Immune Cell Population in Oviducts in Relation to Ovarian and Progesterone Status of Anoestrous and Repeat Breeding Gilts

Abstract

The aim of the present study is to determine the distribution of immune cells within the endosalpinx related to the ovarian function in gilts culled due to repeat breeding and anoestrus. A total of 30 reproductive organs from culling crossbred Landrace x Yorkshire gilts were collected from commercial swine herds in Thailand and categorized
into 3 groups, i.e. anoestrus, repeat breeding and non-involved in reproductive disorder gilts (control group). The ovaries and oviducts were separated from the reproductive tracts and macroscopically investigated. The oviducts were divided into the utero-tubal junction (UTJ), the isthmus, the ampulla and the infundibulum. The gilts were classified according to ovarian appearance into the follicular and luteal phases. The results showed that lymphocytes were the most dominant immune cells found in all segments and in both phases of the control and culling gilt oviducts. In the epithelium, the numbers of lymphocytes in UTJ and the isthmus of anoestrous and repeat breeding gilts were significantly greater than the control group at luteal phase (p<0.05). The neutrophils in UTJ epithelium of repeat breeding gilts were higher than the control gilts at both the follicular and luteal phases (p<0.05), whereas, the macrophages in the repeat breeding gilts were found significantly higher than the control gilts only at follicular phase (p<0.05). In the subepithelial layer, the numbers of lymphocytes in the infundibulum of anoestrus gilts were
significantly greater than the control group at both stages (p<0.001), whereas, the plasma cells in the infundibulum of repeat breeding gilts were higher than the control group at both stages (p<0.001) as well. Furthermore, the other immune cells, i.e. neutrophils, macrophages and eosinophils, in the UTJ also had the unusual numbers in both culling
gilts compared to the control gilts (p<0.05). In conclusion, the irregular infiltration of various immune cells appeared in the epithelial and subepithelial layers of the oviduct, especially in the site of the sperm reservoir, possibly
indicating improper oviductal functions in both anoestrus and repeat breeding gilts.