Application of an electronic nose to predict total volatile bases in capelin (Mallotus villosus) for fishmeal production

An electronic nose was used as a rapid technique to monitor changes in the headspace gas above capelin (Mallotus villosus) during storage at 0 and 5 degrees C. At both temperatures, refrigeration was compared with an ice/seawater cooling system. At 5 degrees C, the effect of added 0.2% acetic acid was also tested. Electronic nose measurements were compared to measurements of total volatile bases (TVB), gas chromatography of volatile compounds, and sensory analysis. TVB analysis indicated less spoilage in seawater/ice systems than in refrigeration, but the other measurements indicated more spoilage in the seawater system compared to refrigeration. The possibility of using only a few sensors in the electronic nose to predict TVB was studied using partial least squares regression and a saturated generalized linear model. The results reported herein indicate that rapid electronic nose measurements, which require no sample preparation, can be used to predict the TVB value of the raw material stored under different conditions.     

Analysis of a site x year experiment with timothy polycross progeny

Summary Results from a cooperative breeding programme with timothy for the northern areas of Scandinavia are presented. The main aim of the programme was to identify genotypes for synthetic populations that are high yielding, adapted over the whole area and stable over years. A polycross comprising 12 genotypes from each of five sites within the region was formed. The subsequent 60 half-sib families and four reference varieties were then compared under sward conditions at the same sites. The trials lasted for three years and results for total dry matter yields are presented.Significant differences in yield between lines were found. There were also significant two and three factor interactions between lines, sites and years. A new two-step procedure is presented to select the genotypes to make up a synthetic variety. Firstly, a superiority measure (Q-value) is used to select a group of genotypes that are high yielding and stable over sites and years. Secondly, the GxE part of the Q-value is split into two terms. One measures adaptation to predictable environmental conditions. The other one measures stability to unpredictable changes in the environment. A plot of these two measures provides a tool for discarding unstable or poorly adapted genotypes. The statistical properties of the selection parameters are discussed.     

Loquat as a crop model for successful deficit irrigation

During three consecutive seasons, two different deficit irrigation strategies were compared with control fully irrigated trees regarding their capacity to induce early bloom and harvest in “Algerie” loquat. The first strategy, a continuous deficit irrigation strategy, consisted in a uniform reduction of 20% water needs through the entire season; the second strategy, a regulated deficit irrigation approach, while accounting for the same global reduction of 20% loquat water needs, concentrated water shortages after harvest from mid-May through the end of August. Regulated deficit irrigation resulted more successful. Postharvest regulated deficit irrigation advanced full bloom 10–20 days depending on the season. Such enhancement led to more precocious and valuable yield, with an average increase of fruit value of 0.21 € kg⁻¹. The effects of continuous deficit irrigation were less noticeable and average fruit value was increased 0.08 € kg⁻¹. Yield and fruit quality were not affected for the different deficit irrigation strategies. Water savings established around 1450 m³ ha⁻¹ year⁻¹. Deficit irrigation rose water use efficiency up to more than a 40%.     

Body weight of newborn and suckling piglets affects their intestinal gene expression

Modern hyperprolific sows must deal with large litters (16–20 piglets) which reduce piglet birthweight with a concomitant increase in the proportion of small and intrauterine growth retarded piglets. However, larger litters do not only have a greater variation of piglet weights, but also a greater variation in colostrum and milk consumption within the litter. To further understand the impact that body weight has on piglets, the present study aimed to evaluate the degree of physiological weakness of the smallest piglets at birth and during the suckling period (20 d) compared to their middle-weight littermates through their jejunal gene expression. At birth, light piglets showed a downregulation of genes related to immune response (FAXDC2, HSPB1, PPARGC1α), antioxidant enzymes (SOD2m), digestive enzymes (ANPEP, IDO1, SI), and nutrient transporter (SLC39A4) (P < 0.05) but also a tendency for a higher mRNA expression of GBP1 (inflammatory regulator) and HSD11β1 (stress hormone) genes compared to their heavier littermates (P < 0.10). Excluding HSD11β1 gene, all these intestinal gene expression differences initially observed at birth between light and middle-weight piglets were stabilized at the end of the suckling period, when others appeared. Genes involved in barrier function (CLDN1), pro-inflammatory response (CXCL2, IL6, IDO1), and stress hormone signaling (HSD11β1) over-expressed compared to their middle-weight littermates (P < 0.05). In conclusion, at birth and at the end of suckling period, light body weight piglets seem to have a compromised gene expression and therefore impaired nutrient absorption, immune and stress responses compared to their heavier littermates.     

猪脐静脉血管内皮细胞的分离及体外培养研究

为建立一种操作简单并且能获得大量猪血管内皮细胞的分离培养方法,本研究采集新生健康长白猪脐带,取其脐静脉血管,灌注0.1%的Ⅰ型胶原酶,于37℃水浴消化10 min后收集内皮细胞,培养于含20%胎牛血清的M199培养基中,长满单层后用胰酶消化传代培养。并对培养的细胞形态学、相关抗原和其他特征以及对病毒的易感性进行鉴定。结果表明,Ⅰ型胶原酶消化后可获得大量内皮细胞,细胞培养后的形态学观察显示细胞贴壁生长良好,呈典型的铺路石状排列;第Ⅷ因子相关抗原和细胞摄取乙酰化低密度脂蛋白均呈阳性,内皮细胞比率可高达100%。传3代后的生长曲线显示细胞传代后延迟期小于1 d,对数生长期约3 d,第5 d进入平台期,第7 d开始脱落死亡。病毒感染试验表明所获得的内皮细胞对猪瘟病毒高度易感,病毒生长与常用的PK-15没有区别。上述研究结果表明本研究建立的血管内皮细胞分离培养方法简便有效,为大量制备原代血管内皮细胞提供了可靠的方法。     

Dual-label time-resolved fluoroimmunoassay for simultaneous quantification of haptoglobin and C-reactive protein in meat juice from pigs

A new method was developed to simultaneously measure 2 acute-phase proteins (APPs) by time-resolved immunofluorometry. The assay, based on double-label quantification of haptoglobin (Hp) and C-reactive protein (CRP) in meat juice samples from pigs, was constructed by use of a combination of europium and samarium chelate lanthanides as labels. Meat juice samples from 154 pigs were used for analytic and clinical validation of the assay through determination of precision, accuracy, limit of detection, and quantification. The analytic performance of the assay was satisfactory, with good intra-assay and interassay precision and accuracy. The levels of Hp and CRP were increased in the meat juice samples of diseased animals compared with healthy ones. According to the results, higher sensitivity could be achieved if the cut-off values of both proteins were taken into account for clinical relevance rather than used individually. Since the dual assay saved both time and sample, it could be used as a rapid and sensitive screening test in porcine production.     

Limnological changes in a sub‐tropical shallow hypertrophic lake during its restoration: two years of a whole‐lake experiment

1. Lake Rodó is a turbid system, a condition attributed to algal biomass. The proximal source of the eutrophication was stormwater discharges from an ill‐defined urban area. This paper describes an attempt to restore the water quality of Lake Rodó, the first time this has been done in Uruguay. In spring 1996 it was drained, sediments were removed and stream inputs were diverted. Groundwater was used to re‐fill the lake. Due to its high nutrient concentration a re‐circulation system was designed, pumping water from associated pools covered with free‐floating plants. 2. After the lake was refilled, the system was characterized by oxygen saturation or over‐saturation, neutral to basic pH, and high phosphorus, nitrogen and silicate concentrations. Ratios of total nitrogen (TN):total phosphorus (TP) and chlorophyll a (Chl a):TP indicated that phosphorus was the primary limiting nutrient during the period of groundwater supply. Once groundwater pumping had ceased, there was a decrease in TN:TP and Chl a:TP ratios, suggesting N‐limiting conditions prevailed in some periods. 3. Before restoration, the phytoplankton community was dominated year‐round by Planktothrix agardhii; since restoration the community has been more diverse. This change has favoured grazing by mesozooplankton, and the onset of clear‐water phases in spring. 4. Abundant populations of small omnivorous fish maintained a high predation pressure on zooplankton, restricting the abundance of large‐bodied herbivores, which, in turn, allowed an increase in phytoplanton biomass and a decrease in water transparency. Based on this observation, together with the phosphorus concentration and the low abundance of filamentous cyanobacteria compared with previous studies, we suggest that top‐down control has played a key role in increasing transparency in Lake Rodó. 5. A nutrient reduction programme, by the mechanical harvest of floating plants, and a removal of small omnivorous fishes and stocking strictly with piscivores, could be key factors in the achievement of a stable clear‐water phase. However, if blooms of Microcystis or other similar genera occur in summer, additional measures (e.g. reduction of the hydraulic residence time) will be needed to improve water transparency. Copyright © 2001 John Wiley & Sons, Ltd.