bluuebunny/crossref_metadata_2025 huggingface dataset:
Allometric Model for Leaf Area Estimation in Black Pepper (Piper nigrum L.)
Authors: Kandiannan K. , Kailasam C. , Chandaragiri K. K. , Sankaran N.
Published: March 2003

Black pepper (Piper nigrum L.) is an important spice used in cooking and medicine. It is cultivated in more than 20 countries in Asia, Africa and Latin America. India is a major producer, consumer and exporter of black pepper. Leaf area (LA) is an indicator of crop growth and productivity. This study was undertaken to develop a method of estimating the individual LA of black pepper directly without the necessity for time‐consuming area measurements. Ten black pepper lines were used in the study. Ninety matured leaves were collected from each line and an allometric relationship was derived by logarithmic transformation between actual leaf area (ALA) measured using the electronic leaf area meter LI‐3000 A (LI‐COR, Inc., Lincoln, NB) and leaf length (LL). The correlation coefficient (r) between ALA and LL ranged between 0.8692 and 0.9644 and the standard error (S.E.) between 0.0822 and 0.1149. The allometric models for 10 lines were: Panniyur 1, LA=0.7114 (LL)1.8409; Panniyur 2, LA=0.3692 (LL)2.067; Panniyur 3, LA= 0.6148 (LL)1.8838; Panniyur 4, LA=0.8355 (LL)1.7694; Sreekara, LA=0.8984 (LL)1.6692; Subhakara, LA=0.8384 (LL)1.738; Panchami, LA=0.3691 (LL)2.0749; Pournami, LA=0.4487 (LL)1.9718; Kottanadan, LA=0.3474 (LL)2.0634; P‐24, LA=0.7579 (LL)1.654. These allometric models were used to calculate LA, which was then compared with the actual LA, and the correlation coefficient (r) between them was found to be > 0.99. These allometric models can be used to estimate the LA of individual leaves of black pepper. The approximate total LA of a vine can be obtained using following formula: total leaf area of black pepper vine (cm2) = number of laterals per vine × number of leaves per lateral × leaf area of individual leaf.
Stability and Adaptability of Cultivars in Non‐balanced Yield Trials. Comparison of Methods for Selecting ‘High Oleic’ Sunflower hybrids for Grain Yield and Quality
Authors: Lu´quez J. E. , Aguirrezábal L. A. N. , Agüero M. E. , Pereyra V. R.
Published: March 2003

The best‐yielding and most stable cultivars are identified by growing cultivars in different environments. The stability of grain‐quality traits has been less thoroughly investigated than the stability of grain yield. High‐oleic hybrids of sunflower have been available on the Argentinian seed market for several years. Research on the stability of these genotypes is scarce. The objectives of this work were (i) to compare, using three different methods, the stability and adaptability of high‐oleic hybrids for grain yield and oil and oleic acid contents, and (ii) to explore the advantages and disadvantages of each method in selecting stable or adapted genotypes with high grain yield and high quality. Stability and adaptability analyses were performed on results for grain yields and oil and oleic acid contents of 35 high‐oleic sunflower hybrids from 17 comparative yield trials conducted over 2 years in Argentina. Stability was estimated using two methods: Fisher's protected least significant difference (LSD) test, which compared hybrids with the best‐yielding hybrid in each environment, and the test of relative yield (RY), which uses standard deviation as the measure of stability. Adaptability was estimated using Piepho's method of ‘multiple comparisons with the best’. These three methods can be applied to unbalanced data. Piepho's method made little discrimination amongst the hybrids. The LSD and RY tests coincided in classifying the hybrids as stable and unstable in 85 % of cases for grain yield and 76 % for oil content. It is concluded that the most convenient method depends on characteristics of the experimental design and of variability of the evaluated trait. Results from the LSD test depend on the number of environments in which the cultivar is tested. The RY method is valuable for classifying some cultivars as high‐yielding and stable, avoiding the problem of high‐yielding environments biasing the general average. Use of both methods together could be effective for classifying hybrids when the number of environments is adequate.
Photobiologische Unkrautregulierung annueller Ackerunkräuter
Authors: Juroszek P. , Gerhards R. , Kühbauch W.
Published: March 2003

Photocontrol of weed germination of arable annual weeds

Field studies were conducted to test the effect of light during soil tillage on the emergence of common weed species. Soil tillage was conducted at night or during daylight. In 20 out of a total of 23 field experiments, weed density after nighttime tillage was reduced compared to conventional daytime tillage. The average reduction of weed density attributable to photocontrol was 28.4 %. Results of field trials in the literature suggest that the emergence of Chenopodium album, Matricaria species and Stellaria media is especially reduced by nighttime tillage practices, but photocontrol had almost no effect on the emergence of Galium aparine and Polygonum convolvulus. The level of reduction of weed emergence after nighttime tillage was very variable. Important factors affecting this variation were: (1) the different light sensitivities of weed species, (2) the different light sensitivities of populations within one species, (3) the dormancy status of the seeds in a natural seed bank, and (4) the variation of light sensitivity of seeds.
Annual Medicago as a Smother Crop in Soybean
Authors: Sheaffer C. C. , Gunsolus J. L. , Grimsbo Jewett J. , Lee S. H.
Published: March 2003

Use of conservation tillage and narrow row spacing in soybean [Glycine max (L.) Merr.] production has led to increased use of herbicides for weed control. Some producers are seeking alternative weed control methods, such as smother crops, that would reduce dependence on chemical weed control. A successful smother crop must compete strongly with weeds but minimally with the crop. In four environments, we intercropped three annual Medicago spp. (medics) with soybean to test their utility as a smother crop for weed control. Annual medics were intercropped with soybean at rates of 0, 85, 258, or 775 seeds m−2, and the intercrops were grown with and without weed control. Increasing medic seeding rate decreased weed yields but also reduced soybean herbage and grain yields. For the weed‐controlled treatment, average soybean grain yields declined 7 kg ha−1 for every 10 seeds m−2 increase in medic seeding rate. Soybean grain yield was lower when grown with Medicago scutellata L. cv. Sava than when grown with Medicago polymorpha L. cv. Santiago or Medicago lupilina L. cv. George. Soybean grain yield was negatively related (r=−81) to medic herbage production. In the autumn following soybean harvest, medic residue ranged from 200 to 3700 kg ha−1 depending on the location and seeding rate. Medics provided residue for soil protection, suppressed weeds, but also reduced soybean yields.
Influence of Rhizosphere Ionic Strength on Mineral Composition, Dry Matter Yield and Nutritive Value of Forage Chicory
Authors: Neel J. P. S. , Alloush G. A. , Belesky D. P. , Clapham W. M.
Published: March 2003

Animal manure and urine deposition can cause localized patches of high ionic strength (IS) soil in pastures, influencing plant production, nutritive value and sward composition. Chicory (Cichorium intybus L.) appears to thrive in high‐nutrient input situations, but no information is available on chicory response to increasing IS. In a greenhouse experiment, we evaluated the effect of rhizosphere ionic strength (0.9, 4.0, 8.0 and 12.0 dS m−1) on productivity and nutritive value of chicory. Dry matter production decreased linearly as IS increased. Shoot concentrations for Ca, Na and Cl increased as IS increased. All mineral concentrations, except Cu, were substantially higher than or equal to the highest concentrations reported for forages. At all IS, nitrate‐N and K exceeded maximum recommendation for ruminant diets. The sodium level could be high enough to reduce dry matter intake at the highest IS level. Crude protein and energy estimates indicate chicory would support production levels equivalent to those of other high‐quality forages. In vitro organic matter disappearance increased as IS increased. Chicory as a component of a forage mixture could help stabilize forage yield in pastures and also shows promise for use as a nutrient mop in feedlot areas, where excess soil nutrients are a problem.
Assignment of six genes to bovine chromosome 13
Authors: Schläpfer J. , Stahlberger‐Saitbekova N. , Womack J. E. , Gaillard C. , Dolf G.
Published: March 2003

Six previously unassigned genes have been assigned to the BTA13 by means of somatic cell hybrid analysis. Polymerase chain reaction primer design for the amplification of AHCY, PLTP, PPGB and PCK1 was based on nucleic acids sequence information of homologous genes on HSA20. Primers for PDYN and ASIP were designed from porcine and bovine sequence information, respectively. Homology was established by sequence analysis. These assignments support the previous finding of a conserved syntenic relationship between HSA20 and BTA13 and contribute to the understanding of the chromosomal evolution of BTA13. This is significant since the prion protein gene, thought to play a key rule in the development and course of bovine spongiforme encephalopathy is also located on BTA13.
Components of heterosis for growth traits and litter size in line crosses of mice after long‐term selection
Authors: Mohamed  , Rottmann  , Pirchner
Published: March 2003

Strains selected for 54 generations for large 8‐week weight (N8, S8), for small weight (N6, S6), for high 3–5‐week gain and low 8‐week weight (N1) as well as unselected randomly mated control strains (N9, S9) were crossed, and F1, F2 and both back crosses created. N strains are derived from a NMRI base, S strains from a synthetic four‐way cross among inbred lines. Heterosis for 8‐week weight (8‐ww) was some 6%, but 30% for 3–5‐week gain and it was on average negative (22%) for 5–8‐week gain. When epistatic effects were taken into account, it appeared that heterosis for 8‐ww was largely due to beneficial effects of non‐parental gene combinations, i.e. additive × additive epistatic effects were negative. These non‐parental combinations neutralized the mostly negative dominance effects. The latter were mostly positive for early gain but in all 9 line crosses negative for late gain. The digenic effects of the non‐parental origin were not large enough to balance the negative dominance effects for late gain, so that heterosis was negative. It appears therefore that early and late gain are affected by different sets of genes. Maternal additive effects on 8‐ww and early gain are smaller than direct additive effects but mostly of similar sign. For late gain there appears to be no connection with direct additive effects. Direct litter heterosis was almost 50% but much of this was due to positively acting recombinational gene combinations, while direct litter dominance was mostly negative. Maternal additive effects on litter size differed depending on whether they were estimated from dams with crossbred or with purebred litter. Heterosis was small in crosses between control strains. Heterosis caused by recombinant gene pairs should be amenable to improvement by selection.
Identification of monozygous twins and microsatellite mutation rate in pigs from QTL linkage analysis data
Authors: Grapes L. , Malek M. , Rothschild M. F.
Published: March 2003

In previous work, microsatellite markers have primarily been tools for genome studies. However, the use of marker data can be extended beyond its original intent to maximize the amount of information obtained. There have been few studies to determine the occurrence of monozygous (MZ) twins in pigs. The advent of DNA marker technology, and microsatellites in particular, allows MZ twins to be identified based on their genotype data. To determine if MZ twin births occur in pigs, genotypes for F2 individuals, n=525, from 65 Berkshire × Yorkshire families were examined. One pair of female twins was found to have matching genotype data (95% CI: 0–2.94 twins). This is a unique result since there have been no published reports to date of twin pigs that survived until birth. Additionally, three dinucleotide microsatellite mutations were found after screening 134 565 meioses of 125 loci spanning the entire genome and the X chromosome. The average mutation rate for the population, n=570, was 2.23 × 10–5 (95% CI: 6.17 × 10–6–6.51 × 10–5). A mutation rate similar to this was published earlier for dinucleotide repeat microsatellite mutations in swine.
Genetic variances due to imprinted genes in cattle
Authors: ENGELLANDT TH. , TIER B.
Published: March 2003

The effect of paternally expressed, i.e. maternally imprinted, genes on slaughter records from 2744 German Gelbvieh finishing bulls were estimated. Significant effects of paternal gametes were found for two fatness traits and an estimate of meat content. Paternally expressed genes explained 14 and 16% of the phenotypic variances for pelvic fat and kidney fat, respectively. Ignoring paternal gametic effects resulted in inflated estimates of the additive genetic variances. The heritabilities of pelvic and kidney fat dropped from 0.31 to 0.16 and from 0.59 to 0.28, respectively, when paternal gametes were fitted. A 15% influence of paternally expressed genes and a reduction in heritability of 20% were also found for estimated meat content. Simulation studies demonstrated that the uncorrelated random effect of the sire is a useful indicator for the presence of paternal gametic effects in variance component estimations. The presented results correspond well with findings in swine, where a paternally expressed QTL at the Igf2 gene influences similar trait complexes. A viable speculation could therefore be that an imprinted bovine Igf2 gene caused the effects described here.
Free amino acids in plasma of neonatal calves are influenced by feeding colostrum for different durations or by feeding only milk replacer1
Authors: Hammon H. M. , Blum J. W.
Published: March 2003

Introduction  Newborn development is characterized by high protein synthesis and nitrogen (N) turnover rates in many tissues, especially in the gastrointestinal (GI) tract (G
oldspink and K
elly 1984; Y
oung et al. 1988; S
immen et al. 1990; X
u 1996). Colostrum provides particularly large amounts of nutrients (especially proteins) and immunoglobulins as well as non‐nutrient growth‐promoting factors; it therefore plays a major role in the development of the neonatal gut, especially protein synthesis, and other organs, as shown in several species including cattle (B
erseth et al. 1983; P
atureau M
irand et al. 1990; C
ampana and B
aumrucker 1995; O
dle et al. 1996; X
u 1996; B
urrin et al. 1997). Rates of body protein synthesis and N turnover were greater during enteral than during parenteral feeding, indicating considerable involvement of the GI tract in protein metabolism (D
uffy and P
encharz 1986).

Protein components in colostrum provided about 35% of amino acids (AA) in newborn lambs, suggesting that amounts of ingested protein with colostrum greatly influence the AA status of the neonate (Y von et al. 1993). Glutamine and glutamate are the most abundant AA in bovine milk protein (M
eijer et al. 1993) and glutamine is of special interest for postnatal gut development (S
ouba 1991; K
imura 1996; H
eird 1998). The glutamine:glutamate ratio was markedly changed in neonatal calves (D
emign&
eacute; and R&
eacute;
m&
eacute;
sy 1979) after colostrum intake.

Recently, we have demonstrated that gut growth and absorptive capacity of the intestine, as well as metabolic and endocrine changes in newborn calves, are greatly dependent on amounts of ingested colostrum (H ammon and B
lum 1997, 1998; B&
uuml;
hler et al. 1998). Based on that AA absorption, metabolism and status may be influenced by amounts of fed colostrum. Therefore in this study we have tested the hypothesis that feeding colostrum for different durations, or feeding only milk replacer, affects plasma protein and free AA concentrations during the first week of life in calves.
Homeostatic adjustments of iodine metabolism and tissue iodine to widely varying iodine supply in 125I labeled rats
Authors: Kirchgessner By M. , He J. , Windisch W.
Published: March 2003

Introduction  The homeostatic regulation of nutrient flow through the body is a fundamental ability of living organisms and has been shown to be active also in the case of several trace elements (K
irchgessner 1993; K
irchgessner et al. 1997). The basic function of homeostasis is to maintain the body’s internal status of the trace elements within physiologically tolerable margins by controlling at least one of the major trace element fluxes: the true absorption of the trace elements from the diet into the body, the reflux from the body into the faeces (endogenous faecal excretion), and the urinary excretion. Furthermore iodine may be a candidate to homeostatic regulation since dietary iodine contents may vary over a wide range and it may be important to the organism to maintain a constant internal status also of this essential trace element. However, quantitative iodine balance measurements are hardly available from the literature and thus knowledge about the existence of iodine homeostasis and its mode of action is still fragmentary. An additional problem also was the lack of appropriate methods to quantify true absorption and endogenous faecal excretion of iodine. However, a recent study has overcome this methodological barrier by adapting the isotope‐dilution technique to iodine (W
indisch et al. 1999). Therefore, the aim of the present experiment was to quantify possible homeostatic adaptations of iodine metabolism to dietary iodine ranging from deficient to excessive supplies and to measure the interactions to tissue iodine.
The leucine metabolite 3‐hydroxy‐3‐methylbutyrate (HMB) modifies protein turnover in muscles of laboratory rats and domestic chickensin vitro
Authors: Ostaszewski P. , Kostiuk S. , Balasińska B. , Jank M. , Papet I. , Glomot F.
Published: March 2003

This study was conducted to assess thein vitroeffects of leucine and 3‐hydroxy‐3‐methylbutyrate (HMB) on protein synthesis and degradation in isolated rat and chick muscles. Isolated muscles — extensor digitorum longus (EDL) and soleus (S) in rats and EDL and tibialis anterior (TA) in chicks — were taken out intact and incubated in Krebs—Henseleit buffer with [14C]phenylalanine. Protein synthesis was then determined by measuring [14C]phenylalanine incorporation into protein and protein breakdown was estimated by net release of tyrosine from muscle proteins. In all muscles investigated leucine stimulated protein synthesis (average 20%; p < 0.05 versus control) but only slightly reduced proteolysis (average 8%, NS). In contrast, HMB had no significant effect on protein synthesis but consistently decreased protein degradation in the range from −29% (p < 0.01 versus control) in rat extensor digitorus longus to −5% (NS) in rat soleus muscles. HMB appeared to suppress protein degradation more in white muscle fibres than in red muscle fibres (at least in the rat). These data support observations in humans indicating that HMB decreases muscle proteolysis. It is suggested that metabolism of leucine to HMB could be responsible for the reported suppressive effects of leucine on protein breakdown.
Factors affecting ascorbic acid biosynthesis in chickens. I. Adaptation of an assay and the effect of age, sex and food deprivation
Authors: Hooper C. L. , Maurice D. V. , Lightsey F. , Toler E.
Published: March 2003

The objective of this study was to adapt an assay to measure L‐gulonolactone oxidase (GLO) activity, the final step in ascorbate synthesis, in chickens and use the procedure to study the effect of gender, age, and food deprivation. To adapt a procedure used for mammalian tissues the kinetic constants were estimated using chicken kidney and assay conditions optimized in terms of storage of tissue and homogeneity of distribution. A series of experiments were conducted using the standardized assay with individual animals as the experimental unit. Gender differences were detected only in mature birds with male chickens having lower GLO activity than females. Time‐course changes in GLO activity in immature chicks were best characterized by a segmented response function consisting of a parabola joined to a straight line. The maximum value was estimated to occur at 13 days and from day 16 declined linearly. The functional relationship did not provide evidence of an early lag period or a peak at 4 weeks in immature chickens. Food deprivation in matched groups of birds demonstrated the effect of food on GLO activity in chickens. Food and water deprivation for 12 h and food deprivation for 24 h had no significant effect on GLO activity. Food deprivation for 48 h caused a significant decrease in GLO activity and it was not further depressed by deprivation for 72 h. Initial GLO activity was restored within 24 h of repletion. The results clearly demonstrated that gender, age, and starvation are determinants of ascorbate synthesis in chickens.
The effect of oligofructose and inulin on faecal characteristics and nutrient digestibility in healthy cats
Authors: Hesta M. , Janssens G. P. J. , Debraekeleer J. , De Wilde R.
Published: March 2003

The effects on faecal characteristics of different concentrations of oligofructose (0, 3, 6 and 9%) were investigated. The 6 and 9% supplemented groups differed significantly compared with the control group in almost all faecal characteristics. There were no significant differences regarding the macroscopical and chemical aspects of the faeces between the control and the 3% supplemented group. There was a trend for a lower pH of the faeces in the 3% supplemented group, suggesting a substantial effect on the faecal composition. In a second experiment, the effects of oligofructose (3%) and inulin (3 and 6%) on digestibility parameters were tested. In the supplemented groups the apparent protein digestibility was lower but this was due to a higher bacterial nitrogen content of the faeces. There were no significant differences between 3% inulin and oligofructose, although oligofructose seemed to be more easily fermentable, because of a trend to a higher concentration of short chain fatty acids (SCFA) in the faeces of the oligofructose group.
Determining metabolizable energy content in commercial pet foods
Authors: Laflamme D. P.
Published: March 2003

This study was conducted to assess the suitability of several equations for the estimation of metabolizable energy (ME) of pet foods. Sixteen canned and 31 dry cat foods and 24 dry dog foods representing the range of energy densities found in commercial adult, growth or all life stage products were evaluated in four separate experiments. In vivo ME was compared with estimates of ME generated by several previously published equations. The results indicated that the equation recommended by Association of American Feed Control Officials provided reasonable estimates of in vivo ME for both canned cat foods and dry dog foods, but proved unsuitable for dry cat foods. Better estimates were generated in each case using other published equations. Of the equations tested, the most accurate equations for estimating ME (kJ/g) without feeding trials were:

for canned cat foods: [(16.32 × protein) + (32.22 × fat) + (12.55 × NFE)];

for dry cat foods: [((GE × 1.209) – 1.911) × 4.184] or [((0.075 × g fat) + 2.766) × 4.184]

for dry dog foods: [GE=(24 × g protein) + (38 × g fat) + (17 × g NFE), then percentage energy digestibility=91.2 – (1.43 × percentage crude fibre in dry matter), then ME=(GE × percentage energy digestibility) – (4.34 × g protein)].

With the exception of high‐fibre weight‐management diets, the simple equation [((GE × 1.209)–1.911) × 4.184] also reliably predicted ME in dry dog foods.
Cats discriminate between cholecalciferol and ergocalciferol*
Authors: Morris J. G.
Published: March 2003

A comparison was made of the ability of ergocalciferol and cholecalciferol to elevate plasma concentrations of vitamin D and 25‐hydroxyvitamin D in cats. Cholecalciferol, given as an oral bolus in oil, resulted in a rapid elevation of plasma concentration of cholecalciferol followed by a rapid decline. In contrast, 25‐hydroxyvitamin D concentration in plasma increased until day 3 after administration and remained elevated for a further 5 days. When 337 μg of both cholecalciferol and ergocalciferol in oil were given as an oral bolus to 10 cats, the peak plasma concentrations of cholecalciferol and ergocalciferol occurred at 8 or 12 h after administration. Peak concentrations of cholecalciferol were over twice those of ergocalciferol (570 ± 80 vs. 264 ± 42 nmol/l). The area under the curve 0–169 h for cholecalciferol was also more than twice that for ergocalciferol. When ergocalciferol and cholecalciferol were administered in a parenteral oil‐based emulsion, higher concentrations of 25‐hydroxyvitamin D3 than 25‐hydroxyvitamin D2 were maintained in plasma. When both vitamins were included in the diet in the nutritional range, plasma concentrations of 25‐hydroxyvitamin D2 were 0.68 of those of 25‐hydroxyvitamin D3. Discrimination against ergocalciferol by cats appears to result from differences in affinity of the binding protein for the metabolites of the two forms of vitamin D. These results indicate that cats discriminate against ergocalciferol, and use it with an efficiency of 0.7 of that of cholecalciferol to maintain plasma 25‐hydroxyvitamin D concentration.
Performance and ileal histomorphology of rats treated with humic acid preparations*
Authors: Yasar S. , Gokcimen A. , Altuntas I. , Yonden Z. , Petekkaya E.
Published: March 2003

Summary As humic acid (HA) substances have antiphlogistic, adsorptive, antitoxic and antimicrobial properties, we studied the possible effects of Farmagülatör®, an organic HA preparation, on the rat performance, nutrient retention, ileal histomorphology and hydroxyproline (HP) content of the ileum in two experiments. In experiment 1, 48 male Wistar albino rats were allotted to three dietary treatments. Each was randomly assigned to four cages, each with four rats. The treatments consisted of a control diet (C) with no addition of Farmagülator® Dry or Liquid, a treatment with addition of 2.5 g/kg Farmagülator® Dry (FDry) and a control diet containing no FDry, but the rats had 3.5 ml/l Farmagülator® Liquid in drinking water (FLiquid). The experiment lasted for 20 days. Changes in live weight were recorded at days 10 and 20 of the experiment. At the end of 20 days, all rats were killed to collect samples of intestinal tissues for the measurements of histological parameters. In experiment 2, 30 rats weaned at 21 days of age were divided into three groups, each with 10 rats, and individually caged in metabolism cages for 10 days. The above three treatments were randomly assigned to rats for 10 days to record body weight and feed intake. During the last 5 days, faecal outputs were collected to determine the dry matter and nitrogen retention. In experiment 1, FDry and FLiquid rats significantly (p<0.05) gained more live weight than the control rats. Improved weight gain with HA preparations was found to be highly associated with a high epithelial surface area as there were significantly (p<0.05) longer villi heights and crypt depths and increased HP contents of ileum in the HA treated rats compared with the control rats. Although the increased weight gain in FLiquid rats did not significantly (p>0.05) differ from the control rats in experiment 2 in contrast to the result in experiment 1, the FDry rats significantly (p < 0.05) gained more weight than the control rats. This was primarily found to be associated with significantly (p<0.05) increased feed intake and nitrogen retention in FDry rats compared with the control rats. It can be concluded that HA preparations, especially FDry, caused increased weight gain in rats as overall of two experiments. The improved weight gain only by FDry preparation was associated with increased ileal epithelial mass, increased feed intake, improved feed : gain ratio and increased nitrogen retention in rats.
Influence of age and body size on the digestibility of a dry expanded diet in dogs
Authors: Weber M. , Martin L. , Biourge V. , Nguyen P. , Dumon H.
Published: March 2003

The objectives of the study were (i) to evaluate the effects of age and body size on the apparent digestibility of a dry expanded diet and (ii) to determine whether poor faecal quality could be related to lower nutrient utilization. Four breeds of dogs were used: six Miniature Poodles (MP), six Medium Schnauzers (MS), six Giant Schnauzers (GS) and six Great Danes (GD). Digestive trials were performed at 11, 21, 35 and 60 weeks of age. Faecal moisture and scoring were recorded at the same periods. Digestibility coefficients of all macronutrients increased significantly (p < 0.05) with age in all four breeds. Organic matter digestibility increased from 80.2 ± 1.5 to 85.5 ± 1.5% in MP; from 80.2 ± 0.9 to 86.3 ± 0.5% in MS; from 79.6 ± 4.2 to 88.9 ± 0.5% in GS and from 85.7 ± 1.5 to 88.4 ± 0.8% in GD. Crude protein digestibility increased from 74.5 ± 4.0 to 81.5 ± 1.9% in MP; from 74.3 ± 3.9 to 82.6 ± 0.9% in MS; from 71.8 ± 6.0 to 85.9 ± 0.9% in GS and from 80.8 ± 4.6 to 84.8 ± 1.3% in GD between 11 and 60 weeks of age, respectively. Mean faecal moisture also increased over the growth, except in GS. Nutrient digestibility was significantly higher in large dogs at all age periods. However, larger dogs showed lower faecal scores and increased faecal moisture.

In conclusion, these results show (i) an effect of age and body size on nutrients digestibility and (ii) that the lower faecal quality observed in healthy large breed dogs does not appear related to lower nutrient utilization.
Effects of Bacillus thuringiensisδδ‐endotoxins on food utilization, growth, and survival of selected phytophagous insects
Authors: Deml R. , Meise T. , Dettner K.
Published: March 2003

Feeding experiments using the Bacillus thuringiensisδ‐endotoxins, CryIA(c) and CryIIIA, were conducted with herbivorous insects from various orders (Lepidoptera, Coleoptera, Homoptera) in the laboratory. The mortality data obtained indicate a species‐specific susceptibility of the insects to the toxins whereby the feeding habits of the given animal seem to play a negligible part. An unexpected, severely damaging effect of CryIIIA on caterpillars was established, for the first time. By computing various development and nutritional indices it could be shown that retarded growth of the insects tested may not only be traced back to reduced feeding but also to a decreased utilization of food containing an endotoxin. The insect gut seems to be the site of operation and of storage or complete degradation of the endotoxins because neither in the faeces nor in the haemolymph and fat body, could the toxins and their degradation products, respectively, be detected hitherto by means of gel electrophoreses. An altering effect of the toxins on the gut‐microflora pattern is indicated from the first examinations but has to be further confirmed. Finally the applicability of these trials in corresponding examinations of transgenic plants producing B. thuringiensis toxin is dicussed.
Effects of essential oil formulations on Ceratitis capitata Wied. (Dipt., Tephritidae) adult flies
Authors: Passino G. Sanna , Bazzoni E. , Moretti L. , Prota R.
Published: March 2003

The effects on adult Ceratitis capitata of the ingestion of formulations containing different concentrations of some essential oils were examined. The bioassays were carried out using groups of C. capitata adults fed for 3 days with formulations containing a known concentration (0.25%, 0.5%, 1.0%) of essential oils. The oils, of different chemical composition, were obtained by steam distillation from aromatic plants collected during the balmy period. The essential oils of Rosmarinus officinalis and Salvia officinalis, which are rich in monoterpenic hydrocarbons and monoterpenic ketones, respectively, showed poor activity, whereas the oils of Cinnamomum zeylanicum and Thymus sp. showed a marked toxic effects (over 90% mortality after 72 h). This could be explained by the activity of cinnamic aldehyde (about 80% of the Cinnamomum oil) and carvacrol (68% of Th. capitatus oil and about 45% of Th. herba barona oil). The first consequence of ingesting even small quantities of essential oils was a depressive effect on the nervous system. Dissection of dead flies showed marked differences compared with the controls and microscopic examination revealed anomalies in the gut region.
Mating disruption for the control of the olive moth, Prays oleae (Bern) (Lep., Yponomeutidae) with the ajor sex pheromone component
Authors: Mazomenos B. E. , Ortiz A. , Mazomenos‐Pantazi A. , Stefanou D. , Stavrakis N. , Karapati C. , Fountoulakis M.
Published: March 2003

Abstract: Mating disruption to control the olive moth Prays oleae (Bern) was tested from 1992 to 1996 in olive groves in Greece. The major sex pheromone component (Z)‐7‐tetradecenal was formulated in β‐cyclodextrin (β‐CD) and polyvinyl chloride (PVC) polymers. Pheromone trap catches were reduced by up to 96–100% in the mating‐disruption plots. During the first year of mating disruption a treatment with Bacillus thuringiensis (var. kurstaki) (Bt) was applied to reduce the first generation or larvae. Fruit damage in the mating disruption plots was lower compared with the fruit damage in Bt, insecticide and untreated plots. In high fruiting years, the proportion of fruit damage was lower than in low fruiting years. Mating disruption applied in the same olive grove over several years progressively reduced the olive moth population from year to year.
Calling behaviour of adult female Helicoverpa armigera (Hübner) (Lep., Noctuidae) of overwintering generation and effects of mating
Authors: Hou M. L. , Sheng C. F.
Published: March 2003

The calling behaviour of overwintering generation females of Helicoverpa armigera and the effects of mating were studied in the laboratory at 24 ± 1°C and under reversed light‐dark cycle (16 h light : 8 h dark). Age had a significant influence on calling patterns. Based on calling age, mean number of calling bouts and total calling length of virgin females increased significantly, and mean onset time of calling advanced significantly from calling day 1 to subsequent calling days. Females of the overwintering generation exhibited more short bouts in calling, and some females that initiated calling on a previous day did not call on subsequent days. Mating had no effect on the overall patterns, but did affect calling behaviour. Mated females did not resume calling after mating during the same scotophase and, on the day following mating, mated females called less frequently and for a shorter duration, but thereafter increased to the same level of virgin females of the same calling age. Furthermore, as the moth aged, the percentage of mated females calling was lower than that of virgin females.
Effects of resin flow and monoterpene composition on susceptibility of lodgepole pine to attack by the Douglas‐fir pitch moth, Synanthedon novaroensis (Lep., Sesiidae)
Authors: Rocchini L. A. , Lindgren B. S. , Bennett R. G.
Published: March 2003

Resin flow differed significantly among three of six clones of lodgepole pine seed orchard trees, but did not differ among the clones categorized as susceptible or resistant to attack by the Douglas‐fir pitch moth. A stepwise regression analysis identified δ‐3‐carene, cyclohexene, and α‐terpinolene as significant compounds, explaining 49.9% of the variation in the number of attacks per tree. δ‐3‐Carene alone explained 41.8% of the variation in the regression, and analysis of variance showed that resistant clones consistently had high relative amounts (>17.9%) of this compound, whereas susceptible clones had low amounts (<10%). The significant effect by cyclohexene and α‐terpinolene in the stepwise regression appeared to be due to a correlation between α‐terpinolene and δ‐3‐carene in several clones, and that cyclohexene was only present in one clone, rather than any discernable biological relationship. Limonene co‐eluted with β‐phellandrene, so its role must be determined by additional study.
Studies on the significance of pathogenic fungi in the population dynamics of the Lesser Spruce Sawfly, Pristiphora abietina Christ. (Hym., Tenthredinidae)
Authors: Führer  , Rosner  , Schmied  , Wegensteiner
Published: March 2003

The population dynamics of Pristiphora abietina, an important pest in Norway spruce in central Europe, is significantly influenced by factors causing nymph mortality during the cocoon stage. In contrast to other findings reported in the literature, pathogenic fungi of the genera Beauveria, Paecilomyces and Metarhizium were found to be important natural enemies. Their epizootics occur soon after cocoon formation by the larvae in the ground litter, i.e. in June/July, and progress only slightly in autumn and winter. ‘Obscure’ mortality, which is ascribed mainly to abiotic factors, is observed more in winter. Field and laboratory experiments as well as histological analyses suggest that the fungal disease in nymphs is due to spore contamination occurring before cocoon formation, and that penetration of fungi from outside through the intact cocoon wall appears very unlikely. Thus, the infection rate of cocoons depends on the spore density in the ground litter of spruce stands during the cocoon spinning period of May/June. Perspectives for biocontrol arising from these findings are discussed.
The natural enemy complex of the gypsy moth, Lymantria dispar (Lep., Lymantriidae) in different phases of its population dynamics in eastern Austria and Slovakia – a comparative study
Authors: Hoch  , Zubrik  , Novotny  , Schopf
Published: March 2003

Parasitism and pathogen mortality of Lymantria dispar were compared between host populations of different densities in Slovakia and Austria. Over a period of 4 years, L. dispar eggs, larvae, and pupae were collected in a stage‐specific manner at three mixed oak stands in each country and reared in the laboratory to assess parasitoid and pathogen mortality. At sites with low host densities, L. dispar abundance was artificially augmented by exposing egg masses and young larvae. We ascertained marked differences between the natural enemy complexes of L. dispar populations in Slovakia and Austria. Overall, pathogens caused highest mortality in the former and parasitoids in the latter. Moreover, the species composition differed significantly between both countries. High variation was also observed between years and host populations at different densities. The investigations revealed that egg parasitization was low in Slovak L. dispar populations, and no egg parasitoids were found in Austria. Larval and pupal parasitism was low at sites with outbreak populations, but higher at the Austrian than at the Slovak site. The tachinid Parasetigena silvestris was the dominant species at elevated host densities. Nuclear polyhedrosis virus also caused significant mortality in these cases. An increase in parasitism by several species was noticed after the breakdown of L. dispar populations. The ichneumonid Phobocampe spp. caused high levels of parasitism during the post‐culmination years. At sites where host abundance increased in the first year of the study, significant differences between the Austrian and the Slovak locality could be ascertained. Mortality was low in the population at the latter site, and host abundance increased to outbreak levels the year after. The population at the Austrian site suffered high parasitism by the tachinids P. silvestris and Blepharipa pratensis and this might have contributed to the prevention of a further increase in L. dispar abundance in this locality. Braconids showed a strong reaction to the local, artificial increase in host density at study plots with innocuous L. dispar populations. Particularly high parasitism by Glyptapanteles liparidis was observed at the Austrian site, but G. porthetriae and Cotesia melanoscela also accounted for significant mortality in both low‐density populations. The artificial L. dispar populations were usually eradicated by natural enemies before pupation of the hosts.
DNA gyrase inhibitors: Novobiocin enhances the survival of Pimpla turionellae (Hym., Ichneumonidae) larvae reared on an artificial diet but other antibiotics do not
Authors: Büyükgüzel K.
Published: March 2003

Effects of novobiocin, nalidixic and oxolinic acids, which are potent antibacterial agents, on the survival and development of the hymenopterous endoparasitoid, Pimpla turionellae L. (Ichneumonidae) were investigated alone by rearing the larvae aseptically on chemically defined synthetic diets. Survival of the fifth instar larvae was not significantly affected by diets with different levels of antibiotics tested. A diet containing the lowest level of novobiocin significantly increased yields of pupae and adults. This level also significantly shortened the developmental time for fifth instar but had no significant effect on complete development of the larvae up to adult emergence. Oxolinic acid at the lowest level did not affect the survival but prolonged development of the insect. In general, the rate of development was significantly increased and the survival was decreased with high levels of the antibiotics. However, nalidixic acid caused a striking decrease in the survival at all tested levels. These results suggest that novobiocin and to a lesser extent oxolinic acid are compatible for addition to artificial diet for rearing P. turionellae, which is an important parasitoid used in biological control.
Kairomonal effect of some saturated hydrocarbons on the egg parasitoids, Trichogramma brasiliensis (Ashmead) and Trichogramma exiguum, Pinto, Platner and Oatman (Hym., Trichogrammatidae)
Authors: Paul A. V. N. , Singh S. , Singh A. K.
Published: March 2003

Abstract: Bioassay studies carried out on the egg parasitoids Trichogramma brasiliensis and T. exiguum with 11 straight chain‐saturated hydrocarbons, revealed that pentacosane and hexacosane recorded very high parasitoid activity index (PAI) and parasitism for both the parasitoids indicating high kairomonal activity. These were followed by docosane, tricosane, heneicosane, hexatriacontane and tetracosane, which may be grouped as favourable hydrocarbons showing varying levels of kairomonal activity for T. brasiliensis, as compared to eicosane, pentadecane, octacosane and heptadecane, which can be grouped as non‐favourable hydrocarbons. In the case of T. exiguum, pentacosane‐treated egg cards showed maximum parasitism followed by hexacosane, pentadecane, hexatriacontane, tricosane and docosane thereby indicating their kairomonal activity in comparison with heptadecane, tetracosane, eicosane, heneiocosane and octacosane which recorded low levels of parasitism. In the case of T. brasiliesnsis, tetracosane recorded the highest response at the lowest concentration, C1 (62.5 ng/cm2), which decreased as the concentration increased. Eicosane, heneicosane and docosane recorded the highest parasitism at C2 (125 ng/cm2). In heptadecane, tricosane, pentacosane and hexatriacontane the highest parasitism was recorded at the medium concentration, C3 (250 ng/cm2). Octacosane recorded the highest response at C4 (375 ng/cm2). Pentadecane and hexacosane‐treated egg cards showed their highest response at C5 (500 ng/cm2). In the case of T. exiguum, the lowest concentration, C1 evoked the highest response in hexacosane, whereas heptacosane, heneiocosane, docosane and tetracosane recorded the highest parasitism at C2. Eicosane, pentacosane and octacosane recorded maximum parasitism, at C3, whereas tricosane and hexatriacontane showed maximum parasitism at C4 and pentadecane at C5. These concentrations can be taken as the optimum concentration to increase parasitization by these parasitoids. The favourable hydrocarbons at their optimum concentration can be used for efficient management of these parasitoids in field releases.
How to distinguish most similar insect species – improving the stereomicroscopic and mathematical evaluation of external characters by example of ants
Authors: Seifert B.
Published: March 2003

Abstract: The non‐destructive investigation of type specimens, the need to interpret available taxonomic descriptions, and the requirement to give statistical evidence for a presented hypothesis will guarantee that careful investigation and numeric recording of phenotypic characters will remain the basis of taxonomic work in insects, even if the progress of molecular genetics should continue to unexpected levels. A process of how to discriminate most similar insect species by means of external morphology is explained step by step. The process includes: (a) the reproducible and practicable definition of characters; (b) the reduction of errors during stereomicroscopic investigation and data recording; (c) the application of pair comparisons in discriminative calculations; (d) the description and removal of allometric variance; (e) the use of discriminant functions; and (f) the final removal of variance by consideration of nest means. The avoidance or reduction of 10 types of error occurring during stereomicroscopic investigation is explained. A linear regression of a weighted (indexed) character against a measure of body size is the recommended method to describe continuous allometries. In the case of discontinuous allometries and/or if discrete worker castes are present, different regression lines are calculated with this method for up to four separate size intervals and then connected in the form of a single‐valued polygon. Two types of discriminant function, a linear function without consideration of character correlations and a function using the function values of normal distributions and considering character correlations, both proved to be powerful in separating most similar species. The whole procedure from the beginning of data recording to the final calculation can increase, in the most successful case, the portion of individuals outside the interspecific overlap range from 25 to 100%. In the opposite extreme, the procedure can increase the overlap and thus reveal pseudo‐discriminative characters or pseudo‐species that are artefacts of allometric growth.
Leaf Water Potential and Peroxidase activity in Quercus cerris and Quercus pubescens after Inoculation with Diplodia mutila
Authors: Ragazzi A. , Moricca S. , Vagniluca S. , Comparini C. , Dellavalle I.
Published: March 2003

Ten‐year‐old field‐grown Quercus pubescens Willd. and Quercus cerris L. individuals were inoculated with Diplodia mutila (teleomorph Botryosphaeria stevensii Shoe‐maker) to observe symptom evolution over 2 years. The experiments were carried out for the 3 years: 1991, 1992 and 1993. At the same time, the effect of D. mutila on leaf water potential and peroxidase activity was assessed on the leaves of 2‐year‐old seedlings from the same two species growing under controlled conditions (18 h day, relative humidity 75%), temperature 24/15°C day/night). Quercus pubescens was more susceptible than Q. cerris, and frequently exhibited dieback of the branch above the inoculation site. On the seedlings, the visible symptoms of infection were much more severe than on the older trees. The infected seedlings showed a lower leaf water potential than healthy seedlings, particularly those of Q. pubescens after the third week. The peroxidase activity was increased in infected Q. pubescens seedlings compared with both groups of control seedlings (wounded but not inoculated, and neither wounded nor inoculated) 14 and 21 days after inoculation. Leaf water potential and peroxidase activity are known indicators of stress which appear even before any visible symptoms; they could therefore serve as early indicators of D. mutila infection.