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At least 19 recordsLinked to original sources
PubMed1975

[The occurrence of listeria encephalitis in cattle in a loose housing after the use of litter, infected with listeria bacteria, from a broiler farm. To what extent do listeria bacteria occur in the gut contents of broilers (author's transl)].

In a loose housing, four cows had to be slaughtered as an emergency measure within a few weeks because of symptoms of encephalitis. Listeria monocytogenes of type 4 b were isolated both from the brains of these cows and from the litter previously spread in the cow stables, which was obtained from a broiler farm. At the same time an investigation of the occurrence of Listeria bacteria in the faeces/gut contents of broilers was undertaken. From the contents of 2373 intestines, representing 0.1 per cent of about 2,300,000 broilers from 146 farms, Listeria monocytogenes were isolated in 4.1 per cent of the birds. The infection occurred on six broiler farms, two of them exhibited recidivation. Listeria monocytogenes of type 4 b were involved three times, type 1 was concerned on two farms, and one strain could not be typed.

Animals↗
PubMed1978

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↗
PubMed1978

Environmental temperature and choice feeding of the broiler.

1. Broilers were kept under environmental temperature regimens of 16, 21, 26 or 31 degrees and given, 22--57 d of age, either a complete diet or free-choice of whole wheat and a higher-protein food containing either 252 or 516 g crude protein (nitrogen x 6.25)/kg. 2. Broilers maintained at 16 and 21 degrees consumed food at a significantly higher rate than those kept at 26 degrees and the latter had a significantly higher food intake rate than broilers kept at 31 degrees, for each feeding treatment. Compared with 21 degrees the 57 d body-weight of broilers kept at 26 degrees and 31 degrees was significantly reduced. 3. When kept under the 16, 21, 26 and 31 degrees regimens, the amount of whole wheat in the food consumed by the broilers choice-fed with wheat and the 252 g crude protein/kg food was 56, 55, 48 and 46% respectively. The corresponding values for the broilers on the second choice-feeding treatment were 80, 76, 79 and 72%. 4. Except for a single instance the choice-fed broilers grew at a significantly slower rate than broilers given the complete diet.

Animals↗
PubMed2026

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↗
PubMed2026

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↗
PubMed1977

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↗
PubMed1978

[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↗
PubMed1978

[Effect of the temperature-humidity regimen on broiler resistance and on the efficacy of coccidiostats in experimental coccidial infection].

Experiments are carried out to elucidate the effect of the temperature and Moisture Regime on the resistance of broiler chickens to an experimental infection with coccidia and how far the prophylactic, anti-coccidial activity of coccidiostatics may be raised or reduced on this basis. During the experiment, prior to and after the infection of the chicken, investigations have been carried out on the morphological and biochemical composition of the blood, determining the contents of hemoglobin, total protein, vitamin A and vitamin E. It is established that the hematological and biochemical indices correlate with the course followed by the coccidiosis process and are related to the temperature and moisture regime in tending the broilers. If all other conditions are similar, the coccidiostatic activity of the Pankoksin Plus preparation is reduced both at lower temperatures and at higher degrees of infection with coccidia in broilers, and at a higher temperature and a lower relative, air moisture. The resistance of broiler chickens, grown at a temperature of 32 degrees C and air moisture of 70--75%, to coccidia infection is higher as compared with that of broiler chickens, kept at a higher temperature and a lower air moisture.

Age Factors↗
PubMed1976

Effect of fish and poultry byproduct meal on the small intestine and gizzard of broilers.

Commercial mixed-sex broiler chicks were used in two experiments to study the effects of various levels of Peruvian fish meal (PFM), menhaden fish meal (MFM) and poulty byproduct meal (PBPM) on the small intestine and gizzard. Intestinal and gizzard lesions were observed in broilers receiving finisher diets containing 7% or 12% PFM. The broilers receiving diets containing 12% MFM or 12% PBPM had intestinal and gizzard lesion scores that were not significantly different from those of the control broilers. The severity of intestinal lesions was greater than that of gizzard lesions in most groups. The causative agent in the PFM has not been identified.

Animal Feed↗
PubMed1979

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↗
PubMed1977

[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↗
PubMed1977

[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↗
PubMed1978

[Toxicity studies of Pharmachem's tylosin tartrate for broilers and turkeys].

Studied were the acute, subchronic, and chronic toxicity of the Pharmachim tylosin tartrate as well as the tolerance of chicken broilers and turkeys. The mean lethal dose of the antibiotic at subcutaneous application to 28-32 day-old broilers was 620 mg/kg; the oral dose was 1500 mg/kg. In the case of 42-45-day-old broilers these values were 740 and 5400 mg/kg. The LD50 at i/v infusion for 75-77-day-old ones was 48 mg/kg. Beside the age and route of introduction toxicity was found to depend on the initial biologic activity of tylosin tartrate. The subcutaneous injection of tylosin tartrate at the rate of 30 mg/kg for 20 days did not lead to changes in the appetite, behaviour, growth, and structure of viscera. A 42-day treatment at the same rate, however, resulted in slightly manifested and fully reversible dystrophic changes in the liver and kidneys. Higher doses (90 and 150 mg/kg) led to transient depression, stunting of growth, and a rise of the urea level and the activity of blood transaminases as well as to moderate destructive changes in the liver and kidneys. The stimulation of growth and the improvement of feed conversion (without deviations in the clinical and biochemical indices of the blood and the structure and development of the viscera in broilers) were recorded after the application of a water-soluble formula of tylosin tartrate for a period of 98 days offered via the drinking water in amounts equal to or exceeding 2 to 4 times the ED50. Turkeys' tolerance for the preparation was evaluated as very good so far as single i/m injective applications were concerned in doses exceeding 3, 5, and 10 times the average effective rates, no differences in this respect being noted with the comparative use of tylosin tartrate produced by the Elanco firm.

Animals↗
PubMed1976

Listeria-encefalitis in cows through litter from a broiler-farm.

In a loose-housed herd four cows are emergency-slaughtered, within some weeks, because of symptoms of encefalitis. From the brains of these cows, as well as from the litter, coming from broilers, that had been put in the cow-stables before, Listeria monocytogenes type 4b has been isolated. At the same time an investigation was made from faeces/intestinal contents of broilers. Out of the contents of 2.373 intestines, 1% of about 2.300.000 broilers ready for use, coming from 146 farms, 4.1% L.monocytogenes has been isolated. Six broiler farms are infected, at two farms it occurred even for the second time. Three times it concerned L.monocytogenes type 4b, two times type 1 and one strain could not be serotyped.

Animals↗
PubMed2026

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-&#x3b1;, NF-&#x3ba;B, IL-4, and TLR-1) was downregulated (P < 0.05). Microbiome analysis showed increased &#x3b1;-diversity (P < 0.05) and clear &#x3b2;-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 (|&#x3c1;| &#x2265; 0.50), revealing strong negative correlations between beneficial bacteria and inflammatory markers (&#x3c1; = -0.65 to -0.78) and positive associations for fungal taxa (&#x3c1; = 0.62-0.81). Serotonin was positively associated with microbial diversity (&#x3c1; = 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↗
PubMed1977

[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↗
PubMed1976

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

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

Animal Feed↗