Survival and behavioural responses of cool and warm water fish sedated with AQUI‐S®20E (10% eugenol) at high loading densities

This study evaluated the effects of AQUI‐S^®20E (10% eugenol) sedation on the survival and behaviour of yellow perch Perca flavescens (Mitchill) and Nile tilapia Oreochromis niloticus L. held in high loading densities. Fish were held in 0–300 mg L^?1 AQUI‐S^®20E (0–30 mg L^?1 eugenol) for up to 10 h in static tanks. At 17°C, yellow perch held in 200 and 300 mg L^?1 AQUI‐S^®20E were lightly sedated for up to 7 h. Yellow perch at 200 and 300 mg L^?1 AQUI‐S^®20E also had >95% mean survival 7‐days post exposure using loading densities up to 360 g L^?1. Nile tilapia were only sedated for ≤3 h in concentrations up to 300 mg L^?1 at 22°C and had >90% mean survival at loading densities ≤480 g L^?1. Ammonia in tanks increased significantly as loading density increased, but treatment with AQUI–S^®20E did not reduce ammonia accumulation. Results suggest that AQUI–S^®20E was effective to sedate yellow perch and Nile tilapia at high loading densities, but sedation varied with loading density and species.     

Effect of cortisol on the metabolism of 17-hydroxyprogesterone by Arctic charr and rainbow trout embryos

The effect of cortisol on the in vitro metabolism of [³H]17-hydroxyprogesterone ([³H]17OHP) was studied during embryonic development of Arctic charr (Salvelinus alpinus) and rainbow trout (Oncorhynchus mykiss). In the absence of cortisol, rainbow trout embryos metabolized [³H]17OHP largely to androstenedione (A₄) and androstenetrione (11-KA) with a minor conversion to 17,20ß-dihydroxy-4-pregnen-3-one (17,20P). In the presence of cortisol, this biosynthesis was inhibited. On the other hand, cortisol had no apparent inhibitory effect on the nature of metabolism of [³H]17OHP by Arctic charr embryos. In these embryos [³H]17OHP was metabolized mainly to 17,20P with a minor conversion to A₄ and without the formation of 11-KA that was seen in rainbow trout.When incubated in the presence of [³H]cortisol both Arctic charr and rainbow trout embryos produced 11ß-hydroxyandrostenedione (11ß-OHA) as the major metabolite, with a minor conversion to an unknown steroid. The catabolism of the cortisol by salmonid embryos may reflect the ability of the embryo to inactivate or detoxify cortisol to protect itself from the adverse effects of this biologically potent steroid hormone The study indicates the existence of species-specific differences in the nature of metabolism of [³H]17OHP and the inhibitory effect of cortisol on this metabolism.     

Enhancement of gilthead seabream (Sparus aurata) larval growth by dietary vitamin E in relation to two different levels of essential fatty acids

The objective of this study was to determine the effect of dietary vitamin E on gilthead seabream (Sparus aurata) growth and survival, at two different highly unsaturated fatty acids (HUFAs) levels. Eighteen days old gilthead seabream larvae were fed four formulated experimental diets combining two different dietary levels of HUFAs (M: medium 2.5 + 1.5, DHA + EPA, H: high 5 + 2.5 DHA + EPA g per 100 g) with two different levels of vitamin E (M: medium 540 mg kg^?1, H: high 2900 mg kg^?1): MM, MH, HM, HH (HUFA/vitamin E). After 2‐week feeding trial, the average survival rate was 52.6% and there were no significant differences found among treatments. Increase in vitamin E up to high level markedly improved larval growth, particularly when dietary HUFA levels were lower, suggesting a higher protection value when these fatty acids are more limiting. At medium dietary HUFA levels, increase in vitamin E from medium to high level enhanced larval growth performance in terms of total length. Moreover, increase in vit E enhanced HUFAs content in the larval polar lipids denoting the anti‐oxidative effect of vitamin E.     

Requirement of vitamin E of growing sea cucumber Apostichopus japonicus Selenka

This feeding trial was conducted to determine the vitamin E requirement of growing sea cucumber Apostichopus japonicus Selenka. Six isonitrogenous and isoenergetic experimental diets were formulated to contain graded levels of vitamin E (6.7, 81.2, 159.3, 237.8, 314.6, 395.9 mg/kg diet). Each diet was assigned randomly to 30 growing sea cucumber with initial body weight 15.43 g in triplicates for 8 weeks. Survival rate was not affected by dietary vitamin E; meanwhile, both the weight gain (WG) and specific growth rate were presented the trend of increasing first and then kept stable. With the increasing of dietary vitamin E, crude lipid content of body wall was evaluated firstly and dropped afterwards. When dietary vitamin E contents were lower than 159.3 mg/kg, vitamin E contents of body wall were increased by dietary vitamin E levels, but there were no more differences when dietary vitamin E higher than 159.3 mg/kg. There were minor effects on digestive enzymes of intestine by dietary vitamin E. Contents of malondialdehyde were decreased, while the total superoxide dismutase activity was increased first and then decreased with the increasing of dietary vitamin E. Activities of intestinal alkaline phosphatase were increased, and glutamic oxaloacetic transaminase were decreased first and then increased with the increasing of dietary vitamin E. In conclusion, analysis by a linear regression equation of WG or vitamin E contents in body wall indicated that the optimum requirement of vitamin E for growing sea cucumber (initial body weight 15.43 g) was 165.2–187.2 mg/kg diet.     

维生素E对绵羊鲜精及冻精精液品质的影响

日粮中添加维生素E可以提高绵羊鲜精的活率 ,对照组和试验组的活率分别为 0 72± 0 0 7和 0 78± 0 0 6(P <0 0 5 ) ,显著改善鲜精精液品质。采用两步稀释法在绵羊冷冻精液稀释液中添加维生素E ,可以极显著降低冷冻对精子顶体的冷刺激损害程度 ,试验组的活率 ( 0 43 5± 0 0 2 0 )极显著高于对照组 ( 0 3 65± 0 0 2 6) (P <0 0 1) ,精子顶体的总异常率试验组 ( 3 3 72 % )极显著低于对照组 ( 4 4 3 5 % ) (P <0 0 1) ,其中试验组顶体膨胀率和脱落率与对照组分别为 1 2 8%±0 5 8%、2 3 0 8%± 1 45 %与 2 68%± 0 5 9%、2 8 96%± 3 14 %。冷冻精液品质显著改善。     

黄芩抗鸡大肠杆菌作用的研究

通过体外和体内两种方法研究黄芩抗鸡大肠杆菌作用.通过体外抑菌作用测定黄芩水煎液对鸡大肠杆菌的最小抑菌浓度（MIC）为2.5g/ml;体内抑菌作用通过对7日龄雏鸡的攻毒与治疗试验来研究,体内治疗药物浓度5g/ml可使90%以上雏鸡获得保护,10g/ml可使100%雏鸡获得保护.以上说明黄芩可以对抗鸡大肠杆菌,可以防治鸡的大肠杆菌病.     

毒害艾美耳球虫(Eimeria necatrix)广东株微线蛋白-2基因在大肠杆菌的表达

根据克隆的毒害艾美耳球虫(Eimeria necatrix)广东株微线蛋白-2基因(EnMIC-2(Gd))的cDNA序列设计特异性引物，用PCR方法扩增其阅读框架(ORF)后，克隆至质粒表达载体pET-32a( )，成功构建了重组表达质粒pET-32a( )-EnMIC-2。用CaCl2法将其转化至宿主细菌E.cliBL21(DE3)，并用IPTG成功诱导了EnMIC-2重组抗原在大肠杆菌表达。表达的重组蛋白约占菌体总蛋白的10．8％，其相对分子质量约为55000。重组蛋白经SDS-AGE分析后，用E．necatrix(广东株)感染鸡的高免血清进行Western Blotting分析，结果为阳性。     

真鲷虹彩病毒自然感染杂交石斑鱼“褐龙斑”的组织病理分析

褐龙斑是雌性褐石斑鱼(Epinephelus bruneus)和雄性鞍带石斑鱼(E. lanceolatus)杂交产生的子代。作为杂交石斑鱼的新品种,国内外尚没有褐龙斑疾病的报道。2017年7月,某养殖场褐龙斑出现急性死亡,10 d内累积死亡率高达80%。现场调查发现,病鱼外观无明显异常,但反应迟钝,伏底死亡。临床检查和剖检可见脾和肾严重肿大、易碎。组织病理切片观察发现,各组织中存在数量不等的嗜碱性、细胞质均一、直径为10~15 µm的肿大细胞。超薄组织切片中发现,肿大细胞胞质内存在大量直径为130~150 nm的虹彩病毒样颗粒。使用特异性的PCR引物,从病鱼脾、头肾等组织中均检测到真鲷虹彩病毒(Red seabream iridovirus, RSIV)的高强度感染。测定了该病毒主要衣壳蛋白(Major capsid protein, MCP)基因1362 bp的全长编码区,构建了19种(株)虹彩病毒系统发育树,结果显示,该病毒属于虹彩病毒科肿大细胞病毒属RSIV类群。本研究首次描述了褐龙斑虹彩病毒病的组织病理特征,揭示了褐龙斑是RSIV新的敏感宿主,为杂交石斑鱼病毒病的诊断与防治提供了重要的参考依据。     

Effect of vitamin E on spermatophore regeneration and quality of pond‐reared,black tiger shrimp (Penaeus monodon)

The objective of the present work was to evaluate the effects of different levels of vitamin E in feed on the spermatophore regeneration and quality of male Penaeus monodon. The experiment was carried out with the four following treatments: the basal diet no added vitamin E, the diet added 200, 600 and 1,000 mg/kg respectively. Spermatophore regeneration and quality were evaluated by spermatophore weight, sperm count and spermatophore absence rates, which male P. monodon were extruded spermatophore for feeding 20 and 40 days. In the experiment, the weight of the twice regenerated spermatophore of the males added to the vitamin E group was higher than that of the untreated control group. The weight of the first regenerated spermatophore with the addition of 1,000 mg/kg group was the highest and significantly higher than the control group (p < .05), but there was no significant difference among the three groups with different levels of vitamin E. The weight of the second regenerated spermatophore with the addition of 600 mg/kg group was the highest, followed by 1,000 mg/kg group, both of which were higher than the control group and the addition of 200 mg/kg group. Within the same group, the regeneration spermatophore weight showed overall upward trend as the feeding time, twice regenerate experiment spermatophore weight with added to the vitamin E groups were significantly higher than the initial value (p < .05), but three spermatophore weight of male shrimp at the control group had no significant difference. The sperm quantity and the percentage of normal sperm of the twice regenerated spermatophore of the males with added to the vitamin E group was higher than that of the untreated control group, and those of the addition of 200 mg/kg group was significantly higher than that of control group (p < .05). The total number of sperm and the percentage of living sperm of male shrimp in the experimental group decreased with the increase of vitamin E in the feed. Within the same group, the total number of sperm and the percentage of living sperm of male shrimp with added to the vitamin E groups showed overall upward trend as the feeding time and were significantly higher than the initial value (p < .05), but the control group was slightly down and had no significant difference. Comprehensive sperm weight, sperm quantity and living sperm percentage of three indicators, that adding 200 mg/kg of vitamin E in feed could effectively promote the spermatophore regeneration in the male P. monodon and improve the sperm quantity. The experimental results provide a scientific basis for the breeding of P. monodon.     

温室大棚无线温湿度监测装置的设计

设计了一种无线温度、湿度监测装置,该装置通过一体化温湿度传感器SHT11对温室大棚内温度、湿度进行采集,然后将采集到的数据按照协议通过无线模块发送出去;接收方接收到数据后解包,计算出温度、湿度值并显示在液晶屏上。该系统发射部分以AT89C2051为内核,包括温度、湿度采集模块和无线发射模块;接收部分以AT89S52为核心,将无线接收,液晶显示等模块结合起来,通过软、硬件抗干扰处理,设计出的实用、小型的无线监测温度、湿度装置可广泛应用到温室、粮仓等场合中。