Ovalbumin expression in the oviduct magnum of hens is related to the rate of egg laying and shows distinct stress‐type‐specific responses

Abstract

Three trials were performed to evaluate the association of ovalbumin (OVA) abundance in the oviduct magnum with egg production and the underlying regulatory mechanism by glucocorticoids. In trial 1, twenty Hy-Line Brown layers (56-60 weeks of age) with different combinations (n = 5/combination) of laying rate (high or low) and egg weight (high or low) were selected from an initial group of 300. An upregulated expression of magnum OVA was observed (p < 0.05) in hens with higher laying rate, regardless of egg weight. In trial 2, eighty Hy-Line Brown layers (80-90 weeks of age) were subjected to the forced moulting (n = 8). The abundance of OVA transcript and protein in the magnum was significantly decreased during moulting (p < 0.01), and the same was true for laying rate (p < 0.01) and serum oestrogen (p < 0.05). In trial 3, forty-five 56-week-old Hy-Line Brown layers were kept individually (n = 15) in the following conditions for 10 days: constant optimal ambient temperature at 23 °C and ad libitum feeding, high ambient temperature at 32 °C for 6 h/day (10:00-16:00) and ad libitum feeding (32AL), and constant optimal ambient temperature at 23 °C and pair-fed to the 32AL hens. In spite of elevated corticosterone in circulation, OVA synthesis, blood oestrogen and laying rate were not affected by heat exposure (p > 0.05). These results allow concluding that OVA expression in the oviduct magnum of hens is related to the rate of egg laying and shows distinct stress-type-specific responses.

Molecular signatures of epithelial oviduct cells of a laying hen (Gallus gallus domesticus) and quail (Coturnix japonica)

“…On the other hand, OVAL and OVM , which encode major egg white proteins, were expressed only in the magnum. Such a pattern of the gene expression across the avian oviduct has been widely reported in the literature [ 24 , 25 ] and it validates the functional setup of this experiment.…”

Identification of reliable reference genes for expression studies in the magnum of laying hens housed in cage and cage‐free systems

“…Magnum is the most important reproductive tissue for synthesis and secretion of the egg white proteins, including ovalbumin, lysozyme, ovotransferrin, ovomucin and avidin, among others (Nys et al., 2001; Socha & Hrabia, 2018). However, multiple biotic and abiotic factors, including the nutrition and production system, could affect the gene expression in the oviduct and the translation of some proteins present in the matrix of the albumen, such as ovalbumin and ovomucin (Zhao et al., 2016), altering the egg components affecting the internal quality and egg (Jung et al., 2011; Sah & Mishra, 2018; Saleh et al., 2019).…”

Effects of dietary methionine on productivity, reproductive performance, antioxidant capacity, ovalbumin and antioxidant-related gene expression in laying duck breeders

“…The breeders were then stunned, exsanguinated and the ovaries were collected and weighed. Samples were collected from the liver, oviduct magnum and ovaries ( 23 , 24 ) , which were rinsed rapidly with PBS, snap-frozen in liquid N 2 and stored at −80°C. After hatching, twelve ducklings from each treatment group (two ducklings from each replicate) were stunned, exsanguinated and samples of the liver and brain ( 25 ) were harvested, rinsed quickly with PBS, snap-frozen in liquid N 2 and stored at −80°C.…”