Effect of three schemes of ovum pick‐up on the follicular dynamics, gene expression, and in‐vitro developmental competence of oocytes in Sahiwal cattle. Issue 10 (11th July 2022)

• Record Type: Journal Article
• Authors: Saleem, Muhammad; Yousuf, Muhammad Rizwan; Ghafoor, Aamir; Riaz, Amjad
• Is Part Of: Reproduction in domestic animals. Volume 57:Issue 10(2022)
• Page Start: 1230
• Page End: 1243
• Publication Date: 2022-07-11
• Subjects: in‐vitro embryo production -- ovum pick‐up interval -- Sahiwal cattle; Animal breeding -- Periodicals; Veterinary pathology -- Periodicals; Livestock -- Breeding -- Periodicals; 636.082
• DOI: 10.1111/rda.14198
• Languages: English
• ISSNs: 0936-6768

Abstract

Abstract: This study aimed to compare the effect of three schemes of ovum pick‐up (OPU) on follicular dynamics, oocytes recovery, oocytes quality, gene expression, nuclear maturation and in‐vitro developmental competence of oocytes in Sahiwal cattle. Considering the follicle population, all the cows were divided equally in a 3 × 3 cross over design, and each cow received one of the three treatments: (a) twice weekly (TW; n = 6), (b) once weekly (OW; n = 6) and (c) bi‐weekly OPU (BW; n = 6) in three periods, with the first OPU conducted on 4, 7 and 14 days after second dominant follicle puncture (DFP) in the TW, OW and BW OPU interval groups, respectively. The collected cumulus oocytes complexes (COCs) were graded into A, B, C and D grades depending on the number of layers of cumulus cells and homogeneous nature of cytoplasm. Nuclear maturation was assessed by staining the oocytes with Hoechst 33342. The growth rate (mm/day) of dominant follicle (DF) (F1) (0.49 ± 0.21 vs. 0.71 ± 0.26 vs. 1.30 ± 0.27) and first subordinate follicle (F2) (0.85 ± 0.27 vs. 0.71 ± 0.25 vs. 1.06 ± 0.29) did not differ ( p > .05) among all the three groups. The proportion of animals bearing a corpus luteum (CL) in the BW OPU interval group (53.3%) was significantly higher ( p < .05) as compared to TW (13.3%) and OW (18.3%) OPU interval groups. The number of medium‐sized follicles and oocyte with grade A and B were significantly higher ( p < .05) in the TW (1.16 ± 0.21 and 33.88 ± 0.03) OPU interval group as compared to the OW (0.88 ± 0.22 and 21.54 ± 0.03) and BW (0.55 ± 0.21 and 21.89 ± 0.02) OPU interval groups. However, the number of degenerated oocytes in BW (0.85 ± 0.16) OPU interval group was significantly higher ( p < .05) as compared to the TW (0.16 ± 0.15) and OW (0.44 ± 0.16) OPU interval groups. Expression level of growth differentiation factor 9 in TW OPU interval group was significantly higher ( p < .05) as compared to the OW and BW OPU interval groups. Likewise, expression level of bone morphogenetic protein 15 ( BMP15 ) in the TW and BW OPU interval groups was significantly higher ( p < .05) as compared to the OW OPU interval group. The nuclear maturation rate was significantly higher in the TW (63.64 ± 0.07) and BW (59.26 ± 0.08) OPU groups as compared to OW (51.43 ± 0.06) OPU interval group. However, the cleavage rate (59.30 ± 0.06 vs. 44.29 ± 0.06 vs. 56.67 ± 0.06) did not differ ( p > .05) among the three groups. Whereas, the blastocyst rate tended to be higher ( p = .06) in the TW (29.07 ± 0.05) and BW (28.33 ± 0.04) OPU interval groups as compared to OW (18.57 ± 0.05) OPU interval group. Taken together, it can be concluded that TW OPU interval scheme enhances the medium‐sized follicles resulting in good quality oocytes, regulates the oocyte‐derived paracrine factors, leading to higher nuclear maturation rates and improved embryonic development in‐vitro.