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1.
1. Three experiments were conducted with broiler chickens using hypobaric chambers and control pens, feeding diets containing 25 or 50 g flax oil/kg food or control diets with equivalent amounts of animal/vegetable (A/V) blend oil for 4 weeks. The effect of these diets on haematological variables and the extent of right ventricular hypertrophy (RVH) leading to ascites was determined. 2. Overall growth rate was not consistently affected by dietary treatment, although feeding the 25 g flax oil/kg diet reduced weight gain in week 4 of one experiment. Feeding the 50 g flax oil/kg diet but not the 25 g flax oil/kg diet reduced RVH in birds exposed to hypobaric conditions compared to feeding control diets. 3. Feeding the 50 g flax oil/kg diet under hypobaric conditions reduced the haematocrit and haemoglobin content, increased the erythrocyte deformability and the proportion of unsaturated fatty acids in the erythrocyte membranes, and reduced the whole blood viscosity compared to feeding control diets. These effects were not seen when the 25 g flax oil/kg diet was fed. The ratio of n-3 to n-6 fatty acids in erythrocyte membranes was increased in the 50 g flax oil/kg treatment group compared to controls. 4. Including 50 g flax oil/kg broiler diet reduces RVH in broiler chickens. This may be attributable in part to an increase in erythrocyte deformability from an increased proportion of unsaturated fatty acids in the erythrocyte membranes.  相似文献   

2.
Echocardiography was used to study cardiovascular structure and function during the development of pulmonary hypertension syndrome (PHS) in broiler chickens. Body weight-normalized right and left ventricular diameters at both end-diastole (RVDD, LVDD) and end-systole (RVDS, LVDS) were determined weekly in broilers reared under either normobaric (altitude, 96.7 m) or hypobaric conditions (simulated altitude, 2900 m) until 5 wk of age. Hypobaric-exposed broilers had larger RVDD at 3 and 4 wk of age and larger RVDS at 3, 4, and 5 wk of age. Hypobaric-exposed broilers also had larger LVDD at 2, 3, 4, and 5 wk of age and larger LVDS at 4 wk of age. Right (RVFS) and left ventricular fractional shortening (LVFS) were smaller in hypobaric- vs. normobaric-exposed broilers at 3, 4, and 5 wk of age and at 4 wk of age, respectively. Among hypobaric-exposed birds, PHS-positive (+) broilers had larger RVDD and RVDS than PHS-negative (-) broilers on week 3 and on weeks 1 and 3 after hypobaric exposure, respectively. PHS-positive (+) broilers also had smaller RVFS on week 1 after hypobaric exposure. Electrocardiographic and post-mortem data indicated that PHS+ broilers also developed right ventricular hypertrophy when compared with PHS-negative (-) broilers. These results are consistent with the hypothesis that PHS develops as a result of pulmonary hypertension and cardiac overload and suggest that PHS+ broilers have a greater and more persistent reaction to hypoxia than PHS- broilers.  相似文献   

3.
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4.
1. There are few studies on the effect of dietary protein content on pulmonary hypertension syndrome (PHS) in broiler chickens. Conflicting results from these studies prevent a clear conclusion on the effects of reduced-protein diets on development of the syndrome.

2. To obtain an understanding of the mechanisms involved, the current study, conducted at a high altitude (2100?m above sea level), evaluated the effect of three treatments that varied only according to dietary protein (CP) levels. One treatment with dietary CP advocated by National Research Council (1994) acted as a control. Two reduced-protein diets were also prepared with CP reduced 20 and 40?g/kg relative to the CP of the control, which were designated as LCPD2 and LCPD4, respectively. A total of 180?d-old male broilers (Ross 308) were randomised across 15 floor pens measuring 1.5?m2 (12 birds per pen). Five such pens (replicates) were allotted to each dietary treatment. The protein treatments were applied from 1 to 42?d of age in which growth performance was measured and the mortality from PHS was monitored. At the end of trial (42?d), blood sampling was done and carcase characteristics were recorded.

3. Birds receiving LCPD4 gained more weight throughout the trial and had increased right ventricular weight ratio (RV:TV), relative liver weight, haematocrit, and heterophil: lymphocyte ratio at the end of the trial compared to the control. Plasma concentrations of nitric oxide (NO) and uric acid, however, were significantly lower in birds fed on LCPD4 than in those receiving the control diet.

4. Mortality from PHS was increased in birds fed the reduced-protein diets, which may have been associated with reduced concentration of plasma NO and increased haematocrit and RV:TV. In conclusion, feeding reduced-protein diets to broilers subjected to hypobaric hypoxia was associated with the development of PHS.  相似文献   

5.
Phonocardiography was evaluated as a noninvasive technique for diagnosis of cardiovascular adaptation and disease in broiler chickens. Heart sounds (HSs) were compared in a fast-growing (FG) commercial broiler line that is highly susceptible to chronic right heart failure resulting from pulmonary hypertension syndrome (PHS) and in a non-selected slow-growing (SG) broiler line that is resistant to PHS. HSs were analyzed in broilers reared in hypobaric hypoxia (HYP) and normobaric (CON) conditions. PHS was induced by a combination of embryonic hypoxia and HYP exposure. HSs were recorded with a microphone placed at the thoracic inlet of each chicken. Electrocardiograms were used to mark the sampling interval for the first, second, and total HS. Digitized HS signals were analyzed for peak frequency, mean peak frequency, and band width. Birds were examined for PHS lesions when 6 wk of age, at the end of each experiment. HSs were compared by line and treatment (Experiment 1) or by treatment and week (Experiment 2). In addition, HS frequencies were analyzed within the HYP treatment group for differences between birds with severe or no gross PHS lesions. HS frequencies generally decreased with age and were also lower in the FG than the SG line. Hypobaric exposure decreased all HS frequencies in the SG line and components of the first HSs in the FG line. The SG line did not develop gross lesions of PHS. In the FG line, significant differences in HS frequencies were observed between HYP and CON groups but not between PHS- and PHS+ broilers. Frequency changes described in humans with PHS were not observed. Further development to maximize the resolution of the HS waveforms and improved matching of the sampling interval to the electrical or hemodynamic output of the chicken heart may allow its use as a diagnostic tool for differentiating broilers with normal cardiac function or physiologic adaptation from those with cardiovascular disease.  相似文献   

6.
Pulmonary hypertension syndrome (PHS), also known as ascites, in broiler chickens prevailed in the local area of Ibaraki prefecture, Japan, and was investigated epidemiologically, serologically, and pathologically. PHS developed in chickens older than 35 days of age when rapid increase of body weight started. Approximately 90% of affected birds were males, in which weight increase was greater than in females. Serologic test revealed that PHS broilers had an increase of hematocrit value. Pathologic studies indicated that the heart of affected birds had an obese-induced pressure and cold exposure triggered congestion in the right ventricle/cava and an increase in peritoneal fluid. These changes were consistent with the previous reports of PHS, so we designed the experiment of effects on cold-induced PHS birds in a temperature-controlled house. After the 10 PHS birds at 55 days were reared for 14 days in a temperature-controlled house at 20 +/- 5 C, ascites disappeared in eight birds and hematocrit values decreased to normal range in nine birds. Our finding indicated that temperature-controlled environment may be one solution to reduce mortality in PHS birds.  相似文献   

7.
Two groups of young broiler chickens, namely, naturally occurring field cases of ascites and those with an induced hypoxia, were used in an ultrastructural study to examine the localisation and distribution of intracellular Ca2+ in cardiomyocytes. Age-matched healthy flockmates were used to control each group. Deposits of Ca2+ were located extensively in the mitochondria, sarcoplasmic reticulum and Golgi apparatus and sometimes in the myocyte and endothelial cell nuclei of both groups of birds. The results suggest that the cells from the hearts of the ascitic broilers may have been exposed to hypoxia since a large proportion of control material showed no Ca2+ activity in either mitochondria or nuclei. The presence of a Ca2+ overload in the mitochondria of cardiomyocytes from ascitic birds reared at low altitude or sea level suggests that these broilers were suffering from the deleterious effects of chronic hypoxia due to poor or reduced oxygen use.  相似文献   

8.
1. This experiment investigated the effects of water and Saccharomyces cerevisiae added to wheat-based diets on gastrointestinal, blood and performance parameters of broiler chickens. 2. A total of 160 one-d-old male broiler chicks were given air-dry or wet diets, with or without S. cerevisiae supplementation (0 and 20 g/kg air-dry feed) ad libitum to 42 d. 3. Feeding broilers with a diet mixed with water in a ratio of 1·2 : 1·0 increased body weight, feed intake, abdominal fat, carcase weight, feed transit time and blood HDL (high density lipoprotein) (without yeast). Supplementation with S. cerevisiae increased DM digestibility but reduced ileal pH, ileal coliform population and abdominal fat content. 4. There was a significant interaction between S. cerevisiae and wet feeding, with S. cerevisiae supplementation inducing a significant increase in body weight and feed intake but a reduction of relative abdominal fat and ileal pH of broilers fed on wet diets. 5. It is concluded that wet feeding improved growth performance by increasing feed intake and that the addition of a culture of S. cerevisiae had a growth stimulating effect, as the inclusion of yeast in wet wheat-based broiler diets generated greater responses than yeast in dry-based diets.  相似文献   

9.
Research has shown that broiler chickens reared on a low-protein diet have a more efficient protein digestion. However, information on the fate of absorbed amino acids in relation to the dietary crude protein level in poultry is sparse. Therefore, this study aimed at developing a methodology for a 1-(13)C(1)-leucine breath test combined with indirect calorimetry, and to apply this technique using broiler diets known to induce differences in protein retention. From 14 days of age onwards, broiler chickens were reared on one of two isocaloric diets with substitutions between fat and protein [low-protein (LP) vs. high-protein (HP) diet: 130.4 vs. 269 g protein/kg; and 101.8 vs. 27.9 g fat/kg]. Every 4 or 5 days, three chickens per diet were placed in the respiratory cells for 48 h. The broilers were intubated with 40 mg 1-(13)C(1)-leucine/kg body weight, followed by breath sampling for 4 h at 15-min intervals and mass spectrometric analysis of the (13)C:(12)C ratio in the samples. The CO(2) level in the respiratory cell air was monitored and excreta samples were collected. The methodology to study l[1-(13)C(1)]leucine decarboxyation in chickens using a breath test combined with indirect calorimetry was accomplished. Results of the nitrogen balance test indicated that the LP broilers had an improved dietary protein retention compared with the HP animals. Moreover, LP chickens decarboxylated a significantly lower percentage of l[1-(13)C(1)]leucine, demonstrating several 'protein- or amino acid-sparing' mechanisms in animals reared on a diet with lower protein level, both at the digestive and at the postabsorptive level.  相似文献   

10.
Oxidative stress is involved in the development of pulmonary hypertension syndrome (PHS) in broilers. l-Carnitine has an antiperoxidative effect and supplemental l-carnitine has been revealed to increase broiler heart weight. The present study was conducted to evaluate the effect of an addition of 100 mg/kg l-carnitine to the basal diets on PHS mortality in cold-exposed broilers. Two-hundred and forty mixed-sex broilers were equally assigned to three groups. The control group was reared in normal temperatures throughout the experiment. Starting on day 14 continuing until the end of the experiment, the other two groups were subjected to a step-down temperature programme (by lowering the temperature 1-2 degrees C per day down to 12-14 degrees C) with or without l-carnitine added to the basal diets. Cold exposure increased the right/total ventricle ratio (RV/TV) and plasma malondialdehyde (MDA), reduced superoxide dismutase (SOD) and led to pulmonary vascular remodelling in birds without feeding additional l-carnitine. Supplemental l-carnitine reduced plasma MDA, increased SOD, inhibited remodelling and postponed the occurrence of PHS for 1 week in cold-exposed broilers; nevertheless, it did not significantly influence the cumulative PHS mortality (p > 0.05). On days 24 and 32, birds fed supplemental l-carnitine had lower RV/TV and higher total ventricle/body weight (p < 0.05) but unchanged right ventricle/body weight ratios (p > 0.05) compared to their cold-exposed counterparts, indicating an increase in left ventricle weight. However, from day 39 on, their RV/TV ratios were suddenly increased (p < 0.05). It was suggested that the l-carnitine-induced increase in left heart weight might partially account for the postponed occurrence of pulmonary hypertension in the early stage by elevating cardiac output, which might, in turn, lead to the resulting increase in pulmonary pressure. In view of its complex effects on cardiopulmonary haemodynamics, l-carnitine supplementation may be impractical for reducing PHS.  相似文献   

11.
1. Three experiments were conducted using a low temperature model to induce pulmonary hypertension (PH) and ascites in broiler chickens. Diets containing 25 g or 50 g flax oil/kg food and control diets with an equivalent amount of animal/vegetable (A/V) blend oil, with and without supplemental antioxidants (vitamin C and vitamin E) were used. The amount of PH was assessed by the ratio of right ventricle weight to total ventricle weight (RV/TV ratio). Birds were considered to suffer from pulmonary hypertension syndrome (PHS) if the RV/TV ratio was greater than 0.299. 2. In experiment 1, the test diets contained 50 g oil/kg food and were given during the grower period only. Birds fed on the flax oil diet tended to have a lower incidence of PHS, ascites and lower RV/TV ratios than birds fed on the control diet. However, when the flax oil diet was supplemented with antioxidants, the incidence of ascites, PHS, haematocrit and whole blood and plasma viscosity increased compared with birds fed on the flax oil diet without antioxidants. These effects were not seen in experiment 2, when the test diets containing 30 g oil/kg food (25 g flax oil plus 5 g A/V blend oil/kg food compared to 30 g A/V blend oil/kg food) were given during the grower period. However, in experiment 3, when the test diets containing 30 g oil/kg food were given from day 1 to week 8, birds fed on the control diet supplemented with antioxidants had a higher incidence of PHS than those fed on the control diet alone. 3. In all 3 experiments, there was no significant effect of dietary fat source or supplemental antioxidants on total food intake or food conversion. 4. We conclude that diets containing 50 g flax oil/kg food tend to reduce the incidence of PHS and ascites in broilers using a low temperature model but the results were not statistically significant. In some cases, supplementing diets with a combination of vitamin E and vitamin C increased the incidence of ascites and PHS.  相似文献   

12.
试验旨在研究红景天提取物对高原缺氧条件下肉鸡接种法氏囊疫苗和绵羊红细胞后产生的特异性抗体水平的影响。随机选取100只1日龄健康AA肉仔鸡,随机分为5组。其中,对照组只饲喂基础日粮,其余4组分别在基础日粮中添加0.10%、0.15%、0.20%和0.40%红景天水提物干粉。每个组取半数鸡只于13日龄腹腔注射接种绵羊红细胞,另一半鸡只于20日龄口服接种法氏囊疫苗。研究发现,免疫接种法氏囊疫苗后2 d和19 d,相比于对照组,0.20%和0.40%红景天处理组显著提高了法氏囊疫苗抗体水平(P<0.05)。在腹腔注射绵羊红细胞后5 d、8 d和12 d时,相比对照组,0.20%和0.40%红景天处理组显著提高了绵羊红细胞抗体水平(P<0.05)。该试验表明红景天提取物可以提高高海拔缺氧条件下肉鸡特异性抗体水平,因此其可能作为高海拔缺氧条件下肉鸡日粮的一种免疫调节性添加剂。  相似文献   

13.
The objective of this study was to examine the effectiveness of early-age growth limitation, achieved through feed restriction (FR), as a means of reducing ascites mortality in broiler chickens exposed to low ambient temperatures. Feed restriction was applied to broilers from 5 to 11 d of age so as to reduce their weight gain to about 40% of that of control broilers that were fed ad libitum (AL). At the age of 21 d the chickens were exposed to a temperature of 15°C, which induced ascites. By 46 d of age, ascites incidence and mortality in the feed-restricted birds were reduced to 15.79 vs. 36.84% and 7.89 vs. 26.32%, respectively, compared with those in the controls (P < 0.05). After feed restriction was stopped, the FR chickens had accelerated weight gain and improved feed conversion ratio from 11 to 18 d of age (P < 0.05), and by 46 d they had achieved the same body weight as the AL birds. Ascitic broilers had smaller relative breast muscle and spleen weights than those of the healthy broilers at 46 d (P < 0.05). However, the relative weights of lung, heart, and liver and the right ventricle weight per total ventricle weight (RV:TV) ratios were greater in ascitic broilers (P < 0.05). At age 37 d, when ascites had developed but not yet caused mortality, the ascitic broilers had lower plasma concentrations of the thyroid hormones thyroxine and triiodothyronine, and higher hematocrit values (P < 0.05) in comparison with the healthy ones. Ascitic birds also had lower oxygen consumption at 6 wk (P < 0.05), which agrees with information that the terminal stage of the ascites syndrome can be characterized by low oxygen consumption. We concluded that the early-age feed restriction reduced ascites incidence and mortality and prevented reduction of the thyroid hormone concentrations in male broilers reared at low ambient temperature from the age of 3 wk onward.  相似文献   

14.
Phosphorus-deficient diets fed to broiler chicks from day 1 to day 21 induced rickets. Some chicks were stunted, but most grew well, though they had increased respiratory rates, high arterial carbon dioxide partial pressure, and low oxygen partial pressure and were polycythemic. Most of the broilers that died showed signs of pulmocardiovascular abnormalities, some died from hypoxia, and some died from right ventricular failure with or without ascites. Many broilers had mild to marked right ventricular hypertrophy and dilation with or without ascites when examined at 21 days. It is suggested that right ventricular hypertrophy and dilation was a response to pulmonary arterial hypertension caused by chronic hypoxia, which resulted from inability to breathe normally because of poor rib strength and infolding. When right ventricular failure occurred, it was secondary to right ventricular hypertrophy and dilation.  相似文献   

15.
1. Five diets containing different amounts of protein (178, 210, 243, 275, 308 g/kg) were fed to broilers reared at 16, 21, 26 and 31 °G from 27, 21, 11 and 1 d of age, respectively.

2. Feeding the diets with increased concentrations of protein apparently does not reduce the growth rate depression of the broiler reared at 26 or 31 °C.  相似文献   


16.
A reduced‐protein diet (designated as RPD) was prepared and its effects on growth performance and the development of pulmonary hypertension syndrome (PHS) were evaluated in broiler chickens compared to a normal‐protein diet (designated as NPD) or to the RPD supplemented with CoQ10 alone (30 mg/kg) or in combination with vitamin E (30 mg/kg CoQ10 + 100 mg/kg vitamin E). The RPD had 30 g/kg less crude protein compared to the NPD. A total of 208 1‐day‐old male broilers (Ross 308 strain) were used in a 42‐day trial. Serum concentrations of uric acid (UA) and nitric oxide (NO) significantly (p < 0.05) declined when chickens fed on the RPD. However, supplementing RPD with the antioxidants significantly (p < 0.05) increased the serum NO concentration. Although serum malondialdehyde (MDA) concentration was significantly (p < 0.05) higher in the RPD than the NDP, supplementing RPD with CoQ10 and CoQ10 + VE decreased serum MDA concentration to similar levels found in the NPD. Significant overexpression in GPX1 gene observed in the heart and lungs of broilers fed on the RPD, which was effectively restored by supplementation of CoQ10. The right to total ventricular weight ratio (RV:TV) was significantly (p < 0.05) increased in birds fed the RPD, which concurred with an increase in mortality from pulmonary hypertension syndrome (PHS). However, a significant decline in mortality from PHS was observed when birds on RPD received CoQ10 or CoQ10 + VE. In conclusion, antioxidant supplementation effectively improves pulmonary hypertensive response in broiler chicken fed of reduced‐protein diets.  相似文献   

17.
试验比较了轻(蛋)、重(肉)型鸡0～10周的生长发育、体成分和营养物质利用率,同时观察了饲粮能量水平对二类型鸡的影响效应。白来航和白洛克公鸡喂以相同蛋白质水平(19％)而不同能量浓度的三个饲粮(能量浓度分别为2.72,2.95和3.16千卡/克)。 采食同样饲粮的情况下,肉鸡具有较快的生长速度(肉鸡体重在10周末是蛋鸡的2.37倍,采食量是1.76倍)和较高的体脂肪(％)(P<0.01)。饲料效率、能量效率和蛋白质利用效率(％)均非常显著地高于蛋鸡(P<0.01),而体蛋白(％)低于蛋鸡(P<0.01)。认为肉鸡生长较快不仅与采食量有关,较高的饲料、能量和蛋白质利用率也是促进快速生长的重要因素。 在三个供饲能量水平下,肉鸡受能量浓度的影响较明显,尤其是高能水平的饲粮。低能水平的饲粮仅对蛋鸡采食量(P<0.05)和肉鸡体蛋白(P<0.01)有作用。较高的饲粮能量水平不仅使肉鸡生长速度加快,体脂肪增高,而且明显改进饲粮能量和蛋白质利用效率(P<0.01)。  相似文献   

18.
1. The effects of varying the dietary arginine:lysine (Arg:Lys) ratio for broiler chickens at thermoneutral and high temperatures was studied in a series of 5 experiments which measured intestinal epithelial transport or evaluated growth and food efficiency with practical diets or diets supplemented with L-arginine free base. 2. The growth studies showed that increasing the Arg:Lys ratio at high temperatures produced consistent improvements in food conversion without any loss in growth. 3. Increasing dietary sodium chloride concentration reduced the Arg:Lys ratio necessary for optimum food conversion. 4. Food conversion responses were improved whether L-arginine free base was used as a dietary supplement in place of an inert filler or practical diets with differing ingredients were used to vary the Arg:Lys ratio. 5. In the presence of an equimolar concentration of lysine the uptake of arginine by the intestinal epithelium of heat-stressed broilers was reduced significantly compared with that of broilers at thermoneutral temperatures. 6. The results indicate that the ideal amino acid balance for broilers varies with ambient temperature.  相似文献   

19.
Vectorelectrocardiographic (VCG) analysis was performed on 50 male broiler chicks (1 week of age) before placement in a hypobaric chamber. During 5 weeks of exposure to hypobaric hypoxia (simulated altitude of 2900 m), all recorded mortality (38%) was due to the development of ascites syndrome. There was a positive correlation (r = 0.74, P less than 0.01) between the increment in the frontal plane mean resultant vector magnitude divided by body weight (designated as the cardiac index [CI]), with the severity of right ventricular enlargement. Chicks developing ascites syndrome had a greater CI (P less than 0.05) at 1 week of age when compared with chicks that did not develop the syndrome. Therefore, the CI calculated by VCG analysis recognizes right ventricular enlargement, suggesting that a pre-hatch or early post-hatch functional cardiac stress has occurred, predisposing the 1-week-old broiler chick to ascites syndrome. Application of the CI has a physiological index may prove useful in future studies targeted for selection of ascites syndrome resistance in broiler chickens.  相似文献   

20.
Krill meal was used as a protein feed in rations for broiler chickens and laying hens and its nutritional effectiveness was studied in comparison with conventional feed-stuffs of animal origin. In experiments with 650 broiler chickens from 1 to 28 and from 29 to 56 days to fattening krill meal was added to the standard feedmixture in lieu of fish meal, and dried skim-milk, and at higher levels also in lieu of soyabean oilmeal. In the experiment with 22 layer hens kept in individual cages 3% of the fish meal were substituted by 3% of krill meal. The performance of chickens fed on diets with krill meal was lower in comparison with analogical groups fed on fish meal. Higher levels of krill meal, exceeding 15 and 11% in the first and second period of feeding respectively, reduced the weight gains and feed intake of chickens. The fatty acid C14, C18 and C18:1 content of internal body fat was changed in chickens fed on higher levels of krill meal. In the experiment with hens krill meal decreased the feed efficiency, the pigmentation of egg yolks, however, was more intensive and the vitamin A content of yolks was increased in comparison with the control group. The results show that krill meal can be used as a partial substitute of fish meal in the feed of broilers and hens.  相似文献   

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