Phytase super-dosing on bone parameters and positivity of the calcium epithelial carrier Calbindin-D28k in quails (Coturnix coturnix japonica) under different temperatures.

Apolônio Ribeiro; Raiane Silva; Fabiano Sellos Costa; EDIJANIO DA SILVA; José Evangelista Santos Ribeiro; Edilson Saraiva; Fernando Costa; Ricardo Romão Guerra

Just Accepted

This article has been peer reviewed and accepted for publication. It is in production and has not been edited, so may differ from the final published form.

Phytase super-dosing on bone parameters and positivity of the calcium epithelial carrier Calbindin-D28k in quails (Coturnix coturnix japonica) under different temperatures.

Apolônio Ribeiro , Raiane Silva , Fabiano Sellos Costa , EDIJANIO DA SILVA , José Evangelista Santos Ribeiro , Edilson Saraiva , Fernando Costa , Ricardo Romão Guerra

Abstract

Context. Thermal stress causes significant changes in the bioavailability of minerals, notably calcium, in laying birds, resulting in reduced egg production, and compromising egg quality. Therefore, it is necessary to use additives that provide better nutrient availability and minimize the negative effects caused by high temperatures. Aim. The study aimed to evaluate the effects of a super-dose of phytase on bone parameters and on the positivity of the epithelial calcium transporter calbindin-D28K in laying quails submitted to different temperatures. Methods. Seven hundred and twenty (720) Japanese quails in the production phase were used, distributed in a completely randomized design, in a 5x3 factorial scheme, five levels of phytase (0; 500; 1000; 1500; and 3000 FTU/Kg), and three temperature ranges (24; 30 and 36°C), totaling 15 treatments, and six replications of eight birds each. The study began at the eighth week of age and continued for two cycles of 21 days, totaling 42 days of experiment. Bone parameters of the tibias and calbindin-D28K positivity were measured by immunohistochemistry. The data were submitted to variance, Tukey, and regression analyses. Key results. At temperatures of 24°C, birds had higher averages for proximal, medial, and distal diaphyses when compared to 30 and 36°C, and greater breaking strength of the tibias than those at 36°C. There was an increasing linear effect for the medial diaphysis and Seedor index in the tibias with increasing phytase levels. Calcium (Ca) in the tibias was higher in birds kept at 30°C at a level of up to 1000FTU of phytase, when compared to those at 24 and 36°C, equaling 1500FTU, and lower at 3000FTU. There was a quadratic effect for phosphorus (P) and the Ca:P ratio in the tibias of quails submitted to increasing levels of phytase. Quails kept at 30°C showed greater positivity for anti-calbindin-D28K in the duodenum and jejunum. Phytase doses of 500 and 1000FTU increased Calbindin-D28K positivity in the duodenum of quails kept at 30°C. At a level of 1500FTU, phytase provided greater eggshell thickness and greater positivity for Calbindin-D28K in the uterus of quails kept at 36°C. Conclusion. Therefore, it is recommended to use 1500 FTU for Japanese quail exposed to high temperatures.

AN24057 Accepted 31 May 2024