Resveratrol and lycium barbarum polysaccharide improve Qinling giant panda (Ailuropoda melanoleuca Qinlingensis) sperm quality during cryopreservation

Background Semen cryopreservation has become an essential tool for conservation efforts of the giant panda (Ailuropoda melanoleuca); however, it is severely detrimental to sperm quality. Evidence has shown that antioxidants have the potential to reverse cryopreservation-induced damage in sperm. The purpose of this study was to screen effective antioxidants that could retain sperm quality during cryopreservation and to determine the optimal dose. Seven antioxidant groups, including resveratrol (RSV = 50 μM, RSV = 100 μM, RSV = 150 μM), lycium barbarum polysaccharide (LBP = 2 mg/mL, LBP = 4 mg/mL), laminaria japonica polysaccharides (LJP = 1 mg/mL) or combination (LBP = 2 mg/mL, LJP = 1 mg/mL and RSV = 100 μM) were assessed. Results RSV, LBP, LJP, or a combination of RSV, LBP, and LJP added to the freezing medium significantly improved sperm progressive motility, plasma membrane integrity, acrosome integrity, and mitochondrial activity during the cryopreservation process. Furthermore, the activities of glutathione peroxidase and superoxide dismutase were also improved. The levels of reactive oxygen species and malondialdehyde in semen were notably reduced. Hyaluronidase activity and acrosin activity were significantly increased in LBP-treated sperm. However, sperm total motility and DNA integrity were not significantly different between the groups. Conclusions RSV (50 μM) or LBP (2 mg/mL) are the best candidate antioxidants for inclusion in the freezing medium to improve the quality of giant panda spermatozoa during semen cryopreservation.

Impacts of Social Trust on Rural Households’ Attitudes towards Ecological Conservation—Example of the Giant Panda Nature Reserves in China

Understanding rural households’ conservation attitudes is crucial to achieving biodiversity conservation effectiveness, and one underlying predictor of household conservation attitudes is social trust. This study examined the impact of rural households’ social trust on their ecological protection attitudes based on 922 rural household data around 13 giant panda nature reserves in Shaanxi Province and Sichuan Province, China. The results show that: (1) Social trust has a significant positive impact on rural households’ conservation attitudes. (2) Males’ ecological conservation attitudes are influenced by all the social trust variables, whereas females’ attitudes are influenced mainly by interpersonal trust (trust in neighbors and villagers). The conservation attitudes of households with higher education levels and higher family incomes are mainly affected by trust in government, while those with lower education levels and lower family incomes are more significantly affected by the trust in villagers and village cadres. The above conclusions are helpful to understand the influencing mechanism of rural households’ conservation attitudes and improve the protection effects of nature reserves.