Evaluating the efficacy of in vitro and in vivo methods for assessing nutrient digestibility in Sapsarees each age

This study evaluated the comparison between <italic>in</italic> <italic>vitro</italic> and <italic>in vivo</italic> methods for predicting nutrient digestibility across different life stages in Sapsarees. The research performed both <italic>in vitro</italic> methods of dog gastrointestinal conditions such as stomach and small intestine conditions and <italic>in vivo</italic> methods using 18 Sapsaree groups. Sapsarees were categorized into three groups by age and weight: six puppies (under 1 year; 9.94 ± 5.27 kg), six adult dogs (2-7 years; 23.49 ± 3.90 kg), and six senior dogs (over 8 years; 21.57 ± 2.27 kg). The nutrients examined included dry matter, organic matter, crude protein, gross energy, crude fiber, and ether extract. The significant differences were found in the digestibility of OM, CF, and EE between the methods (<italic>p</italic> &lt; 0.05) except the digestibility of DM in puppies and adult dogs and GE digestibility. In puppies, there were strong linear relationships for OM, GE, CF, and EE with r² values of 0.85, 0.90, 0.85, and 0.82, respectively, between <italic>in vitro</italic> and <italic>in vivo</italic> digestibility. Also, in adult dogs, there were strong linear relationships for DM, GE, and CF with r² values of 0.85, 0.90, and 0.91, respectively, between <italic>in vitro</italic> and <italic>in vivo</italic> digestibility. In the relationship between <italic>in vitro</italic> and <italic>in vivo</italic> digestibility of senior dogs, there were strong linear relationships for OM with r² values of 0.87. The <italic>in vitro</italic> method shows a strong correlation with <italic>in vivo</italic> digestibility and is predicted to have significant potential for practical application.