SEARCH · PubMed Health

Results for “Broilers”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 415 records · Page 23Linked to original sources

PubMed1993

Comparison of calpain and calpastatin activities in skeletal muscle of broiler and layer chickens.

1. The objective of this study was to estimate the difference between broiler and layer chicks in the activities of calpain and calpastatin (inhibitor of calpain) in breast muscle. Differences between broilers and layers in body weight, daily gain at 3 weeks of age and fractional growth rate (FGR) during 2 and 3 weeks of age were statistically significant (P < 0.01). 2. Calpain and calpastatin activities were measured at three weeks of age with alkali-denatured casein as a substrate. The m-calpain (calpain activated by millimolar calcium concentration) activities in units/g muscle and units/mg extractable muscle protein were 0.779 and 0.353 for broilers, and 1.042 and 0.440 for layers, respectively. The calpastatin activities in units/g muscle and units/mg extractable muscle protein were 0.332 and 0.153 for broilers, and 0.262 and 0.112 for layers, respectively. 3. Broilers with high FGR showed low m-calpain and high calpastatin activities. In contrast, layers with low FGR showed high m-calpain and low calpastatin activities. 4. These results suggest that m-calpain and calpastatin activities in skeletal muscle vary between breeds which have different rates of muscle production.

Animals↗

PubMed1995

The evaluation of the growth parameters of six strains of commercial broiler chickens.

1. An experiment was conducted to measure the potential growth of males and females of 6 commercial broiler stocks, from which information the growth rates of these genotypes could be characterised by the Gompertz growth equation. 2. Feeding and environmental conditions were designed to ensure that the birds remained comfortable throughout their growing period, which was to 26 weeks of age. A choice of diets differing in protein content was offered from 3 weeks of age. Because of leg weaknesses among the male broilers after 11 weeks of age, and because many females reached sexual maturity at about this age, the growth analyses were conducted on weights collected up to 11 weeks of age only. At this weight, broilers had achieved approximately 0.76 of their mature weight. 3. Birds representative of each genotype were killed for carcase analysis at weekly intervals to 9 weeks of age, and every two weeks thereafter. The contents of gut fill, feathers, water, protein, ash and lipid were measured on each of these birds; from these, equations were derived for each genotype that allowed the estimation of the weights of these components in the birds remaining on the experiment. 4. The body weight, body protein, body water and feather weight of the 12 genotypes were described in terms of the mature weight of these components, their rates of maturing and the time taken to reach the maximum rate of growth of each component. These descriptors of the growth of each component were then compared between genotypes. 5. No statistically significant differences existed in the rates of maturing of the different genotypes, either between strains or between sexes. Highly significant differences were evident between strains and between sexes in their mature weights, indicating that their rates of growth differed. 6. Estimates of mature feather weights indicated that this component of the body comprised 0.062 and 0.050 of the mature body weight of female and male broilers respectively. The protein content of feathers increased steadily, and the water content decreased steadily, throughout the growing period. 7. Differences between the genotypes evaluated in this experiment indicate that the nutrient and environmental requirements of these genotypes would differ. A description of each genotype, therefore, is an essential component of any simulation model that attempts to determine the optimum economic feeding programme and environmental conditions for broilers.

Aging↗

PubMed1997

Effect of the method of killing, interval between killing and neck cutting and blood vessels cut on blood loss in broilers.

1. Broiler chickens were killed using 90% argon in air, or 30% carbon dioxide and 60% argon in air or 120 mA per bird in a waterbath with a 50 Hz alternating electric current. Ventral or unilateral neck cutting was performed at 1, 3 or 5 min after killing. In addition, a group of broilers was stunned with 120 mA per bird in a waterbath using 1500 Hz alternating current and were bled out-with a ventral neck cut within 20 s from stunning. 2. Blood leaving the neck wound was collected in a bin placed on an electronic balance and a computer program calculated the cumulative blood loss up to 100 s after neck cutting. 3. Bleed-out was significantly affected by killing method and time of neck cutting. Broilers killed with the carbon dioxide-argon mixture bled-out less than those killed with argon or 50 Hz electric current. When compared with the 1 min neck cutting interval, a delay of 3-or 5 min resulted in a lower bleed-out. High frequency electrical stunning and ventral neck cutting within 20 s resulted in a slightly higher bleed-out than those recorded for the killing methods. However, within argon killing, a delay of 3 or 5 min in ventral or unilateral neck cutting had no significant effect on the bleed-out. In broilers killed with the carbon dioxide-argon mixture a 3 min delay in ventral neck cutting or a 5 min delay in unilateral neck cutting resulted in lower bleed-out. 4. Neck cutting of broilers within 5 min after argon killing or 3 min after killing with the carbon dioxide-argon mixture would result in a satisfactory bleed-out.

Abattoirs↗

PubMed1997

Comparison of food intake, rate of consumption, pecking activity and behaviour in layer and broiler breeder males.

1. The food intake, rate of food consumption (g/min) and behavioural time budgets of individually caged broiler and layer (white egg) males were compared in the early morning (1.5 to 3.5 h after onset of photoperiod) and afternoon (5.5 to 7.5 h after photostimulation) on 4 different days at 11 to 12 weeks of age. Correlations among rate of consumption, the proportions of time on different activities and previously estimated scores for fearfulness were calculated. 2. Food intake and rate of consumption were two-fold greater in broilers than in layers. The proportion of time spent feeding in the morning was lower in layers compared with broilers and was similar in the afternoon. Rate of consumption was higher in the morning than in the afternoon in both lines. 3. Overall, a similar proportion of time was spent feeding, standing and sitting in both lines. The birds were more likely to be sleeping (eyes closed) in the afternoon than in the morning. 4. The proportions of time spent on preening, pecking and stereotypic pacing were greater in layers than in broiler breeders. The proportion of time spent drinking tended to be higher in broiler breeders than layers. 5. Two measures of fearfulness, aversion to a looming human and a novel rod were respectively positively and negatively correlated to time drinking and stereotypic pacing. 6. The time spent in stereotypic pacing was negatively related to rate of consumption and time spent preening. 7. The results suggest that low food intake is associated with increased arousal, fear and frequent feeding and drinking. There was no evidence that beak related activity was related to fearfulness.

Aggression↗

PubMed1997

Effect of choice feeding on the performance of broilers.

1. Male broilers from, 21 to 56 d of age were fed their diet either mixed as pellets or mash, or as separate ingredients presented on a free-choice basis, to determine whether feeding method affected growth, carcase composition or profitability to 56 d of age. 2. The 12 treatments were: 2 completely balanced diets fed as mash or pellets, 8 choice fed diets containing maize or sorghum as the energy source (whole or mash) and protein concentrate (pellets or mash) and 2 unbalanced mixed mash diets containing 50% grain (maize or sorghum) plus 50% protein concentrate. 3. For the choice treatments, one food, grain (maize or sorghum) or protein concentrate (mash or pellets), was placed in each feeder. Broilers fed the complete pelleted or mash diet received the diet in both feeders. Food consumption was recorded weekly. Broilers were weighed at 42 and 56 d of age. 4. There were no significant differences between treatments and the pelleted control diet with regard to body weight, food consumed, food efficiency, carcase, ash, dressing percentage and mortality. 5. Choice fed broilers receiving the energy source as whole grains had larger gizzards while the higher protein diets (50/50) resulted in a higher carcase moisture and protein but lower carcase fat than the broilers fed the pelleted control diet. 6. The main advantage of choice feeding appears to be the economical savings of feeding whole grains as the energy source.

Analysis of Variance↗

PubMed1998

Effect of dietary administration of oil extracts from rosemary and sage on lipid oxidation in broiler meat.

1. Oxidation of meat and membrane from broilers fed on a diet containing 500 mg/kg rosemary and sage extracts was compared to meat and membrane oxidation from broilers receiving a control diet (not enriched with antioxidants) and a diet enriched in alpha-tocopheryl acetate (200 mg/kg). 2. After 9 d of refrigerated storage, thiobarbituric acid reactive substances of white meat from broilers fed on the control and the alpha-tocopheryl acetate-enriched diets were 0.51 and 0.25 mg malonaldehyde/kg meat, respectively. Values for meat from broilers fed on the diets containing the rosemary and sage extracts were in the range 0.30 to 0.35 mg malonaldehyde/kg meat, significantly lower than those from birds fed on the control diet. A similar trend was observed in the dark meat but differences were not significant at 9 d of storage. Similar trends were observed in raw samples stored at -20 degrees C for up to 4 months and in samples cooked at 70 degrees C and kept stored under refrigeration for up to 4 d. 3. The meat from broilers fed on the diet containing spice extracts had smaller concentrations of total cholesterol oxidation products (COPS) than meat from the control group (P < 0.05). Supplemental alpha-tocopheryl acetate reduced the COPS concentrations to a greater extent than did spice extracts (P < 0.05). 4. A similar trend was observed in microsomal fraction isolates, in which the rate of metmyoglobin/hydrogen peroxide-catalysed lipid peroxidation was lower in animals receiving spice extracts than in those fed on the basal diet.

Abattoirs↗

PubMed1999

Effect of light source and regimen on growing broilers.

The aim of this study was to determine the effect of different light sources and light schedules on the growth and quality of commercial broilers. In each experiment 810 broiler chicks were divided into 3 groups, 3 replicates per group. All were reared at 20 lux. Body weight and food consumption were recorded weekly. Experiment 1. Birds were reared under 3 light sources: incandescent light bulb, warm-white fluorescent light tube or warm-white mini-fluorescent light bulb. Experiment 2. Birds were reared on 3 light schedules. 23 h light and 1 h dark (23L: 1D) throughout; an increasing light schedule with initial 23L:1D then 8L: 16D increasing daylight gradually to 16L:8D or an intermittently increasing daylight schedule (16:8P) where light and dark periods were shorter but portioned to achieve the same total hours per day up to 16L:8D. Broilers reared under mini-fluorescent light bulb were heavier than those under fluorescent tubes or incandescent bulbs by 49 d. Until 42 d of age, photoperiod had no effect on growth. However, at 49 d broilers reared under 16:8P and 16L:8D regimens were heavier than those or 23L:1D. At 42 d, female broilers on 23L:1D, were heavier than those on 16L:8D and 16:8P. Mortality was higher in groups on 23L:1D than on 16L:8D on 16:8P. At 49 d incidence of leg condemnation was higher in the 16:8P group. However, skin damage was lower in this group than in those on 23L: 1D and 16L:8D.

Animals↗

PubMed1999

Performance, serum characteristics, carcase traits and lipid metabolism of broilers as affected by supplement of chromium picolinate.

1. This study investigated the effects of dietary supplementation with chromium picolinate on the performance, serum and carcase traits and lipid metabolism of broilers. In trial 1, 120 1-day-old broilers with an equal number of males and females were assigned at random to 4 groups with 3 replicates. Four treatments with dietary supplements of 0 (control), 800, 1600 and 3200 microg/kg of chromium picolinate were used. In trial 2, 6-week-old broilers (20) were used to determine how supplements of 0, 200, 400 and 800 microg/kg chromium in an incubation medium influence their hepatocyte lipogenic capacity and adipocyte lipolysis, in vitro. 2. Dietary supplements of 1600 and 3200 microg/kg chromium in broiler diets significantly increased food consumption (P<0.05); 1600 microg/kg markedly improved weight gain (P<0.05); 1600 and 3200 microg/kg groups showed increased liver lipid content (P<0.05). However, the abdominal fat content tended to decrease in these 2 groups. 3. Dietary supplements of 1600 and 3200 microg/kg of chromium decreased serum glucose and nonesterified fatty acids (NEFA) concentrations while increasing serum phospholipid content (P<0.05). Insulin concentration decreased only in birds receiving 3200 ppb chromium (P<0.05). Serum triacylglycerol (TG) clearance rate in chromium-supplemented groups was markedly enhanced (P<0.05). 4. In addition, chromium supplemented groups had increased serum HDL contents and also reduced serum VLDL and LDL contents (P<0.05). 5. Trial 2 indicated that lipogenesis from [U-14C]glucose by isolated hepatocytes was significantly enhanced by 400 ppb chromium (P<0.05). 6. The results from this study demonstrate that a supplement of 1600 microg/kg of chromium picolinate in the ration influences the growth, carcase, serum traits and lipid metabolism of broilers.

Adipocytes↗

PubMed1999

Higher lipid accumulation in broilers fed on saturated fats than in those fed on unsaturated fats.

1. Two experiments were conducted to assess the effect of fat sources differing in degree of saturation on the performance of and fat deposition in broiler chickens fed on isocaloric and isonitrogenous diets. 2. There were no differences in initial body weight between sexes but female broilers had lower daily gains (P<0.0001), final weights (P<0.0001) and food intakes (P<0.0001) than males. Abdominal fat pad weight was lower in male broilers than in female (P<0.001). 3. There were no significant differences in intake, weight gain, final body weight or food-to-gain ratios between birds fed on diets differing solely in the degree of fat saturation. Broilers fed on diets containing an animal fat blend or tallow had higher abdominal fat pad weight (P<0.001) and intramuscular lipid content (P=0.0085) than those fed on diets containing sunflower oil. 4. It was concluded that dietary fat saturation affects fat accumulation in broiler chickens.

Adipose Tissue↗

PubMed1990

Protection of broilers against Newcastle disease by hyperimmunisation of the dams.

A flock of broiler parents was hyperimmunised against Newcastle disease (ND) by subcutaneous injection of an experimental high-potency inactivated oil emulsion (IOE) vaccine in order to achieve high and long-lasting passive protection in broilers. During the egg production period mean log2 HI ND titre of the parents slowly decreased from 11.6 at 26 weeks of age to 10.0 at 53 weeks of age. Titres of day-old progeny paralleled those of their parents. Mean protection of broilers against mortality following challenge with Herts 33 virus at the ages of 1, 2, 3 and 4 weeks was 86%, 73%, 54% and 44%, respectively. As compared with the current Dutch situation, application of the high-potency IOE vaccine will significantly increase antibody titres in parent flocks and the level and duration of passive protection in broilers. It is concluded that passive ND protection of broilers by hyperimmunisation of the dams is realisable from an economic point of view and is suitable for low-risk areas.

Animals↗

PubMed2002

Anticoccidial vaccines for broiler chickens: pathways to success.

The use of live vaccines, either attenuated or non-attenuated, for the control of coccidiosis due to Eimeria infections in broiler breeder or layer chickens is well established. Use in broilers, however, has been slow to gain acceptance. This has been partly for economic reasons, but also because of perceived adverse effects on early chick growth, particularly with non-attenuated vaccines, and concerns about timely onset of protective immunity in such short-lived birds. This review describes advances in understanding of epidemiological factors and recent improvements of administration methods that have helped to allay these fears and to make the use of anticoccidial vaccines in broilers technically achievable. Topics discussed include: (1) types of commercially available vaccine, (2) vaccines in development, (3) vaccination methods and equipment, (4) basis of vaccine efficacy and immunogenic variation of parasites, (5) key factors in the survival, sporulation and dissemination of vaccinal oocysts, (6) descriptions and significance of patterns of litter oocyst accumulation and occurrence of intestinal lesions in vaccinated flocks, (7) rotation of anticoccidial vaccination and chemotherapy to restore drug sensitivity to resistant wild-type coccidia, (8) combinations of anticoccidial vaccination and chemotherapy, (9) interactions between coccidiosis and clostridiosis in broilers and compatibilities of potential control methods, (10) published performance data for live anticoccidial vaccines in broilers, (11) possible further developments of live vaccines.

Animals↗

PubMed2004

Maternal vaccination against subclinical necrotic enteritis in broilers.

The inclusion of antibacterial feed additives has until now been the major strategy for controlling Clostridium perfringens-associated necrotic enteritis in broilers. In the present study, the effect of maternal immunization against the disease was examined. Broiler breeder hens were injected intramuscularly with candidate vaccines based on C. perfringens type A and type C toxoids adjuvanted with aluminium hydroxide. Vaccination resulted in a strong serum immunoglobulin G response to C. perfringens alpha-toxin in parent hens, and specific antibodies were transferred to their progeny. Subclinical necrotic enteritis in broilers was induced under field conditions or in a disease model, and the occurrence of specific enteric and hepatic lesions was evaluated in randomly selected birds. In three experiments, estimates of odds ratio for developing such lesions were 0.23, 0.33 and 0.56 in maternally toxoid C-immunized broilers compared with non-immunized controls. In toxoid A-immunized birds, odds ratios were estimated at 0.41, 0.61 and 0.63. From these results, immunoprophylaxis seems to be an interesting alternative for the control of necrotic enteritis in broilers.

Age Factors↗

PubMed1985

[Initial research on the use of mixed corn grain and stalk silage in broiler fattening].

The suitability of a corn and cob maize silage (CCM) as a component rich in energy in the fattening ration was investigated in a growth experiment with male broilers. The CCM silage with a dry matter content of 60.2% contained the following substances determining its value (per 1 kg dry matter of the feed): 102 g crude protein, 61 g crude fibre and 682 energetic feed units for chickens (EFUc). CCM silage was either fed as a component of a feed mixture consisting of 70.5% CCM silage and 29.5% protein concentrate (all values of original substance) or both components of the ration were fed to broilers separately. The protein concentrate was composed as follows (values per kg): 650 g soybean oilmeal, 110 g fishmeal, 85 g tankage from rendering plants, 55 g torula yeast, 70 g mineral mixture and 30 g of a mixture of biologically active substances. The broilers of the control group received commercial fattening feed for broilers with coarse maize meal as cereal component. The feed mixture with CCM silage and separate CCM silage were accepted readily. When CCM silage and protein concentrate were offered alternatively, the same amount of CCM silage was consumed but 8% less protein concentrate. The broilers fed with CCM silage plus protein concentrate reached 96-97% of the live weight of the control animals (1.952 g/animal, 49th day), which received conventional feed, although their net energy intake was 10% lower. This proves a more favourable net energy expenditure for the test groups fed with CCM silage.

Animal Feed↗

PubMed1993

[Toasted rapeseed meal in broiler fattening diet].

A fattening trial of six week duration using male broiler chicks of the TETRA 82 genotype has been performed to evaluate the feeding value of rapeseed meal derived from the following rapeseed origins of so-called double-zero quality: Canola (Cananda), Jantar (Poland) and the new-bred East German-genotype BNW 1.43, each at a diet level of 12%. Moreover, the indigenous origin has been investigated at levels of 6 and 18% in practical broiler rations as a protein source instead of soybean meal (partial replacement). The fattening results (live weight development, intake and conversion of feed, mortality) do not show disadvantageous effects by the different rapeseed meal origins, and the various levels too. The chemical whole-body composition gives reduced fat and more protein in broiler's carcass at a diet level of 12 and 18% of BNW 1.43-rapeseed meal. Blood plasma levels of T3 and T4 have refered to beginning status of hypothyreodism, higher percentages of rapeseed mean had been fed. Weight of broiler's thyroid varied independtly of treatment. Also by the means of histometrical investigation of these glands the effects known for conventional rapeseed meals could be demonstrated, however in an important weakly extent. In comparison to discrepancies in the literature results regarding the possible inclusion of double-zero rapeseed meal in broiler diets, it seems a maximum diet level of 12% of toasted rapeseed meal of used qualities could be recommended for practical diet formulation (without of performance depressions). However, further investigations are be essential in these questions.

Animal Feed↗

PubMed1995

Effects of dietary sulfur amino acids and crude protein on the performance of finishing broilers.

The effects of different combinations of dietary methionine + cystine (Met + Cys) and dietary crude protein (CP) in finishing broilers were investigated in two growth studies. In Exp. 1, male broilers 29 to 42 days of age were fed 18 diets containing 16.9%, 18.7%, or 20.4% CP with six levels of Met + Cys within each protein level. Similarly, in Exp. 2 another 12 diets containing either 18.0 or 21.5% CP were fed to male broilers 29 to 48 days of age. In general, the Met + Cys requirement for optimum feed conversion was higher than for maximum growth. In both experiments, between 0.80% and 0.85% methionine + cystine optimized feed conversion. These dietary levels were valid for a 13.05 MJ ME/kg diet fed to broilers growing from 1.2 kg to 2.2 kg (Exp. 1), or for a 13.60 MJ ME/kg diet fed to broilers growing from 1.3 kg to 3.0 kg (Exp. 2). The Met + Cys requirement was not consistently affected by the dietary CP content in Exp. 1. In Exp. 2, increasing dietary CP from 18.0% to 21.5% tended to increase the Met + Cys requirement for optimum feed conversion. A dietary CP level of 18.0% to 18.7% supported performance and carcass fat deposition equal to diets containing 20.4% or 21.5% CP, respectively, when the sulfur amino acid content was adequate.

Aging↗

PubMed1998

Effect of different technical treatments of rapeseed on the feed value for broilers and laying hens.

The effect of different technical treatments of rapeseed on its feed value for broilers and laying hens was the object of the study. The technical treatments comprised different grinding procedures (whole seed, roller mill--coarse and fine adjustment, flake mill) resulting in different average particle sizes of the ground seed and thermal treatments of flaked seed (hydrothermal treatment, micronizer, jet sploder). Each thermal treatment was carried out at two temperatures. A marked increase in the digestibility of organic matter and of the AMEN content was observed as the average particle size of the seed was decreased to < or = 0.56 mm and was much more pronounced for the broilers. AMEN contents of 21.1 to 22 and 22.6 to 23 MJ/kg DM were observed at this particle sizes for broilers and hens, respectively. Thermal treatment of rapeseed improved the apparent crude fat digestibility slightly whereas the apparent crude protein digestibility tended to decrease especially at the higher temperatures. This resulted in inconsistent changes in the apparent digestibility of the organic matter and the AMEN content. Only the treatment with hot air (jet sploder) seemed to have preferential effects on the feed value for both broilers and hens. For the thermal treatments AMEN contents ranged from 18.8 to 21.9 and 19.0 to 24.3 MJ/Kg DM for broilers and hens, respectively.

Analysis of Variance↗

PubMed1999

Glycopeptide resistance in Enterococcus faecium from broilers and pigs following discontinued use of avoparcin.

The use of the glycopeptide growth promoter avoparcin was discontinued in Denmark in 1995 following concerns that vancomycin-resistant Enterococcus faecium occurring as a result of its use could be transferred to humans via food. The present study is an analysis of results obtained by the continuous surveillance of an antimicrobial resistance in Denmark (DANMAP) with the aim of determining the effect of the ban on the occurrence of glycopeptide resistance among E. faecium isolated from broilers and pigs. Among isolates from broilers, the proportion that were resistant to glycopeptides has shown a statistically high significant decline between the end of 1995 and the first half of 1998, whereas in pigs the ban appears to have no such effect. One possible explanation is that the broiler industry generally uses all in-all out production compared with continuous production in pig herds. Alternatively, the results indicate that the different outcomes may result from different co-selection patterns in pigs and broilers. In pigs, the antimicrobials most commonly used favored co-selection of glycopeptide resistant strains of E. faecium while in broilers the antimicrobials most widely used selected for glycopeptide-susceptible strains. The results show that intervention to reduce antimicrobial resistance may not always be effective and preventing resistance problems therefore becomes essential.

Animals↗

PubMed2001

In vitro starch digestion correlates well with rate and extent of starch digestion in broiler chickens.

Current feed evaluation systems for poultry are based on digested components (fat, protein and nitrogen-free extracts). Digestible starch is the most important energy source in broiler chicken feeds and is part of the nitrogen-free extract fraction. Digestible starch may be predicted using an in vitro method that mimics digestive processes in the gastrointestinal tract of broiler chickens. An experiment was designed to use this method for predicting site, rate and extent of starch digestion in broiler chickens. In vitro starch digestion was studied in 12 experimental diets differing in starch sources. These diets were also used in a digestibility trial with broiler chickens. Correlations between in vitro and in vivo starch digestion were calculated. Starch digestion after 2 h incubation correlated well with in vivo starch digestion in the first half of the small intestine (r = 0.94). A 4-h incubation period resulted in a good correlation between in vitro starch digestion and ileal starch digestion (r = 0.96). In vitro starch digestion rate (h(-1)) correlated well with in vivo starch digestion rate (r = 0.87). In vitro starch digestion of individual starch sources was additive. It appeared that legume seeds and waxy corn contained two starch fractions, which were digested at different rates. We conclude that starch digestion rate in broiler chickens is well predicted by the in vitro method.

Animal Feed↗