Supplementation of thymol powder or green tea extract along with linseed in pig diet increases oxidative stability in blood and pork

Figures & data

Table 1. The ingredient and nutrient composition of experimental diets (as-fed basis).

Item	Grower diets^a (week 0 to 4)				Finisher diets^a (week 5 to 9)
	T1	T2	T3	T4	T1	T2	T3	T4
Ingredients, %
Corn	14.19	10.10	10.05	10.05	25.77	21.71	21.66	21.66
Wheat	15.00	15.00	15.00	15.00	10.00	10.00	10.00	10.00
Barley	5.00	5.00	5.00	5.00	–	–	–	–
Cassava	20.00	20.00	20.00	20.00	20.00	20.00	20.00	20.00
Rice bran fine	15.00	15.00	15.00	15.00	15.00	10.00	10.00	10.00
Rice bran solvent	–	–	–	–	9.00	15.00	15.00	15.00
Soybean hull	–	–	–	–	5.00	5.00	5.00	5.00
Distillers dried grains (DDGS)	8.00	8.00	8.00	8.00	–	–	–	–
Canola meal	6.60	8.00	8.00	8.00	–	–	–	–
Soybean meal	6.30	4.05	4.05	4.05	10.10	7.10	7.10	7.10
Palm kernel meal	5.00	5.00	5.00	5.00	–	–	–	–
Animal protein	2.00	2.00	2.00	2.00	–	–	–	–
Molasses	1.00	1.00	1.00	1.00	2.00	2.00	2.00	2.00
Wheat bran	–	2.28	2.28	2.28	–	–	–	–
Extruded linseed	–	2.50	2.50	2.50	–	5.00	5.00	5.00
Thymol powder	–	–	0.05	–	–	–	0.05	–
Green tea extract powder	–	–	–	0.05	–	–	–	0.05
Limestone	0.70	0.69	0.69	0.69	1.21	1.17	1.17	1.17
Sodium chloride	0.31	0.39	0.39	0.39	0.38	0.45	0.45	0.45
Monocalcium phosphate	0.03	–	–	–	0.54	0.57	0.57	0.57
Vitamin and mineral premix^b	1.00	1.00	1.00	1.00	1.00	1.00	1.00	1.00
Nutrient composition
Calculated ME, kcal/kg	3300	3300	3300	3300	3300	3300	3300	3300
Analysed, %
Dry matter	89.05	89.80	89.30	89.70	89.35	89.25	89.65	89.80
Crude protein	16.30	16.50	16.50	16.45	13.05	12.70	12.75	12.75
Crude fat	4.98	5.87	5.77	5.82	4.18	5.31	5.40	5.22
Crude fibre	5.02	5.31	5.47	5.44	5.70	6.25	6.44	6.43
Calcium	0.66	0.67	0.68	0.68	0.70	0.71	0.72	0.72
Total phosphorus	0.67	0.68	0.67	0.67	0.72	0.73	0.75	0.74
Lysine	1.04	1.05	1.03	1.05	0.88	0.89	0.90	0.89
Methionine	0.32	0.33	0.32	0.32	0.27	0.26	0.27	0.27
Methionine + cysteine	0.65	0.67	0.64	0.63	0.53	0.53	0.54	0.53
Threonine	0.66	0.68	0.67	0.67	0.54	0.56	0.57	0.56
Tryptophan	0.19	0.19	0.19	0.19	0.15	0.15	0.15	0.15

Note: ME: metabolisable energy.

^aT1 = control diet; T2 = control diet supplemented with extruded linseed; T3 = T2 diet supplemented with thymol powder; T4 = T2 diet supplemented with green tea extract.

^bVitamin and mineral premix provided the following per kilogram of diet: 100 mg Fe; 90 mg Cu; 60 mg Mn; 0.35 mg I; 0.25 mg Se; 80 mg Zn; 6000 IU vitamin A; 1400 IU vitamin D₃; 17 IU vitamin E; 2.5 mg vitamin K (menadione); 2 mg vitamin B₁; 8 mg vitamin B₂; 0.05 mg vitamin B₁₂; 0.15 mg biotin; 35 mg niacin; 18 mg pantothenic acid.

Table 2. The fatty acid composition of experimental diets.

Fatty acids (g/100g of total fatty acids)	Grower diets^a(week 0 to 4)				Finisher diets^a(week 5 to 9)
	T1	T2	T3	T4	T1	T2	T3	T4
C12:0	5.14	4.55	4.54	4.58	0.31	0.24	0.23	0.23
C14:0	2.02	1.82	1.81	1.82	0.56	0.47	0.46	0.45
C16:0	20.55	18.20	18.11	18.09	18.59	14.21	14.46	14.38
C16:1	0.85	0.76	0.75	0.75	0.60	0.50	0.51	0.50
C18:0	2.13	2.22	2.22	2.22	1.71	1.74	1.67	1.74
C18:1n-9	28.20	26.22	26.24	26.25	32.98	27.17	27.18	27.16
C18:2n-6	36.66	33.21	33.33	33.15	41.22	33.46	33.28	33.27
C18:3n-3	1.89	10.76	10.77	10.91	1.71	20.27	20.30	20.34
C20:0	0.96	0.86	0.83	0.85	0.87	0.72	0.72	0.73
C20:1n-9	0.76	0.67	0.67	0.68	0.75	0.62	0.63	0.62
C20:2	0.87	0.76	0.75	0.75	0.73	0.61	0.61	0.61
Total saturated fatty acids (SFA)	30.78	27.64	27.50	27.55	22.04	17.39	17.52	17.52
Total monounsaturated fatty acids (MUFA)	29.81	27.65	27.66	27.67	34.32	28.29	28.31	28.27
Total polyunsaturated fatty acids (PUFA)	39.42	44.72	44.84	44.80	43.65	54.33	54.18	54.22
PUFA/SFA	1.28	1.62	1.63	1.63	1.98	3.13	3.09	3.10
C18:2n-6/C18:3n-3	19.43	3.09	3.10	3.04	24.10	1.66	1.64	1.64

^aT1 = control diet; T2 = control diet supplemented with extruded linseed; T3 = T2 diet supplemented with thymol powder; T4 = T2 diet supplemented with green tea extract.

Table 3. The growth performance of growing-finishing pigs fed different diets.

Item	Dietary treatments^a				SEM	p Value
	T1	T2	T3	T4
Grower (week 0 to 4)
Initial weight, kg	50.34	50.35	50.37	50.34	1.158	1.000
Final weight, kg	77.82	77.15	77.96	77.48	1.478	.997
ADFI, g/d	2258	2196	2177	2223	42.29	.739
ADG, g/d	912	893	915	898	14.94	.872
FCR	2.475	2.461	2.381	2.471	0.019	.092
Finisher (week 5 to 9)
Initial weight, kg	77.82	77.15	77.96	77.48	1.478	.997
Final weight, kg	110.59	109.31	109.84	108.35	1.629	.947
ADFI, g/d	2768	2758	2718	2695	56.38	.475
ADG, g/d	931	919	911	881	14.43	.140
FCR	2.971	2.999	2.979	3.059	0.031	.485
Overall (week 0 to 9)
Initial weight, kg	50.34	50.35	50.37	50.34	1.158	1.000
Final weight, kg	110.59	109.31	109.84	108.35	1.629	.947
ADFI, g/d	2531	2499	2467	2476	47.43	.641
ADG, g/d	922	907	913	888	12.58	.208
FCR	2.741	2.753	2.699	2.782	0.021	.236

Note: SEM: standard error of the mean; ADFI: average daily feed intake; ADG: average daily gain; FCR: feed conversion ratio.

^aT1 = control diet; T2 = control diet supplemented with extruded linseed; T3 = T2 diet supplemented with thymol powder; T4 = T2 diet supplemented with green tea extract.

Table 4. The carcase quality of growing-finishing pigs fed different diets.

Item	Dietary treatments^a				SEM	p Value
	T1	T2	T3	T4
Slaughter weight, kg	112.33	111.83	111.67	111.17	1.224	.987
Hot carcase weight, kg	90.15	89.32	89.30	89.12	1.093	.985
Cold carcase weight, kg	87.62	87.07	87.07	86.52	1.098	.986
Dressing yield, %	77.98	77.83	77.97	77.78	0.281	.992
Carcase length, cm	82.67	82.33	82.33	82.00	0.491	.970
Loin eye area, cm^2	57.82	57.72	57.24	57.00	0.806	.976
Average backfat thickness, cm	2.72	2.71	2.61	2.64	0.065	.882

Note: SEM: standard error of the mean.

^aT1 = control diet; T2 = control diet supplemented with extruded linseed; T3 = T2 diet supplemented thymol powder; T4 = T2 diet supplemented with green tea extract.

Table 5. The blood lipid profile of growing-finishing pigs fed different diets.

Item, mg/dL	Dietary treatments^a				SEM	p Value
	T1	T2	T3	T4
Week 0
Triglyceride	60.17	60.33	58.17	59.50	2.184	.983
Total cholesterol	119.17	122.33	118.33	118.33	2.062	.877
HDL cholesterol	46.92	49.40	47.30	45.72	0.909	.483
LDL cholesterol	52.63	59.03	55.80	55.62	1.343	.336
Week 4
Triglyceride	60.33^b	53.50^c	53.17^c	52.83^c	1.260	.034
Total cholesterol	127.33^b	111.00^c	108.50^c	110.17^c	2.283	<.01
HDL cholesterol	46.75	45.47	43.97	43.45	1.011	.535
LDL cholesterol	58.72^b	47.67^c	46.17^c	46.77^c	1.542	<.01
Week 9
Triglyceride	57.67	50.33	49.17	49.67	2.572	.561
Total cholesterol	128.50^b	109.33^c	108.50^c	109.83^c	2.741	<.01
HDL cholesterol	47.10	45.28	43.77	44.72	1.657	.902
LDL cholesterol	58.73^b	46.73^c	45.63^c	47.18^c	1.713	<.01

Note: SEM: standard error of the mean.

^aT1 = control diet; T2 = control diet supplemented with extruded linseed; T3 = T2 diet supplemented with thymol powder; T4 = T2 diet supplemented with green tea extract.

^b,cMeans with different superscripts in the same row differ significantly (p < .05).

Table 6. The meat quality of longissimus thoracis et lumborum muscle of growing-finishing pigs fed different diets.

Item	Dietary treatments^a				SEM	p Value
	T1	T2	T3	T4
pH value
pH, 45 min post-mortem	6.44	6.39	6.54	6.38	0.034	.215
pH, 24 h post-mortem	5.71	5.68	5.73	5.64	0.024	.539
Colour
L* (lightness)	52.97	52.66	52.02	52.04	0.255	.366
a* (redness)	5.35	5.49	5.45	5.73	0.168	.865
b* (yellowness)	4.27	4.56	4.38	4.25	0.146	.856
Chemical composition, %
Moisture	73.30	73.18	73.22	73.09	0.072	.751
Crude protein	22.64	22.56	22.68	22.72	0.104	.955
Crude fat	2.17	2.22	2.15	2.12	0.074	.950
Water holding capacity, %
Drip loss	3.87	3.79	3.94	3.98	0.157	.973
Thawing loss	6.40	6.57	6.79	6.91	0.250	.879
Cooking loss	22.20	22.47	22.38	22.77	0.487	.980
Shear force, N/cm^2	38.29	37.42	37.26	37.46	1.336	.993

Note: SEM: standard error of the mean.

^aT1 = control diet; T2 = control diet supplemented with extruded linseed; T3 = T2 diet supplemented with thymol powder; T4 = T2 diet supplemented with green tea extract.

Figure 1. The blood oxidative stability of growing-finishing pigs fed different diets. MDA = malondialdehyde. T1 = control diet; T2 = control diet supplemented with extruded linseed; T3 = T2 diet supplemented with thymol powder; T4 = T2 diet supplemented with green tea extract. The data are presented as a mean with standard error of the mean. Bars with various letters within a time class are significant different (p < .01).

Figure 2. Influence of dietary treatment and storage time on the meat oxidative stability. MDA = malondialdehyde. T1 = control diet; T2 = control diet supplemented with extruded linseed; T3 = T2 diet supplemented with thymol powder; T4 = T2 diet supplemented with green tea extract. Interactive effect of dietary treatment (T1, T2, T3 and T4) and storage time (D0, D3 and D6) on the MDA levels measured in LTL muscle over refrigerated storage at 4 °C. The data are presented as a mean with standard error of the mean. Bars with various letters are significant different (p < .01).

Figure 3. The fatty acid composition of LTL muscle of growing-finishing pigs fed different diets. FA = fatty acid; SFA = total saturated fatty acids; MUFA = total monounsaturated fatty acids; PUFA = total polyunsaturated fatty acids. T1 = control diet; T2 = control diet supplemented with extruded linseed; T3 = T2 diet supplemented with thymol powder; T4 = T2 diet supplemented with green tea extract. The data is presented as a mean with standard error of the mean. Bars with various letters within a fatty acid type are significant different (p < .05).

Figure 4. The fatty acid composition of backfat of growing-finishing pigs fed different diets. FA = fatty acid; SFA = total saturated fatty acids; MUFA = total monounsaturated fatty acids; PUFA = total polyunsaturated fatty acids. T1 = control diet; T2 = control diet supplemented with extruded linseed; T3 = T2 diet supplemented with thymol powder; T4 = T2 diet supplemented with green tea extract. The data are presented as a mean with standard error of the mean. Bars with various letters within a fatty acid type are significant different (p < .05).

Figure 5. The PUFA/SFA and n-6/n-3 ratios of LTL muscle and backfat of growing-finishing pigs fed different diets. T1 = control diet; T2 = control diet supplemented with extruded linseed; T3 = T2 diet supplemented with thymol powder; T4 = T2 diet supplemented with green tea extract. The data is presented as a mean with standard error of the mean. Bars with various letters within a tissue type are significant different (p < .05).

Data availability statement

The data that support the findings of this study are available from the corresponding author upon reasonable request.