Effects of different methionine to lysine ratios in starter feed on growth, blood, digestive traits, and carcass traits in goat kids

Figures & data

Table 1. Ingredients in the treatment starter.

Ingredients (% fresh basis)	A^1	B^1	C^1
Corn grain	64	64	64
Wheat bran	4	4	4
Molasses, cane	4	4	4
Soybeans, full-fat	19.2	19.2	19.2
Soybean meal	2	2	2
S + M+F^2	2.5	2.5	2.5
Dicalcium phosphate	0.5	0.5	0.5
Calcium carbonate	2.0	2.0	2.0
Salt	0.5	0.5	0.5
Mineral and vitamin premix	1.1	1.1	1.1
Antioxidants	0.2	0.2	0.2
Synthetic lysine^3	0. 115	0.053	0
Chemical composition (NRC)
Crude protein^4	17	17	17
Metabolizable energy (Kcal/kg)	3037.18	3037.18	3037.18
Calcium^4	1.006	1.006	1.006
Phosphorus^4	0.523	0.523	0.523
Lysine^4	0.885	0.823	0.770
Methionine^4	0.257	0.257	0.257
Met/Lys ratio	0.29	0.31	0.33

¹ Starter groups (Met-to-Lys ratios): A (0.29), B (0.31), and C (0.33).

² Probiotic fermentation product.

³ L-lysine crystalline powder, CJ Corporation.

⁴ % on dry matter basis.

Table 2. Effects of methionine-to-lysine ratio in the starter on growth performance of goat kids¹.

	A	B	C	P-value
Initial BW^2 (kg)	8.09 ± 0.57	8.19 ± 0.60	8.45 ± 0.57	0.90
Final BW (kg)	15.24 ± 0.59	14.48 ± 0.61	15.60 ± 0.59	0.41
ADG (g/d)	178.3 ± 9.0	169.2 ± 9.1	199.6 ± 9.4	0.06
Feed intake (g/d)	245.7 ± 22.1	228.0 ± 22.7	273.0 ± 22.1	0.36
FCR	1.57 ± 0.19	1.48 ± 0.20	1.56 ± 0.19	0.94

¹ Values represent mean ± standard deviation.

² BW: body weight; ADG: average daily weight; FCR: feed conversion ratio.

Table 3. Effects of methionine-to-lysine ratio in the starter on blood parameters¹ of goat kids.

	A	B	C	P-value^2
Glu^3 (mg/dL)	69.64 ± 1.26	70.57 ± 1.30	71.42 ± 1.26	0.61
γ-GT (U/L)	54.20 ± 2.94	55.40 ± 3.04	60.56 ± 2.94	0.28
TP (g/dL)	06.39 ± 0.12	06.26 ± 0.12	06.48 ± 0.12	0.44
Alb (g/dL)	03.50 ± 0.06^a	03.33 ± 0.06^b	03.58 ± 0.06^a	0.02
Glo (g/dL)	02.89 ± 0.13	02.93 ± 0.14	02.90 ± 0.13	0.97
A/G	01.26 ± 0.05	01.15 ± 0.05	01.27 ± 0.05	0.28
BUN (mg/dL)	15.72 ± 0.76	17.16 ± 0.79	16.66 ± 0.76	0.42

¹ Values represent mean ± standard deviation.

^{2a, b} Values in rows with different letters are significantly different (P < 0.05).

³ Glu: glucose; γ-GT: γ-glutamyl transferase; TP: total protein; Alb: albumin; Glo: globulin; A/G: albumin: globulin; BUN: blood urine nitrogen.

Table 4. Effects of methionine-to-lysine ratio in the starter on digestive traits of goat kids¹.

	Treatment^2			P-value
	A	B	C	Trt^3	L^3	Q^3
Intake (g/d)
Milk replacer
Dry matter	96.9	96.9	96.9	–	–	–
Crude protein	24.5	24.5	24.5	–	–	–
Starter
Dry matter	197.6 ± 49.8	141.2 ± 71.4	165.0 ± 46.3	0.63	0.59	0.45
Crude protein	030.3 ± 7.6	022.4 ± 11.3	025.2 ± 7.1	0.68	0.59	0.51
Apparent digestibility (%) (Milk replacer digestibility of 80%)
Dry matter	86.5 ± 2.8	83.4 ± 2.8	86.4 ± 4.2	0.61	0.97	0.34
Crude protein	77.6 ± 5.0	72.1 ± 5.1	79.9 ± 6.1	0.40	0.68	0.21

¹ N = 8 goat kids per group.

² Values represent mean ± standard deviation.

³ Trt = the effect of treatment; L = Linear relationship; Q = Quadratic relationship.

Table 5. Effects of methionine to lysine ratio in the starter on carcass traits of MLRs goat kids¹.

Item	Treatment^2			P-value
	A	B	C	Trt^3	L^3	Q^3
Fasted live weight (kg)	16.73 ± 0.49^b	16.10 ± 0.67^b	18.30 ± 0.47^a	0.02	0.03	0.02
Carcass weight (kg)	07.78 ± 0.29^ab	07.25 ± 0.51^b	08.63 ± 0.19^a	0.02	0.06	0.02
Dressing percentage (%)	46.50 ± 0.80	45.02 ± 1.84	47.15 ± 0.89	0.30	0.62	0.15
Total guts weight (kg)	04.16 ± 0.71	04.24 ± 0.47	04.71 ± 0.31	0.56	0.33	0.68
Offal percentage (%)	24.90 ± 4.10	26.50 ± 3.70	25.70 ± 1.10	0.88	0.80	0.69
Skin weight (kg)	01.39 ± 0.02	01.27 ± 0.08	01.60 ± 0.18	0.07	0.12	0.06
Heart weight (g)	77.70 ± 4.50^ab	69.30 ± 5.70^b	88.30 ± 4.60^a	0.02	0.08	0.02
Hepatobiliary weight (kg)	00.30 ± 0.02	00.34 ± 0.03	00.35 ± 0.04	0.24	0.12	0.55
Lung weight (kg)	0.174 ± 0.009	0.176 ± 0.004	0.202 ± 0.014	0.06	0.03	0.21
Kidney weight (g)	60.30 ± 1.70	65.70 ± 3.30	76.00 ± 10.40	0.12	0.05	0.67
Spleen weight (g)	35.00 ± 7.50	28.70 ± 4.10	31.70 ± 4.50	0.56	0.57	0.37
Stomach weight (kg)	00.97 ± 0.61	00.39 ± 0.03	00.41 ± 0.07	0.26	0.17	0.38
Reticulorumen weight (kg)	00.73 ± 0.45	00.29 ± 0.02	00.40 ± 0.08	0.30	0.25	0.29
Abdominal fat weight (kg)	00.47 ± 0.08	00.43 ± 0.20	00.59 ± 0.08	0.50	0.41	0.41
Intestinal weight (kg)	00.49 ± 0.04	00.47 ± 0.05	00.55 ± 0.09	0.50	0.38	0.45
Intestinal length (m)	13.85 ± 4.25	15.45 ± 1.80	15.11 ± 1.24	0.83	0.66	0.70

¹ N = 5 goat kids per group.

² Values represent mean ± standard deviation.

³ Trt = the effect of treatment; L = Linear relationship; Q = Quadratic relationship.

^{4 a, b} Values in rows with different letters are significantly different (P < 0.05).

Data availability statement

The data that support the findings of this study are available on request from the corresponding author, C. P. Wu. The data are not publicly available because they contain information that could compromise the privacy of research participants.