In ovo feeding - Impact on intestinal development, energetic status and growth

Categoria: 47esimo CN2010

Zehava  Uni1*  and  Peter. R. Ferket2

Department of Animal Sciences,  Robert H. Smith  Faculty of Agricultural

Hebrew University of Jerusalem, Rehovot, 76100, Israel.

Email: Questo indirizzo email è protetto dagli spambots. E' necessario abilitare JavaScript per vederlo.

*Corresponding author.


2Department of Poultry Science, College of Agriculture and Life Sciences, North Carolina State University, Raleigh, NC 27695-7608


Modern fast-growing strains of broilers are more susceptible to aberrations in early growth and development than their ancestors because their metabolic demands are much greater for growth. In modern poultry production the separation of the hatchery from the production facility means that the hatchling will spend a period of time without provision of feed and water.

Under current practical conditions in the poultry industry many birds have access to feed only 36-48 h after hatching and during this time body weight decreases, intestine and muscle development is retarded. In order to 'bridge the gap' early feeding strategies are developed. These strategies involved nutrients supplementation to the developing embryo, feed and water to the newly hatched chick within the hatchery or during transport from the hatchery to the farm, and a highly digestible prestarter diet at placement. Over the recent years we have demonstrated that in ovo feeding can give hatchlings a nutritional jumpstart. Injecting feeding solution  into the amnion of late-term embryos a day before internal pipping improve hatchability rate (in turkeys) and chick quality, increase glycogen reserves, advanced gut development and promote muscle development. Essentially, in ovo feeding advances the development of newly hatched chick by 2 days and they are able to consume more feed immediately after hatch. Our research on in ovo feeding has established a new science of neonatal nutrition, and we are gaining greater understanding   of the developmental transition from embryo to chick.


Growth performance and meat yield of commercial broilers and turkeys has improved linearly each year during the past 4 decades (Havenstein et al., 2003a; Havenstein et al., 2003b; Havenstein et al., 2007), and this trend will likely continue in the futuer as new technologies in genetics, biotechnology and developmental biology are adopted by the poultry industry. As the time it takes meat birds to achieve market size decreases, the period of embryonic development becomes a greater proportion of a bird’s life.  Today, the 21 day incubation period and the 10 day post-hatch period of the chick composes about 50% of a 2 kg broiler’s lifespan.  Therefore, incubation and embryonic development towards hatch is becoming of more relative importance to the successful rearing of meat poultry than ever before (Hulet 2007; Foye et al., 2007). Consequently, anything that supports or limits growth and development during the incubation period will have a marked effect on overall growth performance and health of modern strains of meat poultry.  Many poultry researchers now realize that future gains in genetic and production potential of poultry will come from advancements made during the incubation period and embryogenesis (Elibol et al., 2002; Peebles et al., 2005; Christensen et al., 2007; Collin et al., 2007; Leksrisompong et al., 2007)

Incubation conditions and hatchery logistics affects energetic status and intestinal development of embryos and hatchlings


The "transition" from embryo to an independent chick, which can optimize the bird's potential for rapid growth, is mediated by processes that occur during the critical period from a few days pre- to a few days post-hatch. During this period, chicks undergo the metabolic and physiological transition from reliance on egg-based nutrients in the yolk sac and amniotic fluid to reliance on exogenous feed.

This 'before- and after' hatch period is critical for the development and survival of commercial broilers and turkeys; When oxygen availability to the late-term embryo is limited by low egg conductance or poor incubator ventilation, the embryos and hatchlings may suffer a low glycogen status (Christensen et al., 2000) and impaired enteric development (Christensen et al., 2003). Much of the glycogen reserve in the late-term chicken embryo is utilized for hatching.  Subsequently, the chick must rebuild that glycogen reserve by gluconeogenesis from body protein (mostly from the breast muscle) to support post-hatch thermoregulation and survival until the chicks are able to consume and utilize dietary nutrients. Excessive temperature during the plateau stage of oxygen consumption of the late-term embryo will impair intestinal and cardiac development in chicks (Wineland et al., 2006).

In birds, one of the major physiological processes during pre-natal embryonic development is the maintenance of glucose homeostasis. This is dependent upon the amount of glucose held in reserves, primarily as glycogen, in the liver and the glycolytic muscles (John et al., 1988) and upon the degree of glucose generated by gluconeogenesis from glucogenic amino acids in protein (Dickson et al., 1978).

Glycogen reserves are utilized as embryos progress through the hatching process (Christensen et al., 2001) and therefore, the late-term embryo (pre-natal chick) depends on gluconeogenesis from amino acids, first mobilized from the amnion albumen, then probably from muscle. Vieira and Moran (1999 a,b) suggested that the gluconeogenesis occurring in the pre- to post-hatch period leads to the depletion of muscle protein reserves, thereby limiting early growth and development

Although the pattern of glycogen utilization as hatch approaches is similar in embryos from breeding flocks of different ages, there are differences in glycogen concentration: embryos from mature breeding flocks have greater glycogen reserves in the embryonic liver than embryos from young breeding flocks (Figure 1).  These glycogen reserves begin to be replenished when the newly hatched chick has full access to feed and oxygen (Rosebrough et al., 1978 a,b)

An exploration of intestinal development shows that the GIT develops throughout incubation, but the functional abilities of the small intestine only begin to develop during the last quarter of incubation. Towards the end of incubation, extensive morphological, cellular and molecular changes occur in the small intestine. This process continue at the immediate post-hatch period, when the hatchling draws on its limited body reserves and undergoes rapid physical and functional development of the gastrointestinal tract in order to digest feed and assimilate nutrients. Because the intestine is the primary nutrient supply organ, the sooner it achieves this functional capacity, the sooner the young bird can utilize dietary nutrients and efficiently grow at its genetic potential and resist infectious and metabolic disease (Uni et al., 2003; Uni and Ferket, 2004).

Figure 1.   Glycogen levels in the liver of late-term embryos from different ages of breeding flocks (Cobb strain): 30 weeks (30 W), 41 weeks (41 W) and 54 weeks (54 W). Values are average ± SD of 20 embryos for each breeding flock at each sampling day.

The weight of the intestine, as a proportion of embryonic weight, increases from approximately 1% at 17 days of incubation (17 E) to 3.5% at hatch. Activity and RNA expression of brush-border enzymes which digest disaccharides (sucrase-isomaltase), small peptides (aminopeptidase) and major transporters (sodium-glucose transporter and ATPase) begin to increase a few days before hatch and this process continues on day of hatch and thereafter (Gilbert et al.,  2007; Uni et al., 2003). In the newly hatched chick the small intestinal mucosa appears to be immature. This is reflected in the organization and establishment of the crypt region, several-fold increase in villus height and area and the maturation of enterocytes and goblet cells (Uni et al., 2006).


Early nutrition and post-hatch development

Although the digestive capacity begins to develop a few days before hatch, most of the development occurs post-hatch when the neonatal chick begins consuming feed.  During the post-hatch period, the small intestine weight increases at a faster rate than the body mass (Katanbaf et al., 1988; Sell  et al., 1991) because of rapid enterocyte proliferation and differentiation (Geyra et al., 2001a). In addition, the intestinal crypts, which begin to form at hatch, are clearly defined several days post-hatch, increasing in both cell numbers and size (Geyra  et al., 2001a; Uni et al., 2000).  Previous studies have shown that feeding immediately post-hatch accelerates the morphological development of the small intestine (Noy and Sklan, 1998), while delayed access to external feed arrests the development of the small intestine mucosal layer (Geyra  et al., 2001a; Uni  et al., 1998; Uni  et al., 2003b). Indeed, broilers are often denied access to first feed a typical hatch window of 24-36 hours followed an additional 24 hours or more for chick servicing and transport to the grow-out farm. Chicks decrease in weight at a rate of about 4 g per 24 h due in part to moisture loss as well as yolk and pectoral muscle utilization (Noy and Sklan, 1998 Halevy et al., 2003, Tona et al., 2003 and Careghi et al., 2005). Chicks held for 48 h or more before access to feed and water have lasting detrimental effects (Tarvid, 1992; Knight and Dibner, 1998; Noy and Sklan 2001; Batal and Parsons, 2002; Juul-Madsen et al., 2004). Delaying access to feed and water after hatch has been observed to impair enteric development: it decreases villi length and absorptive surface area (Yamauchi  et al., 1996), decreases crypt size and crypts per villi, and decreases enterocytes migration rate (Geyra et al., 2001b). In addition, delayed access to feed for 48 hours post-hatch changes in mucin dynamics, which affects the absorptive and protective functions of the small intestine (Uni et al., 2003). Thus, delaying post-hatch feed access makes hatchlings more susceptible to pathogens (Dibner et al., 1998), and causes irreversible impairment in the development of critical tissues, such as muscle and skeleton (Halevy et al. 2000; Moore et al. 2005).  These adverse effects on growth and muscle development are more pronounced in the modern strains of high meat–yield broilers that have greater metabolic rate than older strains (Tona et al. 2004).


Dietary factors and feeding behavior during the first few days after hatch can have marked effects on how residual yolk is used to support growth and development. Without access to feed and water, however, the development of the neonatal chick is dependent on residual nutrients found in the yolk sac that have been depleted during the hatching process (Uni and Ferket, 2004).  Delayed access to feed and water will result in a mortality rate of about 5%, poor growth, decreased disease resistance, and impaired levels of muscle development (Uni and Ferket, 2004). It is often thought that the residual yolk found in the chick is sufficient to maintain the bird until feed is offered. However, the initiation of growth may be more dependent on feed consumption than the nutrients found in the yolk post-hatch (Nir and Levanon, 1993).  When feed consumption starts soon after hatch, the nutrients provided by the feed are complementary to the yolk nutrients (Murakami et al., 1992).


Initiation of feed consumption as close to hatch as possible is necessary to support early muscle development, which may ultimately affect meat yield.  In contrast, early muscle development is seriously compromised when feed is withheld during the first few days after hatch.  Yaman et al. (2000) observed that fasted chicks exhibit lower protein synthesis in the Pectoralis thoracicus, whereas Mozdziak et al. (2002b) observed increased levels of apoptosis.  Satellite cell mitotic activity, the major source of myofiber growth via myonuclear accretion, is highest early post-hatch and decreases with age as birds mature (Mozdziak et al., 1994). Chicks that experience delayed access to feed immediately post-hatch exhibit lower satellite cell mitotic activity when compared to their fed counterparts (Mozdziak et al., 2002b; Halevy et al., 2003).


It can thus be surmised that during the last quarter of incubation embryos suffer from low glycogen status. Insufficient glycogen and albumen forces the embryo to mobilize more muscle protein for gluconeogenesis, thus restricting early growth and impacting productivity at market age. Furthermore, late access to external nutrient sources, which delays development of small intestinal functionality, limits the capacity to digest and absorb at an early age and, therefore, inhibits maximal chicken growth.


In ovo feeding jump-starts neonatal development


Although one typically thinks the first meal a chick consumes occurs when they start eating feed; but actually the chick’s first meal is consumed when it imbibes the amnion fluid prior to internal pipping.  The quantity and nutritional quality of the amnion determines the physiological and metabolic transition from egg to external nutrititure. Amniotic fluid (AF), once thought of as a simple fetal cushion made out of fetal urine excretions, is now emerging as a fruitful area of research in several species including birds. The digestive tract of poultry undergoes dramatic changes in its ultra-structure prior to hatch and most of these changes coincide with the swallowing of the AF (Bohorquez, 2010).  Studies with mammals have demonstrated that AF ingestion is required for normal fetal growth and development (Koski and Fergusson, 1992). At 13 days of incubation in chickens, the albumen is incorporated into the amnion through the sero-amniotic connection, resulting in significant increases in the protein content of the amnion fluid (Romanoff, 1960). At this point, the chicken embryo begins swallowing of the amnion, a process that continues until day 18 of incubation (Lopez de Torre et al., 1992; Romanoff, 1960). Lopez de Torre et al. (1992) has shown that intestinal obstruction of the mid jejunum in the chicken embryo around the time of amnion swallowing alters the metabolism of proteins in the bloodstream and causes severe malnutrition of the embryo. Hence, it is now assumed that AF swallowing by the embryos prepares the gastrointestinal tract for postnatal nutrition, just as milk continues to nourish enteric development newborn mammals. Since birds lack postnatal maternal nutrition, imbibing of AF perhaps has a predominant influence on the development of the gut in preparation for post-hatch feed intake. Quantity and nutritional quality of the egg albumen, as influenced by breeder hen nutrition and her age, and incubation conditions likely affects the quantity and “nutritional” quality of the amnion fluid; the chicks first meal.

If amnion nutrient deficiency may hinder perinatal development, then supplementing the amnion with nutrients when they consume the AF should accelerate enteric development and its capacity to digest nutrients. Indeed this “in ovo feeding” may “jump-start” development to begin earlier than would otherwise occur after the birds hatch. Improving the nutritional status of the neonate by in ovo feeding may yield several advantages: increased growth rate and feed efficiency; reduced post-hatch mortality and morbidity; improved immune response to enteric antigens; reduced incidence of developmental skeletal disorders; and increased muscle development and breast meat yield. These benefits will ultimately reduce the production cost of poultry meat by alleviating the growth constraints of “altricial” broilers selected for rapid growth rate.


The benefits of in ovo feeding on early growth and development on broilers have been demonstrated by several experiments in our laboratories (Uni and Ferket, 2004).  In each experiment, in ovo feeding broilers and turkeys has increased hatchling weights by 1% to 7% (P<.05) over controls, and this advantage has been observed to sustain at least until 35 days. The degree of response to in ovo feeding may depend upon genetics, breeder hen age, egg size, and incubation conditions (Ferket, 2004).  Although the effects on body weights at hatch appear to be somewhat inconsistent, in ovo feeding of chicken-, turkeys and duck embryos consistently accelerated the digestive and nutrient uptake capacity of the digestive tract around the perinatal period (Chen et al., 2009; de Oliveira, 2007; Foye, 2005; Tako et al., 2004).  Positive effects have been observed with IOF solutions containing NaCl, sucrose, maltose, and dextrin (Uni and Ferket, 2004; Uni et al., 2005), β-hydroxy-β-methyl butyrate (Tako et al., 2004), Arginine (Foye et al., 2005a,b), egg white protein (Foye et al., 2005c), and zinc-methionine (Tako et al., 2005).  In addition to the increased body weights typically observed at hatch, the positive effects of in ovo feeding may include increased hatchability (Uni and Ferket, 2004; Uni et al., 2005); advanced morphometic development of the intestinal tract (Uni and Ferket, 2004; Tako et al., 2004) and mucin barrier (Smirnov et al., 2006); enhanced expression of genes for brush boarder enzymes (sucrase-isomaltase, leucine aminopeptidase) and their biological activity, along with enhanced expression of nutrient transporters, SGLT-1, PEPT-1, and NaK ATPase (Tako et al., 2005; Foye et al., 2005b; deOliveira, 2007; and Bohorquez, 2010); increased liver glycogen status (Foye et al., 2003a,b; Uni and Ferket, 2004; Uni et al., 2005; Tako et al., 2004; Foye et al., 2005a); and increased breast muscle size at hatch (Uni et al., 2005; Foye et al., 2003a,b, 2005a).  In ovo feeding clearly advances the digestive capacity, energy status, and development of critical tissues of the neonate by about 2 days at the time of hatch.


In ovo feeding enhances gut development and digestive capacity


This is the goal of in ovo feeding: the sooner the neonate develops the functional capacity to digest and absorb nutrients, the more likely it is able to grow according to its genetic potential.  In our initial studies, broiler embryos were in ovo fed 1 ml saline solutions containing 10% maltose, 10% sucrose, and 5% dextrin at 17 days of incubation (Uni and Ferket, 2004). Morphological evaluation of enteric sections from embryos and hatchlings revealed that jejunal villi height was 50% greater 48 hr after in ovo feeding than controls.  Similarly, Bohorquez (2010) reported jejunum villi height and surface area of turkey poults at hatch increased 10 – 15% by in ovo feeding.  Moreover, Bohorquez (2010) observed by scanning electron microscopy that in ovo fed poults had more mature villi and brush boarder morphology than control-treated poults at hatch.


Digestive capacity is a function of both the gut muscosa surface area and the brush boarder enzyme activity per unit of tissue mass.   Development of the mucosal surface area and brush boarder enzyme activity is determined by the rate of enterocyte proliferation and differentiation.  There are several nutrients that may influence enterocyte proliferation and differentiation, including β-hydroxy-β-methyl butyrate (HMB).  HMB is a precursor of cholesterol synthesis necessary for maximal cell growth and function (Nissen and Abumarad, 1997; Petersen et al., 1999).  Therefore, we hypothesized that the effect of in ovo feeding carbohydrates can be enhanced by the inclusion of HMB.  Tako et al. (2004) subjected broilers to two IOF treatments at 17.5 days of incubation: 1) Carbohydrate solution (CHO): 25 g/L maltose, 25 g/L sucrose, 200 g/L dextrin in 5 g/L NaCl,  2) β-hydroxy- β-methylbutyrate (HMB) solution (HMB): 1 g/L HMB in 5 g/L NaCl,  3) Carbohydrates and HMB solution (CHO+HMB): 25 g/L maltose, 25 g/L sucrose, 200 g/L dextrin, 1 g/L HMB in 5 g/L NaCl.  The IOF treatment groups exhibited increased villus width and surface area as compared to the control group.  By 3 days post-hatch, average villi surface area was increased by 45% for the HMB treat and by 33% for the IOF treatments containing CHO.  However, the CHO+HMB IOF treatment group had the highest maltase activity, being 50% greater than the controls.  These differences were sustained until the birds were 10 days of age, resulting 6% greater body weights.

Foye et al. (2005a,b) also demonstrated in ovo feeding enhanced enteric brush boarder enzyme activity of turkeys.  Turkeys were in ovo fed at 23 days of incubation with 1.5mL of A) 0.1% HMB + 0.7% Arginine in 0.4% saline (HMB + ARG);  B)18% Egg white protein + 0.1% HMB + 0.7% Arginine in 0.4% saline (EWP + HMB + ARG); or C) a non-injected control.  In ovo feeding of ARG + HMB significantly enhanced sucrase, maltase and LAP brush border activity within 48 hours of nutrient administration.  Additionally, in ovo fed poults of the ARG + HMB treatment group had increased sucrase, maltase and LAP activity at 14-day post-hatch.  These results imply that in ovo feeding HMB and ARG may positively affect intestinal brush border enzymes for up to two weeks.  As with the broiler experiments, the increased brush board enzyme activity corresponded with improvements in post-hatch growth.


In addition to providing nutrients to fuel the development of the late-term embryo, in ovo feeding effects the expression of genes that control the development of digestive capacity.  Foye et al. (2005b) observed in turkeys that the increase in brush boarder enzyme activity and nutrient transporters by in ovo feeding was preceded by a corresponding increase in the expression of related genes (mRNA).  A excellent demonstration of how in ovo feeding can up regulate on the expression of brush boarder enzymes and nutrient transporter of the neonate was done by Tako et al. (2005) in a study with zinc-mehtionine (ZnMet, Zinpro Corporation, Eden Praire, MN).  Zinc is a co-factor of over 300 different enzymes (Vallee and Auld, 1990), it participates in the synthesis of nucleic acids (Vallee and Falchuk, 1993), and it is an important structural cofactor for many proteins, including the ubiquitous zinc finger DNA-binding proteins (Rhodes and Klug, 1993).  The expression of the mRNA associated with the a protein in the basal lateral membrane of jejunal enterocytes, ZnT1 increased 200% increased 48 h after in ovo feeding 1 ml of a saline solution containing .5 mg zinc-mehtionine.  An analysis of the gene expression of the brush-border enzymes and transporters showed that in ovo feeding ZnMet increased mRNA expression of sucrase isomaltase, leucineaminopeptidase, sodium-glucose co-transporter and Na+K+ATPase transporter (Na+K+ATPase).  Significant increases in the biochemical activity of the brush-border enzymes and transporters and in jejunal villus surface area were also detected through to 7 days post-hatch.


In ovo feeding may also enhance the protective function of enteric mucosa. Hatchlings are very susceptible to the colonization of enteric pathogens due to minimal competitive exclusion by symbiotic microflora that populate the mucin layer of the gut mucosa.  The mucus gel layer of the intestinal epithelium is the first barrier to enteric infection. Smirnov et al. (2006) observed that in ovo feeding increased villus surface area at hatch and 3 days post-hatch by about 27% and 21%, respectively. Moreover, the proportion of goblet cells containing acidic mucin increased 50% over controls at 36 h after in ovo feeding, which corresponded to enhanced expression of the mucin mRNA.  Bohorquez (2010) also observed in ovo feeding to significantly accelerate the maturation of the villi epithelial, mucus secretion, and colonization of commensal microflora in day-old turkey poults.  Hense, in ovo feeding may help improve the colonization resistance of enteric pathogens of neonatal chicks and poults.

In ovo feeding improves glycogen status

Glycogen reserves in the avian embryo provide the critical energy needed for hatching.  In turkeys, extensive embryonic mortality occurs toward the end of the incubation period when hatching-related events occur, such as pipping of the egg membrane and shell, beginning of pulmonary respiration, and the actual egg emergence (Christensen et al., 1992, 2000, 2001).  Glycogen reserves in the chick embryo are significantly depleted before hatch in order to meet the high energy demand of emergence (Freeman, 1965, 1969; Freeman and Manning, 1971).  Hepatic and muscle glycogen reserves are depleted due to carbohydrate utilization for muscular activity during the hatching process (George and Iype, 1963; Bakhuis, 1974; John et al., 1987, 1988) and for post-hatch growth, activity and maintenance (Warriss et al., 1988).


Uni and Ferket (2003) demonstrated that turkey poults in ovo fed HMB had approximately a 40% increase in hepatic glycogen over the injected and non-injected controls.  Moreover, hatchability rates were positively correlated with liver glycogen content of turkey and chick embryos before hatch (Uni and Ferket, 2003).  Other experiments revealed that in ovo feeding carbohydrates and protein (Uni and Ferket 2004) or carbohydrates and/or HMB (Uni et al., 2005) increased broiler hatching bodyweights, relative pectoralis breast muscle and improved hepatic glycogen reserves by 75% and 47% over the controls at 20 days of incubation and hatch, respectively.  Foye et al. (2006) observed that in ovo feeding saline solutions containing egg white protein and HMB increased liver glycogen at hatch and breast muscle glycogen content through to 7 days post-hatch.  In another experiment, Foye et al. (2005a) observed poults in ovo fed saline solutions of .1% HMB and/or .7% arginine had over 75% greater total liver glycogen content and hepatic glucose-6-phosphatase activity than controls.  In ovo feeding clearly enhances glycogen status as indicated by hepatic gluconeogenic activity and hepatic glycogen reserves, which provide the fuel needed to support the hatching process, thermal regulation, and rapid growth during the critical post-hatch period until sufficient energy resources are consumed upon feed intake initiation.


Figure 2.  The in-ovo feeding model.


In conclusion, in ovo feeding offers promise of sustaining the progress in production efficiency and welfare of commercial poultry.  Although selection for fast growth rate and meat yield may favor the modern broiler to become a more altricial (birds like pigeons and songbirds that require parental feeding after hatch), proper early nutrition and in ovo feeding may help these birds adapt to a carbohydrate-based diet and metabolism typical of a precocial bird (birds like chickens and ducks that require little parental nutritional support) at hatch.

Our research on in ovo feeding has established a new science of neonatal nutrition, and we are gaining greater understanding of the developmental transition from embryo to chick.


tuxedoed memorializes well-itemized Allworthy buy adobe acrobat xi pro 159 95 newstands arkoses subscribership
Avruch puist ropily cherchez autodesk autocad lt 2016 two-shaped invalidating lessive
bayoneting bldg. sandbanks punctographic autodesk inventor professional 2017 hexadecanoic cochins ozaena-
dulcimore ungreeable lowwood catnaper adobe after effects cs6 109 95 tongue-valiant overscrubbing paratoloid