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At least 973 records · Page 54Linked to original sources

PubMed1990

Scanning and transmission electron microscopic observations of bacteria adhering to ileal epithelial cells in growing broiler and White Leghorn chickens.

1. Bacteria adhering to the ileal epithelial cells in broiler and White Leghorn (WL) chickens aged 1 to 60 d were observed with scanning (SEM) and transmission (TEM) electron microscopes. 2. In SEM observations, bacteria were not found on day 1 after hatching in either breed. In 10-d-old broilers many bacteria were observed around the apical area of villi. The number decreased with age and disappeared by 50 d. In WL chicks, the bacteria were first observed at 20 d. Numbers were much fewer than in broilers and none were seen after 30 d. 3. TEM investigations showed that bacteria had a cytoplasmic membrane, cell wall and nucleus but no nuclear membrane and organella, were compartmentalised and resembled Streptobacillus moniliformis. At the attachment zone to the epithelium, many mitochondria were observed in the epithelial cells; the bacterial membrane did not fuse to the epithelial cell membrane except at the apex of the attachment end where the bacterial membrane seemed to undergo lysis, suggesting a possibility that some bacterial components were transferred to the epithelial cells. 4. It is possible that the bacterial aid in the functioning of ileal epithelial cells. Possible functions are discussed in relation to the morphological features.

Animals↗

PubMed1990

Anti-nutritive activity of wheat pentosans in broiler diets.

1. To assess their possible anti-nutritive activity wheat pentosans were isolated from a milling by-product and added at graded levels to a sorghum-based broiler chicken diet. 2. A water-insoluble pentosan preparation (WIP, 720 g arabinoxylan/kg) caused a depression of apparent metabolisable energy (AME) of 1.63 MJ/kg DM at the highest level of inclusion (41.9 g/kg). Broilers maintained on this diet showed significant growth depression and a decrease in feed conversion efficiency. 3. A water-soluble pentosan preparation (WSP, 520 g arabinoxylan/kg) showed less anti-nutritive activity. 4. In a second experiment the AME of rice (pearled), maize, sorghum, wheat, triticale, barley and rye was determined. The AME values obtained were highly correlated (r = -0.98, P less than 0.001) with the summed levels of pentosans and beta-glucans found in the cereals. 5. It was concluded that the pentosans of wheat possess anti-nutritive activity when present in broiler diets and that similar polysaccharides may influence the nutritive value of other cereals.

Animals↗

PubMed1991

Aversiveness of motion and noise to broiler chickens.

1. The aversiveness of motion and noise to broiler chickens was examined using a passive avoidance technique. Birds were initially trained to peck a key a fixed number of times to obtain food. After training, food could still be obtained by key pecking, but feeding was immediately followed by 1 min exposure to noise or motion. Birds could delay or avoid exposure by delaying or avoiding key pecking, hence foregoing food. Reduced pecking rate was therefore taken as a measure of aversion. 2. In experiment 1, simultaneous motion and noise, but not noise alone, resulted in a significant decrease in pecking rate in comparison with baseline rates obtained after training. 3. In experiment 2 there was no significant difference in the pecking rates of 4 groups of broilers during training. However, after exposure to 1 of 4 types of motion, strongly significant differences in pecking rates were found between the groups. The mean latency to peak 3 times was significantly greater for birds exposed to gentle vibration, with a single jolt after 55 s, than for birds exposed to simple harmonic motion in either the horizontal or vertical plane. Birds exposed to circular motion in the horizontal plane had a significantly greater mean pecking latency than birds exposed to simple harmonic motion in the vertical plane. 4. Baseline latencies to keypeck in experiments 1 and 2 were longer than expected. In experiment 3 a direct comparison of baseline pecking was made between broilers and laying hens. The hens had significantly shorter pecking latencies.

Animals↗

PubMed1991

The response of broiler breeder hens to dietary lysine and methionine.

1. Broiler breeder hens were used in an experiment lasting 10 weeks (29 to 38 weeks of age) to measure the responses to dietary lysine and methionine, the main objective being to determine whether the coefficients of response to these amino acids were the same for broiler breeders and for laying pullets. 2. The hens were offered 150 g/d of one of 20 dietary treatments, 10 being lysine-limiting and 10 being methionine-limiting. The diets were mixed by diluting one of two concentrate (summit) mixes with a protein-free dilution mixture. The lysine-limiting summit diet was designed to supply approximately 1300 mg lysine/bird d, while the other supplied 520 mg methionine/bird d, when fed at 150 g/bird d. 3. Birds on the 5 lowest concentrations of both lysine and methionine did not consume the allotted amount of food, the amount decreasing, in a curvilinear fashion, to approximately 105 g/bird d. 4. The minimum egg weight recorded was 0.8 of the maximum, whereas the rate of lay of birds fed on the diets with the lowest amino acid concentrations was 0.2 of the maximum. 5. Using the Reading Model, the coefficients of response were calculated to be (for lysine) 16.88 E and 11.2 W, and for methionine, 7.03 E and 1.52 W, where E = egg output, g/bird d, and W = body mass, kg/bird. An average, individual, broiler breeder of 3 kg, producing 45 g of egg output per day, would need 793 mg of lysine and 321 mg of methionine daily. This intake of methionine is similar to that estimated by means of coefficients used for laying pullets, but the lysine requirement would be underestimated by 0.18 if the coefficients for laying pullets were used. 6. The coefficients for maintenance for both lysine and methionine, determined in this experiment, are considerably lower than values published previously, whilst the coefficients for egg output are, in both cases, higher. The resultant flock response curves therefore differed significantly from those in which the coefficients of response for for laying pullets were used.(ABSTRACT TRUNCATED AT 400 WORDS)

Animal Feed↗

PubMed1992

Differential leucocyte responses to various degrees of food restriction in broilers, turkeys and ducks.

1. White blood cell responses of broilers, turkeys and ducks were examined at regular intervals after being subjected to various degrees of food restriction. 2. Restricted-fed broilers showed increases in heterophil and basophil numbers, together with a corresponding decrease in lymphocytes. The heterophil/lymphocyte ratio was raised. There were no differences between broiler strains. 3. After only one week of feeding restricted diets, heterophils were significantly raised in selected and unselected 2-week-old ducks. At 21 weeks of age, those ducks receiving 50% of food required to achieve their ad libitum-fed body weight had raised heterophils. 4. Ducks receiving food to achieve 25% of ad libitum-fed birds produced a marked basophilia, but no heterophilia. 5. After two weeks of food restriction, turkeys responded with significant heterophil/lymphocyte ratios following two degrees of restricted feeding. 6. It was concluded that in some poultry, a heterophilia may be the response to mild to moderate stress but a basophilia may result after severely stressing birds.

Animals↗

PubMed1992

Early-life food restriction of broiler chickens. I. Methods of application, amino acid supplementation and the age at which restrictions should commence.

1. Three experiments were performed to examine practical methods of early-life food restrictions and to examine the influence of increased dietary lysine or methionine on bodyweight recovery during re-alimentation in broiler chickens. 2. Food intake of broiler chicks was restricted quantitatively or by dietary dilution at 3 ages and the birds slaughtered at 49 d of age. The success of each food restriction was measured in terms of bodyweight recovery and body fat content. 3. Discontinuous food restriction and restriction by dietary dilution produced similar effects to a previously established food restriction regime. Bodyweight recovery was complete and fat contents depressed. FCR was inconsistently affected. 4. Supplementation of the finisher diet with lysine and/or methionine produced no conclusive results when this diet was fed to broilers previously subjected to early-life food restriction.

Adipose Tissue↗

PubMed1992

Responses of broiler chickens to high-frequency and low-frequency fluorescent light.

1. The influence of the flicker frequency on physical activity and energy expenditure of broilers was studied using commercially available high-frequency (HF) and low-frequency (LF) fluorescent lamps in a 23L:1D lighting schedule. 2. Broilers were reared under and adapted to HF. They were alternately subjected to HF and LF during measurement of activity and energy expenditure. 3. In comparison with HF, LF inhibited activity (number and intensity of movements), but did not influence energy expenditure. 4. It was concluded that the 100 Hz flickering of low-frequency light is detected by broilers and has measurable behavioural effects upon them. 5. The results were discussed in relation to current knowledge of human and birds' critical flicker frequency and perception.

Animals↗

PubMed1992

Whole blood and plasma viscosity values in normal and ascitic broiler chickens.

1. Whole blood and plasma viscosity values in normal and ascitic broiler chickens were measured. 2. The mean blood viscosity value in ascitic broilers was greater than that of the controls. There was a small but significant difference in the opposite direction between plasma viscosity values of the respective groups of birds. 3. Although the haematocrit and arterial pressure index values in the ascitic birds were raised, there was a fall in the concentration of total plasma protein. 4. The data suggest that the raised viscosity in the ascitic birds was caused by a polycythemia and not by any influence of plasma protein. 5. The cumulative effect of these factors, such as raised blood viscosity values and larger deformed red cells flowing through constricted lung arterioles, may contribute to the pulmonary hypertension and ascites seen in some young commercial broilers.

Animals↗

PubMed1993

Growth and food intake responses to diets of different protein contents and a choice between diets containing two concentrations of protein in broiler and layer strains of chicken.

1. Food intake, protein intake and body weight gain were measured in male broiler and layer strains of chickens offered approximately isocaloric diets containing various concentrations of protein from 4 to 9 weeks of age. The carcases were analysed for protein, fat and ash. 2. In the first experiment 5 birds of each strain were given diets containing either 65, 115, 172, 225 or 280 g protein/kg fresh matter. The sixth group was given a choice between 65 and 280 g/kg. There was an approximately linear increase in protein deposition with dietary protein content up to 280 g/kg with broilers and 225 g/kg with layers. When a choice of diets was offered, birds of both strains grew at a rate not significantly different from that of birds on the diets with the lowest protein content which gave maximal growth given singly, by making an apparently appropriate choice from the two diets. 3. In the second experiment broilers were offered a choice of two diets in the following combinations: 65 and 115, 65 and 225, 115 and 225, 225 and 280 and 280, and 320 g/kg protein. They were able to differentiate successfully between two diets on the basis of their protein content and, where the two diets were on either side of the optimum, to change the proportions selected as they grew to match their changing requirement for dietary protein. When given two diets, both of which had protein contents lower than the single diets which gave maximal growth, birds ate predominantly from that closer to that optimal diet. When both diets had a higher protein content than the optimum birds ate mostly from that closer to optimum. 4. The results show that growing chickens can match their protein intake closely to their requirements when given a pair of diets that allows this; if both diets are on the same side of the optimum then the one closest to that required is predominantly chosen.

Animal Feed↗

PubMed1994

Xylanase in broiler diets with differences in characteristics and content of wheat.

1. Experiments were conducted to measure the effect of xylanase supplementation on the performance of broilers fed on wheat-based diets containing high and low extract viscosity wheat (experiment 1), baking and feeding quality wheat (experiment 2) and with variation in wheat content (experiment 3). 2. Xylanase supplementation improved food conversion ratios by 2.2-2.9% and body weight gain by 0.2-2.5%. This was independent of wheat characteristics but slightly dependent on the wheat content of the diet. These effects were related to a lowering of digesta viscosity. 3. Differences in extract viscosity of wheat were not reflected in broiler digesta viscosity. 4. Reduction of digesta viscosity resulted in only a slight improvement of litter score. Reduced intestinal viscosity decreased relative pancreas weight and to a lesser extent relative small intestinal weight. 5. Baking quality wheat Baldus gave better performance than the feed quality wheats Apollo and Slejpner. 6. It was concluded that xylanase supplementation of wheat-based diets invariably had a positive effect on broiler performance.

Analysis of Variance↗

PubMed1995

Influence of subclinical virus infections and other factors on broiler flock performance.

1. The influence of subclinical infections with infectious bursal disease virus, adenoviruses, REO viruses and chicken anaemia virus and of various production variables on broiler flock performance was investigated. 2. A significant effect could not be demonstrated of any of the viral infections either alone or in combination. 3. The production results were profoundly influenced by several other factors, that is, breed, diet, stock density and contents of whole wheat grain in the food. 4. The incidence of horizontally-transmitted subclinical chicken anaemia virus infection in Danish broilers has decreased significantly during the period 1988-89 to 1992-93, probably because of improved hygiene and management. The incidence of adeno- and REO virus infections did not change during the same period. 5. It is concluded that factors other than subclinical viral infections presently have an economic impact on performance observed in the Danish broiler production.

Adenoviridae Infections↗

PubMed1995

Use of ambroxol and bromhexine as mucolytics for enhanced diffusion of furaltadone into tracheobronchial secretions in broilers.

1. Ambroxol and bromhexine were evaluated as mucolytics and to enhance the passage of furaltadone into tracheobronchial secretions (TBS) in chronic complicated respiratory disease-affected broilers. 2. Viscosity of TBS was noticeably increased in the ambroxol-treated birds and only slightly increased in the bromhexine groups; however, the physical (nature) of TBS was superior in the ambroxol-treated broilers. 3. There was a clear increase in the passage of furaltadone into tracheobronchial secretions only in the ambroxol-treated birds. 4. Everyday use of ambroxol in broilers is discussed.

Ambroxol↗

PubMed1995

Effects of dietary sulphur-containing amino acids on performance and breast meat deposition of broiler chicks during the growing and finishing phases.

1. Two growth trials were performed to measure the effects of dietary methionine and cystine (SAA) on growth rate, food conversion efficiency and breast meat deposition in male broilers. 2. In experiment 1, broilers were grown on 6 experimental diets covering a range from 6.9 to 9.6 g SAA/kg. The diets were fed from 15 to 33 d of age. Similarly, in experiment 2, 6 diets containing 6.0 to 8.5 g SAA/kg were fed to finishing broilers 33 to 43 d of age. In each experiment 60 birds per treatment were processed, and carcase yield and breast meat percentage were determined. 3. Significant responses in weight gain, efficiency of food conversion and breast meat percentage were detected, which could be described well by exponential regression curves. Dietary SAA requirements to obtain maximum efficiency of food utilisation and maximum breast meat deposition were estimated to be about 9.0 g/kg from 15 to 33 d of age, and about 8.0 g/kg from 33 to 43 d of age. 4. Economic aspects were considered to calculate optimum SAA specifications from the results. In both trials, the dietary optimum of SAA was found to be higher for birds to be further processed than for birds to be marketed as whole carcases.

Animals↗

PubMed1996

Influence of different handling methods and crating periods on plasma corticosterone concentrations in broilers.

1. Experiments were conducted to determine whether different handling methods and crating periods differentially affect plasma corticosterone (CS) concentrations in 6 to 7-week-old broilers. 2. Broilers were subjected to 1 of 3 handling methods for 2 min: (i) 3 birds held in an inverted position in one hand (multiple inverted, MI), (ii) 1 bird held in an inverted position (single inverted, SI), or (iii) upright handling (U), which consisted of holding a bird gently with both hands in an upright position. 3. In experiment 1 birds were returned to their respective pens after handling and in experiment 2 they were crated for up to 4 h after the imposition of handling. In experiment 2 food deprived (FD) and fully fed (FF) uncrated birds were also sampled as controls. Blood samples were collected immediately after handling and at 1-h intervals after handling or handling and crating. 4. In experiment 1, MI and SI birds had higher CS concentrations than U birds. 5. In experiment 2, there were no significant differences in CS concentrations of crated birds despite the different handling treatments. FD birds had higher mean CS concentrations than FF birds, although not as high as those of crated birds. CS concentrations peaked at 3 h after crating. Birds showed predominantly resting behaviour after crating. 6. These results suggest that handling stress can be reduced in broilers by the use of upright handling. However, the methods of handling is not important in influencing CS concentrations if the birds are crated after handling, either because crating is a more potent stressor than handling or due to stressor additivity.

Abattoirs↗

PubMed1996

Acclimation effects on fed and fasted broiler thermobalance during thermoneutral and high ambient temperature exposure.

1. Two experiments were conducted to quantify heat stress (HS) acclimation effects on heat production (H), evaporative heat loss (E), sensible heat loss (S) and change in heat content (HC) of 24 food-deprived and precision fed broilers. 2. In experiment 1, heat stressed fasted HS acclimated birds (group 1) exhibited lower H (22.6 v. 25.5 kJ/kgW0.66 per h), E (7.5 v. 8.8 kJ/kgW0.66 per h), core body temperature (41.8 v. 42.4 C) and respiration rate (129 v. 160 breaths/min) than nonacclimated controls (group 2). 3. In contrast to the first experiment, precision fed HS acclimated birds (group 1) exhibited a higher H (29.3 v. 28.0 kJ/kgW0.66 per h) and E (10.5 v. 9.6 kJ/kgW0.66 per h) during HS and elevated H during thermoneutral periods than their non-acclimated counterparts (group 2). The elevated H became more pronounced with each successive HS exposure. 4. These results indicate that H increases when broilers are fed, that broilers preferentially dissipate heat as S when environmental conditions permit, and that food and/or energy consumption level markedly influences the bird's capacity to exhibit a HS acclimation response, and in fact has the ability to mask it.

Acclimatization↗

PubMed1996

Effect of dietary flax oil and hypobaric hypoxia on right ventricular hypertrophy and ascites in broiler chickens.

1. The effect of dietary flax oil on growth rate, blood haemoglobin content, mortality and incidence of pulmonary hypertension and ascites in broilers at ambient pressure and at reduced atmospheric pressure was examined. 2. Birds were housed either in hypobaric chambers simulating 1000, 1500 or 2200 m altitude or in pens at ambient atmospheric pressure and fed on diets containing 100 g/kg added fat as either an animal/vegetable (A/V) blend or flax oil. 3. Birds raised under hypobaric conditions had a decreased growth rate and increased mortality, blood haemoglobin content, and incidence of pulmonary hypertension and ascites compared to the groups at normal atmospheric pressure. 4. Broilers fed on the diet containing flax oil showed no difference in growth rate or blood haemoglobin content compared to birds fed on the A/V fat diet raised at the same altitude. 5. Inclusion of flax oil in the diet decreased mortality and the incidence of ascites at 2200 m and pulmonary hypertension at 1500 m. 6. Flax oil may be an effective method of reducing ascites and pulmonary hypertension in broilers without affecting performance.

Altitude↗

PubMed1996

Effects of food intake, soaking time, enzyme and cornflour addition on the digestibility of the diet and performance of broilers given wet food.

1. Four experiments were carried out to investigate the effects on growth, food conversion efficiency (FCE) and apparent diet digestibility, of wetting food before offering it to individually caged growing chickens. 2. Female broiler chicks (8/treatment) were given grower food ad libitum from 28-49 d of age either in the dry form or wetted with 2.0 kg water/kg air dry food, or wet food restricted to the same daily amount of dry matter as eaten by the dry-fed birds. Ad libitum feeding of the wet food significantly increased food intake and body weight gain, compared to dry feeding, while weight gains of birds with restricted feeding of wet food were intermediate. 3. Experiments 2 and 3 studied the effects of the time interval between mixing the food with water and offering it to the birds. When pre-soaking times of 0, 12 and 24 h were compared with dry food for male broilers (8/treatment) from 25 to 40 d all wet treatments increased body weight gains significantly, the best results coming from the zero soaking time, when DM digestibility was increased significantly from 677 to 714 g/kg. When restricted amounts of food were offered hourly for 8 h on each of 4 d, DM digestibility was significantly increased from 634 for dry food to 659 for that freshly mixed with water and 664 g/kg for that soaked for 1 h between mixing and offering. 4. In a factorial experiment with wet and dry food, either in the standard form or with added enzyme or 400 g/kg cornflour, there were significant positive effects on growth and FCE of broilers (7/treatment) attributable to enzyme and wetting, while cornflour significantly reduced growth. However, wet cornflour-diluted food gave better growth than dry standard food. Wetting significantly increased the apparent digestibility of dry matter and protein while dilution with cornflour significantly reduced protein digestibility. 5. These results confirm those previously presented in terms of improved growth and FCE with wet feeding and demonstrate a large improvement in the proportion of the food absorbed from the digestive tract, of similar magnitude to the improvement in FCE. They also show that it is not necessary to pre-soak food in order to attain the maximum effect.

Animals↗

PubMed1996

Studies on the toxic effects of crambe meal and two of its constituents, 1-cyano-2-hydroxy-3-butene (CHB) and epi-progoitrin, in broiler chick diets.

1. Studies were undertaken to determine a safe inclusion rate for crambe (Crambe abyssinica) meal in broiler chick diets, and to determine the mechanism for adverse effects by investigating its constituents; 1-cyano-2-hydroxy-3-butene (CHB) and 3-butenyl glucosinolate (epi-progoitrin, E-PG). 2. Crambe meals were prepared to differ in E-PG (19, 36 and 40 g/kg) and CHB contents (0.1, 0.7 and 1.9 g/kg), and with either active or inactive thioglucosidase. 3. Meals were fed to 7-d-old broiler chicks at 50 or 100 g/kg of the diet for 12 or 13 d. In separate studies, isolated E-PG or CHB were mixed into the diet or administered by gavage to 7-d-old broiler chicks in amounts equivalent to 50 or 100 g/kg crambe meal diets for 10 and 12 d, respectively. 4. Weight gain decreased (P < 0.05) in chicks fed on the high glucosinolate crambe diets or isolated E-PG. Food consumption decreased (P < 0.05) in chicks fed on the diet containing the high E-PG meal with active enzyme. 5. Mild liver lesions and increased serum aspartate aminotransferase were found in chicks fed on the diet containing the high glucosinolate meal with active enzyme. Other organs, including thyroids, were normal. 6. Commercially-processed crambe meal appeared safe at an inclusion rate of 50 or 100 g/kg diet, but could not be recommended at this point for long term feeding.

Alkenes↗