Effect of Rock Phosphate on Nutrient Digestibility and Histopathology of Weanling Rabbit (Oryctolagus cuniculus)

Odu O, Agedeson JT and Kuka TT

Published on: 2025-11-24

Abstract

Calcium and phosphorus are essential for controlling metabolic processes and skeletal growth in animal. As an alternative to bone meal, rock phosphate (RP), a naturally occurring calcium-phosphorus-rich material, shows potential. However, the assessment of heat-treated rock phosphate (HTRP) as a bone meal substitute in rabbit diets has been influenced by the instability of fluoride at high temperatures. Fifty four, seven-weeks-old cross-bred mongrel weanling rabbits were utilised. The rabbits with average initial weights of 599.65±2.70 g were randomly allotted to nine dietary treatments in completely randomised design. Feed and water were available ad-libitum. RP replaced bone meal at inclusion levels of 0, 25, 50, 75, and 100% respectively. At the end of the study (70 days), faecal materials were sampled per treatment and pooled together for evaluation of nutrient digestibility. Three rabbits per treatment were euthanised. Lungs, liver and kidney were harvested for histopathology evaluation following standard procedures. Data were subjected to orthogonal contrast using SAS 9.4 (2023). Dry matter and ether extract did not differ significantly (P>0.05) between treatments. With the exception of HTRP against raw rock phosphate (RRP) diet, there was no discernible difference (P>0.05) in the orthogonal comparison in the crude protein of rabbits. Crude fibre digestibility revealed that rabbits fed control diet differed significantly (P<0.05) with (HTRP or RRP at inclusion levels). Replacement of BM with HTRP and RRP up to 100% and 75%, respectively, had no effect on histopathology of the rabbits. It is therefore concluded that HTRP can be utilised at all levels of inclusions, while RRP 75% without deleterious effect on the digestibility and histopathology.