Factors which can influence this process would generally be associated with:
• Nutritional deficiencies in the integrity of the hen’s skeleton that may lead to problems in the eggshell quality. • Low mineral intake, especially of calcium, due to insufficient supply or availability. • Intestinal dysbiosis affecting intestinal integrity and absorption. • Heat stress is another important factor that causes the loss of the reserves of bone calcium. When animals hyperventilate, respiratory acidosis occurs. This is compensated by the mobilisation of carbonates from the bone. These carbonates are bound to calcium, so there is a loss of this mineral, and, indirectly, the quality of the eggshell is affected.
Bone content and mineral density, as well as the proportion
of the different types of bone (cortical, trabecular, or medullary), can change dramatically during the laying period. Over time, hypocalcemic periods when the medullary bone is mobilised cause a gradual diffusion of the medullary bone through the spaces of the structural bone, when it is redeposited. This diffuse deposition does not provide the same level of protection over structural bone to prevent its resorption and, therefore, mobilisation of both trabecular and cortical bone occurs. At the end of the production cycle, the cortical bone layer is very
37.5
36.5 37
35.5 36
thin, few trabecular structures remain, and the medullary bone is widespread in the medullary cavity. This can lead to problems such as fractures, crooked keels and osteoporosis that may appear towards the end of the laying period which is related to the stability of the structural bone, rather than with the reserve of medullary bone. Other dietary minerals and trace elements also play a major role
regarding eggshell quality. Most studies demonstrate the impact of phosphorus, vitamin D3, manganese, copper, zinc, chromium, etc. on eggshell quality. Feed additives can also contribute to the same purpose. To examine better use of dietary calcium and increase Serum calcium levels, consideration is given to the use of highly
0.342 0.344 0.346 0.348 0.35
34.5 35
34
bioavailable calcium sources by way of feed additives. Protical4+ ®
0.338 0.34
34 designed by Techna is designed to improve intestinal absorption
by providing sources of calcium which will increase the proportion of dietary calcium directly in the blood. The mode of action is to increase the calcium and phosphorus storage capacity and reduce hen dependency on calcium from the medullary bone, therefore, strengthening the bone framework and avoiding related problems in the eggshell quality. By maximising intestinal absorption of calcium for egg production it can maintain the internal balance of the bird’s calcium levels and optimise the laying process to extend the laying peak, slow down the post-peak decrease in production, and prevent egg breakage and fractures.
35.5 36
34.5 35
37.5
36.5 37
Trial data A study using a more bioavailable form of calcium (Protical4+ ®
)
demonstrated the positive effect such a product has on eggshell quality. Experiments were conducted on two groups that each comprised of 240 white commercial layers. Two different treatments were applied: Group A was the control group and was fed with a layer feed containing 3.6% of Ca of which 80% was in coarse carbonate form. Group B was fed the same nutritional level as group A except that 0.2% of Protical4+ ®
was added.
The supplementation phase began as animals reached 61 to 70 weeks old for the 2 groups. In this study, group B (Protical4+ ®
at 0.2%) ended up having all
round better shell quality than group A (Control feed). Higher shell quantity and an increase in shell thickness were observed in group B as opposed to group A. Shell index was also higher for group B than group A. In addition, eggshell solidity (Static Stiffness and Fracture Force) was improved by using PROTICAL4+®
supplementation in feed.
Additionally, group B achieved higher values regarding bone strength criteria (rigidity, maximum force and fracture force).
36.9 Effect of Protical 4+ ® 37.5
36.5 37
35.5 36
34.5 35
34
0.342 0.344 0.346 0.348 0.35
0.338 0.34
Shell Thickness estimate at 70 weeks Control
Fracture force (N) at 65 weeks Control
Shell Thickness estimate at 70 weeks Control
Protical 4+ ® Protical 4+ ® Protical 4+ ®
a,b means followed by different letters are significantly different (p<0.05)
In conclusion, the use of supplements in layer feed like PROTICAL4+®
has proved beneficial on eggshell quality without negatively interfering with bone mineralization and solidity. Using more bioavailable calcium sources, therefore, can also be efficient for increasing eggshell quality, preserving the hen’s skeleton health, and may even allow extended laying periods due to improving the economic optimum through reducing downgraded eggs.
FEED COMPOUNDER JANUARY/FEBRUARY 2023 PAGE 27
Fracture force (N) at 65 weeks Control
Fracture force (N) at 65 weeks Control
Protical 4+ ® Protical 4+ ® 0.349 b 35 35 a 0.349 36.9 36.9b on egg and bone quality
0.342 35 0.342 a
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