Table 6.

Effect of diet complexity and threonine supplementation on microbial metabolites and pH in jejunum and colon digesta¹

	Complex		Simple			P-value2
Item	STD Thr	SUP Thr	STD Thr	SUP Thr	SEM	Diet	Thr	Diet × Thr
Jejunal SCFA3, mmol/L3
Acetate	15.8	18.8	16.0	11.9	4.09	0.389	0.897	0.362
Propionate	0.6	0.3	0.7	1.1	0.38	0.156	0.874	0.323
Butyrate	0.5	0.5	0.4	0.3	0.13	0.155	0.738	0.598
Isovalerate	1.3	1.2	1.4	0.8	0.28	0.600	0.177	0.309
Valerate	0.1	0.1	0.1	0.1	0.05	0.643	0.739	0.255
Lactate	11.1	8.2	10.9	11.2	2.79	0.598	0.628	0.564
BCFA4	1.4	1.4	1.6	0.9	0.32	0.567	0.208	0.286
Total VFA	18.2	20.9	18.6	14.2	4.43	0.450	0.836	0.395
Total SCFA	29.3	29.2	29.5	25.3	4.20	0.549	0.589	0.607
Colonic SCFA, mmol/L
Acetate	113.6x	87.1y	106.8xy	110.2xy	7.17	0.238	0.097	0.036
Propionate	72.6	52.9	64.7	74.7	6.38	0.254	0.422	0.020
Isobutyrate	1.5	2.0	1.9	1.2	0.51	0.651	0.842	0.242
Butyrate	35.9	32.9	37.8	46.7	3.94	0.043	0.430	0.120
Isovalerate	2.6	3.4	3.0	2.1	0.77	0.515	0.921	0.224
Valerate	12.8	10.0	10.1	14.4	2.06	0.670	0.692	0.082
Lactate	21.5	28.3	9.7	20.4	11.71	0.376	0.434	0.859
BCFA4	16.9	15.5	15.0	17.6	2.27	0.947	0.778	0.348
Total VFA	239.0xy	188.4y	224.3xy	249.2x	14.69	0.106	0.359	0.011
Total SCFA	260.5	216.7	234.0	269.5	20.22	0.493	0.829	0.046
Ammonia N, mg/L
Jejunum	73.6y	93.8xy	158.5x	76.3y	18.82	0.067	0.091	0.007
Colon	254.2	320.3	271.0	301.4	41.89	0.979	0.231	0.653
pH
Jejunum	6.42	6.05	6.02	6.28	0.151	0.561	0.705	0.033
Colon	5.79	5.95	5.83	5.65	0.107	0.216	0.927	0.090

¹STD Thr, the standard NRC (2012) level of SID Thr (0.79%); SUP Thr, 15% over the SID Thr requirement. Data represented as least square means of 7 to 9 pigs.

²Diet, main effect of diet complexity; Thr, main effect of the levels of dietary Thr supplementation; Diet × Thr, interactive effect of diet complexity and Thr supplementation.

³Isobutyrate was not detected.

⁴Branched chain fatty acids = isobutyrate + isovalerate + valeric acid.

^x,yWithin a row, means with different superscripts differ (P < 0.05).