Limestone particle size and Aspergillus niger phytase in the diet of older hens

Figures & data

Table 1. Composition of the hen diets.

	FL + CL^a	CL^a
Ingredient, g/kg
Wheat	240	240
Maize	360.9	360.9
Soybean meal	280	280
Rapeseed oil	20	20
Monocalcium phosphate	3.6	3.6
Sodium chloride	2	2
Fine-grained limestone	43	–
Coarse-grained limestone	43	86
l-Lysine hydrochloride	1	1
dl-Methionine	1.5	1.5
Vitamin-mineral premix^b	5	5
Analysed nutrient content, g/kg
AMEN by calculation, MJ/kg	11.51	11.46
Crude protein	170.1	170.4
Ca	34.3	34.6
TP	4.36	4.39
PP	2.56	2.60
NPP	1.80	1.79

^a FL = fine limestone; CL = coarse limestone; other experimental diets were supplemented with 350 FTU/kg of 3-phytase NATUPHOS^®.

^b Vitamin-mineral premix provided per kg of diet: retinyl acetate, 3.0 mg; vitamin D₃, 3000 U; vitamin E, 30 mg; niacin, 25 mg; Ca pantothenate, 8 mg; thiamine, 2.0 mg; riboflavin, 5 mg; pyridoxine, 4 mg; folic acid, 0.5 mg; biotin, 0.075 mg; cobalamin, 0.01 mg; choline Cl, 250 mg; menadione, 2.0 mg; betaine, 100 mg; butylated hydroxytoluene, 7.5 mg; ethoxyquin, 5.6 mg; butylhydroxyanisole, 1 mg; DL-methionine, 0.7 g; Mn, 70 mg; Zn, 50 mg; Fe, 40 mg; Cu, 6 mg; I, 1 mg; Co, 0.3 mg; Se, 0.2 mg;.

ME_N: metabolisable energy; TP : total phosphorus; PP : phytate phosphorus; NPP : nonphytate phosphorus.

Table 2. The effect of phytase and limestone particle size on performance.

Phytase, F; FTU/kg	0		350			Probability
Limestone, L	FL + CL	CL	FL + CL	CL	SEM	F	L	F × L
Hen-day egg production, %	84.9^ab	82.5^b	82.7^b	88.6^a	0.88	ns	ns	0.018
Egg weight, g	66.7	66.5	66.4	65.9	0.19	ns	ns	ns
Egg mass, g/day/hen	56.1	54.9	54.7	57.8	0.60	ns	ns	ns
Feed intake, g/day/hen	116.2^b	116.9^b	117.4^a	116.3^b	0.57	ns	ns	0.001
Feed intake, g/egg	137.8^b	142.1^b	144.5^a	132.3^b	1.93	ns	ns	0.001
Feed conversion ratio, g/g	2.08^b	2.15^ab	2.30^a	2.03^b	0.030	ns	ns	0.005

FTU : phytase units; FL : fine limestone; CL : coarse limestone; ns : non-significant.

^a,b Means in the same row with different superscripts differ significantly.

Table 3. The effect of phytase and limestone particle size on egg quality.

Phytase, F; FTU/kg	0		350			Probability
Limestone, L	FL + CL	CL	FL + CL	CL	SEM	F	L	F × L
Haugh units	79.8	79.9	82.7	77.4	0.69	ns	0.039	ns
Albumen percentage, %	64.4	64.5	63.9	64.4	0.18	ns	ns	ns
Albumen index, %	8.0	7.6	8.3	7.2	0.15	ns	0.008	ns
Yolk percentage, %	25.8	25.4	25.9	25.2	0.16	ns	ns	ns
Yolk index, %	44.6	43.1	44.7	43.7	0.24	ns	0.013	ns
Shell thickness
Blunt end, μm	347	359	364	370	3.0	0.015	ns	ns
Equator, μm	356	363	371	380	3.0	0.009	ns	ns
Sharp end, μm	359	364	374	380	3.2	0.015	ns	ns
Average, μm	354	362	370	377	2.8	0.006	ns	ns
Shell breaking strength, g/cm^2	3893	3826	4165	4320	78.4	0.017	ns	ns
Shell index, g/100 cm^2	8.6	8.7	8.9	9.1	0.06	0.003	ns	ns
Shell percentage, %	9.8	10.0	10.2	10.4	0.07	0.007	ns	ns
Shell ash content, g/kg DM	953^ab	954^ab	956^a	952^b	0.6	ns	ns	0.047
Shell Ca content, g/kg DM	382	370	378	361	2.1	ns	≤0.001	ns
Shell P content, g/kg DM	1.21	1.32	1.22	1.14	0.025	ns	ns	ns

FTU : phytase units; FL : fine limestone; CL : coarse limestone; ns : non-significant.

^a,bMeans in the same row with different superscripts differ significantly.

Figure 1. DGGE analysis of the ileum* compared by the Ward cluster analysis**. *Sample nos. 1–12: control group (CL without F); sample nos. 13–24: treatment (CL with F Natuphos^®); **Ochiai band-based similarity coefficient; optimisation, 1%; tolerance, 0.5%; and fuzzy logic on (BioNumerics, Applied Maths, Sint-Martens-Latem, Belgium).

Table 4. The effect of phytase and limestone particle size on calcium and phosphorus digestibility in the ileum.

Phytase, FTU/kg	0	350
Limestone	CL	CL	SEM	Probability
Calcium, %	49.9	53.0	4.44	ns
Phosphorus, %	42.9	46.8	2.32	ns

FTU : phytase units; CL : coarse limestone; ns : non-significant.