180 Effects of copper hydroxychloride and distillers dried grains with solubles on intestinal microbial protein concentration and digestibility of energy, crude protein, and fat by growing pigs

An experiment was conducted to test the hypothesis that Cu hydroxychloride (IntelliBond CII, Micronutrients, LLC, Indianapolis, IN) improves nutrient digestibility and alters microbial protein concentration in the gastrointestinal tract of pigs. Twenty-four barrows (33.3 ± 3.4 kg) that had a T-cannula installed in the distal ileum were allotted to a 2 × 2 factorial design with 2 levels of distillers dried grains with solubles (DDGS; 0 or 45%) and 2 levels of supplemental Cu from Cu hydroxychloride (0 or 150 mg/kg). Pigs were allotted to a 2-period switch back design with 4 diets and 6 replicate pigs per diet in each period resulting in 12 replicate pigs per diet for the 2 periods. For each period, feces were collected on d 10, 11, and 12, and ileal digesta were collected for 8 h on d 13 and 14. Data were analyzed in a 2 × 2 factorial arrangement using SAS. Fixed effects included Cu, DDGS, and the interaction between Cu and DDGS, whereas random effects included pig and period. Results indicated that inclusion of 45% DDGS to diets reduced (P < 0.05) the apparent ileal digestibility (AID) and the apparent total tract digestibility (ATTD) of dry matter, gross energy, and crude protein (Table 1), and increased (P < 0.05) the microbial protein concentration in the hindgut. The AID and ATTD of crude protein were not affected by dietary Cu concentrations, but the AID and ATTD of fat were greater (P < 0.05) in diets with Cu hydroxychloride than diets without Cu hydroxychloride. There was a reduction (P < 0.05) in microbial protein and concentration of volatile fatty acids in feces when diets were supplemented with Cu hydroxychloride. In conclusion, supplementation of Cu hydroxychloride to diets improved AID and ATTD of fat and reduced concentration of microbial protein in the hindgut.