Effect of crop retention time and acidification of the feed on phytase efficacy in broiler chickens

Figures & data

Table 1. Composition and nutrient content of the basal diets used in the in vitro trial and broiler experiment (g/kg as fed unless otherwise stated)

Ingredients	In vitro	Broiler experiment
Wheat	371.8	361
Wheat bran	350	310
Soybean meal (466 g/kg CP)	147	121
Rape seed meal (340 g/kg CP)	-	120
Maize gluten	37	-
Soy oil	-	58
Rapeseed oil	63	-
Limestone	12.5	12
Sodium chloride	-	2
Titanium dioxide	-	5
Mineral and vitamin premix	5.3	4^a
L-threonine	1.3	1
DL-methionine	2.2	2
L-lysine	4.3	3
Sodium bicarbonate	5	0.9
Cholin chloride	0.4	-
Enzyme	0.2	0.05^b
Nutrient composition
Calculated gross energy MJ/kg		12.01
Calculated phytate P		4.0
Analysed InsP6		19.9
Analysed crude protein		186.4
Analysed starch		224.1
Analysed total P		5.29
Analysed Ca		7.36

^aMineral and vitamin premix provided the following per kg diet: 2.57 mg retinol, 0.13 mg cholecalciferol, 56.1 mg tocopherol, 3.6 mg menadione, 2.4 mg thiamine, 9 mg riboflavin, 36 mg niacin, 7.2 mg pyridoxine, 0.012 mg cobalamin, 36 mg pantothenic acid, 1.8 mg folic acid, 0.24 mg biotin, 85.7 mg Mn, 49.4 mg Zn, 45.4 mg Fe, 6.76 mg Cu, 0.32 mg Se, 0.86 mg I.

^bEnzyme Rovabio® Excel AP, Adisseo, France, provided xylanase and ß-glucanase obtained from a fermentation broth of Penicillium funiculosum.

Table 2. Released phosphorus (mg/g feed) from test feed in the negative control with no exogenous phytase added and with four different commercial phytases, at four different pH levels and five different incubation times (in vitro trial)

Incubation (minutes)	pH	Negative control	Phytase A^A	Phytase B^A	Phytase C^A	Phytase D^A	Average^B
10	6.7	0.9^k	4.2 ^c	3.1 ^g	3.6 ^f	1.8^i	3.2 ^f
20	6.7	1.2^ij	4.3^bc	3.3^fg	3.7^ef	2.2 ^h	3.4^ef
30	6.7	1.5^gh	4.6^abc	3.5 ^f	4.1^bcde	2.4 ^h	3.6^def
45	6.7	1.8 ^f	4.5^abc	3.6^ef	4.0 ^cdef	2.9 ^g	3.7 ^cde
60	6.7	2.0^e	4.4^bc	3.6^ef	3.9^fde	3.0 ^g	3.7^cde
10	5.5	1.3^hi	4.6^ab	3.9^de	4.1^bcde	3.5 ^f	4.0^bcd
20	5.5	1.9^ef	4.5^abc	4.1^bcd	4.5^ab	3.8^e	4.2^abc
30	5.5	2.2^d	4.6^abc	4.0 ^cd	4.3^abcd	3.9^de	4.2^abc
45	5.5	2.8^b	4.8^a	4.1^bcd	4.5^ab	4.0^de	4.4^ab
60	5.5	3.1^a	4.5^abc	4.1^bcd	4.3^abcd	4.2 ^cd	4.3^ab
10	4.5	1.1^jk	4.6^abc	4.1^bcd	4.3^abcd	4.2 ^cd	4.3^ab
20	4.5	1.6 ^g	4.4^bc	4.3^bc	4.4^abc	4.5^abc	4.4^ab
30	4.5	1.9^ef	4.6^abc	4.3^bc	4.4^abc	4.6^ab	4.5^ab
45	4.5	2.4 ^c	4.8^a	4.1^bcd	4.4^abcd	4.7^ab	4.5^ab
60	4.5	3.0^ab	4.9^a	4.3^bc	4.4^abcd	4.7^ab	4.5^ab
10	3.5	0.8 ^l	4.4^bc	4.3^bc	4.4^abc	4.4^bc	4.4^ab
20	3.5	0.9^kl	4.6^ab	4.1^bcd	4.3^abcd	4.5^abc	4.4^ab
30	3.5	1.0^jk	4.8^a	4.4^abc	4.6^ab	4.6^ab	4.6^a
45	3.5	1.4 ^h	4.6^abc	4.7^a	4.6^ab	4.8^a	4.6^a
60	3.5	1.6 ^g	4.6^ab	4.5^ab	4.7^a	4.7^ab	4.6^a
	6.7	1.5 ^c	4.4^b	3.4^d	3.9 ^c	2.5 ^c	3.5 ^c
	5.5	2.3^a	4.6^a	4.0 ^c	4.3^b	3.9^b	4.2^b
	4.5	2.0^b	4.6^a	4.2^b	4.4^b	4.5^a	4.4^a
	3.5	1.1^d	4.6^a	4.4^a	4.5^a	4.6^a	4.5^a
10		1.0^e	4.5^b	3.8 ^c	4.1^b	3.5 ^c	4.0^b
20		1.4^d	4.5^b	3.9^bc	4.3^ab	3.8^b	4.1^ab
30		1.7^c	4.6^a	4.0^ab	4.3^a	3.9^b	4.2^a
45		2.1^b	4.7^a	4.1^a	4.3^a	4.0^a	4.3^a
60		2.4^a	4.6^a	4.1^a	4.3^a	4.1^a	4.3^a
√MSE^C		0.05	0.15	0.15	0.19	0.15	0.45
P-value
pH		<0.001	<0.001	<0.001	0.004	<0.001	<0.001
Time		<0.001	<0.001	<0.001	<0.001	<0.001	<0.001
Time x pH		<0.001	0.001	0.002	0.041	<0.001	0.903

^AThe phytases had the following donor organisms: Escherichia coli, Buttiauxella sp., Aspergillus niger and Citrobacter braakii; ^BAverage of all phytases used; ^C√MSE: square root of means square error in the analysis of variance; ^a–k Means within column without common letters are significantly different at P < 0.05.

Table 3. Effects of intermittent feeding, formic acid and phytase addition on the performance of broilers from d 11 to 36

Feeding regimen	Phytase	Acid	FI^A	BWG^B	FCR^C
Ad libitum		No	4073	2400	1.70
Ad libitum		Yes	4043	2373	1.70
Intermittent		No	3890	2292	1.70
Intermittent		Yes	3808	2256	1.69
Ad libitum	No		3999	2311	1.73
Ad libitum	Yes		4116	2462	1.67
Intermittent	No		3795	2213	1.72
Intermittent	Yes		3904	2334	1.67
	Yes	No	4030	2396	1.68
	Yes	Yes	3990	2401	1.66
	No	No	3933	2296	1.72
	No	Yes	3861	2229	1.73
Ad libitum			4058^a	2388^a	1.70
Intermittent			3849^b	2274^b	1.69
	No		3897^b	2262^b	1.72^a
	Yes		4010^a	2398^a	1.67^b
		No	3981	2346	1.70
		Yes	3926	2315	1.70
√MSE^D			130.2	80.9	0.042
p-value
Feeding regimen			<0.001	<0.001	0.413
Phytase			<0.001	<0.001	<0.001
Acid			0.059	0.090	0.853
Feeding x phytase			0.890	0.410	0.329
Feeding x acid			0.380	0.811	0.509
Phytase x acid			0.569	0.057	0.063
Feeding x phytase x acid			0.580	0.950	0.579

^AFeed intake (g) d 11–36; ^BBody weight gain (g) d 11–36; ^CFeed conversion ratio, calculated as feed:gain; ^DSquare root of means square error in the analysis of variance

^a,bMeans within column without common letters are significantly different at P < 0.05.

Table 4. The pH in crop of intermittently fed chickens with or without formic acid addition to the feed at 80, 160 and 240 min after the start of feeding.^A

Time after start of feeding	Acid	pH
80 min	No	5.6
80 min	Yes	4.5
160 min	No	5.3
160 min	Yes	4.5
240 min	No	4.2
240 min	Yes	4.1
80 min		5.0^a
160 min		4.9^a
240 min		4.1^b
	No	5.2^a
	Yes	4.4^b
√MSE^B		0.64
p-value
Time		<0.001
Acid		<0.001
Time x acid		0.054

^AThe pH values were based on 20 crops with acid and 18 without acid at 80 min, 15 with acid and 15 without acid at 160 min, and 11 with acid and 7 without acid at 240 min; ^BSquare root of means square error in the analysis of variance; ^a,bMeans within column without common letters are significantly different at P < 0.05.

Table 5. Effects of intermittent feeding, formic acid and phytase addition on bone mineralisation and P and starch digestibility coefficients in selected segments of the intestine

Feeding regimen	Phytase	Acid	Tibia ash g/kg^A	g P in tibia/kg BW	Jejunal P digestibility	Ileal P digestibility	P retention	Ileal starch digestibility
Ad libitum		No	408.6	0.14	0.35 ^c	0.47	0.28	0.93
Ad libitum		Yes	411.7	0.15	0.45^b	0.55	0.29	0.91
Intermittent		No	420.9	0.15	0.56^a	0.53	0.39	0.93
Intermittent		Yes	408.6	0.15	0.54^ab	0.55	0.41	0.93
Ad libitum	No		386.4	0.13	0.23	0.36 ^c	0.26	0.92
Ad libitum	Yes		433.9	0.16	0.57	0.66^a	0.31	0.93
Intermittent	No		394.2	0.13	0.41	0.46^b	0.36	0.93
Intermittent	Yes		435.2	0.16	0.68	0.62^a	0.43	0.93
	Yes	No	439.3	0.16	0.58	0.60	0.36	0.93
	Yes	Yes	429.8	0.16	0.67	0.69	0.37	0.92
	No	No	390.2	0.13	0.32	0.40	0.30	0.92
	No	Yes	390.5	0.13	0.32	0.42	0.32	0.92
Ad libitum			410.1	0.14	0.40^b	0.51	0.28^b	0.92
Intermittent			414.7	0.15	0.55^a	0.54	0.40^a	0.93
	No		390.3^b	0.13^b	0.32^b	0.41^b	0.31^b	0.92
	Yes		434.5^a	0.16^a	0.63^a	0.64^a	0.37^a	0.93
		No	414.7	0.14	0.45	0.50	0.33	0.93
		Yes	410.1	0.15	0.49	0.55	0.34	0.92
√MSE^B			2.75	0.020	0.121	0.128	0.052	0.045
p-value
Feeding regimen			0.459	0.230	<0.001	0.318	<0.001	0.591
Phytase			<0.001	<0.001	<0.001	<0.001	<0.001	0.502
Acid			0.459	0.913	0.121	0.061	0.142	0.274
Feeding x phytase			0.599	0.913	0.243	0.025	0.314	0.641
Feeding x acid			0.213	0.275	0.019	0.298	0.489	0.288
Phytase x acid			0.426	0.230	0.078	0.226	0.832	0.876
Feeding x phytase x acid			0.903	0.083	0.667	0.946	0.117	0.773

^Ag/kg of tibia dry matter; ^BSquare root of means square error in the analysis of variance; ^a,b,cMeans within column without common letters are significantly different at P < 0.05.

Figure 1. InsP₆ degradation (%) in the crop digesta 80, 160 and 240 min after start of feeding. The InsP values were based on 10 NC, 7 NC+phy, 10 NC+acid and 9 NC+phy+acid crops at 80 min, 8 NC, 4 NC+phy, 8 NC+acid and 5 NC+phy+acid crops at 160 min, and 3 NC, 1 NC+phy, 7 NC+acid and 2 NC+phy+acid crops at 240 min. Treatment means within time with different letters are significantly different (P < 0.05), √MSE is 22.89 for 80 and 18.52 for 160 min. The InsP₆ values for 240 min have not been included in the statistics

Table 6. Effect of acid and phytase addition on the concentration of different inositol phosphate isomers (InsPs) (µmol/g DM) in the crop digesta of intermittently fed birds at 80 and 160 min after the start of feeding

			80 min after start of feeding^A
Phytase	Acid		InsP3^B	InsP4^C	Ins(1,2,3,4,6)P5	Ins(1,2,3,4,5)P5	Ins(1,2,4,5,6)P5	InsP6
No	No		0.0	0.5 ^c	0.7	1.1	1.0	23.7
No	Yes		0.0	0.3 ^c	0.7	1.3	1.1	23.6
Yes	No		1.6	3.2^b	0.3	0.7	0.7	17.7
Yes	Yes		3.0	7.4^a	0.1	1.3	0.5	10.3
No			0.0^b	0.4^b	0.7^a	1.2	1.1^a	23.6^a
Yes			2.4^a	5.6^a	0.2^b	1.1	0.6^b	13.6^b
	No		0.7	1.6^b	0.5	0.9^b	0.9	21.2
	Yes		1.4	3.7^a	0.5	1.3^a	0.9	17.3
√MSE^D			1.09	2.22	0.13	0.46	0.28	6.03
p-value
Phytase	<0.001			<0.001	<0.001	0.453	<0.001	<0.001
Acid			0.057	0.010	0.236	0.007	0.794	0.078
Phytase x acid			0.057	0.007	0.107	0.160	0.161	0.079
			160 min after start of feeding^A
Phytase	Acid		InsP3^B	InsP4^C	Ins(1,2,3,4,6)P5	Ins(1,2,3,4,5)P5	Ins(1,2,4,5,6)P5	InsP6
No	No		0.2 ^c	0.8^bc	0.9^a	1.2	1.0^a	23.7^a
No	Yes		0.0 ^c	0.5 ^c	0.9^a	1.7	1.1^a	23.5^a
Yes	No		1.5^b	3.3^b	0.4^b	0.8	0.6^b	13.4^b
Yes	Yes		6.6^a	11.2^a	0.0^c	0.8	0.2^b	3.9 ^c
No			0.1^b	0.7^b	0.9^a	1.4^a	1.1^a	23.6^a
Yes			4.3^a	7.7^a	0.2^b	0.8^b	0.4^b	8.1^b
	No		0.6^b	1.6^b	0.7	1.1	0.9	20.3^a
	Yes		2.6^a	4.7^a	0.6	1.3	0.8	16.0^b
√MSE^D			0.83	1.82	0.22	0.49	0.27	4.87
p-value
Phytase	<0.001			<0.001	<0.001	0.006	<0.001	<0.001
Acid	<0.001			<0.001	0.060	0.313	0.207	0.028
Phytase x acid		<0.001		<0.001	0.046	0.302	0.050	0.034

^AThe InsP values were based on 10 NC, 7 NC+phy, 10 NC+acid and 9 NC+phy+acid crops at 80 min and 8 NC, 4 NC+phy, 8 NC+acid and 5 NC+phy+acid crops at 160 min; ^BAt least one of the following isomers: Ins(1,2,6)P₃, Ins(1,4,5)P₃, Ins(2,4,5)P₃, Ins(1,4,6)P₃ and Ins(2,3,5)P₃; ^CAt least one of the following isomers Ins(1,2,3,4)P₄ and Ins(1,2,5,6)P₄; ^DSquare root of means square error in the analysis of variance; ^a,b,c Means within column without common letters are significantly different at P < 0.05.