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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↗
PubMed1976

Manganese levels and the morphology of the epiphyseal plate in broilers with slipped tendons.

Manganese deficiency in chickens results in perosis and a higher incidence of slipped tendon. Perosis is associated with a disorganization of the epiphyseal growth plates and changes in the chemical composition of the cartilage matrix. Male broilers with slipped tendons were selected from a commercial broiler farm over a 9 week growing period. Their growth rates, epiphyseal cartilage histology and tissue manganese concentrations were examined and compared with (a) normal broilers from the same farm, and (b) similar broilers raised on control and manganese deficient diets. Field broilers with slipped tendons showed no evidence of abnormality in the histological appearance of the proximal tibial growth plate at any of the ages examined. The manganese content of liver and epiphyseal cartilage from field broilers showing slipped tendon was comparable with that present in tissue from normal broilers wither from the field or raised on a chemically defined diey supplemented with managese. The slightly retared growth rate seen in the field broilers was attributed to feeding problems associated with the lameness condition. These results provide conclusive evidence that slipped tendon in field broilers is not dur to a manganese deficiency in the tissues, nor does it appear to be associated with abnormal proliferation of the chondrocytes in the epiphyseal plate.

Animals↗
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↗
PubMed1975

The effect of heat exposure and bacterial endotoxin on plasma zinc concentration and the body temperature in the broiler.

The effect of heat exposure and bacterial endotoxins on plasma zinc levels and mean rectal temperature of 8 week old broilers and investigated. Broilers exposed for 2 hours to 35-35 degrees C. had higher (P less than 0.01) mean rectal temperatures (42.8 vs 41.7 degrees C.) than sham treated broilers maintained at 22-24 degrees C. Likewise, endotoxin (E. coli, 500 mug./kg) treated broilers also had mean rectal temperatures significantly higher (P less than 0.01, 42.4 vs 41.7 degrees C.) than sham treated broilers. Plasma zinc levels in the bacterial endotoxin treated broilers were lower (P less than 0.05) than in the sham treated (173 vs 220, and 219 mug/kg./100 ml. plasma, respectively). In contrast, the plasma zinc concentration was not significantly depressed in the broilers exposed to heat for 2 hours. In summary, either endotoxin or heat exposure resulted in increased body temperature, however only the response to endotoxin resulted in a significant depression of plasma zinc concentration.

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↗
PubMed1976

[Effect of noise on the physiological functions in fowl. 1. Effect of primary strong noise on the 11-OHKS level in broilers and leghorns].

The effects of first noises on broilers and white leghorns were tested by plasma levels on 11-hydroxycorticosteroid (11-OHKS). The noises were 100 dB, 60 to 8,00 Hz, and applied 30 minutss to one group of broilers, aged 14, 28, and 56 days, and to another group of broilers and white leghorns in adult age. The reactions were compared. Acoustic stimulation was followed by temporary activation of the hypothalamic pituitary-suprarenal system. The rise of the plasma glucocorticosteroid level in leghorns was three times as high as that in adult broilers, which was interpreted as a reflection of stronger organic stress. Reactions differed in intensity, depending on age as well. Plasma-11-OHKS levels went up by 32 per cent maximum in broilers aged 56 days or by 73 per cent in animals aged 14 days or 120 per cent in those aged 28 days. The above results seemed to support the conclusion that noises of the above quantity and quality represented stress on fowl.

11-Hydroxycorticosteroids↗
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↗
PubMed1975

[Studies on the use of wheat rich in crude protein in the feeding of broilers. 1. Experimental procedure, weight gains, food consumption and food efficiency].

A fattening trial was carried out with 8 groups of broilers each comprising 1225 birds. Within this trial tests were made to replace the protein feeds of newly hatched chicks over a period of up to 56 days of age, by wheat rich in crude protein. If wheat with a high crude protein content is fed supplementation with lysine and methionine will be necessary depending on the kind of protein feed used. No supplementation with amino acids is required if rations of fish meal + extracted soya bean meal are used despite their reduced content of these amino acids. The broilers consumed larger quantities of the wheat + extracted soya bean meal+fish meal ration than of the mixtures containing no fish meal. Food requirements per unit of weight gain were the same for the mixtures containing high-protein wheat and for the standard maize ration. The lowest food consumption per unit of weight gain was computed for the wheat + extracted soya bean meal diet supplemented with amino acids. The same quantities of lysine, thioamino acids and threonine were necessary for broilers receiving the wheat rations as for birds of the standard group. Protein feed may be saved by using high-protein wheat in the fattening of broilers. The rates of weight gain obtained with these rations are the same or even better than those achieved with rations of maize + fish meal+soya bean meal.

Animal Feed↗
PubMed1975

Body growth response to selection and crossbreeding in dwarf and normal broiler-type chickens.

A normal-bodied broiler population and one dwarfed by the dw sex-linked gene were each sub-divided into two lines. AGB (normal) and D2B (dwarf) were selected only for superior body weight at eight weeks of age. AGE (normal) and D2E (dwarf) were sublines in which prospective dams were selected for large egg weight while prospective sires were selected for eight-week body weight. Selection for large eight-week weight of both sexes in both dwarf and normal populations during each of three generations resulted in superior growth rate to that observed when the dams were selected for egg weight. When the selected dams were tested each generation for their ability to produce superior broiler crossbreds using a commercial broiler sire strain, AGE proved superior to AGB in the second and third generations while D2B and D2E dams produced crossbreds with similar broiler weights. Normal-bodied dams which produced crossbreds having superior growth to that of the dwarf dams in the first generation lost most of this superiority by the third generation in sons and the second generation in daughters. Reproductive fitness was superior within the dwarf lines as well as in their ability to produce more crossbred progeny.

Animals↗
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↗