Table 4 Effect of dietary natural astaxanthin (ASTA) supplementation on the semen volume, sperm viability, and sperm concentration of aging layer breeder roosters

Semen volume, mL

0

0.25

0.26

0.26

0.24

0.005

0.606

0.769

0.199

2

0.25^b

0.31^a

0.27^b

0.27^b

0.006

< 0.01

0.429

< 0.01

4

0.24^b

0.31^a

0.29^a

0.29^a

0.006

< 0.01

< 0.01

< 0.01

6

0.25^b

0.34^a

0.32^a

0.31^a

0.054

< 0.01

< 0.01

< 0.01

Sperm viability, %

0

83.83

81.33

82.17

82.83

0.420

0.185

0.549

0.060

2

85.33^b

89.17^a

90.83^a

90.83^a

0.650

< 0.01

< 0.01

0.063

4

83.17^c

88.67^b

90.17^ab

91.50^a

0.750

< 0.01

< 0.01

0.011

6

85.67^c

91.33^ab

91.00^b

94.67^a

0.870

< 0.01

< 0.01

0.400

Sperm concentration, 10⁸/mL

0

11.36

11.28

11.30

11.37

3.150

0.742

0.862

0.291

2

11.37^b

11.49^b

11.84^a

11.96^a

5.427

< 0.01

< 0.01

0.931

4

11.37^c

12.04^b

12.15^b

12.42^a

8.489

< 0.01

< 0.01

< 0.01

6

11.33^c

12.57^b

12.62^b

12.97^a

13.523

< 0.01

< 0.01

< 0.01