SHELL QUALITY

10 July 2020

SHELL FORMATION AND QUALITY

MANAGING CALCIUM REQUIREMENTS IN LAYING HENS BY CHOOSING THE IDEAL SOURCE

Shell quality

SHELL CHARACTERISTICS

97–98% of the eggshell is composed of calcium carbonate.
Shell thickness depends on the amount of calcium deposited during shell formation inside the uterus and on the length of time the egg remains there (up to 15 hours).
From the moment the egg enters the uterus and shell deposition begins, there is an increase in the synthesis of active vitamin D and intestinal calcium-transport proteins, resulting in a doubling of calcium absorption.
The calcium required for shell deposition mainly comes from intestinal absorption and bone remodeling.
In hens fed a balanced diet with good calcium sources, dietary calcium represents the primary source. In cases of inadequate or incorrect calcium intake, a specific bone matrix is mobilized. This matrix forms in laying hens under hormonal influence a couple of weeks before the onset of egg laying and is continuously remodeled.
This matrix can supply up to 40% of calcium requirements when the hen is not feeding (and therefore not ingesting dietary calcium), such as during dark periods, stress conditions, or when the diet is unbalanced.

HOW TO IMPROVE SHELL QUALITY

Since most shell synthesis occurs during dark hours, the contribution of bone calcium to shell formation is essential.
However, the greater the calcium contribution from bone remodeling, the thinner the shell becomes.
This is why an inadequate calcium intake can be compensated for, but results in reduced shell strength.
Factors influencing proper calcium intake include: calcium source, particle size, phosphorus levels, and vitamin D levels.
Vitamin D, by regulating calcium absorption, is just as important as calcium itself.
High phosphorus levels inhibit intestinal calcium absorption and its mobilization from bone matrix. To ensure proper calcium absorption, the calcium-to-phosphorus ratio should be maintained at 4:1 during lay.
An acidic intestinal pH maximizes calcium and phosphorus absorption; for this reason, dietary acidification with organic acids plays an important role in laying hens.

CALCIUM SOURCES

  • CALCIUM CARBONATE
    This is the least expensive calcium source and can be either mined or synthetic.
    When choosing this source, particle size is crucial. Finely ground limestone is rapidly absorbed and is therefore useful for quickly replenishing bone matrix or during shell formation when the hen is feeding. However, since shell formation mainly occurs during dark hours, it is advisable to provide coarser particles that remain longer in the gastrointestinal tract.
    A ratio of 60:40 between coarse and fine particles is recommended.
    Limestone solubility also plays a key role in calcium assimilation and depends on intestinal pH: the more acidic the intestinal pH, the greater the solubility.
  • OYSTER SHELLS / SHELL GRIT
    A calcium carbonate source derived from crushed bivalve mollusk shells. The particle size and composition of this source delay solubility by 5–10 times compared to synthetic calcium carbonate.
  • CALCAREOUS MARINE ALGAE
    Marine algae contain pigments, vitamins, prebiotics in the form of complex carbohydrates, and chelated trace minerals.
    Therefore, calcareous marine algae are not just a calcium source.
    In addition to providing readily absorbable organic calcium, they contain substances involved in maintaining intestinal health, immune status, and egg quality.
    Studies on the use of certain algae species (Sargassum spp.) as dietary supplements have shown improvements in both internal and external egg quality (lower cholesterol levels, more intensely colored yolks, stronger and more pigmented shells).
  • CALCIUM GLUCONATE
    An organic calcium source indicated in cases of deficiency, environmental stress, or management stress, due to its high bioavailability.
    During digestion, calcium gluconate releases gluconic acid, which supports calcium metabolism and energy metabolism during stress conditions (heat stress, excessive bone mobilization, or egg drop syndrome), all of which are responsible for reduced production or product quality.
  • CALCIUM PIDOLATE
    An organic calcium source in which calcium is bound to two molecules of pidolic acid.
    This source has a dual function: supplying calcium while also providing amino acids for protein synthesis. Pidolic acid is a substrate for the production of arginine and proline, essential amino acids for calcium-transport proteins and collagen, a key component of bone and the inner shell membrane.
    This source is recommended during stress periods or as hens age, when calcium absorption and mobilization capacity declines.
    It has been reported that after 40 weeks of age, the ability to metabolize calcium decreases by up to 50%.

Tecnozoo has developed several solutions to address shell quality issues at every stage of the production cycle and during stress conditions.
Tecnozoo offers liquid or powdered complementary feeds containing carefully studied and selected calcium sources, tailored to meet every specific need.
Discover all products for shell quality: https://tecnozoo.it/categoria-prodotto/avicoli/qualita-guscio/

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BIBLIOGRAPHY

  • https://www.unaitalia.com/il-giusto-livello-di-calcio-per-le-ovaiole
  • https://web.terzi.it/zootecnia-2/
  • R. Joshi D. N. Desai A. S. Ranade P. E. Avari – “Effect of Calcium Pidolate on Egg
  • Production and Egg Quality during Last Phase of Production Cycle with Reducing Levels of Inorganic Calcium”
  • W. WASHBURN – “Incidence, Cause, and Prevention of Egg Shell Breakage in Commercial Production”
  • https://www.ncbi.nlm.nih.gov/books/NBK232332/ – Effect of Environment on Nutrient Requirements of Domestic Animals.
  • https://thepoultrysite.com/articles/factors-influencing-shell-quality
  • Elaroussi et al. – “Calcium homeostasis in the laying hen. Age and dietary calcium effects”
  • Olubunmi Gabriel Fasanmi – “Therapeutic Importance of Calcium Gluconate r in Cage Layer Fatigue (CLF), the Effects on Egg Production, Haematology and Serum Biochemistry of Commercial Layers”
  • Al-Zahrani et al. – “The effect of supplementation of two levels of calcium pidolate and two levels of 25- hydroxycholechaciferol on egg quality in commercial laying hens”
  • Gilles Tran et al – “Seaweeds for livestock diets: A review”
  • Rosie Burgin – “Benefits of seaweed in poultry diets”
  • Heuzé V., Tran G., Giger-Reverdin S., Lessire M., Lebas F., 2017 – Seaweeds (marine macroalgae)