Apparent digestibility of soybean coproducts in extruded diets for Nile Tilapia,Oreochromis niloticus

Soybean coproducts are important protein sources in aquaculture because of their amino acid profile. Tilapia can be reared on soybean coproducts as the only source of dietary protein without compromising growth. This study estimated apparent digestibility coefficients for five soybean coproducts for juvenile Nile tilapia, Oreochromis niloticus, fed with extruded diets. A reference diet and test diets consisting of 70% reference diet and 30% coproduct ingredient were formulated, along with 5.0 g kg^?1 chromic oxide (Cr₂O₃) as a marker. Apparent digestibility coefficients (ADC) for dry matter (ADCDM), gross energy (ADCGE) and crude protein (ADCCP) for soybean coproducts were estimated as 84.2–88.4%, 86.9–91.1% and 96.8–97.9%, respectively. ADCDM and ADCCP values did not vary among the ingredients, but low‐protein soybean meal exhibited lower ADCGE values than did soybean protein concentrate. ADCs of all amino acids were >95%, and mean ADCs for amino acids were similar to the values observed for ADCCP. Soybean coproducts had good nutritional value in extruded diets fed to tilapia. Methionine, histidine and valine were the limiting amino acids in all evaluated ingredients.     

Calyculin A,an enhancer of myosin,speeds up anaphase chromosome movement

Actin and myosin inhibitors often blocked anaphase movements in insect spermatocytes in previous experiments. Here we treat cells with an enhancer of myosin, Calyculin A, which inhibits myosin-light-chain phosphatase from dephosphorylating myosin; myosin thus is hyperactivated. Calyculin A causes anaphase crane-fly spermatocyte chromosomes to accelerate poleward; after they reach the poles they often move back toward the equator. When added during metaphase, chromosomes at anaphase move faster than normal. Calyculin A causes prometaphase chromosomes to move rapidly up and back along the spindle axis, and to rotate. Immunofluorescence staining with an antibody against phosphorylated myosin regulatory light chain (p-squash) indicated increased phosphorylation of cleavage furrow myosin compared to control cells, indicating that calyculin A indeed increased myosin phosphorylation. To test whether the Calyculin A effects are due to myosin phosphatase or to type 2 phosphatases, we treated cells with okadaic acid, which inhibits protein phosphatase 2A at concentrations similar to Calyculin A but requires much higher concentrations to inhibit myosin phosphatase. Okadaic acid had no effect on chromosome movement. Backward movements did not require myosin or actin since they were not affected by 2,3-butanedione monoxime or LatruculinB. Calyculin A affects the distribution and organization of spindle microtubules, spindle actin, cortical actin and putative spindle matrix proteins skeletor and titin, as visualized using immunofluorescence. We discuss how accelerated and backwards movements might arise.     

A comparison of catch rates of artificial lures from an automated handline fishery at Shetland,UK

Automated handlining (jig fishing) has recently been trialled in waters around Shetland, UK. Although different types and colours of artificial lures are commercially available there is a paucity of information available on the effects of either lure design or lure colour on resulting catches. We compared the catch rates of (1) five colours of rubber eel tube lures; and (2) five different designs of artificial lure commonly used in handline fisheries. Lure colour did not significantly affect catches of pollack (Pollachius pollachius), saithe (Pollachius virens), cod (Gadus morhua), ling (Molva molva) or tusk (Brosme brosme). Cod showed a preference for lower hooks on the six hooks per reel set-up when lures were black and pollack showed a preference for lower hooks when the lures were blue. There were no significant differences in catches of saithe, cod, ling or tusk between the five lure types. However, catches of pollack on a novel ‘sonar’ lure were lower than on other lures. No evidence of a preference for any hook position on the reels was found with any of the lure types.     

Influence of chilling on potato tuber respiration,sugar, O-dihydroxyphenolic content and membrane permeability

The response of four potato cultivars to various temperatures was evaluated in respect to respiration, sugar and phenolic content, and ion leakage from cut tissue sections. Respiration decreased with decreasing temperature from 20° to 0°C but after 24 hours at 0°C began to increase and reached a maximum after 10 days at 0°C, then drifted downward. No distinct break in an Arrhenius plot of the respiration data from 20° to 0°C was observed. Reducing and non-reducing sugars did not change initially between 20° and 0°C and did not increase until after 6 or 7 days at 0°C. The magnitude of the increase in sugars varied between cultivars. Only one cultivar significantly increased in phenolic content during chilling. Ion leakage remained constant from 20° to 0°C then showed a transient increase within 24 hours at 0°C. A sustained increase in leakage did not occur until after 10 days at 0°C. Cultivars varied in the rate and magnitude of the increase. The respiratory rise could not be attributed to an increase in sugar content or an increase in membrane permeability. Also, the initial increase in sugars preceded the sustained increase in ion leakage. Differences observed between cultivars in the parameters measured were not considered sufficient to explain differences in chilling sensitivity.     

地面平养蛋鸡就巢行为的遗传改善

在许多发达国家,存在着一种放弃利用传统鸡笼饲养蛋鸡的趋势,并且提供了替代型饲养系统及设施。如：散养系统（图1）、室内地面放养（图2）、大鸟笼式饲养系统（多层式地面平养禽舍）（图3）、改良式笼养系统（增设巢、沙浴和栖木等装置）（图4）。     

The effect of the interaction of tree slenderness and relative height with ring width on wood density in <Emphasis Type="Italic">Abies balsamea</Emphasis> and <Emphasis Type="Italic">Picea glauca</Emphasis>

Wood density affects the strength of lumber and paper products. Despite considerable research, however, the key factors influencing wood density are still not fully understood. The aim of this study was to analyze the effects of variables within and among trees on the density of current wood growth along the stem in order to further understanding and prediction of wood quality. Correlation analyses together with linear mixed effects and randomForest modelling were carried out using stem analysis and tree-level data from long-term balsam fir and white spruce stand density experiments in Eastern Canada. Wood density showed highly structured patterns of variation among trees. Mixed effects and randomForest models, which incorporated tree-level effects accounted for much of the wood density variation. The three most influential variables identified by randomForest analysis for both species were tree slenderness, relative height and ring width. Wood density increased with slenderness and relative height, and these variables affected relationships of wood density to ring width. Wood density is associated with interacting variables within and among trees including tree slenderness and relative height. Wood density is related to ring width, but this relationship is modulated by tree-level influences which likely reflect mechanical stability requirements.     

Evaluation of retinal images for identifying individual dogs

OBJECTIVE: To F whether vessels in the ocular fundus changed over the lifetime of Beagles and whether any changes were substantial enough to likely preclude positive identification of individual dogs by use of their retinal vascular patterns. ANIMALS: 18 Beagles. PROCEDURES: Fundic photographs of both eyes of 18 Beagles taken at 1 or 3, 5, and 7 or 9 years of age were digitalized. Photographs were analyzed by use of 2 software programs. One was used to determine vessel numbers and widths and the other to determine the locations of the 3 largest vessels. Measurements were compared over time periods in the life of each dog. Only observations made at baseline (1 or 3 years of age) and again at 5 and 9 years of age were included in the statistical analysis, as these points were common to all dogs. RESULTS: No significant changes in numbers or locations of the blood vessels were detected over time. Widths of the vessels decreased significantly as the dogs aged. CONCLUSIONS AND CLINICAL RELEVANCE: The ocular fundus of Beagles changed over each dog's lifetime in that the retinal blood vessels became smaller but did not change in number or location. Results suggest that digitalized retinal images can likely be used to identify dogs over their lifetimes.