Effects of chitooligosaccharide supplementation on laying performance, egg quality, blood biochemistry, antioxidant capacity and immunity of laying hens during the late laying period

Figures & data

Table 1. Composition and nutrient levels of the basal diet (air-dry basis).

Ingredients, %	Control diet
Corn	63.20
Soybean meal	23.30
Wheat bran	1.50
Limestone	9.30
Soybean oil	0.30
DL-Methionine	0.10
CaHPO4	0.80
Premix^a	1.50
Calculated nutritional level, %
CP	15.57
ME, MJ/Kg	11.03
Calcium	3.42
Total phosphorus	0.33
Methionine	0.35
Lysine	0.78

^aPremix provided the following per kilogram of diet: retinyl palmitate, 3.96 mg; VD₃, 0.06 mg; VE, 36 mg; VB₁₂, 0.012 mg; NaCl, 3 g; menadione sodium bisulphite, 4 mg; riboflavin, 5.6 mg; thiamine mononitrate, 2 mg; niacin, 30 mg; pantothenic acid, 10 mg; folic acid, 0.5 mg; biotin, 0.22 mg; Mn, 80 mg; Zn, 60 mg; Fe, 80 mg; Cu, 10 mg; I,0.55 mg; Se, 0.12 mg; choline, 250 mg.

Table 2. Effects of chitooligosaccharide on laying performance in laying hens^c.

Item	COS supplementation, mg/kg			SEM	p Value
	0	75	125
Feed intake, g/hen/day	93.47	94.54	94.15	0.35	.059
Hen-day e.g. g production, %	67.83^b	70.39^a	70.88^a	0.63	.006
Egg weight, g	52.91	53.54	53.87	0.40	.124
Egg mass, g/hen/day	35.89^b	37.69^a	38.18^a	0.49	.008
FCR	2.60^a	2.51^b	2.47^b	0.03	.005

COS: chitooligosaccharide; FCR: feed conversion ratio.

^a,bMeans sharing different letters in the same row are significantly different (p < .05).

^cData are means of five replications with 200 hens per replicate.

Table 3. Effects of chitooligosaccharide on egg quality in laying hens^c.

Item	COS supplementation, mg/kg			SEM	p Value
	0	75	125
Albumen height, mm	5.25	5.51	4.99	0.37	.376
Haugh units	72.69	74.60	69.66	3.00	.259
Yolk colour, points	11.21^a	11.75^a	9.88^b	0.25	.000
Eggshell strength, Kgf	4.01^b	4.19^a,b	4.42^a	0.15	.021
Eggshell thickness, mm	0.35^b	0.37^a	0.37^a	0.01	.015

COS: chitooligosaccharide; Kgf: kilogram force.

^a,bMeans sharing different letters in the same row are significantly different (p < .05).

^cn = 30 eggs per group.

Table 4. Effects of chitooligosaccharide on serum biochemical indices in laying hens^c.

Item	COS supplementation, mg/kg			SEM	p Value
	0	75	125
Ca, mmol/L	4.83	5.03	5.13	0.27	.777
P, mmol/L	1.52	1.40	1.58	0.13	.430
ALP, King Unit/100 mL	15.80	17.00	17.70	0.73	.074
LDH, U/L × 10^3	8.58	9.08	9.33	0.61	.486
TP, g/L	34.83	35.13	35.88	1.06	.607
ALB, g/L	18.25^b	19.92^a,b	23.10^a	1.44	.024
CG, g/L	16.58	15.21	12.78	1.68	.128
AST, IU/L	49.47	48.48	49.05	1.84	.865
ALT, IU/L	15.51	15.62	16.24	0.65	.506
Glucose, mmol/L	9.55	10.20	10.63	0.87	.490

ALB: albumin; ALP: alkaline phosphatase; ALT: glutamic-pyruvic transaminase; AST: glutamic-oxalacetic transaminase; ALB: albumin; COS: chitooligosaccharide; LDH: lactic dehydrogenase; TP: total proteinx.

^a,bMeans sharing different letters in the same row are significantly different (p < .05).

^cn = 10 hens per group.

Table 5. Effects of chitooligosaccharide on contents of serum lipids in laying hens^c.

Item	COS supplementation, mg/kg			SEM	p Value
	0	75	125
CHO, mmol/L	2.10^a	1.80^a,b	1.60^b	0.12	.014
LDL-C, mmol/L	0.22	0.20	0.22	0.01	.228
HDL-C, mmol/L	0.20	0.19	0.18	0.01	.304
TG, mmol/L	18.01^a	14.22^b	12.12^b	0.72	.001

COS: chitooligosaccharide; CHO: cholesterol; HDL-C: high density lipoprotein cholesterol; LDL-C: low density lipoprotein cholesterol; TG: triglycerides.

^a,bMeans sharing different letters in the same row are significantly different (p < .05).

^cn = 10 hens per group.

Table 6. Effects of chitooligosaccharide on serum antioxidant capacity in laying hens^c.

Item	COS supplementation, mg/kg			SEM	p Value
	0	75	125
T-AOC, U/mL	7.53^c	8.87^b	10.30^a	0.42	.002
T-SOD, U/mL	131.34	133.67	141.22	6.43	.312
CuZn-SOD, U/mL	114.17	114.69	117.93	3.21	.490
GSH, mg/L	11.63	11.27	12.02	0.69	.588
GSH-Px, U/mL	1432.21	1503.26	1560.67	53.19	.130
CAT, U/mL	13.00	13.21	14.30	0.72	.183
MDA, nmol/mL	7.60^a	6.63^b	5.17^b	0.41	.003

COS: chitooligosaccharide; CuZn-SOD: CuZn-superoxide dismutase; CAT: catalase; GSH: glutathione; GSH-Px: glutathione peroxidase; MDA: malondialdehyde; T-AOC: total antioxidative capacity; T-SOD: total superoxide dismutase.

^a,bMeans sharing different letters in the same row are significantly different (p < .05).

^cn = 10 hens per group.

Table 7. Effects of chitooligosaccharide on immune ability in laying hens^c.

Item	COS supplementation, mg/kg			SEM	p Value
	0	75	125
IgA, ng/L	41.36	53.34	41.27	5.16	.283
IgG, ng/L	70.22	79.33	80.94	7.15	.363
IgM, μg/mL	2.67	3.04	2.97	0.39	.625
C3, μg/L	173.67^b	235.33^a	239.00^a	19.85	.040
C4, μg/L	96.34	110.50	104.67	11.07	.479

COS: chitooligosaccharide; C: complement; Ig: Immune gloulin.

^a,bMeans sharing different letters in the same row are significantly different (p < .05).

^cn = 10 hens per group.