Enhanced omega-3 index after long- versus short-chain omega-3 fatty acid supplementation in dogs

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.

Technological Benefits Associated with the Use of Spray-Dried Animal Plasma in Fish-Based Chunks for Canned Pet Food

Spray-dried animal plasma (SDAP) and wheat gluten (WG) are common binders in wet pet food that provide amino acids and energy, as well as texture and cohesiveness due to their gelling strength, water retention and fat emulsion properties. Binder use is a valuable tool especially in recipes based on ingredients with low technological properties such as fish by-products containing spines and scales and soft texture after cooking. Two basal recipes for chunks in gravy were produced to evaluate experimental treatments. One basal recipe used a mixture of salmon and tuna by-products as the only animal protein sources without binders or with a 20 g/kg inclusion of SDAP or WG. The other basal recipe mimicked a more typical commercial recipe containing meat animal ingredients and a 40 g/kg salmon by-product to develop experimental treatments with and 0, 10, 20, 30 or 40 g/kg inclusions of SDAP. Dry matter, protein, and viscosity were evaluated in raw emulsions. After a 1 h retorting at 121 °C, hardness was measured in emulsions and in cooked chunks, juiciness, and Texture Profile Analysis (TPA) were assessed. Results demonstrated the viability of producing quality chunks in gravy containing only fish by-products including 20 g/kg of SDAP, which significantly increased hardness, elasticity, cohesiveness, and juiciness. There was a positive linear correlation of increased SDAP inclusion rate in the commercial recipe for most of the quality parameters evaluated. Based on these results, the inclusion of SDAP in fish recipes can help manufacturers achieve technological quality control targets for commercial wet pet food and may help producers to successfully formulate new recipes for wet pet food products using fish by-products as the sole animal protein source.

Effect of dietary krill oil supplementation on horse red blood cell membrane fatty acid composition and blood parameters

Supplementation with marine-derived n-3 long-chain polyunsaturated fatty acids (LC PUFAs), eicosapentaenoic acid (EPA, 20:5 n-3) and docosahexaenoic acid (DHA, 22:6 n-3) is linked to beneficial health effects in both humans and horses. Krill oil (KO), which is extracted from the Antarctic krill (Euphausia superba), is well documented as a safe and biologically available dietary supplement in humans and several animal species, but there is a lack of documentation regarding its effect as a dietary ingredient for horses. The objective of this study was to test whether KO as a dietary supplement had the ability to raise horse red blood cell (RBC) membrane EPA and DHA, expressed as the n-3 index. Five nonworking Norwegian cold-blooded trotter horse geldings (body weight [BW]: 567 ± 38 kg) were supplemented with KO (10 mL/100 kg BW) for 35 days in a longitudinal study. Blood samples were analysed for RBC membrane fatty acid (FA) profile, haematology and serum biochemistry every 7th day. KO was well accepted by all horses, and no adverse health effects were observed during the 35-day trial period. KO supplementation affected the RBC membrane FA profile by increasing the n-3 index from Day 0 to 35 (Day 0: 0.53% vs. Day 35: 4.05% of total RBC FAs). The observed increase in the sum of EPA and DHA (p < 0.001), total n-3 FAs (p < 0.001) and the reduction of n-6 FAs (p < 0.044) resulted in a lower n-6:n-3 ratio (p < 0.001) by Day 35 of KO supplementation. In conclusion, the RBC n-3 index was increased and the general n-6:n-3 ratio was decreased in horses receiving 35-day dietary KO supplementation.

Phospholipid Fatty Acid Profiles of Plasma and Erythrocyte Membranes in Dogs Fed with Commercial Granulated Food

Intake of long-chain n-3 polyunsaturated fatty acids (PUFA) benefits human and animal health. Our study aimed to analyze the long-chain n-3 PUFA content of two types of food and their effect on plasma and erythrocyte phospholipids of Belgian Shepherd dogs. A total of 10 dogs were fed commercial granulated food (Food 1), and another 10 were provided commercial Premium granulated food of high quality (Food 2). All the analyses were performed using gas-liquid chromatography. Our results showed that Food 1 contained more n-3 PUFA than Food 2, which was reflected in higher n-3 PUFA in plasma and erythrocyte phospholipids. Because long-chain n-3 PUFA in phospholipids are precursors for antioxidative molecules, further studies should investigate the effects of the analyzed commercial granulated food rich in n-3 on oxidative stress parameters in dogs.

Comparison of Fish, Krill and Flaxseed as Omega-3 Sources to Increase the Omega-3 Index in Dogs

(1) Background: it is only the longer chain omega-3 polyunsaturated fatty acids (n-3 PUFAs), eicosapentaenoic acid (20:5n-3, EPA), and docosahexaenoic acid (22:6n-3, DHA) and not the shorter chain α-linolenic acid (ALA, 18:3n-3) that have been linked to health benefits. (2) Methods: 45 dogs divided into three groups were first given premium dry food for 38 days (baseline). The O3I was then used as a diagnostic tool to provide a measure of the sum of EPA + DHA in red blood cell membranes given as a percentage of all fatty acids. The dogs were subsequently fed with either krill meal (krill), fishmeal/oil (fish) or flaxseed cake (flax) included in raw food providing daily 416 mg EPA + DHA (971 mg ALA), 513 mg EPA + DHA (1027 mg ALA) and 1465 mg ALA (122 mg EPA + DHA), respectively. (3) Results: the average baseline O3I level of all dogs was low (1.36%), warranting n-3 supplementation. After four weeks, O3I levels were significantly increased in the krill (from 1.36 ± 0.44 to 2.36 ± 0.39%) and fish (from 1.35 ± 0.22 to 1.9 ± 0.35%) groups (p < 0.001). No significant modification of the O3I was detected in the flax animals. (4) Conclusions: only marine n-3 PUFAs resulted in a significantly increased O3I, with dietary krill meal providing the highest increase.

Dietary Betaine and Fatty Acids Change Circulating Single-Carbon Metabolites and Fatty Acids in the Dog

In order to evaluate the interaction of betaine and n-3 PUFA in foods consumed by the dog, six extruded dry foods were formulated. The control food had no specific source of added betaine or n-3 fatty acids, while the test foods were supplemented with betaine, flax or fish oil in a 2 × 3 factorial design (no added n-3 source, added flax, added menhaden fish oil, and all with or without added betaine). Forty eight adult dogs were used in this study. All dogs were assigned to one of the six dietary treatments and consumed that food for the length of the 60-day study. Blood was analyzed for metabolomics (plasma), fatty acids and selected health-related analytes (serum) at the beginning and the end of the study. Added dietary betaine increased single-carbon metabolites (betaine, dimethyl glycine, methionine and N-methylalanine), decreased xenobiotics (stachydrine, N-acetyl-S-allyl-L-cysteine, 4-vinylguaiacol sulfate, pyrraline, 3-indoleglyoxylic acid, N-methylpipecolate and ectoine) and enhanced the production of eicosapentaenoic acid (EPA). Dietary betaine also decreased the concentration of circulating carnitine and a number of carnitine-containing moieties. The addition of the n-3 fatty acids alpha-linolenic, EPA and docosahexaenoic acid (DHA) increased their respective circulating concentrations as well as those of many subsequent moieties containing these fatty acids. The addition of alpha-linolenic acid increased the concentration of EPA when expressed as a ratio of EPA consumed.

Enhanced omega-3 index after long- versus short-chain omega-3 fatty acid supplementation in dogs

Background

The Omega‐3 Index is a test that measures the amount of the long‐chain omega‐3 polyunsaturated fatty acids (n‐3 PUFAs), eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) in red blood cell membranes, which is expressed as a percentage of all fatty acids. However, alpha‐linolenic acid (ALA) from flaxseed oil, which is a short‐chain n‐3 PUFA, is often promoted in pet feed as a n‐3 source, implicitly assuming it is an effective precursor of EPA and DHA.

Objective

This study was aimed to compare the effect of supplementation with a plant‐based short‐chain n‐3 PUFA source (flaxseed oil, FSO) with a marine long‐chain n‐3 PUFA source (astaxanthin krill oil, AKO) to increase the Omega‐3 Index in dogs.

Methods

Ten adult Alaskan Huskies of both genders were supplemented daily with 1,155 mg of EPA/DHA from AKO, whereas another 10 dogs received 1,068 mg ALA from flaxseed oil for 6 weeks. Fatty acid and Omega‐3 Index measurements of the two groups were taken after 0, 3 and 6 weeks for comparison.

Results

The EPA and DHA concentrations increased significantly only in the dogs fed with AKO resulting in a significant increase in mean Omega‐3 Index, from 1.68% at baseline to 2.7% after 6 weeks of supplementation (p < .0001). On the contrary, both EPA and DHA concentrations decreased significantly in the dogs fed with FSO, which led to a significant decrease in mean Omega‐3 Index from 1.6% at baseline to 0.96% at study end (p < .0001).

Conclusions

The results showed that supplementation of AKO from Antarctic krill led to a significant increase in the Omega‐3 Index in comparison to FSO in dogs. This suggests that preformed marine EPA and DHA sources are needed in dog feeds, as the dietary requirements proposed by feed industry organizations are not met with conversion from short‐chain n‐3 fatty acids.