Table 4 Effect of four successive weeks supplementation of Lactulose (Vetelact) on internal and external egg quality (mean ± SE) in layer chickens

Egg weight (g)

59.10 ± 0.54^b

61.54 ± 0.49^a

61.53 ± 0.63^a

61.10 ± 0.44 ^a

0.003

Egg index %

80.27 ± 0.41

80.22 ± 0.39

80.00 ± 0.34

80.45 ± 0.43

0.883

Shell Deformation µm

19.1 ± 0.39

19.48 ± 0.33

19.15 ± 0.39

19.90 ± 0.34

0.385

Yolk diameter (cm)

4.09 ± 0.26^c

4.17 ± 0.02^ab

4.21 ± 0.02^a

4.13 ± 0.02^bc

0.002

Albumin height(mm)

8.21 ± 0.20

8.41 ± 0.24

8.19 ± 0.27

8.05 ± 0.2

0.748

Yolk height (mm)

20.12 ± 0.20

20.43 ± 0.18

20.56 ± 0.19

20.15 ± 0.16

0.248

Yolk weight (g)

15.44 ± 0.16^b

15.95 ± 0.2^ab

16.24 ± 0.19^a

16.04 ± 0.19^a

0.018

Shell weight (g)

7.13 ± 0.08^b

7.38 ± 0.08^a

7.43 ± 0.09^a

7.37 ± 0.06^a

0.034

Albumin weight (g)

36.53 ± 0.44^b

38.22 ± 0.47^a

37.86 ± 0.58^ab

37.68 ± 0.44^ab

0.041

shell thickness (10⁻² mm)

38.91 ± 0.41^b

40.05 ± 0.38^a

40.91 ± 0.4^a

40.33 ± 0.34^a

0.003

Yolk index

0.49 ± 0.004

0.49 ± 0.005

0.48 ± 0.005

0.48 ± 0.003

0.881

Haugh unit

90.51 ± 0.99

90.66 ± 1.26

89.33 ± 1.36

89.03 ± 1.07

0.695