Showing papers in "British Poultry Science in 1999"

Effects of a xylanase on individual bird variation, starch digestion throughout the intestine, and ileal and caecal volatile fatty acid production in chickens fed wheat.

Abstract: 1. The effects of a xylanase on digesta viscosity and starch digestibility throughout the small intestine and volatile fatty acid production in the ileum and caeca were investigated in broilers fed on a low-metabolisable energy wheat diet. 2. The xylanase reduced (P<0.01) duodenal (2.9 vs. 1.7), jejunal (4.6 vs. 2.3) and ileal (14.0 vs. 3.9) digesta viscosities (mPas) and increased AME (P<0.01) of the wheat and starch digestibility (P<0.5) in the jejunum and ileum. Between-bird variability in ME and digestibility of starch was also reduced. 3. Enzyme supplementation reduced (P<0.05) fermentation in the ileum, but increased (P<0.05) it in the caeca. 4. The anti-nutritive effect of soluble non-starch polysaccharides (NSP) is related to their ability to increase digesta viscosity along the gut; this in turn causes changes in gut microflora and efficiency of nutrient utilisation by the chicken. Use of appropriate enzymes is an effective way of dealing with grains with high NSP content in poultry diets.

Effect of dietary high-and low-methylated citrus pectin on the activity of the ileal microflora and morphology of the small intestinal wall of broiler chicks

Abstract: 1. A study was conducted with broiler chicks to evaluate the effects of dietary high-methylated citrus pectin (HMC) or low-methylated citrus pectin (LMC) on the performance, nutrient digestibility, morphology of the small intestinal wall and ileal microbial activity. 2. Both pectin products were tested at a dietary content of 30 g/kg using a diet based on maize and soya flour. 3. Inclusion of HMC in the diet depressed weight gain and food utilization significantly. With a dietary addition of LMC there were only small decreases in weight gain and food utilisation. 4. Digestibility of dry matter, organic matter, crude fat, starch and amino acids, nitrogen retention and metabolisable energy value were reduced significantly when HMC was added to the diet. The addition of LMC to the diet reduced fat and ash digestibility and metabolisable energy value significantly. 5. Inclusion of LMC in the diet increased ileal viscosity marginally, whilst HMC had such an effect that the supernatant could not be extracted. Microbial activity in the ileum, particularly that of Enterococci, Bacteroidaceae, Clostridia and E. coli, was increased significantly with dietary addition of HMC. Inclusion of LMC in the diet did not greatly affect microbial activity as only the number of Clostridia was increased. 6. The addition of HMC to the diet markedly affected the morphology of the intestinal wall and significantly increased the number of goblet cells per 100 villus cells and the sucrase isomaltase activity was increased significantly. However, the morphology of the intestinal wall was hardly affected by LMC, whereas the number of goblet cells per 100 villi cells was significantly increased. 7. Results of the present study indicate that the inclusion of water-soluble pectins in diets of chicks changes ileal microbial activity and the morphology of the small intestinal wall. The magnitude of these changes depends on the degree of methylation of the pectins. © 1999 British Poultry Science Ltd.

Changes in feather condition in relation to feather pecking and aggressive behaviour in laying hens

Abstract: The aim of this experiment was to describe and examine the relationship between pecks received by individual birds and the feather and skin damage of those birds at different ages. The effect of group size was also studied. Laying hens were raised in floor pens in group sizes of 15, 30, 60 and 120 birds, each with 4 replicates. Behavioural observations were performed at the ages of 22, 27, 32 and 37 weeks. Detailed feather scoring was carried out at the ages of 18, 23, 28 and 33 weeks. Behavioural observations focused on the number of feather pecks (gentle and severe) and aggressive pecks received, and on the part of the body that was pecked. Scoring of feather and skin damage focused on the same 11 parts of the body. Increasing numbers of aggressive pecks received were associated with decreased body weight and increased feather damage at the ages of 27 and 32 weeks. The number of severe feather pecks received was significantly related with feather damage at all ages; however, no relation with gentle feather pecks received was found. Group size had a significant effect on feather condition, with large group sizes having most feather damage.

Prevalence of gastrointestinal helminths in different poultry production systems.

Abstract: A cross-sectional prevalence study of gastrointestinal helminths in Danish poultry production systems was conducted on 268 adult chickens selected at random from 16 farms in Denmark from October 1994 to October 1995. The trachea and the gastrointestinal tract of each bird was examined for the presence of helminths. In the free-range/organic systems the following helminths were found: Ascaridia galli (63.8%), Heterakis gallinarum (72.5%), Capillaria obsignata (53.6%), Capillaria anatis (31.9%) and Capillaria caudinflata (1.5%). In the deep-litter systems: A. galli (41.9%), H. gallinarum (19.4%) and C. obsignata (51.6%). In the battery cages: A. galli (5%) and Raillietina cesticillus or Choanotaenia infundibulum (3.3%). Exact identification of the cestodes was not possible because of missing scolexices. In the broiler/parent system: C. obsignata (1.6%), and finally for the backyard system: A. galli (37.5%) H. gallinarum (68.8%), C. obsignata (50.0%), C. anatis (56.3%) and C. caudinflata (6.3%). The results confirm the higher risk of helminth infections in free-range and backyard systems but prevalence may also be high in deep litter systems.

A comparison of ileal digesta and excreta analysis for the determination of amino acid digestibility in food ingredients for poultry.

Abstract: 1. The apparent ileal and excreta digestibilities of amino acids in 15 samples representing 12 food ingredients were determined using 5-week-old male broiler chickens. The ingredients included 3 samples of cereals (wheat, maize and sorghum), 6 samples of plant protein meals (soyabean meal, cottonseed meal, canola meal and sunflower meal) and 6 samples of animal protein meals (meat meal, meat-and-bone meal, feather meal and fish meal). 2. The test ingredients were incorporated as the sole source of dietary protein in assay diets. Each diet was offered ad libitum to 3 pens (4 birds/pen) from d 35 to d 42 post-hatching. Total collection of excreta was carried out during the last 4 d. All birds were killed on d 42 and the contents of the lower half of the ileum were collected. Apparent ileal and excreta amino acid digestibilities were calculated using acid-insoluble ash as the indigestible marker. 3. The influence of site of measurement was found to vary among food ingredients, among samples within an ingredient and among different amino acids within an ingredient. Ileal amino acid digestibility values were similar in some ingredients, but significantly lower or higher in others than the corresponding excreta values. 4. Average ileal and excreta amino acid digestibilities in sorghum and maize were similar, but significant differences were observed for individual amino acids. In contrast, ileal amino acid digestibility values were higher than the corresponding excreta digestibility values in wheat. 5. The average ileal and excreta digestibilites of amino acids in the 3 soyabean meal samples were similar although small, but significant differences were noted for individual amino acids. Site of measurement had no effect on the digestibility of amino acids in canola meal. Digestibilities of valine, isoleucine, phenylalanine, histidine, glutamic acid, alanine and tyrosine in sunflower meal and those of valine, methionine, isoleucine, leucine, lysine, glutamic acid and alanine in cottonseed meal were lower by excreta analysis. 6. Digestibilities in animal protein meals, with the exception of blood meal and fish meal, were consistently higher by excreta analysis. Ileal-excreta differences in individual amino acid digestibilities were more evident in feather meal, meat meal and meat-and-bone meal. 7. Threonine and valine were the indispensable amino acids that were more frequently influenced by the site of measurement. Of the dispensable amino acids, aspartic acid, serine, glutamic acid and alanine were the most affected. 8. Differences determined between ileal and excreta digestibilities in the present study clearly demonstrate that amino acid metabolism by hindgut microflora in chickens may be substantial and that digestibilities measured in the terminal ileum are more accurate measures of amino acid availability than those measured in the excreta.

Intracerebroventricular injection of orexins does not stimulate food intake in neonatal chicks

Abstract: 1. Recently, 2 novel neuropeptides were discovered, both derived from the same precursor by proteolytic processing, which bind and activate 2 closely related orphan G protein-coupled receptors, Named orexin-A and-B (Sakurai et al., 1998). Both stimulate food intake when administered centrally to rats. 2. Our aim was to elucidate whether central injection of mammalian orexin-A or-B stimulates food intake in the chick. 3. Under conditions of free access to food, orexin-A did not alter the food intake of chicks, but cumulative food intake was significantly suppressed by orexin-B. 4. The orexin-B was then administered to chicks deprived of food for 3 h to confirm its suppressive effect. No significant effect of orexin-B on food intake was detected. 5. Central injection of orexin-B did not modify food intake when appetite was stimulated by fasting. 6. Neither of these orexins appears to stimulate feeding in chicks.

Ideal amino acid profile and dietary lysine specification for broiler chickens of 20 to 40 days of age

Abstract: 1. The aim of the study was to determine the ideal ratio of the essential amino acids lysine (Lys), methionine (Met), threonine (Thr), tryptophan (Trp), arginine (Arg), valine (Val) and isoleucine (Ile) and to assess the required dietary lysine concentration for optimum performance in broiler chickens of 2 commercial strains from 20 to 40 d of age. 2. An identical basal diet was used throughout all experiments. It consisted mainly of maize and soyabean meal and contained 172 g crude protein and 13.2 MJ AMEN per kg. For each experiment, the basal diet was adequately supplemented with all essential amino acids except the one to be tested, which was supplemented in 6 graded concentrations in exchange for maize starch. One (Met, Trp, Arg, Val, Ile) or 2 (Lys, Thr) growth trials were conducted per amino acid tested and the response in weight gain, food: gain ratio, breast meat yield and abdominal fat were examined. 3. The ideal amino acid ratio relative to Lys (expressed as a percentage) was calculated to be 75% Met+Cys, 63% Thr, 19% Trp, 112% Arg, 71% Ile and 81% Val on a true faecal digestible basis when the data were subjected to broken-line regression analysis. From both lysine studies the concentration for optimum food: gain ratio was calculated, by exponential regression analysis, to be 11.5 g true faecal digestible lys per kg diet. © 1999, British Poultry Science Ltd.

Effect of rearing factors on the prevalence of floor eggs, cloacal cannibalism and feather pecking in commercial flocks of loose housed laying hens

Abstract: 1. Effects of rearing conditions on behavioural problems were investigated in a cohort study of commercial flocks of laying hens housed in 2 different loose housing systems. The sample population was 120 385 laying hens from 59 flocks of various hybrids at 21 different farms. 2. Logistic regression modelling was used to test the effects of selected factors on floor eggs, cloacal cannibalism and feather pecking. In addition to early access to perches or litter, models included hybrid, stocking density, group size, housing system, age at delivery, identical housing system at the rearing farm and at the production farm and, in models for floor eggs and cloacal cannibalism, nest area per hen. Odds ratios were calculated from the results of the models to allow risk assessment. 3. No significant correlations were found between the prevalence of floor eggs, cloacal cannibalism and feather pecking. 4. Access to perches from not later than the 4th week of age decreased the prevalence of floor eggs during the period from start-of-lay until 35 weeks of age, odds ratio 0-30 (P<0-001). Furthermore, early access to perches decreased the prevalence of cloacal cannibalism during the production period, odds ratio 0-46 (P=0.03). 5. No other factor had a significant effect in these models. Although it was not significant, early access to litter had a non-significant tendency to reduce the prevalence of feather pecking.

Spectral sensitivity of the domestic fowl (Gallus g. domesticus).

Abstract: 1. The spectral sensitivity of 7 broiler fowl was determined in a behavioural test. 2. Initially the birds were trained to receive a food reward by pecking at a clear, Perspex panel behind which was a light stimulus (circular, diameter=9 mm), originating from a tungsten-halogen lamp. Subsequently , they were trained to choose between 2 panels only 1 of which was lit; the assignation of light and dark on each panel was randomly ascribed between trials. The colour of the lit panel was determined by the wavelength of the light transmitted through one of 13 closely defined narrow bandwidth filters between 326

Effect of dietary zinc content and sources on the growth, body zinc deposition and retention, zinc excretion and immune response in chickens

Abstract: 1. In areas of intensive animal production heavy metals such as zinc (Zn), which is present at high concentrations in poultry excreta in relation to plant requirements, may be at the origin of soil phytotoxicity This study was conducted in order to determine the effect of decreasing dietary Zn content on growth, plasma, tibia and whole body Zn concentrations, immune function, enzyme activity, Zn body retention and Zn concentration in excreta in broilers. 2. Two experiments were carried out using 160 and 80 1-day-old chicks. Broilers received diets with increased Zn contents of 20 to 190 mg/kg. In experiment 1, two sources of zinc methionine were compared to zinc sulphate. 3. A dietary Zn concentration of 45 mg/kg was sufficient to obtain normal broiler performance at 21 d of age. 4. Tibia and plasma Zn concentrations increased linearly with Zn dietary content and reached a plateau at 75 mg/kg, whereas the whole body Zn was saturated when the dietary Zn content was 90 mg/kg. 5. Antibody titres in response to SRBC injection and plasma alkaline phosphatase activity were not affected by dietary zinc concentration. 6. When the dietary Zn content was decreased from 190 to 65 mg/kg, body Zn retention was increased from 8% to 20% and Zn concentration in broiler manure was reduced by 75%. 7. Zn sources had no effect on the parameters measured in this study. 8. A nutritional approach, that is by lowering dietary Zn supplementation may reduce the risks of phytotoxicity in the soil resulting from excessive Zn concentration in manure.

Performance and gastro-intestinal response of broiler chickens fed on cereal grain-based foods soaked in water

Abstract: 1. Two experiments were carried out to investigate the addition of 1 3 kg water per kg air-dry mash diets containing high proportions (600 to 700 g/kg) of ground cereal grains (wheat, barley or oats) on broiler performance and the structure and function of the gastro-intestinal tract. 2. Chicks at the age of 7 d were fed on the wheat-, barley- or oats-based diets in the dry or wet forms for 35 d. Food and water intakes were recorded daily while body weight was measured weekly. Two birds from each treatment were killed each week to measure gut size and the viscosity of gut contents. Tissue samples from various digestive segments were histo-morphologically examined to determine the thickness of tissue layers, size of tissue glands, villa heights, crypt depths and thickness of tunica muscularis. Crypt cell proliferation rate (CCPR) for each segment was also determined using a metaphase arrest technique. 3. The results from both experiments showed that wetting food significantly (P<0.05) increased food intake, total water intake and body weight gain of broiler chickens. The body weight gains of birds were proportional to their food intakes so that the efficiency of food utilisation was similar for all treatments. Dry matter retention of food tended to increase in birds given wet food from 7 to 21 d but not thereafter, compared to the dry-fed birds. Although water intake from the water bottle was significantly (P<0.05) reduced in birds given wet food, total water intakes from the water bottle plus that from food were significantly (P<0.05) higher in the wet-fed birds than in the dry-fed birds. The ratio of total water to dry food intake was, however, similar in both feeding regimens. 4. The fresh empty weight of the gut was increased by wet-feeding while its relative weight to body weight and the length of gut was not affected by dietary treatments. Significantly greater development of the tissue glands in the proventriculus and gizzard was observed in the birds given wet food; this was associated with the reduced thickness of the muscular layer of these segments. An increase in villus height was also observed in duodenum, small intestine, caeca and colon of birds given wet food, compared to those given dry food. CCPR was significantly (P<0.05) reduced by wet-feeding throughout the digestive tract. This was associated with a significant decrease in the mean viscosity of the gut contents and the concentration of volatile fatty acids (VFAs) in the caeca. 5. Wetting diets based on cereal grains caused a significant improvement in the performance of broiler chickens. The mechanism of the beneficial effects of wet feeding could be attributed to the decreased viscosity of gut contents; the greater development of the layer of villi in the digestive segments and the reduced CCPR in the crypts of the epithelium.

Tissue-specific changes in the activities of antioxidant enzymes during the development of the chicken embryo

Abstract: 1. Tissue-specific profiles of the expression of the antioxidant enzymes superoxide dismutase (SOD), glutathione peroxidase (GSH-Px) and catalase (CAT) and the concentrations of reduced glutathione (GSH) during the development of the chick embryo were investigated. 2. The liver, brain, yolk sac membrane (YSM), kidney, lung, heart and skeletal muscles were collected at the following days of embryo development: 10, 11, 13, 15, 17, 19, 21 and 22 (day-old chicks). 3. The different tissues of the embryo displayed distinct development strategies with regard to the acquisition of antioxidant capacity. In the liver the specific activity of SOD increased between days 10 and 11 of development, then significantly decreased up to day 15 and remained at the same value during the rest of the developmental period. GSH-Px specific activity increased through the time of development. CAT had 2 peaks of specific activity at day 10 of the development and in day-old chicks. 4. The brain was characterised by comparatively high SOD-specific activity especially during the last days of incubation. The specific activities of GSH-Px and CAT were low throughout development. 5. In the YSM maximal GSH-Px and CAT-specific activities were found on day 15 of incubation. In the kidney and heart GSH-Px-specific activity increased at hatching time. CAT-specific activity in the kidney increased just after hatching. 6. It is concluded that each tissue studied expressed a profile of antioxidant defence mechanisms to deal with oxidative stress at hatching time.

Genetic parameters of growth curve parameters in male and female chickens

Abstract: 1. Individual growth curves of 7143 chickens selected for the form of the growth curve were fitted using the Laird form of the Gompertz function, BWt=BWoxe(L/K)(1-e-20) where BWt is the body weight at age, BWo the estimated hatching weight, L the initial specific growth rate and K the maturation rate. 2. Line and sex effects were significant for each parameter of the growth curve. In males, L, BWo, age and body weight at inflection (TI and BWI) were higher whereas K was lower than in females. Lines selected for high adult body weight had higher BWo and BWI whereas lines selected for high juvenile body weight had larger estimates of L and lower estimates of TI. 3. Data from 38,474 animals were included in order to estimate the genetic parameters of growth curve parameters in males and females, considering them as sex-limited traits. Genetic parameters were estimated with REML (REstricted Maximum Likelihood) and an animal model. Maternal genetic effects were also included. 4. Heritabilities of the growth cu...

Organic matrix composition and ultrastructure of eggshell: a comparative study.

Abstract: 1. The avian eggshell is a biomineralised composite ceramic consisting of calcium carbonate embedded in an organic matrix. Matrix components are supposed to be involved in the control of mineralisation, crystallographic texture and biomechanical properties of eggshell. 2. The structure and eggshell matrix composition of various domesticated bird species were compared to gain insight into the universality of the eggshell mineralisation process. 3. The SDS-PAGE profiles of soluble eggshell matrix were specific within groups of birds (a: laying hen, breeder hen, quail, pheasant and possibly turkey; b: guinea fowl; c: duck and goose) but some of the protein bands were common to all groups. 4. Analogies between species were confirmed by Western blotting using hen protein antibodies. Ovocleidin-17 (OC-17) and ovalbumin were revealed in all species (except quail for OC-17). Lysozyme was present only in hen eggshell. Another egg white protein: ovotransferrin showed a positive signal in hens, turkey and quail. Osteopontin was observed in laying and breeder hens and quail. 5. Different proteoglycans were localised to discrete regions within the eggshell. Dermatan sulphate was observed within the matrix of the calcified shell of all species except quail which contained chondroitin-6-sulfate. Keratan sulphate was observed in mammillary bodies of breeder and laying hen, quail, pheasant and turkey while chondroitin sulphate was also present in guinea fowl and duck. 6. The general structural organisation of the different avian eggshells was similar but specific differences were observed in the ultrastructure of the mammillary layer. Species of the same taxonomic family could be grouped according to their structural analogies: breeder hen, turkey and pheasant resembled that of the domestic fowl. Guinea fowl was unique. Goose and duck were quite similar with large and confluent mammillary bodies. 7. Some matrix components are therefore common to eggshells of various species but more information is needed to relate differences in matrix composition between taxonomic groups with differences in ultrastructure.

Effect of sodium bentonite on the performance and blood variables of broiler chickens intoxicated with aflatoxins

Abstract: 1. This study was conducted to evaluate the protective effect of natural sodium bentonite (NaB) in the prevention of toxic effects of aflatoxins. Five hundred and twenty-eight 1-d-old Ross male broiler chickens were housed in pens (22 chickens per pen) for 42 d. There were 3 inclusion rates of NaB (0, 2.5, and 5 g/kg) and 2 of aflatoxins (0 and 3 mg/kg food). Each treatment had 4 replicates of 22 chickens. 2. All chickens treated with aflatoxin and without bentonite were adversely affected. NaB treatment at 5.0 g/kg improved body weights at 42 d of age by 31.3%, increased food intake by 23.8% and improved productive efficiency by 40.1%. Weights of liver, heart, pancreas and crop and biochemical variables were not affected by dietary NaB. However, serum phosphorous concentration was reduced by 30% compared with chickens that received aflatoxin. 3. NaB caused no adverse effects on chickens that did not receive aflatoxin. 4. It is concluded that NaB at pH 7.9 partially neutralises the effects of aflatoxins o...

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

Abstract: 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 mug/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 mug/kg chromium in an incubation medium influence their hepatocyte lipogenic capacity and adipocyte lipolysis, in vitro . 2. Dietary supplements of 1600 and 3200 mug/kg chromium in broiler diets significantly increased food consumption (P <0.05); 1600 mug/kg markedly improved weight gain (P <0.05); 1600 and 3200 mug/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 mug/...

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

Abstract: 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.

Effect of early-age thermal conditioning and food restriction on performance and thermotolerance of male broiler chickens

Abstract: 1.The effects of early-age thermal conditioning and food restriction on performance and thermotolerance were studied in male broiler chickens, in 2 trials. 2. Chickens were exposed to 36degree+/-1degreeC and 70% to 80% relative humidity (RH) for 24 h at the age of 5 d (thermal conditioning, TC), or to food restriction (FR) at the age of 7 to 14 d, or to both treatments (TC+FR), while a control group was reared under standard conditions. At the age of 42 d, chickens were thermally challenged by a heat stress of 35degree+/-1degreeC and 20% to 30% RH for 6 h. 3. In both experiments, weight gain of the TC chickens between the ages of 7 and 42 d was significantly higher than those of other treatments and was associated with higher food intake. 4. Early-age TC significantly increased body temperature (T ). Thermal challenge at the age of 42 d markedly increased T in all groups but that of the TC groups was the lowest. b 5. Mortality during thermal challenge was significantly lower in the treated chickens, excep...

Optimum inclusion of field peas, faba beans, chick peas and sweet lupins in poultry diets. II. Broiler experiments

Abstract: 1. Three experiments were undertaken to determine the optimum inclusion rates of field peas, faba beans, chick peas and sweet lupins in broiler starter and finisher diets in amounts up to 360 g/kg. 2. In experiment A chickens in cages grown to 21 d on diets with field peas and faba beans gave better growth rate and feed efficiency than those with sweet lupins and chick peas. Growth rate and Food conversion ratio (FCR) improved with increasing amounts of faba beans in the diet while for chick peas growth rate and FCR declined. Digesta viscosity and excreta stickiness scores were much higher on diets with sweet lupins. Steam pelleting improved growth rate and FCR on all diets. 3. In experiment B birds were in cages and grown from 21 to 42 d. There were no differences between grain legumes (when combined for all inclusions) for growth rate, food intake or FCR. Viscosity was again much higher on the sweet lupin-based diets while the pancreas was significantly enlarged on the diets with chick peas, as observed previously in chickens grown to 21 d. Steam pelleting of diets gave a consistent and positive response for weight gain and FCR. 4. Experiment C was carried out in pens each holding 60 birds under semi-commercial conditions and grown to 42 d on starter and finisher diets with the same grain legumes as used previously but each at 2 rates of inclusion similar to those in commercial practice. Field peas at 200 to 300 g/kg and chick peas at 150 to 220 g/kg gave inferior growth to faba beans (150 to 180 g/kg) and sweet lupins (120 g/kg). 5. The results of these experiments allowed tentative recommendations to be made to industry for inclusion rates of these cultivars of the 4 grain legumes. These were: field peas 300 g/kg; faba beans 200 g/kg, chick peas 100 g/kg and sweet lupins <100 g/kg. Wet droppings and high gut viscosity were serious problems with sweet lupins although these were not so obvious in experiment C.

Optimal dietary concentration of vitamin E for alleviating the effect of heat stress on egg production in laying hens

Abstract: 1. The effects of different dietary concentrations of vitamin E (alpha-tocopherol acetate) were investigated on laying hens exposed to chronic heat stress at 32 degrees C from 26 to 30 weeks of age. 2. Diets containing 5 dietary concentrations of vitamin E (a control diet containing 10 mg alpha-tocopherol/kg or this diet supplemented to contain 125, 250, 375 and 500 mg alpha-tocopherol/kg) were fed to 335 birds. Half of the birds received the supplemented diets for only 4 weeks before the heat stress period (short supplementation duration, SSD) and were fed on the control diet for a further 12 weeks. The remaining birds were fed on the supplemented diets throughout the experiment, 4 weeks before, 4 weeks during and 8 weeks after the heat stress period (long supplementation duration, LSD). 3. Egg production was significantly higher during (80-6 vs 68.9%, P<0.02) and after (75.3 vs 62.7%, P<0.02) the period of stress in the LSD group fed on the diet containing 250 mg vitamin E/kg compared with the group fed on the control diet. LSD birds given 375 and 500 mg vitamin E/kg also had higher egg production than control birds during heat stress but the differences failed to reach significance (74.6 vs 68.9% and 77.1 vs 68.9% respectively). In the SSD groups, mean egg production of the birds given the diets supplemented with 125 mg vitamin E/kg or more was significantly different from the control group after heat stress (70.3 vs 62.7%, P<0.05). Egg weight and food intake were similar in all the groups. 4. Plasma and liver vitamin E concentrations were proportional to the vitamin E intake before the stress period, dropped during heat stress in the SSD groups but were maintained at concentrations closer to those observed before heat stress in the LSD groups. 5. It is concluded that a dietary supplement of 250 mg vitamin E/kg provided before, during and after heat stress is optimum for alleviating, at least in part, the adverse effects of chronic heat stress in laying hens.

Incidence of pecking damage in growing bantams in relation to food form, group size, stocking density, dietary tryptophan concentration and dietary protein source

Abstract: 1. This paper reports 4 experiments with groups of 10 to 20 growing bantams in multi-unit brooders, which investigated effects of certain environmental and dietary factors on development of feather pecking damage to 6 weeks of age. Damage was assessed according to a subjective scoring system. 2. A test of food form (pellets, mash, mash diluted with 100 g/kg powdered cellulose) confirmed that pecking damage tends to be greater with pellets than with mash but there was no significant difference between the low damage scores associated with undiluted and diluted mash treatments. 3. A test of group size (10, 20 birds) and stocking density (744, 372, 186 cm2/bird) showed that variation in pecking damage was associated with group size density interactions. 4. A test of dietary supplementation with L-tryptophan (0, 10, 20 g/kg) showed suppression of pecking damage with the higher (20 g/kg) dose, compared with the control (0 g/kg) treatment. 5. A test of dietary protein source (plant, mainly animal, mainly semipu...

Response of broiler chickens to microbial phytase supplementation as influenced by dietary phytic acid and non-phytate phosphorus contents. I. Effects on bird performance and toe ash

Abstract: 1. Seven-day old male broilers (n=900) were fed on wheat-sorghum-soyabean meal-based diets containing 3 concentrations of phytic acid (10.4, 13.2 and 15.7 g/kg; equivalent to 2.9, 3.7 and 4.4 g/kg phytate phosphorus), 2 of non-phytate phosphorus (2.3 and 4.5 g/kg) and 3 of microbial phytase (Natuphos® 5000 L; 0, 400 and 800 FTU/kg) in a 19-d trial. The dietary phytic acid contents were manipulated by the inclusion of rice pollard. 2. Each dietary treatment was fed to 5 pens (10 birds/pen) from 7 to 25 d of age. Records of body weight, food intake and mortality were maintained. On d 25, all surviving birds were killed and toe samples were obtained for toe ash measurements. 3. Increasing dietary phytic acid negatively influenced body weight gain, food intake and food/gain. These adverse effects were partially overcome by the addition of microbial phytase. 4. Supplemental phytase caused improvements in weight gain and food efficiency of broilers but the magnitude of the responses was greater in low non-phyta...

Effect of light source and regimen on growing broilers.

Abstract: 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.

Analysis of risk factors for the occurrence of feather pecking in laying hen growers.

Abstract: 1. Potential risk factors for the occurrence of feather pecking in laying hen growers raised under commercial conditions were investigated on Swiss farms with more than 500 rearing places. On-farm interviews were conducted on a sample of 64 flocks which represented 42.6% of all farms concerned. 2. All variables considered were dichotomised and their univariate correlation with the occurrence of feather pecking was tested for significance at P<0 20 using chi 2 tests. Logistic regression with backward elimination was then used with the significant variables to identify the potentially most important factors influencing feather pecking. These variables included stocking density, light intensity, intensity of care, access to elevated perches, access to a roofed and littered outdoor area ('bad weather run'), time of access to the feeding facilities of the housing system, stocking density in the restricted area at the beginning of the rearing period, additional open feeding areas in the beginning and air qualit...

Laying hens in large flocks in a perchery system: influence of stocking density on location, use of resources and behaviour.

Abstract: 1. ISA Brown laying hens (3000) were housed in a perchery in 10 pens, each with 300 birds. The pens varied in size to produce 4 different stocking densities: 9.9 birds/m2 (n = 3), 13.5/m2 (n = 2), 16.0/m2 (n = 2) and 19.0/m2 (n = 3). Observations began at 20 weeks of age and continued until 69 weeks to establish the spatial distribution of the birds, usage of the different resources and the expression of behaviour. 2. Overall, birds spent most time on the perch frame (47%), litter area (23%), slatted floor (17%) and nestbox area (9%). 3. There was no effect of density on the proportion of birds observed on the slatted floor or on the elevated perches but as density increased the proportion on the littered area decreased. 4. Space usage was determined vertically, horizontally and longitudinally. Individual birds were seen to use about 80% of the pen volume available to them. This value was similar for all densities and showed that individuals did not have separate home ranges. 5. Fewer vertical movements were made within the main perch frame at the upper than at the lower levels but movements between the perches of the main frame and the nestbox rails were relatively frequent. This may help birds move up and down through the main frame. 6. Behaviours which decreased in incidence with crowding included moving, foraging and dust-bathing. Behaviours which increased with crowding included standing. Behaviours which were unaffected included resting, preening, prelaying behaviour, comfort behaviour and the minor behaviours. 7. The proportion of birds engaged in feeding and drinking was unaffected by density, except each time the chain feeders (which operated intermittently) ran more hens were seen feeding at the lower densities. This suggests that food delivery stimulated feeding behaviour; there may have been some restriction at the higher densities on birds feeding when and where they wanted. 8. Stocking density had no effect on the frequency of agonistic interactions: threats, lunges, comb/head pecks, chases and fights. 9. The incidence of damaging pecking was low and not density dependent. 10. Increasing density within the range investigated inhibited the expression of a number of behaviours and limited the use of specific resources: bird welfare at 19 birds/m2 may have been very slightly impaired.

Relationship between vitamin E content and susceptibility to lipid peroxidation in tissues of the newly hatched chick

Abstract: The effect of supplementing the diet of the parent hen with vitamin E on the vitamin E content of the yolk and of embryonic and neonatal tissues was evaluated and the effects of elevated tissue concentrations of vitamin E on peroxidation susceptibility was examined. 2. Laying hens (Ross 1 broiler-breeder strain) were maintained on diets containing either 147 (control diet) or 365 (high vitamin E diet) µ g vitamin E/g feed. 3. In the day-16 embryo, the concentrations of of vitamin E in the yolk sac membrane, liver, brain and lung were respectively 5· 0, 4· 3, 1· 7 and 5· 6 times greater for those derived from the hens on the high vitamin E diet compared with those from the control group. 4. In the day-old chick, the concentrations of vitamin E in the yolk sac membrane, liver, brain and lung were respectively 14· 8, 2· 8, 3· 0 and 5· 1 times greater for those derived from hens on the high vitamin E diet compared with those from the control group. 5. Homogenates of tissues from the day-old chick were incubated in the absence and presence of Fe 2+ in order to determine the extent of spontaneous and iron-stimulated peroxidation as measured by the genera- tion of thiobarbituric acid reacting substances. For the chicks derived from hens on the control diet, the brain was markedly more susceptible to both spontaneous and iron-stimulated peroxidation than were the other tissues. Tissues from the chicks derived from the hens on the high vitamin E diet exhibited significantly reduced susceptibilities to peroxidation. In particular, the susceptibility of the brain was reduced to the same level as that of the other tissues. 6. It is concluded that the high peroxidative susceptibility of the chick' s brain can be normalised by supplementation of the parent hen with vitamin E.

Optimum inclusion of field peas, faba beans, chick peas and sweet lupins in poultry diets. I. Chemical composition and layer experiments.

Abstract: 1. Experiments were undertaken to determine the chemical composition and apparent metabolisable energy (AME) of field peas, faba beans, sweet lupins and chick peas and the production of hens when each was included in nutritionally similar diets at 250 g/kg in 2 experiments. 2. Amino acid composition, crude protein and AME agreed well with previously published measurements. Detailed analysis of the non-starch polysaccharides (NSPs) showed that sweet lupins were much higher than the other grain legumes in the soluble NSPs and that the NSPs were particularly high in arabinose. The condensed tannin content was highest in field peas followed by faba beans. 3. In the 1st layer experiment over 40 weeks, hen-day egg production was lowest on the faba bean-based diet and egg weight and egg mass were also lowest. Relative viscosity of digesta in the small intestine of hens fed on the sweet lupin-based diet was highest, followed by that of hens fed on field peas. Enlargement of the pancreas was observed in hens consuming chick peas. 4. In experiment 2, in which only sweet lupins and faba beans were used, steam or cold pelleting showed few effects, nor did dehulling of faba beans but egg weight was lower when diets were steam pelleted. Daily food intake was 5.7 g/bird lower on the steam than cold pelleted diets and food conversion ratio tended to be improved (P=0.082). 5. It was concluded that field peas could support good production at 250 g/kg of layer diet. Although chick peas and sweet lupins supported good performance, there was concern about the increased weight of the pancreas and high gut viscosity respectively. Faba beans showed similar hen-d egg production in the 2nd experiment to that of sweet lupins but egg weight tended to be about 0.8 g lower than when on the sweet lupin-based diets.

Effect of clinoptilolite on performance of Japanese quail (Coturnix coturnix japonica) during experimental aflatoxicosis.

Abstract: 1. Clinoptilolite (CLI, a natural zeolite), incorporated into the diet at 50 g/kg, was evaluated for its ability to reduce the deleterious effects of 2 0 mg total aflatoxin (AF;83 06% AFB 1 , 12 98% AFB 2 , 2 84% AFG 1 and 1 12% AFG 2 )/kg diet on growing Japanese quail chicks from 10 to 45 d of age. A total of 40 Japanese quail chicks were divided into 4 treatment groups (control, AF, CLI, AF plus CLI) each consisting of 10 chicks. The performance of the birds was evaluated. 2. The AF treatment significantly decreased food consumption and body weight gain from the 3rd week onwards. The adverse effect of AF on food conversion ratio was also significant from week 4 of the experiment. 3. The addition of CLI to an AF-containing diet significantly reduced the deleterious effects of AF on food consumption, body weight gain and food conversion ratio. Food consumption was reduced by 14% in quail chicks consuming the AF diet without CLI, but by only 6% for quail chicks consuming the AF plus CLI diet. Similarly, o...

Effects of age and diet on the viscosity of intestinal contents in broiler chicks

Abstract: 1. A standard methodology was developed for the determination of the viscosity of digesta in broiler chickens. 2. The best variables considered for use (those which gave the most consistent results) were: digesta obtained from the foregut area (defined as the region from the pancreas to Meckel's diverticulum) using a minimum of 6 replicates and offering experimental diets for 5 d before slaughter at 25 d of age. 3. There was evidence that the viscosity of digesta obtained from the hindgut (defined as the region between Meckel's diverticulum and the ileo-caecal junction) was reduced the longer the birds were fed on one diet, suggesting possible dietary acclimatisation. Hindgut digesta viscosity from birds fed on a barley-based diet over a longer period was 10% to 30% less than that of birds fed for 5 d. 4. There was an apparent reduction in viscosity with age of bird up to 45 d of age, with hindgut digesta viscosity from birds fed on barley-based diets falling from 20.6 cps at 25 d to 9.8 cps at 45 d. 5. In an assessment of the procedure developed, the following digesta viscosities were obtained at 25 d: 3.1 cps (wheat-based diet, foregut), 19.8 cps (barley-based diet, foregut), 5.7 cps (wheat-based diet, hindgut), 22.8 cps (barley-based diet, hindgut).

Influence of dietary energy, supplemental fat and linoleic acid concentration on performance of laying hens at two ages.

Abstract: 1. The aim of this study was to investigate the influence of metabolisable energy (ME), supplemental fat (SFAT) and linoleic acid (LIN) content of the diet on the productive performance and weight of eggs and egg components of Isabrown hens of 22 or 74 weeks of age. 2. Six diets were formulated to contain the following concentrations of ME (MJ/kg), SFAT (g/kg) and LIN (g/kg), respectively: A) 11.8, 0 and 11.5; B) 11.8, 40 and 11.5; C) 11.8, 40 and 16.5; D) 11.2, 40 and 16.5; E) 11.2, 40 and 11.5; and F) 11.2, 0 and 11.5. Data were collected for 28 d and analysed using linear contrasts to test the effect of SFAT, LIN, ME and their interactions. 3. When the LIN content of the diets was maintained constant at 11.5 g/kg, an increase in the SFAT from 0 to 40 g/kg increased egg weight (63.8 vs 64.5 g; P<0.05), food intake (119 vs 124 g; P<0.01) and energy intake (1.36 vs. 1.42 MJ/d; P<0.01) and body weight change of the hens (-85 vs. 27 g; P<0.001). Supplemental fat also increased yolk (15.8 vs. 16.3 g; P<0.001) and albumen weight (40.8 vs. 42.3 g; P<0.01) but yolk to albumen ratio was not modified. 4. Egg and albumen weights were improved by SFAT in early but not in late producing hens. As a result, yolk to albumen ratio decreased in the younger hens, from 0.371 to 0.357, but increased in the older hens, from 0.408 to 0.415; P<0.01) with fat addition. 5. An increase in the LIN content of the diets from 11.5 to 16.5 g/kg did not modify any of the traits studied. 6. It was concluded that the LIN requirement of the hens for maximal productivity and weight of eggs is 11.5 g/kg or less. Supplemental fat increased the weight of eggs and albumen in the younger but not in older hens and the beneficial effect was independent of its LIN content.