Guts of Growth: In ovo nutrition

Over the years, improving genetics have allowed poultry to become more efficient at growth and development in the egg and on the farm. Additionally, producers are becoming more efficient at managing production of the breeders and the offspring.

As a result, the brooding phase is increasingly important to set the bird up for success. The incubation period is 21 days for chicks, 28 days for turkeys and can be 28 to 35 days for ducks, depending on the breed. Due to the efficiencies of poultry, it has become critical to focus on early nutrition of the bird when their systems are developing so they can mature faster.

Focusing on early nutrition is not a new concept, as nutritionists have been using pre-starter and starter feeds for a long time in different types poultry production. Additionally, producers have used and improved on ways to give young birds as early access to feed and water as possible.

Recently, in broilers, different companies around the world and in Canada have started to feed chicks in the hatchery just as they are pipping out of their shells. This type of feeding requires specialized equipment at the hatchery that allows for feeder space on the hatchery box and allows the box to fit in the hatcher.

The theory behind this type of feeding is the chicks will have access to feed as soon as they hatch without waiting for the starter feed when they reach the farm. Ideally, this type of early feeding would allow the chick to transition from using their yolk, which is high in fat, to using feed, which is high in carbohydrates, to allow for earlier intestinal maturation.

Around 28 years ago, in ovo technology – piercing the developing egg to inject a solution – first became available for vaccine delivery in the broiler hatchery. This technology proved to be advantageous for the hatchery and the farmer. The hatchery had a safe, efficient and effective way to vaccinate chick without too much handling and the flock on the farm experienced good protection without the need to handle or stress the birds.

Normally, in ovo vaccination occurs between 17 and 19 days of incubation when the egg is transferred from the setter to the hatcher. This technology has been proven to be safe and efficacious.

In ovo injection in the hatchery is not a new technology, but the concept of using this method for early feeding of the embryo is. Researchers have studied in ovo feeding in an academic setting for several years. Normally, the developing egg and resulting young bird get their nutrients, immune protection and a significant portion of their microbiota from their mother hen. However, with the rapid growth of the embryo and if there is a stress to the mother or the egg these essential components may be impacted and be limited.

In ovo feeding was developed as a strategy to introduce different components, such as nutrients, probiotics, prebiotics and plant extracts, to overcome these limitations as well as to jump-start the growth of the embryo. The developing embryo in the fertilized egg begins to “eat” the amnion, the egg white, around the 13th and 15th day in the developing egg and this continues until the day the bird pips from the egg.

Usually, injection with in ovo feed has been tested around the 17th to 19th day of embryo growth to pair with when the egg is given in ovo vaccination and when the egg moves from the setter to the hatcher. The amnion material often gets ingested into the lungs and intestine. As a result, in ovo feeding has most often been used to enhance intestinal health and injection into the amnion has been one of the most tested methods.

Depending on the components used in in ovo feeding solution, some researchers have suggested that in ovo feeding between the 17th and 18th day in the developing egg creates an intestinal tract that is functionally equivalent to a two-day-old bird compared to regularly fed birds based on the intestinal development as well as the increased ability to digest and absorb nutrients.

Some studies have found these benefits begin several days after injection, are maintained to day of hatch and several days after hatch. Some studies with broilers have noted changes maintained to market age, especially if related to skeletal development.

Often a limitation of the studies is how long after placement the birds are watched to see changes and whether the feed contains products in them to continue to encourage this growth. Nevertheless, in ovo feeding should be followed up with early feed and water to the young bird to encourage the transition to complete feed and help maintain this development throughout the flock.

Many different components have been tested either alone or in combination for in ovo feeding, including probiotics, prebiotics, egg white proteins, amino acids, carbohydrates, mannanoligosaccharide based polymers, nucleotides, electrolytes, minerals, vitamins, plant extracts and creatine. Often, these products are familiar as they have also been used in other early feeding programs either at the hatchery or at the farm.

Probiotics and prebiotics have been used to start the development of a mature intestinal microflora. The selection of the probiotic, beneficial bacteria, to use is important. The strain of the bacteria and what it releases can play an important role in how that bacteria colonizes the developing gut, functions and what it can do.

Egg white protein and amino acids (e.g., L-arginine, L-lysine, threonine) have been found to support embryo development and post-hatch performance. Nucleotides, vitamins C and E, plant extracts (e.g., from thyme), zinc and selenium have been found to enhance immunity. The type of plant and extract used has an impact on the function and must be tailored to what is needed in the feeding program.

Carbohydrates and creatine have been shown to support muscle growth either indirectly or directly.

Trace minerals (e.g., selenium, zinc, manganese, copper) and vitamin D have been shown to support bone strength. Several studies that have used minerals in in ovo feeding programs have used minerals in forms that are highly bioavailable to support consumption by the embryo. In all these cases, the dose of the product was critical, as too little may have no effect and too much may cause a decrease in hatchability.

Various factors influence how well in ovo application works and supports good hatchability. These factors include: The volume of solution given; the concentration of the product; preparation of the solution; sanitation; site of injection; injection depth; and equipment. Additionally, different species have different critical times for embryo development and when injection can happen.

What may work best for in ovo vaccination may not work best for in ovo feeding and both may not work well when given together. One of the keys for developing an in ovo feeding program that will work commercially is being able to apply it during the time of in ovo vaccination, so the egg is not handled or pierced more than once. Consequently, an in ovo feeding program has been well tested in an academic setting and is beginning to be tested commercially but has not yet been commercialized for access.

Various early feeding programs are becoming integral to poultry production and in ovo feeding is an innovative strategy that is on the horizon.

Kayla Price is poultry technical manager for Alltech Canada and is an expert in poultry intestinal health.