Table 5.

Intestinal microbial protein concentrations (mg/g, DM basis) and rate of fermentation of volatile fatty acids in ileal digesta and feces of pigs fed experimental diets¹

Item	No added Cu2		150 mg/kg Cu2			P-value
	–DDGS3	45% DDGS	–DDGS	45% DDGS	SEM	DDGS	Cu	DDGS × Cu
Ileal digesta
Microbial protein	23.38	19.91	19.09	19.37	2.36	0.501	0.312	0.430
Volatile fatty acids (µmol/100 µmol)
Acetate	93.13	93.49	91.22	94.91	1.86	0.200	0.868	0.276
Propionate	2.54	3.66	3.88	2.88	1.08	0.954	0.797	0.329
Butyrate	3.63	1.59	3.93	1.08	0.69	<0.001	0.847	0.453
Isobutyrate	0.53	0.78	0.68	0.74	0.07	0.019	0.434	0.139
Isovalerate	0.16	0.37	0.28	0.27	0.07	0.170	0.874	0.123
Valerate	0.01	0.11	0.01	0.12	0.07	0.010	0.885	0.897
Total [VFA3], µmol/g, DM basis	7.88	9.05	7.88	7.00	1.10	0.866	0.229	0.230
Feces
Microbial protein	169.32	195.15	142.08	182.07	9.63	0.002	0.046	0.469
Volatile fatty acids (µmol/100 µmol)
Acetate	69.66	75.70	61.75	75.10	1.73	0.006	0.096	0.277
Propionate	20.27	16.17	25.08	16.69	2.52	0.005	0.215	0.317
Butyrate	1.15	1.09	1.25	1.12	0.10	0.384	0.523	0.718
Isobutyrate	5.56	4.15	7.48	4.12	0.72	0.002	0.195	0.180
Isovalerate	1.34	1.18	1.60	1.27	0.18	0.168	0.342	0.644
Valerate	2.02	1.71	2.84	1.70	0.42	0.067	0.300	0.280
Total [VFA], µmol/g, DM basis	12.36	10.68	10.06	10.42	0.67	0.333	0.065	0.140

¹Data are least squares means of 12 observations for treatments without DDGS and 11 observations for treatments with DDGS.

²Diets containing added Cu were fortified with 150 mg/kg of Cu as Cu hydroxychloride (IntelliBond C^II; Micronutrients USA, Indianapolis, IN).

³DDGS, distillers dried grains with solubles; VFA, volatile fatty acids.