Table 4.

Effect of the addition of serine on unfrozen or frozen-thawed chicken sperm characteristic.

Serine (mmol)		Vigor score (1–5)	Membrane integrity (%)
Unfrozen semen (incubated for 24 h)	0	4.52 ± 3.08a,b,c	88.49 ± 5.00a,b
	1	4.41 ± 4.10b,c	86.48 ± 3.37b,c
	2	4.66 ± 2.37a	89.55 ± 2.48a,b
	4	4.71 ± 3.11a	92.31 ± 4.17a
	6	4.55 ± 2.53a,b	87.48 ± 4.14b
	8	4.43 ± 4.21b,c	85.63 ± 4.66b,c
	10	4.33 ± 3.42c	82.98 ± 4.05c
	15	4.32 ± 3.04c	78.98 ± 3.57d
	20	4.11 ± 4.22d	73.44 ± 3.04e
Frozen-thawed semen	0	3.53 ± 4.27b	39.21 ± 3.25b,c
	1	3.45 ± 5.06b	39.41 ± 3.89b,c
	2	3.65 ± 3.20a,b	40.78 ± 3.21b
	4	3.84 ± 2.54a	44.35 ± 4.03a
	6	3.49 ± 4.07b	41.23 ± 2.32b
	8	3.12 ± 3.65c	37.56 ± 3.50c
	10	3.13 ± 4.14c	35.10 ± 3.85d
	15	3.01 ± 3.45c	29.20 ± 2.87e
	20	2.89 ± 3.16d	22.14 ± 3.26f

The results are expressed as means ± standard deviations. N = 6. Different letters (^a–f) indicate significant differences within columns (P < 0.05).