In this study the effect of extenders and temperatures on sperm viability and fertilizing capacity of boar sperm during long-term storage was investigated. Acrosomal integrity, membrane integrity, motility and hypo-osmotic resistance were evaluated by fluorescence and light microscopy. An in vitro fertilization test was performed to assess the fertilizing capacity of stored spermatozoa. The five diluents tested were ranked according to their ability to maintain sperm functional parameters and Zorlesco (ZO) extender with BSA or with PVA instead of BSA produced the best results. Zorlesco extender substituted with PVA (ZO+PVA) was found to maintain motility both at 15 and 20°C within 5 days of storage, but the quality of semen stored at 15°C decreased thereafter as compared to semen stored at 20°C. Semen stored at 5°C demonstrated rapid loss of motility already within 24 h. Both fertilization and cleavage of semen stored at 20°C in ZO substituted with PVA instead of BSA did not change significantly until day 8 of storage. It is therefore concluded that PVA can be used to substitute for BSA and 20°C was more suitable than 15°C for boar semen storage, and in vitro fertilizing capacity of spermatozoa was maintained for at least 8 days in ZO+PVA at 20°C.

The research on the enantioselective toxic effects of chiral pesticides on non‐target aquatic organisms has attracted more and more attention. This study investigated the enantioselective toxic effects of mefentrifluconazole (MFZ) on acute toxicity, developmental toxicity, locomotor behaviors, and the mRNA relative expression levels of genes related to neurodevelopment and cardiac development in zebrafish embryos or larvae. The 96‐h lethal concentration 50 (LC50) values (exposed to racemate and enantiomers of MFZ, that is, rac‐MFZ/(−)‐MFZ/(+)‐MFZ) were 1.010, 1.552, and 0.753 mg/L for embryo, and 0.753, 1.187, and 0.553 mg/L for larvae. The rac‐MFZ/(−)‐MFZ/(+)‐MFZ can affect the heart development of zebrafish embryos, accompanied by heart rate inhibition, yolk sac deformities, pericardial deformities, and down‐regulation of genes related to cardiotoxicity in larvae in an enantioselective manner. Moreover, the rac‐MFZ/(−)‐MFZ/(+)‐MFZ also can affect the neural development of zebrafish embryos, accompanied by autonomic movement inhibition, swimming speed and swimming distance abnormalities, and down‐regulation of genes related to neurotoxicity in larvae in an enantioselective manner. For all toxicity endpoints, the effect of the (+)‐MFZ to early‐staged zebrafish were significantly greater than that of (−)‐MFZ. These results will help distinguishing the difference of MFZ enantiomers to zebrafish, and provide scientific reference for improving the risk assessment of chiral pesticides MFZ.

Seminal plasma is a complex biological fluid containing many metabolites including amino acids, fructose, carbohydrates and lipids Metabolites play important roles in multiple biological processes, but details and significance of the seminal plasma metabolome related to boar fertility are unknown. The aim of the present study was to compare the comprehensive metabolome of seminal plasma from boars with different conception rate after artificial insemination and to identify the potential biomarkers. Semen samples were collected from boars which divided into two groups according to the conception rates in the offspring. Seminal plasma metabolites were isolated, purified, and then subjected to Ultra‐high Performance Liquid Chromatography‐Quadrupole Time‐of‐Flight Mass Spectrometry (UHPLC‐qTOF‐MS) procession. A total of 576 (Positive ion mode) and 377 (Negative ion mode) metabolites were identified in seminal plasma. Metabolites were identified and categorized according to their major chemical classes, including carboxylic acids and derivatives, organooxygen compounds, amino acids, peptides, and alogues, fatty amides, fatty acyls, benzene and substituted derivatives, purine nucleotides, pyrimidine nucleotides, glycosyl compounds, fatty acids and conjugates. The results showed that 4‐Aminobenzoate, Pro‐Asn, Ile‐Tyr, Homoveratric acid and D‐Biotin were higher in semen of boar with higher conception rate (HG) versus lower conception rate (LG) (p < .05), whereas L‐Serine, Butoxyacetic acid, S‐Methyl‐5'‐thioadenosine, Capsaicin and 1‐O‐(cis‐9‐Octadecenyl)‐2‐O‐acetyl‐sn‐glycero‐3‐phosphocholine (PAF) were lower in HG than in LG (p < .05). These metabolites may be considered as candidate biomarkers for different fertility in boars.

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