) of dry matter (DM), gross energy (GE) and crude protein (CP). Compared with wheat-based diets, feeding barley-based diets reduced (P < 0.001) ATTD of DM, GE and CP by 2.7, 3.0 and 4.4%, respectively. Compared with high nutrient density (ND) diets, feeding low ND diets reduced (P < 0.001) ATTD of DM, GE and CP by 2.6, 1.8 and 2.3%, respectively. For the entire trial (day 0-21), feeding barley increased (P < 0.001) ADG by 41.2 g/d and G:F by 0.04 compared with feeding wheat but did not affect ADFI (P > 0.05). Diet ND did not affect (P > 0.05) ADFI, ADG or G:F. In conclusion, feeding barley as cereal energy for weaned pigs instead of wheat grain may increase growth performance. Reducing dietary NE value by 0.37 MJ/kg while maintaining the SID AA content/NE ratio did not affect growth performance in weaned pigs.