Effect of membrane stabilizers on semen quality and sperm membrane protein expression during cryopreservation of goat semen.

BACKGROUND: Semen cryopreservation is a complex process during which there is alteration in the expression of sperm and seminal plasma proteins, molecular weight of protein or loss of membrane proteins during the process. In order to compensate for these changes, different membrane stabilizers are used in freezing semen extenders. However, there is scarcity of such studies during cryopreservation of goat semen. OBJECTIVE: To investigate the effect of membrane stabilizers on sperm membrane protein expression during cryopreservation of goat semen. MATERIALS AND METHODS: A total of 36 semen ejaculates from nine Assam Hill Goat bucks aged 2 to 2.5 years was collected by artificial vagina method. Three membrane stabilizers, each at two different concentrations viz. 50 and 80 mM sucrose, 50 and 100 mM trehalose, and 100 and 150 ng per mL IGF-1 (insulin-like growth factor 1 protein) were added to Tris-citric acid fructose egg yolk glycerol (TCFEYG) extender and semen samples were cryopreserved. The sperm membrane protein profile was studied in fresh and cryopreserved semen by SDS-PAGE. RESULTS: SDS- PAGE of sperm membrane extract of fresh semen revealed the presence of 24 protein bands with molecular weights ranging from 10 kDa to 240 kDa. Samples supplemented with 50 mM sucrose and 80 mM sucrose revealed 21 protein bands with molecular weights ranging from 10 kDa to 240 kDa. All the 21 protein bands were same as those observed in the sperm membrane of fresh spermatozoa, except that the 23 kDa, 29 kDa and 42 kDa bands were absent in frozen semen. Similarly, frozen semen extended with 50 mM trehalose and 100 mM trehalose revealed 22 protein bands with molecular weights ranging from 10 kDa to 240 kDa, but lacking the 29 kDa and 42 kDa bands. Proteins with molecular weights of 29 kDa, 130 kDa and 240 kDa were absent in frozen semen supplemented with 100 ng per mL IGF-1 and 150 ng per mL IGF-1. CONCLUSION: The present study revealed that supplementation of tris basic extender with trehalose at 100 mM and or IGF-1 at 100 ng/mL or 150 ng per mL improves the post-thaw semen characteristics and protects certain fertility related sperm membrane proteins. Doi.org/10.54680/fr23510110612.

Body status and blood metabolites profiles during resumption of postpartum ovarian activity in yak (Poephagus grunniens).

We examined the changes in body weight (BW), back-fat thickness (BFT) and blood metabolites in relation to postpartum (PP) ovarian activity status in twenty female yaks raised under semi-intensive system. BFT and ovarian activities, like follicle development, ovulation (OV) and corpus luteum (CL) development, were monitored from 4 to 15 weeks (wk) PP using ultrasonography. Resumption of ovarian activity was confirmed with ovulation of dominant follicle (DF) and subsequent CL development, and >1 ng/ml progesterone concentration in blood plasma sample after 1week of ovulation. Yaks were further classified as cyclic (with CL), acyclic (without CL), and cystic (with >25 mm follicular cyst; FC). Within 20 weeks PP, 60% yaks resumed cyclic ovarian activity, while 25% failed to initiate cycling activity, and 15% developed follicular cysts. In all categories of yak, BW gradually decreased (p < .05) till nadir; however, nadir reached earlier (p < .05) in acyclic yaks. BFT differed (p < .05) among the yak groups, but it tended to be higher in cyclic yaks as compared to acyclic and cystic. No difference (p > .05) in non-esterified fatty acids (NEFA) values was found among the different categories of yaks, whereas, beta-hydroxy butyrate (BHB) levels were higher in cystic animals as compared to acyclic and cyclic. Blood glucose levels decreased in all yaks during initial 2 weeks after calving. Our findings suggest that yaks with low BW, BFT and glucose levels, and higher BHB values were at risk of delayed resumption of ovarian activity and concomitant development of follicular cysts.