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Table 2. Effects of dietary green tea by-products (GTB) on growth performances of finishing pigs.
Parameter
Control Antibiotic GTB-0.5%
Hossain et al. 2461
GTB-1.0% GTB-2.0%
Average initial weight (kg/pig) 77.20 ± 0.61 77.60 ± 0.69 77.47 ± 0.47 76.87 ± 0.71 77.07 ± 0.24
Average final weight (kg/pig) 113.33 ab ± 0.77 116.50 a ± 0.29 111.87 ab ± 2.07 112.80 ab ± 1.47 111.07 b ± 1.75
Average weight gain (kg/pig) 36.13 ab ± 1.37 38.90 a ± 0.98 34.40 ab ± 1.60 35.93 ab ± 1.29 34.00 b ± 1.51
Average feed intake (kg/pig) 131.67 b ± 8.82 47.50 ab ± 1.44 135.00 b ± 7.64 140.00 ab ± 7.69 158.20 a ± 0.92
Feed conversion ratio (feed/gain) 3.64 b ± 0.13 3.80 b ± 0.06 3.92 b ± 0.05 3.89 b ± 0.08 4.67 a ± 0.20
a,b Means with different superscripts within same row are significantly different (P < 0.05). Data are presented as the mean ± SE.
anti-mouse CD8 + monoclonal antibodies for cytotoxic (CD3 + ,
CD8 + ) T cells (Phar Mingen, San Diego, CA, USA) for 30 min at 4°C.
The lymphocytes were collected by centrifugation at 160 ×g for 5
min and rinsed three times with PBS containing 10% FBS. The
washed lymphocytes were fixed with 2% paraformaldehyde, and
approximately 1 × 10 4 cells were analyzed using a Coulter Epics XL
Flow Cytometer (Beckman Coulter, Inc. CA, USA).
Cytokines (IL-6 and TNF-α) analysis
Splenocytes (5 × 10 5 cells/ml) were cultured in 96-well flat-bottomed
tissue culture plates in a final volume of 200 µl per well containing
RPMI 1640 medium supplemented with 10% (v/v) fetal calf serum,
2 mM L-glutamine, 100 units/ml penicillin and 100 μg/ml
streptomycin, 1% (v/v) nonessential amino acids, and 0.05 mM 2mercaptoethanol,
and stimulated with LPS (10 μg/ml) or Con A (1.0
μg/ml) for 24 h. The cell culture supernatants were collected, stored
at -20°C. The cell culture supernatants were assayed f or IL-6 and
TNF-α, using the Porcine IL-6 Quantikine ELISA kit (Cat. No.
P6000) and Porcine TNF-α Quantikine ELISA Kit (Cat. No. PTA00)
according to the manufacturer’s instructions (R&D Systems,
Minneapolis, MN, USA). Optical density of each well was measured
within 30 min, using a microplate reader (Optimax, Molecular
Devices, USA) set to 450 nm (correction wavelength set at 570 nm).
Each experiment was run in duplicate and the results represent
means of three repeat experiments.
Statistical analysis
Data were analyzed using the general linear models of SAS (2003)
to estimate variance components with a completely randomized
design. Duncan’s multiple comparison tests were used to examine
significant differences among the treatment means. The level of
significance was set at P < 0.05. Data are presented as mean
values ± SE.
RESULTS
Growth performance, carcass characteristics and
meat quality
Body weight, weight gain, feed intake and feed
conversion ratio of different dietary groups are given in
Table 2. The initial body weight did not differ significantly
but the final body weight and body weight gain
were lower (P < 0.05) in the GTB-2% group when
compared to the antibiotic group. GTB-2% group
exhibited a higher feed intake relative to GTB-0.5% and
the control group and the FCR was also low when
comparing to the other groups (P < 0.05). Different levels
of GTB affect the proximate composition of loin meat
(Table 3). When pigs were fed a diet containing GTB-2%,
the crude fat decreased to the same level as the
antibiotic group (P < 0.05). The GTB 0.5% group had a
lower crude protein content, which was followed by the
GTB-1% group (P < 0.05); however, higher value (GTB-
2%) was not different than the antibiotic group.
Table 4 shows that the pigs in control group had a
higher (P < 0.05) slaughter weight than the GTB-0.5 and
2% groups. There were no significant differences (P >
0.05) in back fat thickness, carcass grade, water holding
capacity and pH among the groups; however, the shear
value was higher in the GTB-0.5% group relative to the
other GTB groups and the heating loss was lower in the
GTB-2% group when compare to the others groups (P <
0.05). No differences in meat color, juiciness and flavor
were observed due to supplementation with GTB,
although the tenderness was lower in GTB-0.5% group
(P < 0.05).
Biochemical and hematological parameters of blood
and oxidative stability of meat
The effects of green tea by-products on the biochemical
and hematological parameters of finishing pigs are
presented in Table 5. There were no significant
differences in total cholesterol, glucose, total protein,
albumin, globulin, albumin/globulin (A/G) ratio, BUN and
hemoglobin contents of the blood when the diets
contained 0.5 to 2% of GTB. Although no significant
differences were observed, the cholesterol level tended
to decreased (P > 0.05) with an increase in the GTB
content. WBC and RBC were increased (P < 0.05) at the
highest GTB concentration (2%). TBARS values for the
different treatment groups at different weeks are
presented in Figure 1.
Significant differences (P < 0.05) were observed
among treatments except fresh, 4th week and average