Sustainability and Pet Food: Is There a Role for Veterinarians?

Lentils pasta by-product in a complete extruded diet for dogs and its effect on extrusion, digestibility, and carbohydrate metabolism

Introduction

Recently, increasing effort has been directed toward environmental sustainability in pet food. The aim of this study was to evaluate the extrusion parameters, nutrient digestibility, fecal characteristics, palatability and insulinemic and glycaemic curves of a complete diet for dogs in which the main carbohydrate source was a red lentil pasta by-product (LP).

Methods

Five experimental diets were formulated: a basal diet (CO) based on rice and a poultry by-product meal; three experimental diets where LP substituted rice at 33, 66, or 100% (LP33, LP66, and LP100, respectively); and a diet formulated on 70% of the basal diet (CO) plus 30% LP (LPS) to evaluate the digestibility of LP ingredient.

Results and discussion

The extruder pressure, hardness and bulk density of the kibble increased in a linear manner with increasing LP percentage (P < 0.05), without affecting starch gelatinization. According to polynomial contrast analysis, rice replacement with LP at 33 and 66% caused no reduction in apparent total tract digestibility coefficient (ATTDC), with similar or higher values compared with the CO diet. Nitrogen balance did not change (P > 0.05), but we observed a linear increase in feces production and moisture content as the LP inclusion rate rose and a linear decrease in feces pH (P < 0.05). Nevertheless, the fecal score was unaffected. Fecal acetate, propionate, total short-chain fatty acids (SCFA), branched-chain fatty acids, and lactate all increased linearly as the LP inclusion rate increased (P < 0.05), without altering ammonia concentration in feces. Feces concentrations of cadaverine, tyramine, histamine, and spermidine also increased in a linear manner with increasing LP inclusion (P < 0.05). The fermentation of LP dietary fiber by the gut microbiota increased the concentration of desirable fermentation by-products, including SCFA and spermidine. The post-prandial glucose and insulin responses were lower in the dogs fed the LP100 diet compared with CO, suggesting the possible use of this ingredient in diets designed to generate a low glycaemic response. Finally, the palatability study results showed a preference for the LP100 ration in both the "first choice" and the "consumption rate" evaluation (P < 0.05). This trial reveals how a by-product discarded from the human-grade food chain retains both its nutritional and organoleptic properties.

Domestic dogs maintain clinical, nutritional, and hematological health outcomes when fed a commercial plant-based diet for a year

Domestic dogs can maintain health on complete and well-balanced canine plant-based nutrition (K9PBN). Novel insight on health outcomes in dogs consuming K9PBN is of relevance to veterinary professionals and consumers given a growing interest in non-traditional dog foods with perceived health benefits, while considering potential safety concerns. We aimed to investigate nutritional equivalence by measuring clinical health outcomes in adult dogs fed K9PBN over twelve months compared to a meat-based diet at baseline. We enrolled fifteen clinically healthy adult dogs living in households in Los Angeles County, California in a prospective cohort study and evaluated clinical, hematological, and nutritional parameters in dogs at 0, 6, and 12 months, including complete blood count (CBC), blood chemistry, cardiac biomarkers, plasma amino acids, and serum vitamin concentrations. The study found that clinically healthy, client-owned, adult dogs maintain health, based on physical exams, complete blood count, serum chemistry, plasma amino acids, serum vitamins, and cardiac biomarkers combined with client-reported observations, when fed commercial K9PBN over a twelve-month period. This study is the most comprehensive and longest known K9PBN investigation to date and provides clinically relevant evidence-based nutrition data and new knowledge on outcomes in clinically healthy dogs who thrive without consumption of animal-derived ingredients. These results also provide a valuable foundation for the future study of K9PBN as a potential nutritional intervention for clinically relevant pathologies in canine medicine. Lastly, it is of major relevance to One Health paradigms since ingredients produced independent of industrial food animal production are both more sustainable and help to circumvent ethical dilemmas for maintenance of health in domestic dogs.

Insights to Study, Understand and Manage Extruded Dry Pet Food Palatability

Pet food production is a fast-growing industry. While extruded dry pet food is the favored pet food due to its convenience of use, it may have poorer palatability than other pet foods such as wet pet foods. However, palatability plays a pivotal role in meeting nutritional requirements or providing therapeutic benefits in cats and dogs, as it ensures food acceptance. Thus, both academics and manufacturers conduct routine palatability tests to assess acceptance and preference of products among pets, alongside sensory analyses involving human panels. Palatability is greatly influenced by species-specific and environmental factors in cats and dogs. The review will hence present the current knowledge on palatability assessment and animal food perception; it will then aim to explore strategies for effectively managing palatability in dry pet food by examining the impact of key ingredients and process parameters on the finished product's palatability. Moreover, the demands and needs for sustainable and healthier products as well as supply constraints present novel challenges and opportunities for academics and manufacturers.

A Model for Consumer Acceptance of Insect-Based Dog Foods among Adult UK Dog Owners

The use of alternative proteins is becoming more common in pet feed, and insect-based dog foods (IBDFs) are becoming more widely available. However, little research has been conducted to date in respect of the drivers for consumers' acceptance of IBDF. This study aimed to investigate the acceptance of IBDF among adult UK dog owners and the factors influencing the decision to try and buy such products. A theoretical model was developed following a review of the existing literature. An online survey of 280 participants was carried out and the results were analysed using structural equation modelling (SEM) to test the theoretical model. The following constructs all had a significant impact on attitudes towards IBDF and/or intentions to try and buy IBDF: food preferences for animal welfare, health and environment; attitudes towards uses of animals; beliefs about insect sentience; disgust; perceptions of benefits and risks; and social norms. Social norms had the strongest influence of any single construct. Consumer acceptance of IBDF is multi-faceted including social, cultural and ethical components, and it is likely that the better availability of information and opportunities for consumers to familiarise themselves with IBDF would help to drive consumer acceptance. In order to allow dog owners to make informed decisions in line with their ethical preferences, further research is needed to establish the overall health and welfare implications of IBDF on the animals involved in production, as well as the companion animals, who are the ultimate consumers.

Evaluation of Soybean Ingredients in Pet Foods Applications: Systematic Review

Soybean use has been low in pet foods, even though they are an excellent source of protein, polyunsaturated fatty acids, and gut fermentable fibers. The purpose of this evaluation was to conduct a systematic review of the public literature to explore how soybeans have been researched for pet food applications since 2000 and to provide strengths, weaknesses, opportunities, and threats for soybeans in the pet food industry. The review covered a total of 44 articles related to soybean ingredients and their potential value in the pet food arena. The articles were categorized by their research contents and narratively summarized to demonstrate useful information to both the pet and soybean industries. When soybean-based products have been adequately processed to reduce the antinutritive factors, they are comparable to processed animal proteins in nutritional value, palatability, and functionality in pet food processing. We conclude that various food processing technologies and the versatility of soybean ingredients allow soybean to have considerable inclusion potential in pet foods. More research on dietary soybean ingredients regarding pet food processing, fermentation benefits on health, and consumer acceptance will be needed to understand soybean's position in the future pet food industry.

Application of encapsulated and dry-plated food acidulants to control Salmonella enterica in raw meat-based diets for dogs

There is an increasing demand for raw meat-based diets (RMBDs) for dogs, but these foods cannot be heat-pasteurized. Thus, the objective of this study was to evaluate the antimicrobial efficacy of encapsulated and dry-plated glucono delta lactone (GDL), citric acid (CA), and lactic acid (LA) when challenged against Salmonella enterica inoculated in a model raw meat-based diet (RMBDs) for dogs. Nutritionally complete, raw diets were formulated with different levels (1.0, 2.0 and 3.0% (w/w)) of both encapsulated and dry-plated GDL, CA, and LA with both the positive (PC) and the negative controls (NC) without acidulants. The diets were formed into patties of ∼100 g and inoculated with 3-cocktail mixtures of Salmonella enterica serovars, excluding the NC to achieve a final concentration of ∼6.0 Log CFU/patty. Microbial analyses were performed on the inoculated diets and survivors of S. enterica enumerated. Both encapsulated and dry-plated CA and LA had higher log reductions compared to GDL (P < 0.05). However, encapsulated CA and LA at 1.0% (w/w) exhibited higher log reductions (P > 0.05) and preserved product quality compared to the dry-plated acidulants at 1.0%. We concluded that 1.0% (w/w) of encapsulated citric or lactic acids could be successfully applied as an antimicrobial intervention in raw diets for dogs.

Impacts of vitamin premix and/or yeast ingredient inclusion in a canned cat food on thiamin retention during 6 months of storage

Introduction

Low thiamin levels in thermally processed canned cat foods are concerning for the pet food industry. However, there is little information on storage stability of thiamin in this food format or if inclusion of select ingredients, such as dried yeasts, has an effect. Therefore, the objective was to evaluate the storage stability of thiamin when a vitamin premix and/or yeasts ingredients were included in a canned cat food.

Materials and methods

The factorial treatment arrangement consisted of 2 levels of vitamin premix (with or without) and 4 inclusions of yeast (NY = none, LBV = Lalmin B Complex Vitamins, BY = product #1064B, or EA = BGYADVANTAGE). Diets were stored for 6 months and analyzed every month for thiamin. Data were analyzed as a mixed model (SAS v. 9.4; SAS Institute, Cary, NC) with fixed effects (vitamin premix, yeast, time, and their two-way and three-way interactions) and random effects (production day and the interaction of production day, vitamin premix, and yeast). Significance was set at P < 0.05 and Fisher's LSD was used to separate means.

Results and discussion

Diets including the vitamin premix [average 55.1 mg/kg dry matter basis (DMB)] contained more (P < 0.05) thiamin than diets that did not (average 7.5 mg/kg DMB). Inclusion of LBV (average 40.3 mg/kg DMB) resulted in the highest (P < 0.05) levels of thiamin, followed by BY (P < 0.05; average 26.9 mg/kg DMB). Diets with NY and EA contained the lowest (P < 0.05) levels of thiamin and were not different from each other (P > 0.05; average 19.3 mg/kg DMB). The diet containing vitamin premix without yeast lost (P < 0.05) 17.8% thiamin while diets containing a yeast ingredient maintained thiamin levels better during storage. This suggested that thiamin from yeast ingredients was more resistant to degradation during storage and should be considered when designing new canned cat foods.

Evaluation of graded levels of corn-fermented protein on stool quality, apparent nutrient digestibility, and palatability in healthy adult cats

Dried distillers' grains, coproducts from the ethanol industry, may provide sustainable ingredients for pet food. Due to new post-fermentation separation techniques, corn-fermented protein (CFP) is higher in protein and lower in fiber compared with traditional dried distillers' grains, increasing its appeal for inclusion into pet food. Therefore, the objectives of this study were to determine the effects of increasing levels of CFP on stool quality, apparent total tract digestibility (ATTD), and palatability in adult cats. Four extruded diets were fed to 11 adult cats in an incomplete 4 × 4 replicated Latin square design. The control diet contained 15% soybean meal (0C) and CFP was exchanged for soybean meal at either 5%, 10%, or 15% (5C, 10C, 15C). Cats were fed each dietary treatment for 9-d adaption followed by 5-d total fecal collection. Feces were scored on a 1 to 5 scale, with 1 representing liquid diarrhea and 5 representing hard pellet-like (Carciofi et al., 2008). A fecal score of 3.5 to 4 was considered ideal. Titanium dioxide was added to all diets (0.4%) as a marker to estimate digestibility. Data were analyzed using a mixed model in SAS (version 9.4, SAS Institute, Inc., Cary, NC) with treatment as a fixed effect and cat and period as random effects. Fecal dry matter percent and dry fecal output were greater (P < 0.05) at elevated levels of CFP. Stool scores were maintained (P > 0.05) throughout treatments (average; 4). Dry matter, organic matter, crude protein, and gross energy ATTD decreased when cats were fed 15C. There was no difference in ATTD of fat or total dietary fiber among treatments. For palatability assessment, cats preferred 5C over 0C but had no preference with increased CFP inclusion. These results suggest that CFP is comparable to SBM, but there may be a maximum inclusion level of 10% when fed to cats.

Effects of poultry by-products inclusion in dry food on nutrient digestibility and fecal quality in Beagle dogs

Animal by-product meals show large variability in diet digestibility. This study aimed to provide information on including bone protein meal (BPM) or feather meal (FM) in extruded dog diets with regard to digestibility and fecal characteristics in two trials. In the first trial, compared to the control (BPM0), 6, 12, and 24% of the basic diets were replaced by BPM (BPM6, BPM12, and BPM24, respectively). In the second trial, in comparison to the control (FM0), 5, 10, and 20% of the basic diets were replaced by FM (FM5, FM10, and FM20, respectively). In both trials, six Beagle dogs (BW 17.3±2.14 and 18.1±2.04 kg for trials 1 and 2, respectively) participated in a crossover experiment design. Five days were used as wash-out before each experimental period for each trial. The fecal consistency scores were based on a 5-point scale (1 = very hard, 2 = solid, well formed "optimum", and 5 = watery diarrhea). In the first trial, results showed that the apparent digestibility of dry matter, crude protein, and crude fat was significantly lower for dogs fed BPM6 compared to those fed BPM24. There was a lower number of dogs with a fecal consistency score value > 2 (16.7%) among those fed BPM6 (median = 2, Interquartile range (IQR) = 0) compared to those fed BPM24 (83.3%). The fecal dry matter content was significantly (p < 0.05) the highest (39.4%±2.15) for dogs fed BPM6. In the second trial, the data revealed that dogs fed FM0 had significantly (p < 0.05) the highest organic matter digestibility (87.2%±1.05), while dogs fed FM20 had significantly (p < 0.05) the lowest crude fat digestibility (95.0%±0.95). Inclusion of FM at 10% or 20% in the diet decreased fecal dry matter significantly (29.0%±2.10 and 27.9%±2.46, respectively) compared to those animals offered FM0 (31.1%±2.56). Among those dogs fed FM0 and FM5, there was a lower significant number of dogs with a fecal score value > 2 (16.7% and 16.7%, respectively; p < 0.05). While the fecal score was significantly a higher (median = 4, IQR = 0) for dogs fed FM20. Including FM at any level in the diet resulted in significantly higher levels of iso-butyric and iso-valeric acids compared to FM0. These findings in both trials suggest that apparent crude protein digestibility was not affected when diets containing BPM up to 24% and FM up to 20% were offered, but fecal quality was reduced.

A review of food additives to control the proliferation and transmission of pathogenic microorganisms with emphasis on applications to raw meat-based diets for companion animals

Raw meat-based diets (RMBDs) or sometimes described as biologically appropriate raw food (BARFs) are gaining in popularity amongst dog and cat owners. These pet guardians prefer their animals to eat minimally processed and more “natural” foods instead of highly heat-processed diets manufactured with synthetic preservatives. The market for RMBDs for dogs and cats is estimated at $33 million in the United States. This figure is likely underestimated because some pet owners feed their animals raw diets prepared at home. Despite their increasing demand, RMBDs have been plagued with numerous recalls because of contamination from foodborne pathogens like Salmonella, E. coli, or Campylobacter. Existing literature regarding mitigation strategies in RMBD's for dogs/cats are very limited. Thus, a comprehensive search for published research was conducted regarding technologies used in meat and poultry processing and raw materials tangential to this trade (e.g., meats and poultry). In this review paper, we explored multiple non-thermal processes and GRAS approved food additives that can be used as potential antimicrobials alone or in combinations to assert multiple stressors that impede microbial growth, ultimately leading to pathogen inactivation through hurdle technology. This review focuses on use of high-pressure pasteurization, organic acidulants, essential oils, and bacteriophages as possible approaches to commercially pasteurize RMBDs effectively at a relatively low cost. A summary of the different ways these technologies have been used in the past to control foodborne pathogens in meat and poultry related products and how they can be applied successfully to impede growth of enteric pathogens in commercially produced raw diets for companion animals is provided.

Evaluation of Torula yeast as a protein source in extruded feline diets

The objective of this work was to evaluate the use of a Torula yeast (TY) on diet processing, palatability, and total tract nutrient digestibility in extruded feline diets. Four dietary treatments were compared, differing by protein source: TY, pea protein concentrate (PP), soybean meal (SM), and chicken meal (CM). Diets were produced using a single-screw extruder under similar processing conditions. Palatability assessment was conducted as a split plate design where both first choice and intake ratio (IR) were determined. Apparent total tract digestibility (ATTD) of nutrients was estimated using Titanium dioxide as an indigestible marker. During diet production, specific mechanical energy of TY and SM (average of 187 kJ/kg) was greater (P < 0.05) than for PP (138 kJ/kg); however, CM was similar to all treatments (167 kJ/kg). Kibble diameter, piece volume, and sectional expansion ratio were greatest for TY (P < 0.05). Additionally, both bulk and piece density were lowest (P < 0.05) for TY. Kibble hardness was lower for TY and SM (P < 0.05; average of 2.10 Newtons) compared to CM and PP (average of 2.90 Newtons). During the palatability trial, TY was chosen first a greater number of times than CM (P < 0.05; 36 vs. 4, respectively), but differences were not found between TY and PP (25 vs. 15, respectively) or TY and SM (24 vs. 16, respectively). Cats had a greater IR (P < 0.05) of TY compared to CM and PP (0.88 and 0.73, respectively). However, there was no difference in preference between TY and SM. ATTD of dry matter (DM) and organic matter (OM) was greater (P < 0.05) for CM (87.43% and 91.34%, respectively) than other treatments. Both DM and OM ATTD of TY were similar (P < 0.05) to PP and SM (average of 86.20% and average of 89.76%, respectively). Ash ATTD was greater (P < 0.05) for cats fed TY and SM (average of 37.42%), intermediate for PP (32.79%), and lowest for CM (23.97%). Crude protein (CP) ATTD of TY was similar to all other treatments (average of 89.97%), but fat ATTD was lower (P < 0.05; 92.52%) than other treatments (93.76% to 94.82%). Gross energy ATTD was greater (P < 0.05) for CM than TY (90.97% vs. 90.18%, respectively); however, TY was similar to PP and SM (average of 90.22%). Total dietary fiber ATTD was similar between TY and CM (average of 66.20%) and greater (P < 0.05) than PP and SM (average of 58.70%). The TY used in this study facilitated diet formation, increased diet preference, and was highly digestible when fed to cats.

Nutritional Composition and Untargeted Metabolomics Reveal the Potential of Tetradesmus obliquus, Chlorella vulgaris and Nannochloropsis oceanica as Valuable Nutrient Sources for Dogs

The growing pet population is questioning the sustainability of the pet food system. Although microalgae may constitute a more sustainable food resource, the assessment of their potential for canine diets is almost non-existent. The present study aimed to evaluate the potential of three microalgae species (Tetradesmus obliquus, Chlorella vulgaris and Nannochloropsis oceanica) grown locally in industrial photobioreactors as alternative food resources for dogs. A detailed characterization of their nutritional composition and metabolomic profile was carried out and related to the nutritional requirements of dogs. Overall, the essential amino acid content exceeded the amounts required for dogs at all life stages, except methionine and cysteine. The three microalgae were deficient in linoleic acid, N. oceanica presented a linolenic acid content below requirements and T. obliquus and C. vulgaris were deficient in arachidonic and eicosapentaenoic acids. The fiber was mainly composed of insoluble dietary fiber. The mineral profile varied greatly with the microalgae species, demonstrating their different potential for dog feeding. Untargeted metabolomics highlighted glycolipids, glycerolipids and phospholipids as the most discriminating compounds between microalgae species. Overall, the results support the potential of T. obliquus, C. vulgaris and N. oceanica as valuable macro- and micro-nutrients sources for dog feeding.

Insects as Feed for Companion and Exotic Pets: A Current Trend

The objective of this review was to carry out a comprehensive investigation of the benefits of incorporating insects as a pet food ingredient and the implications this can have in determining a market demand for insect-based pet foods. Black soldier fly larvae (Hermetia illucens), mealworm larvae (Tenebrio molitor) and adult house crickets (Acheta domesticus) are currently used in pet food. These insects are widely fed to exotic pets, mainly in whole, live or dehydrated formats. They are also incorporated as meal or fat and are offered to cats and dogs as dry or wet food and treats. Scientific studies about the use of insects for dog and cat feed are scarce. Most studies are in dogs. Research shows that insect nutrients, mainly amino acids, have high digestibility, are beneficial to health, do not have any detrimental effect on the gut microbiota and are accepted by dogs. In several countries, insects are approved for use in pet food and commercialization has spread throughout the world. Pet owners are willing to try foods made with insect meal for their pets. In conclusion, the use of insects in pet food is a reality that is taking on more and more prominence.

Unlocking the Real Potential of Black Soldier Fly (Hermetia illucens) Larvae Protein Derivatives in Pet Diets

Black soldier fly larvae (BSFL)-derived proteins are gaining popularity as sustainable pet food ingredients. According to the literature, these ingredients have strong antioxidant and antimicrobial activities. Due to the ability of BSFL protein derivatives to donate hydrogen atoms and/or electrons to counterpoise unstable molecules, they could possibly help in the prevention of osteoarthritis. During this study, the antiarthritic potential of BSFL protein derivatives was evaluated using the following assays: (1) proteinase inhibition, (2) erythrocyte membrane stability, (3) reactive oxygen species (ROS) production by activated macrophages, (4) ROS production by monocytes, and (5) cellular toxicity. Additionally, the glucosamine content of these ingredients was also evaluated. Chicken meal is commonly used in pet food formulations and was used as an industrial benchmark. The results obtained during this study demonstrated the strong antiarthritic potential of BSFL protein derivatives. We found that BSFL protein derivatives are not only useful in preventing the development of arthritis but could also help to cure it due to the presence of glucosamine. We also found that chicken meal could contribute to the development of arthritis by increasing ROS production by monocytes.