Beneficial Impact of Hypercapnic Conditions During Early Incubation on Broiler Hatchability. Embryo Mortality and Postnatal Performance

We assessed the extent to which CO2 levels altered different hatching and chick parameters. In Experiments 1 and 2, a total of 16,184 eggs from Cobb 500 breeders were incubated in single stage incubators under three different conditions: (a) standard ventilated incubator (CON, Exp.1 and 2); (b) increasing CO2 levels during the first 10 days of incubation until 0.7% (V7000, Exp. 1) and (c) until 0.8% (V8000, Exp. 2). High levels of CO2 improved hatchability, possibly due to lower embryo mortality from ED18 to ED21. Internal and external pipping in experiment V8000 started later than in CON; nevertheless, the hatch still occurred before in V8000 as a result of the shorter durations of external pipping and hatch. In Experiment 3, a total of 12,138 eggs from Cobb 500 were incubated in single stage incubators under three different conditions: (a) standard ventilated incubator (CON); (b) increasing CO2 levels until 1.0% with ventilation (V10000); and (c) increasing CO2 levels until 1.0% without ventilation (NV10000). Hypercapnic conditions led to better hatchability and lower embryo mortality from ED18 to ED21. Internal pipping started earlier in NV10000, but only V10000 differed from CON in terms of the average time for hatch. Hypercapnic groups also showed shorter durations of external pipping and hatch when compared to CON. Post-hatch analysis revealed no differences among incubation conditions in terms of body weight gain, feed conversion ratio, mortality by sudden death syndrome, and production factor. Nevertheless, V10000 showed a lower mortality by ascites and a better viability when compared to CON, while NV10000 presented a higher mortality by other causes. Altogether, our findings indicate that in addition to not being detrimental to embryo survival, high CO2 levels reduce embryonic mortality at 18-21 days of incubation and increase hatchability.(AU)

Effects of Phytogenic Additives and Organic Acids, alone or in combination, on the Performance, Intestinal Quality and Immune Responses of Broiler Chickens

ABSTRACT The present study was conducted to evaluate the effects of phytogenic additives (PA) and organic acids (OA), alone or in combination, on the performance, intestinal histomorphometry and lipid oxidation, and immune responses of broiler chickens. In this experiment, 820 one-day-old chicks were distributed according to a completely randomized design in a 2 × 2 + 1 factorial arrangement, with four replicates of 41 broilers each. The dietary treatments consisted of a control diet with no PA or OA (CD); CD with OA and no PA (CD+OA-PA); CD with PA and no OA (CD+PA-CD); CDwith both PA and OA (CD+PA+CD); and CD + avilamycin + monesin sodium. Broiler performance was not affected by the alternative feed additives, except from 1 to 21 days, when broilers fed the CD or CD+PA+OA diets showed higher body weight gain than those fed the CD with only OA. The broilers fed the diet containing avilamycin and monensin presented better performance. The supplementation of PA and OA increased bursalcortical area on21 and 42 days post-hatch. On 21 days post-hatch, broilers fed the AGP diet presented higher ileal villus height than those fed the control diet. The pH values of the jejunum content were reduced on the OA-fed chickens. Higher villus height and crypt depth were found in the alternative additive-fed chickens on 7 days post-hatch. On 42 days post-hatch, the percentage of the bursal cortex increased in PA-fed broilers; however, there was no increase in antibody production. The PA-fed chickens presented lower thiobarbituric acid reactive substances (TBARS) values in the small intestine. The dietary supplementation of phytogenic additives, individually or in combination associated with organic acids, does not affect broiler live performance or intestinal histomorphometry; however, it enhances immune responses and intestinal quality.(AU)

Effects of Phytogenic Additives and Organic Acids, alone or in combination, on the Performance, Intestinal Quality and Immune Responses of Broiler Chickens

ABSTRACT The present study was conducted to evaluate the effects of phytogenic additives (PA) and organic acids (OA), alone or in combination, on the performance, intestinal histomorphometry and lipid oxidation, and immune responses of broiler chickens. In this experiment, 820 one-day-old chicks were distributed according to a completely randomized design in a 2 × 2 + 1 factorial arrangement, with four replicates of 41 broilers each. The dietary treatments consisted of a control diet with no PA or OA (CD); CD with OA and no PA (CD+OA-PA); CD with PA and no OA (CD+PA-CD); CDwith both PA and OA (CD+PA+CD); and CD + avilamycin + monesin sodium. Broiler performance was not affected by the alternative feed additives, except from 1 to 21 days, when broilers fed the CD or CD+PA+OA diets showed higher body weight gain than those fed the CD with only OA. The broilers fed the diet containing avilamycin and monensin presented better performance. The supplementation of PA and OA increased bursalcortical area on21 and 42 days post-hatch. On 21 days post-hatch, broilers fed the AGP diet presented higher ileal villus height than those fed the control diet. The pH values of the jejunum content were reduced on the OA-fed chickens. Higher villus height and crypt depth were found in the alternative additive-fed chickens on 7 days post-hatch. On 42 days post-hatch, the percentage of the bursal cortex increased in PA-fed broilers; however, there was no increase in antibody production. The PA-fed chickens presented lower thiobarbituric acid reactive substances (TBARS) values in the small intestine. The dietary supplementation of phytogenic additives, individually or in combination associated with organic acids, does not affect broiler live performance or intestinal histomorphometry; however, it enhances immune responses and intestinal quality.

Effect of incubator type and broiler breeder age on hatchability and chick quality

Two experiments were conducted to evaluate the effect of broiler breeder age and incubator type on hatching parameters, hatch window, embryo diagnosis results, and hatchling physical quality. The treatments consisted of a combination of three broiler breeder ages (29, 35 and 59 weeks of age) and two incubator types (single stage, SS; or and multiple stage, MS). A completely randomized design in a 3x2 factorial arrangement was applied. In Experiment I, 1,896 eggs were used and 360 eggs in Experiment II. There was an interaction between breeder age and incubator type only for hatchling physical quality score. Independently of incubator type, hatchability rate, late embryo mortality, and egg contamination were higher in the eggs laid by older breeders (59-wk-old). Early mortality (0-4 days) was higher in the embryos from young breeders (29-wk-old). A shorter hatch window birth was obtained in the SS incubator, resulting in higher hatchling body weight relative to egg weight, and better hatchling physical quality score. Both types of incubators provide good conditions for embryo development; however, the physical quality of chicks derived from eggs from intermediate-aged breeders (35-wk-old) is better when eggs are incubated in SS incubators.

Effect of incubator type and broiler breeder age on hatchability and chick quality

Two experiments were conducted to evaluate the effect of broiler breeder age and incubator type on hatching parameters, hatch window, embryo diagnosis results, and hatchling physical quality. The treatments consisted of a combination of three broiler breeder ages (29, 35 and 59 weeks of age) and two incubator types (single stage, SS; or and multiple stage, MS). A completely randomized design in a 3x2 factorial arrangement was applied. In Experiment I, 1,896 eggs were used and 360 eggs in Experiment II. There was an interaction between breeder age and incubator type only for hatchling physical quality score. Independently of incubator type, hatchability rate, late embryo mortality, and egg contamination were higher in the eggs laid by older breeders (59-wk-old). Early mortality (0-4 days) was higher in the embryos from young breeders (29-wk-old). A shorter hatch window birth was obtained in the SS incubator, resulting in higher hatchling body weight relative to egg weight, and better hatchling physical quality score. Both types of incubators provide good conditions for embryo development; however, the physical quality of chicks derived from eggs from intermediate-aged breeders (35-wk-old) is better when eggs are incubated in SS incubators.(AU)

In ovo supplementation of 25(OH)D3 to broiler embryos

A dose of 0.3 mL of water solution containing 0.00 (control), 0.625, 1.250 or 1.875 µg of 25-hydroxy cholecalciferol (25(OH)D3) was administered to 312 fertile eggs derived from 49-w-old Cobb 500 broiler breeders on the 17th day of incubation (DE17) via allantoic cavity. After treatment, eggs were distributed and maintained until hatching in four incubators set at 37.8 ºC and 55% RH. Each incubator received eggs from all treatments, according to a block design with four treatments of 77-79 replicates each. Hatching was checked every two hours from 484h to 512h of incubation to evaluate productivity and chick qualities. Chicks were housed until 10 days of age in heated battery cages according to a block design with four treatments of 10 replicates of six chicks each for performance and mortality evaluation. Mean hatching time of the chicks treated with 25(OH)D3 during the embryonic phase occurred 4 to 5 h earlier than control group (502:31h), with no effects on hatching or neonate qualities. An inverse linear effect of 25(OH)D3 dose on chick body weight at hatching was observed, but 10-d-old broiler performance and mortality were not affected. The fast body weight recovery of the broilers obtained from the embryos supplemented with the highest 25(OH)D3 level was recorded until 10 days of rearing, equaling final mean body weights (p>0.05) among experimental groups. The results of this study indicate the potential use of 25(OH)D3 as exogenous vitamin supplementation to embryos a few days before hatching without affecting neonate qualities and 10-d-old broiler chicken performance.

In ovo supplementation of 25(OH)D3 to broiler embryos

A dose of 0.3 mL of water solution containing 0.00 (control), 0.625, 1.250 or 1.875 µg of 25-hydroxy cholecalciferol (25(OH)D3) was administered to 312 fertile eggs derived from 49-w-old Cobb 500 broiler breeders on the 17th day of incubation (DE17) via allantoic cavity. After treatment, eggs were distributed and maintained until hatching in four incubators set at 37.8 ºC and 55% RH. Each incubator received eggs from all treatments, according to a block design with four treatments of 77-79 replicates each. Hatching was checked every two hours from 484h to 512h of incubation to evaluate productivity and chick qualities. Chicks were housed until 10 days of age in heated battery cages according to a block design with four treatments of 10 replicates of six chicks each for performance and mortality evaluation. Mean hatching time of the chicks treated with 25(OH)D3 during the embryonic phase occurred 4 to 5 h earlier than control group (502:31h), with no effects on hatching or neonate qualities. An inverse linear effect of 25(OH)D3 dose on chick body weight at hatching was observed, but 10-d-old broiler performance and mortality were not affected. The fast body weight recovery of the broilers obtained from the embryos supplemented with the highest 25(OH)D3 level was recorded until 10 days of rearing, equaling final mean body weights (p>0.05) among experimental groups. The results of this study indicate the potential use of 25(OH)D3 as exogenous vitamin supplementation to embryos a few days before hatching without affecting neonate qualities and 10-d-old broiler chicken performance.

In ovo supplementation of 25(OH)D3 to broiler embryos

A dose of 0.3 mL of water solution containing 0.00 (control), 0.625, 1.250 or 1.875 µg of 25-hydroxy cholecalciferol (25(OH)D3) was administered to 312 fertile eggs derived from 49-w-old Cobb 500 broiler breeders on the 17th day of incubation (DE17) via allantoic cavity. After treatment, eggs were distributed and maintained until hatching in four incubators set at 37.8 ºC and 55% RH. Each incubator received eggs from all treatments, according to a block design with four treatments of 77-79 replicates each. Hatching was checked every two hours from 484h to 512h of incubation to evaluate productivity and chick qualities. Chicks were housed until 10 days of age in heated battery cages according to a block design with four treatments of 10 replicates of six chicks each for performance and mortality evaluation. Mean hatching time of the chicks treated with 25(OH)D3 during the embryonic phase occurred 4 to 5 h earlier than control group (502:31h), with no effects on hatching or neonate qualities. An inverse linear effect of 25(OH)D3 dose on chick body weight at hatching was observed, but 10-d-old broiler performance and mortality were not affected. The fast body weight recovery of the broilers obtained from the embryos supplemented with the highest 25(OH)D3 level was recorded until 10 days of rearing, equaling final mean body weights (p>0.05) among experimental groups. The results of this study indicate the potential use of 25(OH)D3 as exogenous vitamin supplementation to embryos a few days before hatching without affecting neonate qualities and 10-d-old broiler chicken performance.(AU)

Morphological changes of the intestinal mucosa of broilers and layers as affected by fasting before sample collection

The present study aimed at evaluating the histo-morphological changes resulting from different fasting periods before the collection of tissue samples in different segments of the small intestine (duodenum, jejunum and ileum) of 7-d-old male chicks of a broiler and a layer strain. A completely randomized experimental design in in a 2x7 factorial arrangement, being two strains with different growth rates (Ross 308 and HyLine® W36) and seven fasting periods (0, 2, 4, 6, 8, 10 and 12 hours ), with six replicates, totaling 84 birds. The comparison of the morphometrics of the duodenum, jejunum and ileum of broiler and layer chicks demonstrated faster digestive tract development in broilers relative to layers. The fasting period caused morphological changes in the liver and small and large intestines in both strains. Therefore, it must be highlighted that in studies involving organ weights and intestinal morphometrics, birds must not be submitted to fasting before tissue collection.

Morphological changes of the intestinal mucosa of broilers and layers as affected by fasting before sample collection

The present study aimed at evaluating the histo-morphological changes resulting from different fasting periods before the collection of tissue samples in different segments of the small intestine (duodenum, jejunum and ileum) of 7-d-old male chicks of a broiler and a layer strain. A completely randomized experimental design in in a 2x7 factorial arrangement, being two strains with different growth rates (Ross 308 and HyLine® W36) and seven fasting periods (0, 2, 4, 6, 8, 10 and 12 hours ), with six replicates, totaling 84 birds. The comparison of the morphometrics of the duodenum, jejunum and ileum of broiler and layer chicks demonstrated faster digestive tract development in broilers relative to layers. The fasting period caused morphological changes in the liver and small and large intestines in both strains. Therefore, it must be highlighted that in studies involving organ weights and intestinal morphometrics, birds must not be submitted to fasting before tissue collection.(AU)

Probiosis: concepts and prospects

The use of probiotics in animal and human feeding has been a subject of increasing interest both for the academia and the industry, mostly due to their potential positive effects on health and profitability. However, the knowledge on the composition of bacterial gastrointestinal communities in humans and animals, as well as its respective nutritional requirements, is far from being elucidated. Due to the ban of the use of antibiotic growth promoters in animal feeds, there has been an increasing interest on the utilization of probiotics to improve animal intestinal health under commercial settings. However, the possibility of horizontal transference of antibiotic-resistant genes between probiotic bacteria and pathogenic species has become a concern of poultry farmers and consumers around the world. Innovative ideas have emerged, such as the addition of essential oils, spices, and other plant extracts to feeds of monogastric animals to promote intestinal health. These natural compounds are considered ecologically adequate and safe for feeding purposes. This new reality will probably change the direction of research and of the use of additives in poultry production.

Probiosis: concepts and prospects

The use of probiotics in animal and human feeding has been a subject of increasing interest both for the academia and the industry, mostly due to their potential positive effects on health and profitability. However, the knowledge on the composition of bacterial gastrointestinal communities in humans and animals, as well as its respective nutritional requirements, is far from being elucidated. Due to the ban of the use of antibiotic growth promoters in animal feeds, there has been an increasing interest on the utilization of probiotics to improve animal intestinal health under commercial settings. However, the possibility of horizontal transference of antibiotic-resistant genes between probiotic bacteria and pathogenic species has become a concern of poultry farmers and consumers around the world. Innovative ideas have emerged, such as the addition of essential oils, spices, and other plant extracts to feeds of monogastric animals to promote intestinal health. These natural compounds are considered ecologically adequate and safe for feeding purposes. This new reality will probably change the direction of research and of the use of additives in poultry production.

The importance of endogenous nutrition of chicks from divergent strains for growing tested by deutectomy

Effects of yolk sac removal (deutectomy) upon performance of chicks from three divergent strains were tested to evaluate the importance of endogenous nutrition on the post-hatch phase. Chicks from three different strains (Hy-Line W98, Cobb 500, and JA57) were submitted to a surgery procedure after hatching. Half of them had the residual yolk removed, and the other constituted a sham-deutectomized group. After operation, chicks were designated to a 3 x 2 factorial design (3 strains x 2 presence/absence of yolk sac), in a total of six experimental groups and ten replications of two to four birds. During 14 experimental days all birds were fed ad libitum a 21% CP and 3050 kcal/kg EM mash diet. Data were analyzed by ANOVA, and Tukey's test (p 0.05). Relative yolk sac weights were similar among chicks from different breeders, averaging 11.7% to 13.5%. Comparing to sham-operated, deuctetomized chicks had lower weight gain at 7 and 14d, indicating that endogenous nutrition, via yolk sac, is very important to galliform birds whatever their strain. Hy-line deutectomized chicks gained 40% less body weight at the 7th day as compared to their sham counterparts. Analysis of the same criterion to Cobb and JA57 groups revealed a decrease of 16.1% and 10.8%, respectively, on weight gain efficiency. At the 14th rearing day, Hy-Line chicks had the lowest weight gain, followed by JA57s' and Cobbs'. The results suggested that chicks selected for fast growth are less dependent on endogenous nutrition, responding better when exogenous nutrition is associated to yolk assimilation.

Productive consequences of fasting neonatal chicks of different genetic constitutions for growing

The study was designed to evaluate the productive consequences of fasting neonatal chicks obtained from strains genetically divergent for growing. Four hundred eight chicks from three strains, 160 from breeders selected for high growth rate and excellent feed conversion ratio (Cobb 500), 160 from breeders not selected for fast growth (JA57), and 160 from a white egg layer strain (Hy-Line W98) were allotted in a 3 (strain) x 2 (fasting period - 8 and 36h after hatching) factorial arrangement with 5 replicates of 16 chicks each. Immediately after hatching, all chicks had similar (P>0.05) relative yolk sac weights (14.13%, 14.50%, and 15.49% for Hy-Line, Cobb, and JA57, respectively). The yolk sac retractions were proportionally higher for Cobb and JA57 chicks up to 144 h (6 days) after placement, but were not influenced by 36h of feed fasting. At 7 and 14 days of age only Cobb chicks had their body weight and weight gain significantly (P 0.05) depressed by 36h feed fasting after hatching. Results indicate that broiler chicks with intense initial growth rates (Cobb 500) need an outstanding nutritional supply, either from exogenous (feed) or endogenous (residual yolk) sources, to achieve a final weight compatible with their genetic constitution. For slow-growing chicks (Hy-Line), nutritional supplementation via yolk sac seems to be more important than exogenous supply (feed) of nutrients during the neonatal period.

Productive consequences of fasting neonatal chicks of different genetic constitutions for growing

The study was designed to evaluate the productive consequences of fasting neonatal chicks obtained from strains genetically divergent for growing. Four hundred eight chicks from three strains, 160 from breeders selected for high growth rate and excellent feed conversion ratio (Cobb 500), 160 from breeders not selected for fast growth (JA57), and 160 from a white egg layer strain (Hy-Line W98) were allotted in a 3 (strain) x 2 (fasting period - 8 and 36h after hatching) factorial arrangement with 5 replicates of 16 chicks each. Immediately after hatching, all chicks had similar (P>0.05) relative yolk sac weights (14.13%, 14.50%, and 15.49% for Hy-Line, Cobb, and JA57, respectively). The yolk sac retractions were proportionally higher for Cobb and JA57 chicks up to 144 h (6 days) after placement, but were not influenced by 36h of feed fasting. At 7 and 14 days of age only Cobb chicks had their body weight and weight gain significantly (P 0.05) depressed by 36h feed fasting after hatching. Results indicate that broiler chicks with intense initial growth rates (Cobb 500) need an outstanding nutritional supply, either from exogenous (feed) or endogenous (residual yolk) sources, to achieve a final weight compatible with their genetic constitution. For slow-growing chicks (Hy-Line), nutritional supplementation via yolk sac seems to be more important than exogenous supply (feed) of nutrients during the neonatal period.

The importance of endogenous nutrition of chicks from divergent strains for growing tested by deutectomy

Effects of yolk sac removal (deutectomy) upon performance of chicks from three divergent strains were tested to evaluate the importance of endogenous nutrition on the post-hatch phase. Chicks from three different strains (Hy-Line W98, Cobb 500, and JA57) were submitted to a surgery procedure after hatching. Half of them had the residual yolk removed, and the other constituted a sham-deutectomized group. After operation, chicks were designated to a 3 x 2 factorial design (3 strains x 2 presence/absence of yolk sac), in a total of six experimental groups and ten replications of two to four birds. During 14 experimental days all birds were fed ad libitum a 21% CP and 3050 kcal/kg EM mash diet. Data were analyzed by ANOVA, and Tukey's test (p 0.05). Relative yolk sac weights were similar among chicks from different breeders, averaging 11.7% to 13.5%. Comparing to sham-operated, deuctetomized chicks had lower weight gain at 7 and 14d, indicating that endogenous nutrition, via yolk sac, is very important to galliform birds whatever their strain. Hy-line deutectomized chicks gained 40% less body weight at the 7th day as compared to their sham counterparts. Analysis of the same criterion to Cobb and JA57 groups revealed a decrease of 16.1% and 10.8%, respectively, on weight gain efficiency. At the 14th rearing day, Hy-Line chicks had the lowest weight gain, followed by JA57s' and Cobbs'. The results suggested that chicks selected for fast growth are less dependent on endogenous nutrition, responding better when exogenous nutrition is associated to yolk assimilation.

Egg traits and physiological neonatal chick parameters from broiler breeder at different ages

This investigation was carried out to study egg traits (weight, specific gravity and eggshell thickness), and neonatal chick parameters (weight, blood, cardiac and lung parameters) from breeder at different ages. After hatching, neonatal chicks, male and female, from broiler breeder at three different ages (30, 45 and 60 weeks) were sacrificed and blood (red blood cell number, hematocrit, mean cell volume, blood viscosity, and haemoglobin), cardiac (right ventricle and total ventricle weights, cardiac index) and lung (mean pulmonary pressure, fresh relative lung weight) parameters were measured. No significant differences in eggshell thickness or specific gravity were observed in eggs from the three different breeder age. The incubated eggs and neonatal chicks showed heavier absolute weights with increasing breeder age. Broiler breeder age did not affect blood parameters or cardiac index, but affected right ventricle and total ventricle absolute weights. Red blood cell number and hematocrit were higher and lung weight and lung weight:chick weight index were lower for female neonatal chicks. The findings of this study revealed that breeder age affects neonatal chick parameters such as body weight, heart and lung absolute weights, but not blood parameters.

Egg traits and physiological neonatal chick parameters from broiler breeder at different ages

This investigation was carried out to study egg traits (weight, specific gravity and eggshell thickness), and neonatal chick parameters (weight, blood, cardiac and lung parameters) from breeder at different ages. After hatching, neonatal chicks, male and female, from broiler breeder at three different ages (30, 45 and 60 weeks) were sacrificed and blood (red blood cell number, hematocrit, mean cell volume, blood viscosity, and haemoglobin), cardiac (right ventricle and total ventricle weights, cardiac index) and lung (mean pulmonary pressure, fresh relative lung weight) parameters were measured. No significant differences in eggshell thickness or specific gravity were observed in eggs from the three different breeder age. The incubated eggs and neonatal chicks showed heavier absolute weights with increasing breeder age. Broiler breeder age did not affect blood parameters or cardiac index, but affected right ventricle and total ventricle absolute weights. Red blood cell number and hematocrit were higher and lung weight and lung weight:chick weight index were lower for female neonatal chicks. The findings of this study revealed that breeder age affects neonatal chick parameters such as body weight, heart and lung absolute weights, but not blood parameters.

Incubabilidade e Qualidade de Pintos de Ovos Matrizes de Frangos de Corte Submetidos a Estresse de Temperatura

This trial was carried out in order to evaluate the effect in broiler embryos of cold or heat stress on the hatching characteristics, and on the quality of the newborn chicks. Three hundred eggs obtained from 42-week-old broiler breeders were distributed in three incubators maintained at a temperature of 37.8C, relative air humidity of 60%, and mechanically turned on every two hour. At 16 days of incubation (D16), the embryos were submitted to heat (40C) or cold (32C) stress for 5 hours in two of the three machines. The non-stressed embryos of the third incubator were used as control. The data were analyzed in a complete randomized design with 3 treatments. The hatchability and chicks quality, evaluated by the number of neonatal and viable chicks, body weight at birth, and legs and navel qualities, were not different (P>0.05) among the control and temperature-stressed groups. However, results revealed that the eggs exposed to cold or heat stress showed a longer (P 0.05) incubation period - 506.5h and 504.2h, respectively - than those kept at normal temperature - 496.3h - as a consequence of a delay on internal (7 and 6h) and external piping (13 and 12h). It can be concluded that the 5-hour cold or heat stress at D16 is not enough to damage the hatchability or the quality of the chicks, but increase total incubation period, denoting that even a brief period of variation on the normal incubation temperature at a critical period of development is enough to determine stress in broiler embryos.

O experimento foi conduzido para avaliar o efeito do estresse de temperatura sobre as características de incubabilidade e qualidade dos pintos nascidos. Trezentos ovos, obtidos de um lote de matrizes de frangos de corte com 42 semanas, foram distribuídos em três incubadoras, reguladas para manter uma temperatura de 37,8ºC, umidade relativa de 60% e viragem mecânica a cada duas horas. Aos 16 dias de incubação (D16), aplicou-se uma variação de temperatura de calor (40ºC) ou frio (32ºC) durante cinco horas em duas máquinas. Os embriões da terceira máquina foram usados como controle. Os dados obtidos foram analisados estatisticamente, obedecendo-se a um delineamento inteiramente casualizado, com 3 tratamentos. A eclodibilidade e a qualidade dos pintainhos, avaliados pelo peso ao nascer e qualidade de pernas e umbigo não foram significativamente diferentes entre o grupo controle e os grupos estressados. Os resultados revelaram que os ovos exposto ao estresse pelo frio ou calor tiveram um período de incubação maiores - 506,5h e 504,2h, respectivamente - do que aqueles expostos a temperatura normal - 496,3h - como conseqüência no atraso de bicagem interna (7 e 6 h) e externa (13 e 14 h). Concluiu-se que a alteração da temperatura normal de incubação, com resfriamento ou aquecimento por 5 h no D16, não foi suficiente para prejudicar a eclodibilidade e a qualidade dos pintainhos, mas causou uma dilatação do período total de incubação, indicando que mesmo um breve período de variação da temperatura normal de incubação em um período crítico de desenvolvimento é suficiente para determinar estresse nos embriões de frangos de corte.

Incubabilidade e Qualidade de Pintos de Ovos Matrizes de Frangos de Corte Submetidos a Estresse de Temperatura

This trial was carried out in order to evaluate the effect in broiler embryos of cold or heat stress on the hatching characteristics, and on the quality of the newborn chicks. Three hundred eggs obtained from 42-week-old broiler breeders were distributed in three incubators maintained at a temperature of 37.8C, relative air humidity of 60%, and mechanically turned on every two hour. At 16 days of incubation (D16), the embryos were submitted to heat (40C) or cold (32C) stress for 5 hours in two of the three machines. The non-stressed embryos of the third incubator were used as control. The data were analyzed in a complete randomized design with 3 treatments. The hatchability and chick’s quality, evaluated by the number of neonatal and viable chicks, body weight at birth, and legs and navel qualities, were not different (P>0.05) among the control and temperature-stressed groups. However, results revealed that the eggs exposed to cold or heat stress showed a longer (P 0.05) incubation period - 506.5h and 504.2h, respectively - than those kept at normal temperature - 496.3h - as a consequence of a delay on internal (7 and 6h) and external piping (13 and 12h). It can be concluded that the 5-hour cold or heat stress at D16 is not enough to damage the hatchability or the quality of the chicks, but increase total incubation period, denoting that even a brief period of variation on the normal incubation temperature at a critical period of development is enough to determine stress in broiler embryos.

O experimento foi conduzido para avaliar o efeito do estresse de temperatura sobre as características de incubabilidade e qualidade dos pintos nascidos. Trezentos ovos, obtidos de um lote de matrizes de frangos de corte com 42 semanas, foram distribuídos em três incubadoras, reguladas para manter uma temperatura de 37,8ºC, umidade relativa de 60% e viragem mecânica a cada duas horas. Aos 16 dias de incubação (D16), aplicou-se uma variação de temperatura de calor (40ºC) ou frio (32ºC) durante cinco horas em duas máquinas. Os embriões da terceira máquina foram usados como controle. Os dados obtidos foram analisados estatisticamente, obedecendo-se a um delineamento inteiramente casualizado, com 3 tratamentos. A eclodibilidade e a qualidade dos pintainhos, avaliados pelo peso ao nascer e qualidade de pernas e umbigo não foram significativamente diferentes entre o grupo controle e os grupos estressados. Os resultados revelaram que os ovos exposto ao estresse pelo frio ou calor tiveram um período de incubação maiores - 506,5h e 504,2h, respectivamente - do que aqueles expostos a temperatura normal - 496,3h - como conseqüência no atraso de bicagem interna (7 e 6 h) e externa (13 e 14 h). Concluiu-se que a alteração da temperatura normal de incubação, com resfriamento ou aquecimento por 5 h no D16, não foi suficiente para prejudicar a eclodibilidade e a qualidade dos pintainhos, mas causou uma dilatação do período total de incubação, indicando que mesmo um breve período de variação da temperatura normal de incubação em um período crítico de desenvolvimento é suficiente para determinar estresse nos embriões de frangos de corte.