Comparative nutrient digestibility in dogs, blue foxes, mink and rats

Comparing the standardized amino acid digestibility of an alternative protein source with commercially available protein-based ingredients using the precision-fed cecectomized rooster assay

Using single-cell-based proteins in pet foods is of interest, but little testing has been done. Therefore, our objective was to determine the amino acid (AA) digestibilities, assess protein quality of a novel microbial protein (MP) (FeedKind), and compare it with other protein-based ingredients using the precision-fed cecectomized rooster assay. Test ingredients included: MP, chicken meal (CM), corn gluten meal (CGM), pea protein (PP), and black soldier fly larvae. Thirty cecectomized roosters (n = 6/ingredient) were randomly assigned to test ingredients. After 24 h of feed withdrawal, roosters were tube-fed 15 g test ingredient and 15 g corn, and then excreta were collected for 48 h. Endogenous AA corrections were made using additional roosters. Digestible indispensable AA score (DIAAS)-like values were calculated to determine protein quality according to Association of American Feed Control Officials (AAFCO), The European Pet Food Industry Federation, and National Research Council reference values for growing and adult dogs and cats. Data were analyzed using the Mixed Models procedure of SAS 9.4, with P ≤ 0.05 being significant. All reactive lysine:total lysine ratios, an indicator of heat damage, were higher than 0.9, except for CM (0.86). Digestibility of indispensable and dispensable AA were >85% and >80% for MP, respectively, with indispensable AA digestibilities being >80% for all other ingredients. In general, CGM had the highest, while CM had the lowest AA digestibilities. Two exceptions were lysine and tryptophan. Lysine digestibility for MP was higher than that of all other ingredients, while tryptophan digestibility for MP was higher than that of CM, CGM, and PP. Threonine digestibility was highest for CGM and MP. Valine digestibility was highest for CGM, PP, and MP. DIAAS-like calculations identified limiting AA of each ingredient and depended on the reference used and life stage and species of animal. Using AAFCO guidelines, all DIAAS-like values for MP were >100 suggesting that it could be used as the sole source of protein in adult dog and cat diets; only methionine had DIAAS-like values <100 for growing kittens. For dogs, limiting AA was most commonly methionine, threonine, and tryptophan in the other protein sources. For cats, limiting AA was most commonly lysine and methionine. Lysine was severely limited in CGM across all life stages considered. Further research in dogs and cats is necessary, but our data suggest that the MP tested has high AA digestibilities and is a high-quality protein source that may be useful in pet foods.

Influence of Bile Salts and Pancreatin on Dog Food during Static In Vitro Simulation to Mimic In Vivo Digestion

The addition of pancreatin and bile salts in different concentrations during in vitro digestion causes changes in the digestibility of crude protein (CP), fat, and dry matter (DM). The effects of bile salts and pancreatin on the digestibility of ether extract (EE), CP, and DM in developing a static in vitro digestion model for dogs were assessed using different concentrations of pancreatin (0, 1, 2.5, 5, and 10 g/L digestive solution) and bile salts (0, 2.5, 6.25, 12.5, and 25 g/L digestive solution). The data were analyzed using one-way analysis of variance. Digestibility of EE increased with the addition of bile salts (p < 0.05), whereas that of CP decreased with ≤0.25 g (1.0 g/L digestive solution) pancreatin. The digestibility of DM decreased significantly in all groups supplemented with ≥3.125 g (12.5 g/L digestive solution) bile salts and 0.25−2.5 g (1−10 g/L digestive solution) pancreatin and was the lowest with 6.25 g (25 g/L digestive solution) of bile salts (p < 0.05). These findings could facilitate the development of effective static in vitro digestion models for dogs.

Effects of Thai native chicken breast meat consumption on serum uric acid level, biochemical parameters, and antioxidant activities in rats

This study aimed to evaluate the effect of a high protein diet comprising breast meat from commercial broiler (BR), Thai native (PD), and commercial broiler × Thai native crossbred (KKU-ONE) chicken on serum uric acid, biochemical parameters, and antioxidant activities in rats. Male Sprague–Dawley rats were divided into four groups. The control group received a standard chow diet, and the other three groups were fed a high protein diet (70% standard diet + 30% BR, PD, or KKU-ONE chicken breast) for five weeks. The PD- and KKU-ONE-fed rats had lower plasma total cholesterol and triglyceride levels than the control rats. A decrease in HDL-c was also observed in rats fed a diet containing BR. Liver weight, liver enzyme, plasma ALP, xanthine oxidase activity, serum uric acid, creatinine, superoxide production, and plasma malondialdehyde levels increased in BR-fed rats. The findings of this study might provide evidence to support the use of Thai native and Thai native crossbred chicken breast meat as functional foods.

Dietary supplementation with fiber, "biotics," and spray-dried plasma affects apparent total tract macronutrient digestibility and the fecal characteristics, fecal microbiota, and immune function of adult dogs

A variety of functional ingredients, including fibers, prebiotics, probiotics, and postbiotics may be added to pet foods to support gastrointestinal and immune health. While many of these ingredients have been tested individually, commercial foods often include blends that also require testing. This study was conducted to evaluate the effects of diets containing blends of fibers, "biotics," and/or spray-dried plasma on apparent total tract digestibility (ATTD), stool quality, fecal microbiota and metabolites, and immune health outcomes of adult dogs. A total of 12 healthy adult intact English pointer dogs (6 M, 6 F; age = 6.4 ± 2.0 yr; BW = 25.8 ± 2.6 kg) were used in a replicated 3 × 3 Latin square design to test diets formulated to: 1) contain a low concentration of fermentative substances (control diet, CT); 2) be enriched with a fiber-prebiotic-probiotic blend (FPPB); and 3) be enriched with a fiber-prebiotic-probiotic blend + immune-modulating ingredients (iFFPB). In each 28-d period, 22 d of diet adaptation was followed by a 5-d fecal collection phase and 1 d for blood sample collection. All data were analyzed using SAS 9.4, with significance being P < 0.05 and trends being P < 0.10. FPPB and iFPPB diets led to shifts in numerous outcome measures. Dry matter (DM), organic matter, fat, fiber, and energy ATTD were lower (P < 0.01), fecal scores were lower (P < 0.01; firmer stools), and fecal DM% was higher (P < 0.0001) in dogs fed FPPB or iFPPB than those fed CT. Serum triglycerides and cholesterol were lower (P < 0.01) in dogs fed FPPB or iFPPB than those fed CT. Fecal protein catabolites (isobutyrate, isovalerate, indole, and ammonia) and butyrate were lower (P < 0.05), while fecal immunoglobulin A (IgA) was higher (P < 0.01) in dogs fed FPPB and iFPPB than those fed CT. Fecal microbiota populations were affected by diet, with alpha-diversity being lower (P < 0.05) in dogs fed iFPPB and the relative abundance of 20 bacterial genera being altered in dogs fed FPPB or iFPPB compared with CT. The circulating helper T cell:cytotoxic T cell ratio was higher (P < 0.05) in dogs fed iFPPB than those fed CT. Circulating B cells were lower (P < 0.05) in dogs fed FPPB than those fed iFPPB, and lower (P < 0.05) in dogs fed iFPPB than those fed CT. Our results demonstrate that feeding a fiber-prebiotic-probiotic blend may provide many benefits to canine health, including improved stool quality, beneficial shifts to fecal microbiota and metabolite profiles, reduced blood lipids, and increased fecal IgA.

Short-term effect of oral amoxicillin treatment on the gut microbial community composition in farm mink (Neovison vison)

It is well documented that antibiotics have pronounced modulatory effects on the intestinal bacterial community of both humans and animals, with potential health consequences. The gut microbiota of mink has however attracted little attention due to low bacterial load and fast gastrointestinal transit time, questioning its relevance. In this study, we hypothesise that oral amoxicillin treatment affects the gut microbiota in mink. This was investigated in a controlled trial including 24 animals of which 12 were treated with amoxicillin for 7 days. By applying 16S rRNA gene sequencing, we found that the faecal microbiota was markedly altered already after 2 days of treatment, with a surprising increase in diversity to resemble the feed. The diversity within the mucosa at termination was however reduced, which indicates this compartment as an important colonisation site in mink. No impact on blood biochemistry, lipid metabolism, serum amyloid A, vitamins A and E and histomorphology of the gut and liver was found; however, a slight decrease in fat digestibility was observed. We suggest that early-life use of amoxicillin in mink production may be counteractive as dysbiosis of the microbiota during infancy is increasingly being recognised as a risk factor for future health.

Digestibility Is Similar between Commercial Diets That Provide Ingredients with Different Perceived Glycemic Responses and the Inaccuracy of Using the Modified Atwater Calculation to Calculate Metabolizable Energy

Dietary starch is required for a dry, extruded kibble; the most common diet type for domesticated felines in North America. However, the amount and source of dietary starch may affect digestibility and metabolism of other macronutrients. The objectives of this study were to evaluate the effects of 3 commercial cat diets on in vivo and in vitro energy and macronutrient digestibility, and to analyze the accuracy of the modified Atwater equation. Dietary treatments differed in their perceived glycemic response (PGR) based on ingredient composition and carbohydrate content (34.1, 29.5, and 23.6% nitrogen-free extract for High, Medium, and LowPGR, respectively). A replicated 3 × 3 Latin square design was used, with 3 diets and 3 periods. In vivo apparent protein, fat, and organic matter digestibility differed among diets, while apparent dry matter digestibility did not. Cats were able to efficiently digest and absorb macronutrients from all diets. Furthermore, the modified Atwater equation underestimated measured metabolizable energy by approximately 12%. Thus, the modified Atwater equation does not accurately determine the metabolizable energy of high quality feline diets. Further research should focus on understanding carbohydrate metabolism in cats, and establishing an equation that accurately predicts the metabolizable energy of feline diets.

Effect of soaking, fermentation with lactobacillus and enzyme treatment on nitrogen-corrected apparent metabolizable energy values of wheat in cockerels and quails

An experiment was carried out to determine nitrogen-corrected apparent metabolizable energy (AMEn) values of processed wheat products with two levels of enzyme (0 and 0.5 g/kg) and five processing methods [control (C), water-soaking for 12 h (SO12h), 24 h (SO24h) and 48 h (SO48h) and fermentation with lactobacillus (FL)] in two species of poultry (cockerel and Japanese quail). In this study, each processing method group had six replications with two cockerels or four quails per replication. The results showed that the calculated AMEn values of processed wheat by different methods were as follows: C-12.61 and 12.60; SO12h-12.75 and 12.73; SO24h-12.80 and 12.79; SO48h-12.97 and 12.96; and FL-13.36 and 13.33 MJ/kg for cockerels and quails, respectively, indicating that fermentation improved AMEn values compared with the others. The mean AMEn of processed wheat with enzyme (13.12 MJ/kg) was significantly higher than that of processed wheat without enzyme (12.64 MJ/kg). However, there were no significant differences in the AMEn of processed wheat between cockerels and quails. The interaction between species and levels of enzyme in AMEn values was not significant. There was no significant difference (p > 0.05) in three-way interactions among species, levels of enzyme and wheat processing methods for AMEn values. In conclusion, the results of the experiment suggest that the FL was more effective processing method of wheat to obtain high level of AMEn values than the others, and the combination of enzyme and processing methods can increase the AMEn values compared with processing methods alone.

Copper bioavailability, blood parameters, and nutrient balance in mink

A 3 × 3 + 1 factorial experiment was conducted based on a completely randomized design to evaluate the effects of different sources of copper on plasma metabolites, nutrient digestibility, relative copper bioavailability, and retention of some minerals in male mink. Animals in the control group were fed a basal diet, which mainly consisted of corn, fish meal, meat and bone meal, and soybean oil, with no copper supplementation. Mink in the other 9 treatments were fed the basal diet supplemented with Cu from reagent-grade copper sulfate (CuSO4), tribasic copper chloride (TBCC), or copper methionine (CuMet). Copper concentrations of the experimental diets were 50, 100, and 150 mg Cu/kg DM. Blood samples were collected via the toe clip at the end of study (d 42) to determine blood hematology and blood metabolites. A metabolism trial of 4 d was conducted during the last week of experimental feeding. There was a linear (P < 0.01) effect of dose of Cu on plasma Cu concentrations, ceruloplasmin concentration, and Cu-Zn superoxide dismutase activity. A linear response to Cu dose was noted for fat (P < 0.05) digestibility. Supplemental dose of Cu linearly increased (P < 0.05) liver Cu and decreased (P < 0.05) liver Zn level but did not alter liver Fe. The concentration of liver Cu of the mink fed with TBCC and CuMet diets was greater (P < 0.05) than that fed CuSO4. Compared with CuSO4 (100%), relative bioavailability values of TBCC were 104 and 104%, based on serum ceruloplasmin and liver copper, respectively, and relative bioavailability values of CuMet were 130 and 111%. CuMet and TBCC are more bioavailable than CuSO4. In conclusion, the relative bioavailability of CuMet obtained in this study was greater than that of CuSO4 and TBCC. Dose of Cu had an important effect on the regulating ceruloplasmin concentration, Cu-Zn superoxide dismutase activity, and the digestion of dietary fat in mink.

Nutrient digestibility and colonic fermentation processes in species of the families Mustelidae and Canidae fed the same diet

Nutrient digestibility was compared and the influence of colonic fermentation processes on nutrient digestibility was determined in the American mink (Neovison vison) and the silver fox (Vulpes vulpes). It was hypothesized that gut microbiota exert varied effects on digestion processes in the analyzed species. The experiment was performed in December, on a group of 10 male mink and 10 male foxes. All animals were fed identical diets for fur-bearing carnivores, with the following chemical composition (%): dry matter (DM)-33.12, total protein (TP)-12.01, ether extract (EE)-8.64, crude fiber (CF)-12.01, N-free extracts (N-FE)-9.32, and gross energy (GE)-7.313 MJ/kg(-1) . The coefficients of DM, OM, TP and EE digestibility were significantly higher in foxes than in mink. Mink were characterized by significantly higher utilization of N-FE. In foxes, as compared with mink, fermentation rates were higher in the final section of the gastrointestinal tract, which improved nutrient digestibility. In mink, characterized by lower fermentation rates in the colon, increased enzyme secretion by bacterial cells is one of the physiological mechanisms that enable to optimize nutrient absorption in the large intestine.

Effects of dietary copper on elemental balance, plasma minerals and serum biochemical parameters of growing-furring male mink (Mustela vison)

The objectives of this study were to study the effects of different levels of dietary copper on copper and zinc balance, plasma minerals and serum biochemical parameters of mink in the growing-furring periods. One hundred and five standard dark male mink were randomly assigned to seven groups with the following dietary treatments: basal diet with no supplemental Cu (Control); basal diet supplemented with either 6, 12, 24, 48, 96, or 192 mg/kg Cu from copper sulfate, respectively. The average daily gain (ADG) linearly (P = 0.0026, P = 0.0006) responded to increasing levels of Cu; maximal growth was seen in the Cu24 group. Feed efficiency tended to improve with the increase of dietary copper level (linear P = 0.0010, quad, P = 0.0011). Fecal copper, urinary copper, retention copper responded in a linear (P < 0.05) fashion with increasing level of Cu. The effect of level of Cu was linear (P < 0.001) for plasma Cu concentration. The serum glutamic-oxalacetic transaminase (GOT) and glutamic-pyruvic transaminase (GPT) activities were increased linearly (P < 0.05) with dose of Cu, but serum total protein (TP) and albumin (ALB) concentrations decreased linearly (P < 0.05) as dietary copper levels increased. Effect of level of Cu was linear (P < 0.001) for serum ceruloplasmin (CER) concentration or Cu-Zn superoxide dismutase (Cu-Zn SOD) activity. Supplemental dose of Cu linearly decreased serum triglyceride (TG) (P = 0.011) and total cholesterol (TC) (P = 0.007). Our results indicated that the activity of Cu-dependent enzymes was enhanced by increasing dietary Cu concentration and that supplementation of Cu in the diet of mink could alter the plasma lipid profile and copper concentration.

Evaluation of eight commercial dog diets

Estimation of the quality of commercial diets is a topic of interest for the majority of dog owners. Recently, in a French consumer association magazine, an evaluation of eight dog commercial dry diets (from super-premium, basic-nutrition, private-label and economy brands) according to several nutritional criteria was published. The aims of the study were: (1) to evaluate the apparent digestibility of these diets; (2) to score these diets according to digestibility results; and (3) to compare these data with the scoring of the magazine. Six adult Beagle dogs were enrolled for the digestibility trials. Diets were scored according to energy, crude protein and crude fat (CF) apparent digestibility coefficients, digestible protein-to-energy ratios and ash content. Each of the five criteria was scored from 4 to 20 points. The ranges of crude protein, CF, crude fibre and ash content were 20·9-30·6 %, 6·8-19·7 %, 2·2-3·3 % and 4·6-9·7 % on a DM basis, respectively. The ranges of energy, crude protein and CF apparent digestibility coefficients were 72·6-87·7 %, 70·4-82·5 % and 76·1-95·4 %, respectively. The range of the protein-to-energy ratio was 10-14 digestible crude protein per MJ metabolisable energy. Little overlap in the scoring systems was found, but the private-label brand and economy brand diets presented the lowest scores in the two systems. These results showed that the evaluation of commercial diets should take into account multiple nutritional aspects. In particular, analytical and biological (digestibility) criteria should be considered as complementary in the evaluation of dry dog commercial diets.

Effects of different sources and levels of copper on growth performance, nutrient digestibility, and elemental balance in young female mink (Mustela vison)

An experiment was conducted in a 3 × 3 + 1 factorial experiment based on a completely randomized design to evaluate the effects of different sources of copper on growth performance, nutrient digestibility and elemental balance in young female mink on a corn-fishmeal-based diet. Animals in the control group were fed a basal diet (containing 8.05 mg Cu/kg DM; control), which mainly consisted of corn, fish meal, meat bone meal, and soybean oil, with no copper supplementation. Minks in other nine treatments were fed basal diets supplemented with Cu from reagent-grade copper sulfate, tribasic copper chloride (TBCC) and copper methionate. Cu concentrations of experiment diets were 10, 25, and 40 mg/kg copper. A metabolism trial of 4 days was conducted during the last week of experimental feeding. Final body weight and average daily gain increased (linear and quadratic, P < 0.05) as Cu increased in the diet; maximal growth was seen in the Cu25 group. Cu supplementation slightly improved the feed conversion rate (P = 0.095). Apparent fat digestibility was increased by copper level (P = 0.020). Retention nitrogen was increased by copper level (linear, P = 0.003). Copper source had a significant effect on copper retention with Cu-Met and copper sulfate treatments retention more than TBCC treatments (P < 0.05). Our results indicate that mink can efficiently utilize added dietary fat and that Cu plays an important role in the digestion of dietary fat in mink, and mink can efficiently utilize Cu-Met and CuSO4.

Effects of dietary copper on nutrient digestibility, tissular copper deposition and fur quality of growing-furring mink (Mustela vison)

The present study investigated the effects of dietary copper (Cu) on growth performance and fur quality in growing-furring minks. One hundred and five standard dark female minks were randomly assigned to seven groups with the following dietary treatments: basal diet with no supplemental Cu (control) and basal diet supplemented with either 6, 12, 24, 48, 96 or 192 mg/kg Cu from copper sulphate, respectively. Our data showed that final body weight (P = 0.033), daily gain (P = 0.029) and fat digestibility (P = 0.0006) responded to increasing levels of Cu. The activity of glutamic-oxalacetic transaminase (GOT) and glutamic-pyruvic transaminase (GPT) in serum increased (linear and quadratic, P < 0.05) as Cu increased in the diet. Increasing Cu improved total protein (TP) and albumin (ALB) (quadratic, P < 0.05). The level of ceruloplasmin (CER) responded in a linear (P < 0.0001) and quadratic (P < 0.0001) form with increasing level of Cu. Colour intensity of those minks pelted suggested that relatively high levels of supplemental Cu have a beneficial effect on intensifying hair colour of dark mink but did not affect leather thickness. Liver Cu and plasma Cu concentrations of the mink linearly (P < 0.0001) responded to increasing levels of Cu. Our results indicate that growing-furring mink can efficiently utilize added dietary fat and that Cu plays an important role in the digestion of dietary fat in growing-furring mink, and supplemental dietary Cu in growing-furring mink promotes fat digestion and improve hair colour.

Digestibility of two diet items by captive eastern quolls (Dasyurus viverrinus)

The eastern quoll (Dasyurus viverrinus) is a carnivorous Australian marsupial that has undergone significant geographical range contraction since European settlement, and is extinct on the mainland. Nutrition is not well researched in captive eastern quolls, and captive diets often consist of commercial pet foods as opposed to raw meat or insect diets. Improving nutrition will enhance reproductive output and ensure suitable numbers of quolls are bred to be used in translocation programs. The present study analyzed the composition of kangaroo mince and chicken necks, and the digestibility of these items, in a captive environment. The quolls had high apparent total tract digestibility on the chicken neck and kangaroo mince treatments (DM 83-88%, GE 95-97%, protein 94-97%, and lipids 94-95%, respectively). The apparent total tract digestibility of DM, GE, and proteins was significantly higher (t14= 2.465, P < 0.05; t14= 2.489, P < 0.05; t14= 5.470, P < 0.01, respectively) on the kangaroo mince treatment compared with the chicken neck treatment. This study provides the first data on Cu (-18-37%), S (86-95%), and Zn (26-28%) apparent total tract digestibility in a Dasyurid. Data gathered during this study can be used to improve management practices for captive quolls, including diet formulation and mineral supplementation.

Food transit time, nutrient digestibility and nitrogen retention in farmed and feral American mink (Neovison vison)--a comparative analysis

The aim of this study was to determine whether farming leads to changes in gastrointestinal function and nitrogen metabolism in farmed mink (FA), as compared with their wild-living counterparts. Three digestibility and balance trials were carried out. Experiment I was performed in May, and experiments II and III were conducted in September 2011. Farmed mink with the standard coat colour were purchased from a production farm in south-eastern Poland. Feral mink were harvested using cages in the hunting grounds of the Polish Hunting Association, Branch in Olsztyn. The experimental materials comprised of the following: trial I - adult males (eight animals per group), trial II - young females (six animals per group), trial III-young animals (five males and five females per group). Food transit time was measured during digestibility trials, on 10 consecutive days. The coefficients of nutrient and energy digestibility and daily nitrogen balance values were compared between groups in each experiment. It was found that farming contributed to changes in gastrointestinal function and nitrogen metabolism in mink. Farmed animals were characterized by a longer bowel transit time, a tendency towards higher nutrient digestibility and higher nitrogen retention, which resulted from selection for higher productivity.

Nutrient digestibility in Arctic fox (Vulpes lagopus) fed diets containing animal meals

Three digestibility experiments on Arctic foxes were carried out. Control groups were fed standard diets (C1 and C2) composed of fresh or frozen animal by-products and steamed ground grain. Dry experimental diets (E1 and E2) contained animal meals, extracted meals and fat, were mixed with water prior to administration. In a preliminary experiment, the digestibility of dry diet E1 moistened with water for 15min and 24h was compared to determine the optimum moistening time during the experimental period proper. The preliminary experiment showed that moistening time had no significant effect on digestibility. In the main experiment, two independent digestibility trials were performed to compare the digestibility of diets fed to foxes during growth (C1 vs. E1) and fur development (C2 vs. E2). Better nutrient digestibility was noted for control diets, compared to experimental. The greatest differences were reported for total protein digestibility. Protein contained in meals undergoes denaturation during heat treatment, which reduces digestibility. It was found that the retention of nitrogen in relation to nitrogen digestion was higher in foxes fed experimental diets (E1 and E2).

Surviving on cached foods — the energetics of egg-caching by arctic foxes

Food-caching by arctic foxes ( Vulpes lagopus (L., 1758)) is a behavioural adaptation thought to increase winter survival, especially in bird colonies where a large number of eggs can be cached during a short nesting season. In this paper, we measured the energy content of greater snow goose ( Chen caerulescens atlantica Kennard, 1927) eggs and evaluated their perishability when cached in tundra soil for a whole summer. We estimated that eggs lost only ~8% of their dry mass over 60 days of storage in the ground. We used published estimates on digestibility of nutrients by arctic foxes to estimate that fresh and stored goose eggs contained 816 and 730 kJ of metabolizable energy, respectively, a difference of 11%. Using information on arctic fox energetics, we evaluated that 145 stored eggs were required to sustain the growth of one pup from the age of 1 to 3 months (nutritional independence). Moreover, 23 stored eggs were energetically equivalent to the average fat deposit of an arctic fox during winter. Finally, we calculated that an adult arctic fox would need to recover 160–220 stored eggs to survive 6 months in resting conditions during cold winter temperatures. This value increased to 480 when considering activity cost. Based on egg acquisition and caching rates observed in many goose colonies, we conclude that cached eggs represent an important source of energy relative to the needs of an arctic fox during winter, and have thus a high fitness value.

Effects of lactic acid fermentation and gamma irradiation of barley on antinutrient contents and nutrient digestibility in mink (Mustela vison) with and without dietary enzyme supplement

The experiment was conducted to study the effects of fermentation of barley, using two different strains of lactic acid bacteria, a Lactobacillus plantarum/pentosus strain isolated from spontaneously fermented rye sourdough (AD2) and a starch-degrading Lactobacillus plantarum (AM4), on contents of mixed-linked (1 --> 3) (1 --> 4)-beta-glucans, alpha-amylase inhibitor activity, inositol phosphates, and apparent digestibility of macronutrients in mink. Effects of fermentation were compared with effects of gamma irradiation (gamma-irradiation: 60Co gamma-rays at 25 kGy). The diets were fed to mink with and without a supplementary enzyme preparation. Both lactic acid fermentation and gamma-irradiation followed by soaking and incubation, reduced concentrations of soluble beta-glucans, phytate and alpha-amylase inhibitor activity. Dietary enzyme supplementation increased significantly digestibility of crude protein, fat, starch and crude carbohydrate (CHO). Fermentation of the barley increased digestibility of starch and CHO. Fermentation with lactic acid bacteria AD2 resulted in higher starch and CHO digestibility than strain AM4, and had greater effect than gamma-irradiation, soaking and incubation. The highest digestibility of starch and CHO was obtained after AD2 fermentation followed by enzyme supplementation. It is concluded that both lactic acid fermentation of barley and enzyme supplementation have positive nutritional implications in the mink by limiting the effects of antinutrients and improving digestibility and energy utilization.

Comparative apparent total tract digestibility of major nutrients and amino acids in dogs (Canis familiaris), blue foxes (Alopex lagopus) and mink (Mustela vison)

Major nutrient and amino acid digestibilities were evaluated in experiments with dogs (Canis familiaris), blue foxes (Alopex lagopus) and mink (Mustela vison) using seven extruded diets containing different protein sources. Four dogs (German shepherd), four blue foxes and four mink were offered each of the experimental diets to determine apparent total tract digestibility. Average digestibility of crude protein (CP) in blue foxes and mink was similar, and lower than the corresponding value in dogs (0·834 and 0·831 v. 0·864) (P< 0·001). CP digestibility in blue foxes showed significant correlations with dogs and mink (P< 0·05), while no significant correlation was observed between dogs and mink. Average digestibility of most amino acids was significantly lower in blue foxes than in dogs (P< 0·001), whereas mink digested most essential amino acids at the same level as did dogs. Most non-essential amino acids were digested at a significantly lower rate in the mink than in the dog and the blue fox (P< 0·001). There were significant correlations in the digestibility of most amino acids between dogs and blue foxes, and between blue foxes and mink (P< 0·05). Correlations were significant between dogs and mink for the digestibility of most essential amino acids (P< 0·05) but not significant (P> 0·05) for several non-essential amino acids. Average digestibility of crude fat was high and similar among the species studied: 0·968, 0·967 and 0·959 in dogs, blue foxes and mink, respectively. Average digestibility of starch ranged from 0·971 in mink to 0·998 in dogs; significantly higher in dogs than in blue foxes and mink, and significantly higher in blue foxes than in mink (P< 0·001). It was concluded that digestibility determined with mink, blue foxes or dogs may be used to predict digestibilities in the other investigated species. However, both the characteristics of the protein sources as well as the individual amino acid studied will influence the difference in digestibility among the species.

Ileal and total tract nutrient digestibility in blue foxes (Alopex lagopus) fed extruded diets containing different protein sources

This study compared apparent ileal and total tract digestibility of macronutrients and amino acids in blue foxes (Alopex lagopus) fed dry extruded diets. The control diet contained fish meal as the main protein source, while in the other diets 50% of the fish meal protein was replaced by not de-hulled solvent-extracted soybean meal, meat meal or bacterial protein meal. Ileal digestibility was obtained with animals modified with ileorectal anastomosis (IRA method). There were no significant differences in the average digestibility of CP, Lys, Trp, Val, Ala or Glu between IRA modified and intact animals. Average ileal digestibilities of His, Thr, Asp, Cys, Gly, Hyp, Pro, Ser, starch and total carbohydrates (CHO) were significantly lower compared with total tract values. Average ileal digestibility of Arg, Ile, Leu, Met, Phe, Tyr and crude fat was significantly higher than total tract digestibility. Digestibility measured in IRA modified animals showed less variability compared with values from intact animals. There were significant differences among diets in ileal as well as total tract digestibility of orude protein, most amino acids, starch and CHO, and in ileal digestibility of crude fat. Ileal crude protein digestibility of the diets ranged from 81.0-86.4% and total tract digestibility from 82.5-86.4%. Ileal amino acid digestibilities ranged from 70.1 (Asp) to 93.3% (Arg) and total tract values ranged from 72.8 (Cys) to 92.2% (Arg). Both ileal and total tract digestibilities of crude protein and most amino acids were significantly lower for diets containing meat meal or bacterial protein meal compared with the control fish meal-based diet and the diet with soybean meal. Although ileal digestibility may be more accurate than total tract digestibility in estimating the protein and amino acid supply in blue foxes, total tract digestibility may be acceptable because of numerically small differences between ileal and total tract digestibilities for protein and most amino acids. It was further concluded that ileal digestibilities of starch and CHO in the blue fox are lower than corresponding total tract digestibilities.

Comparative nutrient digestibility of arctic foxes (Alopex lagopus) on Svalbard and farm-raised blue foxes (Alopex lagopus)

Arctic foxes from Svalbard (n=4) and farmed blue foxes (n=4) was used in a digestibility experiment with a high-carbohydrate feed to add more information to the nutritional physiology of the arctic fox, and to compare its digestive capacity with that of the farmed blue fox. The arctic fox has a diet containing mainly protein and fat from mammals and birds, while farmed blue foxes have been exposed to an omnivorous dietary regime for more than 80 generations. The experiment showed in general no difference in digestive capacity for protein and fat between the foxes (P>0.05), but for carbohydrates, including starch and glucose, the blue fox revealed higher digestibility values. The superior digestive capacity for carbohydrates in blue fox might be a result of a long-term selection of animals digesting dietary carbohydrates more efficiently, or that an early age exposition to dietary carbohydrates has given permanent improvement of the carbohydrate digestion in the gut.