Effects of Zinc Source and Enzyme Addition on the Fecal Microbiota of Dogs

Thermoplastic Zinc-Infused Polymer for Chairside Socket Seal Abutments Enhances Antimicrobial and Tissue-Integrative Properties

Background/Objectives: The essential trace element zinc (Zn) has a pivotal role in wound healing and can show antibacterial activity, but its application in oral implant materials is underexplored. Customized healing abutments can modulate the peri-implant tissue health when appropriate bioactive materials promoting mucosal healing are used. The present study investigated a novel Zn-containing polymer for its potential in soft-tissue engineering applications. Methods: Four traditional materials-titanium, glass ionomer, a composite, and the novel Zn-containing polymer-were tested in vitro for bacterial growth using a multispecies oral bacterial model compared to hydroxyapatite. The biocompatibility of the materials was also evaluated by evaluating the adhesion, proliferation, and cytotoxicity of human oral keratinocytes (HOK-18A) onto these materials, compared to tissue culture plastic. Results: The Zn-containing polymer exhibited a significantly lower biofilm formation compared to conventional materials as it was composed of less pathogenic bacteria. The Zn-containing material also demonstrated a superior biocompatibility towards HOK-18A, approximating the adhesion and proliferation of the keratinocytes to optimal tissue culture conditions. Moreover, these properties did not seem to degrade and were maintained over a period of 31 days. The cytotoxicity assessment revealed no significant reduction in metabolic activity for any material. Conclusions: This study highlights the potential of the novel Zn-containing polymer in soft-tissue engineering, owing to its antimicrobial and biocompatible assets. These properties, combined with the ease of chairside modeling, position the material as a promising alternative for creating customized healing abutments. Further research is needed to explore its mechanism of wound healing modulation and its clinical performance.

Associations of Stool Metal Exposures with Childhood Gut Microbiome Multiomics Profiles in a Prospective Birth Cohort Study

Metal exposures are closely related to childhood developmental health. However, their effects on the childhood gut microbiome, which also impacts health, are largely unexplored using microbiome multiomics including the metagenome and metatranscriptome. This study examined the associations of fecal profiles of metal/element exposures with gut microbiome species and active functional pathways in 8- to 12-year-old children (N = 116) participating in the GESTation and Environment (GESTE) cohort study. We analyzed 19 stool metal and element concentrations (B, Na, Mg, Al, K, Ca, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, As, Mo, Cd, Ba, and Pb). Covariate-adjusted linear regression models identified several significant microbiome associations with continuous stool metal/element concentrations. For instance, Zn was positively associated with Turicibacter sanguinis (coef = 1.354, q-value = 0.039) and negatively associated with Eubacterium eligens (coef = -0.794, q-value = 0.044). Higher concentrations of Cd were associated with lower Eubacterium eligens (coef = -0.774, q-value = 0.045). Additionally, a total of 490 significant functional pathways such as biosynthesis and degradation/utilization/assimilation were identified, corresponding to different functions, including amino acid synthesis and carbohydrate degradation. Our results suggest links among metal exposures, pediatric gut microbiome multiomics, and potential health implications. Future work will further explore their relation to childhood health.

Protein hydrolysate and oil from fish waste reveal potential as dog food ingredients

The increased fish consumption by the growing human population in the world translates into an increase in fish waste. The reintroduction of these fish by-products into food and feed chains presents economic benefits and contributes to counteracting their negative environmental impact. Under this context, the present study aimed to evaluate the effects of the dietary inclusion of fish hydrolysate and oil obtained from fish waste (experimental diet) in substitution of shrimp hydrolysate and salmon oil (control diet) mainly imported from third countries on palatability, apparent total tract digestibility, fecal characteristics and metabolites, blood fatty acid profile, flatulence, and coat quality of adult dogs. A two-bowl test was performed to evaluate palatability by the pairwise comparison between the two diets. A feeding trial was conducted according to a crossover design with two diets (control and experimental diets), six adult Beagle dogs per diet, and two periods of 6 weeks each. The replacement of shrimp hydrolysate and salmon oil with fish hydrolysate and oil did not affect the first diet approach and taste, as well as the intake ratio. Generally, the digestibility of dry matter, nutrients, and energy was not affected by diet, but the intake of digestible crude protein (CP) and ether extract was higher, respectively, with the control and the experimental diet. The higher intake of eicosapentaenoic acid and docosahexaenoic acid with the experimental diet was reflected in a higher content of these long-chain polyunsaturated fatty acids and the omega-3 index of red blood cells, but it did not affect coat quality. The significantly higher intake of digestible CP with the control diet might have contributed to the higher fecal ammonia-N and valerate concentrations. Daily fecal output and characteristics were similar between diets. Overall, results suggest that fish hydrolysate and oil from the agrifood industry might constitute sustainable functional ingredients for dog feeding while adding value for wild fisheries, aquaculture, and fish farming under a circular economy approach and reducing dependence on imports from third countries with a high carbon footprint.

Squid meal and shrimp hydrolysate as novel protein sources for dog food

The world's growing pet population is raising sustainability and environmental concerns for the petfood industry. Protein-rich marine by-products might contribute to mitigating negative environmental effects, decreasing waste, and improving economic efficiency. The present study evaluated two marine by-products, squid meal and shrimp hydrolysate, as novel protein sources for dog feeding. Along with the analysis of chemical composition and antioxidant activity, palatability was evaluated by comparing a commercial diet (basal diet) and diets with the inclusion of 150 g kg-1 of squid meal or shrimp hydrolysate using 12 Beagle dogs (2.2 ± 0.03 years). Two in vivo digestibility trials were conducted with six dogs, three experimental periods (10 days each) and three dietary inclusion levels (50, 100 and 150 g kg-1) of squid meal or shrimp hydrolysate in place of the basal diet to evaluate effects of inclusion level on apparent total tract digestibility (ATTD), metabolizable energy content, fecal characteristics, metabolites, and microbiota. Both protein sources presented higher protein and methionine contents than ingredients traditionally used in dog food formulation. Shrimp hydrolysate showed higher antioxidant activity than squid meal. First approach and taste were not affected by the inclusion of protein sources, but animals showed a preference for the basal diet. Effects on nutrient intake reflected the chemical composition of diets, and fecal output and characteristics were not affected by the increasing inclusion levels of both protein sources. The higher ATTD of dry matter, most nutrients and energy of diets with the inclusion of both by-products when compared to the basal diet, suggests their potential to be included in highly digestible diets for dogs. Although not affected by the inclusion level of protein sources, when compared to the basal diet, the inclusion of squid meal decreased butyrate concentration and shrimp hydrolysate increased all volatile fatty acids, except butyrate. Fecal microbiota was not affected by squid meal inclusion, whereas inclusion levels of shrimp hydrolysate significantly affected abundances of Oscillosperaceae (UCG-005), Firmicutes and Lactobacillus. Overall, results suggest that squid meal and shrimp hydrolysate constitute novel and promising protein sources for dog food, but further research is needed to fully evaluate their functional value.

Unveiling the effects of shrimp hydrolysate as a dietary ingredient in healthy adult Beagle dogs

To be more sustainable, the pet food industry could increase the inclusion of animal byproducts from the human food chain and fish hydrolysates have been reported to benefit dogs' health. However, there is limited research on the impact of alternative marine hydrolysates in dog food. The current study evaluated the effects of including shrimp hydrolysate as a replacement for wheat gluten (experimental diet) in an extruded complete diet (control diet) on diet palatability, intake, digestibility, fecal characteristics and metabolites, oral volatile sulfur compounds (VSC), and coat quality in dogs. The palatability of diets was assessed in a 2-bowl test, conducted with 12 healthy adult Beagle dogs. No differences were observed in the first approach, first taste, or intake ratio. A randomized block design lasting 12 wk was performed with 12 dogs distributed into 6 blocks, according to sex and body weight; one dog from each block was randomly allocated to each diet. Fecal characteristics and metabolites were measured in weeks 0, 4, 8, and 12, VSC and coat quality in weeks 4, 8, and 12, and apparent total tract digestibility (ATTD) of nutrients and energy in week 12. The inclusion of shrimp hydrolysate did not affect intake, but increased fecal output (dry matter, DM, basis, P < 0.05). Fecal butyrate concentration was lower (P < 0.05) in dogs fed the experimental diet. The inclusion of shrimp hydrolysate did not affect ATTD of nutrients and energy, and VSC. Both diets promoted high coat quality. The experimental diet decreased gloss and general evaluation scores in week 4 (P < 0.05), but improved scale scores in weeks 4 and 12 (P < 0.05). Overall, the findings indicate the potential of including shrimp hydrolysate in diets for dogs, fostering a more sustainable industry.

The Effect of Sodium Alginate-Coated Nano-Zinc Oxide on the Growth Performance, Serum Indexes and Fecal Microbial Structure of Weaned Piglets

High dose of zinc oxide (ZnO) could improve growth performance and alleviate disease status, whereas it caused serious environmental pollution and bacterial resistance. This study was to investigate whether low doses of sodium alginate-coated nano zinc oxide (saZnO), a new type of zinc resource, could serve as a potential alternative to pharmacological doses of traditional ZnO in weaned piglets. A total of 144 crossbred piglets were randomly allocated into three groups, including a basal diet without the addition of Zn (CON), a basal diet with 1600 mg Zn/kg from traditional ZnO (ZnO), and a basal diet with 500 mg Zn/kg from saZnO (saZnO). The experiment lasted for 28 days. The results showed that supplementing with ZnO and saZnO for 14 and 28 days significantly improved body weight (BW) and average daily gain (ADG) (p < 0.01) and markedly reduced the feed intake-to-gain ratio (F/G) (p < 0.05) and diarrhea rate. In addition, dietary ZnO and saZnO significantly increased the activities of the total antioxidant capacity (T-AOC) and alkaline phosphatase (ALP) (p < 0.01). Supplementing with saZnO also promoted the levels of superoxide dismutase (SOD), IgM and copper- and zinc-containing superoxide dismutase (Cu/Zn-SOD) in serum (p < 0.05), whereas a ZnO addition decreased the concentration of malondialdehyde (MDA) (p < 0.05), indicating the beneficial effect of Zn on antioxidant and immune functions. Piglets fed the ZnO diet showed higher serum Zn accumulations than those fed the CON and saZnO diets at d 28 (p < 0.01), and supplementing with ZnO and saZnO markedly contributed to Zn excretion in feces, especially in the ZnO diet (p < 0.01). Additionally, piglets fed the saZnO diet had greater valeric acid concentrations (p < 0.05) in their feces, while other short chain fatty acids (SCFAs) were not affected by different treatments (p > 0.05). Microbial alpha diversity was reduced in the saZnO group compared with the CON group (p < 0.05), while an obvious separation of microbial composition, the marker of beta diversity, was shown among the three groups (p < 0.05). At the genus level, six genera, including Clostridium_sensu_stricto_1, Terrisporobacter, f_Muribaculaceae, Subdoligranulum and Intestinibacter, were pronouncedly increased in the ZnO and saZnO groups (p < 0.05); another nine species were dramatically downregulated, such as f_Lachnospiraceae, f_Prevotellaceae, f_Butyricicoccaceae and f_Ruminococcaceae (p < 0.05). Finally, a functional analysis indicated that altered microbes significantly changed the "Metabolism" pathway (p < 0.05). These findings suggested that saZnO could act as a feasible substitute for ZnO to reduce Zn emission and enhance growth performance, antioxidant and immune functions, and to adjust the structure of gut microbiota in piglets.

Effects of microalgae as dietary supplement on palatability, digestibility, fecal metabolites, and microbiota in healthy dogs

The current trend of dog owners increasingly favoring the functional value of food to assure preventive health and wellbeing of their pets has been raising the interest in microalgae as natural additives with bioactive properties. However, scientific studies addressing the effects of microalgae supplementation in diets for dogs are scarce. This study aimed to evaluate the effects of dietary supplementation with three microalgae species (Chlorella vulgaris, Nannochloropsis oceanica, and Tetradesmus obliquus) on diet palatability, total tract digestibility, metabolizable energy content, fecal metabolites and microbiota of dogs. Twelve adult Beagle dogs were used in three two-bowl tests to compare the palatability of a commercial complete diet for adult dogs without (reference diet) and with 1.5% supplementation of each microalgae. From the results obtained, three digestibility trials were performed according to a replicated Latin square 3 × 3, with six adult Beagle dogs, three experimental periods of 10 days each, and three dietary supplementation levels of microalgae (0.5, 1.0, and 1.5%). In each trial, effects of microalgae supplementation levels on total tract digestibility, metabolizable energy content, fecal metabolites and microbiota of dogs were evaluated. First diet approached or tasted was not significantly affected by microalgae inclusion, but dogs showed a preference for the reference diet over the diets with 1.5% inclusion of C. vulgaris and N. oceanica, no difference being observed with 1.5% T. obliquus. In all digestibility trials, dietary supplementation with microalgae up to 1.5% did not greatly affected the dietary chemical composition and kept unaffected food intake, fecal output and metabolites, and digestibility of nutrients and energy. Compared with the reference diet, supplementation with C. vulgaris increased protein digestibility. Fecal characteristics and metabolites were affected by microalgae supplementation, being the effects dependent on the species. Fecal microbiota composition of dogs fed with microalgae-supplemented diets was modified by promoting the beneficial Turicibacter and Peptococcus genera associated with gut health and activation of the immune system. Overall, the results support C. vulgaris, N. oceanica, and T. obliquus as sustainable functional supplements that potentially enhance gastrointestinal health of dogs through the selective stimulation of microbiota without detrimental effects on food intake and digestibility.