The production of eggs with high shell quality in commercial laying hens is very important for profit maximisation. Eggshell quality decreases as chickens age, and the production of broken, cracked, thin-shelled eggs increase, especially at high ambient temperatures. At the same time, under these conditions, the hormonal balance is disturbed and the natural immunity is weakened. This study investigated the effects of adding Vitalic Shell Support to the rations of older commercial laying hens under heat stress on egg production characteristics and eggshell quality.
R&D Manager, Feed Additive Department
Intermak A.S.
INTRODUCTION
Turkey is located in a temperate latitude on the globe. The fact that in some regions the temperature rises above 40 °C disturbs the mechanism for regulating body temperature in poultry, whose ideal ambient temperature should be 20-27 °C. If the temperature rises above 30 °C, it is assumed that heat stress has begun. In this case, feed consumption, live weight gain, egg production and shell quality were reported to decrease due to the difficulty in releasing the heat generated in the body to the environment (1).
Calcium carbonate makes up about 95% of the eggshell (2). Calcium has long been a topic of research because of its importance to eggshells. Since chickens do not have sweat glands, they breathe in more water vapor and carbon dioxide during hot summer months. In this process, a high loss of carbon dioxide, an increase in blood pH, and a decrease in calcium ions lead to increased production of thin-shelled or soft-shelled eggs, which may result in a ratio of broken-cracked eggs. Assuming that the average egg yield of chickens is 80%, about 8-10% of the eggs produced are dirty, cracked and broken, resulting in large economic losses (3). It is possible to explain this situation with the mechanism of calcium homeostasis. On the other hand, the element calcium is still a paradox in biological systems. Because calcium metabolism is extremely complicated at metabolic and physiological levels, and it shows its action under the control of many macro-micro elements and different hormonal systems. One of the most interesting aspects of calcium metabolism is that adequate calcium requirements cannot be met simply by adding calcium to the diet. It is observed that calcium metabolism changes under different physiological, health and stress conditions, and even at the organelle level different calcium metabolism occurs.
This study sought to demonstrate the effects of Vitalic Shell Support on yield characteristics and egg quality criteria by adding an equimolar concentration with a high degree of ionization to the ration of aged commercial laying hens under heat stress.
MATERIAL AND METHOD
A total of 100 commercial laying hens of the Lohman line – aged 64 weeks – were used for the experiment. During the fifty-six-day experimental period, various doses of carbonate were administered at equimolar concentrations to isocaloric and isonitrogenous (16% crude protein (CP) and 2,850 kcal metabolic energy (ME)/kg) commercial laying hen rations containing 4.0% calcium (Ca) – 0.40% usable phosphorus (UP) supplements. The experiment was conducted in apartment-type cages, and the experimental facility was automated at a temperature of 30 °C and a relative humidity of 60%. Ventilation was done automatically. Feed and water were given freely. In the experiment, a daily lighting program of 16 hours of light + 8 hours of darkness was applied. The lighting intensity was set at 15 lux. The egg production of the chickens, the number of eggs broken and cracked, feed consumption and feed evaluation coefficients were determined weekly. The experiment was set up according to the experimental design for randomized plots.
This experiment was conducted at Konya Selcuk University, Faculty of Agriculture, Department of Animal Science, Research Centre for Experimental Animals.
RESULTS
ALKALINE THERAPY APPLICATION
Improvement of the characteristics of egg yield
According to the results of the 56-day trial conducted on 64-week-old commercial laying hens under heat stress, the differences between group averages were found to be statistically significant in terms of the effect of Shell Support supplementation with equimolar concentration on egg production. In terms of egg production, the highest value was recorded in the group with ShellSupport supplementation with 77.68% and the lowest value in the control group with 64.40%.
On the other hand, it was found that feed consumption in the experimental groups containing ShellSupport was lower than in the control groups and the groups without Shell Support, and the feed utilisation coefficient was lower.
Decrease in Broken-cracked Egg Ratio
As for the rate of broken cracked eggs, the highest value of 4.82% was observed in the control group. The group with Shell Support achieved 4.12% better results than the control group.
ABSTRACT
The current practice for meeting the calcium requirements of poultry is to add calcium carbonate directly to the ration. In particular, attempting to meet the high calcium requirements of poultry in the laying period in this manner requires the use of calcium carbonate in a high proportion (7%-9%) in poultry rations.
This study investigated the effects of applying Vitalic Shell Support on egg production characteristics and egg shell quality without adding additional calcium to rations for aged commercial laying hens under warm environmental conditions. The addition of Shell Support to the rations of commercial laying hens later in the laying period significantly increased egg production by reducing feed consumption and feed efficiency coefficient without compromising animal health. On the other hand, the addition of Shell Support reduced the rate of broken-cracked eggs.
References
1. Ahmad, H. A., Yadalam, S. S. and Roland, D. A., 2003, Calcium requirements of bovanes hens, International Journal of Poultry Science 2(6), 417-420.
2. Öğün, S., 1981., Tavuklarda değişik kalsiyum fosfor oranlarının yumurta verimine ilişkin ölçütler üzerindeki etkileri, Çukurova Üniv. Zir. Fak. Yayınları: 156, Bilimsel Araştırma ve Inceleme Tezleri: 47, Adana.
3. Tabib, I. ve Onbaşılar, E., 2019, The Structure of Eggshell and Factors Affecting Shell Quality in the Chicken Egg, Journal of Poultry Research,16 (2), 48-54.
About Asli Selvi
Asli Selvi grew up in Turkey. She completed her undergraduate studies in chemistry. In 2014, she started her PhD training in the Department of Animal Breeding. She has been working in the livestock industry for about ten years. Since 2018, she has been working at Intermak A.S. a research and development specialist in the feed additives department.
