Effects of acute cold exposure on oxidative balance and total antioxidant capacity in juvenile Chinese soft‐shelled turtle,Pelodiscus sinensis

Acute cold exposure may disturb the physiological homeostasis of the body in ectotherms. To date, there has been no information on the effects of cold exposure on homeostasis of reactive oxygen species (ROS) or antioxidant defense response in the Chinese soft‐shelled turtle, Pelodiscus sinensis. In this study, P. sinensis juveniles were acclimated at 28 °C, transferred to 8 °C as cold exposure for 12 h, then moved back to 28 °C rewarming for 24 h. We measured the ROS level and total antioxidant capacity (TAC) in the brain, liver, kidney and spleen at 2 and 12 h cold exposure, and at the end of the rewarming period. Malonaldehyde (MDA) and carbonyl protein were used as markers of oxidative damage. Turtles being maintained simultaneously at 28 °C were used as the control group. Cold exposure did not disturb the ROS balance in all 4 tissues, while rewarming raised the ROS level in the brain and kidney of P. sinensis. Cold exposure and rewarming decreased the TAC in the brain, liver and spleen but did not change the TAC in the kidney. MDA and carbonyl protein levels did not increase during the treatment, indicating no oxidative damage in all 4 tissues of P. sinensis. Our results indicated that extreme cold exposure did not impact the inner oxidative balance of P. sinensis, but more ROS was produced during rewarming. P. sinensis showed good tolerance to the harsh temperature change through effective protection of its antioxidant defense system to oxidative damage. This study provides basic data on the stress biology of P. sinensis.     

Reproduction in the Rock Hyrax (Procavia Capensis)

Irradiation has adverse effects on reproductive aspects such as spermatogenic cell population and cell malformation, leading to reduced sperm count and non-viable spermatozoa. This has overshadowed possible effects of radiation exposure on biochemical environment throughout the epididymis and the viability of spermatozoa that appeared morphologically normal. The effects of radiation exposure on sperm quality were evaluated through mating trials and assessment of the cauda epididymal sperm motility. Sprague Dawley rats with body mass of 300–400 g were selected at random. Two experimental groups received acute ⁶°Co γ-radiation doses of 3.5 and 6.0 Gy, respectively. Data were collected 2, 7, 14, 21, 28 and 35 days post-irradiation. Each male was housed with a non-irradiated super-ovulated female during mating trials. Cauda epididymal sperm motility was assessed with the CASMA. Hormone analyses were carried through chemiluminescence diagnostic tests to determine the endocrine status. Results suggest that irradiation causes an overproduction of estrogens, which suppresses the hypothalamic-pituitary axis and inhibits LH and FSH secretions. Both LH and FSH deficiencies have negative effects on the testicular index and local reproductive hormones. Elevated estrogen levels influenced the epididymal internal milieu negatively, resulting in rigid, flagella bending sperm tail, impaired progressive movement of the spermatozoa and hence infertility     

兽药环境风险评估研究进展

随着畜禽集约化养殖数量增加,兽药被广泛用于治疗疾病或作为促生长剂添加到动物饲料中,中国2010-2017年兽用抗菌药的销售量从31 500 t增长到56 800 t。兽药的不合理使用、畜禽养殖过程中废弃物处理不当以及药物经过动物机体代谢后以原形药或代谢物随粪尿排出体外是兽药造成环境污染的主要原因。兽药进入环境后发生迁移转化造成了严重危害,包括抗生素耐药菌或耐药基因的产生、兽药在动植物源性食品和饮用水中的暴露间接影响人类健康、对非靶标动物的生态毒性等。作者就兽药在环境中的暴露、转归及对生态环境的主要影响进行了论述,并对药物的环境风险评估的重要性进行了阐述,针对降低兽药环境风险的措施提出了建议,以引起人们对兽药环境风险评估的关注和重视。     

不同日粮蛋白质水平对乌金猪肉品质的影响

旨在研究日粮不同蛋白水平对乌金猪肉品质的影响及最优肉品质所需的日粮适宜蛋白水平。选取体质量15kg左右的乌金猪90头,随机分为5组,每组18头,下设3个重复,每个重复6头。试验采用单因子随机分组设计,在体质量为15～30、30～60和60～100kg阶段的日粮蛋白水平分别为最高蛋白水平（HHP,18％、16％和14％）、中高蛋白水平（HMP,17％、15％和13％）、中蛋白水平（MMP,16％、14％和12％）、中低蛋白水平（MLP,15％、13％和11％）和最低蛋白水平（LLP,14％、12％和10％）。各组在不同生长阶段日粮能量、微量元素、氨基酸等水平固定。试验期至100kg体质量,分别在30、60和100kg体质量时屠宰,测定肉品质指标及肌肉营养成分,采用模糊综合评定系统分析并确定最优肉品质日粮适宜蛋白水平。结果表明,日粮不同蛋白水平对乌金猪不同生长阶段肌肉pH、系水力、剪切力、烹煮损失和滴水损失有明显影响,其中高、中、低蛋白组间差异显著（P〈0．05）,大理石纹评分随蛋白水平的降低而增加,低蛋白组显著高于高蛋白组（P〈0．05）。随着日粮蛋白水平的增加,肌肉中粗蛋白含量提高,在100kg体质量时达显著水平（P〈0．05）;粗脂肪、肌内脂肪和肌苷酸含量降低,不同生长阶段高、中、低能量组间差异显著（P〈0．05或P〈0．01）。以大理石纹、剪切力和滴水损失为评定肉品质的代表指标,通过综合评定确定30、60和100kg体质量时最优肉品质适宜的日粮蛋白水平分别为15．88％、14．13％和11．42％。研究结果为乌金猪的合理饲养和改善肉品质提供了科学依据。     

Selenium Concentrations in Tissues and Eggs of Growing and Laying Chickens Fed Sodium Selenite at Different Levels

Growing and laying chickens were fed graded levels of selenium in the form of sodium selenite. One day old Norwegian bred broiler chickens and 20 weeks old Norwegian bred White Leghorn chickens were divided into 5 groups each and fed a basal diet supplemented with 0, 0.1, 1.0, 3.0 or 6.0 μg Se/g for 6 and 31 weeks, respectively. At the end of the experiments significantly higher concentrations of selenium were found in the groups fed 1.0, 3.0 and 6.0 μg Se/g diet compared to the control group. Correspondingly higher concentrations of selenium were found in egg samples. The increase in egg yolk selenium was much higher than in egg white. Significant correlations were found between the amounts of selenium added to the ration and the selenium concentrations in liver, kidney, breast muscle, egg white, yolk and homogenized egg. There were no differences in body weight gain and egg production between the groups. A possible positive contribution to animal and human health of selenium supplementation of animals’ diet above the required level is discussed.     

野山杏果肉成分分析及对小鼠小肠蠕动作用的研究

考察野山杏干果肉的营养成分及其膳食纤维的润肠通便作用,同时研究用碱处理法从野山杏果肉中提取膳食纤维的最佳工艺条件。研究结果表明,野山杏干果肉含有丰富的膳食纤维（51．84％）和钾、镁、磷、铁、钠等多种矿物质元素及维生素;制备野山杏果肉膳食纤维的最佳工艺条件是碱处理温度为30℃．碱处理时间为60min,碱（NaOH）溶液用量为11mL／g;肠蠕动实验组与模型组相比,中、高剂量对便秘模型小鼠的小肠蠕动和推进作用有显著性差异（P〈0．05）,表明野山杏果肉膳食纤维可明显促进小鼠小肠蠕动,具有润肠通便作用。     

Hepatitis E virus in Cuba: A cross-sectional serological and virological study in pigs and people occupationally exposed to pigs

Surveillance of hepatitis E virus (HEV) in risk groups is an important strategy to monitor its circulation pattern and to timely detect changes thereof. The aims of this cross-sectional study were to estimate the prevalence of HEV infections in pigs and humans from different regions of the country, to identify risk factors for increasing anti-HEV IgG prevalence and to characterize HEV strains. The presence of anti-HEV antibodies was assessed by commercial ELISA in serum samples from the general population, farm and slaughterhouse employees, as well as pigs sampled in the three regions of Cuba from February to September 2016. Overall, individuals with occupational exposure to swine or swine products (70/248, 28.2%) were 4 times more likely to be seropositive compared to the general population (25/285, 8.7%; OR: 4.18; p < .001). Within the risk group, risk factors included age, number of years working in a professional activity with direct exposure to swine, geographic region and distance between residence and closest professional swine setting, while wearing gloves had a protective effect. Prevalence of total anti-HEV antibodies in swine was 88.2% (165/187) and HEV RNA was detected by real-time RT-PCR in 9.2% (16/173) swine stools. All HEV strains sequenced clustered within genotype 3. Some strains clearly belonged to subtype 3a, while another group of strains was related with subtypes 3b and 3 k but partial HEV sequences did not allow unequivocal subtype assignment. These findings suggest that the high HEV exposure in Cuban individuals with swine-related occupations could be due to enzootic HEV in certain regions, direct contact with infectious animals or their products as well as environmental contamination.     

RADIATION EXPOSURE DURING EQUINE RADIOGRAPHY

All personnel present in the X-ray examination room during equine radiography were monitored using low energy direct reading ionization chambers (pockets dosimeters) worn outside the lead apron at neck level. The individuals' task and dosimeter readings were recorded after each examination. Average doses ranged from 0 to 6 mrad per study. The greatest exposures were associated with radiography of the shoulder and averaged less than 4 mrad. The individual extending the horse's limb was at greatest risk although the individual holding the horse's halter and the one making the X-ray exposure received similar exposures.
A survey of the overhead tube assembly used for some of the X-ray examinations also was performed. Meter readings obtained indicated an asymetric dose distribution around the tube assembly, with the highest dose occurring on the side to which the exposure cord was attached.
Although the exposures observed were within acceptable limits for occupational workers, we have altered our protocol and no longer radiograph the equine shoulder unless the horse is anesthetized. Continued use of the pocket dosimeters and maintenance of a case record of radiation exposure appears to make the technologists more aware of radiation hazards.     

反刍动物围产期能量负平衡的调控研究进展

在奶牛围产期,许多奶牛因能量负平衡(NEB)无法适应代谢、内分泌和生理的巨大变化,引发酮病和脂肪肝,影响奶牛产后恢复,造成严重的经济损失.奶牛分娩、产犊的应激性大,产奶量增长迅速,采食量降低,饲养中能量供应不足是此阶段存在的主要问题.为获得更高品质的肉制品以及更高的养殖收益,文章针对调控围产期NEB展开综述,以期为生产...     

Physiological effects of different Cd concentrations on maize root architecture and classification北大核心CSCD

In this research, a hydroponics experiment was conducted to apply different concentrations of cadmium (Cd) (0, 5, 10, 25, 50, 100, 200 μmol·L-1) to maize seedlings with two leaves and one new leaf, in order to explore the effects of the different Cd concentrations on the maize seedling growth, Cd absorption kinetics and root morphology and classification. After 5 days of Cd stress, the maize seedings were sampled, the plant height, main root length, aboveground and underground biomass, root architecture, Cd content and photosynthesis and related parameters were measured. It was found that with increasing Cd stress, the plant height, main root length, biomass and tolerance index of shoots and roots, total root length, root surface area, root volume, root forks and root tips all decreased significantly; Root average diameter and root:shoot increased significantly (P<0.05). Meanwhile root parameters (root length, root surface area and root volume) of root diameter classes designated Ⅰ-Ⅲ (0-1.5 mm) showed a decreasing trend, which had a significant (P<0.05) negative correlation with root Cd concentration. The proportion of root length, root surface area and root volume with diameter between 0-0.5 mm showed a downward trend under Cd stress. Under Cd stress, Cd concentration and accumulation in underground and aboveground parts of maize seedlings increased significantly, chlorophyll content decreased, and photosynthesis was inhibited. This study has shown that Cd affected root development mainly by inhibiting the growth and morphology of fine roots, and inhibited photosynthesis, elongation and biomass accumulation of the aboveground and underground parts of the maize seedings. © 2022, Editorial Office of Acta Prataculturae Sinica. All rights reserved.