Table 3.

Least square means of interactive effects of Zn and Cu sources and phytase on growth performance in nursery pigs

	Main effects						Interactions
							ZnO				Zn-MHACb
	Zn sources		Cu sources		Phytasea		CuSO4		Cu-MHACc		CuSO4		Cu-MHAC
Items	ZnO	Zn-MHAC	CuSO4	Cu-MHAC	No	Yes	No	Yes	No	Yes	No	Yes	No	Yes
BW, kg
Days 0	5.7	5.7	5.7	5.7	5.7	5.7	5.7	5.7	5.7	5.7	5.7	5.8	5.7	5.7
Days 14	8.4	8.2	8.3	8.4	8.2	8.5	8.3	8.6	8.4	8.5	8.0	8.2	8.2	8.5
Days 28	15.2	15.1	15.1	15.3	14.6	15.8	14.6	15.9	14.3	16.1	14.7	15.3	14.8	15.9
Days 42	22.3	22.2	21.9	22.6	20.7	23.9	20.3	23.7	20.8	24.5	20.4	23.4	21.2	24.0
ADG, g/d
Days 0–14	195	179	183	191	178	196	185	206	188	199	163	178	175	200
Days 14–28	484	495	488	491	457	522	451	521	425	539	478	503	474	525
Days 28–42	505	507	487	525	432	579	403	558	455	603	409	577	461	579
Days 0–28	340	337	336	341	317	359	318	363	307	371	321	340	324	363
Days 0–42	400	399	391	408	361	438	350	434	364	453	354	424	375	441
ADFI, g/d
Days 0–14	286	269	276	279	276	279	281	296	283	283	269	257	272	277
Days 14–28d	628	622	629	621	611	640	605	666	579	662	626	619	632	611
Days 28–42e	952	970	934	988	894	1,027	825	1,020	910	1,052	867	1,023	974	1,013
Days 0–28	456	445	453	449	442	459	443	481	429	472	448	438	450	444
Days 0–42	614	615	609	620	587	643	568	656	577	658	584	629	618	628
G:F, g/g
Days 0–14	0.68	0.66	0.66	0.68	0.64	0.70	0.65	0.69	0.66	0.70	0.60	0.68	0.64	0.72
Days 14–28f	0.77	0.80	0.78	0.80	0.76	0.82	0.75	0.78	0.74	0.82	0.77	0.81	0.76	0.87
Days 28–42	0.53	0.52	0.52	0.53	0.48	0.56	0.49	0.55	0.50	0.58	0.47	0.56	0.47	0.57
Days 0–28	0.75	0.76	0.74	0.76	0.72	0.78	0.72	0.75	0.72	0.79	0.72	0.77	0.73	0.82
Days 0–42	0.65	0.65	0.64	0.66	0.62	0.68	0.62	0.66	0.63	0.69	0.60	0.67	0.61	0.70

^aNo and yes represent 0 and 500 FTU/kg phytase in the diets, respectively.

^bZn-MHAC represents Zn methionine hydroxy analogue chelate (MINTREX Zn), which is manufactured by Novus International Inc., St. Charles, MO.

^cCu-MHAC represents Cu methionine hydroxy analogue chelate (MINTREX Cu), which is manufactured by Novus International Inc., St. Charles, MO.

^dThere was a significant interaction (P = 0.03) between Zn sources and phytase. Specifically, when ZnO was used as the Zn source, phytase supplementation increased ADFI during phase 2 by 12.16% (664 vs. 592 g/d) compared with no phytase supplementation, whereas when Zn-MHAC was used as the Zn source, phytase supplementation reduced ADFI during phase 2 by 2.23% (615 vs. 629 g/d) compared with no phytase supplementation.

^eThere tended to be an interaction (P = 0.06) between Cu sources and phytase. Specifically, when CuSO₄ was used as the Cu source, phytase supplementation increased ADFI during phase 3 by 20.69% (1,021 vs. 846 g/d) compared with no phytase supplementation, whereas when Cu-MHAC was used as the Cu source, phytase supplementation increased ADFI during phase 3 by 9.66% (1,033 vs. 942 g/d) compared with no phytase supplementation.

^fThere tended to be an interaction (P = 0.09) between Cu sources and phytase. Specifically, when Cu sulfate was used as the Cu source, phytase supplementation significantly increased G:F during phase 2 by 5.26% (0.80 vs. 0.76 g/g) compared with the group with no phytase supplementation, whereas when Cu-MHAC was used as the Cu source, phytase supplementation significantly increased G:F during phase 2 by 12% (0.84 vs. 0.75 g/g) compared with the group with no phytase supplementation.