Effect of CALSEAGROW on laying hen antioxidant reserve and egg quality (2019)
Introduction
Throughout its production cycle, laying hen is exposed to different sources of physiological, environmental or nutritional stress. To defend itself, laying hen has endogenous or exogenous antioxidants (obtained through feed). Strong correlations have been demonstrated between different metabolic or inflammatory issues and an antioxidant deficit. This deficit, called oxidative stress, is associated with an increase in oxidative phenomena (lipid peroxidation, oxidation of proteins…) inducing a weakening of the intestinal mucosa, an alteration of the intestinal microbiota balance and a degradation of egg quality. The objective of this trial is to determine the effect of CalseaGrow (1kg/t) on antioxidant laying hen reserve and egg quality.
Material and Method
- A total of 574 laying hens were housed during 10 weeks from 68 to 79 weeks old (12 hens/cage)
- Randomly distributed in 2 treatments with 12 replicates
- T1 (Control) : Basal diet
- T2 (CalseaGrow) : Basal diet + CalseaGrow at 1 kg/t of feed
- Antioxidant reserve parameter monitored: RESEDA test from blood sampled at 74 and 78 weeks old
- Egg quality parameters monitored : Vitelline membrane rigidity and Haugh unit at 78 weeks old
Results and Discussion
Research has shown that ovarian oxidative stress increases with age and that the expression levels of antioxidation-related genes decreased (Liu et al, 2020). Antioxidant capacity of layers can be measured through KRL and/or RESEDA test. The KRL test evaluates the effectiveness of the circulating antiradical defense of a blood sample by quantifying the half-hemolysis time (T1/2). It is the time required to hemolyze by oxidation 50% of the sample. The more important this T1/2 is, the more it represents a good defense of antioxidants, which slow down the oxidation. The RESEDA test is very close to the KRL test except that it allows to release the different reserves of antioxidants contained in the cells (Prost, 2013). Stored antioxidants are released during this test via the addition of different enzymes: Glucosidase (for R1 reserves), Sulfatase (for R2 reserves) and Glucuronidase (for R3 reserves).
CalseaGrow increases the half-hemolysis time (T1/2), mainly in the form of reserves R1 and R3 in the laying hen (cf. Graphic 1). It means a better resistance to oxidation and can be explained by the capacity of CalseaGrow to provide natural antioxidants that are stored in laying hen cells.
During oxidative stress, free radicals are responsible of cell damages such as lipid peroxidation and proteins oxidation. The vitelline membrane, composed of lipids, is one of the essential parameters related to egg quality and embryo development (cf. Figure 1). CalseaGrow demonstrates a significative improvement of this membrane rigidity by 2.4% at 78 weeks old (cf. Graphic 2). It means a better resistance to breakage which is useful for breaking factories (egg white / egg yolk separation) and hatcheries (ensures good white / yellow separation, which facilitates the development of embryo and thus increases the hatching rate).
Another important parameter related to egg quality and freshness is the Haugh Unit. It measures the thickness of the albumen (egg white) which is rich in proteins. With CalseaGrow supplementation, Haugh unit is significantly increased by 3.1% allowing to attend a higher egg classification quality at 78 weeks old (cf. Figure 2).
(HU = 100 log (H – 1.7 EW0,37 + 7.57) ;EW : Egg Weight ; H : Height of thick albumen)
Conclusion
Thanks to CalseaGrow antioxidant properties, yolk and albumen structure are improved which allows a better egg quality until the last weeks of laying production.