Efficacy of maize differing in particle size in low-density protein diets fed to broilers from day 1 to 21 of age

Figures & data

Table 1. Ingredients (%) and calculated nutritional composition of basal starter and grower with analysed nutrient values given in brackets where available.

Ingredient	Basal stater (days 0–7)	Basal grower (days 8–21)
Wheat	42.94	46.50
Soybean meal	23.30	34.50
Rapeseed (whole)	–	6.60
Maize	15.00	–
Maize DDGS	–	4.76
Wheat feed	5.00	–
Barley	5.00	–
Sunflower meal	4.00	–
Soyabean oil	1.20	3.45
Calcium carbonate	0.97	0.85
Monocalcium phosphate	0.97	–
Dicalcium phosphate	–	1.85
Salt	0.27	0.30
Lysine-HCl	0.37	0.39
Methionine-DL	0.26	0.30
Premix^1	0.50	0.50
Sodium bicarbonate	0.10	–
Elancoban G200	0.05	–
L-Threonine	0.03	–
Roxazyme G2G liquid 35.7%	0.03	–
Hiphos (L) 10000 (Liquid)	0.01	–
Calculated Nutrients
DM (%)	88 (87.32)	88 (88)
CP (%)	23 (22.50)	22 (22.50)
ME	12MJ/kgDM	12.5MJ/kgDM
Crude fat (%)	3.60	(5.02)
Fibre (%)	4.63	(2.78)
Ash (%)	5 (4.49)	5 (4.74)
Lysine (%)	1.32	1.32
Methionine (%)	0.49	0.65
Methionine + Cystine	0.95	0.87
Threonine (%)	0.86	0.77
Isoleucine (%)	0.86	0.78
Valine (%)	0.96	0.86
Arginine (%)	1.37	1.23
Tryptophan (%)	0.20	0.18
Leucine (%)	1.41	1.27
Sodium (%)	0.14	(0.13)
Available phosphorus (%)	0.62	(0.44)
Calcium (%)	0.81	(0.64)

¹Premix per kg of the diet: Vitamins; A: 8000IU; D3: 5000IU; E:0.075 g; Trace elements; Calcium iodate:3.1 mg (iodine:2.0 mg); Copper sulphate: 80 mg (copper 3b405:27 mg); Iron sulphate: 83.5 mg (Iron 3b103); Zootechnical additives; Axtra PHY 10 000 L: 0.01%; Ronozyme cereal WX-MG MP E1607 in cat N of directive 70/524/EEC: 0.029%; Maxiban G160 (80 mg/kg Narasin and 80 mg/kg Nicarbazin to provide 50 mg/kg Narasin and 50 mg/kg Nicarbazin in final feed as an aid in the prevention of coccidiosis in broiler chickens).

Figure 1. Particle size distribution of maize included in the diets.

Table 2. Effect of typical and low protein diets with fine, coarse, and whole maize on growth performance from day 1 to 21.

Parameter	Treatment^1				SEM^2	P-value
	CON	M350	M2600	WM
Initial body weight (g)	40.04	40.11	40.22	40.12	0.265	0.971
Final body weight (g)	1004^a	665.9^c	768.0^b	959.4^a	22.14	<0.001
Body weight gain (g)	964.1^a	625.8^c	727.8^b	919.3^a	22.06	<0.001
Feed intake (g)	1223^a	914.6^c	1054^bc	1165^ab	49.33	0.002
Feed conversion ratio (g/g)	1.273	1.471	1.462	1.262	0.072	0.087

¹CON: Commercial diet, crude protein 22.50%, M350: CON + 20% maize of GMD 350 µm crude protein 19.90%, M2600: CON + 20% maize of GMD 2600 µm crude protein 19.90%, WM: CON + 20% whole maize crude protein 19.90%.

²SEM: Standard error of means.

^a,b,cMeans within a row with different superscripts differ significantly (p ≤ 0.05).

Table 3. Effect of typical and low protein diets with fine, coarse, and whole maize on gastrointestinal tract organs.

Parameter	Treatment^1				SEM^2	P-value
	CON	M350	M2600	WM
Absolute weights (g)
D14 Proventriculus	2.794^a	2.245^b	2.290^b	2.393^ab	0.138	0.044
D14 Gizzard	11.15^ab	9.649^c	9.900^bc	11.57^a	0.488	0.031
D14 Small intestine	19.85^a	14.65^c	16.37^bc	17.92^ab	0.915	0.006
D14 Gizzard: proventriculus (g/g)	4.055^b	4.322^b	4.315^b	4.866^a	0.166	0.020
D21 Proventriculus	4.407	4.429	4.202	4.642	0.200	0.505
D21 Gizzard	18.40	18.87	18.64	18.96	1.079	0.983
D21 Small intestine	26.91	28.09	24.83	24.65	1.174	0.148
D21 Gizzard: proventriculus (g/g)	4.169	4.226	4.454	4.165	0.189	0.675
Relative weights (g/kg BW)
D14 Proventriculus	6.049^b	7.225^a	6.990^a	5.950^b	0.253	0.003
D14 Gizzard	24.31^b	31.15^a	30.07^a	29.00^a	1.191	0.004
D14 Small intestine	43.26^b	47.22^ab	50.44^a	44.54^b	1.741	0.043
D21 Proventriculus	4.580	4.962	4.962	4.845	0.206	0.527
D21 Gizzard	19.04	21.06	21.95	19.86	1.146	0.318
D21 Small intestine	27.78^bc	31.26^a	29.01^ab	25.78^c	1.037	0.012
Measurements
D14 Gastric isthmus diameter (mm)	7.020^a	6.450^a	5.650^b	5.695^b	0.232	0.001
D14 Small intestine (cm)	135.8	121.4	125.2	126.5	5.380	0.313
D21 Gastric isthmus diameter (mm)	7.515^a	7.401^a	6.466^b	6.380^b	0.203	0.001
D21 Small intestine (cm)	152.8	153.7	152.1	152.0	3.674	0.987
Intestinal density (g/100 cm)
D14 Small Intestine	14.56^a	12.09^c	13.18^bc	14.19^ab	0.465	0.006
D21 Small Intestine	17.62^ab	18.20^a	16.26^b	16.15^b	0.567	0.049

¹CON: Commercial diet, crude protein 22.50%, M350: CON + 20% maize of GMD 350 µm crude protein 19.90%, M2600: CON + 20% maize of GMD 2600 µm crude protein 19.90%, WM: CON + 20% whole maize crude protein 19.90%.

²SEM: Standard error of means.

^a,b,cMeans within a row with different superscripts differ significantly (p ≤ 0.05).

BW: Body weight.

Small intestine consists of duodenum, jejunum and ileum.

Table 4. Effect of typical and low-protein diets with fine, coarse, and whole maize on gizzard histology and ileum histology (µm), tensile strength (N), and gizzard digesta particle size (µm).

Parameter	Treatment^1				SEM^2	P-value
	CON	M350	M2600	WM
Gizzard histology (µm)
D14 Koilin	373.1^b	335.5^b	440.7^a	327.8^b	21.48	0.006
D14 Mucosa of lamina propria	538.4^a	359.3^b	442.2^ab	384.9^b	36.70	0.014
D14 Submucosa	181.8^a	118.4^bc	164.6^ab	107.2^c	17.84	0.023
D14 The extent of tunica muscularis	1093^a	813.1^b	1048^a	820.0^b	66.65	0.011
D21 Koilin	401.6	494.8	416.7	371.3	31.52	0.070
D21 Mucosa of lamina propria	528.8^ab	551.5^a	400.8^c	423.9^bc	40.60	0.040
D21 Submucosa	177.6	176.5	110.4	123.1	23.28	0.113
D21 The extent of tunica muscularis	1108^ab	1223^a	927.9^b	918.3^b	75.85	0.029
Ileum histology (µm)
D14 Villus height	545.8	561.8	517.9	570.4	38.71	0.785
D14 Crypt depth	151.5	136.3	143.1	140.4	10.21	0.757
D14 Mucosal depth	186.3^a	150.2^b	135.4^b	166.2^ab	11.80	0.039
D14 Villus: crypt	3.693	4.356	3.725	4.101	0.327	0.439
D21 Villus height	697.2	614.3	656.0	631.8	22.87	0.095
D21 Crypt depth	123.0	140.1	136.6	147.3	8.155	0.231
D21 Mucosal depth	287.4	262.2	254.0	301.2	25.10	0.530
D21 Villus: crypt	5.799^a	4.461^b	4.834^ab	4.396^b	0.329	0.027
Tensile strength (N)
D14 Gizzard	9.789	8.609	8.931	9.563	1.804	0.963
D14 Ileum	1.294	1.077	1.184	1.468	0.168	0.418
D21 Gizzard	14.01	9.485	11.94	15.11	2.207	0.318
D21 Ileum	1.433	1.559	1.611	1.680	0.168	0.763
Gizzard digesta particle size
D14 GMD (µm)	1572^a	1375^b	1583^a	1678^a	62.24	0.021
D21 GMD (µm)	1640	1685	1773	1745	49.33	0.259

¹CON: Commercial diet, crude protein 22.50%, M350: CON + 20% maize of GMD 350 µm crude protein 19.90%, M2600: CON + 20% maize of GMD 2600 µm crude protein 19.90%, WM: CON + 20% whole maize crude protein 19.90%.

²SEM: Standard error of means.

^a,b,cMeans within a row with different superscripts differ significantly (p ≤ 0.05).

The extent of tunica muscularis: Koilin+ Mucosa of lamina propria+ Submucosa.

Table 5. Effect of typical and low-protein diets with fine, coarse, and whole maize on nitrogen excretion and efficiency (D0–21), and welfare variables.

Parameter	Treatment^1				SEM^2	P-value
	CON	M350	M2600	WM
N excretion (g/bird)	16.08^a	10.97^b	12.45^ab	10.42^b	1.650	0.026
N Efficiency (%)	63.91^ab	62.91^b	63.60^b	72.59^a	3.022	0.036
Excreta and litter characteristics, and footpad scores
D20 Litter N (%)	2.931	2.470	2.501	2.641	0.125	0.068
D20 Litter moisture (%)	15.40^a	8.174^b	8.374^b	9.335^b	1.566	0.013
D21 Footpad scores	0.357^a	0.143^b	0.071^b	0.001^b	0.070	0.013

¹CON: Commercial diet, crude protein 22.50%, M350: CON + 20% maize of GMD 350 µm crude protein 19.90%, M2600: CON + 20% maize of GMD 2600 µm crude protein 19.90%, WM: CON + 20% whole maize crude protein 19.90%.

²SEM: Standard error of means.

^a,b,cMeans within a row with different superscripts differ significantly (p ≤ 0.05).