Improved performance and small intestinal development of broiler chickens by dietary L-glutamine supplementation

Figures & data

Table 1. Feed ingredients and chemical composition of the starter (day 0–21) and grower (day 21–42) diets (g/kg as fed).

	Starter diets (day 0–21)
	Dietary glutamine supplementation (%)
Ingredients	0	0.5	1.0	1.5	Grower diet (day 21–42)
Corn	545.0	556.0	565.8	577.8	612.9
Soya bean meal	355.0	343.2	330.5	319.0	303.8
Soya bean oil	42.0	42.0	42.0	42.0	45.0
Common salt	3.0	3.0	3.0	3.0	2.7
Dicalcium phosphate	17.3	17.4	18.9	18.2	16.3
Limestone	13.4	13.4	14.0	13.7	10.6
Bicarbonate sodium	1.0	1.0	1.0	1.0	1.0
DL-Methionine	3.0	3.1	3.2	3.3	2.4
L-Lysine	0.5	1.0	1.3	1.7	0.2
L-Threonine	–	–	0.2	0.3	–
Vit + Min premix^a	5.0	5.0	5.0	5.0	5.0
Sand	15	10	5	–	–
L-Glutamine	–	5	10	15	–
Calculated nutrients
ME (kcal /kg)	3050	3050	3050	3050	3157
Crude Protein (%)	21.85	21.85	21.85	21.85	19.73
Calcium (%)	0.99	0.99	1.04	1.01	0.85
Available P (%)	0.45	0.45	0.47	0.46	0.42
Sodium (%)	0.16	0.16	0.16	0.16	0.15
Lysine (%)	1.20	1.20	1.20	1.20	1.05
Met + Cys (%)	0.95	0.95	0.95	0.95	0.85
Threonine (%)	0.82	0.80	0.80	0.80	0.75
Glutamine (%)	3.21	3.63	4.04	4.47	2.91
^aTo provide vitamins and minerals per kilogram of diet: vitamin A, 11000 IU; vitamin D3,1800 IU; vitamin E, 36 mg; vitamin K3, 5 mg; vitamin B12, 1.6 mg; thiamine, 1.53 mg; riboflavin, 7.5 mg; niacin, 30 mg; pyridoxine, 1.53 mg; biotin, 0.03 mg; folic acid, 1 mg; pantothenic acid, 12.24 mg; Etoxycoin, 0.125 mg; Fe, 250 mg; Zn-sulfate, 84 mg; Mn-sulfate, 160 mg; iodine, 1.6 mg; Cu-sulfate, 20 mg; selenium, 0.2 mg; and cobalt, 0.4 mg.

Table 2. Effect of dietary glutamine supplementation on performance of broiler chickens.

	Average daily weight gain (g/bird)			Average daily feed intake (g/bird)			Feed conversion ratio (g/g)
	Period (day)			Period (day)			Period (day)
Dietary Gln inclusion (%)	0–21	21–42	0–42	0–21	21–42	0–42	0–21	21–42	0–42
0	27.26^b	72.73	50.00^b	48.39	144.01	96.20	1.79	2.00	1.93
0.5	28.20^b	73.60	50.90^ab	52.16	144.54	98.36	1.85	1.98	1.94
1.0	31.94^a	78.71	55.32^a	54.23	147.15	100.69	1.71	1.87	1.82
1.5	25.54^b	71.80	48.67^b	47.65	142.02	94.83	1.87	1.98	1.95
±SEM	1.148	3.157	1.607	1.817	1.923	1.415	0.091	0.086	0.059
P-value	0.013	0.445	0.050	0.075	0.348	0.058	0.589	0.700	0.412
Contrasts
Linear	0.7832	0.8722	0.9522	0.9856	0.7017	0.7852	0.8070	0.6494	0.8464
Quadratic	0.0077	0.2423	0.0369	0.0146	0.1663	0.0151	0.5689	0.4660	0.3414
^a,bValues in the same columns and variable with no common superscript differ significantly (P≤0.05)

Table 3. Effect of dietary glutamine supplementation on relative weight of each small intestinal section to live body weight (%) in broiler chickens.

	Duodenum	Jejunum	Ileum
Dietary Gln inclusion (%)		(%)
Day 21
0	1.067^b	2.080^b	2.076
0.5	1.205^ab	2.366^ab	2.162
1.0	1.416^a	2.924^a	2.856
1.5	1.465^a	3.107^a	2.603
±SEM	0.096	0.244	0.274
P-value	0.042	0.039	0.198
Contrasts
Linear	0.007	0.006	0.087
Quadratic	0.653	0.837	0.548
Day 42
0	0.607	1.133	0.994
0.5	0.615	1.345	1.242
1.0	0.667	1.369	1.076
1.5	0.732	1.400	1.186
±SEM	0.066	0.089	0.0802
P-value	0.541	0.193	0.183
Contrasts
Linear	0.176	0.061	0.277
Quadratic	0.680	0.329	0.407
^a,bValues in the same columns and variable with no common superscript differ significantly (P≤0.05).

Table 4. Effect of dietary glutamine supplementation on small intestinal morphology of broiler chickens at 21 days of age.

Dietary Gln inclusion (%)	Villus height	Villus width	Crypt depth	Muscular layer thickness	Villus height to crypt depth ratio	Average villus density	Villus surface area
	(µm)				(µm/µm)	(villi/mm^2)	(×10^−3, µm^2)
Duodenum
0	824.22^b	101.36^b	218.35	202.41	3.772	5.5	261.14^b
0.5	1076.50^ab	102.19^b	205.59	234.78	5.317	7	345.42^b
1.0	1187.15^a	132.82^a	192.46	295.72	6.164	7	495.87^a
1.5	1285.98^a	147.87^a	211.39	212.61	6.298	8	597.09^a
±SEM	88.597	4.083	21.835	29.517	0.8064	0.75	33.316
P-value	0.049	0.003	0.856	0.255	0.246	0.272	0.0061
Contrasts
Linear	0.019	0.0007	0.745	0.526	0.079	0.089	0.001
Quadratic	0.435	0.156	0.508	0.122	0.043	0.755	0.811
Jejunum
0	848.05^b	92.84^b	236.35	202.27	3.650	7	247.43^b
0.5	890.19^b	89.61^b	191.96	209.51	4.647	7	251.17^b
1.0	1123.77^a	132.26^a	209.27	247.30	5.432	7.5	465.13^a
1.5	1234.58^a	143.81^a	208.41	289.81	5.930	8.5	559.24^a
±SEM	51.821	7.017	20.479	39.343	0.4834	0.7906	35.917
P-value	0.016	0.011	0.552	0.463	0.098	0.555	0.0079
Contrasts
Linear	0.003	0.003	0.507	0.163	0.024	0.230	0.002
Quadratic	0.543	0.351	0.347	0.677	0.633	0.561	0.276
Note: All measurements were done by 5x objective lens.
^a,bValues in the same columns and variable with no common superscript differ significantly (P≤0.05).

Table 5. Effect of dietary glutamine supplementation on small intestinal morphology of broiler chickens at 42 days of age.

Dietary Gln inclusion (%)	Villus height	Villus width	Crypt depth	Muscular layer thickness	Villus height to crypt depth ratio	Average villus density	Villus surface area
	(µm)				(µm/µm)	(villi/mm^2)	(×10^−3, µm^2)
Duodenum
0	1354.16^b	145.33	253.58	262.34^c	5.34	5.5	609.63^c
0.5	1437.19^b	146.80	246.57	325.32^ab	5.97	5.5	660.98^bc
1.0	1754.35^a	166.48	202.36	310.83^b	8.78	6	916.71^ab
1.5	1797.97^a	189.28	220.44	351.64^a	8.17	5.5	1069.33^a
±SEM	46.913	19.546	25.355	8.870	0.7158	0.4330	70.008
P-value	0.006	0.443	0.525	0.009	0.068	0.803	0.026
Contrasts
Linear	0.001	0.158	0.274	0.003	0.024	0.481	0.006
Quadratic	0.696	0.614	0.646	0.279	0.434	0.594	0.509
Jejunum
0	929.90^b	124.21	241.60	219.04^b	3.941	6.5	361.82^b
0.5	1098.80^ab	143.51	241.23	297.38^a	4.553	7	496.60^ab
1.0	1238.48^a	157.77	202.32	237.54^b	6.121	7	614.44^a
1.5	1267.66^a	165.01	212.77	306.63^a	5.993	7.5	657.25^a
±SEM	53.648	8.161	16.566	12.543	0.4639	0.6123	45.306
P-value	0.034	0.080	0.351	0.018	0.068	0.734	0.0325
Contrasts
Linear	0.008	0.020	0.165	0.022	0.020	0.335	0.007
Quadratic	0.262	0.500	0.760	0.731	0.469	1.000	0.367
Note: All measurements were done by 5x objective lens.
^a,b,cValues in the same columns and variable with no common superscript differ significantly (P≤0.05).