Embryonic thermal manipulation of poultry birds: Lucrative and deleterious effects

The major efforts to improve feed conversion, increase the body weight and breast muscle yield of broilers have been focused on feeding and management at the post hatch period. However, incubation temperature is the most significant factor for the egg hatching rate, chick quality, and post hatch performance. Therefore, incubation factors affecting the performance should be taken with necessary precautions. Incubation temperature not only affects the early development of the hatchlings but also has a lasting impact on the characteristics of the chicks, such as final body weight and meat quality traits. This article provides an overview about embryonic thermal manipulation (TM) of domestic fowls and review the lucrative and deleterious effects of embryonic TM on embryo development, muscle growth, thermotolerance acquisition, and immunity.

Embryonic thermal manipulation of Japanese quail: effects on embryonic development, hatchability, and post-hatch performance

Embryonic thermal manipulation led to several modifications in molecular, physiological, and biochemical parameters which affect pre- and post-hatch growth performance. The current study aims to elucidate the onset and long-term effects of intermittent thermal manipulations (TM) during two-time windows, early/late, of embryogenesis in Japanese quail (Coturnix japonica) on embryonic development, hatchability, muscle histogenesis, and post-hatch growth performance. Four groups were created; quail eggs in the control group were incubated at 37.7 °C and relative humidity (RH) 55%. Three thermally treated groups were incubated intermittently at 41 °C and 65% RH intermittently (3 h/day): early embryogenesis group (EE) was thermally treated during embryonic days (ED) 6-8, late embryogenesis group (LE) was thermally treated during (ED12-ED14), and early and late embryogenesis group (EL) was thermally manipulated in both time windows. Relative embryo weights in EL and EE were significantly lighter than those in LE and Ctrl groups. The hatched chicks were reared under optimal managemental conditions (three replicates per treatment). Average daily feed intake was recorded, and feed conversion ratio (FCR) was calculated. Histological and quantitative analyses of muscle fibers were performed. The results revealed that TM led to significant hypertrophy of quail breast muscle in (EE). Intermittent short-term (3-6 h) thermal manipulation (39-40 °C) protocols during early embryogenesis (ED6-ED8) could be recommended to enhance muscle mass growth and breast muscle yield in the Japanese quail.

Production and growth related disorders and other metabolic diseases of poultry – A review

In humans, metabolic complaints may be associated with a failure in one of the body hormone or enzyme systems, a storage disease related to lack of metabolism of secretory products because of the lack of production of a specific enzyme, or the breakdown or reduced activity of some metabolic function. Some of these disorders also occur in poultry, as do other important conditions such as those associated with increased metabolism, rapid growth or high egg production that result in the failure of a body system because of the increased work-load on an organ or system. These make up the largest group of poultry diseases classified as metabolic disorders and cause more economic loss than infectious agents. Poultry metabolic diseases occur primarily in two body systems: (1) cardiovascular ailments, which in broiler chickens and turkeys are responsible for a major portion of the flock mortality; (2) musculoskeletal disorders, which account for less mortality, but in broilers and turkeys slow down growth (thereby reducing profit), and cause lameness, which remains a major welfare concern. In addition, conditions such as osteoporosis and hypocalcaemia in table-egg chickens reduce egg production and can kill.

Effect of short periods of high incubation temperature on hatchability and incidence of embryo pathology of turkey eggs

1. Turkey eggs were incubated at 38.0 degrees and 38.5 degrees C at different stages of embryo development and for periods of 3 to 25 d. Results were compared with control eggs incubated at 37.5 degrees C. The age of mortality, the incidence of malpositions and the incidence of morphological abnormalities were recorded from all unhatched eggs. 2. Eggs incubated at 38.5 degrees C for 5 or more days hatched significantly less well than eggs incubated at 37.5 degrees C. Eggs incubated at 38.5 degrees C for 3 d hatched worse than controls but not significantly so. Eggs incubated between 0 and 25 d and 7 and 12 d but not between 0 and 6, 13 and 18 and 19 and 25 d, at 38.0 degrees C had significantly lower hatchabilities than eggs incubated at 37.5 degrees C. 3. Lowest hatchabilities were obtained when the eggs were incubated at high temperatures between 7 to 12 d and 6 to 10 d, indicating that embryos at this stage of development are more likely to succumb to high temperature than at other ages. 4. Increases in embryo mortality due to overheating were seen in weeks 3 and 4 of incubation and at the pipping stage. This was observed even when the period of overheating occurred in weeks 1 and 2 of incubation. 5. Embryos malpositioned with their head in the small end of the egg were seen at a higher incidence when overheating in the 2nd or 3rd quarter of the incubation period.

JCV, Loddi MM, Takita TS. Incubabilidade e Qualidade de Pintos de Ovos Matrizes de Frangos de Corte Submetidos a Estresse de Temperatura

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.

Response of layer breeders to dietary acetylsalicylic acid. 3. Effects on fertility and hatchability of embryos exposed to control and elevated incubation temperatures

Because acetylsalicylic acid (ASA, aspirin) is a common antipyretic drug, there has been considerable research on the effects of ASA on mammalian embryonic development. However, very limited research has been conducted on the effects of ASA on avian development and hatchability. The present study investigated the effect of dietary ASA on fertility and hatchability and whether embryos of breeder hens fed ASA, as compared with embryos of hens fed a control diet, would survive elevated temperatures during incubation. White Leghorn layer breeders were fed 0, .025, .050, .100, .200, and .400% ASA for the first 13 mo of egg production. When averaged over 13 mo, hens fed .40% dietary ASA demonstrated a decline in fertility (P < .03), hatchability of fertile eggs (P < .04), and hatchability of eggs set (P < .02). Chicks from hens fed .10% ASA weighed more than chicks from hens receiving 0, .025, .20, or .40% ASA (P < .01). When embryos were incubated at elevated temperatures of 42.8 or 43.3 C for 5.5 to 12 h on Day 16 of incubation, hatchability declined. Also, ASA fed to layer breeders did not improve hatchability of embryos exposed to elevated incubation temperatures when compared with embryos exposed to a control incubation temperature (37.2 C). During Month 9 of production, chicks from hens fed .05 and .10% ASA and exposed to an elevated temperature of 42.8 C for 9 h on Day 16 of incubation weighed more than similarly heat-stressed chicks of hens fed 0, .20, or .40% ASA (temperature by diet interaction, P < .03).(ABSTRACT TRUNCATED AT 250 WORDS)

Science and the art of incubation

The artificial incubation of eggs of domesticated species can now be carried out with a high degree of success. However, advances in understanding about the problems faced by the developing embryo during incubation are still being made; and some may help "fine-tune" the incubation process. This paper deals particularly with the use of egg-cooling during incubation as a means of manipulating takeoff times, the use of water-vapor conductance monitoring by weight to predict the optimal humidity conditions for batches of eggs from different strains and species, cuticle-stripping to improve embryonic respiratory gas exchange, and some aspects of egg hygiene. Problems with hatchability usually can be traced to factors such as infertility, faulty breeder nutrition, disease status, or poor egg handling and hygiene, rather than to faulty incubation technique per se. Outlined here are the steps taken to solve an interesting but serious hatchability problem, the cause of which was traced to the presence of kapok seed meal in the breeder diet.