Limestone and oyster shell for brown layers in their second egg production cycle

Abstract

This study aimed at evaluating the effect of dietary calcium levels and the replacement of calcium sources with different particle size compositions on the performance and egg quality of brown layers in their second egg production cycle. A randomized block experimental design was applied with 12 treatments in a 3x4 factorial arrangement: three calcium levels (2.6, 3.2, 3.8 %) and four combinations of calcium sources (1- 100% fine limestone (FL), 2- 50% FL + 50% coarse limestone (CL), 3- 50% FL and 50% oyster shell (OS), 4- 50% FL and 25% CL+ 25 %OS), with six replicates of eight birds each. Calcium sources were analyzed for geometric mean diameter (GMD) and in-vitro solubility. The following performance and egg quality parameters were evaluated: egg weight (EW, g), egg production (% Eggs), egg mass (EM %), feed intake (FI g), feed conversion ratio (FCR kg/dz and FCR kg/kg), mortality (% Mort.), specific egg gravity (SG), percentages of yolk (Y%), albumen (Alb%) and eggshell (ES%), eggshell thickness (EST), eggshell breaking strength (BS), eggshell weight per surface area (EWSA), Haugh unit (HU), yolk index (YI) and yolk color. Performance and internal egg quality were not affected by the treatments (p>0.05). Blocks had a significant effect on (p<0.05) FI and FCR (kg/dz and kg/kg). Treatments significantly influenced external egg quality, which improved as dietary calcium levels increases and when up to 50% fine limestone was replaced by combinations of coarse limestone with oyster shell

Exploratory study on characteristics of oyster shell and eggshell quality in Chile

“…These ranged between 33% and 35%, and show small variability for samples between farms. These values were slightly lower than those reported by other authors, averaging percentages of 39.5% (Ahmed et al 2013), 37.4% (Çatli et al 2012), 37.5% (Saunders-Blades et al 2009) and 36.4% (Pizzolante et al 2011). As stated by Saunders-Blades et al (2009), oyster shell would be one calcium source that shows quite stable calcium contents, and the data above clearly supports that statement.…”

“…Among them, the most important sources are limestone and oyster shell (Roland 1986, Guinotte and Nys 1991, Pizzolante et al 2011, Çatlı et al 2012, and some authors consider oyster shell to have a greater bioavailability than limestone (Brister et al 1981, Saunders-Blades et al 2009. Oyster shell is widely preferred for the nutrition of laying hens in Chile, as well as in other countries, and is regarded as an excellent source of calcium (Roland and Bryant 1999, Saunders-Blades et al 2009, Pizzolante et al 2011. Oyster shell is a sedimentary rock with varying degrees of compaction, and it is mostly composed of calcareous shells remains from marine organisms, with different proportions of clastic materials (Çatli et al 2012).…”

Effect of Different Fractions of Dietary Limestone on Concentration of Calcium, Phosphorus, Magnesium, and 25-Oh D3 in Laying Hens Serum

“…Найпоширеніше джерело Кальцію для птиці -вапняк, який містить близько 38 % Кальцію у складі карбонату [12,13]. Дефіцит Кальцію у раціоні призводить до зменшення споживання корму, зниження яєчної продуктивності, ваги яйця, міцності яєчної шкаралупи [4,10].…”