Citrus pulp and orange fiber as dietary fiber sources for dogs

Metabarcoding study of potential pathogens and zoonotic risks associated with dog feces in Seoul, South Korea

BACKGROUND

A significant portion of South Korea's population, approximately a quarter, owns pets, with dogs being the most popular choice among them. However, studies analyzing the fecal organism communities of dogs in South Korea are lacking, and limited efforts have been exerted to identify pathogens with potential zoonotic implications. Therefore, this study aimed to investigate potential pathogens using metabarcoding analysis and evaluate the risk of zoonotic diseases in dog feces in Seoul, South Korea.

METHODOLOGY

Fecal samples were collected from both pet and stray dogs in the Mapo district of Seoul. Next-generation sequencing (NGS) was utilized, employing 16S rRNA amplicon sequencing to identify prokaryotic pathogens, and 18S rRNA amplicon sequencing for eukaryotic pathogens. The data obtained from the QIIME2 pipeline were subjected to various statistical analyses to identify different putative pathogens and their compositions.

PRINCIPAL FINDINGS

Significant variations in microbiota composition were found between stray and pet dogs, and putative prokaryotic and eukaryotic pathogens were identified. The most prevalent putative bacterial pathogens were Fusobacterium, Helicobacter, and Campylobacter. The most prevalent putative eukaryotic pathogens were Giardia, Pentatrichomonas, and Cystoisospora. Interestingly, Campylobacter, Giardia, and Pentatrichomonas were found to be significantly more prevalent in stray dogs than in pet dogs. The variation in the prevalence of potential pathogens in dog feces could be attributed to environmental factors, including dietary variances and interactions with wildlife, particularly in stray dogs. These factors likely contributed to the observed differences in pathogen occurrence between stray and pet dogs.

CONCLUSIONS/SIGNIFICANCE

This study offers valuable insights into the zoonotic risks associated with dog populations residing in diverse environments. By identifying and characterizing putative pathogens in dog feces, this research provides essential information on the impact of habitat on dog-associated pathogens, highlighting the importance of public health planning and zoonotic risk management.

Safety and efficacy of a feed additive consisting of an essential oil obtained from the fruit of Carum carvi L. (caraway oil) for all animal species (FEFANA asbl)

Following a request from the European Commission, EFSA was asked to deliver a scientific opinion on the safety and efficacy of an essential oil obtained from the fruit of Carum carvi L. (caraway oil), when used as a sensory additive in feed and water for drinking for all animal species. The EFSA Panel on Additives and Products or Substances used in Animal Feed (FEEDAP) Panel concluded that the use of caraway oil is of no concern up to the following concentrations in complete feed: 9 mg/kg for chickens for fattening, 13 mg/kg for laying hens, 12 mg/kg for turkeys for fattening, 16 mg/kg for piglets, 19 mg/kg for pigs for fattening, 24 mg/kg for sows, 35 mg/kg for veal calves (milk replacer), 11 mg/kg for cattle for fattening, 10 mg/kg for dairy cows, sheep, goats, horses and rabbits, 25 mg/kg for salmonids and dogs. These conclusions were extrapolated to other physiologically related species. For cats, ornamental fish and other species, no conclusion can be drawn. The use of caraway oil in animal feed under the proposed conditions of use is safe for the consumer and the environment. The additive under assessment should be considered as an irritant to skin and eyes, and as a respiratory and skin sensitiser. When handling the essential oil, exposure of unprotected users to perillaldehyde may occur. Therefore, to reduce the risk, the exposure of the users should be minimised. Since C. carvi and its preparations were recognised to flavour food and its function in feed would be essentially the same as that in food, no further demonstration of efficacy was considered necessary.

Safety and efficacy of a feed additive consisting of an essential oil obtained from the fruit of Apium graveolens L. (celery seed oil) for all animal species (FEFANA asbl)

Following a request from the European Commission, EFSA was asked to deliver a scientific opinion on the safety and efficacy of an essential oil obtained from the fruit of Apium graveolens L. (celery seed oil), when used as a sensory additive in feed and water for drinking for all animal species. The EFSA Panel on Additives and Products or Substances used in Animal Feed (FEEDAP) Panel concluded that the use of celery seed oil is of no concern up to the following concentrations in complete feed: 1.6 mg/kg for chickens for fattening, 2.3 mg/kg for laying hens, 2.1 mg/kg for turkeys for fattening, 2.8 mg/kg for piglets, 3.3 mg/kg for pigs for fattening, 4.1 mg/kg for sows, 6.5 mg/kg for veal calves (milk replacer), 6.2 mg/kg for cattle for fattening, sheep, goats and horses, 4.0 mg/kg for dairy cows, 2.5 mg/kg for rabbits, 6.8 mg/kg for salmonids and 7.2 mg/kg for dogs. These conclusions were extrapolated to other physiologically related species. For cats, ornamental fish and other species, no conclusion can be drawn. The use of celery seed oil in animals feed is not expected to pose concern for the consumers and for the environment. The additive under assessment should be considered as an irritant to skin and eyes, and as a respiratory and skin sensitiser. When handling the essential oil, exposure of unprotected users to perillaldehyde and bergapten may occur. Therefore, to reduce the risk, the exposure of the users should be minimised. Since A. graveolens and its preparations were recognised to flavour food and its function in feed would be essentially the same as that in food, no further demonstration of efficacy was considered necessary.

Modification, biological activity, applications, and future trends of citrus fiber as a functional component: A comprehensive review

Citrus fiber, a by-product of citrus processing that has significant nutritional and bioactive properties, has gained attention as a promising raw material with extensive developmental potential in the food, pharmaceutical, and feed industries. However, the lack of in-depth understanding regarding citrus fiber, including its structure, modification, mechanism of action, and potential applications is holding back its development and utilization in functional foods and drugs. This review explores the status of extraction methods and modifications applied to citrus fiber to augment its health benefits. With the aim of introducing readers to the potential health benefits of citrus fibers, we have placed special emphasis on their regulatory mechanisms in the context of various conditions, including type 2 diabetes mellitus, cardiovascular disease, obesity, and cancer. Furthermore, this review highlights the applications and prospects of citrus fiber, aiming to provide a theoretical basis for the utilization and exploration of this valuable resource.

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.

Guava fibre characterization and effects on digestibility, fermentation products, gastrointestinal transit time and palatability of dry diets for dogs

The use of fruit fibres as a way of reusing industrial waste is attractive and necessary, increasing the efficiency and reducing the environmental impact of the industry. This study characterized guava fibre as a fibrous ingredient and evaluated its effects when included in extruded diets for dogs on nutrient digestibility, faecal traits, fermentation products, gastrointestinal transit time and palatability. Four diets were formulated: CO (control diet, no fibrous ingredients added), GF3 (3% guava fibre), GF6 (6% guava fibre) and GF12 (12% guava fibre). The guava fibre was added to diets in replacement of maize, with small adjustments in the other ingredients to ensure similar contents of protein and fat. The diets were fed to 24 adult Beagle dogs (6 per diet) during 15 days for adaptation followed by 15 days for assessment of digestibility, fermentation end products and gastrointestinal transit time. The palatability of G6 and G12 treatments was evaluated against the CO by the two-pan test. Results were compared by analysis of variance and polynomial contrasts according to the guava fibre inclusion level (p < 0.05). The addition of guava fibre did not change nutrient intake except for the increase on dietary fibre (p < 0.001). Fibre inclusion resulted in a quadratic reduction in total tract apparent digestibility for dry matter, organic matter, crude protein and crude energy (p < 0.001), and on the metabolizable energy content of the foods (p < 0.001). Guava fibre addition did not change the faecal concentration of ammonia, lactic acid, faecal pH and branched chain fatty acids but it decreased acetic and propionic acids concentration (p < 0.01). The inclusion of 12% guava fibre did result in a faster transit time (p = 0.046) compared to the control diet. Guava fibre can be characterized as a novel insoluble non-fermentable fibre source that could be safely used in levels up to 12% in canine extruded diets.

The Impact of Fiber Source on Digestive Function, Fecal Microbiota, and Immune Response in Adult Dogs

This study evaluated the impact of different fiber sources on intestinal function, fecal microbiota, and overall health in dogs. Twelve dogs were used in a crossover design, involving three periods of 6 weeks and three diets: a low-fiber diet (CTR), a cereal-fiber and beet-pulp-supplemented diet (BRA), and a fruit-fiber-supplemented diet (FRU). Each period included a digestibility trial and fecal and blood sampling in the last week. Short-chain fatty acids (SCFAs) and microbiota taxonomy (16S rRNA Illumina-MiSeq) and functionality (Shotgun-NovaSeq 6000) were determined in the feces. General biochemistry, complete blood cells, and lymphocyte subsets were also analyzed. The fiber-supplemented diets showed lower digestibility without significant changes in the fecal consistency. The BRA diet showed higher total SCFA concentrations (p = 0.056), with increases in alpha diversity and particular beneficial genera, such as Lachnospira, Bifidobacterium, and Faecalibacterium. The BRA microbiota was also associated with an overabundance of genes related to carbohydrate and amino acid metabolism. The FRU diet had a distinct impact on the microbiota composition and functionality, leading to higher levels of CD8 lymphocytes. These findings emphasize the importance of selecting the right fiber source when formulating dog diets, as it can have a differential impact on gut microbiota and animal health.

Effect of Citrus Pellet on Extrusion Parameters, Kibble Macrostructure, Starch Cooking and In Vitro Digestibility of Dog Foods

Fiber supplemented extruded foods are produced by pet food companies to help with several specific health conditions. The fiber material, however, is difficult to incorporate efficiently into dry kibble diets for dogs. The aim of the study was to evaluate the influence of citrus pulp pellet (CPP), the solid waste part of the production of orange juice characterized by a good proportion of soluble and fermentable fiber, on extrusion traits, kibble macrostructure, starch gelatinization and in vitro digestibility of dog foods. A control formula (CO) was developed for dogs. CPP was added to CO at different inclusion levels: 5%, 10%, 15% and 20%. Foods were extruded in a single screw extruder using two different die diameters (d_d): 5 mm and 7 mm. CPP inclusion with 5 mm d_d did not affect bulk and piece density and resulted in a lower impact on kibble expansion; It also resulted in greater starch gelatinization and kibble expansion compared to the 7 mm d_d configuration (p < 0.01). In addition to the nutritional implications, recycling and proper uses of this material exemplified in the present study by the exploration of CPP as a fiber source to dogs, this method can improve sustainable agriculture by transforming low-quality materials into high-quality foods.

Fine cassava fibre utilization as a dietary fibre source for dogs: Effects on kibble characteristics, diet digestibility and palatability, faecal metabolites and microbiota

The objective was to evaluate through three experiments the effects of a fine cassava fibre (CA: 106 µm) on kibble characteristics, coefficients of total tract apparent digestibility (CTTAD) of macronutrients, diet palatability and faecal metabolites and microbiota of dogs. Dietary treatments consisted of a control diet (CO), without an added fibre source and with 4.3% total dietary fibre (TDF), and a diet with 9.6% CA (106 µm), with 8.4% TDF. Experiment I evaluated the physical characteristics of the kibbles. The palatability test was evaluated in experiment II, which compared the diets CO versus CA. In experiment III, 12 adult dogs were randomly assigned to one of the two dietary treatments for 15 days, totalling six replicates/treatment, to assess the CTTAD of macronutrients; faecal characteristics, faecal metabolites and microbiota. The expansion index, kibble size and friability of diets with CA were higher than the CO (p < 0.05). Additionally, the CA diet presented higher palatability than the CO (p < 0.05) but did not affect CTTAD except for those of fibre (p > 0.05). Moreover, a greater faecal concentration of acetate, butyrate and total short-chain fatty acids (SCFA) and a lower faecal concentration of phenol, indole and isobutyrate were observed in dogs fed the CA diet (p < 0.05). Dogs fed with the CA diet presented a greater bacterial diversity and richness and a greater abundance of genera considered to be beneficial for gut health, such as Blautia, Faecalibacterium and Fusobacterium when compared to the CO group (p < 0.05). The inclusion of 9.6% of a fine CA improves the expansion of kibbles and diet palatability without affecting most of the CTTAD of nutrients. Besides, it improves the production of some SCFA and modulates the faecal microbiota of dogs.

Designing Nutritious and Sustainable Biscuits Using Upcycled Fibre-Rich Ingredients Obtained by Hot Air - Microwave Drying of Orange by-Products

Circular use of resources implies developing mild processes to transform food by-products into value-added products, without using organic solvents or extensive washing and drying steps. Refined ingredients are commonly used in gluten-free bakery resulting in high levels of saturated fatty acids and sugars as well as a lack of essential nutrients like dietary fibres. The objective of this study was (i) to compare the nutritional composition and the water retention capacity (WRC) of an upcycled orange fibre dried by hot air combined with microwave (HAD+MW) and a commercial orange fibre obtained by different methods (COM), and (ii) to compare the nutritional, texture and sensory profile of gluten-free biscuits formulated with HAD+MW and with COM fibres. The total dietary fibre content (72.0 ± 3.0%) and WRC (21.1 ± 2.7 g_water/ g) of HAD+MW fibre did not differ from the nutritional composition of the control orange fibre (COM). However, for HAD+MW fibre, protein (+2.34 fold), fat (-4.75 fold), ash (-2.31 fold), sugars (-1.42 fold) and moisture content (+11.5 fold) was different from COM. Instrumental texture analysis showed that biscuits with HAD+MW fiber resulted in less hardness (26%) than those with COM fiber. However, this difference was not perceived by panellists (p > 0.05). Exterior colour, cereal, vanilla and citrus aroma-flavour, and granularity were slightly more intense in HAD+MW biscuits but still similar to the commercial control fiber. Thus, the HAD+MW drying method can be used for upcycling orange by-products, obtaining less refined and more nutritious and sustainable ingredients for fiber-enrichment of gluten-free biscuits.

Effect of orange fibre on nutrient digestibility and fermentation products in faeces of cats fed kibble diets

The aim of the present study was to compare orange fibre, beet pulp and inulin as fibre sources for cats. A control diet (CON) was formulated without inclusion of a fibre source. Further experimental diets were also based on diet CON but were supplemented with 1% orange fibre (diet 1%OF); 3% orange fibre (diet 3%OF); 3% beet pulp (diet 3%BP) or 1% inulin (diet 1%IN). Forty cats were used in a randomised block design (4 blocks of 10 cats, 2 animals per food in each block, totalling 8 animals per treatment). Each block lasted 20 d, with 10 d of adaptation, 10 d of faecal collection for digestibility as well as evaluation of pH-value and fermentation products. The digestibility of dry matter, organic matter, crude protein, ether extract, starch and gross energy did not vary between diets. In diet 1%OF, dietary fibre revealed a greater digestibility than in diet CON (p < 0.05). Faecal production was higher in cats fed diets 3%OF and 3%BP than in those fed diet 1%IN (p < 0.05). Faecal concentrations of acetate and total short-chain fatty acids were higher for cats fed diet 3%BP than for those fed diets 1%IN and CON (p < 0.05), while diets 1%OF and 3%OF showed intermediate results. Faecal propionate concentration was higher for cats fed diet 3%BP, intermediate for diets 1%OF, 3%OF and 1%IN and lower for animals fed diet CON (p < 0.05). Compared with diets CON and 1%IN, the faecal concentration of tyramine was higher for cats fed diet 3%OF (p < 0.05). Orange fibre was fermentable; up to 3% inclusion it did not interfere with the digestibility of nutrients, faecal score and faecal moisture content, and promoted the formation of short-chain fatty acids and tyramine by the intestinal microbiota, with possible effects on intestinal function.