Standardized amino acid digestibility and nitrogen-corrected true metabolizable energy of frozen raw, freeze-dried raw, fresh, and extruded dog foods using precision-fed cecectomized and conventional rooster assays

Apparent total tract nutrient digestibility of frozen raw, freeze-dried raw, fresh, and extruded dog foods and their effects on serum metabolites and fecal characteristics, metabolites, and microbiota of healthy adult dogs

Various pet food diet formats are available, but many are poorly studied. The objective of this study was to determine the apparent total tract macronutrient digestibility (ATTD) of frozen raw, freeze-dried raw, fresh, and extruded dog foods and assess their effects on serum metabolites, hematology, and fecal characteristics, metabolites, and microbiota of healthy adult dogs. Ten beagle dogs (4.10 ± 0.74 yr) were used in a replicated 5 × 5 Latin square study to test the following diets: Chicken and Barley Recipe (extruded; Hill's Science Diet [EXT]), Chicken and White Rice Recipe (fresh; Just Food for Dogs [FRSH]), Chicken Formula (frozen raw; Primal [FRZN]), Chicken and Sorghum Hybrid Freeze-dried Formula (freeze-dried raw; Primal [HFD]), and Chicken Dinner Patties (freeze-dried raw; Stella & Chewy's [FD]). The experiment was composed of five 35-d periods, with each ending with fecal and blood collections. Data were analyzed using Mixed Models in SAS 9.4, with P < 0.05 being significant. Treatment was a fixed effect and dog a random effect. Protein ATTD was higher for FRZN and FD than other diets and higher for HFD than FRSH and EXT. Fat ATTD was higher for HFD than FRZN and EXT and lower for EXT than other diets. Fecal output was higher for dogs fed EXT than those fed other diets and higher for dogs fed FRSH than those fed FRZN, HFD, or FD. Fecal pH was lower in dogs fed EXT and FRSH than those fed other diets. Fecal scores were higher (looser) in dogs fed EXT and FRSH than those fed FRZN and FD. Fecal dry matter was higher in dogs fed FD than those fed other diets and higher in those fed FRZN and HFD than those fed EXT and FRSH. In general, fecal short-chain fatty acids were highest in dogs fed EXT, intermediate in dogs fed FRSH and HFD, and lowest in dogs fed FRZN and FD. Fecal isobutyrate and isovalerate were highest in dogs fed HFD, lowest in dogs fed FRSH, and intermediate in dogs fed other diets. Fecal primary bile acids were higher, while secondary bile acids were lower in dogs fed FRSH than in dogs fed other diets. Fecal microbiota were greatly impacted by diet, with alpha diversity, beta diversity, and relative abundances of over 40 bacterial genera being different among treatments. This study shows that dietary format may lead to great differences in nutrient digestibility and fecal characteristics, metabolites, and microbiota. More research is needed to distinguish the effects of ingredient source, processing method, and nutrient composition.

Management Effects on Gastrointestinal Disease in Red Wolves (Canis rufus) Under Human Care: A Retrospective Study

Red wolves (Canis rufus) are the most critically endangered wolf globally, with over 95% of individuals living under human care. Gastrointestinal (GI) disease is one of the leading causes of death among adult red wolves under human care, yet links between management practices and this condition remain unclear. By integrating studbook data, survey-based husbandry information, veterinary records, and necropsy reports, our study explored the relationships between management practices and post-mortem diagnoses of GI mucosal disease among 36 adult red wolves between 2004 and 2022. For final diets fed for a minimum of 4 months before death, we report that wolves fed diets limited to only kibble were more likely to exhibit a greater severity of GI mucosal disease than those fed diets that integrated whole prey or other meat items. In addition, while living at their final facilities for a minimum of 9 months before death, wolves treated with a nonsteroidal anti-inflammatory drug exhibited more severe GI issues than those who were not. Conversely, we found no effect of housing and life history traits on GI health. This study highlights the importance of evaluating management and veterinary protocols on red wolf GI health.

Current Status of Non-Thermal Sterilization by Pet Food Raw Ingredients

Recently, as the concept of pet food that satisfies both nutritional needs and the five senses has evolved, so too has the demand for effective pet food non-thermal sterilization methods. Prominent non-thermal technologies include high-pressure processing, plasma, and radiation, which are favored for their ability to preserve nutrients, avoid residues, and minimize compositional changes, thereby maintaining quality and sensory properties. However, to assess their effectiveness on pet food, it is essential to optimize operational parameters such as pressure levels, plasma intensity, radiation dosage, and temperature. Further studies are needed to evaluate microbial sterilization efficacy and sensory attributes. This exploration is expected to lay the groundwork for preventing zoonotic diseases and improving the production of high-quality pet food.

Extruded canine diets containing primarily peas in contrast to those containing lamb and chicken meal are at higher risk of mold and mycotoxin contamination when treated similarly: An observational study

Three extruded dog diets were created for a nutritional study with different primary protein sources (BAS: lamb meal (LM) and deboned lamb (DL); CHK: chicken meal, LM, and DL; PEA: dried ground pea, LM, and DL). All diets were processed using the same single-screw extruder, shipped from the processing facility on the same day, and transported under the same conditions in January 2021. After 8 months of storage in a temperature and humidity-controlled room in September 2021, only the PEA diet was molded upon inspection. Mold and mycotoxin analysis of all diets was conducted in both September 2021 and at expiry in January 2022, which confirmed mold and mycotoxin contamination to some degree in all diets and most pronounced in the PEA diet across both timepoints. Nutrient analysis of all diets was conducted at production and 2 months post-expiry in March 2022. As expected, fatty acid and vitamin contents of all diets decreased between sampling timepoints, and amino acid contents generally remained stable. Methionine decreased by 14% in CHK, cystine decreased by 15% and 20% in CHK and PEA, respectively, tyrosine decreased by 30%, 25%, and 27% across BAS, CHK, and PEA, respectively, and taurine decreased by 50%, 42%, and 55% across BAS, CHK, and PEA, respectively. Inaccurate measurement of the PEA diet moisture content post-production likely led to mold development which may also negatively impact the availability of nutrients and could put dogs at risk for mycotoxicosis and nutrient deficiencies if not closely monitored, but controlled studies are required.

Chicken meal is not an appropriate reference protein for estimating protein quality of ingredients used in extruded diets intended for dogs

The indicator amino acid oxidation (IAAO) method has been used to determine metabolic availability (MA) of amino acids in feedstuffs for pigs, humans, and preliminarily for cats. Peas are a commonly used protein source in grain-free extruded dog diets. However, peas have a poor sulfur amino acid (AA) ratio (methionine [Met]:cysteine) with Met being the first limiting AA. Furthermore, little is known about the MA of Met in peas fed to dogs. Therefore, our objective was to compare the MA of Met in peas to chicken meal (CM), as a gold-standard reference protein. The study was done as a replicated 5 × 5 complete Latin square design. Ten neutered male mixed-breed dogs (1.5 years old; 26.0 kg ± 2.4 kg body weight; BW) fed to maintain ideal BW received all dietary treatments: BAS: lamb-based diet (deboned lamb and lamb meal) providing Met at 50% of its requirement (0.27 g/100g dry matter [DM]), CHK: CM and lamb-based diet, and PEA: ground dried pea and lamb-based diet both providing Met at 68% of its requirement (0.35 and 0.37 g/100g DM, respectively). Two other treatments were created by blending BAS with PEA (BAP) and the BAS with CHK (BAC) to create diets with Met at 59% of requirement (0.32 and 0.31 g/100g DM, respectively). This resulted in three graded levels of Met for both CM and peas to allow for a slope-ratio assay approach to quantify MA with the BAS diet as the common first point. All other AAs were provided to meet at least 120% of the AAFCO recommendations for adult dogs. The BAS diet, with supplemental DL-Met, was fed for a 2-wk wash-in period. After 2 d of diet adaptation IAAO was performed. Dogs were fed 13 small meals where meal 6 contained a priming dose (9.4 mg/kg BW) of L-[1-13C]-phenylalanine (Phe; 99%) as well as a constant dose (2.4 mg/kg BW) in meals 6-13. Breath samples were collected and enrichment of 13CO2 was measured using isotope-ratio mass spectrometry to calculate the rate of Phe oxidation (F13CO2 umol/kg BW/h). Oxidation was analyzed via SAS using PROC GLIMMIX with dog and period as random effects, and diet, %Met, and their interaction as fixed effects. Unexpectedly, the slope of Phe oxidation, in response to increasing Met intake, from CM was 31% of that of peas, indicating a lower MA for Met in CM as compared to peas. This finding may be due to damage of AAs during rendering. At this time, CM in extruded diets is not an acceptable reference protein to determine MA of AAs in dogs, and the MA of Met from peas cannot be confidently assessed.