Pulse-based Vegan Dog Food: Examination of Digestibility with or without Added Enzymes in Adult Dogs and Ileal Cannulated Pigs as a Model

• Author / Creator

  Van Straten, Whitney

• Demand for vegan dog foods is growing, yet little research has been conducted
  concerning the digestibility of these foods for dogs. The pulses and pulse protein concentrates
  that provide protein in these foods contain anti-nutritional factors (ANF), which may reduce
  nutrient digestibility. Addition of exogenous enzymes may help increase the digestibility of these
  foods, however, due to constraints on companion animal research, studies using dogs alone may
  not be able to accurately determine enzyme effectiveness.
  For the present study two diets were formulated: a low protein diet (L) including mainly
  field pea and lentil flours, and a high protein diet (H) including mainly field pea and lentil
  protein concentrates. In chapter 2, ileal cannulated pigs were fed these diets either raw (R),
  extruded (E), extruded with enzyme added before extrusion (E+P), or enzymes added after
  extrusion (E+A). The enzyme blend included protease, phytase, cellulase and xylanase. Feces
  and digesta were collected to determine apparent total tract digestibility (ATTD) and
  standardized ileal digestibility (SID) of the diets. Extrusion alone increased ATTD of gross
  energy (GE) by 1% and SID total AA by 4% compared to R (P < 0.05). The addition of the
  enzyme blend after extrusion increased ATTD of crude protein (CP) and GE by 1%, ATTD of
  ash by 11-19% (P < 0.05), and increased SID of total AA by 2% (P < 0.05) compared to E.
  However, the addition of the enzyme blend before extrusion resulted in lower ATTD of organic
  matter (OM), CP, and GE, and lower SID of AA compared to E (P < 0.05), likely due to
  overheating during processing.
  In chapter 3, dogs were fed the same formulations as controls which were extruded
  without enzymes (C), extruded with enzyme added before extrusion (P), or enzyme added after
  extrusion (A). Fecal samples were collected to measure ATTD, fecal metabolites and fecal
  consistency. Unlike for pigs, ATTD of OM, CP, crude fat (EE), GE, or ash did not increase for
  dogs when enzymes were added after extrusion. However, the addition of enzymes after
  extrusion did increase concentrations of glucose, xylose, propionic and acetic acids in dog feces
  compared to C (P < 0.05), indicating the enzymes did hydrolyze some of the insoluble fiber in
  the diets leading to increased bacterial fermentation. The addition of the enzymes after extrusion
  also resulted in feces with higher moisture content than for C (P < 0.05), causing loose stools for
  the dogs. Addition of enzymes prior to extrusion resulted in ATTD of CP lower than C (P <
  0.05). Although the ATTD values from pigs were greater than from the dogs, their results
  followed similar trends and comparison by regression analysis resulted in high R2
  values for GE,
  OM and CP (R
  2 > 0.7).
  In conclusion, extrusion and the addition of enzymes after extrusion increased the
  digestibility of pulse flour and protein concentrate based diets for growing pigs. The addition of
  enzymes after extrusion did not increase the digestibility of pulse flour and protein concentrate
  based diets for adult dogs, but did increase the concentrations of fecal metabolites indicating that
  the enzymes hydrolyzed some insoluble fiber. However, enzyme addition after extrusion also
  resulted in loose stools. Addition of enzymes before extrusion resulted in lower digestibility of
  the diets for both pigs and dogs. Overall, the addition of enzyme after extrusion can be used to
  increase the digestibility of pulse-based diets for growing pigs, and has some effect on dog
  intestinal microbiome and fecal quality. Comparison of digestibility values from the pigs and
  dogs resulted in high R2 values, indicating that pigs can be used as a model for dog food
  digestibility studies.

• Subjects / Keywords

  • Dog
  • Enzymes
  • Pig
  • Pulses
  • Digestibility
  • Extrusion
  • Pea
  • Lentil
  • Protein concentrate

• Graduation date

  Fall 2023

• Type of Item

  Thesis

• Degree

  Master of Science

• DOI

  https://doi.org/10.7939/r3-6kvb-af15

• License

  This thesis is made available by the University of Alberta Libraries with permission of the copyright owner solely for non-commercial purposes. This thesis, or any portion thereof, may not otherwise be copied or reproduced without the written consent of the copyright owner, except to the extent permitted by Canadian copyright law.