Comparison of serum biochemical profiles of male broilers with female broilers and White Leghorn chickens.

Male broiler chickens were compared to female broiler chickens and male White Leghorns with respect to a 15-parameter serum biochemical profile at 9, 20, 30 and 42 days of age in order to determine which, if any, of the parameters tested might be useful in the identification of birds susceptible to sudden death syndrome. In comparison to female broilers, male broilers had significantly lower (p less than 0.01) total protein levels at 20 days of age and significantly higher (p less than 0.01) cholesterol levels at 30 days of age. Compared to male White Leghorns, in which sudden death syndrome has not been reported, male broilers had significantly lower (p less than 0.01) levels of cholesterol and creatinine at nine days of age, total protein at 9 and 20 days of age and albumin at 20 days of age and significantly higher (p less than 0.01) levels of potassium at nine days, uric acid at 9, 20 and 30 days, lactate dehydrogenase at 20, 30 and 42 days and cholesterol at 30 days of age.     

Effects of Early Feed Restriction on Performance and Ascites Development in Broiler Chickens Subsequently Raised at Low Ambient Temperature

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.     

早期限饲对肉鸡补偿性生长的影响

试验观察了几种早期限饲措施对肉鸡补偿性生长和消化器官发育的影响。结果显示,各种早期限饲处理均可明显降低肉鸡早期的生长速度和体重;恢复自由采食后肉鸡获得了补偿性生长,适当的早期限饲并不影响肉鸡的最终上市体重;早期限饲改善了饲料效率;限饲鸡胰脏相对重量和肌胃 腺胃相对重量显著高于非限饲鸡,提示早期限饲诱发肉鸡补偿性生长可能与限饲促进消化器官发育、提高消化能力有关。     

AA肉鸡和北京油鸡早期消化器官发育规律研究

本试验旨在比较AA肉鸡和北京油鸡在胃肠道消化生理上的差异。选择1日龄雄性AA肉鸡和北京油鸡各50只,每个品种为1个处理,2个处理的日粮和饲养管理一致,每个处理5个重复,每个重复10只鸡。试验期28 d。在0、7、14、21、28日龄,每个品种分别选择10只鸡屠宰,测定其体重、肝脏、胰腺、腺胃、肌胃、小肠及小肠各段的重量,并且测定小肠及小肠各段的长度。结果表明:AA肉鸡和北京油鸡的体重均随着日龄增加而增加,相同日龄下AA肉鸡的体重高于北京油鸡(P<0.01);AA肉鸡和北京油鸡消化器官的发育规律类似,腺胃、肝脏、胰腺、小肠及小肠各段的相对重量均在7日龄达到最大值,肌胃相对重量、小肠和小肠各段的相对长度以及消化器官异速生长值均随着日龄增加而逐渐降低;7~28日龄,北京油鸡小肠和小肠各段的相对长度以及小肠各段长度异速生长值高于AA肉鸡(P<0.05),北京油鸡小肠及小肠各段的肠道密度低于AA肉鸡(P<0.05),AA肉鸡消化器官(肝脏、胰腺、腺胃和肌胃)绝对重量均高于北京油鸡(P<0.01),AA肉鸡腺胃、肌胃和肝脏的相对重量低于北京油鸡。综上所述,AA肉鸡的生长速度高于北京油鸡,而绝大多数消化器官相对重量低于北京油鸡;孵化后1周是肉鸡消化器官发育的关键时期,消化器官的增重速度高于体重增加速度,消化器官发育是体重快速增长的前提条件。     

Responses to heat stress in commercial and local broiler stocks. 2. Developmental stability of bilateral traits.

1. Developmental stability of bilaterally symmetrical traits was measured in two fast (G1 and G2) and one slower growing (G3) broiler stocks when conditioned (chicks exposed to 36 degrees C for 24 h at 5 d of age) or food restricted (food withdrawn 2 h before the hot period and chicks fed between 17.00 and 08.00 h) during heat stress administered daily from 28 to 49 d of age. 2. Length of face, length, width and weight of shanks, weights of P. major and P. minor muscles, and weights of lung and caeca were chosen as bilateral traits representative of skeletal, muscle, respiratory and digestive systems. 3. Development of skeletal bilateral traits was affected primarily by genotype and sex. The heart:lung ratio decreased with conditioning in stocks G1 and G2 at 21 d. Face length, shank length and shank weight exhibited antisymmetry, whereas shank width and weights of P. minor, lung and caeca exhibited fluctuating asymmetry and antisymmetry. For P. major weight, there was directional asymmetry. 4. In general, relative asymmetry of skeletal traits was lower than for traits associated with muscle and with respiratory and digestive systems. Relative asymmetry of P. major weight was lower in conditioned and G3 broilers than in their respective counterparts. 5. If relative asymmetry is a valid indicator, item heat stress may be less in slower growing and conditioned broilers.     

Studies on effect of lighting on "Sudden death syndrome" in broiler chickens.

Broiler chicken flocks were studied to determine the mortality from sudden death syndrome occurring in the flocks. The difference in the incidence of the syndrome in pullets and cockerels, and the age at which the most birds are affected were also studied. The weight of sudden death syndrome birds was compared with the flock average and the effect of continuous lighting as opposed to intermittent lighting was examined.The results suggest that; continuous lighting produces more sudden death syndrome deaths than intermittent lighting; that the incidence of sudden death syndrome is higher in cockerels than pullets; that the highest death rate occurred during the third and fourth weeks of life, and that sudden death syndrome birds on the average were heavier than the flock average.     

Studies on Effect of Lighting on “Sudden Death Syndrome” in Broiler Chickens

Broiler chicken flocks were studied to determine the mortality from sudden death syndrome occurring in the flocks. The difference in the incidence of the syndrome in pullets and cockerels, and the age at which the most birds are affected were also studied. The weight of sudden death syndrome birds was compared with the flock average and the effect of continuous lighting as opposed to intermittent lighting was examined.

The results suggest that; continuous lighting produces more sudden death syndrome deaths than intermittent lighting; that the incidence of sudden death syndrome is higher in cockerels than pullets; that the highest death rate occurred during the third and fourth weeks of life, and that sudden death syndrome birds on the average were heavier than the flock average.

     

Effects of divergent selection for incidence of tibial dyschondroplasia (TD) on purebred and crossbred performance. 2. Processing yield

1. An experiment was conducted to determine the effect of selection for high (H) or low (L) incidence of tibial dyschondroplasia for 7 generations on processing performance of broilers. 2. Birds were obtained from diallel matings of the H and L lines (HH, HL, LH, and LL) and a randombred control (CC) line. Birds were reared to 7 weeks of age under standard management conditions. All birds were processed at 7 weeks of age. Body weight at 7 weeks, carcase weight, and carcase part weights were recorded on each bird. 3. An interaction between sire line and dam line was caused by lighter body and carcase weight at 7 weeks of age in HH birds than from the birds of the other crosses. 4. Birds by L line dams had heavier drumstick weights. The influences of sire line and dam line on weight of total breast muscle were not significant. Thigh weights and Pectoralis minor weights were lighter in HH line birds than those other matings. 5. Heterosis for body weight and for weights of carcases, drumstick and thigh was negative. Total breast muscle weight and P. major weight did not show significant heterosis. 6. It was concluded that selecting against TD does not reduce processing yield of broilers.     

The effect of increased mineral levels in the feed on leg weakness and sudden death syndrome in broiler chickens

In two experiments with 98,000 and 40,000 broilers on commercial broiler farms, half of each flock were fed starter, grower and finisher diets with 0.2% added calcium, 0.2% added phosphorus and 0.2% added magnesium. This ration had no significant effect on the incidence of sudden death syndrome but the incidence of leg weakness in broilers on the increased mineral ration was higher in both flocks.

Approximately 28% of the mortality in both flocks was from sudden death syndrome, more than from any other condition. Approximately 20% of the mortality was associated with leg weakness.

     

Chronic effects of moniliformin in broiler and turkeys fed dietary treatments to market age

Floor pen studies were conducted, with broilers from 1 to 7 wk of age and with turkeys from 1 to 14 wk of age, to evaluate the chronic effects of moniliformin (M). Fusarium fujikuroi (M-1214) culture material was added to typical corn-soybean basal diets to supply 0, 25, or 50 mg M/kg diet (broilers) or 0, 12.5, 25, 37.5, or 50 mg M/kg diet (turkeys). Compared with controls, chicks fed diets containing 50 mg M/kg consumed more feed, had lower body weight gain, were less efficient in converting feed to body weight gain, and had increased relative heart and proventriculus weights. Chicks fed the diet containing 50 mg M/kg also had significantly higher mortality and decreased mean corpuscular volumes compared with controls. Broilers fed 25 and 50 mg M/kg also had increased serum gamma glutamyltransferase activities. Feed intake, body weight gain, and feed conversion of turkeys fed dietary M were not affected. At 6 and 14 wk, turkeys fed 25, 37.5, or 50 mg M/kg diet had increased (P < 0.05) relative heart weights when compared with controls. At week 14, turkeys fed diets containing 37.5 or 50 mg M/kg also had increased (P < 0.05) relative liver weights compared with turkeys fed 0, 12.5, or 25 mg M/kg diet. Lesions, observed only in the hearts of broilers and turkeys fed 50 mg M/kg, were loss of cardiomyocyte cross striations, increased cardiomyocyte nuclear size, and an increased number of cardiomyocyte mitotic figures (turkeys only). Results indicate that > or = 37.5 mg M/kg is hepatoxic and > or = 25 mg M/kg is cardiotoxic to turkeys and 50 mg M/kg diet is toxic to broilers fed to market age.     

Decreased thyroxine, triiodothyronine, and 5'-deiodination levels in malabsorption syndrome (runting or stunting syndrome) in artificially inoculated broilers

The effect of malabsorption syndrome (stunting or runting syndrome) on the thyroid function of broilers was investigated in control and inoculated broilers from 1 to 29 days of age. The broilers were infected at 1 day of age with intestinal homogenates from chickens naturally suffering from this syndrome. The body weight of inoculated broilers was significantly (P less than 0.05) lower 1 week after inoculation than that of controls. The level of thyroxine in the serum of inoculated birds was lower (P less than 0.05) from day 6 through the remainder of the trial. The level of triiodothyronine of inoculated birds was depressed (P less than 0.05) on day 4, but 1 week later it returned to normal. The earliest phenomenon indicative of disturbance of thyroid function was the significant depression of 5'-deiodination in liver homogenates of inoculated broilers as early as day 2. It is concluded that thyroid function is one of the earliest targets of this syndrome.     

Chicken anemia virus in broilers: dynamics of the infection in two commercial broiler flocks

Chicken anemia virus (CAV) can cause a disease syndrome characterized by severe anemia, bone marrow atrophy, and severe immunosuppression in young chicks. Maternal antibodies prevent these clinical signs but do not prevent infection, transmission of the virus, or immunosuppression. The clinical disease is rare today because of the widespread practice of vaccinating breeders, but the subclinical form of the disease is ubiquitous. The dynamics of CAV infection, CAV antibody responses, relative lymphoid organ weights, and associated lesions were studied in two broiler flocks from a commercial producer. Both groups had detectable CAV antibodies at hatch, which waned over the first 3 wk of life. Both groups had detectable CAV DNA in both thymi and bursae over the same period. At 35 days of age, virus was detectable by polymerase chain reaction in 16 of 20 chickens, and 7 of 20 had detectable antibodies. By 42 days of age, virus was detectable in 18 of 20 chickens, and 18 of 20 had antibodies to CAV. We observed a decrease in relative thymic weights beginning at 35 days of age, coincidental withthe detection of CAV in the thymus. Bursal sizes began to decrease at 28 days of age, coincidental with a rise in antibody titers to infectious bursal disease virus. In this study, we demonstrated that under typical field conditions CAV infections in broilers have unique dynamics unlike those reported in egg laying strains of chickens managed under specific-pathogen-free conditions.     

Effect of dietary sorbitol on the performance of broilers

1. The effect of dietary sorbitol on the performance of broilers was investigated. Male and female broilers were given a control diet or a sorbitol diet (100 g/kg diet) ad libitum from 29 to 57 d of age. 2. Body weight gain, food intake, food efficiency and the ME values of the diets were not significantly different. Absolute and relative weights of abdominal fat were significantly reduced in birds given the sorbitol diet. 3. Compared to the control diet, the diet containing sorbitol lowered the serum glucose, total cholesterol and very low density lipoprotein concentrations.     

鸡α-干扰素对罗曼雏鸡免疫功能的影响

为研究鸡α-干扰素对罗曼雏鸡免疫功能的影响,将60羽健康1日龄罗曼雏鸡随机分为2组,即对照组、试验组。试验组鸡于1日龄胸肌注射鸡-α干扰素,0.5 mL/羽;对照组鸡同期每羽注射生理盐水0.5 mL。试验开始后,于第4 d、8 d、12 d、16 d、20 d对鸡进行翅下静脉采血,并于20日龄剖杀摘取免疫器官。研究表明,鸡注射α-干扰素后,其外周血液ANAE+T淋巴细胞百分率和鸡脾相对湿重显著高于对照组,鸡α-干扰素在一定范围内可提高雏鸡免疫功能。     

Comparisons of the skeletal systems of growing broiler and laying strain chickens

Skeletal systems of growing broiler and laying strain chickens were compared in an attempt to establish whether the rapid growth rates of broilers lead to qualitative or quantitative skeletal deficiencies. Qualitative comparisons included studies of bone histology and of bone ash, density and compression strength. Quantitative comparisons related bone weight to body weight. Bone “ matured “ very rapidly, as judged by its density, ash content and weight relative to bird weight in the first fortnight of life and thereafter more slowly in both broilers and laying strain birds. After the age of I week bones “ matured “ mainly by replacement of water by mineralised osteoid—the degree of mineralisation of osteoid being a less important factor in bone “ maturation “. There were no significant differences from the viewpoint of either quality or quantity between the skeletal systems of broilers and laying strain birds of the same age. At equal body weights, however, broilers had skeletal systems which were both qualitatively and quantitatively less “ mature “ than those of laying strain birds. These differences were most marked during early life when the rate of skeletal “ maturation “ was high.     

胚蛋注射谷氨酰胺对肉仔鸡早期免疫器官的影响

选用已孵化18 d的肉仔鸡活胚蛋240枚,随机分成4个处理组,每个处理6个重复,每个重复10枚蛋.处理组Ⅰ注射1 mL 7.5 g/L生理盐水作为对照,处理组Ⅱ、Ⅲ、Ⅳ分别向鸡胚羊膜腔内注射质量浓度为5、10 mL/L和15 mL/L的谷氨酰胺营养液1 mL.结果表明,胚蛋注射谷氨酰胺对3日龄肉仔鸡的胸腺、脾脏和法氏囊...     

Dietary vitamin E (alpha-tocopherol acetate) and selenium supplementation from different sources: performance, ascites-related variables and antioxidant status in broilers reared at low and optimum temperatures

1. This study compared the effect of dietary supplementation with organic or inorganic selenium (Se) sources plus control amounts or large amounts of vitamin E (alpha-tocopherol acetate) in broilers raised at control (20 to 24 degrees C) or low (14.5 to 16.8 degrees C) temperatures after 2 weeks of age. 2. The following dietary treatments were used from one day old. Diet 1, the control diet, comprised a commercial diet containing 0.15 mg/kg inorganic Se and 50 mg vitamin E/kg feed. Diet 2 was the same as diet 1, supplemented with 0.15 mg/kg inorganic Se. Diet 3 was the same as diet 2 but was supplemented with 200 mg/kg vitamin E. Diet 4 was the same as diet 1, but inorganic Se was replaced with 0.30 mg/kg organic Se. Diet 5 was the same as diet 4, supplemented with 200 mg/kg vitamin E. 3. Low temperature reduced the growth rate of broilers; however, at 6 weeks, there were no differences in the body weights of birds fed on organic Se supplemented diets housed at low or control temperature. The feed conversion ratio was significantly affected by low temperature but not by diet. The heterophil/lymphocyte ratio was higher in chicks after one week in the cold, indicating mild stress. Blood triiodothyronine levels were significantly higher in birds after 1 and 4 weeks in the cold but thyroxin was not affected. 4. Organic Se supplementation increased relative lung weight at the control temperature, which might lead to greater respiratory capacity. Relative spleen weight significantly decreased in broilers fed diets supplemented with inorganic Se under cold conditions, a possible indication of chronic oxidative stress. 5. At the low temperature, supplementation with organic Se alone, or with inorganic Se and vitamin E increased glutathione peroxidase (GSHPx) activity and glutathione (GSH) concentration in the liver of broilers, which may indicate increased activity of birds' antioxidant defence against suboptimal environments.     

Haematological characteristics predicting susceptibility for ascites. 2. High haematocrit values in juvenile chickens

1. Male broilers of two different genetic stocks, a pure broiler sire line (A) and commercially available Ross broilers (B), were used to study the effect of differences in haematocrit values in 12-d-old chickens on the development of ascitic symptoms. Body weight gain (BWG), feed intake (FI) and feed conversion ratio (FRC) were measured from 2 to 5 weeks of age. Mortality was recorded from 2 to 6 weeks. The birds were kept at a low ambient temperature to stimulate the incidence of ascites. 2. From each stock 32 birds with the highest (High Ht) and 32 birds with the lowest (Low Ht) haematocrit values in venous blood were selected at 12 d of age for an examination on susceptibility for the ascites syndrome at 5 weeks. 3. At 2 weeks 448 birds per stock (including High Ht and Low Ht birds) were allotted to 32 floor pens (1 High Ht and 1 Low Ht in each pen). Venous blood samples were taken weekly in High Ht and Low Ht birds for haematocrit measurements and at week 5 also thyroid hormone (T3, T4) concentrations in plasma were measured. At 5 weeks all High Ht and Low Ht birds were examined post-mortem and arterial pressure index, heart weight, lung weight and liver weight (all relative to body weight) were recorded. High values for arterial pressure index, relative heart and liver weights and low values for relative lung weights and plasma thyroid hormone were considered to be indicators for ascites susceptibility. 4. Stock A, with the highest ascites mortality, had lower values for BWG and FCR than stock B. Throughout, a clear difference in Ht values between High Ht and Low Ht birds was maintained. No significant effects of 12-d haematocrit values were found on the incidence of ascitic symptoms until week 5. High Ht values tended to correlate with low relative lung weights and low plasma T3 concentrations in High Ht birds. 5. Within the groups of selected birds, there was an effect of stock on ascitic symptoms (arterial pressure index, relative heart weight and T3 values) at week 5. This is consistent with a higher ascites mortality in flock A than in flock B, over the whole period up to 6 weeks. Until 4 weeks both A and B were similar with respect to mean Ht values of High Ht and Low Ht groups. After 4 weeks Ht values were very high in the High Ht birds of stock A, possibly as a result of the susceptibility for ascites of stock A. There was a significant interaction between stock and Ht values on the ascites-related variable arterial pressure index. Only in stock A was high arterial pressure at 5 weeks related to high Ht values at d 12. 6. Overall it was concluded that a high Ht in blood of juvenile chickens has limited practical value in predicting incidence of ascites at 5 weeks of age.     

Polysaccharidase preparations added to a wheat-based diet: effects on performance and digestive parameters of broiler chickens held at three different locations

1. Three experiments of 39 d were simultaneously conducted to assess the efficacy of three carbohydrase combinations on performance, apparent nutrient digestibility, intestinal morphology and digestive organ relative weights of chickens fed on a wheat-based diet. 2. Experiment 1 was performed under laboratory conditions, with the birds housed in cages. In experiment 2, the birds were placed in floor pens built in a commercial farm, and raised with their contemporaries at the farm. In experiment 3, broilers were reared under industrial management circumstances in commercial farms. A two-phase feeding programme was used: starter from 1 to 21 d of age and finisher from 22 to 39 d. The basal diet without supplementation (BD) and three enzyme preparations (BDF, BDP and BDR) were evaluated. 3. No differences in growth traits were observed among treatments in experiments 1 and 2. 4. When overall growing period was evaluated, all enzyme combinations improved apparent DM ileal digestibility of feed in the three experiments, but significant differences were only found in experiments 2 and 3. For this same period, an increase in apparent CP ileal digestibility of broiler chickens fed supplemented diets against the control group was found in experiment 3. Moreover, a significant greater apparent ileal fat digestibility in the enzyme treatments compared with the control group was shown when broilers were raised under industrial conditions (experiment 3). 5. Enzyme combinations had no effect on villus heights and crypt depths of broilers in experiment 1, whereas, in experiment 2, a greater villus height was found in BDF and BDP treatments than in control birds. 6. There were no differences in digestive organ relative weights among dietary treatments except for pancreas in experiment 1.