SUMMARYGoldfish and crucian carp at low temperature exhibit plasticity in gill morphology during exposure to hypoxia to enhance gas exchange. Hypoxia-induced changes in gill morphology and cellular ultrastructure of the high altitude scaleless carp from Lake Qinghai, China, were investigated to determine whether this is a general characteristic of cold water carp species. Fish were exposed to acute hypoxia (0.3·mg·O 2 ·l -1 ) for 24·h followed by 12·h recovery in normoxic water (6·mg·O 2 ·l -1 at 3200·m altitude), with no mortality. Dramatic alterations in gill structure were initiated within 8·h of hypoxia and almost complete by 24·h, and included a gradual reduction of filament epithelial thickness (>50%), elongation of respiratory lamellae, expansion of lamellar respiratory surface area (>60%) and reduction in epithelial water-blood diffusion distance (<50%). An increase in caspase 3 activity in gills occurred following 24·h exposure to hypoxia, indicating possible involvement of apoptosis in gill remodeling. Extensive gill mucous production during hypoxia may have been part of a general stress response or may have played a role in ion exchange and water balance. The large increase in lamellar surface area and reduction in diffusion distance presumably enhances gas transfer during hypoxia (especially in the presence of increased mucous production) but comes with an ionoregulatory cost, as indicated by a 10 and 15% reduction in plasma [Na

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In this study, coccidia were isolated and identified from 5 main poultry farms located in Zhejiang province, eastern China. The overall prevalence of Eimeria spp. was 30.7% (95 of 310). Five common species were observed: E. tenella, E. acervulina, E. maxima, E. necatrix, and E. mitis. Two isolates (HZ and QZ) were tested for sensitivity to 8 anticoccidial drugs using 4 indexes including anticoccidial index (ACI), percent of optimum anticoccidial activity (POAA), reduction of lesion scores (RLS), and relative oocyst production (ROP): sulfachloropyrazine, toltrazuril, diclazuril, sulfamonomethoxine/trimethoprim, and amprolium; sulfaquinoxaline/sulfadimethoxine, nicarbazin, and halofuginone. The results showed that the 2 isolates have developed various degrees of resistance to most of the tested drugs. The multi-resistance coccidia are a potential threat to local poultry farming. Rotation of anticoccidial drugs and shuttle programs are recommended to prevent further economic losses caused by coccidiosis.

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Spine-associated Rap-specific GTPase-activating protein (SPAR) is a postsynaptic protein that forms a complex with postsynaptic density (PSD)-95 and N-methyl-D-aspartate receptors (NMDARs), and morphologically regulates dendritic spines. Mild intermittent hypoxia (IH, 16.0% O2, 4 h/day for 4 weeks) is known to markedly enhance spatial learning and memory in postnatal developing mice. Here, we report that this effect is correlated with persistent increases in SPAR expression as well as long-term potentiation (LTP) in the hippocampus of IH-exposed mice. Furthermore, an infusion of SPAR antisense oligonucleotides into the dorsal hippocampus disrupted elevation of SPAR expression, preventing enhanced hippocampal LTP in IH-exposed developing mice and also reducing LTP in normoxic mice, without altering basal synaptic transmission. In SPAR antisense-treated mice, acquisition of the Morris water maze spatial learning task was impaired, as was memory retention in probe trails following training. This study provides the first evidence that SPAR is functionally required for synaptic plasticity and contributes to the IH-induced enhancement of spatial learning and memory in postnatal developing mice.