Food supplementation by an invasive fleshy-fruited shrub sustains body condition of a native frugivorous bird during winter.

Systemic infusion of exogenous ghrelin in male broiler chickens (Gallus gallus domesticus). The effect of pulse frequency, doses, and ghrelin forms on feed intake, average daily gain, corticosterone, and growth hormone concentrations

Body condition is a frequently used physiological indicator of avian health and can be affected by an array of environmental variables. Although a number of studies have investigated the specific effects of individual weather variables on body condition in birds, few have analyzed the effects of both temperature and precipitation within the context of an extreme weather event such as hurricanes. In this study, we examined the relationship between breeding‐season body condition and daily maximum temperature, daily minimum temperature, and monthly total precipitation for three passerine bird species at the Welder Wildlife Refuge near Rockport, Texas. We also evaluated yearly changes in body condition over a 12‐year period for northern cardinals (Cardinalis cardinalis), painted buntings (Passerina ciris), and white‐eyed vireos (Vireo griseus), focusing on the extreme precipitation event of Hurricane Harvey, which caused heavy localized flooding. We found that body condition declined with average daily minimum and maximum temperatures, while precipitation had varied, species‐specific effects in the three species analyzed. Our results also suggest that northern cardinals experienced a notable reduction in average body condition in the 2 years following Hurricane Harvey. Taken together, we conclude that short‐term precipitation and temperature drivers can be important correlates of body condition in songbirds and that severe weather events may reduce body condition in some bird species.

Summary Selection of prey in poor body condition allegedly is a widespread phenomenon in predator–prey systems. Yet, it remains unclear to what extent such selection reflects impeded prey escape ability due to severe malnutrition and/or state‐dependent risk taking following lesser changes in prey body condition. In systems where prey food availability is adequate, few individuals should be severely malnourished and thus condition‐sensitive predation should be related principally to changes in nutritional status that occur irrespective of an individual's absolute body condition. I studied predation in snowshoe hares ( Lepus americanus , Erxleben) when food was abundant, to test the prediction that change in body condition would contribute, more than would absolute body condition, to vulnerability to predation. Hares ( n = 618) were radio‐marked and monitored for survival while body condition was indexed during bimonthly livecaptures. A subsample of animals ( n = 36) was equipped with motion‐sensitive transmitters and activity patterns were examined in relation to the body condition index and vulnerability to predation. Manipulation of hare nutritional status via food supplementation improved hare body condition but did not affect vulnerability to predation; reduction of nematode parasite numbers did not improve hare condition but reduced predation among female hares. Reproductive status affected predation in both sexes, with recently pregnant females and non‐scrotal males being less vulnerable to predation. Heavier males also tended to experience lower predation rates. Predation rates for both female and male hares were higher among individuals having recently experienced condition deterioration but not among animals considered to be in poor absolute condition. Yet, the parameter representing change in condition was the last to enter survival models, indicating a relatively modest effect of this factor on hare vulnerability to predation. Mammalian but not avian predators tended to kill hares in declining condition, and hare activity patterns were not correlated either to change in condition or to survival. These findings indicate that nutritional status may influence vulnerability to predation even when food is abundant, but that such effects occur indirectly through changing body condition. This implies that hares are likely to forage in a risk‐prone manner when subject to worsening condition.

Severe weather events are increasing worldwide because of climate change. To cope with severe weather events, vertebrates rely on the stress response which is activated by the hypothalamic-pituitary adrenal (HPA) axis to adjust physiology and behavior. Previous studies have detailed changes in baseline concentrations of the stress hormone corticosterone during a single storm event, but little data exists on how stress physiology and body condition are adjusted as the storm progresses across multiple days. This represents a serious gap in our understanding of how birds respond physiologically over the duration of a storm. We documented arctic snowstorms that occurred over five consecutive years that were endured by Lapland longspurs (Calcarius lapponicus; 2012–2016) and in three consecutive years by white-crowned sparrows (Zonotrichia leucophrys gambelii; 2014–2016). Data were collected on storm-free days, during snowstorms ranging in length from 1 to 3 days, and the day immediately following a snowstorm. The specific aims were to understand how stress physiology, measured at baseline and in response to restraint handling, and body condition changed over multiple days of the storm, and if these responses were consistent across years. Snowstorms did not affect baseline corticosterone concentrations for either species except for female Lapland longspurs and male white-crowned sparrows in 2014. Lapland longspurs, regardless of sex, increased stress-induced (restraint handling) corticosterone in response to snowstorms in all years but 2013, which was characterized by unusually harsh conditions. Both sexes of White-crowned sparrows showed a significant increase in the stress-induced levels of corticosterone during snowstorms in one of the three years of the study. Stress-induced corticosterone concentrations were only different across each day of the storm in one year of the study for Lapland longspurs. Changes in fat and body mass were not uniform across years, but measurable increases in fat stores and body mass were detected in males of both species during the first day of a snowstorm with declines typically occurring by the second day. Our study showed that severe weather events often caused rapid increases in HPA axis activity and body condition, but these profiles are likely dependent upon ecological and environmental context within the breeding season.

BackgroundClimate change potentially has important effects on distribution, abundance, transmission and virulence of parasites in wild populations of animals.Methodology/Principal FindingHere we analyzed paired information on 89 parasite populations for 24 species of bird hosts some years ago and again in 2010 with an average interval of 10 years. The parasite taxa included protozoa, feather parasites, diptera, ticks, mites and fleas. We investigated whether change in abundance and prevalence of parasites was related to change in body condition, reproduction and population size of hosts. We conducted analyses based on the entire dataset, but also on a restricted dataset with intervals between study years being 5–15 years. Parasite abundance increased over time when restricting the analyses to datasets with an interval of 5–15 years, with no significant effect of changes in temperature at the time of breeding among study sites. Changes in host body condition and clutch size were related to change in temperature between first and second study year. In addition, changes in clutch size, brood size and body condition of hosts were correlated with change in abundance of parasites. Finally, changes in population size of hosts were not significantly related to changes in abundance of parasites or their prevalence.Conclusions/SignificanceClimate change is associated with a general increase in parasite abundance. Variation in laying date depended on locality and was associated with latitude while body condition of hosts was associated with a change in temperature. Because clutch size, brood size and body condition were associated with change in parasitism, these results suggest that parasites, perhaps mediated through the indirect effects of temperature, may affect fecundity and condition of their hosts. The conclusions were particularly in accordance with predictions when the restricted dataset with intervals of 5–15 years was used, suggesting that short intervals may bias findings.

Ovipositions in hens maintained under schedules of 16h light : 8h darkness (16L : 8D) or 8L: 16D were restricted to a 12h period of the day while in hens maintained on continuous light, ovipositions occurred at times throughout the whole of the 24h day. In hens maintained in continuous light a significant rise in the plasma concentration of corticosterone was observed 11-9h before ovulation/oviposition. In hens in 16L : 8D there was an increase in the concentration of corticosterone in the plasma during the first 1.5h of darkness which, under that schedule, coincides with the onset of the "open period" for the occurrence of the preovulatory release of LH. In hens ovulating the first egg of a sequence the rise in the secretion of corticosterone was only transient and levels fell as preovulatory concentrations of LH rose to a peak. However, in hens undergoing an ovulation late in a sequence or in those not expected to ovulate, the concentration of corticosterone in the plasma continued to rise to attain a maximal concentration 8h later. In hens maintained in 8L : 16D there was a tendency for the concentration of corticosterone in the plasma to increase at the beginning of the open period, 4 h after the onset of darkness, though this rise was much smaller than that observed at the beginning of the open period of hens on 16L : 8D. A further, more pronounced, increase in concentration of corticosterone was observed between 11 and 15h after the onset of darkness. It is suggested that the rise in the concentration of corticosterone at 11-9 h before ovulation in hens in continuous light reflects the beginning of an open period with a free-running circadian periodicity of 26-27 h.

Ecological theory suggests that demographic responses by populations to environmental change vary depending on whether individuals inhabit central or peripheral regions within the species’ geographic range. Here, we tested this prediction by comparing a population of ringed seals Pusa hispida located at high latitudes as part of their core range (core) with a population located at the southern extremity of their range (peripheral). First, we compared the two regions’ environmental trends in timing of sea‐ice breakup and freeze‐up, open‐water duration and the North Atlantic Oscillation (NAO). We found that the core region shifted to progressively warmer conditions in the early 1990s; whereas, in the peripheral region, the warming trend shifted in 1999 to one with no warming trend but high inter‐annual variability. Next, we examined how body condition, inferred from blubber depth, responded to temporal changes in sea‐ice and climatic variables – variables that have been shown to influence ringed seal demography. Core seals displayed minimal seasonal changes in body condition; whereas peripheral seals displayed a 20–60% amplitude seasonal change in body condition with a phase shift to earlier initiation of fat accumulation and loss. Finally, we tested for interannual differences and found that both core and peripheral seals responded similarly with decreased body condition following more positive NAO. Environmental variables influenced body condition in opposite directions between the two regions with core seals declining in body condition with later spring breakup and shorter open‐water duration, whereas peripheral seals showed opposite relationships. Seals living at the core likely benefit from an evolved match between adaptation and environmental variation resulting in dampened seasonal and interannual fluctuations in body condition. Knowledge of how different populations respond to environmental change depending on geographic location within a species range can assist in anticipating population specific responses to climate warming.

Primates display varying degrees of behavioral flexibility that allow them to adjust their diet to temporal changes in food availability. This trait might be critical for the survival of folivorous-frugivorous species inhabiting small forest fragments, where the availability of food resources tends to be lower than in large fragments and continuous forests. However, the scarcity of studies addressing this issue hampers our understanding of the adaptive behaviors that favor the survival of these primates in low-quality habitats. We conducted a 36-mo study testing the hypothesis that brown howler monkeys (Alouatta guariba clamitans) are able to adjust their diet in response to local and seasonal changes in resource availability. We compared the diet of six free-ranging groups inhabiting three small (<10 ha) and three large (>90 ha) Atlantic forest fragments in southern Brazil and estimated the temporal availability of their top food species (i.e., those species that together contribute ≥80% of total feeding records). We found that brown howlers exploited similarly rich diets in small (45, 54, and 57 plant species) and large (48, 51, and 56 species) fragments. However, intermonth diet similarity was higher for groups in small fragments, where howlers also fed on plant items from nine alien species. Fruits and leaves were the most consumed plant items in both small (42% and 49% of feeding records, respectively) and large (51% and 41%, respectively) fragments. The consumption of young leaves was higher in small than in large fragments, whereas the consumption of other plant items did not show a pattern related to fragment size. Regarding the contribution of growth forms as food sources, only the exploitation of palms showed a pattern related to fragment size. Palms contributed more to the diet of groups inhabiting large fragments. The availability of seasonal food items–ripe fruits and young leaves–influenced their consumption in both habitat types. Therefore, brown howlers cope with local and seasonal fluctuations in food availability by opportunistically exploiting resources. We believe that this feeding flexibility is a key component of the phenotypic plasticity that enables howlers to thrive in disturbed habitat patches, where periods of scarcity of preferred foods shall be more common.

Relationship between plasma and tissue corticosterone in laying hens (Gallus gallus domesticus): implications for stress physiology and animal welfare

We investigated the seasonal pattern of changes in body condition of breeding black‐legged kittiwakes Rissa tridactyla in Svalbard (79°N) to evaluate whether changes in body condition were a consequence of the energetic demands of breeding (the reproductive stress hypothesis) or of voluntary anorexia to attain lower flight costs during chick rearing (the programmed anorexia hypothesis). Adult body condition was recorded from early egg laying to fledging and was examined in relation to date (relative to hatching), sex, parental time‐budget, brood size and reproductive success. To distinguish between the two hypotheses we evaluate whether the reduction in body condition occurred during or ahead of the energetically most demanding part of the chick‐rearing period. We combine our results on changes in body condition and time‐budget with published information on field metabolic rate (FMR) and chick energy requirements from studies in the same colony. Our calculations of adult energy requirements and energy intakes indicate that the first part of the chick‐rearing period was energetically the most demanding period, because adult energy requirement per hour spent off the nest was highest in this period, and adults were time constrained because of the need for 24‐h brooding of the chicks. During the incubation period female body condition increased slightly, but significantly, while male body condition was stable. During the first part of the chick‐rearing period, female and male body condition decreased by 14.8% and 8.4%, respectively. During the second part of the chick‐rearing period, both male and female body condition remained stable. The reductions in body condition occurred during the phase which was suggested to be the energetically most demanding part of the chick‐rearing period, thus supporting the reproductive stress hypothesis. Parental body condition during the incubation period was positively related to the probability of successfully fledging young, providing additional support for the reproductive stress hypothesis.

Ecological disturbances are discrete events that alter or transform the physical, chemical, or biological characteristics of ecosystems. Disturbance can cause animal populations to decline and, according to the risk-disturbance hypothesis and population collapse framework, these declines can be predicted by declines in animal body condition. However, no research has empirically examined the general relationship between body condition and abundance, nor their relationship in response to disturbance. We used a combined dataset representing 33 studies and > 42,000 observations of 75 species from Australia, New Zealand, Spain and the United States of America to test predictions relating to the relationship between reptile body condition and abundance. We first investigated the relationship at the site level and then used meta-analytical models to test whether populations showed linked changes in abundance and body condition in response to disturbance. We further tested whether key environmental and species traits influenced this relationship and whether there was a time-lagged effect of body condition responses on abundance. We found a positive relationship between mean reptile body condition and abundance at the site level. However, the relationship was largely lost when investigating population responses to disturbance. As such, our results provided no support for the risk-disturbance hypothesis and limited support for the population collapse framework. Therefore, the impacts of disturbance on reptile body condition cannot be assumed to reflect or predict abundance responses. We provide a new conceptual framework that shows how disturbances can modify or uncouple the relationship between abundance and body condition by influencing underlying drivers, such as predation, competition and resource availability. Monitoring programs that infer population impacts based on changes in body condition should first confirm the relationship between these two variables in the relevant study system.

Essential oils are being introduced in swine diets as an alternative to antibiotic usage. The objectives of this preliminary study were to determine the effects of Agolin-Pig, a combination of micro-encapsulated essential oils, on sow feed intake, sow health and body condition, piglet growth performance, and future evaluation of microbiota structure. The experimental design consisted of 26 sows randomly allotted to either control (n = 13) or treatment groups (n = 13). Both groups consumed diets that met NRC standards (NRC, 2012), with the treatment group receiving 200 ppm of Agolin-Pig in a premix made in-house for 2 weeks pre-farrowing, and throughout farrowing and lactation. Sow average daily feed intake (ADFI) and piglet average daily gain (ADG) were recorded and calculated to monitor effects of Agolin-Pig. Sow body weights, body condition scores (BCS), and Knauer Sow Caliper measurements were collected at the start of the trial, 1-week post-farrowing, and at weaning to determine the change in sow body condition during lactation. All data were analyzed using PROC Mixed procedure in SAS 9.4 (Cary, North Carolina) with treatment, week, and parity (P1 vs P≥2) as main effects, repeated measures of sows and piglets, and number nursed used as a covariate where appropriate. All sows significantly increased ADFI (P = 0.0001) between weeks 1, 2, and 3 as expected during lactation, regardless of treatment. There was no significant impact of Agolin-Pig treatment on sow ADFI and piglet ADG. Piglets significantly increased ADG each week for 3 weeks (P ± 0.0001). During lactation, Agolin-Pig significantly reduced the loss of body condition as measured by the caliper (P = 0.028). Calipers are proven to detect changes in body condition more accurately than visual, subjective BCS, indicating that the caliper identifies a reduction in body condition that may have been missed by BCS or weight change altered by lactation. The gilts in the control group tended to show a reduction in BCS compared with sows in the control group (P = 0.074). In comparison, there was no significant difference in BCS between gilts and sows in the Agolin-Pig treated group suggesting that Agolin-Pig is effective at reducing the loss of BCS in gilts during lactation. Current analysis of fecal microbiota and milk composition may give greater insight on the effects of Agolin-Pig on sows. Overall, Agolin-Pig was effective at reducing the loss of body condition during lactation, as measured by the caliper. Additionally, Agolin-Pig tended to reduce the difference in loss of body condition of gilts compared with the control group. The findings of this pilot study warrant future studies with greater sample size to determine the efficacy of Agolin-Pig on reducing body condition loss and impacting other performance measures during lactation in sows.

Reproductive seasonality in female goats adapted to a subtropical environment persists independently of food availability

Correct managing of dam body condition during the winter period results in increased number of live born kits. So far, male body condition has not been related to male reproduction success. We therefore wanted to study whether the male body condition, visually graded using a 1 to 9 point scale, has influence on re-production results. Body condition of 6500 mink males of the brown colour type from 12 farms were scored in December, January, February and March in the winter period 2011/2012. The data will be used to seek answers for the following questions: (1) Has male body condition, or changes in body condition at specific point in time influence on mating willingness (mating willingness defined as the number of successful mating’s), percentage of barren dams and litter size? (2) Have changes in male body condition in specific periods influence on number of mating’s, percentage of barren dams and litter size? (3) What would be the optimal body condition development for mink males from December to medio March in relation to reproduction results?

PDF HTML阅读 XML下载 导出引用 引用提醒 食物限制对黑线仓鼠免疫功能的影响 DOI: 10.5846/stxb201305241171 作者: 作者单位: 曲阜师范大学生命科学学院,曲阜师范大学 作者简介: 通讯作者: 中图分类号: 基金项目: 国家自然科学基金(31070332,31370427);山东省自然科学基金(ZR2013CM019);曲阜师范大学博士启动基金(bsqd20100204) Effect of food restriction on immune function in the striped hamster (Cricetulus barabensis) Author: Affiliation: College of Life Sciences,Qufu Normal University,Qufu,273165,Shandong Province Fund Project: 摘要 | 图/表 | 访问统计 | 参考文献 | 相似文献 | 引证文献 | 资源附件 | 文章评论 摘要:温带地区小型哺乳动物经常面临着食物资源的波动。食物对动物的免疫功能具有重要影响。将19只成年雄性黑线仓鼠(Cricetulus barabensis)随机分为自由取食组(n=9)和限食组(n=10)。注射植物血球凝集素(PHA)来测定细胞介导的免疫反应,用匙孔血蓝蛋白(KLH)免疫动物,然后测定抗KLH抗体的浓度以反映其体液免疫功能。旨在检验食物限制是否会抑制黑线仓鼠的细胞免疫和体液免疫功能。结果发现,与对照组相比,限食组黑线仓鼠具有较低的体重、体脂、脾脏鲜重、血清瘦素水平、免疫球蛋白IgG和IgM浓度。而限食对胸腺鲜重、白细胞数、皮质酮水平以及PHA反应没有显著影响。结果表明黑线仓鼠免疫系统的不同成分对限食反应存在差异,在食物资源短缺时,黑线仓鼠防御细胞外病原体的能力降低,从而导致生存能力的下降。 Abstract:The immune system protects animals against environmental pathogens, and hence it plays an important role in their survival and fitness. However, immune function is influenced by many factors including food availability. Small mammals in the temperate zone often face fluctuations in food availability, which is important to their survival. Changes in food availability may have a great influence on an animals' immunity. Some investigators have examined the effect of reduced food availability (i.e., food restriction) on the immune function in small rodents, but their results are often inconsistent. Food restriction could depress, enhance or have no effect on immunity in different species. In order to clarify the discrepancy between results, the striped hamster (Cricetulus barabensis) was used to examine the effect of food restriction on its immune function. The striped hamster is a major pest rodent in northern China. It is granivorous, nocturnal and feeds mainly on plant stems and leaves during summer and forages crop seeds in winter. The climate is arid and characterized by warm and dry summers and cold winters. Thus, the species experiences great seasonal fluctuations in temperature, photoperiod as well as food quality and availability. The question we focused on in the present study was how the immune function would vary in the face of reduced food availability for hamsters. Nineteen adult male hamsters were randomly divided into the fed ad libitum group (Fed, n=9) and food restricted group (FR, n=10) (90% of baseline food intake). The course of food restriction was 21 days. Hamsters were injected with phytohaemagglutinin (PHA) and keyhole limpet haemocyanin (KLH) solution to assess cellular and humoral immunity, respectively. Our goal was to test whether food restriction would suppress cellular and humoral immunity in striped hamsters. Body mass in the FR group decreased significantly after 21 days of food restriction, whereas body mass in the Fed group did not change significantly. Body mass in the FR group was significantly lower than that of the Fed group after 10 days of food restriction. Food restriction significantly reduced perirenal fat, perirenal fat content, retroperitoneal fat, total body fat, and wet spleen mass in the FR group compared with the Fed group. However, it had no significant effect on the wet thymus mass or white blood cells. Immunoglobulin (Ig) G and IgM concentrations were reduced significantly in the food restricted hamsters in contrast with the Fed control group, which indicated the suppressive role of food restriction on humoral immunity. PHA response did not differ between the two groups, suggesting cellular immunity was not influenced by food restriction. Food restricted hamsters had significantly lower serum leptin levels than that of the control group, while corticosterone levels were not affected by food restriction. Taken together, our results suggest that different components of the immune system respond differently to food restriction in striped hamsters. Humoral immunity was suppressed in food restricted hamsters, which might be due to their lower body fat mass and lower leptin levels. In the face of food shortage, striped hamsters might be more prone to extracellular pathogens and their survival capability would decrease. 参考文献 相似文献 引证文献