Protective influence of rosiglitazone against time‐dependent deterioration of boar spermatozoa preserved at 17°C

Spermatozoa are highly specialized cells, and energy metabolism plays an important role in modulating sperm viability and function. Rosiglitazone is an antidiabetic drug in the thiazolidinedione class that regulates metabolic flexibility and glucose uptake in various cell types, but its effects on boar sperm metabolism are unknown. In this study, we investigated the potential effect of rosiglitazone against time‐dependent deterioration of boar spermatozoa during liquid preservation at 17°C. Freshly ejaculated semen was diluted with Beltsville Thawing Solution (BTS) containing different concentrations of rosiglitazone, and the motility, membrane and acrosome integrity of sperm were detected. Besides, we measured glucose uptake capacity, l ‐lactate production level, mitochondrial membrane potential, adenosine triphosphate (ATP) content and mitochondrial reactive oxygen species (mROS) production of sperm after boar semen had been incubated with or without rosiglitazone, iodoacetate (glycolysis inhibitor) and rotenone (electron transport chain inhibitor) for 5 days. The addition of rosiglitazone significantly enhanced sperm quality and had a strong protective effect on the sperm membrane and acrosome integrity during storage. BTS containing 50 μM rosiglitazone maintained the total motility of liquid‐preserved sperm above 60% for 7 days. Rosiglitazone improved sperm quality by regulating energy metabolism manner of preserved sperm, protected the sperm mitochondrial membrane potential, enhanced sperm ATP production and in the meanwhile reduced mROS through enhancing glycolysis but not oxidative phosphorylation. The data suggested the practical feasibility of using rosiglitazone for improving boar spermatozoa quality during semen preservation.     

Glutathione content of in vivo and in vitro matured canine oocytes collected from different reproductive stages

Glutathione (GSH) concentrations of oocytes are considered as an important marker of the cytoplasmic maturation. The present study was designed to compare GSH concentrations of in vivo and in vitro matured canine oocytes. In vivo matured oocytes were collected 72 hr after ovulation by flushing fallopian tubes after laparotomy. Ovaries were collected from bitches with different reproductive stages, and collected oocytes were divided into 2 groups according to the size viz. < 120 microm and > 120 microm in diameter and cultured for 72 hr in Tissue Culture Medium-199 supplemented with 10% FBS, 2.2 mg/ml sodium bicarbonate, 2.0 microg/ml estrogen, 0.5 microg/ml FSH, 0.03 IU/ml hCG, and 1% penicillin-streptomycin solution in the presence or absence of 50 microM beta-mercaptoethanol. GSH concentrations were determined by the dithionitrobenzoic acid-glutathione disulfide (DTNB-GSSG) reductase recycling assay. GSH concentrations of immature canine oocytes were 2.9 and 3.8, 3.5 and 6.8, and 3.1 and 6.5 pM/oocyte for < 120 microm and > 120 microm in diameter oocyte groups at anestrous, follicular and luteal stage, respectively (P<0.05). In vivo matured oocytes had significantly higher GSH concentrations compared with in vitro matured oocytes. The GSH content was 19.2 pM/oocyte for in vivo matured oocytes, while 4.1 to 8.1 and 5.7 to 13.2 pM/oocyte for in vitro matured oocytes cultured in the absence or presence of beta-mercaptoethanol, respectively (P<0.05). Presence of beta-mercaptoethanol increased GSH synthesis in canine oocytes cultured in vitro, and oocytes collected from follicular and luteal stage was superior to anestrus oocytes.     

Effect of dietary nutmeg oil on heat‐stress tolerance‐related parameters in Korean native chicken reared under hot temperature

This study investigated the effect of dietary nutmeg oil (NO) on growth performance, blood parameters, lipid peroxidation and heat shock protein (HSP) 70 expression in Korean native chicken (KNC) reared under hot temperature. We allocated 273 meat‐type KNCs (Hanhyup‐3, 4‐week‐old, body weight [BW] = 539.93 ± 1.75 g) to the following three treatments with seven replicate pens (13 birds/pen) per treatment. Three treatment diets were as follows: (a) Control, basal diet without NO supplementation; (b) NO 250; and (c) NO 500, basal diet supplemented with 250 and 500 ppm NO respectively. Diets and water were provided ad libitum throughout the 6‐week feeding trial. During overall period (0–6 weeks), no differences (p > 0.05) were observed in BW gain (BWG), feed intake (FI) and feed conversion rate (FCR) among treatments. However, the FI at 0–3 weeks decreased (p < 0.05) quadratically with increasing NO levels. Most blood parameters did not differ (p > 0.05) among treatments, although the monocyte level of the NO 500 group was considerably lower (p > 0.05) than that of the other groups. Furthermore, dietary NO did not affect serum triglyceride, cholesterol, total protein, albumin, calcium, phosphorus and alanine aminotransferase (ALT) levels (p > 0.05); however, it linearly decreased serum aspartate aminotransferase (AST) level (p < 0.05). Additionally, serum malondialdehyde (MDA) concentration decreased (p < 0.05) and heart MDA concentration was lower (p = 0.08) with increasing dietary NO supplementation. After a 3‐hr heat (35°C) challenge, the rectal temperature (RT) reduced (p < 0.05) linearly with increasing NO levels. Dietary NO did not affect liver HSP70 (p > 0.05) gene expression. In conclusion, NO potentially enhanced the ability of chickens to alleviate heat stress. Furthermore, our findings suggest that lipid oxidation inhibition by dietary NO likely mediated the enhanced heat‐stress tolerance of the chickens.     

蛋鸡种蛋蛋重对孵化率和雏鸡生长发育的影响

将豫州褐壳蛋的种蛋按重量大小分成6组，在相同的条件下进行孵化和饲养试验。结果表明，蛋重在53－56克的种蛋，其受精蛋孵化率最高；不同的蛋重对雏鸡的初生重以及雏鸡在1－3周龄的体重影响较大，蛋重与初生重（γ=0．9899）、1周龄体重（γ＝0．9528）的相关极显著；蛋重与2周龄体重（γ＝0．9032）、3周龄体重（γ＝0．9040）相关显著，与3周龄以后雏鸡体重相关不显著。     

Comparative study on calretinin immunoreactivity in gerbil and rat retina

Expression of calretinin in retina has been ascribed to multiple biological and functional aspects in the visual system. In this study, we examined the distribution patterns of calretinin immunoreactivity in gerbil and rat retina. In the gerbil, calretinin immunoreactivity was present in bipolar and amacrine cells of the inner nuclear layer and in neurones of the ganglion cell layer. In the rat, amacrine and ganglion cells showed calretinin immunoreactivity, but bipolar cells did not contain calretinin immunoreactivity. In both species, calretinin immunoreactivity was absent in cones, cone bipolars, and horizontal cells. In conclusion, gerbil as well as rat has a rod-dominant retina. The differences in calretinin expression between rat and gerbil require further investigations under various functional and developmental conditions.     

生物安全三级实验室生物安全风险点的识别与控制?

BSL-3实验室须经国家生物安全认可和严格的实验活动审批才能开展相应活动,是国家(地区)开展高致病性病原微生物实验活动的重要技术支撑平台。实验室生物安全风险点易发生在样本及菌毒种的接收、传递和保存,动物实验,污水以及固体废弃物处理等环节,而实验室的意外事件(电力故障、火灾、积水等)与生物安保漏洞也会造成重大的生物安全事故。提示应准确地识别风险并通过人员日常监管、标准操作规程、两级屏障设施和个人防护装备等系列措施对生物安全风险点予以严格控制。     

β‐hydroxy‐β‐methyl butyrate promotes leucine metabolism and improves muscle fibre composition in growing pigs

The aim of this study was to investigate the effects of excess leucine (Leu) vs. its metabolites α‐ketoisocaproate (KIC) and β‐hydroxy‐β‐methyl butyrate (HMB) on Leu metabolism, muscle fibre composition and muscle growth in growing pigs. Thirty‐two pigs with a similar initial weight (9.55 ± 0.19 kg) were fed 1 of 4 diets for 45 days: basal diet, basal diet + 1.25% L‐Leu, basal diet + 1.25% KIC‐Ca, basal diet + 0.62% HMB‐Ca. Results indicated that relative to the basal diet and HMB groups, Leu and KIC groups exhibited increased Leu concentrations and decreased concentrations of isoleucine, valine and EAAs in selected muscle (p < 0.05) and had lower mRNA levels of MyHC I and higher expression of MyHC IIx/IIb (p < 0.05), and there was no significant difference between the basal and HMB‐supplemented groups. Moreover, the mRNA expression levels of AMPKα and UCP3 were higher but the myostatin mRNA levels were lower in the soleus muscle of the HMB group than those from other groups (p < 0.05). These findings demonstrated that doubling dietary Leu content exerted growth‐depressing effects in growing pigs; dietary KIC supplementation induced muscular branched‐chain amino acid imbalance and promoted muscle toward a more glycolytic phenotype; while dietary HMB supplementation promoted the generation of more oxidative muscle types and increased muscle growth specially in oxidative skeletal muscle, and these effects of HMB might be associated with the AMPKα‐Sirt1‐PGC‐1α axis and mitochondrial biogenesis.     

Molecular detection and characterization of unclassified bovine enteric caliciviruses in South Korea

The unclassified bovine enteric calicivirus (BEC) is a new bovine enteric calicivirus that is different from bovine norovirus, and causes diarrhea and pathologies in the small intestine of calves. This virus includes Nebraska (NB)- and Newbury agent 1 (NA1)-like strains. The prevalence of this BEC and its genetic characterization has only been reported in the UK and the USA. This study examined the prevalence and genetic diversity of these BECs in diarrheic calves in South Korea. Among a total of 645 diarrheic fecal specimens obtained from 629 cattle herds, these unclassified BECs were detected in 59 (9.1%) diarrheic fecal samples from 57 herds (9.3%) by either RT-PCR or nested PCR. Sequence and phylogenetic analyses of the partial RdRp gene showed that all the Korean BECs clustered together and were closely related to the NB-like viruses (80.9-88.1% nucleotide and 84.5-98.4% amino acid) but not to the NA1-like viruses (75.8-78.4% nucleotide and 79.7-82.8% amino acid). Although these viruses could not be classified into NA1- and NB-like viruses from the sequence and phylogenetic data of the entire capsid gene, all the Korean BECs clustered together on a branch separate from the other known BECs. These results show that these BEC infections are endemic in diarrheic calves in South Korea. The infecting strains are genetically closer to the NB-like viruses but have a distinct evolutionary pathway.