Chicken embryo development: metabolic and morphological basis for in ovo feeding technology

Abstract

Broiler embryonic development depends on the nutrients that are available in the egg, which includes mostly water, lipids, and proteins. Carbohydrates represent less than 1%, and free glucose only 0.3%, of the total nutrients. Considering that energy requirements increase during incubation and metabolism is shifted toward the use of glycogen stores and gluconeogenesis from amino acids, extensive muscle protein degradation in the end of incubation can compromise chick development in the initial days after hatch. Significant prehatch changes occur in embryonic metabolism to parallel the rapid embryonic development. Oral consumption of the amniotic fluid begins around 17 d of incubation and promotes rapid development of the intestinal mucosa, which is characterized by morphological changes and increased expression and activity of enzymes and transporters. Furthermore, ingested substrates are stored as nutritional reserves to be used during hatching and in the first week after hatch. At hatch, this limited-nutrient store is directed to the functional development of the gastrointestinal tract to enable assimilation of exogenous nutrients. In ovo feeding is an alternative to deliver essential nutrients to chick embryos at this critical and challenging phase. The improved nutritional status and physiological changes triggered by in ovo feeding can resonate throughout the entire rearing period with significant health and economic gains. The present review addresses the main changes in metabolism and intestinal development throughout incubation, and also addresses scientific advances, limitations and future perspectives associated with the use of in ovo feeding that has been regarded as an important technology by the poultry industry.

In Ovo Injection of GABA Can Help Body Weight Gain at Hatch, Increase Chick Weight to Egg Weight Ratio, and Improve Broiler Heat Resistance

“…In ovo fed nutrients are stored as reserves and used during hatching until the end of the first week after hatch [ 26 ]. Moreover, it appears that the effects of in ovo feeding were consistently noticed within the first two weeks of the chicks’ life [ 27 ].…”

The Effects of In-Ovo Injected D-Glucose Monohydrate and Ascorbic Acid on Hatchability, Body Weight and Early Post-Hatch Performance of Geese

“…X 2 = Chi-square table value, df = degree of freedom. Means within a row not sharing a common superscript are significantly different at P ≤ 0.05. crucial for survival after hatch as the only source of nutrients until exogenous feeding is provided to the chicks (Givisiez et al, 2020). It contains macromolecular complexes comprising lipids, proteins, vitamins, minerals, and other essential micronutrients (Bauer et al, 2013).…”

In ovo Feeding as a Tool for Improving Performance and Gut Health of Poultry: A Review

“…Albumen, yolk, and eggshell are the repertoire of the energy and nutrition for the developing chicken embryo. During embryogenesis, different extraembryonic membranes–yolk sac, amnion, chorion, and allantois—play a role in nourishment, protection, respiration, and the storage of metabolites ( 10 ). Beneath the eggshell, through a series of developmental processes, a fertile egg transforms into a chick.…”

“…This development enhances embryonic growth to reach a structurally complete chicken body around 14 days of incubation ( 11 ). The embryo starts thriving on the nutrients conserved within the egg—a rich source of proteins and lipids but a very low amount of carbohydrates (~1% of total nutrients) ( 10 ). When deficiency occurs at the second week of incubation, intervention through IOF or IOS helps deflect the effect of nutritional deficiency.…”

“…When deficiency occurs at the second week of incubation, intervention through IOF or IOS helps deflect the effect of nutritional deficiency. During the last week of embryonic development, the embryo gets energy through gluconeogenesis in the liver and yolk sac ( 10 ). When yolk sac glycogen depletes, the yolk sac starts maintaining glucose homeostasis and acts as a source of nutrients.…”