專討摘要

Poultry by-product meal is a common source of animal protein used in the pet food. Hydrolysed poultry by-product meal (HPM) is a novel ingredient obtained through the enzymatic cleavage process of poultry by-product raw materials, including the viscera and deboned body parts not suitable for human consumption. Hydrolysed poultry by-product meal is a potential alternative protein source for cat foods. Therefore, this study aimed to investigate the effects of different dietary inclusion levels of HPM on nutrient digestibility, faecal characteristics, intestinal fermentation products, urinary characteristics, and nitrogen balance in cats. In the experiment, thirty healthy adult cats were assigned to five dietary treatments containing 0%, 5%, 10%, 20%, or 30% HPM in extruded diets. The results showed that HPM inclusion did not significantly affect the apparent total tract digestibility of most nutrients. Although starch gelatinisation was lower in the diet containing 30% HPM, starch digestibility remained high and did not differ significantly among treatments. Faecal characteristics like production, pH and fecal score were generally similar among dietary treatments. Regarding intestinal fermentation, total short-chain fatty acid concentrations did not differ significantly among treatments (p > 0.05) . However, lactate concentrations increased linearly with increasing HPM inclusion, while branched-chain fatty acid concentrations showed a significant quadratic response (p < 0.05). Taken together, these results indicate HPM inclusion diets may get higher fermentation activity in the colon of cats. Urinary characteristics, including urine volume, specific gravity, and pH, were not significantly affected by dietary treatment (p > 0.05). Cats fed diets containing 5% and 10% HPM tended to have higher nitrogen retention, although this difference was not statistically significant (p = 0.083). This tendency may be associated with the amino acid composition of HPM, but further research is needed to confirm this possibility. In conclusion, HPM can be included at levels up to 30% in extruded cat diets without significantly affecting nutrient digestibility or faecal and urine characteristics.  Nevertheless, the changes in lactate and branched-chain fatty acids indicate that HPM may affect intestinal fermentation. Further studies are needed to investigate its effects on these products of peptide fermentation in the colon in cats.