Effect of dietary organic microminerals on starter pig performance, tissue mineral concentrations, and liver and plasma enzyme activities

Weanling pigs (n = 160) were used to evaluate dietary essential microminerals (Cu, Fe, Mn, Se, and Zn) on performance, tissue minerals, and liver and plasma enzymatic activities during a 35-d postweaning period. A randomized complete block design with 5 treatments and 8 replicates was used in this study. Organic microminerals were added to complex nursery diets at 0 (basal), 50, 100, or 150% of the requirements of microminerals listed by the 1998 NRC. A fifth treatment contained inorganic microminerals at 100% NRC and served as the positive control. Pigs were bled at intervals with hemoglobin (Hb), hematocrit (Hct), glutathione peroxidase, and ceruloplasmin activities determined. Six pigs at weaning and 1 pig per pen at d 35 were killed, and the liver, heart, loin, kidney, pancreas, and the frontal lobe of the brain were collected for micromineral analysis. The liver was frozen in liquid N for determination of enzymatic activities. The analyzed innate microminerals in the basal diet met the NRC requirement for Cu and Mn but not Fe, Se, and Zn. Performance was not affected from 0 to 10 d postweaning, but when microminerals were added to diets, ADG, ADFI, and G:F improved (P < 0.01) from 10 to 35 d and for the overall 35-d period. Pigs fed the basal diet exhibited parakeratosis-like skin lesions, whereas those fed the supplemental microminerals did not. This skin condition was corrected after a diet with the added microminerals was fed. When the basal diet was fed, Hb and Hct declined, but supplemental microminerals increased Hb and Hct values. Liver catalase activity increased (P < 0.01) when microminerals were fed. The Mn superoxide dismutase activity tended to decline quadratically (P = 0.06) when supplemental microminerals were fed above that of the basal diet. Liver plasma glutathione peroxidase activities were greater (P < 0.01) when dietary organic and inorganic micromineral were fed. Liver concentrations of microminerals increased linearly (P < 0.01) as dietary microminerals increased, indicating that the liver was the primary storage organ. Micromineral tissue concentrations were least in pigs fed the basal diet and increased (quadratic, P < 0.01) to the 50% level of organic microminerals in the various tissues collected. The results indicated that innate microminerals, Cu and Mn, from a complex nursery diet may meet the micromineral needs of the weaned pig, but the need for Fe, Se, or Zn was not met by the basal diet.     

Effects of intravenous lidocaine on the minimum alveolar concentration of isoflurane in cats

Lidocaine has been reported to decrease the minimum alveolar concentration (MAC) of inhalation anesthetics in several species and has been used clinically to reduce the requirements for other anesthetic drugs. This study examined the effects of intravenous lidocaine on isoflurane MAC in cats. Six cats were studied. In experiment 1, the MAC of isoflurane was determined. An intravenous bolus of lidocaine 2 mg kg^–1 was then administrated and venous plasma lidocaine concentrations measured to determine pharmacokinetic values. In experiment 2, lidocaine was administered to achieve target plasma concentrations between 1 and 11 μg mL^–1 and the MAC of isoflurane was determined in triplicate at each lidocaine plasma concentration, using the tail‐clamp method. End‐tidal isoflurane concentration was determined using a calibrated infrared analyzer. Systolic blood pressure (Doppler), SpO2 and end‐tidal PCO2 (calibrated Raman spectrometer) were measured prior to each MAC determination. Body temperature was maintained between 38.5 and 39.5 °C by supplying external heat as needed. MAC values at the different lidocaine plasma concentrations were analyzed by a repeated measures ANOVA , using the Huynh–Feldt correction. The MAC of isoflurane in these cats was 2.21 ± 0.17. For the target concentrations of 1, 3, 5, 7, 9, and 11 μg mL^–1, the actual lidocaine plasma concentrations was 1.06 ± 0.12, 2.83 ±0.39, 4.93 ± 0.64, 6.86 ± 0.97, 8.86 ± 2.10, and 9.84 ± 1.34 μg mL^–1, respectively. At these target concentrations, the MAC of isoflurane was 2.14 ± 0.14, 1.88 ± 0.18, 1.66 ± 0.16, 1.47 ±0.13, 1.33 ± 0.23, and 1.06 ± 0.19%, respectively. Lidocaine, at target plasma concentrations of 1, 3, 5, 7, 9, and 11 μg mL^–1, linearly decreased isoflurane MAC by –6 to 6, 7 to 28, 19 to 35, 28 to 45, 29 to 53, and 44 to 59%, respectively. Lidocaine significantly dose‐dependently and linearly decreases the requirements for isoflurane in cats. No ceiling effect was observed within the range of plasma concentrations studied.     

水稻突变群体的构建及功能基因组学

随着水稻基因组全序列的测定完成，功能基因组学已成为重点研究内容。功能基因组学主要研究生物有机体内各基因的生物学功能进而了解所有基因如何协调发挥作用完成一系列的生长发育过程。目前已经发展了多种分析鉴定基因功能的方法，其中最直接最有效的方法是构建饱和的基因突变群体，通过突变体分析鉴定基因功能。本文主要阐述了各种构建方法及其优缺点以及在功能基因分离鉴定上的应用。自发突变的频率极低，且自发突变基因的分离难度比较大，只能作为突变群体构建的辅助方法。利用EMS等化学诱变剂可以在短时间内构建大量点突变群体，并可用TILLING进行突变检测，但多位点的点突变使突变表型难以鉴定。由快中子等物理诱变也可以在短时间内构建大量缺失突变体，且可用Ddeteagene系统进行检测；但多基因缺失、多位点缺失和内含子缺失等使突变表型的分析可能无法进行。利用T—DNA、转座子和反转录转座子等构建插入突变体已经成为突变库构建的主要方法。T—DNA插入已成功应用于水稻大规模突变体的构建，但只限于转基因效率较高的品种；T—DNA在基因组中整合的复杂性以及转基因过程中由组织培养等引发的突变等，增加了突变体表型和分子分析的难度。Tos17是目前应用最为成功的反转录转座子，但多拷贝的插入使突变体的表型鉴定和分子鉴定较为困难，因为只有10％左右的突变性状是由Tos17插入引起的。理论上，Ac／Ds双因子系统是目前最理想的水稻插入突变库构建体系，Ds的单拷贝插入，大大方便了突变体的表型分析和分子鉴定；Ds的回复突变，可以验证突变表型是否由Ds插入引起；但在血转座酶驱动下Ds可能发生的多次跳动所形成的痕迹(footprint)也可能影响突变表型的分析。RNAi可以有效地使目标基因沉默，但并不是所有基因均可被RNAi沉默；对多因一效基因或同源性较高的基因家族，RNAi会同时作用这些基因，沉默表型很难鉴定。可见，每一种方法都有各自的优缺点，但不同的方法是可以互补的，通过各种方法是能够构建成理想的水稻突变库的。     

Factors determining the performance of synthetics in Vicia faba L. 1. Heterogeneity,heterozygosity, and degree of cross-fertilization

Summary The relative performance of synthetic varieties in faba beans (Vicia faba L.) as compared with line varieties is the result of the joint effect of several factors. Factors investigated in the present study were (1) effects of heterogeneity and (2) heterozygosity on agronomic performance, (3) genetic variance for the degree of cross-fertilization among inbred lines and (4) genetic variance among homozygous and heterozygous genotypes for yield. The evaluation was based on multilocational trials in Germany with 36 inbred lines and derived entries with contrasting population structure (levels of heterozygosity and heterogeneity). When inbred lines and F₁-hybrids are included in the same mixture of genotypes, the resulting heterogeneity had a positive effect on yield. Relative mid-parent heterosis for yield was between 33% and 51%. The average degree of cross-fertilization was 53.5%, and its genetic standard deviation was 8.3%. The estimates for genetic standard deviation for yield among inbred lines were between 3.4 q/ha and 5.3 q/ha. The highest yielding synthetic variety is expected to outyield markedly the highest yielding line.     

Cardiovascular effects of propofol alone and in combination with ketamine for total intravenous anesthesia in healthy cats

This study was designed to compare the cardiovascular effects of equipotent maintenance of anesthetic doses (determined in a previous study) of propofol and propofol/ketamine, administered with and without noxious stimulation. Six healthy adult cats were anesthetized with propofol (loading dose 6.6 mg kg^?1, infusion 0.22 mg kg^?1 minute^?1), and instrumented to allow determination of blood gas and acid–base balance and measurement of blood pressures and cardiac output. The propofol infusion was continued for a further 60 minutes after which measurements were taken prior to and during application of a noxious stimulus. The propofol infusion was decreased to 0.14 mg kg^?1 minute^?1, and ketamine (loading dose 2 mg kg^?1, infusion 23 µg kg minute^?1) was administered. After a further 60 minutes, measurements were again taken prior to and during application of a noxious stimulus. The data were analyzed, using several Repeated Measures anova (first, ketamine/propofol and noxious stimulation were each treated as within‐subject factors; secondly, the levels of these two factors were combined into a single within‐subject factor). Mean arterial pressure, CVP, PAOP, SI, CI, SVRI, PVRI, oxygen delivery index, oxygen consumption index, oxygen utilization ratio, PvO₂, pHa, PaCO₂, bicarbonate concentration, and BD values collected during propofol administration were not changed by addition of ketamine and reduction of propofol concentration or by application of a noxious stimulus under propofol alone. Application of a noxious stimulus under propofol alone did, however, significantly increase HR and PaO₂, and these responses were not blunted by the addition of ketamine. Compared with propofol, administration of ketamine and reduction of propofol concentration significantly increased PAP and venous admixture, and significantly decreased PaO₂. Although application of a noxious stimulus to cats under propofol alone did not significantly change CVP, SI, CI, PVRI, oxygen delivery index, and oxygen consumption index, significant differences were found in these variables between propofol and propofol/ketamine. In conclusion, propofol alone provided cardiopulmonary stability; addition of ketamine did not improve hemodynamics but did decrease oxygenation.     

Strong fisheries management and governance positively impact ecosystem status

Fisheries have had major negative impacts on marine ecosystems, and effective fisheries management and governance are needed to achieve sustainable fisheries, biodiversity conservation goals and thus good ecosystem status. To date, the IndiSeas programme (Indicators for the Seas) has focussed on assessing the ecological impacts of fishing at the ecosystem scale using ecological indicators. Here, we explore fisheries ‘Management Effectiveness’ and ‘Governance Quality’ and relate this to ecosystem health and status. We developed a dedicated expert survey, focused at the ecosystem level, with a series of questions addressing aspects of management and governance, from an ecosystem‐based perspective, using objective and evidence‐based criteria. The survey was completed by ecosystem experts (managers and scientists) and results analysed using ranking and multivariate methods. Results were further examined for selected ecosystems, using expert knowledge, to explore the overall findings in greater depth. Higher scores for ‘Management Effectiveness’ and ‘Governance Quality’ were significantly and positively related to ecosystems with better ecological status. Key factors that point to success in delivering fisheries and conservation objectives were as follows: the use of reference points for management, frequent review of stock assessments, whether Illegal, Unreported and Unregulated (IUU) catches were being accounted for and addressed, and the inclusion of stakeholders. Additionally, we found that the implementation of a long‐term management plan, including economic and social dimensions of fisheries in exploited ecosystems, was a key factor in successful, sustainable fisheries management. Our results support the thesis that good ecosystem‐based management and governance, sustainable fisheries and healthy ecosystems go together.     

Natriuretic peptide system regulation in granulosa cells during follicle deviation and ovulation in cattle

Natriuretic peptides (NPs) are known to regulate reproductive events in polyovulatory species, but their function and regulation in monovulatory species remain to be fully characterized. Using a well‐established in vivo model, we found that bovine granulosa cells from follicles near the deviation stage express mRNA for the three NP receptors (NPR1, NPR2 and NPR3), but not for NP precursors (NPPA, NPPB and NPPC). The abundance of NPR3 mRNA was higher in dominant compared to subordinate follicles at the expected time of follicular deviation. After deviation, mRNA for all NP receptors was significantly more abundant in the dominant follicle. Intrafollicular inhibition of oestrogen receptors downregulated NPR1 mRNA in dominant follicles. In granulosa cells from preovulatory follicles, NPPC mRNA increased at 3 and 6 h after systemic GnRH treatment, but decreased at 12 and 24 h to similar levels observed in samples collected at 0 h. After GnRH treatment, NPR1 mRNA was upregulated at 24 h, NPR3 mRNA gradually decreased after 3 h, while NPR2 mRNA was not regulated. The mRNA expression of the enzyme FURIN increased at 24 h after GnRH treatment. These findings revealed that the expression of mRNA encoding important components of the NP system is regulated in bovine granulosa cells during follicular deviation and in response to GnRH treatment, which suggests a role of NP system in the modulation of these processes in monovulatory species.     

Chronic hypertrophic pyloric gastropathy in 14 dogs

SUMMARY Ten mate and 4 female dogs with chronic hypertrophic pyloric gastropathy were seen at the Sydney University Veterinary Teaching Hospital in the period 1982–88. The most commonly affected breeds were the Shihtzu and Maltese. The mean age was 8.2 yr and the mean body weight 6.5 kg. The most common clinical signs were vomiting, weight loss, polydipsia and depression. Hypokalaemia was present in 11 of 12 dogs examined and hypochloraemia in 10 of 11 dogs examined. Five of the six dogs that had blood gases measured were found to have a metabolic alkalosis. Surgery was performed on 13 dogs; pyloromyotomy 7, pyloroplasty 4, gastroduodenostomy 2. There was a recurrence of symptoms in one pyloromyotomy dog, and fatal ulceration and perforation of the cardia occurred in one pyloroplasty case. The remaining 11 dogs had a mean known symptom-free survival time of 20 mo. This study confirms the preponderance of affected males, identifies electrolyte and blood gas disturbances as significant complications of chronic hypertrophic pyloric gastropathy, and suggests that relatively minor surgery (pyloromyotomy) may have a place in the treatment of a selected subgroup of cases.