Creatine or guanidinoacetic acid? Which is more effective at enhancing growth, tissue creatine stores, quality of meat, and genes controlling growth/myogenesis in Mulard ducks

Figures & data

Table 1. Ingredient composition and calculated nutrient content of basal diets.

Ingredient (%)	Starting diet (0–21)	Growing-overfeeding diet (22–42)
Corn	41.2	57.8
Soy bean meal (44%)	36.7	21.5
Wheat bran	8	9.7
Bakery byproduct	8.6	5.1
Soybean oil	2.3	2.6
Di-calcium phosphate	1.5	1.5
Ca carbonate	0.8	0.9
Na chloride	0.3	0.3
Premix^1	0.5	0.5
Methionine	0.1	0.1
Total	100	100
Calculated nutrient content
Crude protein (%)	22.10	16.57
Metabolizable energy (MJ/kg)	12.13	12.58
Ether extract (%)	2.49	2.96
Crude fibre (%)	3.30	3.27
Lysine (%)	1.28	0.87
Methionine (%)	0.43	0.37

Notes: Premix1 (per kg of diet): 10,000 IU; Vitamin A, 5000 IU; vitamin D3, 16 mg; vitamin E, 11 mg; vitamin K3, 2.5 mg; Vitamin B1, 2.3 mg; Vitamin B2, 7 mg; Vitamin B6: 4 mg; Vitamin B12: 14 mg; Folic acid:1.3 mg; Biotin:140 mg; Calcium pantotenate: 25 mg; Nicotinic acid: 65 mg; Fe: 75 mg; Cu:9 mg; Mn:65 mg; Zn: 40 mg; I: 0.32 mg; Se: 0.15 mg.

Table 2. Effect of CREA or (GAA) with or without methionine supplementation on Moulard duck’s performance (starter, grower and allover period).

	Control	CREA^2	GAA^3	GAAMet0.2^4	GAAMet0.4^5
Starter period (d 1–21)
BW, g/bird	1034^e ± 1.17	1191^b ± 0.66	1095^d ± 3.40	1173^c ± 0.71	1224^a ± 0.51
BWG, g/bird	974^e+ ± 1.17	1131^b ± 0.66	1035^d ± 3.40	1113^c ± 0.71	1164^a ± 0.51
FI, g/bird	1643.80^d ± 7.11	1798.40^a ± 4.18	1685.80^c ± 1.77	1787.00^a ± 3.16	1773.60^b ± 4.57
F: G ratio	1.69^a ± 0.01	1.59^d ± 0.00	1.63^b ± 0.00	1.61^c ± 0.00	1.52^e ± 0.00
Grower period (d 22–42)
BW, g/bird	2933^d ± 2.49	3196^b ± 3.73	3175^c ± 6.60	3192^b ± 3.54	3215^a ± 3.15
BWG, g/bird	1900^d ± 3.30	2005^b ± 3.22	2080^a ± 8.78	2019^b ± 4.08	1990^c ± 2.69
FI, g/bird	4349^ab ± 91.60	4320^ab ± 33.18	4493.80^a ± 59.32	4111^bc ± 50.78	3903^c ± 124.75
F: G ratio	2.29^a ± 0.05	2.16^b ± 0.02	2.16^b ± 0.03	2.04^c ± 0.03	1.96^c ± 0.06
Allover period
Final body weight, g/bird	2933^d ± 2.49	3196^b ± 3.73	3175^c ± 6.60	3192^b ± 3.54	3215^a ± 3.15
Feed intake, g/bird	5993^ab ± 92.71	6119^ab ± 34.50	6179^a ± 58.67	5898^bc ± 50.94	5677^c ± 122.26
Body weight gain, g/bird	2873^d ± 2.48	3136^b ± 3.73	3115^c ± 6.60	3132^b ± 3.54	3155^a ± 3.15
Feed: gain ratio	2.09^a ± 0.03	1.95^bc ± 0.01	1.98^b ± 0.02	1.88^c ± 0.02	1.80^d ± 0.04
Protein efficiency ratio	2.30^d ± 0.03	2.45^bc ± 0.01	2.42^c ± 0.02	2.54^b ± 0.02	2.66^a ± 0.05

^a.b.c.dValues with different superscripts within a row are significantly different (P < 0.05).

¹Values are means ± standard error, ²CREA = control diet plus 0.05% creatine, ³GAA = control diet plus 0.05%Guanidinoacetic acid, ⁴GAAMet0.2 = control diet plus 0.05% Guanidinoacetic acid with 0.2% methionine, ⁵GAAMet0.4 = control diet plus 0.05% Guanidinoacetic acid with 0.4% methionine.

Table 3. Effect of CREA or (GAA) with or without methionine supplementation on carcass characteristics and meat quality in Moulard ducks at slaughter (d 42).¹

	Control	CREA^2	GAA^3	GAAMet0.2^4	GAAMet0.4^5
Carcass traits
Carcass weight, g	2312^d ± 1.56	2568^b ± 3.60	2540^c ± 8.49	2567^b ± 3.73	2595^a ± 3.46
Carcass yield g/kg	1071^d ± 2.99	1331^b ± 3.61	1295^c ± 10.12	1330^b ± 3.87	1364^a ± 4.03
Breast weight, g	547.2^d ± 2.67	820.4^b ± 4.55	778.6^c ± 9.73	817.2^b ± 4.07	863.6^a ± 4.03
Breast meat yield g/kg	343.6^d ± 3.70	635.4^b ± 7.92	582.8^c ± 9.43	626^b ± 4.51	676.8^a ± 5.00
Carcass analysis
Moisture, %	76.32 ± 0.10	76.56 ± 0.12	76.60 ± 0.10	76.72 ± 0.09	76.80^c ± 0.05
Protein, %	20.90^bc ± 0.27	21.38^a ± 0.06	20.62^c ± 0.15	21.20^ab ± 0.05	21.46^a ± 0.05
FAT, %	1.80^a ± 0.05	1.74^ab ± 0.07	1.62 ^c ± 0.04	1.74^ab ± 0.05	1.62^c ± 0.05
Beast meat
pH, 0.5 h	6.30^c ± 0.01	6.35^b ± 0.02	6.38^b ± 0.01	6.36^b ± 0.01	6.44^a ± 0.01
pH, 24 h	5.74^c ± 0.02	5.80^ab ± 0.04	5.79^b ± 0.01	5.82^a ± 0.05	5.82^a ± 0.03
Drip loss, %	0.84 ± 0.04	0.82 ± 0.04	0.79 ± 0.05	0.79 ± 0.05	0.77 ± 0.08
Thaw loss, %	4.36 ± 0.35	4.16 ± 0.09	4.15 ± 0.15	4.18 ± 0.26	3.98 ± 0.31
Cooking loss, %	12.76 ± 0.37	12.78 ± 0.16	12.92 ± 0.21	13.20 ± 0.09	13.38 ± 0.17

^a.b.c.dValues with different superscripts within a row are significantly different (P < 0.05).

¹Values are means ± standard error, ²CREA = control diet plus 0.05% creatine, ³GAA = control diet plus 0.05%Guanidinoacetic acid, ⁴GAAMet0.2 = control diet plus 0.05% Guanidinoacetic acid with 0.2% methionine, ⁵GAAMet0.4 = control diet plus 0.05% Guanidinoacetic acid with 0.4% methionine.

Table 4. Plasma concentrations of CREA, GAA and homocyteine and Breast muscle concentrations of CREA and GAA of Moulard ducks at slaughter (d 42).

	Control	CREA^2	GAA^3	GAAMet0.2^4	GAAMet0.4^5
Creatine (mg/kg of FM^2)	4.40^d ± 0.07	5.08^c ± 0.07	6.32^b ± 0.06	6.20^bc ± 0.05	6.54^a ± 0.07
Guanidinoacetic acid (mg/kg of FM)	7. 9^a ± 0.08	4.56^bc ± 0.07	4.69^b ± 0.05	4.57^bc ± 0.09	4.4^c ± 0.07
Plasma creatine, μmol/L	95 ± 0.09^d	205 ± 0.08^a	150 ± 0.05^c	162 ± 0.07^b	160 ± 0.05^b
Plasma guanidinoacetic acid, μmol/L	7.1^c ± 0.03	7^c ± 0.02	35^a ± 0.17	32^b ± 0.15	30^b ± 0.14
Plasma Homocysteine, μmol/L	16.15^b ± 0.05	16.28^b ± 0.15	18.94^a ± 0.15	16.00^c ± 0.06	15.48^c ± 0.1

^a.b.c.dValues with different superscripts within a row are significantly different (P < 0.05).

¹Values are means ± standard error, ²CREA = control diet plus 0.05% creatine, ³GAA = control diet plus 0.05%Guanidinoacetic acid, ⁴GAAMet0.2 = control diet plus 0.05% Guanidinoacetic acid with 0.2% methionine, ⁵GAAMet0.4 = control diet plus 0.05% Guanidinoacetic acid with 0.4% methionine, ³FM = fresh matter.

Figure 1. Effect of CREA or GAA on the relative mRNA expression of (A) growth hormone, GH; (B) insulin-like growth factor-1, IGF-1; (C) mygenin and myostatin genes of Mulard ducks at slaughter (d 42).