Heat-stressed Broiler Chickens Research Articles

Gene expressions and metabolomic research on the effects of polyphenols from the involucres of Castanea mollissima Blume on heat-stressed broilers chicks

To study the effects of polyphenolic extract from involucres of Castanea mollissima Blume ( PICB: ), a novel approach using gene expression by real time polymerase chain reaction ( REAL-TIME PCR: ) coupled with metabolomic profiling technique was established to explain the mechanism of PICB on heat-stressed broiler chicks. Four thousand 28-day-old male Arbor Acres (AA) broilers were randomly assigned to 5 groups (4 replicates / group, 20 chicks / replicate), in which group 1 was normal control group fed with basic ration; groups 2, 3, 4, and 5 were fed with the basic ration with a supplementation of 0.2% Vitamin C ( VC: ), or 0.2%, 0.3%, or 0.4% of PICB respectively. After 1 wk of adaptation, heat stress was applied for 7 consecutive days. On d 3 and d 7 of heat stress, the chicks were sacrificed and sampled. The mRNA expression of heat stress protein 70 (HSP70), glutathione peroxidase ( GSH-PX: ), ornithine decarboxylase ( ODC: ), epidermal growth factor ( EGF: ) and epidermal growth factor receptor ( EGFR: ) were detected by real-time PCR using samples from jejunum mucosa. The serum and jejunum mucosa metabolomic profiles of PICB group showing best antioxidative effects and control group at d 3 were studied using the method of the gas chromatography - time of flight mass spectrometry ( GT-TOF-MS: ), followed by principal component analysis and partial least squares-discriminate analysis. Potential biomarkers were found using Student's t-test. The results showed mRNA expressions of HSP70, GSH-Px, ODC, EGF, and EGFR were altered by the supplementation of PICB. PICB exhibited antioxidative and growth promoting effects, and 0.3% PICB supplementation level exhibited the best. Three metabolites in the serum and 5 in the jejunum mucosa were identified as potential biomarkers. They were considered to be in accordance with antioxidative and growth promoting effects of PICB, which involved in the energy metabolism (sorbitol, palmitic acid), carbohydrate metabolism, amino acids metabolism (serine, L-ornithine), glutathione metabolism (glutamate, L-ornithine), GnRH signaling pathway (inositol), etc. These findings provided novel insights into our understanding of molecular mechanism of PICB effects on heat-stressed chicks.

Effects of mannan oligosaccharide and <i>Curcuma xanthorrhiza</i> essential oil on the intestinal morphologyand stress indicators of broilers subjected to cyclic heat stress

Abstract. An experiment was carried out that was intended to explore the growth performance, nutrient retention, and heat stress biomarkers of finishing broilers under cyclic heat stress (HS) as modulated by the supplementation of mannan oligosaccharide (MOS) and Curcuma xanthorrhiza essential oil (CXEO). Two hundred and forty 21-day-old Ross 308 male broilers were allocated to four experimental treatments, each of which was replicated six times with 10 broilers per replicate. The diets included a control (CON), CON + 5 g of MOS kg−1, CON + 400 mg of CXEO kg−1 of feed, and CON + 5 g of MOS kg−1 + 400 mg of CXEO kg−1. From day 22 to 42, birds were subjected to cyclic HS by exposing them to 33 °C for 10 h (from 07:00 to 17:00 LT) and 22 °C from 17:00 to 07:00. Dietary treatments did not have an effect on average daily feed intake, feed conversion ratio, the duodenal histomorphology, and relative visceral weights. Body weight, average daily gain, villus length, crypt depth, and the villus-length-to-crypt-depth ratio in the jejunum were significantly increased in birds fed MOS or MOS + CXEO diets (p < 0.05). The relative bursa weight of the control birds was lower (p < 0.05) compared to those fed the MOS diet. Compared with CON, dietary treatments reduced corticosterone and creatine kinase levels, the heterophile-to-lymphocyte ratio, and mRNA levels of heat shock protein 70 in the breast muscle and jejunum (p < 0.05). It was concluded that dietary supplementation of either MOS or CXEO alone or in combination may reduce some of the harmful effects of HS in broiler chickens.

Apple peel waste as a natural antioxidant for heat-stressed broiler chickens.

This study was conducted to evaluate the effects of processed apple peel waste (APW), alone or in combination with an enzyme, as a natural antioxidant on broiler chickens under heat stress. A total of 360 unsexed, 28-day-old broilers were assigned to 6 dietary treatments with four replicates (15 broilers per pen). The experiment consisted of a 3 × 2 factorial arrangement with three levels of apple peel waste (0, 50 or 100 g/kg of diet) and two levels of enzyme (0 or 500 mg/kg, ZY Multi(®)). Inclusion of 100-g APW/kg of diet decreased broiler weight gain at 42 days of age. Inclusion of 50 and 100-g APW/kg of diet increased gizzard and small intestine weights. Feeding 50 and 100-g APW/kg increased high-density lipoprotein (HDL) cholesterol and decreased low-density lipoprotein (LDL) cholesterol and malondialdehyde in blood serum at 49 days of age. At 49 days of age, apparent ileal protein digestibility was reduced when 50 and 100-g APW/kg were used in the diet. This study showed that feeding APW up to 50 g/kg from 28 to 49 days of age increased HDL cholesterol and decreased LDL cholesterol in serum and had no adverse effect on broiler performance.

Effect of bee pollen and propolis (bee glue) on growth performance and biomarkers of heat stress in broiler chickens reared under high ambient temperature

Effect of bee pollen and propolis (bee glue) on growth performance and biomarkers of heat stress in broiler chickens reared under high ambient temperature

A study of the employment of melatonin supplementation and darkness regime on reducing the negative effects of acute heat stress and mortality in broiler chickens

Background: Heat stress is one of the most important environmental stressors challenging poultry production worldwide. Understanding and controlling environmental stressors is crucial for successful poultry production. OBJECTIVES: The aim of the present study was to investigate the effects of melatonin supplementation and darkness regime on reducing the negative effects of heat stress in broiler chickens. METHODS: A total of 400 broiler chickens (Arian) were obtained and subjected to four different groups. The control chickens were grown in normal conditions without receiving any treatment. The positive control birds were grown similar to the control but exposed to an acute heat stress for 6 h/d from days 35 to 40. The dark group chickens were reared under a dark schedule and exposed to heat stress. The birds of the fourth group were reared similar to the positive control but received 40 ppm melatonin in the diet from days 30 to 40 of age. Dead birds were autopsied. The weekly growth performance of chickens was determined and blood samples were taken for hormonal analysis. RESULTS: The number of dead birds due to heat stress was significantly decreased in chickens subjected to the dark program and/or those which received melatonin in the diet compared with those of positive control chickens. Such differences were accompanied with the significantly lower levels of plasma T3, T3/T4 and corticosterone in these groups of chickens. Additionally, plasma thiobarbituric acid reacting substances level was significantly higher in positive control broilers compared to their counterparts. CONCLUSIONS: Our findings indicate a reduction of metabolic rate and heat production in dark regime and melatonin supplementation that can reduce the side effects of heat stress and, therefore, reduce the mortality rate.

Comparative Studies Ascorbic Acid and Hibiscus sabdariffa Calyces against Heat-Stress Inclusion in Broiler Chicken

This study was done to investigate the effect of inclusion of ascorbic acid (AA) and Hibiscus sabdariffa in broiler chicken feed on haematological and oxidative stress parameters during the hot-dry season. Sixty day old chicks were used for the experiment, and were assigned to three dietary treatments with 20 birds per treatment and four replicate in a completely randomized design. Treatment 1 was the control with no supplements, treatment 11 was supplemented with AA at the rate of 500 mg/kg in feed and treatment 111 had Hibiscus sabdariffa at the rate of 2.5 % inclusion rate in feed. On the last day of the experiment half of the birds were randomly selected from each dietary group and blood sample (2 ml) was obtained through the wing web and divided into 2 parts; one for determination of haematological parameters while the second part was centrifuged and the resultant serum harvested and stored. The results indicated that the values of PCV, haemoglobin and total erythrocyte count obtained in T1 were all significantly (P < 0.05) lower than the recorded corresponding value in T2 and T3. The recorded values of malondialdehyde obtained in T1 was significantly (P < 0.05) higher than the values recorded in T2 and T3 while the values of superoxide dismutase, catalase and glutathione peroxidase were significantly (P < 0.05) higher than the obtained values in T2 and T3. The fragiligram was shifted more to the left in T3 than the other 2 treatments (P < 0.05). In conclusion dietary supplementation of AA and Hibiscus sabdariffa calyces alleviated the adverse effects of heat stress in broiler chicken. It is thus recommended that Hibiscus sabdariffa calyces in the diets at the rate of 2.5 % could provide ameliorative effect against heat stress in broiler chicken during the hot-dry season.

The association of Hsp90 expression induced by aspirin with anti-stress damage in chicken myocardial cells.

The protective effect of aspirin during exposure to heat stress in broiler chickens was investigated. We assayed pathological damage, expression and distribution of Hsp90 protein and hsp90 mRNA expression in chicken heart tissues after oral administration of aspirin following exposure to high temperature for varying times. Heat stress induced increases in plasma aspartate aminotransferase, creatine kinase and lactate dehydrogenase activities while causing severe heart damage, which was characterized by granular and vacuolar degeneration, nuclear shrinkage and even myocardium fragmentation in cardiac muscle fibers. After aspirin administration, myocardial cells showed fewer pathological lesions than broilers treated with heat alone. A high positive Hsp90 signal was always detected in the nuclei of myocardial cells from broilers treated with aspirin, while in myocardial cells treated with heat alone, Hsp90 in the nuclei decreased, as did that in the cytoplasm. Aspirin induced rapid and significant synthesis of Hsp90 before and at the initial phase of heat stress, and significant expression of hsp90 mRNA was stimulated throughout the experiment when compared with cells exposed to heat stress alone. Thus, specific pre-induction of Hsp90 in cardiovascular tissue was useful for resisting heat stress damage because it produced stable damage-related enzymes and fewer pathologic changes.

Efficacy of turmeric (Curcuma longa) as antioxidant in combating heat stress in broiler chicken

A study was undertaken to evaluate the antioxidants potential of herbal turmeric (Curcuma longa) in combating heat stress on120 broiler chicks in hot summer months. The day old Vencobchicks were randomly divided into five groups in a completely randomized design. The dietary treatments were basal diet (no antioxidant supplementation, BD), and the other four diets were BD supplemented with vitamin E (200 mg/kg), vitamin E (200 mg/kg) + Se (0.15 mg/kg), Turmeric (0.2%) and turmeric (0.4%), respectively. Additionally, a group of 24 chicks was raised separately in stress free environment on BD without any antioxidant supplementation and this diet acted as control. Blood was collected at 4th and 6th week of age from 12 birds from each group. Enzymatic and non-enzymatic antioxidant concentrations were estimated in plasma and cortisol concentration was analyzed in serum. Birds were vaccinated with Newcastle disease (ND) vaccine on 7th and 21st day and humoral response (HI) was assessed in sera samples at 4th and 6th wk of age. Cell mediated immune response (CMI) was assessed by injecting Phytohaemagglutinin (PHA-P) intra dermally into inter digital fold at the end of 4th and 6th wk and increase in the skin thickness was measured after 24 h. At the end of 42nd day, 6 birds from each group were sacrificed to observe the histological changes in bursa, spleen and liver. Serum cortisol was highest in heat stressed birds and lowest in heat stress free (control) group. On contrary, the activities of enzymatic antioxidants i.e. superoxide dismutase (SOD), glutathione peroxidase (GSH-Px), catalase and non enzymatic antioxidants (reduced glutathione) and immunological indices HI and CMI were lower (P<0.01) in heat stressed birds compared to control group. Inclusion of vitamin E in combination with Se showed the highest (P<0.01) response in reducing cortisol levels and improving antioxidant and immune status followed by vitamin E sole supplementation. Turmeric supplementation at either dose significantly (P<0.01) lowered serum cortisol and increased the antioxidant activity and immune status. However, the improved response obtained was more significant (P<0.01) with Turmeric supplementation at higher dose (0.4%) than supplementation at lower (0.2%) level. The study indicated that Turmeric at 0.4% level of supplementation to basal diet was effective in lowering the oxidative damage caused due to heat stress, but it was less effective than supplementation of vitamin E either alone (or) in combination with Se.

Effects of Chromium (III) Picolinate and Chromium (III) Picolinate Nanoparticles Supplementation on Growth Performance, Organs Weight and Immune Function in Cyclic Heat Stressed Broiler Chickens

Effects of Chromium (III) Picolinate and Chromium (III) Picolinate Nanoparticles Supplementation on Growth Performance, Organs Weight and Immune Function in Cyclic Heat Stressed Broiler Chickens

Heat shock protein 70 mRNA expression and immune response of heat-stressed finishing broilers fed propolis (bee glue) supplementation

Abstract. This 2×2 factorial experiment investigated the efficacy of propolis (bee glue; BG) in ameliorating heat-stress-induced impairment of growth performance, the hematological profile, intestinal morphology, and biomarkers of heat stress in broilers. Two hundred and forty 21-day old Ross 308 male broiler chicks were allocated to four experimental treatments in six replicates of 10 birds each. The main factors were composed of diet (basal diet or addition of 3 g kg−1 of BG) and temperature (thermoneutral or heat stress). Broilers subjected to heat stress had reduced average daily gain (ADG) and average daily feed intake (ADFI); a higher heterophil level and heterophil-to-lymphocyte ratio, and a lower lymphocyte level; upregulated mRNA expression of 70 kDa heat shock protein (HSP70) levels in heart, kidney, and breast muscle; and shorter jejunal villus height, deeper crypt depth, and a lower ratio of villus-height-to-crypt-depth compared with those broilers raised in thermoneutral conditions. Supplemental BG increased ADG, jejunal villus height, and the villus-height-to-crypt-depth ratio and decreased the feed-to-gain ratio and creatine kinase and lactate dehydrogenase levels in breast muscle compared with the birds who received control diets. The inclusion of BG in diets significantly decreased the mRNA expression of HSP70 levels in heart, kidney, and breast muscle in birds subjected to heat challenge. These results indicate that the BG-supplemented diet was effective in partially ameliorating adverse effects in resistance to heat stress in broiler chickens.

Effects of feeding Bacillus subtilis to heat stressed broiler chickens with or without an antibiotic growth promoter

The effects of feeding probiotic (PB) with or without Lincomycin 2.2% (AGP) were investigated in broiler chickens during summer. Seven hundred Cobb-500 one day old straight run broiler chicks were randomly distributed into four dietary treatments each of five replications. Four diets were compared: control; control diet plus PB (Bacillus subtilis DSM17299) at a level of 50g/100kg; control plus (AGP) at a level of 15g/100kg and control plus a combination of PB and AGP (50gm/100kg and 15g/100kg respectively). Control birds were fed on a corn-soybean based starter mash that contained ME 3000 kcal/kg and CP 24.39% from 0-21 days of age and a corn-soybean based grower mash of ME 3100 kcal/kg and CP 20.43% during 22-35 days of age. The records were kept of feed intake (FI), body weight and mortality while weight gain, feed conversion ratio (FCR) and survivability were calculated. Temperature and humidity were recorded four times daily except during extreme heat stress when measurements were made more frequently. One bird that was close to average of pen weight was taken from each replication at the end of the trial and the birds were sacrificed to determine carcass characteristics. Both performance and carcass yield data were statistically analyzed. Birds that received PB and a combination of PB +AGP treatments showed significant differences (P&lt;0.01) from control with respect to body weight gain and FCR while feeding AGP alone although showed a decrease in feed intake. Abdominal fat was significantly (P&lt;0.01) reduced in PB treated birds. Higher mortality was encountered in control group. Both PB alone and a combination of AGP treatments were able to show improved performance and reduced mortality, feeding PB alone may be practiced on the combined grounds of improved performance, efficiency in combating heat stress and to discourage the use of AGP in broiler diet.Asian J. Med. Biol. Res. June 2015, 1(1): 80-88

Effects of dietary Satureja khuzistanica essential oils and α-tocopherol on productive performance, organ weights, blood lipid constituents and antioxidative potential in heat stressed broiler chicks

Summary A total of 320 one-day-old Ross 308 broiler chicks were used to study the effects of dietary supplementation of 0, 200, 400 and 600Â mg/kg SkEO or 200Â mg/kg α-tocopherol on productive performance, organ weights, blood antioxidant stability and lipid constituents in birds raised in thermo-neutral or cyclic heat stress conditions in a 42-d experiment. Heat stress significantly suppressed FCR (PÂ <Â 0.001) and performance efficiency index (PÂ <Â 0.05) through day 42 of age. Dietary administration of 400Â mg/kg SkEO promoted DWG (PÂ <Â 0.05), FCR (PÂ <Â 0.05) and EPEF (PÂ <Â 0.05) through day 42 of age with no change in FI and mortality compared to the birds receiving α-tocopherol and control diets. Serum CHOL and LDL concentrations were decreased significantly in birds fed on a diet containing 400Â mg/kg SkEO compared to control birds (PÂ <Â 0.001). Lipid stability and antioxidant power of the blood were improved by inclusion of 200 and 400Â mg/kg SkEO and 200Â mg/kg α-tocopherol as shown by lowered serum MDA concentration and elevated GPx activity. Abdominal fat percentage tended to be decreased (PÂ =Â 0.06) in heat stressed birds compared to those raised in normal thermal conditions at day 42 of age. Inclusion of 400 and 600Â mg/kg SkEO and 200Â mg/kg α-tocopherol in broiler diets significantly decreased abdominal fat in both heat stressed and non-stressed birds at day 42 of age. It was concluded that supplementation of SkEO in broiler diets at 400Â mg/kg may result in economic benefits in broiler flocks through improved FCR and economic efficiency factor. The same dietary dose may cause decreased carcass fat and improved antioxidant capacity of the blood. The results did not demonstrate any clear advantage for dietary SkEO in heat stressed birds compared to those kept in normal temperature conditions.

Mortality, production performance, water intake and organ weight of the heat stressed broiler chicken given savory (Satureja khuzistanica) essential oils through drinking water

An experiment was conducted to examine the effects on mortality, production performance, water intake (WI) and organ weight of Satureja khuzistanica essential oil (SkEO) using 720 one-day-old Arian broiler chicks in a 42-day trial. Experimental treatments were addition of 0 (control−), 200, 300, 400 and 500 mg/L SkEO or 500 mg/L polysorbate-80 (control+) into drinking water. The birds were kept under natural ambient temperatures 4–6°C above standard recommendation from days 22 to 42 of age. Addition of SkEO into drinking water at 200 and 500 mg/L decreased weight gain (P < 0.05) of the birds from days 29 to 35 of age with no differences in feed intake (FI) and feed conversion ratio (FCR) compared to control groups (P > 0.05). Addition of 300 and 500 mg/L SkEO into water increased mortality rate of the birds mainly from days 29 to 42 of age. The calculated European broiler index was greater for the birds receiving drinking water supplemented with 400 mg/L of SkEO compared with the other birds. In conclusion, administration of SkEO at 400 mg/L through drinking water to heat stressed broiler chickens may result in improved production performance efficiency.

Effects of Satureja khuzistanica essential oils in drinking water on mortality, production performance, water intake, and organ weights in broiler chickens reared under heat stress condition.

An experiment was conducted to examine the effects on mortality, production performance, water intake (WI), and organ weight of Satureja khuzistanica essential oil (SkEO) using 720 1-day-old Arian broiler chicks in a 42-day trial. Experimental treatments were addition of 0 (control−), 200, 300, 400, and 500 mg/L SkEO or 500 mg/L polysorbate 80 (control+) into drinking water. The birds were kept under natural ambient temperatures 4 to 6 °C above standard recommendation from days 22 to 42 of age. Addition of SkEO into drinking water at 200 and 500 mg/L decreased weight gain (P < 0.05) of the birds from days 29 to 35 of age with no differences in feed intake (FI) and feed conversion ratio (FCR) compared to control groups (P > 0.05). Supplementation of drinking water with 200, 300, 400, and 500 mg/L SkEO resulted in a 0.47, 4.40, 8.60, and 12.93 % decrease in WI, respectively, from days 1 to 42 of age. The calculated European broiler index was greater for the birds received 400 mg/L of SkEO in their drinking water compared with that of the other birds (P < 0.05). Pancreas percentage was increased for the birds received 200 to 500 mg/L SkEO at days 21 and 42 of age compared with that of the control− birds (P < 0.05). The gall bladder weight was 17.56, 40.50, 12.16, and 38.73 % greater for the birds received 200, 300, 400, and 500 mg/L SkEO compared with that of the control− birds, respectively. The results showed that an addition of 400 mg/L SkEO into drinking water for heat-stressed broiler chickens improves economic efficiency possibly by promoting digestion process, creating miniscule improvement in FCR and lowered mortality rate.

Behavioral changes and feathering score in heat stressed broiler chickens fed diets containing different levels of propolis

This experiment was conducted to evaluate the effects of dietary supplementation of green Brazilian propolis on behavioral patterns and feather condition of heat stressed broiler chickens. Five hundred and four (504) male Ross 708 broiler chicks at 15-day old were randomly allotted to six dietary treatments containing 0 (control), 100, 250, 500, 1000 and 3000mgkg−1 propolis, respectively. Each treatment consisted of four replicates of 21 birds each. Heat stress at 32°C was applied daily from 08:00 am to 17:00 pm from day 15–42. Twelve birds per treatment were randomly taken and marked with livestock color for behavioral observation. Treatment effects on behavioral patterns were recorded using direct observation instantaneous scan sampling technique. At the end of the experiment (42 days of age) the three birds used for behavioral observation were feather scored (from 1 to 5); while all birds (504) were individually scanned for primary feather abnormalities. The results indicated that the effects of using propolis as a feed additive for broilers reduced heat stress behavior, especially dietary treatment with 250 or 3000mgkg−1 propolis, by increasing bird walking activities and reducing panting behaviors (P<0.05, respectively). Moreover, 250mgkg−1 propolis (P<0.05) increased standing behavior also. Walking activities was also increased in the birds fed with 100mgkg−1 propolis (P<0.05). There were no significant (P>0.05) treatment effects on sitting, preening, feeding, drinking, wing elevations and feather pecking activities. Propolis at current doses did not significantly (P>0.05) improve feather scoring, but reduced (P=0.048) abnormal shape of primary feathers. The current results support that propolis treatment may be considered as a protective management practice in broiler chickens to alleviate the negative effects of heat stress, but further investigations may requested to determine the best type, dose, time and duration of its administration.

Selenium as a feed supplement for heat-stressed poultry: a review.

Heat stress is associated with compromised performance and productivity in poultry due to declines in feed intake, nutrient utilization, growth rate, egg production and quality, and feed efficiency. Emerging evidences have shown that acute heat exposure results in increased production of free radicals and causes oxidative damage to lipids, proteins, and DNA. Additionally, heat stress can influence immune response by changing the expression of cytokines and by making the immune cells more susceptible to oxidative stress. Selenium, as a part of specific selenoproteins, can help to maintain antioxidant defenses, thereby preventing damages to tissues. An optimum response with supplementation of selenium in diet has been found to improve feed intake, body weight gain, feed efficiency, egg production and quality, and antioxidant status in heat-stressed poultry. Selenium compounds are also known to improve immune responses by altering the production of certain cytokines secreted by cells of the immune system and by enhancing the resistance of the immune cells to oxidative stress. It was reported that selenium supplementation had inhibitory effects on tumor necrosis factor alpha levels in heat-stressed broiler chicks, but the details are not completely elucidated. In the present review, the effect of selenium on production performance, nutrient utilization, antioxidative status, and immune responses of heat-stressed poultry is summarized.

Effects of Withania coagulans fruit powder and vitamin C on growth performance and some blood components in heat stressed broiler chickens

This study was conducted to study the effect of Withania coagulans (WC) fruit powder and vitamin C (VC) on growth performance and some blood components in heat stressed broilers. The experiment was conducted as a 2×3 factorial arrangement of treatments with 2 concentrations of VC (0 and 250mg/kg of diet) and 3 concentrations of WC (0, 2.5, and 5g/kg of diet). Each of 6 dietary treatments was fed to 4 replicate pens (9 broiler chickens/pen) from 25 to 42d of age. The house temperature was set at 34°C±2 (from 0900 to 1700h) throughout the experiment. Feed intake (FI), body weight gain (BWG), and feed to gain ratio (F:G) were calculated at the end of the experiment. At d 42 of age, the blood samples were collected from 1 broiler chicken per pen, and glucose and cholesterol concentrations, white blood cell (WBC) count, and activity of glutathione peroxidase (GPX) were determined. The FI and BWG increased by 5.5% and 12.7%, respectively, and F:G decreased by 6.5% with VC supplementation (P≤0.01). As dietary inclusion of WC increased from 0 to 5g/kg, both FI and BWG increased by 5.6% (linear, P≤0.023). The activity of GPX increased (P≤0.05) by 20.57% with addition of VC to the diet, whereas no effect of WC was observed. Neither VC nor WC had effect on blood cholesterol and glucose concentrations, WBC counts, relative weight of bursa of Fabricius, spleen, and liver, and relative length of the duodenum, jejunum, and ileum. It is concluded that dietary supplementation of 250mg VC/kg or 5g WC fruit powder/kg improved the growth performance of heat stressed broiler chickens.

Response of Heat-Stressed Broiler Chicks to Dietary Supplementation with Some Commercial Herbs

Response of Heat-Stressed Broiler Chicks to Dietary Supplementation with Some Commercial Herbs

Bioquímica sanguínea y concentración plasmática de corticosterona en pollo de engorde bajo estrés calórico

Las altas temperaturas ambientales propician susceptibilidad al estrés calórico en los pollos de engorde, lo que genera cambios metabólicos. Se buscó determinar los cambios en la bioquímica sanguínea y la concentración plasmática de corticosterona del pollo de engorde sometido a estrés calórico crónico y a las condiciones de temperatura ambiental del piedemonte amazónico colombiano, sobre las concentraciones plasmáticas de corticosterona, glucosa, proteínas totales, albumina, globulina, sodio, cloro, potasio, magnesio, fósforo y calcio. Se utilizaron pollos machos de 2 estirpes de 21 días de edad, distribuidos en un diseño experimental irrestrictamente al azar, en un esquema bifactorial, con 4 tratamientos. Se hicieron 5 repeticiones por tratamiento y 25 animales por unidad experimental. Las aves fueron alimentadas con una dieta básica de maíz y torta de soya con 3,100 Kcal de EM y 19,5 % de proteína hasta los 42 días de edad. El factor estirpe no tuvo efecto en las variables evaluadas (p ≥ 0,05). No obstante, existió diferencia estadística significativa (p ≤ 0,05) en todas las variables evaluadas al ser comparadas las concentraciones de los metabolitos de las aves en condiciones de estrés calórico crónico con las de las aves expuestas a las condiciones de temperatura del piedemonte amazónico colombiano. Se concluyó que la bioquímica sanguínea sufrió modificaciones significativas bajo las 2 temperaturas experimentales, con mayor detrimento fisiológico de las aves con estrés calórico crónico. La concentración de corticosterona se constituyó en el indicador más sensible y constante de la condición fisiológica de estrés crónico por calor.

Effects of long-term heat stress in an experimental model of avian necrotic enteritis

Stressful conditions are predisposing factors for disease development. Heat stress is one of the most important stressors in poultry production. The reemergence of some previously controlled diseases [e.g., avian necrotic enteritis (NE)] has been extensively reported. The combination of bacterial infection and certain environmental factors have been reported to trigger the disease. The aim of this study was to analyze the effects of long-term heat stress (35 ± 1°C) on the development of NE in broiler chickens. For this purpose, 60 male broiler chickens were divided into the following 6 groups: control group (C), heat stressed control group (C/HS35), thioglycolate group (T), thioglycolate heat-stressed group (T/HS35), infected group (I), and infected heat-stressed group (I/HS35). The poultry of groups I and I/HS35 were experimentally infected with Clostridium perfringens via their feed from 15 to 21 d of life. Heat stress (35 ± 1°C) was constantly applied to the birds of the stressed groups from 14 to 21 d of life. The infected and heat-stressed broiler chickens presented a trend toward a decrease in gross lesion scores and significantly lower microscopic scores of necrosis in the duodenum and jejunum (P < 0.05), lower fusion of villi in the duodenum (P < 0.05), and lower congestion scores in the jejunum and ileum (P < 0.05) in relation to infected and non-heat-stressed chickens. Broilers of I/HS35 group also exhibited small number of heterophils in the duodenum and jejunum compared with those of the I group (P < 0.05). Furthermore, the duodenum and jejunum of infected and heat-stressed broilers showed lower number of clostridia on the intestinal mucosa (P < 0.05). Data were discussed in light of a heat stress induced reduction on intestinal inflammation via a decrease in heterophil migration to the intestinal mucosa, which in turn might have reduced tissue damage during inflammation, hence preventing the development of a more severe form of NE.