Fermentation Characteristics of Several Carbohydrate Sources for Dog Diets Using theIn VitroGas Production Technique

Assessment of the content of macronutrients and microbiological safety of dry dog foods

In Europe, there are no legal regulations specifying maximum allowable limits for pathogenic bacteria or fungi and yeasts in dog food. For proximate composition, the European Pet Food Industry Federation (FEDIAF) nutritional guidelines provide minimum recommended levels for protein and fat only, not for other ingredients and no safe maximum levels. Therefore, the aim of this study was to evaluate the microbiological safety of 35 dry dog foods, taking into account the division into foods with grains as the main plant ingredient and those described as grain-free. We assumed that grain-included foods are more susceptible to the presence of the total number of aerobic bacteria. This parameter is an essential, hygienic criterion informing about the microbiological safety of the pet food. It also inform about the microbiological quality of the food ingredients used, the effectiveness of decontamination during the production process, sanitary and hygienic conditions during the acquisition, processing and marketing of pet food and its components. In the case of macronutrients, the results in some cases were multiples of the minimum recommended levels. The most important microorganisms that presence was found in the analyzed dog foods were indicator bacteria (E. coli and coliform bacteria, Clostridium perfringens), whose presence in feed constitutes microbiological contamination. They inform about sanitary and hygienic conditions during the production and storage of the pet food. The current guidelines recommend microbiological testing of food for the presence of Salmonella bacilli as the basic indicator for assessing the sanitary quality. No Salmonella spp. was detected in any of the foods. The remaining analyzed bacteria (Proteus spp., Enterococcus spp., Staphylococcus spp.) as well as molds and yeasts, were present in both grain-included and grain-free foods. The obtained results showed that in terms of microbiological safety, grain-included foods come out worse, because microorganisms were detected more frequently in this type of dry dog food.

Nutritional Management of Cats and Dogs with Diabetes Mellitus

This article reviews the nutritional assessment and management of diabetic dogs and cats. It discusses how to determine appropriate nutritional goals for individual patients, including comorbid patients with diabetes. Considerations for macronutrient and micronutrient modifications will be reviewed.

The effect of age and processing on the in vitro fermentation of fibrous feedstuffs by labrador retriever dogs

Dietary fibre substances in dog foods are composed of cell wall polysaccharides, non-cellulose polysaccharides, and structural non-polysaccharides. The purpose of this study was to determine the effects of dog age and heat-steam pressure (extruding process) on the in vitro fermentation of fibrous feedstuffs (sugar beet pulp, tomato pomace, wheat bran, corn bran, and rice bran) to be included in dog foods. The fibrous feedstuffs were incubated with a fermentation medium mixture and faeces inoculum, which were collected from two 6 month old (puppy), two 2 year old (adult), and two 8 year old (geriatric) dogs. The in vitro cumulative gas production (at 6, 12, 18, 24, 36, and 48 h), true-organic matter disappearance (T-OMd) (at 6, 12, 24, and 48 h), and molarities of short chain fatty acids (SCFA) (acetic, propionic, and butyric acids; AA, PA, and BA) in fermentation fluid (at 24 h) of fibrous feedstuffs were determined. The extruding process increased the in vitro cumulative gas production of rice bran (at 12, 18, 24, and 48 h) and wheat bran (at 6, 12, 24, and 36 h) (P < 0.05). In addition, in vitro cumulative gas production values of tomato pomace (at 12, 18, 24, 36, and 48 h) were reduced by the extruding process (P < 0.05). The extruding process increased the in vitro T-OMd values of sugar beet pulp (at 6, 12, and 24 h), wheat and rice bran (at 6 and 12 h), and the molarities of AA, BA, and total SCFA of the in vitro fermentation fluid of sugar beet pulp and wheat bran (P < 0.05). The in vitro cumulative gas production values of tomato pomace from faecal inoculums of the puppy and adult dogs were higher than that of the geriatric dog (P < 0.05). The in vitro T-OMd of sugar beet pulp (at 48 h) and extruded corn bran (at 6 h) with faecal inoculums of adult dog was higher than those of inoculum from puppy faeces (P < 0.05). The molarity of AA of tomato pomace with adult dog's faecal inoculum was higher than those from puppy and geriatric dog (P < 0.05). The molarities of AA, BA, and total SCFA with corn bran from faeces inoculums of the puppy and adult dog was higher than that of the geriatric dog (P < 0.05). The molarities of AA and total SCFA of the in vitro fermentation fluid of extruded rice bran with faecal inoculums from the geriatric dogs was higher than those with faecal inoculums from the puppy and adult dogs (P < 0.05). As a result, the extruding process positively affected the in vitro fermentation values of sugar beet pulp, wheat bran, and rice bran. Furthermore, the organic acid molarities of the in vitro fermentation fluid of extruded rice bran from the geriatric dog was higher than those from the puppy and adult dogs. Sugar beet pulp, tomato pomace, wheat bran, and corn bran can be used as a source of fibre in food for puppy, adult, and geriatric large dogs.

Amaranthus grain as a new ingredient in diets for dairy cows: productive, qualitative, and in vitro fermentation traits

BACKGROUND

In recent decades, grain amaranths have attracted attention due to their valuable combination of nutritional traits, with higher protein and oil content than conventional cereals. Before they can be proposed as an unconventional ingredient in animal feed, many aspects still need to be investigated from field production to nutritive value. The present research aimed to study the agronomic traits, proximate composition, and digestibility/degradability, fatty acid profile, antioxidant activity, and total phenolic content of two grain amaranth species, Amaranthus cruentus and Amaranthus hypochondriacus (for a total of six accessions), grown in a Mediterranean environment.

RESULTS

Both species showed seed yields comparable to or higher than the traditional cereal crops in the same environment. On the whole, A. cruentus resulted in a higher seed production than A. hypochondriacus. Mexico and Montana accessions, both belonging to A. cruentus, showed the highest yield (3.73 t ha^-1 , on average). Few differences emerged in nutritive value between species and accessions: the Illinois accession of A. cruentus showed the best performance in terms of in vitro degradability and gas production, but not for volatile fatty acid production; the fermentation kinetics was slowest in the Illinois accession and fastest in the Montana accession of A. cruentus and the India accession of A. hypochondriacus.

CONCLUSION

From a health perspective, the Nebraska accession of A. hypochondriacus represents the best accession, with the lowest saturated fatty acid content and the highest polyunsaturated fatty acid content. © 2022 The Authors. Journal of The Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Evaluation of the Effect of Different Dietary Lipid Sources on Dogs’ Faecal Microbial Population and Activities

Simple Summary

Saturated fatty acids might be a valuable source of energy to guarantee all physiological functions in companion animals. Polyunsaturated fatty acids are essential in several metabolic processes and structural body functions. In this regard, hemp oil can be used as a rich source of polyunsaturated fatty acids in animal diets. In this study, hemp seed oil and swine tallow were added to a commercial canned diet. These high-lipid-content diets (hemp diet: 55.1 g/100 kcal ME; tallow diet: 65.1 g/1000 kcal ME) were compared with one rich in starch. Following the recruitment of 12 dogs, three experimental groups were set up. At 30 days of diet administration, faeces samples were collected from each group to perform an in vitro trial and faecal bacteria count. In the first evaluation, the faecal inoculum obtained from dogs fed a diet supplemented with hemp showed higher fermentation activity and lower gas production at 24 h of incubation. The bacterial count demonstrated an increase in Lactobacillus when hemp group faeces were tested. Both in vivo and in vitro acetic acid production increased. The results obtained suggest an influence of the fatty acid profile on the microbial population.

Abstract

Lipids represent a significant energy source in dogs’ diets. Moreover, dogs need some essential fatty acids, such as linoleic and α-linolenic fatty acids, because they are not able to produce them endogenously. This study aimed to evaluate the effect of different dietary lipid sources on faecal microbial populations and activities using different evaluations. Hemp seed oil and swine tallow were tested as lipid supplements in a commercial canned diet at a ratio of 3.5% (HL1 and HL2, respectively). These diets were compared with one rich in starch (HS). Twelve dogs were recruited and equally divided into three groups. Faeces samples at 30 days were used as inoculum and incubated with three different substrates (MOS, inulin, and cellulose) using the in vitro gas production technique. The faecal cell numbers of relevant bacteria and secondary metabolites were analysed (in vivo trial). In vitro evaluation showed that the faeces of the group fed the diet with hemp supplementation had better fermentability despite lower gas production. The in vivo faecal bacterial count showed an increase in Lactobacillus spp. In the HL1 group. Moreover, a higher level of acetate was observed in both evaluations (in vitro and in vivo). These results seem to indicate a significant effect of the dietary fatty acid profile on the faecal microbial population.

Altered Intestinal Production of Volatile Fatty Acids in Dogs Triggered by Lactulose and Psyllium Treatment

The intestinal microbiome of dogs can be influenced by a number of factors such as non-starch polysaccharides as well as some non-digestible oligo- and disaccharides. These molecules are only decomposed by intestinal anaerobic microbial fermentation, resulting in the formation of volatile fatty acids (VFAs), which play a central role in maintaining the balance of the intestinal flora and affecting the health status of the host organism. In the present study, the effects of lactulose and psyllium husk (Plantago ovata) were investigated regarding their influence on concentrations of various VFAs produced by the canine intestinal microbiome. Thirty dogs were kept on a standard diet for 15 days, during which time half of the animals received oral lactulose once a day, while the other group was given a psyllium-supplemented diet (in 0.67 and in 0.2 g/kg body weight concentrations, respectively). On days 0, 5, 10 and 15 of the experiment, feces were sampled from the rectum, and the concentration of each VFA was determined by GC-MS (gas chromatography−mass spectrometry). Lactulose administration caused a significant increase in the total VFA concentration of the feces on days 10 and 15 of the experiment (p = 0.035 and p < 0.001, respectively); however, in the case of psyllium supplementation, the concentration of VFAs showed a significant elevation only on day 15 (p = 0.003). Concentrations of acetate and propionate increased significantly on days 5, 10 and 15 after lactulose treatment (p = 0.044, p = 0.048 and p < 0.001, respectively). Following psyllium administration, intestinal acetate, propionate and n-butyrate production were stimulated on day 15, as indicated by the fecal VFA levels (p = 0.002, p = 0.035 and p = 0.02, respectively). It can be concluded that both lactulose and psyllium are suitable for enhancing the synthesis of VFAs in the intestines of dogs. Increased acetate and propionate concentrations were observed following the administration of both supplements; however, elevated n-butyrate production was found only after psyllium treatment, suggesting that the applied prebiotics may exert slightly different effects in the hindgut of dogs. These findings can be also of great importance regarding the treatment and management of patients suffering from intestinal disorders as well as hepatic encephalopathy due to portosystemic shunt.

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.

Fermentability of select polyphenol-rich substrates in the canine faecal inoculum and their interaction with a canine-origin probiotic: an in vitro appraisal

BACKGROUND

This in vitro study aimed to compare the hindgut fermentability and digestibility of four different sources of polyphenols, namely orange (Citrus sinensis) peel (ORP), pomegranate (Punica granatum) peel (PMP), Indian blackberry (Syzygium cumini) pulp (IBP), and Jerusalem artichoke (Helianthus tuberosus) tuber (JAT), and their influence on the viability of a canine-origin probiotic, Lactobacillus johnsonii CPN23.

RESULTS

An in vitro gas production test carried out using the four substrates for a period of 72 h with dog faecal inoculum indicated that the total gas production, dry matter, and organic matter digestibility were significantly (P < 0.001) higher with JAT, whereas they were lowest for PMP. Short-chain fatty acids production was significantly higher (P < 0.001) with ORP and JAT, with the least values recorded for PMP. The ammonia-nitrogen production was significantly (P < 0.001) higher with JAT than with ORP, IBP, and PMP, and a lower (P < 0.001) pH was evident with ORP, JAT, and IBP than with PMP. Viability of L. johnsonii CPN23 was tested in the presence of the polyphenol-rich extract from each of the four sources at varying doses (50, 500, 1000, 2500, and 5000 μg mL^-1 ). PMP extract showed the highest inhibitory effect on the probiotic bacteria's growth in a dose- and time-dependent manner (P < 0.001). ORP and IBP extracts were stimulatory at the optimum dosage, whereas JAT reduced probiotic activity significantly at all doses tested.

CONCLUSION

Overall, the results indicate a higher hindgut fermentability of JAT, ORP, and IBP, suggesting their potential beneficial effects for gut health application. An interaction study between polyphenol extract and L. johnsonii CPN23 showed a stimulatory effect of polyphenolic extracts from ORP and IBP on probiotic growth at optimal dosage. Consistent with the fermentation study findings, PMP extract reduced the growth of L. johnsonii CPN23 irrespective of the doses tested. © 2021 Society of Chemical Industry.

Orange fibre effects on nutrient digestibility, fermentation products in faeces and digesta mean retention time in dogs

Fermentable fibres are used in commercial dog food to promote intestinal health by providing substrates for better metabolic activity of the gut microbiota. Brazil is the world's largest producer of oranges, from which it is possible to obtain fibre with a relevant soluble fraction. The present study compared the effects of two inclusions of orange fibre (1% and 3%, on as fed basis) with a negative control (without addition of fibre source) and two positive controls, beet pulp (3%) and purified inulin (1%), totalling five extruded diets for dogs. The experiment followed a randomised block design with 4 blocks of 10 dogs, 2 dogs per food in each block, totalling 8 dogs per diet. The apparent total tract nutrient digestibility was determined by total faecal collection. Faecal pH and fermentation product content were also measured. The digesta mean retention time (DMRT) was evaluated using plastic markers. The inclusion of a 3% fibre source in diets with 3% orange fibre and beet pulp reduced DM, OM, and energy digestibility (p < 0.05). Diets with 3% orange fibre, beet pulp and 1% inulin presented lower crude protein digestibility than the control (p < 0.05). Dietary fibre digestibility was higher for orange fibre-supplemented diets than inulin (p < 0.05). Beet pulp and 3% orange fibre inclusions resulted in increased moisture content in the faeces of dogs (p < 0.05) but did not alter DMRT. Total short-chain fatty acids were higher than the control in the faeces of dogs fed both orange fibre levels and the beet pulp-supplemented diet (p < 0.05), and the inulin diet-fed dogs presented intermediate values. Butyrate was higher in the faeces of dogs fed the diets supplemented with 1% and 3% orange fibre (p < 0.05), and similar values to the control were observed for beet pulp- and inulin-fed animals. Thus, it was concluded that orange fibre presented higher apparent total tract dietary fibre digestibility than beet pulp and had a fermentation profile in the colon that promoted the generation of butyrate, an effect not observed for inulin and beet pulp.

Clinical Findings in Healthy Dogs Fed With Diets Characterized by Different Carbohydrates Sources

In recent years, pet owners have become more interested in the ingredients, and quality of pet-food, and several studies have demonstrated that feed management could affect healthy status. Recently, some authors indicated that commercial diets formulated without cereals, or using unconventional protein, and starch sources, can cause a reduction in taurine levels in both whole blood, and plasma. Nevertheless, the specific mechanism by means of which nutritional factors determine this reduction is not completely clear. Thirty neutered half-breed dogs were recruited at a kennel in the province of Naples (Italy) to investigate the influence of carbohydrates sources, and dietary density of nutrients on healthy status of dogs in terms of blood count, and biochemical parameters. The dogs were housed in the kennel and divided into three distinct groups. Three iso-energy, and iso-nitrogen commercial kibble diets (named GF1, GF2, and CB) with different protein, and carbohydrates contents, and carbohydrates sources were chosen for the trial. The chemical composition and amino acid profile of each of the three tested diets were analyzed. Moreover, blood samples of each dog were collected to evaluate the hematological and biochemical profiles. The taurine level was determined both on plasma and whole blood. The effect of the diets was analyzed statistically, and all tested diets were compared to the control one. There were significant differences between the three tested diets as regards their chemical composition. The concentrations of all amino acids seem to reflect protein content diets. The hematological profile resulted within the ranges considered physiological for the canine species for all subjects. Compared to the control diet, the three tested diets showed significant differences in blood count for MCHC and platelets. The biochemical profile showed significant differences between the diets, particularly their AST, fructosamine, lipase, and triglycerides values. The diets did not affect the blood and plasma taurine levels. They resulted in higher than optimal reserve levels. Preliminary results showed that the sources of carbohydrates and use of balanced diets affected only some biochemical parameters and did not alter the levels of taurine in healthy adult dogs.

Dried yeast cell walls high in beta-glucan and mannan-oligosaccharides positively affect microbial composition and activity in the canine gastrointestinal tract in vitro

The outer cell wall of yeast is characterized by high levels of β-glucans and mannan-oligosaccharides (MOS), which have been linked with beneficial effects on intestinal health and immune status in dogs. In this study, a standardized in vitro simulation of the canine gastrointestinal tract (Simulator of the Canine Intestinal Microbial Ecosystem; SCIME) was used to evaluate the effect of a Saccharomyces cerevisiae-based product, consisting of 27.5% β-glucans and 22.5% MOS, on the activity (as assessed by measurement of fermentative metabolites) and composition (as assessed by 16S-targeted Illumina sequencing) of canine intestinal microbiota. The S. cerevisiae-based product was tested at three different dosages, i.e., 0.5, 1.0, and 2.0 g/d. A dose-dependent fermentation pattern was observed along the entire length of the colon, as shown by the increased production of the health-related acetate, propionate, and butyrate for the three concentrations tested (0.5, 1.0, and 2.0 g/d). A consistent finding for all three tested concentrations was the increased propionate production (P < 0.05) in the simulated proximal and distal colon. These changes in terms of fermentative metabolites could be linked to specific microbial alterations at the family level, such as the specific stimulation of the propionate-producing families Porphyromonadaceae and Prevotellaceae upon in vitro exposure to the S. cerevisiae-based product. Other consistent changes in community composition upon repeated exposure included the decrease in the Enterobacteriaceae and the Fusobacteriaceae families, which both contain several potentially opportunistic pathogens. Altogether, the generated data support a possible health-promoting role of a product high in β-glucans and MOS when supplemented to the dogs' diet.

Effects of the solubility of yeast cell wall preparations on their potential prebiotic properties in dogs

Derivatives of yeast cell wall (YCW) have been studied for their potential prebiotic effects. Recently, new purified and soluble preparations have been developed in an attempt to increase their biological actions. Two YCW preparations, one conventional and another with higher solubility of the mannan oligosaccharide fraction, were evaluated on dogs. One food formulation was used, divided into the following treatments: CON-control, without yeast cell wall addition; YCW-addition of 0.3% of a conventional yeas cell wall extract; YCWs-addition of 0.3% of a yeast cell wall extract with high mannan oligosaccharide solubility. Twenty-four beagle dogs were used, eight per food, distributed on a block design. Blocks lasted 32 days, and TNF-a, IL-6, IL-10, ex vivo production of hydrogen peroxide and nitric oxide by peripheral neutrophils and monocytes, phagocytic index, and fecal IgA were evaluated at the beginning and end of each period. Additionally, nutrient digestibility, feces production and quality, and fermentation products were quantified. The results were evaluated by analysis of variance and compared using the Tukey test (P<0.05), using the basal immunological parameters as a covariate. The inclusion of YCWs reduced fat digestibility (P<0.05), increased the concentration of butyrate and putrescine, and reduced lactate in feces (P<0.05), showing that mannan oligosaccharide solubilization resulted in higher fermentation of this compound and altered the metabolism of the gut microbiota. Lower IL-6 on serum was verified for dogs fed the YCWs diet (P<0.05), suggesting a reduction in the inflammatory activity of dogs. Higher phagocytic index was verified for peripheral monocytes after the intake of the YCW food, suggesting better innate immunity. In conclusion, the solubilization of the mannooligosaccharide fraction alters its interaction with gut microbiota and biological actions in animals, although both yeast cell wall preparations exhibited prebiotic effects on dogs.

Beet pulp intake and hairball faecal excretion in mixed-breed shorthaired cats

Hairball formation may induce vomiting and intestinal obstruction in predisposed cats. Some insoluble fibres as sugarcane fibre and cellulose can prevent hairball formation. The aim of this study was to evaluate the effect of beet pulp consumption, a moderate soluble and fermentable fibre source, on faecal trichobezoars excretion in adult shorthaired cats fed kibble diets. Eighteen mixed-breed shorthaired cats and three extruded diets were used as follows: a basal diet without added fibre source (PB0-8.8% dietary fibre); BP8-8% inclusion of beet pulp (17.5% of dietary fibre); BP16-16% inclusion of beet pulp (23.8% of dietary fibre). The cats were fed during 31 days and faeces quantitatively collected during three periods of 3 days each (from days 3-5; 15-17; 26-28). Gastrointestinal transit time was determined in the last 3 days of study (from days 29-31). The trichobezoars were separated from faeces, collected, dried and washed in ether for complete removal of all faecal material. The results were submitted to repeated-measure analysis of variance and means evaluated by polynomial contrast (p < 0.05). Beet pulp increased faecal production (p < 0.001) and reduced gastrointestinal transit time (p = 0.003). No alterations were found on trichobezoar faecal excretion, both as considered in number per cat per day of mg per cat per day (p > 0.05). Beet pulp intake did not reduce the number or the size of hairballs eliminated via faeces of shorthaired cats.

The effect of age and carbohydrate and protein sources on digestibility, fecal microbiota, fermentation products, fecal IgA, and immunological blood parameters in dogs

The present study compared the effects of diets formulated with fibers of different fermentability and protein sources of animal or vegetable origins on old and adult dogs. The experiment was organized in a 3 (diets) × 2 (ages) factorial arrangement, totaling 6 treatments. Thirty-six Beagle dogs were used (18 old dogs [10.2 ± 1.0 yr] and 18 young adult dogs [2.6 ± 0.9 yr]), with 6 dogs per treatment. Three diets with similar compositions were used: a nonfermentable insoluble fiber source (sugarcane fiber) and chicken byproduct meal (nonfermentable fiber [NFF] diet), a fermentable fiber source (beet pulp) and chicken byproduct meal (fermentable fiber [FF] diet), and soybean meal as a protein and fiber source (soybean meal [SM] diet). Data were evaluated using the MIXED procedure and considering the effects and interactions of block, animal, diets, and age. Means were compared using Tukey's test ( < 0.05). Age × diet interactions were evaluated when < 0.1. Old dogs had a reduced coefficient of total tract apparent digestibility of DM, which was explained by the age and diet interaction of CP and fat digestibility that was lower for old than for adult dogs fed the FF diet ( < 0.05). The SM diet obtained higher DM, OM, CP, and fiber digestibility compared with the NFF diet ( < 0.05). The feces of dogs fed the NFF diet had increased DM content ( < 0.05). The short-chain fatty acids (SCFA) did not change by age group and were higher for dogs fed the FF and SM diets compared with dogs fed the NFF diet ( < 0.05). An age and diet interaction was observed for lactate and was increased in the feces of old dogs compared with adult dogs fed the FF diet ( < 0.05). Fecal putrescine, cadaverine, and spermine were increased for old dogs compared with adult dogs ( < 0.05), and the spermidine fecal concentration was increased for dogs fed the SM diet regardless of age ( < 0.05). Old dogs had reduced peripheral T and B lymphocytes ( < 0.05). An age and diet interaction was observed for fecal IgA ( < 0.001). Adult dogs fed the SM diet had increased IgA in feces compared with animals fed the NFF and FF diets ( < 0.05). However, for old dogs, both the FF and SM diets induced increased IgA compared with the NFF diet ( < 0.05). In conclusion, beet pulp may reduce digestibility and induce increased lactate in the feces of old dogs. The protein and oligosaccharides of soybean meal are digestible by dogs, induce the production of SCFA and spermidine, and increase fecal IgA. Old dogs had increased putrecine, cadaverine, and spermine fecal concentrations.

In vitro digestion and fermentation characteristics of canola co-products simulate their digestion in the pig intestine

Canola co-products are sources of amino acid and energy in pig feeds, but their fermentation characteristics in the pig intestine are unknown. Thus, we determined the in vitro fermentation characteristics of the canola co-products Brassica juncea solvent-extracted canola meal (JSECM), Brassica napus solvent-extracted canola meal (NSECM), B. napus expeller-pressed canola meal (NEPCM) and B. napus cold-pressed canola cake (NCPCC) in comparison with soybean meal (SBM). Samples were hydrolysed in two steps using pepsin and pancreatin. Subsequently, residues were incubated in a buffer solution with fresh pig faeces as inocula for 72 h to measure gas production. Concentration of volatile fatty acids (VFA) per gram of dry matter (DM) of feedstuff was measured in fermented solutions. Apparent ileal digestibility (AID) and apparent hindgut fermentation (AHF) of gross energy (GE) for feedstuffs were obtained from pigs fed the same feedstuffs. On DM basis, SBM, JSECM, NSECM, NEPCM and NCPCC contained 15, 19, 22, 117 and 231 g/kg ether extract; and 85, 223, 306, 208 and 176 g/kg NDF, respectively. In vitro digestibility of DM (IVDDM) of SBM (82.3%) was greater (P<0.05) than that of JSECM (68.5%), NSECM (63.4%), NEPCM (67.5%) or NCPCC (69.8%). The JSECM had greater (P<0.05) IVDDM than NSECM. The IVDDM for NSECM was lower (P<0.05) than that for NEPCM, which was lower (P<0.05) than that for NCPCC. Similarly, AID of GE was greatest for SBM followed by NCPCC, JSECM, NEPCM and then NSECM. Total VFA production for SBM (0.73 mmol/g) was lower (P<0.05) than that of JSECM (1.38 mmol/g) or NSECM (1.05 mmol/g), but not different from that of NEPCM (0.80 mmol/g) and NCPCC (0.62 mmol/g). Total VFA production of JSECM was greater (P<0.05) than that of NSECM. Total VFA production of NSECM was greater (P<0.05) than that of NEPCM or NCPCC, which differed (P<0.05). The ranking of feedstuffs for total VFA production was similar to AHF of GE. In conclusion, in vitro fermentation characteristics of canola co-products and SBM simulated their fermentation in the small and large intestine of pigs, respectively. The 30% greater VFA production for JSECM than NSECM due to lower lignified fibre of JSECM indicates that fermentation characteristics differ between canola species. The NSECM had the highest fermentability followed by NEPCM and then NCPCC, indicating that fat in canola co-products can limit their fermentability in the hindgut.

Prediction of digestible energy and gross energy digestibility of feeds and diets in ostriches

1. The aim of this study was to assess regression equations able to predict the digestible energy (DE) and gross energy digestibility (GEd) of feed ingredients and diets for ostriches. 2. Results of chemical-nutritional characteristics from 17 ingredients (two varieties of maize, two barleys, oat, triticale, wheat bran, soybean meal, sunflower meal, beet pulp, maize silage, alfalfa hay, 4 alfalfa meals and lupin) and 12 experimental diets were used in a stepwise procedure. 3. Acid detergent lignin (ADL) was the first independent variable included in the model to predict the DE of all the samples (R(2) = 0.65 and Residual Standard Deviation (RSD) 1.02). When the concentration of ash, acid detergent fibre (ADF) and crude fibre were included in the model, the R(2) value of the regression equation increased (from 0.65 to 0.85) and RSD decreased (from 1.02 to 0.48). 4. The ADL concentration was also the first independent variable chosen by the stepwise regression analysis for the estimation of GEd from chemical-nutritional characteristics of feeds, explaining 57% of the total GEd variation. The concentrations of crude protein and ADF included at the second and third steps in the model increased the R(2) (up to 0.70 and 0.73, respectively) and decreased the RSD values (from 0.29 to 0.21 and 0.20, respectively). When other variables as crude fibre, ash and gross energy were included in the model, the coefficient of determination and the RSD strongly improved (0.85 and 0.12, respectively).