Gamma-amino butyric acid (GABA) supplementation alleviates dexamethasone treatment-induced oxidative stress and inflammation response in broiler chickens

Figures & data

Table 1. Diet chemical composition.

Ingredient (%)	Starter diet (1–21 d)	Grower diet (22–42 d)
Yellow corn	53.85	57.60
Corn gluten meal	6.9	6.0
Soybean oil meal	33.2	30.3
Soybean oil	2.0	2.0
DCP^a	1.8	1.8
Ground limestone^b	1.4	1.4
Mineral and vitamin premix^c	0.3	0.3
Salt	0.3	0.3
DL-methionine^d	0.1	0.1
Lysine^e	0.1	0.15
Choline chloride	0.05	0.05
Total	100	100
Diet chemical composition
Moisture (%)	9	9
Dry matter (%)	91	91
Crude protein (%)	22.9	21.8
ME (Kcal/kg)	3048	3081
Crude fat (%)	4.01	4.39
Crude fiber (%)	3.67	3.78
Ash (%)	6.23	5.59
Calcium (%)	0.98	0.97
Available phosphorus (%)	0.48	0.48
Lysine (%)	1.20	1.17
Methionine (%)	0.50	0.48

^aDCP: dicalcium phosphate (contain 18% Phosphorus and 21% calcium).

^bLimestone (contain 35% calcium).

^cMineral and vitamin premix produced by Heropharm and composed (per 3 kg) of vitamin A 1,20,00,000 IU, vitamin D 32,500,000 IU, vitamin E 10,000 mg, vitamin K3 2000 mg, vitamin B1 1000 mg, vitamin B2 5000 mg, vitamin B6 1500 mg, vitamin B₁₂10 mg, niacin 30,000 mg, biotin 50 mg, folic acid 1000 mg, pantothenic acid 10,000 mg, manganese 60,000 mg, zinc 50,000 mg, iron 30,000 mg, copper 4000 mg, iodine 300 mg, selenium 100 mg and cobalt 100 mg.

^deli-methionine (produced by Evonic Co. and contain 99% methionine).

^eLysine: lysine hydrochloride (contain 98% lysine).

1 g/kg of DEX premix. DEX premix: 0.01 g of dexamethasone (DEX) (Alfa Aesar (Tewksbury, MA) added to 9.9 g of ground corn. Dexamethasone premix was added at the expense of corn to supply 1 mg DEX/kg diet.

1, 2 g/kg of GABA premix. GABA premix: Prepared as 1 g of GABA (Tiancheng Biotechnology, Jinan, China) added to 9 g of ground corn. GABA premix was added at the expense of corn to supply 100, 200 mg GABA/kg diet.

Table 2. Growth performance and mortality of broiler chickens fed diets containing Gamma-amino butyric acid (GABA) concentration at 100 or 200 mg/kg with or without dexamethasone (DEX).

Treatments	BW (g)	FI (g)	FCR	Mortality
PC	3050^a	5429^a	1.78^b	0.03^b
NC	2287^c	4459^c	1.95^a	0.06^a
DG+	2700^b	4725^b	1.75^b	0.03^b
DG++	2730^b	4722^b	1.73^b	0.03^b
SEM	110	150	0.09	0.005
P-value	< 0.01	< 0.01	< 0.01	< 0.01

^a–dMeans with different superscripts in the same columns are significantly different (p < 0.05).

BW: Body weight; FI: Feed intake; FCR: Feed conversion ratio; PC; positive control (Without any treatment); NC: negative control (with 1 mg/kg DEX); DG+:1 mg/kg DEX and 100 mg/kg GABA; DG++: 1 mg/kg DEX and 200 mg/kg GABA.

Table 3. Serum and liver antioxidant function of broiler chickens fed diets containing Gamma-amino butyric acid (GABA) concentration at 100 or 200 mg/kg with or without dexamethasone (DEX).

Parameters		Treatments				SEM	p Value
		PC	NC	DG + DG	DG++DG
Serum	GPx (Mu/mL)	8326.1^a	1121.9^d	2019.42^c	2370.28^b	98.50	< 0.01
	SOD (U /mL)	364.90^b	270.25^c	380.93^b	405.79^a	29.50	< 0.01
	CAT (N mol/min/mL)	81.94^a	26.60^d	54.18^c	75.53^b	3.50	< 0.01
	MDA (n mol/ml)	11.57^c	14.85^a	12.70^b	12.24^b	0.98	< 0.01
Liver	GPx (U /mg protein)	19.01^a	14.00^b	17.25^a	18.50^a	2.10	< 0.01
	SOD (U/ mg protein)	750^a	630^b	751^a	770^a	15.1	< 0.01
	CAT (U /mg protein)	45.1^a	26.2^d	38.2^c	41.2^b	2.5	< 0.01
	MDA (nmol/mg protein)	0.34^bc	0.48^a	0.36^b	0.33^c	0.02	< 0.01

^{a, b, c}Mean values in the same row with different superscript letters were significantly different (p < 0.05).

PC: positive control (Without any treatment); NC: negative control (with 1 mg/kg DEX); DG+:1 mg/kg DEX and 100 mg/kg GABA; DG++: 1 mg/kg DEX and 200 mg/kg GABA; GPx: Glutathione peroxidase; SOD: Superoxide dismutase; CAT: Catalase; MDA: Malondialdehyde.

Table 4. Serum and liver cytokines of broiler chickens fed diets containing Gamma-amino butyric acid (GABA) concentration at 100 or 200 mg/kg with or without dexamethasone (DEX).

Parameters		Treatments				SEM	p Value
		PC	NC	DG+	DG++
Serum	IL-6 (ug/mL)	10.50^d	17.50^a	15.10^b	12.90^c	0.75	0.01>
	IL-8 (ug/mL)	11.20	10.50	10.30	10.20	1.90	0.15
	IL-10 (ug/mL)	12.12^d	25.50^a	20.25^b	17.21^c	1.95	0.01>
Liver	IL-6 (ug/mL)	0.46^d	1.60^a	0.92^b	0.75^c	0.03	0.01>
	IL-8(ug/mL)	1.20	1.35	1.50	1.30	0.75	0.08
	IL-10 (ug/mL)	1.30^d	3.60^a	2.61^b	2.15^c	0.05	0.01>

^{a, b, c}Mean values in the same row with different superscript letters were significantly different (P < 0.05).

PC: positive control (Without any treatment); NC: negative control (with 1 mg/kg DEX); DG+:1 mg/kg DEX and 100 mg/kg GABA; DG++: 1 mg/kg DEX and 200 mg/kg GABA.

IL-6, interleukin-6; IL-8, interleukin-8; IL-10, interleukin-10.

Table 5. Hematological parameters of broiler chickens fed diets containing Gamma-amino butyric acid (GABA) concentration at 100 or 200 mg/kg with or without dexamethasone (DEX).

Treatments	WBC (×10^3/µl)	RBC (×10^3/µl)	HGB (g/dl)	HCT (%)	Heterophile (/µl)	Lymphocyte (/µl)	Heterophile/ Lymphocyte
PC	181275.0	2.61	12.80	32.08	34060.5^b	141433^b	0.24^b
NC	183500.0	2.71	13.35	32.68	56749.5^a	119283^c	0.47^a
DG+	191325.0	2.73	14.60	35.13	26355.0^c	154190^a	0.17^c
DG++	186725.0	2.66	14.40	34.65	28151.5^c	158523^a	0.17^c
SEM	7044	0.82	2.70	2.54	4500	5142	0.02
p-value	0.53	0.49	0.14	0.54	0.00	0.00	0.00

^a–dMeans with different superscripts in the same columns are significantly different (p < 0.05).

PC: positive control (Without any treatment); NC: negative control (with 1 mg/kg DEX); DG+:1 mg/kg DEX and 100 mg/kg GABA; DG++: 1 mg/kg DEX and 200 mg/kg GABA; WBC: White blood cell; RBC: Red blood cell; HGB: Hemoglobin; HCT: Hematocrit.

Table 6. Activity of enzymes in serum of broiler chickens fed diets containing Gamma-amino butyric acid (GABA) concentration at 100 or 200 mg/kg with or without dexamethasone (DEX).

Treatments	ALT (U/L)	AST (U/L)	ALP (IU/l)
PC	10.37^d	148.80^d	359.34^c
NC	27.32^c	182.05^b	368.65^b
DG+	62.43^a	154.79^c	362.01^c
DG++	39.69^b	185.12^a	385.59^a
SEM	3.84	5.40	2.61
p-value	0.00	0.00	0.00

^a-dMeans with different superscripts in the same columns are significantly different (p < 0.05).

PC: positive control (Without any treatment); NC: negative control (with 1 mg/kg DEX); DG+:1 mg/kg DEX and 100 mg/kg GABA; DG++: 1 mg/kg DEX and 200 mg/kg GABA; ALT: Alanine transaminase; AST: Aspartate transaminase; ALP: alkaline phosphatase; GABA: gamma amino butyric.

Table 7. Serum lipid profile of broiler chickens fed diets containing Gamma-amino butyric acid (GABA) concentration at 100 or 200 mg/kg with or without dexamethasone (DEX).

Treatments	Cholesterol (mg/dl)	Triglyceride (mg/dl)	HDL (mg/dl)	LDL (mg/dl)
PC	180.80^d	182.37^d	97.35^a	31.34^d
NC	260.05^a	270.32^c	84.40^b	87.65^a
DG+	253.79^a	349.43^b	73.99^c	52.01^c
DG++	246.12^a	365.69^a	64.67^d	63.59^b
SEM	5.40	3.84	1.76	2.61
p-value	0.01	0.00	0.00	0.00

^a-dMeans with different superscripts in the same columns are significantly different (p < 0.05).

PC: positive control (Without any treatment); NC: negative control (with 1 mg/kg DEX); DG+:1 mg/kg DEX and 100 mg/kg GABA; DG++: 1 mg/kg DEX and 200 mg/kg GABA; HDL: High-density lipoprotein; LDL: Low-density lipoprotein.