RESUMO
Different analytical (enzyme system and near-infrared spectroscopy (NIRS)) and statistical (single and multiple regressions) approaches were used to predict in vivo standardized pre-caecal digestibility (PCD) of crude protein (CP) and amino acids (AA) in cereal grains for growing pigs as well as in vitro nitrogen (N) solubility. Furthermore, different chemical and physical characteristics were categorized (e.g. crude nutrients, AA, minerals, fibre components or combinations of these) and used for generating prediction equations. There were strong linear relationships (p < .05) between in vivo PCD of CP and essential AA and in vitro N solubility when grain species was considered as covariate in the model. Predicting in vivo PCD values using various chemical and physical characteristics produced inconsistent results among different grain species and AA and could therefore not be used for predicting PCD. It is possible to predict in vitro N solubility from chemical and physical characteristics for some grain species. However, the relationships between some of these categories and the in vitro N solubility were not consistent and not always causative or physiologically explainable. The R2 of NIRS for predicting in vitro N solubility was at a relatively high level (up to R2 = 0.80). This level of R2 indicates that a classification of the grain samples in, for example, high, medium and low in vitro N solubility levels is possible, but it does not allow for a quantitative prediction of the in vitro N solubility. In conclusion, the present database can be used for establishing a ranking of different cereal grain species for PCD of CP and essential AA values. However, it was not possible to create clear prediction equations for in vivo or in vitro digestibility values. Therefore, greater variation within grain species, for example due to different growing and harvesting conditions, is warranted for predicting PCD values of individual grain samples.
Assuntos
Ração Animal/análise , Dieta/veterinária , Digestão/fisiologia , Grão Comestível/química , Nitrogênio/metabolismo , Suínos/crescimento & desenvolvimento , Animais , Grão Comestível/metabolismo , Geno Valgo , Nitrogênio/química , Espectrofotometria Infravermelho/métodosRESUMO
The present study assessed effects of diets containing varying calcium-phosphorus (CaP) concentration and fermentable substrates on digestibility of diets, intestinal microbiota and immune system using 32 crossbred pigs (initial BW 54.7 kg). In a 2 × 2 factorial arrangement, pigs were fed either a corn-soybean meal (CSB) or corn-field pea (CFP) diet with either low [-] (4.4 g Ca/kg; 4.2 g total P/kg) or high [+] (8.3 g Ca/kg; 7.5 g total P/kg; supplemented with monocalcium phosphate) CaP content for a period of 9 weeks. In week 8, blood samples were taken, and at the end of the trial, all pigs were euthanized to collect digesta and mesenteric lymphoid tissue. Apparent total tract digestibility (ATTD) of P was greater (p < 0.05) for pigs fed the CaP+ and CFP diets than CaP- and CSB diets. The myo-inositol 1,2,3,4,5,6-hexakis (dihydrogen phosphate) (InsP6 ) concentration in jejunal digesta was higher (p < 0.05) for CaP+ than in CaP- fed pigs. In addition, caecal and faecal InsP5 isomer concentration were greater (p < 0.05) for CSB than CFP diets. In the caecum, gene copy numbers of saccharolytic bacteria, such as Eubacterium rectale and Roseburia spp., as well as SCFA concentration were higher (p < 0.05) for CaP+ than CaP- diets. In particular, innate immune cell numbers, such as natural killer cells, dendritic cells, monocytes and neutrophils, were greater (p < 0.05) for CaP+ than CaP- fed pigs. Diets high in CaP resulted in higher abundance of potential beneficial bacteria and might promote the first line of defence enhancing the activation of the cellular adaptive immune response, thereby possibly decreasing the risk for intestinal disturbances. These results strongly suggest that both, CaP supply and dietary ingredients differing in fermentability, may beneficially affect gut health through increase in SCFA-producing bacteria and/or bacteria with anti-inflammatory properties.
Assuntos
Cálcio da Dieta/administração & dosagem , Microbioma Gastrointestinal/efeitos dos fármacos , Intestinos/microbiologia , Fósforo/administração & dosagem , Ácido Fítico/metabolismo , Suínos/crescimento & desenvolvimento , Ração Animal/análise , Animais , Bactérias/metabolismo , Cálcio da Dieta/farmacologia , Dieta/veterinária , Digestão , Ácidos Graxos Voláteis/metabolismo , Fermentação , Fósforo/farmacologia , RNA Bacteriano/genética , RNA Ribossômico 16S/genéticaRESUMO
BACKGROUND: Diet influences the porcine intestinal microbial ecosystem. Barrows were fitted with ileal T-cannulas to compare short-term effects of eight different wheat or barley genotypes and period-to-period effects on seven bacterial groups in ileal digesta and faeces by qPCR. RESULTS: Within genotypes of wheat and barley, there was no difference (P > 0.05) in contents of analysed NSP, yet cereal types differed (P < 0.001) except for soluble arabinoxylans. Genotypes showed no effect on bacterial gene copy numbers. In ileal digesta of barley- compared to wheat-fed pigs, log10 copy numbers were lower (P < 0.05) for total eubacteria (9.6-9.8), Bacteroides-Prevotella-Porphyromonas (6.5-6.8), Clostridium cluster IV (6.7-6.9), and Roseburia spp. (6.6-7.2), while higher copy numbers were found for Lactobacillus spp. (9.4-8.8). Enterobacteriaceae (7.0-7.8) and Bifidobacterium spp. (7.0-7.7) were lower (P < 0.001) in faeces of barley compared to wheat-fed pigs. Ileal eubacteria, Clostridium cluster IV and Roseburia spp. linearly increased from period 1 to 8 for both cereals (P < 0.05). CONCLUSION: Wheat and barley differently influence microbial composition particularly in the small intestine, with barley increasing the Lactobacillus spp.:Enterobacteriaceae ratio, underlining its potential to beneficially manipulate the intestinal microbial ecosystem.
Assuntos
Bactérias/metabolismo , Hordeum/genética , Suínos/fisiologia , Triticum/genética , Ração Animal/análise , Animais , Bactérias/genética , Dieta/veterinária , Fezes/microbiologia , Conteúdo Gastrointestinal , Genótipo , Íleo/microbiologia , MasculinoRESUMO
Genotypes of cereal grains, including winter barley (n = 21), maize (n = 27), oats (n = 14), winter rye (n = 22), winter triticale (n = 21) and winter wheat (n = 29), were assayed for their chemical composition and physical characteristics as part of the collaborative research project referred to as GrainUp. Genotypes of one grain species were grown on the same site, except maize. In general, concentrations of proximate nutrients were not largely different from feed tables. The coefficient of variation (CV) for the ether extract concentration of maize was high because the data pool comprised speciality maize bred for its high oil content. A subset of 8 barley, 20 rye, 20 triticale and 20 wheat samples was analysed to differ significantly in several carbohydrate fractions. Gross energy concentration of cereal grains could be predicted from proximate nutrient concentration with good accuracy. The mean lysine concentration of protein was the highest in oats (4.2 g/16 g N) and the lowest in wheat (2.7 g/16 g N). Significant differences were also detected in the concentrations of macro elements as well as iron, manganese, zinc and copper. Concentrations of arsenic, cadmium and lead were below the limit of detection. The concentration of lower inositol phosphates was low, but some inositol pentaphosphates were detected in all grains. In barley, relatively high inositol tetraphosphate concentration also was found. Intrinsic phytase activity was the highest in rye, followed by triticale, wheat, barley and maize, and it was not detectable in oats. Substantial differences were seen in the thousand seed weight, test weight, falling number and extract viscoelasticity characteristics. The study is a comprehensive overview of the composition of different cereal grain genotypes when grown on the same location. The relevance of the variation in composition for digestibility in different animal species will be subject of other communications.
Assuntos
Carboidratos/química , Grão Comestível/química , Grão Comestível/genética , Regulação da Expressão Gênica de Plantas/fisiologia , Genótipo , Proteínas de Plantas/química , 6-Fitase/química , 6-Fitase/metabolismo , Metabolismo dos Carboidratos , Fosfatos de Inositol/química , Fosfatos de Inositol/metabolismo , Minerais/química , Minerais/metabolismo , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , SementesRESUMO
Dietary composition is a major factor influencing the intestinal microbial ecosystem of pigs. To alleviate weaning-associated disorders, variations in dietary protein supply may beneficially affect microbial composition in the gastrointestinal tract of piglets. A total of 48 piglets, fitted with simple ileal T-cannulas, was used to examine the effect of protein supply of either highly digestible casein or less digestible, fiber-rich soybean meal (SBM) on the composition of the intestinal microbiota. Gene copies of 7 bacteria groups were determined by real-time PCR in ileal digesta and feces. Ileal counts of total eubacteria, the Bacteroides-Prevotella-Porphyromonas group, Enterobacteriaceae and Clostridium Cluster XIVa were higher (P < 0.001) in the casein-based diets. Fecal counts of all analyzed bacterial groups were higher for the SBM-based diets (P < 0.001), apart from Enterobacteriaceae (P < 0.05) which were higher in the casein-based diets. Ileal counts of lactobacilli linearly increased as the crude protein level was increased up to 335 g/kg (P < 0.01). The Bacteroides-Prevotella-Porphyromonas group linearly decreased in ileal samples (P < 0.01) and increased in fecal samples (P < 0.05) as the crude protein level in the SBM-based diet was increased. Both, protein level and protein source may affect intestinal microbial balance. Higher dietary protein levels in combination with diets low in fiber contents might stimulate proliferation of protein fermenting bacteria in piglet's large intestine. Further studies are warranted to clarify, whether this would be associated with intestinal disturbances.
Assuntos
Biota , Caseínas/metabolismo , Dieta/métodos , Proteínas Alimentares/metabolismo , Fezes/microbiologia , Glycine max/metabolismo , Íleo/microbiologia , Ração Animal , Animais , Animais Recém-Nascidos , Bactérias/classificação , Bactérias/genética , Carga Bacteriana , Reação em Cadeia da Polimerase em Tempo Real , SuínosRESUMO
BACKGROUND: There is evidence that dietary betaine might improve nutrient digestibilities in pigs due to its osmoprotective properties. This in vitro study was performed to assess the potential of supplemented betaine sources to affect fermentation characteristics of different carbohydrate and protein combinations, under conditions of osmotic stress. In vitro fermentation was performed by use of the modified Hohenheim gas test with pig faeces as microbial inoculum. RESULTS: At the end of in vitro fermentation under osmotic stress conditions, differences (P < 0.05) in gas production, ammonia concentration, and concentration of short-chain fatty acids were observed for the different carbohydrates, while for the two proteins only differences (P < 0.05) in ammonia and short-chain fatty acid concentration were obtained. Supplementation of a native betaine source rather than addition of pure betaine increased propionic acid (P < 0.05) and butyric acid (P < 0.05) production. CONCLUSION: These results suggest that only supplementation of a native betaine source but not of pure betaine products affects microbial fermentation under osmotic stress. Furthermore, both the carbohydrate and protein source play an important role in modifying microbial activity under osmotic stress conditions. It can also be concluded that the modified Hohenheim gas test is suitable to scrutinise fermentation activity of different assay substrates under osmotic stress.
Assuntos
Betaína/farmacologia , Carboidratos da Dieta/metabolismo , Proteínas Alimentares/metabolismo , Suplementos Nutricionais , Fármacos Gastrointestinais/farmacologia , Osmose , Estresse Fisiológico , Amônia/metabolismo , Animais , Ácido Butírico/metabolismo , Dieta/veterinária , Ácidos Graxos Voláteis/metabolismo , Fermentação , Gases/metabolismo , Masculino , Propionatos/metabolismo , SuínosRESUMO
BACKGROUND: The study was conducted to determine the effect of graded levels of feed intake on apparent (AID) and standardized (SID) ileal digestibilities of crude protein (CP) and amino acids (AA) in diets for piglets. The piglets were surgically fitted with simple T-cannulas at the distal ileum. The cornstarch-casein-soybean meal-based diets were fed at three graded levels of feed intake corresponding to 30, 45 and 60 g kg(-1) body weight (BW) per day. RESULTS: The AID and SID of most AA were quadratically affected by the feed intake level (P≤0.05). Initially, both AID and SID of most AA increased up to 1.9 percentage units as the feed intake level was increased from 30 to 45 g kg(-1) BW. Thereafter, these AID and SID values decreased by 2.6 and 2.7 percentage units, respectively, as the feed intake level was further increased from 45 to 60 g kg(-1) BW. CONCLUSION: Because the voluntary feed intake is highly variable in piglets after weaning, comparison of ileal AA digestibilities between and within studies may be confounded by variations in feed intake level. Thus, when designing digestibility studies with piglets, a standardization of feed intake should be taken into consideration.
Assuntos
Aminoácidos/metabolismo , Dieta , Proteínas Alimentares/metabolismo , Digestão , Ingestão de Energia , Íleo/metabolismo , Ração Animal , Animais , Caseínas , Padrões de Referência , Projetos de Pesquisa , Glycine max , Sus scrofa , Zea maysRESUMO
In order to further increase the stability of the cannula behind the ribs and to facilitate cannula exteriorization in growing pigs, the present study aimed to evaluate whether elongation of the cannula flange could increase the stability of the cannula behind the ribs and to develop a tool to improve the exteriorization of the cannula through the ribs. Moreover, it was assessed whether a special skin protection paste and soft polyurethane foam material used in daily skin care could prevent erythema around the fistula. The feasibility of both, the modified simple T-cannula and daily skin care procedure, was evaluated in a digestibility experiment. Simple T-cannulae were made of high-molecular-weight polyethylene and inserted into the distal ileum of eight growing pigs (average body weight at surgery 30 kg). Modifications in the cannula design included a longer flange (11 cm) that was narrowed from the center to the ends and a bending of the flange to adapt it to the curve of the costal arch. In order to reduce the damage to the thread on the outer cannula barrel during surgery, a special surgical plug in conjunction with a screw thread on the inside of the barrel was developed. With respect to the daily cleaning of the fistula, a special skin protection paste was applied on the skin around the fistula to create a waterproof film that entirely sealed the skin. Additionally, foam material was inserted between the retaining ring and the skin to absorb the leaking digesta. Monitoring of the pigs throughout the trial showed that modifications in cannula design proved to be useful as they facilitated exteriorization of the cannula through the ribs and stability of the cannula behind the ribs. Moreover, the use of the skin protection paste and foam material during postsurgical treatment of growing pigs effectively prevented skin irritation around the flank area.
Assuntos
Cânula/veterinária , Cateterismo/veterinária , Íleo/cirurgia , Higiene da Pele/veterinária , Suínos/cirurgia , Ração Animal , Animais , Peso Corporal , Cateterismo/métodos , Digestão/fisiologiaRESUMO
Standardised ileal digestibilities (SID) of crude protein and amino acids (AA) originating from 24 different feed ingredients, including 11 feed ingredients produced from soybeans, seven by-products of starch processing, four whey products and two fish meals, were determined in piglets by means of the difference method. For the indispensable AA, the highest SID values were obtained in three out of four whey proteins (SID ≥90% for most indispensable AA), one out of two fish meals (SID ≥86%), soy protein concentrate, hydrolysed soy protein isolate (SID ≥86% for most indispensable AA), and by-products of starch processing (SID ≥84% for most indispensable AA). The lowest SID values were obtained in extruded soybeans and microbially fermented soy protein (SID ≤78% for most indispensable AA), whereas the SID values for high-protein soybean meal were intermediate (SID 80-89% for indispensable AA except for Thr). The SID values in the three enzymatically fermented soy proteins (SID 80-94% for most indispensable AA) were similar to those in high-protein soybean meal and soy protein concentrate. The results of the present study indicate that SID values of AA in feed ingredients for piglets differ considerably from those reported for grower-finisher pigs, thus there may be a need for separate feed tables for piglets.
Assuntos
Aminoácidos/metabolismo , Ração Animal/análise , Dieta/veterinária , Proteínas Alimentares/metabolismo , Digestão , Sus scrofa/fisiologia , Animais , Suplementos Nutricionais/análise , Produtos Pesqueiros/análise , Íleo/fisiologia , Masculino , Distribuição Aleatória , Glycine max/química , Amido/química , Proteínas do Soro do Leite/análiseRESUMO
A study was carried out to investigate whether blends of betaine, organic acids and inulin may improve their efficacy to modulate intestinal bacterial populations in weaned pigs compared with the single application of these additives. Moreover, potential postprandial diurnal variations in ileal bacterial numbers were determined in piglets fed the control diet. Twenty-four piglets in two consecutive experiments received a wheat-barley-soybean meal control diet (Con) or the Con diet supplemented with betaine (BET; 0.2%), an organic acid blend (AC; 0.4%) or inulin (IN; 0.2%) as single additives or in combination. Ileal bacterial numbers of total bacteria, lactobacilli, bifidobacteria (p < 0.05) and enterobacteria (p < 0.10) showed a postprandial diurnal variation, thus spot sampling of ileal digesta for the determination of bacterial numbers may not be representative. There were only small effects of BET, AC and IN on ileal and faecal bacterial populations. BET + AC increased total ileal bacterial numbers compared to the Con and AC treatments. BET reduced lactobacilli numbers in faeces, whereas BET + IN increased ileal numbers of bifidobacteria compared to AC and IN. There is evidence that BET, AC, IN and their combinations may affect proliferation of beneficial bacterial populations, although this has to be confirmed in further studies.
Assuntos
Ácidos/farmacologia , Betaína/farmacologia , Microbioma Gastrointestinal/efeitos dos fármacos , Inulina/farmacologia , Sus scrofa/metabolismo , Sus scrofa/microbiologia , Ração Animal/análise , Animais , Betaína/administração & dosagem , Dieta/veterinária , Suplementos Nutricionais/análise , Fezes/microbiologia , Íleo/efeitos dos fármacos , Íleo/microbiologia , Inulina/administração & dosagem , Masculino , Compostos Orgânicos/administração & dosagem , Compostos Orgânicos/farmacologia , Distribuição AleatóriaRESUMO
BACKGROUND: Basal ileal endogenous amino acid (AA) losses (IAAend) and standardized ileal digestibility (SID) values of cereal grains, such as barley, are apparently underestimated when determined according to the nitrogen (N)-free method. Regression analysis between the dietary apparent ileal digestible content (cAID) and total crude protein (CP) and AA can be considered as alternative approach to obtain more accurate values for IAAend and SID of AA in cereal grains. METHODS: Eight hulled barley genotypes were used, with barley being the only source of CP and AA in the assay diets. The diets contained 95 % as-fed of these eight barley genotypes each, ranging in CP content between 109.1 and 123.8 g/kg dry matter (DM). Nine ileally T-cannulated barrows, average body weight (BW) 30 ± 2 kg, were allotted to a row-column design comprising eight periods with 6 d each and nine pigs. On d 5 and the night of d 6 of every period, ileal digesta were collected for a total of 12 h. The IAAend and the SID were determined by linear regression analysis between cAID and total dietary CP and AA. RESULTS: There exist linear relationships between cAID and total CP and AA (P < 0.001). The IAAend of CP, Lys, Met, Thr and Trp amounted to 35.34, 1.08, 0.25, 1.02 and 0.38 g/kg DM intake (DMI), respectively, which are greater compared to average IAAend determined previously under N-free feeding conditions. The SID of CP, Lys, Met, Thr and Trp was 90, 79, 85, 79 and 86 %, respectively, and was greater when compared to tabulated values. Moreover, these SID values were greater than those reported in literature, based on correction of apparent ileal digestibility (AID) of CP and AA for their IAAend values. Summarized, the results of the present regression analysis indicate greater IAAend in barley-based diets compared to those obtained by N-free feeding. CONCLUSIONS: For low-protein feed ingredients like barley the regression method may be preferred over correction of AID values for their IAAend determined under N-free feeding conditions, as intercepts and slopes of the linear regression equations between cAID and total dietary CP and AA provide direct estimates of IAAend and SID of CP and AA in the presence of the assay feed ingredient.
RESUMO
The intestinal microbiota and its metabolites appear to be an important factor for gastrointestinal function and health. However, research is still needed to further elaborate potential relationships between nutrition, gut microbiota and host's health by means of a suitable animal model. The present study examined the effect of two different diets on microbial composition and activity by using the pig as a model for humans. Eight pigs were equally allotted to two treatments, either fed a low-fat/high-fiber (LF), or a high-fat/low-fiber (HF) diet for 7 weeks. Feces were sampled at day 7 of every experimental week. Diet effects on fecal microbiota were assessed using quantitative real-time PCR, DNA fingerprinting and metaproteomics. Furthermore, fecal short-chain fatty acid (SCFA) profiles and ammonia concentrations were determined. Gene copy numbers of lactobacilli, bifidobacteria (P<0.001) and Faecalibacterium prausnitzii (P<0.05) were higher in the LF pigs, while Enterobacteriaceae were more abundant in the HF pigs (P<0.001). Higher numbers of proteins affiliated to Enterobacteriaceae were also present in the HF samples. Proteins for polysaccharide breakdown did almost exclusively originate from Prevotellaceae. Total and individual fecal SCFA concentrations were higher for pigs of the LF treatment (P<0.05), whereas fecal ammonia concentrations did not differ between treatments (P>0.05). Results provide evidence that beginning from the start of the experiment, the LF diet stimulated beneficial bacteria and SCFA production, especially butyrate (P<0.05), while the HF diet fostered those bacterial groups which have been associated with a negative impact on health conditions. These findings correspond to results in humans and might strengthen the hypothesis that the response of the porcine gut microbiota to a specific dietary modulation is in support of using the pig as suitable animal model for humans to assess diet-gut-microbiota interactions. Data are available via ProteomeXchange with identifier PXD003447.
Assuntos
Dieta com Restrição de Gorduras , Dieta Hiperlipídica , Microbioma Gastrointestinal , Animais , Bifidobacterium , Butiratos/química , Impressões Digitais de DNA , DNA Bacteriano/isolamento & purificação , Fibras na Dieta/metabolismo , Faecalibacterium , Ácidos Graxos Voláteis/metabolismo , Fezes , Dosagem de Genes , Lactobacillus , Masculino , Modelos Animais , Oligonucleotídeos/genética , Proteômica , Distribuição Aleatória , Reação em Cadeia da Polimerase em Tempo Real , SuínosRESUMO
To further elaborate interactions between nutrition, gut microbiota and host health, an animal model to simulate changes in microbial composition and activity due to dietary changes similar to those in humans is needed. Therefore, the impact of two different diets on cecal and colonic microbial gene copies and metabolic activity, organ development and biochemical parameters in blood serum was investigated using a pig model. Four pigs were either fed a low-fat/high-fiber (LF), or a high-fat/low-fiber (HF) diet for seven weeks, with both diets being isocaloric. A hypotrophic effect of the HF diet on digestive organs could be observed compared to the LF diet (p < 0.05). Higher gene copy numbers of Bacteroides (p < 0.05) and Enterobacteriaceae (p < 0.001) were present in intestinal contents of HF pigs, bifidobacteria were more abundant in LF pigs (p < 0.05). Concentrations of acetate and butyrate were higher in LF pigs (p < 0.05). Glucose was higher in HF pigs, while glutamic pyruvic transaminase (GPT) showed higher concentrations upon feeding the LF diet (p < 0.001). However, C-reactive protein (CRP) decreased with time in LF pigs (p < 0.05). In part, these findings correspond to those in humans, and are in support of the concept of using the pig as human model.
Assuntos
Dieta com Restrição de Gorduras , Fibras na Dieta/uso terapêutico , Modelos Animais de Doenças , Disbiose/prevenção & controle , Animais , Bacteroides/classificação , Bacteroides/crescimento & desenvolvimento , Bacteroides/isolamento & purificação , Bacteroides/metabolismo , Bifidobacterium/classificação , Bifidobacterium/crescimento & desenvolvimento , Bifidobacterium/isolamento & purificação , Bifidobacterium/metabolismo , Biomarcadores/sangue , Ceco/microbiologia , Ceco/patologia , Colo/microbiologia , Colo/patologia , Cruzamentos Genéticos , Dieta Hiperlipídica/efeitos adversos , Fibras na Dieta/deficiência , Fibras na Dieta/metabolismo , Disbiose/metabolismo , Disbiose/microbiologia , Disbiose/patologia , Enterobacteriaceae/classificação , Enterobacteriaceae/crescimento & desenvolvimento , Enterobacteriaceae/isolamento & purificação , Enterobacteriaceae/metabolismo , Fermentação , Conteúdo Gastrointestinal/microbiologia , Mucosa Intestinal/microbiologia , Mucosa Intestinal/patologia , Masculino , Tipagem Molecular , Orquiectomia/veterinária , Tamanho do Órgão , Distribuição Aleatória , Sus scrofaRESUMO
The bacteria of the intestine have to cope with varying osmotic conditions in their ecosystem. In this in vitro study, the modified Hohenheim gas test (HGT) was used to determine fermentation activity and bacterial composition of pig's faecal microbial inoculum, when fermenting different carbohydrates (inulin, corn starch, potato starch, cellulose, pectin), under normal buffered and osmotic stress conditions (elevated medium salinity). After 24 h of fermentation, gas, ammonia and short-chain fatty acid (SCFA) production was measured, and the cell numbers of total eubacteria, Lactobacillus spp., Bifidobacterium spp. and enterobacteria were analysed, using real-time polymerase chain reaction. There was a significant reduction in gas production after 24 h when comparing osmotic stress conditions with normal buffered conditions, and there were also differences among carbohydrates under both conditions. The content of SCFA was significantly lower when comparing osmotic stress with normal buffered conditions. Under osmotic stress, inulin and corn starch increased (p < 0.05) cell numbers of total eubacteria, while Bifidobacterium spp. and enterobacteria were higher (p < 0.05) when corn starch and pectin were fermented, respectively, in comparison to the other carbohydrates. The in vitro system of the modified HGT appears to be suitable to scrutinise effects of carbohydrates on the metabolic activity and composition of the microbial community under osmotic stress conditions, as they might occur during situations of osmotic diarrhoea.
Assuntos
Carboidratos da Dieta/farmacologia , Fermentação/fisiologia , Concentração Osmolar , Probióticos , Suínos , Amônia/metabolismo , Ração Animal , Fenômenos Fisiológicos da Nutrição Animal , Animais , Bactérias/metabolismo , Dieta/veterinária , Ácidos Graxos Voláteis/metabolismo , Fezes/microbiologia , Aditivos Alimentares/farmacologia , Trato Gastrointestinal/química , Trato Gastrointestinal/microbiologia , MasculinoRESUMO
This study was conducted to estimate dietary threshold levels for crude protein (CP) and amino acids (AA) at which apparent ileal digestibilities (AID) of CP and AA in assay diets for newly weaned pigs reach plateaus. A total of 14 (12 + 2 for replacement) three-week old barrows were fitted with simple T cannulas at the distal ileum. Corn starch-based diets containing six graded levels of CP from casein, 90, 155, 220, 285, 350, or 415 g CP/kg assay diet (as-fed), were formulated. At 28 days of age, the pigs were randomly allocated to the six dietary treatments with two pigs per CP level in four weekly repeated measurement periods. They were fed twice daily a total of 30 g (as-fed) per kg of individual body weight at 8:00 and 20:00 h. The dietary CP and AA levels affected AID of CP and most AA (p = 0.005 to p = 0.040) in the assay diets. The AID of CP and AA were higher at 155 and 220 compared to 90 g CP/kg assay diet (p < 0.001 to p = 0.047). Initially, the AID of CP and AA increased sharply then gradually reached, at individual break points (p < 0.001 to p = 0.047), their plateaus (p < 0.001), which did not change up to dietary CP levels of 415 g/kg assay diet and the AID values became independent of the dietary AA levels. The piglets' capacity to digest CP and absorb AA was not limiting under these experimental conditions. There was no effect of age on AID of CP and AA (p = 0.056 to p = 0.899) except for a linear increase (p = 0.045) in AID of glycine from Period 1 to 4. Segmented quadratic with plateau relationships between the AID of CP and AA and their dietary contents were fitted for CP and each AA. The lower end points of 95% confidence intervals of the plateau AID values were defined to represent the initial plateau AID. The dietary CP and AA contents, corresponding to the initial plateau AID values, represent the dietary threshold levels. For CP and the indispensable amino acids, the plateau AID [%] and the dietary threshold levels [g/kg DM], respectively, in casein were: CP, 94.2 and 176; arginine, 95.1 and 7; histidine, 96.0 and 5; isoleucine, 96.4 and 8; leucine, 96.8 and 16; lysine, 96.8 and 12; methionine, 97.9 and 5; phenylalanine, 96.2 and 10; threonine, 93.4 and 9; tryptophan, 94.3 and 2; valine, 95.9 and 11. For the determination of plateau AID in piglets, the crude protein and amino acid contents in the assay diets should meet or exceed the corresponding dietary threshold levels.
Assuntos
Ração Animal/análise , Dieta/veterinária , Proteínas Alimentares/análise , Digestão/fisiologia , Íleo/fisiologia , Suínos/fisiologia , Aminoácidos/análise , Animais , Caseínas/química , Masculino , DesmameRESUMO
A balance experiment was carried out to investigate the effects of betaine monohydrate (BET) or betaine derived from condensed molasses solubles (CMS) as a substitute for methionine and choline on nitrogen (N) balance and total tract nutrient digestibility in weaned piglets. The experiment included four treatments with 32 barrows with an average initial body weight (BW) of 13.5 kg. The supplementation of DL-methionine and choline (positive control = PC) to the basal diet, which was deficient in methionine and low in compatible osmolytes in the form of betaine or its precursor choline (negative control = NC) resulted in a significant increase in N retention of 0.8 g/d. The substitution of DL-methionine and choline with BET or CMS did not affect N retention compared to the PC and the NC treatment either. Feeding the PC diet increased the digestibilities of organic matter, NDF, ADF, NFE, crude ash, Ca, P, methionine, tryptophan and cystine by 1.9%, 7.3%, 9.7%, 1.1%, 6.3%, 13.9%, 7.7%, 15.9%, 4.3% and 2.8%, respectively, and tended (p < 0.20) to increase the digestibilities of most other amino acids by 1.6-3.4%. Digestibility of CP, EE (HCl), Mg and Na was 3.1% (p=0.09), 5.1% (p=0.09), 5.1% (p= 0.06) and 3.3% (p= 0.17) higher, respectively, when compared to the NC treatment. BET and CMS supplementation increased most nutrient digestibilities in the same magnitude as for the PC treatment. In summary, the supplementation of betaine, originating from different sources, to a diet with low contents of compatible osmolytes increased in particular the fermentation of fibre and enhanced mineral absorption. The supplementation of the NC with DL-methionine was more efficient in improving N retention than the replacement of DL-methionine by betaine originating from BET or CMS.