Microbiological quality of macaroni and noodle products obtained at retail markets.

The microbiological quality of macaroni and noodle products was determined by a statistically based national survey at the retail level. Geometric means of aerobic plate counts for macaroni and noodle products were 520 and 1,400 per g, respectively. Means for yeast and mold counts were 72 per g for macaroni and 100 per g for noodles. Means for counts of coliforms and Staphylococcus aureus were less than 3 per g for both products. Escherichia coli was not found in macaroni but was present in 0.5% of the noodle samples and ranged from 3 to 93 per g.     

Isolation and characterization of macaroni penguin (Eudyptes chrysolophus) microsatellite loci and their utility in other penguin species (Spheniscidae, AVES)

We report the characterization of 25 microsatellite loci isolated from the macaroni penguin (Eudyptes chrysolophus). Thirteen loci were arranged into four multiplex sets for future genetic studies of macaroni penguin populations. All 25 loci were tested separately in each of four other penguin species [Adélie penguin (Pygoscelis adeliae), chinstrap penguin (Pygoscelis antarctica), gentoo penguin (Pygoscelis papua) and king penguin (Aptenodytes patagonicus)]. Between eight and 12 loci were polymorphic per species. These loci are expected to be useful for studies of population genetic structure in a range of penguin species.     

Blood values of the canvasback duck by age, sex and season

Blood samples were obtained from canvasback ducklings from Manitoba and Saskatchewan and from immature and adult canvasbacks on the Mississippi River near LaCrosse, Wisconsin and the Chesapeake Bay. These samples were used to determine baseline data on red cell counts, hematocrit, total protein, glucose, cholesterol, hemaglobin and distribution of plasma proteins. Calculations were also made to determine mean corpuscular volume, mean corpuscular hemoglobin and mean corpuscular hemoglobin concentration. The major differences noted were between ducklings and adults. The former having higher total protein and lower hematocrit, glucose and cholesterol values. These hematologic values were collected in order to provide baseline information on apparently healthy canvasbacks, thereby providing disease investigators with a standard of comparison.     

Distress call alternation in peking ducklings (Anas platyrhynchos)

Peking ducklings (Anas platyrhynchos) were found to alternate their distress calls with those of conspecifics. This alternation response consisted of two components: a strong tendency to suppress vocalizing during the conspecific's calls and a weaker tendency to increase vocalizing (above the level given by birds tested in auditory isolation) following those calls. Similar results were obtained whether pairs of ducklings were tested or whether individual ducklings were tested with tape-recorded calls. Further, visual contact with the conspecific, or a mirror image, although not necessary for eliciting an alternation response, did have a significant facilitative effect on this response. This latter effect may have been due to the general arousal-reducing properties of the visual stimulus. Finally, in contrast to the strong response of ducklings to conspecific distress calls, they displayed a much weaker tendency to alternate their calls with (a) clicking sounds and 7.0-kHz tones with the same temporal patterning and intensity as the taped distress calls, (b) 3.8-kHz tones that additionally matched the dominant frequency of the taped calls, and (c) synthetic distress calls that also approximated the frequency modulation of the taped calls. These results indicate that the distress call alternation response is not simply an artifact of a more general orienting response in which ducklings inhibit their own vocalizations whenever they hear any salient auditory stimulus. Rather, the response appears to be quite specifically triggered by the sound of the sibling calls. The present results stand in contrast to the common assertion that young birds largely ignore the distress calls of siblings. These results are, however, consistent with recent literature emphasizing the importance of sibling interactions in the analysis of mallard early social attachments.     

Effect of cold-acclimation on oxygen uptake and glucose production of perfused duckling liver

The control of hepatic metabolism by substrates and hormones was assessed in perfused liver from young Muscovy ducklings. Studies were performed in fed or 24-h fasted 5-week-old thermoneutral (25 degrees C; TN) or cold-acclimated ducklings (4 degrees C; CA) and results were compared with those obtained in rats. Basal oxygen uptake of perfused liver (LVO2) was higher after cold acclimation both in fed (+65%) and 24-h fasted (+29%) ducklings and in 24-h fasted rats (+34%). Lactate (2 mM), the main gluconeogenic substrate in birds, similarly increased LVO2 in both TN and CA ducklings and the effect was larger after fasting. Both glucagon and norepinephrine dose-dependently increased LVO2 in ducklings and rats, but cold acclimation did not improve liver response and liver sensitivity to norepinephrine in ducklings was even reduced in CA animals. Liver contribution to glucagon-induced thermogenesis in vivo was estimated to be 22% in TN and 12% in CA ducklings. Glucagon stimulated gluconeogenesis from lactate in duckling liver and the stimulation was 2.2-fold higher in CA than in TN fasted birds. These results indicate a stimulated hepatic oxidative metabolism in CA ducklings but hepatic glucagon-induced thermogenesis (as measured by LVO2) was not improved. A role of the liver is suggested in duckling metabolic acclimation to cold through an enhanced hepatic gluconeogenesis under glucagon control.     

Levamisole enhances immunity in ducklings vaccinated against Riemerella anatipestifer

Oil‐adjuvant‐inactivated vaccine is one of the most cost‐effective vaccines used to protect ducklings against RA infection; however, it does not provide complete protection in very young ducklings with immature immune systems. In the current study, LMS was used as an immunopotentiator to improve the immune system in ducklings. Serum immunoglobulin (Ig)G titers and the secretions of both Th1‐type (IFN‐γ and IL‐2) and Th2‐type (IL‐4 and IL‐10) cytokines were higher in ducklings that had been vaccinated with LMS. In addition, a significantly higher T‐lymphocyte proliferation rate was obtained with the addition of LMS. Furthermore, all of the ducklings vaccinated with LMS were protected against RA on the 9th day post‐vaccination, whereas only 69.2% of the ducklings were protected in the group that did not receive LMS. These results suggest that LMS might be a useful adjuvant to enhance the immune response of ducklings. The use of LMS may also alleviate local injection lesions, caused by the oil‐emulsion vaccine, by reducing the dose of the vaccine.     

Study on toxicological mechanism of moniliformin

A mycotoxin was extracted and purified from a strain of Fusarium moniliforme var. subglutinans isolated from mouldy corn seeds harvested in a serious Keshan disease region in Shaanxi Province. The purification procedure involves water extraction, ion exchange chromatography, desalination and crystallization. Its UV spectrum, IR spectrum and NMR are identical with that of the moniliformin. The toxin is highly toxic to young Beijing ducklings. The electrocardiogram (ECG) of the duckling was changed immediately after feeding with moniliformin. The cardiac muscle cells of Beijing ducklings were injured by the toxin. Toxicity may be alleviated to certain extent by applying adequate dosage of Selenium (3.18 X 10(-10) mol/L of H2SeO4) prior to moniliformin treatment. The permeability of the cardic muscle cells of the rats and young ducklings was damaged posterior to the injection of the toxin as tested by extracellular marcromolecular tracer (HRP) method. The relationship between moniliformin and Keshan disease was discussed. We consider that the moniliformin may be the causal agent of the disease.     

A case of infanticide in the Spot-billed Duck in circumstances of high breeding density

The first observations of infanticide by a precocial avian species, Spot-billed Duck (Anas poecilorhyncha), were recorded on a small pond at Yatsu tidal flat, central Japan, from May to June 2000, where six families of conspecific and one Gadwall A. strepera family, respectively, occupied territories. A female Spot-billed Duck with 11 ducklings attacked ducklings of all the other families killing eight conspecifics and three of the Gadwall. High breeding density (15.0 families/ha) may have increased the aggression of the female. Electronic Publication     

The diet of Grey Herons Ardea cinerea breeding at Loch Leven, Scotland, and the importance of their predation on ducklings

Regurgitations from nestling Grey Herons Ardea cinerea at Loch Leven, Scotland, April-July 1981–83, contained mainly three types of prey:perch, brown trout and ducklings. The diet varied markedly through the season but not between years. As the heron breeding season progressed, perch occurred in fewer regurgitations and ducklings in more. There was no seasonal variation in the occurrence of brown trout. Regular collections of duckling down from the heronry suggested that the consumption of ducklings peaked in early June. The ducklings taken by herons were less than 10 days old, Mallard ducklings predominating before mid June and Tufted ducklings later. Most ducklings were taken by only a few herons:those that bred earliest and which initially fed their young on perch. Ducklings became a major part of their diet in the late nestling period and broods fed on ducklings fledged no more or fewer young than others. Herons feeding their young on brown trout took ducklings rarely, if ever. It is argued that variation in the contents of regurgitations resulted from three interacting variables; the type of feeding habitat used by individual Grey Herons, the date at which they bred and the date that regurgitations were produced by their nestlings. The numbers of ducklings taken by herons were calculated to be about 230 in 1981 and 291 in 1982, about 5% of Mallard and 3:b of Tufted ducklings estimated to have hatched annually. Assuming herons continued to consume ducklings at the same rate after their young had dispersed, the figures for Tufted ducklings would be higher but still only about 4% in 1981 and 6% in 1982. Compared with total duckling losses of over 75%, predation by Grey Herons was minor and did not affect duckling production in the years concerned.     

Activity budgets of captive Laysan ducklings (Anas laysanensis)

This study examined how diurnal activity budgets, visibility to observer, and distance to parents changed during the day and during three stages of development of captive Laysan ducklings. All behaviors except feeding, swimming, and terrestrial locomotion varied significantly across the stages of development. There was a significant time of day effect for 5 behaviors: stationary, flying, swimming, under female, and lying. A significant interaction between stage and time of day for 4 behaviors, viz., stationary, flying, under female, and out of sight, was also found. Young ducklings followed the female, were under the female, or were out of sight significantly more often than older ducklings. Older ducklings performed maintenance behaviors or boundary walking, or were stationary, flying, social, lying, or lying out of sight significantly more often than younger ducklings. Swimming and flying were most often performed late in the day, and the ducklings were stationary most often in early and late periods of the day. They were also most often under the female during early and late periods of the day. © 1992 Wiley-Liss, Inc.     

Comparing dietary preferences of Bufflehead ducklings in Western Canada through gut content and stable isotope analysis

Aquatic invertebrates are essential for duckling growth and development. We present results on the trophic status and dietary analysis of Bufflehead (Bucephala albeola) ducklings from the boreal breeding grounds of western Canada. We estimated dietary preference by comparing invertebrates found in Bufflehead diets to those identified in standardized dip net samples at their wetland feeding sites. Stable isotope ratios of Bufflehead and their prey were used as a second estimator of trophic position. Bufflehead ducklings preferentially foraged for larval Dytiscidae (predaceous diving beetles; 46% of total dietary biomass), Zygoptera larvae (damselflies; 14%) and non-Dytiscidae adult Coleoptera (5%; mainly Haliplidae). Results from stable isotope analyses supported these results; the separation between primary and secondary invertebrate consumers and ducklings was significant for all possible contrasts when considering nitrogen isotope ratios (Tukey HSD; P < 0.001). We iteratively explored all possible combinations of δ¹⁵N and δ¹³C data to generate a proportional range over which each food source may contribute to Bufflehead stable isotope signatures; these results suggested larval Zygoptera and larval Dytiscidae figure prominently in diets when accounting for isotope fractionation. The incorporation of prey availability into the metric of dietary preference, as opposed to the tabulation of ingested items alone, reduces the importance of invertebrate groups such as adult Dytiscidae as highlighted in previous studies.     

Energy requirements for growth and maintenance in macaroni and rockhopper Penguins

Summary Energy requirements for growth and maintenance of macaroni and rockhopper penguin chicks at Marion Island, southern Indian Ocean, were estimated from rates of oxygen consumption and body composition analysis. Mass-specific energy expenditures of both species increased to levels 1.5 times that of hatchlings within 14–21 days of hatching and subsequently decreased. Lipid was initially accumulated slowly but the rate of accumulation increased after 30 days of age when male parents joined the females in feeding the chicks. Lipid, however, decreased markedly after 45 days of age and was presumably metabolized. Protein was laid down throughout the growth period, but doubled its initial rate of accumulation between 22 and 35 days of age. Thereafter the rate decreased until independence. Daily energy requirements of macaroni and rockhopper penguins increased from 417 and 211 kJ d^-1, respectively, in the first week after hatching to peaks of 1540 and 1170 kJ d^-1 about halfway through the growth period before decreasing until independence. Total energy requirement for growth and maintenance was estimated to be 76200 kJ for macaroni penguins and 59400 kJ for rockhopper penguins, of which growth energy comprised 38% and 28%, respectively. Based on the energy requirements and population data, macaroni and rockhopper penguin chicks at Marion Island consume an estimated 4200 and 700 t of food, respectively, each year.     

Development of visual species identification in ducklings: What is the role of imprinting?

The phenomenon of imprinting (a rapid form of exposure learning) is widely presumed to underlie the formation of normal, species-typical social preferences in precocial birds. To determine whether this is in fact the case, 24-h-old domestic and semi-wild mallard ducklings (Anas platyrhynchos) were allowed to follow a stuffed hen of one of three sympatric waterfowl species for 20 min. The models used were mallard, redhead (Aythya americana), and pintail (Anas acuta) hens. When later tested for their preference for the familiar hen in simultaneous choice tests with one of the other two stuffed models, only those birds trained with the Mallard and tested with the Mallard and Pintail models (designated the Mallard versus Pintail group) showed a preference for the familiar model. (That preference was shown by both domestic and semi-wild ducklings.) In none of the other three groups (Mallard versus Redhead, Redhead versus Mallard, and Pintail versus Mallard) was the imprinting procedure effective in producing a preference for the familiar model. When other ducklings were similarly trained with either the Mallard model, a red-and-white-striped box, or a green styrofoam ball, a preference for the familiar model was found in all four groups (Mallard versus Red Box, Red Box versus Mallard, Red Box versus Green Ball, and Green Ball versus Red Box). Increasing the length of the training period from 20 min to 2 h and to 24 h did not produce a preference for the familiar Mallard over the unfamiliar Redhead. These results raise some doubt that imprinting as currently conceived is the behavioural mechanism of visual species identification as it occurs in nature.     

The role of frequency modulation in controlling the response of mallard ducklings (Anas platyrhynchos) to conspecific distress calls

Three experiments examined the response of mallard ducklings to conspecific distress calls. In experiment 1, a synthetic call was constructed from a single distress note, by recording it on a digital disc and then using a software routine to regularly repeat this stored note with the average period (267 ms) of the original call. Ducklings were then tested for their tendency to inhibit their own distress vocalizations in response to either this synthetic call, the original call, or a constant-frequency tone mimic; they showed a significantly stronger inhibitory response to the synthetic call than to the tone mimic, but an even stronger response to the original call. The former result indicated that the synthetic call was an effective stimulus, and suggested that some aspect of the frequency modulation found in distress notes is required to evoke the normal duckling inhibitory response. The latter result further suggested that the acoustic variability found in the original call, but not the synthetic call, may be of importance for controlling duckling behaviour. Experiment 2 demonstrated that several other minor differences between the synthetic call and original call (number of notes per call and the digital recording of the synthetic call) could not account for the difference in duckling response to these two calls. Finally, in experiment 3, two additional synthetic stimuli were constructed from the digitized note, by first excising either the initial (front-chop) or terminal (rear-chop) frequency modulation found in each distress note, then creating amplitude envelopes for these new notes similar to that of the unaltered note, and finally repeating these notes to form calls with the same note period as the original call. The ducklings tested with the synthetic normal-note call and synthetic front-chop call showed a significantly stronger inhibitory response than the ducklings tested with the synthetic rear-chop call and the tone mimic. These results indicate that the terminal descending frequency sweep is an important feature of distress notes for triggering the response of ducklings to conspecific distress calls.     

Of Ducklings and Turing Machines: Interactive Playbacks Enhance Subsequent Responsiveness to Conspecific Calls

Distress calls of mallard ducklings consist of a highly stereotyped series of notes. When two ducklings are simultaneously separated from the brood, they characteristically call in alternation. Each bird inhibits its calls while the other is vocalizing, thus preventing masking and facilitating localization by the hen. I examined whether exposure of ducklings to calls presented in a naturalistic alternating pattern affected subsequent responsiveness to them. Individual ducklings were exposed to either 40 s or 80 s of computer-controlled distress call playbacks, using an algorithm that mimicked the behavior of another duckling. Calls were presented only when the subject was silent and ended as soon as it began to vocalize. Each of these ducklings was paired with a ‘yoked’ control. Birds in these control groups experienced exactly the same pattern of playbacks as the ‘interactive’ birds, but the stimuli had no consistent relationship to their own vocal behavior. When the same calls were played back 24 h later, in a fixed pattern that was independent of the ducklings' behavior, birds that had received 80 s of prior interactive exposure were significantly more responsive than both their yoked controls and birds receiving only 40 s of such playbacks. This result suggests that interactive vocal experience, characteristic of natural communication, affects the subsequent perceptual sensitivity of ducklings.     

The effects of pre-test conditions on social facilitation of drinking in ducks

The drinking and sieving of Khaki Campbell ducklings have been used as suitable behaviour patterns with which to study the social interactions in flock-living birds. Duckling from four-bird flocks were deprived of water for 3 hr, either in isolation or in groups of four. When the flocks were allowed access to water it was found that the isolated ducklings drank less than the non-isolated ducklings. Whilst both deprived and non-deprived birds engaged in sieving activity during the test, the sieving movements of the non-deprived birds were of longer duration than those of the deprived birds. Pre-test isolation of flock members was also shown to increase the duration of sieving movements. Re-introducing the isolated ducklings to each for the last 5 min of deprivation failed to eliminate the difference in either the drinking or the sieving behaviour between the isolated and non-isolated birds. The difference in drinking, but not sieving, could be eliminated by reuniting the birds for the last 30 min of deprivation. The disruption of flock ‘cohesion’ may lead to the failure of the mechanism of social facilitation despite a similar motivational condition in all flock members.     

鸭疫里默氏菌DnaK、OmpA和OmpA-DnaK蛋白的免疫原性

【背景】鸭疫里默氏菌(Riemerella anatipestifer,RA)可引起鸭等多种禽类败血症和浆膜炎,给禽养殖业造成严重经济损失。蛋白疫苗是预防RA感染的重要策略之一。目前,有关RA重组蛋白免疫原性报道较少,且其应用也受到单一蛋白抗原诱导的特异性免疫反应不足的限制。【目的】探究分子伴侣DnaK、外膜蛋白A (outer membrane protein A,OmpA)和OmpA-DnaK蛋白疫苗在鸭体内诱导的免疫应答,评估其免疫原性,为RA疫苗抗原研发提供依据。【方法】克隆DnaK和OmpA基因并分别与pET-32a(+)载体相连,利用限制性酶切位点Nco I和Bam H I将OmpA连接至DnaK基因上游,经原核表达和纯化制得重组蛋白DnaK、OmpA和OmpA-DnaK。3种重组蛋白分别皮下免疫雏鸭2次,检测其血清抗体滴度、淋巴细胞增殖和细胞因子(IL-2和IL-4)水平;以RA-GH5肌肉注射攻毒,检查其组织病理学变化及免疫保护率。【结果】成功表达了DnaK、OmpA和OmpA-DnaK重组蛋白,分子量分别约为90、60和130 kDa。3种蛋白疫苗均能诱导宿主产生体液...     

Effects of radiotransmitters and plasticine bands on Mallard duckling survival

ABSTRACT Individual markers are essential for measuring survival rates, but few reliable techniques exist for marking young waterfowl. We banded 572‐d‐old Mallard (Anas platyrhynchos) ducklings from 85 broods with plasticine‐filled leg bands in 2006–2007 and marked 82 hatchling Mallards from 43 broods with 1.8‐g back‐mounted prong‐and‐suture transmitters in 2006. We compared survival probabilities of marked ducklings and 621 unmarked ducklings from 110 broods where only the female was radio‐marked using the nest survival module in Program MARK. The best‐supported model recognized deleterious effects of both radiotransmitters (β=?0.82, 85% CI =?1.32 to ?0.33) and plasticine bands (β=?0.29, 85% CI =?0.55 to ?0.03). Cumulative survival to 30 d of age for unmarked ducklings averaged 0.22 (process variation; σ= 0.11) in 2006 and 0.20 (σ= 0.11) in 2007, whereas 30‐d survival of banded ducklings during these 2 yr was 0.14 (σ= 0.09) and 0.13 (σ= 0.09), respectively. Radio‐marked ducklings averaged 0.04 (σ= 0.03) cumulative survival in 2006. Although capturing ducklings after they leave nests is not always possible, post hoc analysis showed that marker effects decreased with duckling age and waiting until ducklings were at least 4 d old before marking would have negated these effects. Because marking hatchling Mallards with either radiotransmitters or plasticine bands negatively impacted their survival, we do not recommend these marking techniques for newly hatched ducklings.     

Spatial structure and parental aggression in eider broods

The spatial position of young animals within a brood affects their survival, so that marginal individuals are at greater risk of predation. Spatial brood structuring may be caused by differences in offspring size, age, hunger, or active parental manipulation through aggression. Nepotistic manipulation of brood structure would confer fitness benefits for parents accepting nondescendant young. However, insufficient kin recognition has often been considered to preclude such nepotism in birds, particularly in precocial waterfowl. We explored the spatial structure of ducklings within broods of eiders, Somateria mollissima, a seaduck with frequent brood amalgamation. We compared the distribution of ducklings of different origin relative to reference females whose kinship to the ducklings was known. We also observed female aggression towards ducklings, to evaluate the role of parental manipulation of brood structure. We found a nonrandom distribution of ducklings within broods; a female's own young were on average closer to her than unrelated young were. We also found evidence for parental nepotism: whether the brood contained unrelated young was the strongest predictor of female aggression towards ducklings. The spatial position, hatch weight and relative size of ducklings showed no significant correlations with each other, suggesting that active parental manipulation may be needed to explain the observed spatial structure. Our study conflicts with previous anecdotal evidence suggesting that brood amalgamation in eiders results in the disintegration of parent-offspring bonds, preventing parental exploitation of nondescendant young. It also opens up the possibility that the spatial position of ducklings depends on their mother's status in the female dominance hierarchy. Copyright 2003 The Association for the Study of Animal Behaviour. Published by Elsevier Ltd. All rights reserved.