The Potential of In Ovo Feeding and Perinatal Nutrition

Modern agriculture constantly strives to maximize biological performance of food production in an effort to optimize economic efficiency, profit potential, and sustainability. Commercial poultry production is among the most efficient and progressively successful of all food production sectors. What factors does it take for continued success in efficient poultry production? It takes the right genetics, combined with optimum health and management practices, and an optimized nutrition and feeding program. Efficiency and sustainability depends on the ability of a poultry production company to achieve competitive production indicators, including average daily gain, days to market weight, feed (caloric) conversion, livability, flock uniformity, and processing yields. However, profitability largely depends on how well a poultry production company meets consumer demand. Consumers want wholesome, safe, and affordable food. They want poultry products that look good, and are enjoyable to eat. In addition, the more affluent consumers also want to buy their food from companies that excel in environmental stewardship and animal welfare. After proper management of commercial genetic stock, nutrition and feed is the most variable component of economic efficiency and profitability, as it represents 70 to 80% of live production costs.

Genetic selection is continually changing the “playing field” of production potential for the poultry industry; but it is the expression of this genetic potential that will drive performance and profitability. Growth performance and meat yield has improved linearly by about 1% each year, and 85% of this improvement is attributed to genetic selection of broilers (Havenstein et al., 2003) and turkeys (Havenstein et al., 2007). Nutritional advancements have not kept pace with genetic selection. However, the time has come to close this pace gap as we learn to harness the power of nutritional imprinting and adaptive conditioning to program the genes the geneticists has helped to assemble based on Mendelian genetics.

The ancient Greek philosopher, Aristotle, theorized an individual’s traits are acquired from their parents and contact with their environment. In simple terms, Aristotle’s theory of developmental destiny means that all life on this planet is programmed to succeed in its given environment! Just a generation before Mendel’s time, Jean Lamark was a proponent of the inheritance of acquired characteristics. The so called Lamarckism theory emphasized the use and disuse of organs as the significant factor in determining the characteristics of an individual, and it postulates that any alterations in the individual could be transmitted to the offspring through the gametes. Despite many attempts, this inheritance of acquired characteristics has never been experimentally verified. Furthermore, many of Lamarck’s examples, such as the long neck of the giraffe, can be more satisfactorily explained by means of natural selection.

The academic discipline of genetics has followed Mendel’s basic concepts for over a century, and it was reinforced by the discovery and sequencing of DNA. Genetics describes the inheritance of information on the basis of DNA sequence. As the DNA sequence fragments were scientifically associated with certain biological traits, genomic scientists began to realize the importance of the gene expression. It was not until the recent introduction of molecular biological tools that the science of Epigenetics and conditional imprinting has emerged. We can now study gene expression by mRNA up-regulation, proteomics and metabolonics. Now, many molecular geneticists agree that gene expression in response to environmental cues can be passed on to future generations. The old Greek philosophers and Jean Larmarck may have been right after all; they just did not have the scientific tools to prove it! There is now growing evidence that nutrition and environmental stimuli of breeding stock and their progeny during the perinatal period may literally program how an animal’s genes are expressed as an adaptive response to increase the chances of survival. This new science of “gene expression programming” is Epigenetics; it is the inheritance of information on the basis of gene expression, or inherited adaptation.

What is Epigenetic or Adaptive Conditioning?

I am the son of Dutch immigrants who came to Canada in 1956 to farm as my ancestors did before them. My parents left the Netherlands so their children would not experience what they had experienced when they were children during World War II. They occasionally spoke of how the Nazi soldiers took nearly all the food their family farm produced, leaving barely enough of the food they toiled to produce to eat for themselves. Towards the end of World War II there was a national famine that caused over 30,000 people to starve to death because of a Nazi-imposed food embargo, scarce food supplies because of war-torn agricultural lands, and an unusually harsh winter. Detailed birth records collected during that “Dutch Winter Famine” provided scientists with useful data for analyzing the long-term health effects of prenatal exposure to famine. The children of this famine to 3 generations have unusually high incidence of developmental and adult disorders, including low birth weight, short body height, diabetes, obesity, coronary heart disease, and cancer, (Pray, 2004). In another study, Kaati et al. (2002) correlated grandparent’s prepubertal access to food with diabetes and heart disease. Remarkably, a pregnant mother’s diet can affect the expression of her genes in such a way that not only her children, but her grandchildren and possibly great-grandchildren inherit the same health problems. Using data from a small Swedish community, Pembrey et al. (2006) observed that epigenetic effects are sex-linked. Grandfathers who had access to surplus food during their slow growth phase (9 to 12 years of age) begot more diabetic grandsons than grandfathers who did not have as much food available to them before they reached puberty. In contrast, the biggest effect of food supply in grandmothers occurred when she was a fetus and infant, and it affected the mortality rate of their granddaughters. These responses suggest that information is being captured at key stages of egg and sperm formation, and is passed on to the offspring,
possibly in form of epigenetic patterns.

Epigenetics literally means “on genes”, and refers to all modifications to genes other than changes in the DNA sequence itself. DNA within each cell is wrapped around proteins called histones. Both the DNA and histones are covered with chemical tags, to form what is called the epigenome. These chemical tags react to signals to the outside world, such as diet and stress. Some parts of the epigenome are wrapped and unreadable, and other parts are relaxed and readable for expression. A good instructional video that describes the basic concepts of epigenetics can be viewed at http://learn.genetics.utah.edu/content/epigenetics/intro/.

Epigenetic imprinting of genes occurs most often by differential methylation of DNA at the promoter regions of specific genes that can permanently modulate an organism’s adaptive response to adverse stimuli during critical periods of development. Particularly, early-life programming can turn on “Thrifty” genes that permanently reprogram normal physiological responses to survive environmental stressors,  including moderate nutrient deficiency, and thus increase the chances of passing on their genes to the next generation. Evidence for epigenetic programming is demonstrated by swarming locusts: the swarming phenotype is environmentally influenced by drought conditions and the trait is passed onto the next generation until the population finds better conditions. 

Transgenerational epigenetic or adaptive conditioning may explain some of the blessings and curses observed as a result of our system of commercial poultry production. Consider how we manage the weight of broiler or turkey breeders before and during egg production: this is during the critical epigenetic period of gametogenesis. Broiler breeder nutrition and feeding management likely has an important epigenetic effect on progeny. Consider how we manage and incubate commercial hatching eggs: this is during the critical epigenetic period of de novo methylation of somatic cells in the embryo. Environmental conditions (i.e. temperature and oxygen concentration) in the incubator may program epigenetic responses that affect subsequent metabolism. Consider how we manage chicks during the first few days after hatch. Feeding behavior, nutrition, and brooding conditions can affect metabolism and the development of breast muscle, the skeleton, and immune system.


In Ovo Feeding Jump-Starts Perinatal Development

Phenotypic characteristics that are programmed or imprinted to succeed in it’s given environment and diet happen most effectively when the animal is young, and it is the first few meals that usually make the difference. For example, all honeybees are genetically similar, but what predestines a bee to become a worker or a queen is what the larvae are fed. Likewise, poultry can be programmed to succeed with the desired phenotypic traits by modifying nutritional modification during the perinatal period: the first 3 days before and after hatch. The chick’s first meal occurs when it imbibes the amnion prior to hatch, and so this is the first opportunity for nutritional programming. By in ovo feeding (Uni and Ferket, 2003; US Patent No. 6,5692,878), nutrient balance and key metabolic co-factors of the amnion meal can be modified and influence subsequent phenotypic traits of economic importance for the poultry industry.

The benefits of in ovo feeding on early growth and development of broilers and turkeys have been demonstrated by several experiments in our laboratory (Uni and Ferket, 2004). In ovo feeding has increased hatchling weights by 3% to 7% (P<.05) over controls, and this advantage is often sustained at least until 14 days post-hatch. The degree of response to in ovo feeding may depend upon genetics, breeder hen age, egg size, and incubation conditions (i.e. the epigenotype). Above all, IOF solution formulation has the most profound effect on the neonate. 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, egg white protein, and carbohydrate (Foye et al., 2006ab), Arginine (Foye et al., 2007), 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 activities, along with enhanced expression of nutrient transporters, SGLT-1, PEPT-1, and NaK ATPase (Tako et al., 2005; Foye et al., 2007); increased liver glycogen status (Uni and Ferket, 2004; Uni et al., 2005; Tako et al., 2004; Foye et al., 2006a); enhanced feed intake initiation behavior (de Oliveira, 2007); and increased breast muscle size at hatch (Uni et al., 2005; Foye et al., 2006a). 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. Using scanning electron microscopy, Bohórquez et al. (2008) observed that in ovo feeding significantly increased functional maturity and mucus secretion of goblet cells of villi of ileum and ceca of turkey poults. Associated with these goblet cells was the colonization of lactobacilli. Therefore, in ovo feeding may help improve the colonization resistance of enteric pathogens of neonatal chicks and poults. 

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, proper early nutrition and in ovo feeding may help these birds adapt to a carbohydrate-based diet and metabolism typical of a precocial bird 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. However, much more work must be done before in ovo feeding can be adopted for commercial practice.

The first few days post-hatch is the second part of the perinatal period that can imprint production traits by adaptive conditioning of gene expression. Chicks can be imprinted to enhance their tolerance to immunological, environmental, or oxidative stress. Nutritional programming during the perinatal period can also influence energy and mineral utilization or requirement, while other bioactive dietary components may “program” enteric microflora colonization that affect gut health and food safety. For example, Yan et al. (2005) reported that conditioning broilers fed a diet low in calcium and phosphorus for 90 hours post-hatch improves intestinal calcium and phosphorus absorption at 32 days of age, and increases the expression of the gene for the mineral transporter protein throughout the life of the bird. Angel and Ashwell (2008) demonstrated that broilers fed a moderately deficient conditioning diet for the first 90 hour post-hatch were more tolerant to a P-deficient grower and finisher diet, but they were also heavier, had better feed conversion, and they had higher tibia ash and P retention. The work of Angel and Ashwell demonstrate that epigenetic imprinting and nutritional adaptation to low dietary Ca and P is indeed possible and likely for other minerals as well. 

Based on the concepts of epigenetics, imprinting, and adaptive conditioning presented above, several experiments has been done to test various nutritional programming strategies at the Alltech-University of Kentucky Nutrition Research Alliance Coldstream Farm and Alltech’s Center for Animal Nutrigenomics and Applied Animal Nutrition. By evaluating the expression patterns of key functional gene groups, dietary amounts of nutrients that affect homeostatic balance were discovered to depend on the form of the nutrient, levels of and interactions among nutrients, and the timing of administration. Feeding chicks a specifically-formulated diet during the first 72 hours post-hatch has been developed to “condition” the gut for better nutrient utilization and program metabolism that ultimately affects production efficiency, carcass composition, and meat quality. Chicks that have been fed the appropriate conditioning diet, followed by a complementary growing and finishing diet, have improved growth performance and feed efficiency through to market age, and over 70% higher calcium and phosphorus digestion than controls. A programmed nutrition strategy can literally change the nutrient requirement and production efficiency, and may yield a response greater than any single feed additive on the market. Not only can programmed nutrition increase production efficiency that is so important to poultry producers, there is evidence that it improves the meat quality consumers demand, which yields greater potential profits from the poultry products produced. Broilers that have been raised on a programmed nutrition strategy have reduced carcass fat and produce breast meat that has more appealing color, less drip losses during storage, improved oxidative stability, and lower cooking losses.

Although feeding broilers a special nutritional conditioning diet for just 72 hours after hatch presents great opportunities, it is logistically difficult to accomplish in practice using current production systems. Moreover, variation in the time and stress exposure between hatch-pull and placement will affect the effectiveness of the 3-day nutritional conditioning period. However, recent hatch-brood technology (http://www.hatchbrood.nl/hatchbrood/product.php) offers a practical means to deliver specially formulated diets during the first 2 or 3 days post-hatch in the controlled environment of a hatchery. The hatchery of the future will be a place that will do much more than simply hatch and vaccinate chicks: it will also be the place where the chicks will be conditioned better tolerate the challenges of life, and be programmed for optimum nutrient efficiency. Nutritional science is no longer a matter of supplying minimally required nutrients in the ideal balance to achieve desired production and welfare goals. We now know that nutrition is a process that can be programmed to succeed by strategic perinatal diet manipulation by in ovo and post-hatch feeding.

References

Angel, R., and Ashwell, C.M. (2008). Dietary conditioning results in improved phosphorus utilization. Proceedings of the XXIII World’s Poultry Congress, Brisbane, Australia, June 30 – July 4, 2008.

Bohórquez, D. V., Santos, Jr., A. A., and Ferket, P. R. (2008). In ovo feeding and dietary ß-hydroxy-ß-methylbutyrate effects on poultry quality, growth performance and ileum microanatomy of turkey poults from 1 to 11 days of age. Poultry Sci. 87(Supplement 1):139.

Havenstein, G. B., Ferket, P. R., Grimes, J. L., Qureshi, M. A., and Nestor, K. E. (2007). Comparison of the performance of 1966 vs. 2003-type turkeys when fed representative 1966 and 2003 turkey diets: growth rate, livability, and feed conversion. Poult. Sci. 86: 232-240.

Havenstein, G.B., Ferket, P. R., and Qureshi, M. A. (2003). Carcass Composition and Yield of 1957 Versus 2001 Broilers When Fed Representative 1957 and 2001 Broiler Diets. Poult. Sci. 82:1509-1518. 

de Oliveira, J.E., P.R. Ferket, C.M. Ashwell, Z. Uni, and C. Heggen-Peay, 2007. Changes in the late term turkey embryo metabolism due to in ovo feeding. Poultry Sci. 86(Supplement 1):214.

Foye, O. T., Uni, Z., and Ferket, P. R. (2006a). Effect of in ovo feeding egg white protein, beta-hydroxy beta-methylbutyrate, and carbohydrates on glycogen status and neonatal growth of turkeys. Poult. Sci. 2006 85:1185-1192.

Foye, O. T., Uni, Z., McMurtry, J. P., and Ferket, P. R. (2006b). The effects of amniotic nutrient administration, "in ovo feeding" of arginine and/or beta-hydroxy-beta-methyl butyrate (HMB) on insulin-like growth factors, energy metabolism and growth in turkey poults. Int. J. Poult. Sci. 5 (4):309-317.

Foye, O. T., Uni, Z., and Ferket, P. R. (2007). The effects of in ovo feeding arginine, β-hydroxy-β-methyl butyrate, and protein on jejunal digestive and absorptive activity in embryonic and neonatal turkey poults. Poult. Sci. 86:2343–2349

Kaati, G., Bygren, L. O., and Edvinsson, S. (2002). Cardiovascular and diabetes mortality determined by nutrition during parents’ and grandparents’ slow growth period. Eur J. Hum. Genet: 10:682-688.

Pembrey, M.E., bygren, L.O., Kaati, G., Edvinsson, S., Northstone, K., Sjostrom, M., Golding, J., and the ALSPAC Study Team (2006). Sex-specific, male-line transgenerational responses in humans. European Journal of Human Genetics 14:159-166.

Pray, L. A. (2004). Epigenetics: genome, meet your environment. The Scientists 18(13,14).

Smirnov, A., Tako, E., Ferket, P. R., and Uni, Z. (2006). Mucin gene expression and mucin content in the chicken intestinal goblet cells are affected by in ovo feeding of carbohydrates. Poult. Sci. 85:669-673.

Tako, E., Ferket, P. R., and Uni, Z. (2004). Effects of in ovo feeding of carbohydrates and beta-hydroxy beta-methylbutyrate on the development of chicken intestine. Poult. Sci. 83:2023-2028. 

Tako, E., Ferket, P. R., and Uni, Z. (2005). Changes in chicken intestinal zinc exporter mRNA expression and small intestine functionality following intra-amniotic zinc-methionine administration, J. Nutr. Biochem. 15:339-346.

Uni, Z., Ferket, P. R., Tako, E., and Kedar, O. (2005). In ovo feeding improves energy status of late-term chicken embryos. Poult. Sci. 84(5):764-770.

Uni, Z., and Ferket, P. R. (2003). Enhancement of development of oviparous species by in ovo feeding. United States Patent No. 6,592,878.

Uni, Z., and Ferket, P.R. (2004). Methods for early nutrition and their potential. World’s Poultry Science Journal 60:101-111.

Yan, F., Angel, R., Ashwell, C., Mitchell, A., and Christman, M. (2005). Evaluation of the broiler's ability to adapt to an early moderate deficiency of phosphorus and calcium. Poult Sci. 84:1232-41.