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PubMed2005

Effects of dietary coenzyme Q10 supplementation on hepatic mitochondrial function and the activities of respiratory chain-related enzymes in ascitic broiler chickens.

1. One hundred and sixty 1-d-old Arbor Acre male broiler chicks were fed with maize-soybean based diets for 6 weeks in a 2 x 2 factorial experiment. The factors were CoQ10 supplementation (0 or 40 mg/kg) and Escherichia coli lipopolysaccharide (LPS) challenge (LPS or saline). 2. CoQ10 was supplemented from d 1. From d 18, the chickens received three weekly i.p. injections of LPS (1.0 mg/kg BW) or an equivalent amount of sterile saline as control. From d 10 on, all chickens were exposed to low ambient temperature (12 to 15 degrees C) to induce ascites. 3. The blood packed cell volume and ascites heart index of broiler chickens were reduced by dietary CoQ10 supplementation. Mitochondrial State 3 and State 4 respiration, respiratory control ratio and phosphate oxygen ratio were not changed, but H+/site stoichiometry of complex II + III was elevated by dietary CoQ10 supplementation. 4. Cytochrome c oxidase and H+-ATPase activity were increased by CoQ10 supplementation, whereas NADH cytochrome c reductase and succinate cytochrome c reductase were not influenced. Mitochondrial anti-ROS capability was increased and malondialdehyde content was decreased by CoQ10 supplementation. 5. The work suggested that dietary CoQ10 supplementation could reduce broiler chickens' susceptibility to ascites, which might be the result of improving hepatic mitochondrial function, some respiratory chain-related enzymes activities and mitochondrial antioxidative capability.

Animal Feed↗

PubMed2005

The effect of conditioning temperature and exogenous xylanase addition on the viscosity of wheat-based diets and the performance of broiler chickens.

1. A total of 1920 Ross broiler chicks were used in a 6 treatment by 8 replicate growth study to investigate the effect of conditioning temperature and exogenous xylanase addition on diet characteristics and bird performance. 2. Increasing conditioning temperature from 80 to 90 degrees C increased the viscosity of the diets by approximately 6 mPa.s and reduced body weight gain of the broiler chickens by 7%. 3. Furthermore, there was a significant interaction between temperature and the addition of exogenous xylanase, with a proportionately greater positive response to added xylanase in the diets that were pelleted at higher temperatures. 4. Addition of exogenous xylanase also increased the proportion of soluble arabinoxylan in the feed and reduced dietary viscosity, which is likely to be related to the degree of polymerisation of the soluble carbohydrate. 5. These results suggest that conditioning temperature should be considered as a factor when attempting to predict the response of broilers to added xylanase, especially when high-viscosity or 'low-quality' wheat is being used. 6. It can be concluded that pelleting wheat-based diets above 80 degrees C can compromise bird performance and that, if higher temperatures are to be employed, the use of exogenous xylanase is critical to maintain productivity.

Animal Feed↗

PubMed2005

Cytokine responses in broiler lines that differ in susceptibility to malabsorption syndrome.

1. Based on earlier studies it was hypothesised that there is an immunological basis for the differences in susceptibility to malabsorption syndrome (MAS). A study was conducted to investigate base-line and MAS-induced cytokine levels in the intestine of broilers that differ in MAS susceptibility. 2. The transcription of cytokine mRNA in the intestine was quantified using a real-time polymerase chain reaction (PCR) method. At different time points after disease induction the intestines of broilers were investigated for expression of interleukin (IL)-2, IL-6, IL-8, IL-18 and interferon (IFN)-gamma. Age-matched non-MAS-induced chickens served as controls. 3. Control chickens from a MAS-resistant line had higher concentrations of mRNA for IL-2, IL-6, IL-18 and IFN-gamma in the small intestine while no difference between the lines was found for IL-8. After induction of MAS the relative amounts of IL-2, IL-6, IL-8 and IFN-gamma mRNA increased more in the intestines of the susceptible line than in the gut of the resistant line. 4. We suggest that differences in cytokine mRNA in the base-line situation and in MAS-induced conditions indicate a difference in immune response regulation in the two broiler lines. This difference in response could lead to the difference in susceptibility to MAS.

Aging↗

PubMed2006

High-fibre pelleted rations decrease water intake but do not improve physiological indexes of welfare in food-restricted female broiler breeders.

1. A 3x2 factorial experiment was conducted with three diets and two lines of broiler breeder females to evaluate the contribution of low-energy rations for improving the welfare of feed-restricted birds during rearing. Experimental diets were fed from 6 to 16 weeks of age and were created by diluting a conventional grower (Control) ration containing 11.0 MJ ME/kg with 200 (8.8 MJ ME/kg) or 400 (6.6 MJ ME/kg) g oat hulls/kg using Optimoist to facilitate the pelleting process. Welfare was assessed by changes in behaviour and physiological variables at 8, 12 and 16 weeks of age. Birds were fed restricted quantities of feed to meet recommended body weight targets. 2. There was a decrease in the proportion of observations of drinking and an increase of preening in birds fed on the two experimental diets compared with the control. There was a linear decrease in litter moisture and the number of litter changes with increasing diet dilution, and water intake at 12 weeks was higher in the control than in the two experimental diets. There were no changes in physiological indexes of welfare (heterophil-lymphocyte ratio, plasma corticosterone and antibody responses) associated with the dietary treatments. 3. There were no important differences in the growth, behaviour or physiological responses to dietary treatment between the two lines of broiler breeders. Changes with age were similar to those reported in other experiments. 4. It was concluded that low-energy pelleted diets would improve litter conditions but not improve indexes of welfare in feed-restricted broiler breeders.

Animal Feed↗

PubMed2006

Generation of hydroxyl radicals during ascites experimentally induced in broilers.

Increased metabolic rates, pulmonary hypertension and cardiac dysfunction are the most important features of the ascites syndrome in broiler chickens. However, the mechanism of cell injury causing the pathogenesis of the syndrome is not clearly understood. Our study aimed to examine the generation of hydroxyl radicals (OH*) in broiler chickens experiencing ascites. The hundred and fifty 1-d-old chickens were purchased from a local hatchery and reared in an open poultry house for 46 d. They were divided at random into three groups and ascites was induced in two groups by exposing them to low temperature or administration of triiodothyronine (T(3)). The third group served as control and was reared normally. Haematological, biochemical and pathological tests were used to determine the incidence of ascites: including total red blood cell (RBC), packed cell volume (PCV), release of alanine transaminase (ALT) and aspartate transaminase (AST) and ratio of right ventricular weight to total ventricular weight (RV/TV). A salicylate hydroxylation method was used to examine the generation of hydroxyl radicals (OH*) in treated groups. TWo hydroxylated salicylic acid metabolites, 2,3- and 2,5-dihydroxy benzoic acid (2,3- and 2,5-DHBA), were measured by HPLC to detect the generation of OH*. An ascites syndrome was observed in T(3) and low-temperature treated groups, as shown by necropsy changes and increases in f RBC, PCV, ALT, AST and the ratio of RV/TV. Concentrations of 2,3- and 2,5-DHBA were increased in groups experiencing ascites compared to control group. It is suggested that reactive oxygen species that is OH* ions, may be involved in the pathogenesis of the ascites syndrome in broiler chickens.

Alanine Transaminase↗

PubMed2006

Evaluation of endothelial and inducible nitric oxide synthase mRNA expression in the lung of broiler chickens with developmental pulmonary hypertension due to cold stress.

To clarify the effect of cold-induced pulmonary hypertension on endothelial and inducible nitric oxide synthase (eNOS and iNOS) mRNA expression in the lung of broiler chickens, semi quantitative reverse transcription-PCR was performed on total RNAs isolated from lungs of the broiler chickens exposed to 5 weeks of cold stress. The eNOS gene was expressed increasingly with the increasing age during the rearing period. Comparing the treatment group with its related control group eNOS was expressed significantly only at d 21. Expression of iNOS mRNA also increased in both control and treatment groups with increasing age until d 28 and then decreased at d 35 and 42. Comparing the treatment group with its control group, iNOS mRNA level was significantly higher at 21 d of age in the cold-exposed chickens. It was concluded that, although cold exposure could significantly increase eNOS and iNOS gene expression, cold-induced pulmonary hypertension is not associated with significant variations of eNOS and iNOS expression in the lungs of broiler chickens.

Aging↗

PubMed2006

Changes in pulmonary arteriole protein kinase calpha expression associated with supplemental L-arginine in broilers during cool temperature exposure.

The present study was conducted to examine the effect of supplemental L-arginine on pulmonary arteriole protein kinase Calpha (PKCalpha) expression in broilers exposed to cool temperature, to investigate further the molecular mechanisms of supplemental L-arginine on modulating pulmonary vascular functions in hypertensive broilers. Broilers were subjected to sub-thermoneutral (cool) temperature to induce pulmonary hypertension syndrome (PHS), and an additional 10 g/kg L-arginine was added to the basal diet to evaluate the effects of supplemental L-arginine on PHS mortality, plasma nitric oxide (NO) production and pulmonary arterioles PKCalpha expression. Supplemental L-arginine reduced PHS mortality but did not affect right/total ventricle (RV/TV) ratios in clinically healthy birds. Birds fed additional L-arginine had increased plasma NO and decreased PKCalpha protein expression in pulmonary arterioles; NO production was negatively correlated with PKCalpha expression. These results demonstrated that supplemental L-arginine diminished PKCalpha expression in birds exposed to cool temperature. It is suggested that NO-induced loss of PKCalpha expression might be partially responsible for its effects on dilating pulmonary vasculature and inhibiting pulmonary vascular remodelling in vivo.

Animals↗

PubMed2006

Effects of aflatoxin B1 and fumonisin B1 on body weight, antibody titres and histology of broiler chicks.

1. Our objective was to evaluate the toxic effects of aflatoxin B1 (AFB1) and fumonisin B1 (FB1), administered singly or in combination to broilers. 2. Feeds were prepared with concentrations equal to 0, 50 and 200 microg AFB1/kg, and/or 0, 50 and 200 mg FB1/kg, and offered to broiler chicks from 8 to 41 d of age. The experimental design was totally randomised, in a 3 x 3 factorial arrangement with 9 treatments and 12 birds per treatment. Animals were vaccinated against Newcastle disease on d 14 of life and killed at 41 d. 3. Compared with controls, all mycotoxin-treated groups at 41 d had lower body weight and weight gain, and higher relative heart weight. The relative weight of the liver increased only in birds fed diets containing 200 mg FB1, singly or in combination with AFB1. 4. At 35 d, all groups receiving mycotoxin-treated rations had reduced geometrical mean antibody titres, with birds from groups fed combinations of AFB1 and FB1/kg having even lower values, when compared to the other groups. 5. Histological changes were observed only in liver from birds fed mycotoxin-contaminated rations, and in kidneys of birds fed the diet containing 200 microg AFB1 and 200 mg FB1/kg. Main alterations included vacuolar degeneration and cell proliferation of bile ducts in the liver, and hydropic degeneration in renal tubules in the kidneys. 6. We concluded that AFB1 and FB1 in combination have primarily additive effects on body weight, liver structure and immunological response of broilers at the concentrations used.

Aflatoxin B1↗

PubMed2006

Effect of stachyose supplementation on growth performance, nutrient digestibility and caecal fermentation characteristics in broilers.

1. The objective of this study was to evaluate whether the oligosaccharide stachyose enhances gastrointestinal tract health by fermentation and proliferation of desirable bacteria species and thus affects growth performance and nutrient digestibility in broilers. 2. A total of 432 1-d-old male Arbor Acres (AA) broilers were randomly allocated to one of 6 treatments, with 12 replicate pens per treatment and 6 birds per pen. Chicks were fed a maize-hamlet protein 300 (HP300) basal diet with 0, 4.0, 8.0, 12.0 or 16.0 g/kg stachyose. A sixth diet contained no HP300 but soybean meal (SBM) and provided 8.7 g/kg stachyose and 3.1 g/kg raffinose. The duration of the study was 42 d. 3. Stachyose contents above 12.0 g/kg depressed group body weights, average daily gain and feed/gain but not feed intake during the whole experimental period. Broiler growth decreased linearly and quadratically with increasing stachyose content. No differences were detected between diets supplemented with 12.0 g/kg stachyose and SBM. 4. Nutrient digestibility tended to decrease but not significantly with increasing stachyose. 5. Stachyose content had no significant positive effects on caecal pH, microflora population and the resulting short-chain fatty acid (SCFA) metabolites during the 42 d experiment, with only butyrate differing significantly in the initial period.

Animal Feed↗

PubMed2006

Effects of methionine and betaine supplementation on growth performance, carcase composition and metabolism of lipids in male broilers.

1. This study was conducted to investigate the effects of methionine and betaine supplementation on growth performance, carcase composition and lipid metabolism in growing broilers. 2. A total of 450 commercial broilers, 22 d of age, were randomly allocated to three groups, each of which included three replicates (50 birds per replicate). The groups received the same methionine-deficient diet supplemented with 0 or 1 g/kg methionine, or 0.5 g/kg betaine, respectively. 3. Methionine and betaine supplementation significantly improved weight gain and feed conversion. Supplemental methionine and betaine also significantly increased breast muscle yield and decreased abdominal fat content. Meanwhile, addition of methionine and betaine significantly increased the contents of creatine and free carnitine in liver, the activity of hormone-sensitive lipase in abdominal fat and the concentration of free fatty acid in serum, whereas uric acid concentration in serum was significantly decreased. 4. The results of this study suggest that betaine can spare methionine in its function as an essential amino acid and is as effective as methionine in improving performance and carcase quality of growing broilers if the diet is moderately deficient in methionine. The decrease in abdominal fat may be due to the increased carnitine synthesis in liver and hormone-sensitive lipase activity in abdominal fat.

Animal Feed↗

PubMed2006

Bone breaking strength and apparent metabolisability of calcium and phosphorus in selected and unselected broiler chicken genotypes.

1. The present study examined the bone strength and apparent mineral metabolisability of a selected broiler chicken compared with those of a relatively unselected genotype. 2. Selected (SB) and unselected genotypes (UB) were reared under standard conditions and were fed on either a high quality (HQ) or a low quality (LQ) diet. Tibiotarsi samples were collected at 42 d from SB and compared to tibiotarsi from UB of the same age and the same body mass (BM). 3. Bones were assessed for: bone breaking strength (BBS), morphology (weight and length), and both organic (OM) and inorganic content (ASH). Apparent dry matter digestibility and the coefficient of apparent metabolisability of calcium and phosphorus were determined at the same BM. 4. The BBS of SB (214 +/- 9 N) was greater than that of same-age UB (119 +/- 8 N) but the same as that of same-BM UB (218 +/- 10 N). At the same age, the SB had stronger, heavier bones with more ash and organic matter per unit length of tibiotarsus than UB. At the same BM, the tibiotarsi of the SB were shorter and lighter, with a higher ash and a similar organic content than the bones of the UB. At the same BM, BBS was about 15% lower in both genotypes fed on the LQ compared to the HQ diet. 5. The coefficients of apparent metabolisability of calcium and phosphorus were the same in both genotypes when fed on the HQ diet, but were lower in the SB than in the UB genotype when the birds were given the LQ diet. 6. The tibiotarsi of the selected broilers were stronger, or at least as strong, as those of the unselected broiler genotype, which may be due to similar levels of apparent calcium metabolisability of the selected chickens.

Animal Feed↗

PubMed1976

Urea and aspartic acid supplementation of low-protein broiler diets.

1. L-Aspartic acid does not seem useful as a protein surrogate in conventionally formulated low-protein diets for broiler chicks. 2. Urea as a protein substitute does not enhance the value of conventional broiler diets. 3. Urea does not improve broiler diets that have been supplemented with fish meal or crystalline amino acids to satisfy requirements for all indispensable amino acids. 4. Urea is absorbed into the bloodstream, but is not assimilated into body proteins.

Animal Feed↗

PubMed1978

The inheritance of tibial dyschondroplasia in broilers.

A breeding programme to develop a line of chickens with a high incidence of tibial dyschondroplasia (TD) from Australian broiler stock is described. Despite the absence of a control flock, this programme has demonstrated that selection in a broiler population can rapidly increase the incidence of TD. There was consistent circumstantial evidence of the presence of a major sex-linked gene, the recessive allele of which is associated with an increased incidence of TD. The realised heritability estimates (obtained in the absence of a control flock) consistently exceeded 1.00, suggesting the presence of an environmental trend favourable to the onset of TD over the four generations of this investigation. There was a high maternal component or dominance genetic component, or both, for the inheritance of TD in the final generation, suggesting that environmental factors associated with the female parent line may influence the incidence of TD in broilers.

Animals↗

PubMed1978

Twisted legs in broilers.

The effect of various factors on the incidence of leg abnormalities, with particular reference to twisted leg, in broilers was studied. The incidence of twisted legs was influenced by strain and for males was twice that for females. There was also a higher incidence in cages than on litter with the type of cage floor having an effect: broilers reared on floors of metal wire and perforated sheets had more leg problems than those reared on plastic mats and plastic-covered wire. Although vitamin and mineral supplementation had no effect on caged broilers, a restriction of metabolisable energy (ME) intake during the first 14 d after hatching halved the frequency of leg abnormalities compared with those fed ad libitum. Studies of cage size and location of water suggested that a lack of exercise increases the incidence of leg abnormalities.

Animals↗

PubMed1983

Energy metabolism of groups of broiler breeders in open-circuit respiration chambers.

Energy metabolism of broiler breeders housed in groups was measured in large open-circuit respiration chambers. The design, function and calibration of the chambers are described. Each of the three chambers has a capacity for 24 pullets or adult layers, or 16 adult broiler breeders. Control of ventilation rate is by calibrated choked-flow nozzles. Before experiments were started the system was assessed by CO2 infusion and recovery and ethanol combustion studies. Percentage CO2 recoveries were greater than 98 of infused and the mean (+/- SD) quotient of CO2 produced to O2 consumed from the combusion of ethanol was 0.67 (+/- 0.02). Forty-eight broiler breeder hens in lay were placed in the respiration chambers (16 per chamber) and fed at different rates from around maintenance to about twice this value. The energy required for maintenance (MEm) was 365 kJ/kgW0.75 d and the efficiency of utilisation of metabolisable energy (ME) for production (kp) was 0.70. Starvation heat production was about 350 kJ/kgW0.75 d and was shown to affect the derived values of the energetic parameters when included in the relationship between retained energy and metabolisable energy intake. Published results were recalculated and found to support this.

Air↗

PubMed1986

Efficiency of effect of high ambient temperatures on food utilisation in male broilers.

The effect of ambient temperatures above 28 degrees C on the efficiency of food utilisation were studied in 7 consecutive flocks of male broilers, grown in a cross-ventilated controlled environment poultry house. The best correlation between the food:gain ratio and temperature was obtained when the latter was expressed as degrees-h (Th), that is, the aggregate of the differences between the ambient temperature and 28 degrees C, measured hourly. The equation: Food:gain ratio = 2072 + 0.125 X Th, demonstrates clearly the negative effect of high temperatures on food:gain ratio in broilers. It might be helpful for the broiler industry when evaluating the need for and planning of cooling devices for poultry houses.

Animal Nutritional Physiological Phenomena↗

PubMed1987

Comparisons of time intervals and plasma LH concentrations during the ovulatory cycle of broiler breeder hens maintained under either a 24 h light:dark cycle or continuous light.

The possibility that egg production in broiler breeder hens may be increased by selection for reduced oviposition interval under continuous light was investigated by comparing the pattern of pre-ovulatory releases of plasma luteinising hormone (LH) and the associated ovipositions in the same broiler hens maintained under normal cycles (15.25 h light/d) or continuous light. The lighting conditions had no effect on plasma concentrations of LH before and at the pre-ovulatory LH peak in first, mid-sequence or terminal ovulatory cycles. Plasma LH concentrations were similar during first, mid-sequence and terminal ovulatory cycles. Mid-sequence oviposition intervals and the interval between a mid-sequence LH peak and its associated oviposition were longer under continuous light than under normal lighting. Pre-ovulatory releases of LH occurred during a restricted period of day in both lighting conditions. Under continuous lighting they were probably entrained by the daily pattern of restricted feeding. Any selection programme for reduced oviposition interval under continuous lighting in broiler breeder hens should take into account the entraining effects of the daily pattern of feeding.

Animals↗

PubMed1989

Influence of oxidised dietary oil and antioxidant supplementation on membrane-bound lipid stability in broiler meat.

1. The effects of oxidised oil, dietary alpha-tocopherol and BHA/BHT-supplementation on the fatty acid composition of mitochondrial, microsomal and soluble protein fractions of broiler muscles, and on their lability to metmyoglobin/hydrogen peroxide-catalysed peroxidation were investigated. 2. Oxidised oil in the broiler diets induced rapid oxidation of the membrane-bound lipids and decreased their stability towards metmyoglobin-hydrogen peroxide-catalysed peroxidation. 3. Supplementation of the broiler diets with alpha-tocopherol increased the alpha-tocopherol concentrations in the microsomal and soluble protein fractions of the dark meat as well as the soluble protein fraction of the white meat. This, in turn, stabilised the membrane-bound lipids against metmyoglobin/hydrogen peroxide-initiated peroxidative changes.

Animals↗