Tenosynovitis in broilers and broiler breeder flocks.
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Animals↗
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Normal and pathologic skeletal development in broiler and leghorn chickens. A comparative investigation.
Skeletal development of broilers of two lines of the Hybro Compact strain was compared to the skeletal development of leghorns. Environment, management, and feeds were identical for comparable groups of broilers and leghorns. Half of the broilers (representing both lines) and half of the leghorns were given a high energy feed, while the other half of the birds of both breeds were given a low energy feed. No great difference in feed conversion between broilers and leghorns was found. The broilers consumed more feed and increased their body weight and volume of the tibia almost twice as fast as the leghorns. The difference in longitudinal growth of the tibia of the birds of the two breeds was much less evident. Locomotor disturbances (leg weakness) were common in the broilers, and in the majority of the cases the problems were caused by skeletal deformities. The leghorns were almost completely free of skeletal deformities and had no locomotor disturbances. Likewise, dyschondroplasia was not found in the leghorns, while it was common in the broilers. Most of the skeletal deformities in the broilers were explained as the result of mechanic-traumatic factors, acting on a rapidly remodeling skeleton, apparently of insufficient strength for the heavy body weight. Dyschondroplasia, on the other hand, was considered to be caused by a generalized factor governing growth. Basic histologic differences between broilers and leghorns already at an age of 7 days supported this theory. It was concluded that both leg deformities and dyschondroplasia in the broiler are man made problems, caused by genetic selection for characteristics of economic importance, without enough consideration to function and health of the animals.
Animal Feed↗
A Review on Heat Stress in Broiler Chickens: Mechanisms, Effects and Mitigation Strategies.
BACKGROUND: Heat stress (HS) is a major environmental challenge for broilers, particularly under rising global temperatures and high humidity. Broiler chickens are highly susceptible because of their rapid growth rate, high metabolic heat production, limited thermoregulatory capacity and genetic selection for fast growth. OBJECTIVE: This review aims to synthesise current evidence, evaluate the effectiveness of existing mitigation strategies, identify key knowledge gaps and provide future research directions to improve broiler resilience, welfare and productivity under increasingly HS conditions. METHODS: This review synthesised evidence published between 2010 and 2025 on the physiological, metabolic, intestinal, immunological and productive consequences of HS and evaluated mitigation strategies. RESULTS: The reviewed studies demonstrate that HS reduces feed intake by approximately 10%-30%, suppresses body weight gain and feed efficiency and increases mortality, with severity depending on temperature, humidity and broiler genotype. HS disrupts carbohydrate, protein and lipid metabolism; induces acid-base imbalance and oxidative stress; compromises intestinal barrier integrity; alters gut microbiota; suppresses immune function; and reduces meat quality. Nutritional interventions, including dietary electrolyte balance, antioxidants, vitamins, selenium, zinc, phytogenic compounds, probiotics, betaine and optimised feeding strategies, environmental management and genetic approaches, including naked-neck and frizzle genes, can partially alleviate these adverse effects. However, inconsistencies among studies persist because of differences in broiler strains, environmental conditions, dietary formulations and experimental protocols. CONCLUSION: HS substantially compromises broiler health, welfare, productivity and meat quality. Nutritional, environmental and genetic approaches can partially mitigate its adverse effects; however, further research is needed to improve broiler resilience under increasingly HS conditions.
Animals↗
Narasin used as a feed additive in conventional rearing of broilers can co-select for vancomycin-resistant Enterococcus faecium through the NarAB ionophore resistance mechanisms.
OBJECTIVES: To investigate the role of the NarAB resistance mechanism in the selection of vancomycin-resistant Enterococcus faecium (VREfm) and assess the impact of ionophore feed additives, particularly narasin, on the emergence of VREfm in broiler chickens. MATERIALS AND METHODS: Three isogenic E. faecium strains with different antimicrobial resistance determinants were created by mutagenesis and conjugation and used in a controlled animal experiment. Ross 308 broiler chickens were inoculated with either a rifampicin-resistant, a rifampicin- and vancomycin-resistant or a rifampicin-, vancomycin- and narasin-resistant strain and fed diets supplemented with selected ionophores. Bacterial populations were analysed on selective Slanetz and Bartley agar to determine the presence and selection of VREfm and other vancomycin-resistant species. Bacterial inoculation strains and isolates were whole genome sequenced for species identification and to identify genetic resistance mechanisms. RESULTS: Narasin was shown to select for VREfm in broilers, with NarAB being essential for co-selection. Intrinsically vancomycin-resistant Pediococcus acidilactici and Enterococcus gallinarum were identified as part of the broilers' vancomycin-resistant resident microbiota. Notably, among the P. acidilactici isolates that were susceptibility tested, strains resistant to both vancomycin and narasin were only found in broilers fed narasin, supporting that narasin promotes the growth of narasin-resistant populations. CONCLUSION: Narasin use in broiler feed can co-select for vancomycin-resistant bacteria, including VREfm, through the NarAB mechanism. These findings emphasize the concerns associated with the use of particular ionophores in poultry and suggest that vancomycin and narasin resistance may be more widespread in the broiler microbiota than previously recognized. Further research is needed to understand the implications for antimicrobial resistance and human health.
Animals↗
The effect of sex, dietary energy, meat protein, ascorbic acid and iron on broiler skin collagen.
Two studies were conducted to determine if variation of sex, dietary energy, meat protein, ascorbic acid or iron had any effect on collagen metabolism in broilers. In the first experiment day-old broiler type chicks were fed diets which contained 3190 or 3410 kcal. M.E./kg. of diet, 0 or 15% meat and bone meal and 0 or 1 g./kg. ascorbic acid. In the second experiment the day-old broiler chicks were fed diets which had 3190 or 3410 kcal. M.E./kg. of diet and 60 or 260 p.p.m. of iron. At 56 days of age the broilers were weighed, a representative number of birds killed from each group and skin samples collected. The skin samples were analyzed for the degree of collagen cross-linking and the total and insoluble collagen contents. An alteration of energy, meat protein, ascorbic acid or iron in the diet had no effect on collagen formation in the skin of broilers reared in cool environmental temperatures. Female broilers had a significantly higher percentage of insoluble collagen in the skin tissue but the level of total collagen and insoluble collagen was higher in the male birds.
Animals↗
[Incidence of Listeria monocytogenes in the intestinal contents of broilers on different farms (author's transl)].
The intestinal contents of 3,090 broilers, one day to five weeks of age, from 1,025 broiler houses, were examined for the presence of Listeria monocytogenes. L. monocytogenes was isolated in 243 cases, i.e. 23.7% of the broiler houses, 58.8% were of type 1, 35.5% of type 4b, 1.2% were of type 5 and 2.4% of the strains could not be typed. In spite of cleaning and disinfection after the chickens had been taken to the poultry slaughterhouse, reinfection occurred in the broiler houses in 16.9% of the cases; this occurred as many as eight times in succession. Various serotypes were isolated on one farm. Listeria organisms in the intestinal contents of healthy broilers do not affect the growth rate. Contaminated deep-litter (chips of white deal-wood) is a potential danger for man and animals, especially when used inn loose-housings on cattle farms.
Animals↗
The amino acid and energy requirements of broiler breeder hens.
Three trials, involving 1000 broiler breeder hens each, were conducted under rather uniform conditions in order to test the applicability of two models for calculating the amino acid requirements of broiler breeders, and to evaluate their energy requirements. The birds fed diets based on Model A (which assumes that all of the egg white and shell membrane proteins are synthesized during albumen formation and secretion at the expense of tissue proteins) produced at a rate greater than the planned target, whereas Model B (which assumes that only ovoglycoproteins and shell membranes are thus produced) supported a production close to the anticipated performance. This indicates the validity of Model B, developed for egg layers, to predict the requirements of the most limiting amino also for broiler breeder hens. The resulting practical diets contained considerably lower protein levels than customary. According to Model B, minimal amino acid requirements for broiler breeder hens producing a daily egg mass of 52.7 g. having a body weight of 3.5 kg and gaining weight at a rate of 4 g/day, calculated to be as follows (g/hen/day): methionine, .57; sulfur amino acids, .83; lysine, .76; arginine, 1.11; threonine, .72; valine, .92; isoleucine, .85; leucine, 1.25; tryptophane, .19; histidine,
Amino Acids↗
[Cross-infection during scalding and plucking of broiler chickens (author's transl)].
In two poultry-processing plants, experiments were carried out to detect cross-infection during scalding and plucking of broiler chickens. These trials showed that cross-infection was only detectable when experimental infection with the indicator micro-organism Escherichia coli K12 was applied externally to the broiler chickens. When infection was applied internally, only a small degree of transmission was observed. Indicator micro-organisms applied externally to broiler chickens prior to scalding and plucking, were present on the cooled product in larger numbers than those applied internally in the intestines of broilers. The number of carcasses which were positive after cooling was found to have decreased in poultry-processing plant B compared with the situation after plucking, whereas this number was not affected to any appreciable extent in processing plant A.
Animals↗
[Effect of the temperature-humidity regime during broiler raising on serum proteins and amino acids].
The study on the effect of the temperature and moisture regime on the serum proteins and amino acids in broiler chickens has revealed that under the conditions of relatively lower temperatures and higher relative moisture levels the total protein, the albumin, and the gamma-globulin fraction show higher contents. Noticeable are also some changes in the content of the bound amino acids (tyrosin, alfa- and beta-alanine, aspartic acid, and glycin) in the blood sera that are likewise depending on the temperature and moisture regime. The total amount of amino acids and the free forms of arginine and lysine are at higher levels in the broilers raised prior to the experiment at 32 degrees C and relative air humidity 70--75 per cent. With the remaining free and bound amino acids in the blood serum there are no differences in broilers raised at various temperature and moisture regimes. The body weight of broilers raised prior to the experiment at 32 degrees C and relative air humidity 70--75 per cent is higher, while the consumption of forage for kilogram weight gain is lower as compared to that with birds raised at higher temperature and lower relative humidity (35--45 and 50 per cent).
Amino Acids↗
Isoquinoline alkaloids enhance growth performance through multifaceted modulation of the bacterial-fungal microbiome, CAZyme profiles, gut health, and neuroendocrine function in broilers.
The bacterial-fungal microbiome and its carbohydrate-active enzyme (CAZyme) capacity play critical roles in regulating gut health and growth performance in broiler chickens. This study evaluated the effects of dietary isoquinoline alkaloids (IQ) on growth performance, gut microbiome composition, CAZyme profiles, and the microbiome-gut-neuroendocrine axis in broilers. A total of 400 Ross 308 (1-day-old) chicks were randomly assigned to either a Basal diet (CON) or IQ supplemented diet (IQ). Dietary IQ supplementation significantly increased final body weight and cumulative body weight gain (P < 0.0001) and improved feed conversion ratio (P < 0.05). Intestinal permeability was reduced (lower FITC-dextran; P < 0.05), accompanied by increased serotonin and serotonin-to-corticosterone ratio and decreased corticosterone (P < 0.05). Expression of inflammatory genes (TNF-α, NF-κB, IL-4, and TLR-1) was downregulated (P < 0.05). Microbiome analysis showed increased α-diversity (P < 0.05) and clear β-diversity separation (PERMANOVA, P < 0.001), with enrichment of beneficial bacteria (Akkermansia muciniphila, Lactobacillus salivarius, Turicibacter sanguinis, Bacillus subtilis) and suppression of fungal taxa (Aspergillus, Penicillium). CAZyme-related pathways involved in lignin and carbohydrate degradation were increased (P < 0.05). Microbial diversity was negatively correlated with inflammation and gut permeability, whereas network analysis identified 164 significant associations (|ρ| ≥ 0.50), revealing strong negative correlations between beneficial bacteria and inflammatory markers (ρ = -0.65 to -0.78) and positive associations for fungal taxa (ρ = 0.62-0.81). Serotonin was positively associated with microbial diversity (ρ = 0.63-0.70). In conclusion, IQ supplementation promotes a bacteria-dominant and metabolically active microbiome, reduces inflammation and intestinal permeability, and improves neuroendocrine balance, collectively enhancing gut health and growth performance in broiler chickens.
Bacteriome↗
[Use of wheat rich in protein for broiler feeding. 4. Nutrient and amino acid content of the consumable part].
After having finished a broiler-feeding experiment with wheat rich in protein under industry-like conditions eight by eight male and female animals from four groups were selected on their 56th day of life and experimentally cut up. Crude fat, crude protein, and amino acids contents were determined in the consumable parts (meat, gizzard, heart, liver, abdominal fat). The control group got the conventional broiler feed only. The protein fodder parts were reduced in the three experimental rations taking into account the covering of the needs of lysine and sulphur containing amino acids, by which two experimental rations were supplemented with 0.05% L-Lysine and 0.0% DL-methionine and 0.25% L-lysine and 0.15% DL-methionine respectively. It cound be established that except the lower dry matter content of the consumable parts of female broiler in the control group there were no significant differences through the influence of the rations. Furthermore no influence could be established of the high part of wheat rich in protein and the supplements of amino acids on the composition of the muscle protein.
Amino Acids↗
Preliminary investigation on the nutritive value of krill meal in the feed of broiler chickens and laying hens.
Krill meal was used as a protein feed in rations for broiler chickens and laying hens and its nutritional effectiveness was studied in comparison with conventional feed-stuffs of animal origin. In experiments with 650 broiler chickens from 1 to 28 and from 29 to 56 days to fattening krill meal was added to the standard feedmixture in lieu of fish meal, and dried skim-milk, and at higher levels also in lieu of soyabean oilmeal. In the experiment with 22 layer hens kept in individual cages 3% of the fish meal were substituted by 3% of krill meal. The performance of chickens fed on diets with krill meal was lower in comparison with analogical groups fed on fish meal. Higher levels of krill meal, exceeding 15 and 11% in the first and second period of feeding respectively, reduced the weight gains and feed intake of chickens. The fatty acid C14, C18 and C18:1 content of internal body fat was changed in chickens fed on higher levels of krill meal. In the experiment with hens krill meal decreased the feed efficiency, the pigmentation of egg yolks, however, was more intensive and the vitamin A content of yolks was increased in comparison with the control group. The results show that krill meal can be used as a partial substitute of fish meal in the feed of broilers and hens.
Amino Acids↗
Effect of dietary Fe to Cu ratios on hematological and growth responses of broiler chickens.
A total of 2,640 broiler strain cockerels were used in three experiments to determine the interrelationships between Fe and Cu requirements of 1- to 21-day old broiler chicks. In each experiment, a starch non-fat milk basal diet was fed to chicks maintained in battery brooders beginning at 1 day of age. Maximum hemoglobin levels and packed cell volumes (PCV) of 21-day old chicks were found by feeding 80 parts per million (ppm) of dietary Fe and 8 ppm of dietary Cu from 1 to 21 days of age. The heaviest 21-day old chicks were found by feeding 80 ppm dietary Fe. Variations were found among experiments in the copper requirement based on body weight. The Cu requirement ranged from 8 to 16 ppm as indicated by 21-day old chick weights. A 10:1 dietary Fe to Cu ratio with an Fe requirement of 80 ppm appeared to maximize hemoglobin levels and PCV's of 21-day old broiler chicks; whereas, a 5:1 dietary Fe to Cu ratio, rather than a 10:1, 15:1, or 20:1 ratio, maximized 21-day old chick weights. Iron requirements for hematological and growth responses are essentially the same; however, the copper requirement may be slightly different for the two criteria.
Animals↗
The control and prevention of necrotic enteritis in broilers with zinc bacitracin.
The effectiveness of zinc bacitracin in controlling andpreventing necrotic enteritis was tested by growing broilers in a facility where necrotic enteritis outbreaks had previously occurred. Broiler-crossed chicks were fed a commercial-type broiler diet containing 0 mg./kg., 33 mg./kg., or 55 mg./kg. of zinc bacitracin in the diet. Each treatment was replicated six times. Mortality, weight gain, feed conversion, and pigmentation were measured. The control group had 7.4% mortality due to necrotic enteritis as determined by necropsy of each bird upon death. Zinc bacitracin at 10 grams per ton had two mortalities, or 0.4% mortality due to necrotic enteritis. No mortality due to necrotic enteritis occurred with the higher levels of zinc bacitracin. The addition of zinc bacitracin significantly improved (P less than 0.01) the parameters of weight gain, feed conversion, and pigmentation.
Animals↗
The folacin requirements of broiler chicks and quail (Coturnix coturnix japonica).
Six experiments were conducted to investigate the effect of dietary composition on the folacin requirement of broiler chicks and to determine the folacin requirement of growing Japanese quail. The folacin requirement of both chicks and quail could not be determined when an isolated soybean protein based diet containing 0.44 mg. folacin per kilogram was used. Dietary composition affects folacin requirement of growing broiler chicks. Three values for the folacin requirement of growing broiler chicks were determined when three different basal diets were fed. With a low-glycine, casein based diet, growth was limited more by glycine than folic acid which improved growth only at 1.69 mg./kg. When 0.7% glycine was added to this casein diet, the folacin requirement was determined to be between 0.34 and 0.49 mg./kg. diet. However, with a casein-gelatin based diet, the folacin requirement was found to be between 0.12 and 0.27 mg./kg diet. Folacin deficiency in growing Japanese quail caused poor feathering, high mortality, leg weakness and cervical paralysis. A curly-toe system was observed in coturnix chicks fed low levels of folacin and might also be a consequence of folacin deficiency. The folacin requirement of growing Japanese quail was found to be 0.30 to 0.36 mg./kg. diet when a casein-gelatin based diet was fed.
Animals↗
Experimental infection of broiler and Leghorn chickens with virulent and avirulent isolates of hemorrhagic enteritis virus.
The effects of virulent and avirulent isolates of hemorrhagic enteritis virus were studied in Leghorn and broiler chickens. The viruses caused subclinical infections in both strains of birds. The avirulent isolate produced enlarged spleens, inclusion bodies, and antibody in all inoculated Leghorns. In broilers the avirulent virus produced infection in only half of the inoculated birds. Inclusion bodies were widely dispersed in the spleens of both types of birds. The virulent virus produced infection in all inoculated birds of both strains. Inclusion bodies were numerous in the spleens of Leghorn birds and were widely scattered in the spleens of broilers.
Adenoviridae Infections↗
[Contribution to the aetiology and epidemiology of botulism in broiler chickens (authors transl)].
The second outbreak of botulism in broiler chickens diagnosed in the Netherlands is reported. In this case, the source of botulinum toxin was positively located. Despite the fact that the owner had emphatically assured that all sick and dead broilers had been carefully removed, several carcasses of broilers, almost unrecognizable at first sight, were found to be present in the litter covering the floor, particularly at the rear of the fowl house. The concentration of toxin in the carcasses in the area surrounding this source of infection averaged well over 1,000,000 LD50 per gram of tissue. This is more than sufficient to account for the outbreak of botulism as the oral MLD of the strain of Cl. botulinum type C isolated in previous studied had been found to be well over 4,000,000 LD50 per kg of body weight for chickens, the oral MLD of the strain of Cl. botulinum type C isolated in the second outbreak being found to be 2,000,000 LD50 per kg. of body weight. In discussing the origin of the infection, attention is finally drawn to the possible relationship with the fact that botulism has become increasingly common among waterfowl in the Netherlands since 1970.
Animal Husbandry↗
[Rickets-like changes in broiler chickens (author's transl)].
A disease in broiler chickens associated with rickets-like symptoms observed on post-mortem examination is described. The disease is not caused by deficiencies in the feed. Treatment with vitamin D3, calcium and phosphorus has little if any effect. There is evidence to suggest a relationship with the origin of the broilers. It also is an established fact that the disease is related to the farm. Particularly those broilers will develop rickets-like symptoms, which were housed on litter previously used for chickens with the same disease. It probably is an infectious disease. Non-purulent inflammation of the glandular stomach is constantly observed in chickens showing rickets-like symptoms. This disease is transmissible to SPF chickens. It is not clear whether this is an accidental finding or typical of this clinical picture.
Animals↗