scholarly journals Diet and Preparation for Spring Migration in Captive Hermit Thrushes (Catharus Guttatus)

The Auk ◽  
2003 ◽  
Vol 120 (2) ◽  
pp. 323-330
Author(s):  
Jennifer A. Long ◽  
Philip C. Stouffer
Keyword(s):  
Body Mass ◽  
Food Choice ◽  
Migratory Birds ◽  
Subcutaneous Fat ◽  
Spring Migration ◽  
Migratory Activity ◽  
Fat Reserves ◽  
Significant Difference ◽  
Catharus Guttatus ◽  
Fat Score

Abstract Seasonal changes in food choice by migratory birds often reflect changes in relative food abundance and increased energetic demand. Hermit Thrushes (Catharus guttatus) in southeastern Louisiana are highly frugivorous during winter but forage exclusively on arthropods just prior to spring migration. We hypothesized that this switch to an exclusively arthropod diet would lead to an increase in fat reserves compared to a frugivorous diet, and that fat birds would initiate migration sooner and display more migratory activity than lean birds. We tested these hypotheses on captive Hermit Thrushes maintained on either an arthropod only diet or a mixed fruit and arthropod diet and measured changes in fat score, body mass, and nocturnal migratory activity (Zugunruhe) from February to April 2000. We found that the arthropod-only treatment led to greater body mass and greater amounts of subcutaneous fat than the mixed fruit and arthropod treatment by the third week of the experiment. Despite those differences, body mass was not correlated with intensity of Zugunruhe. We also did not find a significant difference in intensity or onset of Zugunruhe between treatments. We concluded that because Hermit Thrushes are short-distance migrants, large fat reserves are not crucial for their migration. Consequently, fruit and arthropods appear to be equivalent with respect to migratory behavior.

scholarly journals Body Condition and Fat Score in Local and Passage Populations of the Great Reed Warbler (Acrocephalus arundinaceus) During the Spring Migration in NE Bulgaria

Ring ◽  
2005 ◽  
Vol 27 (2) ◽  
pp. 137-143 ◽  
Author(s):  
Pavel Zehtindjiev
Keyword(s):  
Body Mass ◽  
Body Condition ◽  
Spring Migration ◽  
The Body ◽  
Great Reed Warbler ◽  
Acrocephalus Arundinaceus ◽  
Reed Warbler ◽  
Field Methods ◽  
Field Station ◽  
Fat Score

Body Condition and Fat Score in Local and Passage Populations of the Great Reed Warbler (Acrocephalus arundinaceus) During the Spring Migration in NE Bulgaria The fat level and the body mass of local Great Reed Warblers in the Kalimok Field Station, NE Bulgaria (41°00'N, 26°26'E) were compared with those of passing birds. During the springs of 1998-2004, 591 individuals of this species were mist-netted and handled according to the guidelines in the Manual of Field Methods (ESF project) and to the South-East European Bird Migration Network (SEEN) standards. As local birds we identified 60 individuals caught at least twice in different seasons. The means of the fat score and the body mass calculated for the local birds and for the passing Great Reed Warblers were similar. Also, the time of the local birds arrival and the passage of the species in the region studied coincided. Therefore, we suggest that the southern and northern populations have equal potentials for realization of their migratory state and birds from southern populations could spread in spring to the north, being an important interregional gene flow in Great Reed Warblers.

scholarly journals Effects of habitat edges on vegetation structure and the vulnerable golden-brown mouse lemur (Microcebus ravelobensis) in northwestern Madagascar

BMC Ecology ◽  
2020 ◽  
Vol 20 (1) ◽  
Author(s):  
Bertrand Andriatsitohaina ◽  
Daniel Romero-Mujalli ◽  
Malcolm S. Ramsay ◽  
Frederik Kiene ◽  
Solofonirina Rasoloharijaona ◽  
...  
Keyword(s):  
Body Mass ◽  
Edge Effects ◽  
Vegetation Structure ◽  
Species Abundance ◽  
Tree Height ◽  
Logistic Function ◽  
Study Region ◽  
Large Trees ◽  
Significant Difference ◽  
Vegetation Parameters

Abstract Background Edge effects can influence species composition and community structure as a result of changes in microenvironment and edaphic variables. We investigated effects of habitat edges on vegetation structure, abundance and body mass of one vulnerable Microcebus species in northwestern Madagascar. We trapped mouse lemurs along four 1000-m transects (total of 2424 trap nights) that ran perpendicular to the forest edge. We installed 16 pairs of 20 m2 vegetation plots along each transect and measured nine vegetation parameters. To determine the responses of the vegetation and animals to an increasing distance to the edge, we tested the fit of four alternative mathematical functions (linear, power, logistic and unimodal) to the data and derived the depth of edge influence (DEI) for all parameters. Results Logistic and unimodal functions best explained edge responses of vegetation parameters, and the logistic function performed best for abundance and body mass of M. ravelobensis. The DEI varied between 50 m (no. of seedlings, no. of liana, dbh of large trees [dbh ≥ 10 cm]) and 460 m (tree height of large trees) for the vegetation parameters, whereas it was 340 m for M. ravelobensis abundance and 390 m for body mass, corresponding best to the DEI of small tree [dbh < 10 cm] density (360 m). Small trees were significantly taller and the density of seedlings was higher in the interior than in the edge habitat. However, there was no significant difference in M. ravelobensis abundance and body mass between interior and edge habitats, suggesting that M. ravelobensis did not show a strong edge response in the study region. Finally, regression analyses revealed three negative (species abundance and three vegetation parameters) and two positive relationships (body mass and two vegetation parameters), suggesting an impact of vegetation structure on M. ravelobensis which may be partly independent of edge effects. Conclusions A comparison of our results with previous findings reveals that edge effects are variable in space in a small nocturnal primate from Madagascar. Such an ecological plasticity could be extremely relevant for mitigating species responses to habitat loss and anthropogenic disturbances.

scholarly journals OP0220 ASSESSING THE EFFECT OF INCREASED BODY MASS INDEX ON RESPONSE TO TNF INHIBITORS IN ESTABLISHED RHEUMATOID ARTHRITIS: RESULTS FROM THE METEOR DATABASE

2020 ◽  
Vol 79 (Suppl 1) ◽  
pp. 137.1-137
Author(s):  
M. Dey ◽  
S. S. Zhao ◽  
R. J. Moots ◽  
R. B. M. Landewé ◽  
N. Goodson
Keyword(s):  
Rheumatoid Arthritis ◽  
Body Mass Index ◽  
Body Mass ◽  
Personalised Medicine ◽  
Normal Weight ◽  
Sensitivity Analyses ◽  
Established Rheumatoid Arthritis ◽  
Eular Response ◽  
Significant Difference ◽  
Das28 Remission

Background:Rheumatoid arthritis (RA) is associated with increased body mass index (BMI)- 60% of patients are either overweight or obese. Obesity in RA has been shown to predict reduced response to biologic therapy including tumour-necrosis-factor inhibitors (TNFi) [1]. However, it is not clear whether increased BMI influences response to all TNFi drugs in RA.Objectives:1.To explore whether BMI is associated with response to TNFi in patients with established rheumatoid arthritis (estRA), including those newly-starting on these drugs.Methods:Participants with estRA (>1year since diagnosis) taking biologic medications, registered on METEOR (international database of RA patients), 2008-2013, were included. EULAR response, DAS28 remission (including components), and treatment regimens were recorded at baseline, 6, and 12 months. WHO definitions of overweight (BMI≥ 25) and obese (BMI≥30) were explored as predictors of TNFi response (good EULAR response and DAS28 remission) using normal BMI as comparator. Logistic and linear regression models (controlling for age, gender, smoking, and baseline outcomes) and sensitivity analyses were performed. Subgroup analyses were performed for grouped TNFi and individual TNFi (infliximab, IFX; adalimumab, ADA; etanercept, ETN).Results:247 patients with estRA were taking a biologic at 6 months, and 231 patients were taking a biologic at 12 months. Obese patients taking any biologic were significantly less likely to achieve DAS28 remission (OR 0.33 [95%CI 0.12-0.80]) or good EULAR response (OR 0.37 [95%CI 0.16-0.81]) after 6 months, compared to those of normal BMI; this was also demonstrated in those co-prescribed methotrexate (DAS28 remission: OR 0.23 [95%CI 0.07-0.62]; good EULAR response: OR 0.39 [95%CI 0.15-0.92]). These associations did not remain statistically significant at the 12 months assessment.Regarding specific anti-TNF therapies, RA patients treated with monoclonal antibody (-mab) TNFis (IFX/ADA/ GOL) were significantly less likely to achieve good EULAR response at 6 months if they were obese RA (n=38), compared to those of normal weight (n=44) (OR 0.17 [95%CI 0.03-0.59]). A similar non-significant difference was demonstrated for DAS28 remission, and 12-month remission. Specifically, obese individuals were significantly less likely to achieve good EULAR response at 6 months with IFX (OR 0.09 [95%CI 0.00-0.61]; n=20), and significantly less likely to achieve DAS28 remission at 6 months when newly-starting ADA (OR 0.14 [95%CI 0.01-0.96]; n=17), compared to those of normal weight. There were no significant differences in remission outcomes between individuals of different BMI taking ETN. A small number of individuals stopped taking their respective biologic after 6months; reason for cessation was not recorded.Similar outcomes were seen in patients already established on anti-TNF therapy, with overweight and obese individuals less likely overall to be in DAS28 remission at all time points.Conclusion:In established RA, obesity is associated with reduced treatment response to -mab TNFi. No association between increased BMI and response to ETA was observed. Using BMI to direct biologic drug choice could prove to be a simple and cost-effective personalised-medicine approach to prescribing.References:[1]Schäfer M, Meißner Y, Kekow J, Berger S, Remstedt S, Manger B, et al. Obesity reduces the real-world effectiveness of cytokine-targeted but not cell-targeted disease-modifying agents in rheumatoid arthritis. Rheumatology. 2019 Nov 20.Disclosure of Interests:Mrinalini Dey: None declared, Sizheng Steven Zhao: None declared, Robert J Moots: None declared, Robert B.M. Landewé Consultant of: AbbVie; AstraZeneca; Bristol-Myers Squibb; Eli Lilly & Co.; Galapagos NV; Novartis; Pfizer; UCB Pharma, Nicola Goodson: None declared

Comparison of CrossFit Barbara and classic resistance trainings for the protection of strength performance during off-season in kickboxers

2020 ◽  
pp. 1-8
Author(s):  
Cebrail Gençoğlu ◽  
İlhan Şen
Keyword(s):  
Resistance Training ◽  
Body Mass ◽  
Body Fat ◽  
Bench Press ◽  
Body Fat Percentage ◽  
Fat Percentage ◽  
Strength Performance ◽  
Significant Difference ◽  
Before And After ◽  
Push Up

BACKGROUND: The inability of athletes to train or the decrease in the intensity and frequency of training may cause athletes to lose performance. Particularly in view of the current COVID-19 pandemic, maintaining strength outside the normal framework provides an advantage to athletes for the next competitions. OBJECTIVE: To compare the CrossFit Barbara which can be applied easily at home during the off-season or some situations such as the epidemic limitation to classic resistance training methods used to maintain the strength performance of national kickboxers. METHODS: Forty-three national kickboxers, CrossFit (CF, n= 22), and resistance training (RT, n= 21), participated in this study. While CF performed 20 pull-ups, 30 push-ups, 40 sit-ups, and 50 squat exercises, RT performed bench press, lat pull down, leg press, biceps curl, and triceps extension exercises twice per week for six weeks. Before and after the six weeks, the following variables were measured; body mass (BM) and body fat percentage (FP), VO2max, bench press (BP), squat (SQ), leg strength (LS), hand grip strength (HGS), pull-up, push-up and counter movement jump (CMJ). RESULTS: BP (p< 0.001, F= 41.125, ηp2= 0.501), SQ (p< 0.001, F= 26.604, ηp2= 0.394), LS (p< 0.001, F= 15.234, ηp2= 0.271), push-up (p< 0.001, F= 31.978, ηp2= 0.438) and pull-up (p< 0.001, F= 24.410, ηp2= 0.373) values changed significantly in group-time interaction between CF and RT groups, while there was no significant difference for the BM (p= 0.198, F= 1.715, ηp2= 0.040), Fat (p= 0.265, F= 1.279, ηp2= 0.030), HGS (p= 0.665, F= 0.190, ηp2= 0.005, CMJ (p= 0.054, F= 3.946, ηp2= 0.088) and VO2max (p=0.747, F= 0.106, ηp2= 0.003). Furthermore, according to the before and after study values, BP, SQ, LS, and CMJ decreased significantly (p< 0.05) while BM, FP, HGS, VO2max, pull-up and push-up variables did not in the CF (p> 0.05). In the RT, the pull-up and push-up variables decreased significantly (p< 0.05) while there was no significant difference for BP, SQ, LS, HGS, VO2max, body mass, body fat percentage and CMJ (p> 0.05). CONCLUSION: CF Barbara workout was more effective in maintaining strength endurance performances, and RT in maintaining maximum strength performances. According to the individual performance needs of athletes, reasonable training method can be used to prevent performance decrement in the strength domain.

scholarly journals Body mass index and clinical outcomes in patients with intracerebral haemorrhage: results from the China Stroke Center Alliance

2021 ◽  
pp. svn-2020-000534
Author(s):  
Zhentang Cao ◽  
Xinmin Liu ◽  
Zixiao Li ◽  
Hongqiu Gu ◽  
Yingyu Jiang ◽  
...  
Keyword(s):  
Body Mass Index ◽  
Hospital Mortality ◽  
Body Mass ◽  
Intracerebral Haemorrhage ◽  
Final Analysis ◽  
Normal Weight ◽  
Discharge Disposition ◽  
Increased Risk ◽  
Significant Difference ◽  
Stroke Center

Background and aimObesity paradox has aroused increasing concern in recent years. However, impact of obesity on outcomes in intracerebral haemorrhage (ICH) remains unclear. This study aimed to evaluate association of body mass index (BMI) with in-hospital mortality, complications and discharge disposition in ICH.MethodsData were from 85 705 ICH enrolled in the China Stroke Center Alliance study. Patients were divided into four groups: underweight, normal weight, overweight and obese according to Asian-Pacific criteria. The primary outcome was in-hospital mortality. The secondary outcomes included non-routine discharge disposition and in-hospital complications. Discharge to graded II or III hospital, community hospital or rehabilitation facilities was considered non-routine disposition. Multivariable logistic regression analysed association of BMI with outcomes.Results82 789 patients with ICH were included in the final analysis. Underweight (OR=2.057, 95% CI 1.193 to 3.550) patients had higher odds of in-hospital mortality than those with normal weight after adjusting for covariates, but no significant difference was observed for patients who were overweight or obese. No significant association was found between BMI and non-disposition. Underweight was associated with increased odds of several complications, including pneumonia (OR 1.343, 95% CI 1.138 to 1.584), poor swallow function (OR 1.351, 95% CI 1.122 to 1.628) and urinary tract infection (OR 1.532, 95% CI 1.064 to 2.204). Moreover, obese patients had higher odds of haematoma expansion (OR 1.326, 95% CI 1.168 to 1.504), deep vein thrombosis (OR 1.506, 95% CI 1.165 to 1.947) and gastrointestinal bleeding (OR 1.257, 95% CI 1.027 to 1.539).ConclusionsIn patients with ICH, being underweight was associated with increased in-hospital mortality. Being underweight and obese can both increased risk of in-hospital complications compared with having normal weight.

scholarly journals Clinical characteristics and longitudinal changes of patients with non-alcoholic fatty liver disease in 2 decades: the NAGALA study

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Takuro Okamura ◽  
Yoshitaka Hashimoto ◽  
Masahide Hamaguchi ◽  
Akihiro Obora ◽  
Takao Kojima ◽  
...  
Keyword(s):  
Body Mass Index ◽  
Liver Disease ◽  
Fatty Liver ◽  
Body Mass ◽  
Fatty Liver Disease ◽  
Abdominal Ultrasonography ◽  
Alcoholic Fatty Liver ◽  
The Past ◽  
Significant Difference ◽  
Alcoholic Fatty Liver Disease

Abstract Background In this study, to clarify the evolving background of people with non-alcoholic fatty liver disease (NAFLD), we compared the current prevalence of NAFLD with that of 2 decades ago. Methods We included two cohorts. The past cohort was from 1994 to 1997 and included 4279 men and 2502 women. The current cohort was from 2014 to 2017 and included 8918 men and 7361 women. NAFLD was diagnosed by abdominal ultrasonography. Results The prevalence of NAFLD increased in both genders throughout these 2 decades (18.5% in the past cohort and 27.1% in the current cohort for men; and 8.0% in the past cohort and 9.4% in the current cohort for women). The prevalence of hyperglycemia increased, whereas the prevalence of low high-density lipoprotein cholesterol levels and hypertriglyceridemia significantly decreased. There was no significant difference in the mean body mass index. Multivariate analysis revealed that the prevalence of obesity and body mass index were significantly associated with the prevalence of NAFLD in both the past and current cohorts. Conclusions The incidence of NAFLD significantly increased throughout these 2 decades, and obesity is the most prevalent factor. Thus, body weight management is an essential treatment option for NAFLD.

Comparative morphology of two sympatric Pareledone species from South Georgia

1994 ◽  
Vol 6 (2) ◽  
pp. 163-169 ◽  
Author(s):  
Heather I. Daly ◽  
Paul G. Rodhouse
Keyword(s):  
Reproductive Isolation ◽  
Body Mass ◽  
Comparative Morphology ◽  
Sympatric Species ◽  
Morphometric Data ◽  
South Georgia ◽  
Buccal Mass ◽  
Significant Difference ◽  
Sharp Point ◽  
Trophic Niches

Morphometric data were collected for 410 specimens of Pareledone turqueti and P. polymorpha caught around South Georgia. The two species differ in beak morphology and in the male hectocotylus. The species have similar appearances although there is a small but significant difference in the mantle length/body mass relationship for females, with P. polymorpha having a relatively longer mantle. There is no significant difference in the arm length/body mass relationship between species or sexes (p>0.05), except in the case of arm IV of females. There is an interspecific significant difference between sucker number on arms I and II of males, arms I–IV of females, and between hood length and mass of the buccal mass (p<0.05), with P. turqueti having relatively lower sucker numbers, a longer hood length and greater buccal mass mass. The beak of P. turqueti is similar to that of Eledone spp. but P. polymorpha has a small, fine beak with the rostral tip ending in an elongated, sharp point. Differences in beak and buccal mass suggest that these sympatric species occupy distinct trophic niches and that the differing morphology of the male hectocotylus is a factor in reproductive isolation.

The role of the platelet profile in the prediction of gestational diabetes

2021 ◽  
pp. 50-54
Keyword(s):  
Body Mass Index ◽  
Blood Glucose ◽  
Gestational Diabetes ◽  
Pregnant Women ◽  
Body Mass ◽  
First Trimester ◽  
Oral Glucose ◽  
Mean Corpuscular Hemoglobin ◽  
Lymphocyte Ratio ◽  
Significant Difference

Objective: In our study, the results of oral glucose tolerance test (OGTT) and other hemogram parameters of pregnant women with and without gestational diabetes mellitus (GDM) were compared. The aim of our study is to investigate the benefit of these parameters in predicting GDM risk. Material and Method: The study was planned as a descriptive, retrospective and cross-sectional study. It was included 218 pregnant women who applied to the Gynecology and Obstetrics Clinic of Amasya Sabuncuoğlu Şerefeddin Training and Research Hospital between January 01, 2019 and January 31, 2020. It was examined complete blood count parameters, ultrasound findings, complete urinalysis, first trimester blood glucose, body mass index, age, and gravide parameters the patients we included in the study. The results were analyzed retrospectively and was evaluated the statistical significance relationship with gestational diabetes. Results: There was no statistically significant difference in age, body mass index (BMI), obesity status and number of gravida between the pregnant women who were examined and those without GDM (p> 0.05). The hemoglobin, platelet count, mean platelet volume (MPV), mean corpuscular volume (MCV), mean corpuscular hemoglobine (MCH), and mean corpuscular hemoglobin concentration (MCHC) values, and neutrophil, lymphocyte, monocyte and basophil counts, urine density and femur length were statistically significant. There was no difference (p> 0.05). No statistically significant difference was found in terms of neutrophile lymphocyte ratio (NLR), neutrophile monocyte ratio (NMR), platelet lymphocyte ratio (PLR), monocyte eosinophil ratio (MER), platelet MPV ratio (PMPVR), and platelet neutrophile ratio (PNR) values (p> 0.05) Conclusion: HbA1c, hematocrit and blood glucose in the first trimester may be predictors of GDM. In addition, we think that further studies are needed in a prospective design in more patients in terms of others parameters.

The functional allometry of semicircular canals, fins, and body dimensions in the juvenile centrarchid fish, Lepomis gibbosus (L.)

Development ◽  
1973 ◽  
Vol 29 (3) ◽  
pp. 721-743
Author(s):  
Howard C. Howland ◽  
Joseph Masci
Keyword(s):  
Body Mass ◽  
Semicircular Canal ◽  
Semicircular Canals ◽  
Lepomis Gibbosus ◽  
Swimming Velocity ◽  
Body Dimensions ◽  
Moments Of Inertia ◽  
Significant Difference ◽  
Vertical Semicircular Canal ◽  
Vertical Semicircular Canals

1. The ontogenetic allometry of radii of curvature and the tube radii of the semicircular canals of approximately 85 juvenile (2–20 g) centrarchids of the species Lepomis gibbosus (L.) was investigated. The radii of curvature of the semicircular canals have different allometries; these arefor the anterior vertical, posterior vertical and horizontal canals respectively. The differences in growth exponents between the anterior and posterior vertical semicircular canals and between the anterior vertical and horizontal semicircular canals were statistically significant (P &lt; 0·02 and P &lt; 0·05 respectively). 2. Body mass and standard length were almost equally good predictors of the radii of curvature of the anterior vertical semicircular canals, but body mass was the better predictor of the radii of curvature of the posterior vertical and horizontal semicircular canals, as judged by the magnitude of the mean squares about the logarithmic regressions of radii on length and mass. 3. By measuring and estimating the area moments of the fins of the fish, the moments of inertia about various axes and the allometry of the characteristic swimming velocity of the fish, we attempted to account for the magnitude and direction of the differences in allometric growth exponents of the radii of curvature of the semicircular canals. Unexplained by our best estimate of growth exponents was the very high value observed for the posterior vertical semicircular canals. 4. No significant correlation could be found between the residuals of the major dimensions of the posterior vertical semicircular canals and those of body width or depth once the influence of body mass was removed. This finding suggests the rejection of the hypothesis that the allometry of this semicircular canal is simply correlated with overall body expansion in its plane. 5. The discrepancies between our predictions and observations of growth exponents could be explained by a gradual increase of the spring constant of the semicircular canals on the order ofthough they may also be due to other factors neglected in our model, e.g. the allometry of the added mass of the fish. 6. No evidence suggested that the shape of the semicircular canals was altered over the size range of the fish we studied. However, among the fins of the fish and the major body dimensions, only the width and the depth of the fish exhibited growth constants that did not differ significantly from each other. 7. We computed the effective toroidal radii of the non-toroidal-shaped vertical semicircular canals and found that the equivalent toroidal radius of the anterior vertical semicircular canal was consistently greater than that of the posterior vertical semicircular canal. This difference is explicable on the basis of the different moments of inertia of the animal about axes through the center of gravity and parallel to the axes of the semicircular canals. 8. We computed the allometry of the ratios R̄/r2 for all three semicircular canals and found in accordance with the prediction of Jones & Spells that they did not differ significantly from zero. 9. The allometry of the outer tube radii of the several semicircular canals was determined, and, while there was no significant difference in the growth exponents of the tube radii, it was noted that the tube radius of the horizontal semicircular canal was consistently and significantly smaller than that of the vertical semicircular canal. We suggested that this difference might be due to the broader range of frequencies that the fish experienced about its yaw axis. 10. Taken as a whole the data and calculations of this paper generally support the theory that the dimensions of the semicircular canals and the ontogenetic changes in them attune the semicircular canals to the angular frequency spectra that the fish experience about their axes.

Interruption of cardiac output does not affect short-term growth and metabolic rate in day 3 and 4 chick embryos

2000 ◽  
Vol 203 (24) ◽  
pp. 3831-3838 ◽  
Author(s):  
W.W. Burggren ◽  
S.J. Warburton ◽  
M.D. Slivkoff
Keyword(s):  
Blood Flow ◽  
Cardiac Output ◽  
Body Mass ◽  
Regression Line ◽  
Heart Beat ◽  
Chick Embryos ◽  
Simple Diffusion ◽  
Significant Difference ◽  
Vertebrate Embryos ◽  
Cervical Flexure

The heart beat of vertebrate embryos has been assumed to begin when convective bulk transport by blood takes over from transport by simple diffusion. To test this hypothesis, we measured eye growth, cervical flexure and rates of oxygen consumption (V(O2)) in day 3–4 chick embryos denied cardiac output by ligation of the outflow tract and compared them with those of embryos with an intact cardiovascular system.Eye diameter, used as the index for embryonic growth, increased at a rate of approximately 4.5-5 % h(−)(1) during the observation period. There was no significant difference (P&gt;0.1) in the rate of increase in eye diameter between control (egg opened), sham-ligated (ligature present but not tied) and ligated embryos. Similarly, the normal progression of cervical flexure was not significantly altered by ligation (P&gt;0.1). V(O2) (ml O(2)g(−)(1)h(−)(1)) at 38 degrees C, measured by closed respirometry, was not significantly different (P&gt;0.1) on day 3 in sham-ligated (14.5+/−1.9 ml O(2)g(−)(1)h(−)(1)) and ligated 17.6+/−1.8 ml O(2)g(−)(1)h(−)(1)) embryos. Similarly, on day 4, V(O2) in sham-ligated and ligated embryos was statistically the same (sham-ligated 10. 5+/−2.9 ml O(2)g(−)(1)h(−)(1); ligated 9.7+/−2.9 ml O(2)g(−)(1)h(−)(1)). Expressed as a linear function of body mass (M), V(O2) in sham-ligated embryos was described by the equation V(O2)=−0.48M+24.06 (r(2)=0.36, N=18, P&lt;0.01), while V(O2) in ligated embryos was described by the equation V(O2)=−0.53M+23.32 (r(2)=0.38, N=16, P&lt;0.01). The regression line describing the relationship between body mass and V(O2) for pooled sham-ligated and ligated embryos (the two populations being statistically identical) was V(O2)=−0.47M+23.24. The slope of this regression line, which was significantly different from zero (r(2)=0.30, N=34, P&lt;0.01), was similar to slopes calculated from previous studies over the same range of body mass.Collectively, these data indicate that growth and V(O2) are not dependent upon cardiac output and the convective blood flow it generates. Thus, early chick embryos join those of the zebrafish, clawed frog and axolotl in developing a heart beat and blood flow hours or days before required for convective oxygen and nutrient transport. We speculate that angiogenesis is the most likely role for the early development of a heart beat in vertebrate embryos.

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