166 Intracytoplasmic morphological evaluation of Bos indicus bull sperm
P. Patel A , V. Suthar B , B. Suthar A , M. Joshi C , D. Patil B and C. Joshi CA College of Veterinary Science and Animal Health, Sknagar, Kamdhenu University, Datiwada, Gujarat, India
B Directorate of Research, Kamdhenu Uniiversity, Gandhinagar, Gujarat, India
C Gujarat Biotechnology Research Centre, Gandhinagar, Gujarat, India
Reproduction, Fertility and Development 35(2) 210-210 https://doi.org/10.1071/RDv35n2Ab166
Published: 5 December 2022
© 2023 The Author(s) (or their employer(s)). Published by CSIRO Publishing on behalf of the IETS
Morphologically selected sperm evaluation (MSE) is a tool used in human assisted reproduction before performing ICSI. However, information is lacking for bull spermatozoa. The objective of the present study was to evaluate the MSE technique for Bos indicus bull sperm and its association with macro and microscopic parameters of Kankrej bull semen before and after cryopreservation. In total,15 ejaculates were collected from three Kankrej bulls using an artificial vagina. The fresh semen was evaluated for volume (mL), colour and consistency (1–4 grade), seminal pH, sperm concentration (million/mL), mass motility ([MM] 0–5 scale), individual ([IM] %), sperm viability ([SV] %), sperm abnormalities ([SA] %), hypo-osmotic swelling test ([HOST] %), acrosome integrity ([AI] %), and morphometry (MP) using ×40 lens and NIS Elements software (Nikon), and MSE. The ejaculates were extended with Tris-fructose egg yolk glycerol (TFYG) dilutor and cryopreserved in LN2. After cryopreservation, the semen was evaluated for post-thaw motility ([PTM] %), SV, SA, HOST, AI, MP, and MSE. The real-time MSE was performed using 7% PVP media under ×8,500 lens with an inverted microscope; sperm were graded into four groups according to the presence or size of the vacuoles (GI: No vacuoles; G-II: <2 small vacuoles; G-III: >2 small vacuoles or at least 1 large vacuole; G-IV: 2 large vacuoles with other head abnormalities). The cryopreservation effect was analysed using independent t-test. The association between microscopic attributes of fresh and post-thawed semen of bulls was evaluated using Pearson correlation. Cryopreservation affected PTM, SV, HOST, and AI (P < 0.01). Overall mean values for sperm morphometry head length (HL), mid-piece length, head width, head width at base, and head shape (µm) were 8.48 ± 0.02, 14.0 ± 0.02, 4.54 ± 0.01, 2.21 ± 0.01, and 0.53 ± 0.002 (µm) for fresh semen and corresponding values for post-thawed semen were 8.40 ± 0.01, 13.95 ± 0.02, 4.51 ± 0.01, 2.20 ± 0.01, and 0.53 ± 0.002 (µm). Cryopreservation affected HL of sperm (P < 0.001); in fresh semen, the overall mean percentage of sperm head abnormalities decreased by 8.07, and for GI in frozen sperm compared with fresh, as they increased by 2.20, 2.40, and 3.6% for GII, GIII, and GIV, respectively, in post-thaw (P < 0.01). The results of this pioneer study demonstrated that MSE enables real-time evaluation of sperm abnormalities and shows association with other sperm evaluation tests. Hence, a noninvasive method like MSE could be a valuable tool to evaluate bull sperm abnormalities in real time.
