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Our objectives were to explore the effect of naringenin addition in the semen extender on the post-thaw 1) sperm quality, 2) fertility-associated gene expression, and 3) fertilization potential of buffalo bull sperm. In experiment 1, semen samples (n = 32) from four Nili-Ravi buffalo bulls were pooled (n = 8) and diluted with the tris-citric acid (TCF-EY) extender containing different concentrations of naringenin, i.e., placebo (DMSO), 0 (control), 50, 100, 150 and 200 μM naringenin. After dilution, semen samples were packed in 0.5 mL French straws, cryopreserved and analyzed for post-thawed sperm quality and gene expression. Computer-assisted Semen Analysis, Hypo-osmotic Swelling test, Normal Apical Ridge assay, Rhodamine 123, Acridine orange, Propidium iodide staining and Thiobarbituric Acid Reactive Substances assay were performed to assess sperm motility parameters, plasma membrane functionality, acrosome integrity, mitochondrial membrane potential, DNA integrity, viability and lipid peroxidation, respectively. Expression levels of sperm acrosome-associated SPACA3, DNA condensation-related PRM1, anti-apoptotic BCL2, pro-apoptotic BAX, and oxidative stress-associated ROMO1 genes were evaluated through qPCR. Results revealed that total and progressive motility, plasma membrane functionality, acrosome integrity, mitochondrial membrane potential, DNA integrity and viability were higher (P < 0.05) with 50, 100 and 150 μM naringenin compared to 200 μM naringenin, placebo and control groups. Moreover, all naringenin-treated groups improved catalase activity, and reduced lipid peroxidation compared to placebo and control groups (P < 0.05). Relative expression levels of SPACA3 and PRM1 genes were higher (P < 0.05) with 150 μM naringenin compared to all groups except 100 μM (P > 0.05). No difference (P > 0.05) in the expression level of BCL2 gene was observed among all groups. Furthermore, BAX gene was expressed higher (P < 0.05) in the 200 μM naringenin group, whereas no difference (P > 0.05) in expression was noticed among the remaining groups. In addition, ROMO1 gene was expressed lower (P < 0.05) in all naringenin-treated groups compared to the control. In experiment 2, the in vivo fertility of semen doses (n = 400; 200/group) containing optimum concentration of naringenin (150 μM; depicted better in vitro sperm quality in experiment 1) was compared with control during the breeding season. Buffaloes were inseminated 24 h after the onset of natural estrus and palpated transrectal for pregnancy at least 60 days post-insemination. The fertility rate of 150 μM naringenin group was higher (P = 0.0366) compared to the control [57.00 ± 0.03 % (114/200) vs. 46.50 ± 0.04 % (93/200), respectively]. Taken together, it is concluded that naringenin supplementation in semen extender improves post-thaw quality, fertility-associated gene expression and fertilization potential of buffalo bull sperm, more apparently at 150 μM concentration., Competing Interests: Declaration of competing interest The authors declare that they have no conflict of interest regarding the publication of this research article., (Copyright © 2024 Society for Cryobiology. Published by Elsevier Inc. All rights reserved.)

Cryopreservation affects integrity of cholesterol and phospholipids in the plasma membrane of sperm leading to decreased fertility of frozen-thawed semen. Cholesterol-loaded cyclodextrins (CLC) have been shown to improve post-thaw semen quality in various species. The aim of this study was to investigate the optimal concentration of CLC for better post-thaw semen quality in dogs. Semen collection, through digital manipulation, was conducted once a week in four adult German shepherd dogs (n = 20 ejaculates; five ejaculates/dog). Semen samples with mass motility>3 (0: without movement; 5: fast progressive movement), motility >70% and concentration >200 × 10 6 /ml were pooled and processed in Tris-citrate extender containing 0, 1, 2 or 3 mg of CLC. The post-thaw quality was assessed on the basis of percentage motility, morphological abnormalities, live/dead ratio and plasma membrane, acrosome and DNA integrity, evaluated using anova and further analysed by Tukey's range test, if applicable. The addition of CLC showed an overall improvement in post-thaw semen quality. Among various treatment groups, and when compared to the control, the percentages of motile (55.5%), viable (65%), plasma membrane intact (56.7%), acrosome intact (49.2%) and DNA intact (98%) spermatozoa were significantly higher in 2 mg/ml CLC group (p < .05). It is concluded that incorporation of cholesterol in semen extender results in a beneficial increase in post-thaw semen quality in dogs., (© 2017 Blackwell Verlag GmbH.)