System Of Broiler Chickens Research Articles

Impact of the Combination of Probiotics and Digital Poultry System on Behavior, Welfare Parameters, and Growth Performance in Broiler Chicken.

Recently, applied technology in the form of the combination of a probiotics and a digital poultry system, with the convergence of Information and Communications Technology and farm animals, has enabled a new strategy to overcome the livestock production crisis caused by climate change, while maintaining sustainable poultry farming in terms of care, feeding, and environmental management systems for poultry. The aim of this study was to investigate the biological mechanisms of animal behavioral welfare and production improvement using the combination of a probiotics and a digital poultry system in broiler chickens. A total of 400 one-day-old male broilers (ROSS 308) were randomly divided into four treatment groups, with five replicates each (20 birds/replicate pen) in a completely randomized design: control group with a conventional poultry system without probiotics (CON), conventional poultry system with 500 ppm of probiotics (CON500), digital poultry control system without probiotics (DPCS), and digital poultry system with 500 ppm of probiotics (DPS500). All experimental animals were reared for 35 days under the same standard environmental conditions. The experimental results indicated that the animal behavioral welfare, which includes drinking, eating, locomotion, grooming, and resting, in addition to foot pads, knee burns, plumage, and gait scores, as well as the growth performance of the broiler chickens, were improved by maintaining immune function and cecal microbiota balance via interaction between the combination of a probiotics and a digital poultry system. In conclusion, it was found that the combined system showed improved broiler growth performance and animal behavioral welfare. Thus, further studies of molecular biological mechanisms by the use of such a combined system to improve the nutritional composition and quality of chicken meats are recommended.

Evaluation of the effect of antibacterial and probiotic drugs on morphological changes in the body of broiler chickens

The results of a comparative histological study of the morphological reaction of parenchymal organs and organs of the immune system in broiler chickens using antibiotics and probiotics showed a positive effect of the probiotic drug on the body of broiler chickens of the experimental group. Two groups were formed according to the principle of analogues, a control and an experimental group of 35 heads each. Chickens of the control and experimental groups received the antibiotic enrofloxacin twice for 3 days up to 14 days of age according to the scheme of prevention of infectious diseases. Chickens of the experimental group received a feed additive (probiotic) based on microorganisms Bifidobacterium animalis from day 15 to 30. In a comparative study of the thymus of broiler chickens of the experimental group, the predominance of the cortical substance over the cerebral substance was noted in most of the lobules located on the periphery, and only in the merged lobules of the middle part of the thymus, the brain zone with a significant number of Ghassal bodies prevailed, a pseudoeosinophilic reaction was noted in the brain zone of the experimental chickens, as a result of the utilization of deposits and purification of the organ from the cells of the dead by the type of apoptosis. Histological studies of the spleen revealed activation of lymphoid follicles: in the chickens of the control group they were single on the preparation, and in the chickens of the experimental group there were three or more of them in one field of view. This indicates the activation of humoral immunity in chickens of the experimental group.In the study of the pancreas in chickens of the experimental group, a positive tendency was noted to increase the number and size of the islets of Langerhans, which regulate the function of carbohydrate metabolism.Analysis of the results of a comparative histological study of the morphological reaction of parenchymal organs and organs of the immune system showed that a number of reversible and irreversible pathological changes in organs were noted in the control group. Whereas in the experimental group where the probiotic was used, the organs corresponded to the physiological norm, which indicates a positive effect on the organs and on the body as a whole.

Evolvement of taste sensitivity and taste buds in chickens during selective breeding

Chickens have been reported to have a low taste bud count and thus low taste acuity. However, more recent studies indicate that the earlier reported count of chicken taste buds may have been significantly underestimated. To answer the question of whether the taste sensing system in broiler chickens evolved during the breeding selection over the past decades, we compared the taste sensitivity to bitter and taste buds between a meat-type control strain – the 1955 Athens Canadian Random Bred (ACRB), and a modern high-yielding broiler strain – the 2012 Cobb 500. The behavioral tests showed that the ACRB did not avoid bitter taste solutions of quinine hydrochloride (QHCl) at the examined concentrations (0.5, 1, 2, and 4 mM) (P > 0.05), while the Cobb 500 significantly avoided both the 2 mM and 4 mM QHCl solutions (P < 0.01). The labeling of chicken taste buds using the molecular marker Vimentin revealed that Cobb 500 chickens had a slightly higher number (P < 0.1), but lower density of taste bud clusters in the palate (P < 0.01) and the base of the oral cavity (P < 0.05) compared to the ACRB. We also found that a single amino acid change occurred in the bitter taste receptor T2R7. However, the functional analyses using HEK293T cells transiently expressing T2R7 revealed that the functions of T2R7 were comparable between the two strains. Taken together, our results demonstrated that taste sensitivities could be affected by the selection of the broiler chickens. The modern high-yielding broilers, which have massive feed intake and appetite, had a higher sensitivity to bitter taste stimuli than the meat-type chicken strain which was established decades ago. This evolvement of taste sensitivities may be associated with the alterations of an upper level of taste system, rather than the peripheral taste system, including distribution of taste buds and functions of taste receptors.

Effect of Fasting on the Spexin System in Broiler Chickens.

Simple SummaryThe regulation of physiological processes by biologically active substances such as peptides, proteins, or hormones is very important in the context of both the development of the basic sciences and their subsequent use in improving animal husbandry. One such substance is spexin (SPX), a recently discovered, very conservative peptide that has been shown in mammalian studies to be able to regulate food intake, as well as carbohydrate–lipid metabolism. Because there is no information on the role of SPX in the metabolism of birds in the literature, we first decided to determine whether the expression of the gene encoding this peptide is present in the various tissues of birds. A further object of the study was to determine whether the concentration of SPX in serum blood changes during the disturbance of the carbohydrate metabolism caused by starvation and whether these changes correlate with other metabolic parameters. These studies will help us fully understand the role of SPX in bird physiology, and this research should be further extended.Spexin (SPX) is a highly conservative peptide hormone containing 14 amino acids and was discovered in 2007 by bioinformatics methods. However, nothing is yet known about its role in the metabolism of birds, including broilers. The aim of this study was to investigate the effect of short-term fasting (2, 4, and 8 h) on the concentration of SPX in blood serum and the expression levels of the genes encoding this peptide (SPX1) and its receptors, GALR2 and GALR3, in the tissues involved in carbohydrate and lipid metabolism (muscles, adipose tissue, and liver). We also analyzed the mRNA expression of these genes in various chicken tissues. Moreover, we studied the correlation between the serum level of SPX and other metabolic parameters (insulin, glucagon, glucose, triglycerides, and cholesterol). Using RT-qPCR, we found that SPX1, GALR2, and GALR3 are expressed in all investigated tissues in broiler chicken. Moreover, using a commercially available radio-immunoassay, we noted an increase of the SPX level in blood serum after 4 and 8 h of fasting compared to nonfasted animals (p < 0.05). This increase was positively correlated with glucagon concentration (r = 0.341; p < 0.05) and negatively with glucose concentration (r = −0.484; p < 0.01). Additionally, we discovered that in the short term, food deprivation leads to the expression regulation of SPX1, GALR2, and GLAR3 in tissues associated with metabolism of carbohydrates and lipids. The obtained results indicate that SPX is involved in the regulation of metabolism in broiler chickens.

Efficiency of using Vitaferm in broiler poultry farming

The cultivation of poultry without the use of antibacterial drugs is a vital direction of modern production, since the entry of domestic poultry products to the foreign market involves their absence in raw materials of animal origin. As experience confirms, enrichment of feed rations with enzyme preparations and vitamins reduces the waste of young animals, significantly increases the feed absorption, and reduces their feed-gain relations per production unit. This allows enhancing the productivity of poultry farming while simultaneously improving the quality of resulting products. We have studied the effect of the new vitamin-enzyme complex Vitaferm on the broiler-chickens body against the background of the antibacterial drugs exclusion from their antiepizootic measures. Studies have shown a positive effect of Vitaferm on the poultry body which is manifested by an increase in average daily growth, livability enlargement and reduced feed-gain relations per production unit. These changes can be explained by the normalization of the digestive system of broiler-chickens with the Vitaferm use. It is known that antibiotics inhibit the body’s immune system and disturb the balance of intestinal microflora. Thus, the use of vitamin-enzyme complex Vitaferm with broiler-chicken feed at the rate of 15.0 g/kg, starting from the day-old up to 10 days, is proposed for the complete or partial exclusion of antibacterial drugs from the antiepizootic measures scheme.

The intensity of the processes of oxidative modification of proteins and the activity of enzymes of the antioxidant protection system of broiler chickens under the action of vitamins E and C

Chickens in the control group received a standard ration, the first experimental – ration with the addition of tocopherol acetate, the second experimental – ascorbic acid, and the third – a complex of these vitamins. On the basis of the conducted researches the influence of vitamin supplements on the indexes of oxidation intensity of lipid and protein structures was analyzed. The intensity of the processes of oxidative modification of proteins largely depends on the level of vitamins E and C in the ration of broiler chickens. Supplementation with vitamin C and with vitamin E resulted in an inhibitory influence on the content of OMP products, the level of which is largely regulated by the enzyme and non-enzymatic links of the antioxidant protection system. Searches have shown the stimulating influence of the addition of vitamins on the activity of antioxidant enzymes. In particular, SOD activity increased by 19 % on the 34th day, by 32 % on the 41st day, whereas glutathione peroxidase activity was 5.7 and 20.8 %, respectively, compared to the control chickens group. An increase in the activity of antioxidant enzymes occurred against the background of a decrease in the intensity of oxidation processes. At the same time, there was also an increase in the content of recovered glutathione in the blood of chickens of the second and third experimental groups at 34th and 41st days of age. Thereby, searches have shown that supplementing the ration with vitamins E and C with a positive influence on the organism's adaptive capacity and antioxidant potential, which is extremely important to ensure the metabolic homeostasis of chickens during critical periods of their cultivation.

Brain renin-angiotensin system in broiler chickens with cold-induced pulmonary hypertension

ABSTRACT1. The relative expression of angiotensinogen (AGT), renin, angiotensin-converting enzyme (ACE) and angiotensin II type 1 receptor (AT1R) was determined using quantitative real-time PCR on tissue from the brain (forebrain, midbrain and hindbrain) to investigate the effect of cold-induced pulmonary hypertension syndrome (PHS) in broilers aged 42 days. Brain angiotensin II (Ang II) and AT1R levels were measured using enzyme immunoassay.2. The right ventricle/total ventricles (RV/TV) ratio of the heart was increased in broilers exposed to cold stress (PHS group) at the end of the experiment.3. ACE and renin transcripts in three parts of the brain were significantly increased in the PHS group at 42 d of age compared to controls while AGT transcript was significantly increased only in the hindbrain of PHS birds. The amount of AT1R transcript did not differ between control and PHS groups.4. The amount of Ang II significantly decreased only in the midbrain of PHS birds compared with controls while the amounts of AT1R were not different between treatments in the three segments of the brain.5. It was concluded that brain gene expression of AGT (in the hindbrain), renin, and ACE was upregulated in broilers with PHS whereas Ang II and AT1R levels were not changed. These results provided evidence of diminished involvement of the renin-angiotensin system in the pathogenesis of chicken pulmonary hypertension.

Anti-inflammatory and antioxidant activities of probiotic powder containing Lactobacillus plantarum 1.2567 in necrotic enteritis model of broiler chickens

Lactobacillus is widely studied for prevention and treatment of intestinal diseases. The study was conducted to determine anti-inflammatory and antioxidative potential of Lactobacillus plantarum 1.2567 using necrotic enteritis (NES) model of broiler chickens caused by Clostridium perfringens. A total of 288 one-day-old broiler chickens were randomly categorized into 4 treatments: CON (basal diet), NES (CON + C. perfringens), LPT (NES + L. plantarum1.2567 powder with skim milk) and SKT (NES + skim milk). Results showed that L. plantarum 1.2567 increased average daily gain of the challenged broiler chickens (P< 0.05), reduced gross lesion scores of the small intestines and ameliorated ileum histopathology (P< 0.05), improved structure of enterocyte microvilli (P< 0.001), attenuated the nitric oxide concentration and myeloperoxidase activity (P< 0.05), reduced the chTNF-α and IL-1β levels and enhanced the activity of SOD and CAT(P< 0.05), and decreased MDA content (P< 0.05). But skim milk only improved structure of enterocyte microvilli of the challenged broiler chickens (P< 0.05). In conclusion, L. plantarum 1.2567 is a promising tool to control NES by regulating the intestinal mucosal immune response, and improving villi structure and antioxidant defense system in broiler chickens.

Descriptive Anatomy of Hepatic and Portal Veins with Special Reference to Biliary Duct System in Broiler Chickens (Gallus gallus domesticus): A Recent Illustration

ABSTRACT Chickens have a great participation in meat and egg production. The anatomical scientific data of poultry is important to support the recent researches either for illustrations in academic studies or clinically in diagnosis and treatment of some poultry nutritional diseases. The current investigation was performed on twenty broiler chickens of both sexes. The chickens were anaesthetized, slaughtered then the venous system was flushed with a normal saline to anatomically investigate the distribution of hepatic portal veins both intra and extrahepatic, as well as the hepatic venous and biliary duct systems. The fowl had two hepatic portal veins draining the gastrointestinal tract with its associated organs as spleen and pancreas. The left hepatic portal vein was small, restricted to a limited portion of left hepatic lobe and had been constituted by five main venous tributaries draining the proventriculus, gizzard and pylorus, while the right hepatic portal vein was the largest, receiving the proventriculosplenic, gastropancreaticoduodenal and common mesenteric veins then piercing the right hepatic lobe to be distributed in both hepatic segments through right and left divisions. The fowl has two hepatic portal veins differed in size and distribution. A characteristic imaginary trapezoid shape was formed by some tributaries draining the caudoventral part of the gizzard. There are three ileocecal veins; cranial, caudal and the ileocecal tributary of the cranial mesenteric vein. The wall of gall bladder and the common hepatoenteric duct was characterized by the presence of well-defined longitudinal folds or striations.

ERRATAS: Descriptive Anatomy of Hepatic and Portal Veins with Special Reference to Biliary Duct System in Broiler Chickens (Gallus gallus domesticus): A Recent Illustration

ERRATAS: Descriptive Anatomy of Hepatic and Portal Veins with Special Reference to Biliary Duct System in Broiler Chickens (Gallus gallus domesticus): A Recent Illustration

ПАТОГИСТОЛОГИЧЕСКОЕ ИССЛЕДОВАНИЕ ОРГАНОВ ДЫХАТЕЛЬНОЙ СИСТЕМЫ ЦЫПЛЯТ-БРОЙЛЕРОВ ПОСЛЕ АЭРОЗОЛЬНОЙ ДЕЗИНФЕКЦИИ ВОЗДУХА В ПРИСУТСТВИИ ПТИЦЫ

ПАТОГИСТОЛОГИЧЕСКОЕ ИССЛЕДОВАНИЕ ОРГАНОВ ДЫХАТЕЛЬНОЙ СИСТЕМЫ ЦЫПЛЯТ-БРОЙЛЕРОВ ПОСЛЕ АЭРОЗОЛЬНОЙ ДЕЗИНФЕКЦИИ ВОЗДУХА В ПРИСУТСТВИИ ПТИЦЫ

Age-dependent effects of short-term exposure of T-2 toxin or deoxynivalenol on lipid peroxidation and glutathione redox system in broiler chickens

Purpose of this study was to investigate the age-dependent, short-term effects of T-2 toxin (5.77 mg T-2 and 1.40 mg HT-2 toxin/kg feed) or deoxynivalenol (DON) (4.86 mg DON and 1.39 mg 15-acetyl-DON/kg feed) in one and three weeks old broiler chicken to observe the changes in parameters of lipid peroxidation, glutathione redox system, and expression of genes related to glutathione redox system in the first 24 h of mycotoxin exposure. Glutathione-redox system responsed to T-2 toxin exposure in both age groups for T-2 toxin in the first 8 h of exposure, while a reactivation was observed in the 3-week-old group after 20 h, although lipid peroxidation did not change significantly. DON did not alter these parameters, only at gene expression level. Gene expression of phospholipid hydroperoxide glutathione peroxidase (GPX4) showed minor, but significant, changes in both age- and mycotoxin exposure groups. Glutathione reductase (GSR) showed a dual response for the mycotoxin exposure, which was not consequent in either age groups, or treatments. Glutathione synthetase (GSS) showed a decreasing tendency in the younger animals while in the older group elevating tendency was observed as effect of both mycotoxins. Time, treatment and their combined effect also showed relation with the changes in the parameters.

Multi-trichothecene mycotoxin exposure activates glutathione-redox system in broiler chicken

Co-occurrence of mycotoxin contamination of feeds is a frequent problem, therefore the purpose of this study was to evaluate the combined effect of T-2 toxin and deoxynivalenol (DON) on lipid peroxidation, parameters and regulation of the glutathione redox system in broiler chickens in a sub-chronic (7 day) study. The applied doses were: low mix: 0.23 mg T-2 toxin and 4.96 mg DON/kg feed; medium mix: 1.21 mg T-2 toxin and 12.38 mg DON/kg feed; and high mix: 2.42 T-2 toxin and 24.86 mg DON/kg feed. Liver samples were taken on days 0, 1, 2, 3, and 7 of the feeding trial. Lipid peroxidation decreased significantly as compared to the control on days 3 and 7 as effect of low and high doses, which can be related to the activation of the antioxidant system, which is supported by the elevated glutathione peroxidase activity and reduced glutathione concentration as compared to the control on day 3 in the medium and high dose groups. Gene expression of glutathione peroxidase 4 (GPX4) elevated on day 1 in a dose dependent manner, and showed continuous elevation in the highest dose group thereafter. The results suggested that common exposure of T-2 toxin and DON induced oxidative stress in the liver of broiler chickens, which activated the enzymatic antioxidant system, and consequently decreased lipid peroxidation.

The development of the digestive system in broiler chickens at different levels of selenium into the mixed fodder

Scientific studies of foreign and domestic scientists convincingly proved that selenium is a vitally necessary trace element for farm animals and birds with a wide range of biological effects. It performs unique multifunctional functions in the body – structural, catalytic, regulatory, possesses antioxidant, anti-carcinogenic radioprotective, immunostimulant, antiviral, anti-mutagenic, anti-toxic and adaptogenic properties, participates in the formation of mechanisms that determine the reproductive function of animals and birds, affects osteogenesis, participates in the processes of growth and development. In the scientific and economic research the influence of additives of various doses of selenium into mixed fodder on the development of the digestive system in broiler chickens was studied. As a source of selenium, selenite sodium was used. The research was conducted in the production conditions on broiler chickens of the COOB 500 cross. The duration of the experiment corresponded to the period of growing the young for meat and was 42 days. It was established that the use of selenium in the composition of mixed fodder for broiler chickens at doses of 0.3; 0.4 and 0.5 mg/kg positively influenced the development of the digestive system in young, in particular, contributed to an increase in the mass (by 4.1–11.6%) and total length (1.3–3.5%) of the intestine in general, and its thin and thick parts in particular, as well as the mass of the muscular stomach (17.3–23.2%) and liver (3.6–10.0%). The best macromorphological parameters of the digestive system development were chicken broilers, which, during the entire period of growing, mixed fodder, were enriched with selenium at a rate of 0.3 mg/kg. Comparison of the live weight of broiler chickens of experimental groups with indicators of intestinal development, muscular stomach and liver allows us to assume that the digestive systems in them have been developed better and during the growing period they function more actively.

Effect of aquacitrate of micro elements on indices of nonspecific resistance and cellular immunity in chicken broilers

The article presents data on the influence of the complex of micro elements (Fe, Cu, Zn, Co, Mn) in the form of aquacitrate on the indices of non-specific and cellular immunity in chicken broilers. The poultry received a fodder, balanced by nutrients, according to its type, age and productivity. Control group of chickens were added standard mineral premix (SP) from inorganic compounds of bioelements. Broilers of experimental groups were given water with a complex mineral additive of aquacitrates. In particular, the chickens of the first experimental group – in the amount corresponding to their content in the standard premix (SP), and the 2nd, 3rd, 4th and 5th experimental groups – in the amount equal to 3/4, 1/2, 1/4 and 1/10 of the content of mineral elements in the standard premix. It was found that bactericidal and lysozyme activity of blood serum (BASB and LASB) were the highest in broiler chickens of the third and fourth experimental groups and exceeded the control values by 5.7 and 5.3%, respectively. In the bird of the second and fifth groups, the studied indicators were closer to the ones in control. However, in the chickens of the group D1, giving them the highest studied dose of aquacitrate of micor elements, the values of BASB and LASB tended to decrease. Concerning the level of CIC in serum, it was the highest in the chickens of the second, third and fourth groups, the lowest in the group D1. A similar pattern is also characteristic for phagocytic activity of pseudoiesinophils (PhA). The bite of half and even the quaternary amount of citrates of micro elements, compared with the amount of bioelements in inorganic form, provided an increase, compared to control, of PhA. At such a dose of micro elements in the nanoform in the blood of broilers, the number of T-total and T-active lymphocytes increased, including T-heeler cells and decreased the relative number of T-suppressors. The bird of the first experimental group was characterized by a decrease in the percentage of T-heeler against the background of a slight increase of T-suppressors. Thus, the results of studies of indices of nonspecific and cellular immunity suggest that micor elements in the nanodisperse form, due to better bioavailability and high bioactivity, have a positive effect on the formation and development of the immune system in broiler chickens at a dose corresponding to 25 and 50%, from recommended quantity of biometals in the standard premix.

Upregulation of genes encoding digestive enzymes and nutrient transporters in the digestive system of broiler chickens by dietary supplementation of fiber and inclusion of coarse particle size corn

BackgroundMeasures to improve bird performance have been sought due to the imminent phase out of in-feed antibiotics in poultry and continued demand for higher poultry feeding efficiency. Increasing grain particle size and dietary fibre may improve gizzard function, digestive efficiency and nutrient absorption. This study was conducted to evaluate the effect increased particle size of corn and inclusion of sugarcane bagasse (SB) on mRNA expression of genes encoding digestive enzymes and nutrient transporters in broilers.ResultsA total of 336 day-old Ross 308 males were assigned in a 2 × 2 factorial arrangement of treatments with corn particle size - coarse 3576 μm or fine 1113 μm geometric mean diameter, and SB - 0 or 2% inclusion. Feed conversion ratio (FCR), weight gain and feed intake were measured from d 0–10 and d 10–24. The relative gizzard weight and mRNA expression of genes encoding digestive enzymes and intestinal nutrient transporters were measured on d 24. During d 10–24, a particle size × SB interaction was observed for FCR (P < 0.01), where birds fed coarsely ground corn (CC) with 2% SB had lower FCR than those fed CC without SB. A particle size × SB interaction was observed for both expression of pepsinogen A and C (P < 0.01) which were negatively correlated with FCR on d 24. Addition of 2% SB upregulated pepsinogen A and C only in CC fed birds. Further, 2% SB also upregulated pancreatic amylase (AMY2A) and intestinal cationic amino acid transporter-1 (CAT1). Inclusion of dietary CC upregulated duodenal amino peptidase N (APN), jejunal alanine, serine, cysteine and threonine transporter-1 (ASCT1), and ileal peptide transporter-2 (PepT2).ConclusionThese results suggest that both SB and coarse particle size modulate expression of genes encoding important digestive enzymes and nutrient transporters and thus are directly related to bird performance. These findings provide insights into the combination effects of dietary fiber and particle size in the future management of broiler feeding.

The Effect of Oral Administration of Levamisole on Performance and Related Parameters with Immune System in Broiler Chickens

The Effect of Oral Administration of Levamisole on Performance and Related Parameters with Immune System in Broiler Chickens

The Effect of Different Levels of Levamisole Drug on Performance and Related Parameters with Immune System in Broiler Chickens

The Effect of Different Levels of Levamisole Drug on Performance and Related Parameters with Immune System in Broiler Chickens

Nutritional aspects related to non-infectious diseases in locomotor system of broilers

The maximum efficiency requirements in poultry include management, health, nutrition and environment. However, the interaction of these factors is not always met, generating malfunctions in the metabolism, physiology and anatomy. The incidence of leg weakness in rapidly growing birds has become a major concern in the poultry sector, not only due to poor performance and condemnation in processing plants, but also to compromised animal welfare. This article aims at reviewing the main nutrition-based diseases affecting the locomotor system of broiler chickens.

Effect of Low Environmental Temperature on Performance and Blood System in Broiler Chickens (Gallus domesticus)

The aim of this study was to assess the effect of low environmental temperature on growth, feed conversion, performance and selected biochemical and haematological indicators in broiler chickens. The decrease in air temperature since the 22nd day of growth influenced significantly (p &lt; 0.05) the level of total proteins, uric acid, phosphorus (in female broiler chickens), glucose (in male broiler chickens), haemoglobin (in female broiler chickens) and liver weight (in male broiler chickens). The temperature influenced significantly (p &lt; 0.01) the level of triiodothyronine, haemoglobin (in male broiler chickens), haematocrit, abdominal fat content (in male broiler chickens), and heart weight too. The results have clearly confirmed that during growth, the decrease in environmental temperature (cold stress) negatively influenced some indices of performance and blood system in broiler chickens.