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The global warming and climatic changes is particularly deleterious to tropical agriculture in general and to the animal genetic resources in particular, impairing initiatives for their sustainable management. In order to contribute to the mitigation of the effects of climate changes on agriculture, this study was carried out to determine the effect of hyperthermia on the haematology and physiological parameters of the local chicken and a commercial broiler breed in tropical environment. For this purpose, pens of local and exotic chicks after the starter phase were conducted separately at 25 and 35°C. In the two genetic types, the effect of heat stress caused an increase of 525.43% of leukocytes in exotic chickens and of 1778.43% in local chickens. The same was observed for the monocytes in local chickens (227.22%). The mean globular volume, mean cellular haemoglobin and mean cellular concentration in haemoglobin were reduced in the local chicken, by -10.23, -22.87 and -14.07% respectively, but the values of these parameters were increased in exotic chickens by 179.54, 214.09 and 12.36%. The results of heat tolerance indexes suggested that with age the local chicken easily overcome heat stress, while the exotic chicken become increasingly vulnerable. These results have been confirmed by the high mortality rate observed in the commercial stock under heat stress, while there was no mortality among the local chickens. Key words: Adaptability; blood; chicken; hyperthermia; physiology
International Journal of Advanced Research (IJAR)
EFFECT OF HEAT STRESS ON PHYSIOLOGICAL AND SOME BLOOD PARAMETERS OF THREE LOCAL CHICKEN AND A BROILER GENOTYPES REASED IN HUMID SUBTROPICAL CLIMATE OF COTE DIVOIRE.2019 •
The present study was carried out for evaluating the response of chickens from four genotypes such as naked-neck, frizzle, normal feather and broiler subject to heat stress in order to show the best bird genotype. Thus, for achieving that purpose, the study was conducted in a private farm located in the locality of Ti?pl?, precisely in the center of C?te d\\\\\\\'Ivoire in the department of Bouak?. The experimental chickens were selected randomly from a group of chickens genotypes identified and were exposed to ambient temperature and warm temperature. Results showed that temperature had a significant effect onto breath rates of broiler and frizzle genotypes, but it had no significant effect on that of the normal and naked-neck genotypes. Moreover,temperature influences significantly the white blood cell and hemoglobin rates of all genotypes (p <0.05) which increase according temperature level. Likewise, a significant effect of temperature onto the MCHC rates of all bird genotypes was observed (p ˂0.05).This rate increases with increasing of heat stress for all genotypes. However, there is no significant effect of temperature on the calcium and phosphorus rates of all genotypes (p˃0.05). Otherwise, temperature does not have any effect on magnesium rate of the naked-neck and broiler genotypes, (p> 0.05), while it influences significantly the magnesium rates of normal feathered birds (p ˂0.05). The results of this work indicated therefore that there was a relationship between heat resistance or tolerance and acclimation of birds which it is in favor to indigenous chicken genotype precisely the naked-neck genotype.
This study was carried out to determine the effect of hyperthermia on growth parameters of the local chicken and exotic broiler breed in tropical environment at 25 and 35°C. The chickens were raised at 25°C consumed more food than those raised under hyperthermia. The consumption reduction in local chickens under thermal stress varies from - 2.39 to -7.90%. In hyperthermia, water consumption increased in exotic chicken (4.99 to 7.04%) but, decreased (7.50%) in local chicken. The weight loss at 8th weeks in exotic chickens varies from -24 to -29%, while the local chicken under the same challenging stress increased live weight by 10 to 34%. Hyperthermia resulted in a reduction of the weight gain of -3.09% in local chicken and -14.56% in exotic chicken. The consumption index increased by 57.72% and 60.67% respectively in local chicken and exotic strain respectively. The carcass yield decreased by 25.79 and 15.01% respectively in exotic and local birds respectively. In the two genetic types, the induction of heat stress caused a decline in the proportion of the pancreas by 37.83% in the local chicken and by 25% in the exotic strain. The proportions of other organs declined in local chicken (-22.34% to -36.36%) and increased in exotic chickens (10.33 to 24.59%). These results showed that local chicken have better adaptability to heat stress than exotic chicken. Key words: Adaptability; chicken; hyperthermia; productivity
The poultry sector produces chicken meat and eggs, which are the most significant protein sources among livestock foods. The industry is dealing with the effects of climate change, which is creating heat stress and negatively influencing poultry performance and well-being. Heat stress has been the most significant climatic stress confronting the worldwide poultry business, with birds having just a small temperature range when stressed. The purpose of this paper is to determine the effect of heat stress on the performance and well-being of hens. The study examined the research articles of numerous researchers and discovered that high temperature influences poultry performance, nutrition, and health. High temperature decreases feed efficiency, body weight, feed intake, and egg production while increasing the proportion of mortality and the incidence of pathological injuries in poultry fields, which generate major material losses.
Pertanika Journal of Tropical Agricultural Science
TROPICAL AGRICULTURAL SCIENCE Thermotolerance Acquisition in Broiler Chickens through Early Feed Restriction: Response to Acute Heat StressThe objective of this work was to assess the level of stress sensitivity of three genotypes of chickens differing in body weight. A total of 62 birds of the 3 genotypes (21 local chicken, 20 commercial naked neck and 21 fully feathered hybrid chicken were reared in confinement together, under the same conditions. Body parameters and body temperature (BT) at 30 weeks of age was recorded for each genotype 3 days. All other body parameter traits were differed significantly among the genotypes. Commercial naked neck and fully feathered had better in almost all the traits. However, at day1, BT1 were 41.435 ?C, 41.709 ?C and 41.915 ?C respectively for local chickens, naked necks and fully feathered hybrids under 37.1?C of ambient temperature and relative humidity of 46 %.. At day 2, the BT2 were 41.271 ?C, 41.637 ?C and 41.825 ?C respectively for local chickens, the naked necks and the fully feathered hybrids, under 36 ?C of ambient temperature and relative humidity of 40 %. At day 3, the BT3 were 41.369 ?C, 41.585 ?C and 41.784 ?C respectively, under 35.2 ?C of the ambient temperature and relative humidity of 53 %. These last results showed that the local chickens on susceptibility to humid tropical heat stress were smaller than in commercial hybrid chickens.
Journal of Thermal Biology
Early age thermal manipulation on the performance and physiological response of broiler chickens under hot humid tropical climate2020 •
Initial brooding temperature is critical for post-hatch growth of broiler chickens. A study was conducted to investigate the early age thermal manipulation (EATM) on the performance and physiological responses broiler chickens under hot humid tropical climate. A total of 260 unsexed day-old Arbor-acre broiler chicks were assigned to five thermal treatments of brooding temperature regimens having 4 replicates of thirteen birds each. The heat treatments were: initial brooding temperature of 35 � C for the first 2 days, and then decreased subsequently, gradually to 22 � C at 21 d of age (CT), initial temperature of 35 � C, sustained for the first 4 days and then decreased gradually (conventionally) (FD), initial temperature of 35 � C for the first 7 days (SD), the birds in CT, but the brooding temperature was raised to 35 � C again for another 3 days from day 7 (SD3), initial brooding temperature of 35 � C for the first 10 days (TD). Data were collected on daily feed intake and weekly body weights. Blood samples were collected from 8 birds per treatment weekly for the determination of plasma uric acid, triglycerides, triiodothyronine (T 3) and creatinine kinase. Data obtained were laid out in a Completely Randomized Design (CRD). Results showed that the final weights of the birds in FD were higher (P < 0.05) than those of the other treatments at the finisher phase. Feed intake of the birds in FD was higher than those of SD3 and TD. FCR of broiler chickens in CT, SD, SD3 and TD was higher than that of FD. The rectal temperature, plasma MDA and blood glucose of the thermally challenged birds in FD was generally better (P < 0.05) than those of the other treatments. It was concluded that EATM can be used to improve performance and also protect broiler chickens from acute heat stress at market age.
The objective of this study was to determine the effect of elevated air temperature in the first grow period on some physiological indicators of broiler chickens of different origin. Day-old Ross 308 and Hubbard Flex broiler chickens were assigned to 4 groups. Groups I (Ross 308) and II (Hubbard Flex) were kept under standard thermal conditions throughout rearing, and groups III (Ross 308) and IV (Hubbard Flex) were exposed to 10°C higher than recommended air temperature from 1 to 21 days of rearing. At 1, 21 and 42 days of the experiment, blood was collected from 10 birds in each group to determine T3 and T4, total protein, immunoglobulin complex, glucose, hemoglobin and hematocrit levels. The exposure to the thermal challenge decreased T3 and T4 levels at 21 days of rearing in both Ross 308 and Hubbard flex broilers compared to birds raised under standard thermal conditions. At 21 days of the experiment was observed a statistically significantly lower concentration of total protein in group I compared with group III and between group II and IV. There was no effect of elevated air temperature on the immunoglobulin complex concentration in the blood of birds of both genetic groups. In both genetic groups, the exposure to the thermal challenge caused a tendency to decrease the concentration of glucose. Statistically significant differences at 21 days of rearing of the hemoglobin content were observed between Ross 308 birds from groups I and III. The thermal challenge caused a statistically significant decrease in hematocrit levels in birds from both genetic groups at 21 days of the experiment. The thermal challenge upset the body’s homeostasis in both genetic groups of chickens, which possibly suggests that elevated air temperature during the first period of rearing has a negative effect on the welfare of broilers, regardless of their origin.
the objective of the study was to determine the effect of the stress factor of elevated air tempera- ture during the second rearing period on health, duration of tonic immobility, blood corticosterone levels and heterophil to lymphocyte ratio in commercial broilers representing three commercial lines. day-old hybro, hubbard flex and ross 308 broiler chickens were assigned to 6 groups. in the experimental groups, birds were exposed to elevated air temperature (30°c) in the rear- ing area from 30 to 34 days of age (4 days), and to standard thermal conditions (20–18°c) from 34 to 42 days of the experiment. the control groups consisted of broilers maintained throughout rearing under standard thermal conditions, with the air temperature of 31–33°c during the first days being gradually decreased to 20–18°c at 6 weeks of age. broiler mortality was monitored in all the groups throughout the experiment. the concentration of plasma corticosterone was deter- mined at 30, 34 and 42 days of the experiment in 7 birds from each group. blood smears were also performed to count lymphocytes (l) and heterophils (h), which made it possible to determine the h:l ratio. at 30, 34 and 42 days of the experiment, the duration of tonic immobility (ti) was exam- ined in 7 birds from each group. the thermal factor applied in the second rearing period elicited a stress reaction in the chickens of all lines, as indicated by the increased level of blood corticos- terone. however, ross 308 broilers were less tolerant of reduced welfare levels associated with elevated air temperature compared to hybro and hubbard flex broilers, as evidenced by higher mortality, the highest increase in blood corticosterone, longer duration of ti, as well as increased heterophil to lymphocyte ratio after the thermal factor was applied. the results of the present experiment show that ross 308 chickens are probably the least suitable for rearing during the summer production cycles.
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