E. Święch

The effects of supplementing a low-protein threonine-deficient diet with different sources of non-essential amino acids on nitrogen retention and gut structure in young pigs

A threonine-adequate control diet and four Thr-deficient (80% of requirement) diets were formulated to contain similar amounts of digestible lysine and the recommended pattern of other standardised ileal digestible essential amino acids (except Thr). Threonine-deficient diets were supplemented with different amounts and sources of non-essential amino acids, namely 0, 20, and 40 g wheat gluten (WG) protein per kg diet or 17.6 g monosodium glutamate (MSG) per kg diet. Each diet was fed for 28 days to six piglets (initial BW 15 kg). Supplementation of the Thr-deficient diet with WG or MSG had a positive effect on N retention (5.9–8.5%) in younger, but not in older, pigs. Furthermore, it reduced the plasma Thr level and increased threonine dehydrogenase activity in the liver and pancreas. The treatment effects on intestinal morphology differed according to the histological criteria used. It may be concluded that non-essential amino acids added to the low-protein diet deficient in Thr seem to improve utilisation of these amino acids for protein deposition in very young pigs, whereas their effects on the structure of the small intestine are equivocal.

Interactive effects of protein and carbohydrates on production of microbial metabolites in the large intestine of growing pigs

ABSTRACT The study aimed at determining the effect of protein type and indigestible carbohydrates on the concentration of microbial metabolites in the large intestine of pigs. The experiment involved 36 pigs (15 kg initial body weight) divided into six groups, fed cereal-based diets with highly digestible casein (CAS) or potato protein concentrate (PPC) of lower ileal digestibility. Each diet was supplemented with cellulose, raw potato starch or pectin. After 2 weeks of feeding, pigs were sacrificed and samples of caecal and ascending, transverse and descending colon digesta were collected for analyses of microbial metabolites. PPC increased the concentration of ammonia, p-cresol, indole, n-butyrate, isovalerate and most of the amines in comparison with CAS. Pectin reduced the production of p-cresol, indole, phenylethylamine and isovalerate in the large intestine compared with potato starch. Starch and pectin increased mainly the concentration of n-butyrate and n-valerate in the colon compared to cellulose. Interaction affected mainly amines. Feeding PPC diet with potato starch considerably increased putrescine, cadaverine, tyramine and total amines concentrations compared with PPC diets with pectin and cellulose, whereas feeding CAS diet with starch reduced their concentrations. There was also a significant effect of interaction between diet and intestinal segment on microbial metabolites. In conclusion, PPC intensifies proteolysis in the large intestine and also n-butyrate production. Raw starch and pectin similarly increase n-butyrate concentration but pectin inhibits proteolysis more efficiently than starch. The interactive effects of both factors indicate that pectin and cellulose may beneficially affect fermentative processes in case of greater protein flow to the large intestine.

The effect of dietary level of two inulin types differing in chain length on biogenic amine concentration, oxidant-antioxidant balance and DNA repair in the colon of piglets

The effect of dietary level of two types of inulin on amine concentration, redox status and DNA glycosylase activity in the colon of piglets was investigated. Seven groups of piglets were fed diets without inulin addition (control) or with 1%, 2% or 3% inulin with an average degree of polymerisation of 10 (IN10) or 23 (IN23) for 40 days. The 2% and 3% IN10 diets increased tryptamine concentration in the proximal colon, while methylamine concentration in the distal colon was increased by the 1% and 3% IN10 diets. The 1% and 2% IN23 diets increased phenylethylamine and methylamine concentration in the proximal colon, respectively, while 1,7-diaminoheptane content was increased by both diets. Its concentration in the middle and distal colon was increased by the 1% and 2% IN23 diet, respectively. There was no improvement in the oxidant-antioxidant balance in colonic digesta of piglets fed IN10 and IN23 diets. Piglets fed IN10 diets had lower 1,N6-etheno-2’-deoxyadenosine excision activity in each colon segment, as compared with the control group. It was also reduced by the 2% and 3% IN23 diets in the proximal colon, while in the middle and distal colon by all IN23 diets. Feeding all IN10 and IN23 diets reduced 3,N4-etheno-2’-deoxycytidine and 8-oxo-deoxyguanosine excision activities in each colon segment. Feeding IN10 and IN23 diets neither decreased amine concentrations nor improved the oxidant-antioxidant balance in colonic digesta of piglets. However, both types of inulin efficiently reduced the activity of DNA repair enzymes.

Effect of Replacing Soybean Meal by Raw or Extruded Pea Seeds on Growth Performance and Selected Physiological Parameters of the Ileum and Distal Colon of Pigs

The use of pea seeds is limited due to the content of antinutritional factors that may affect gut physiology. Heat treatment such as extrusion may reduce heat-labile antinutritional factors and improve the nutritional value of pea seeds. This study determined the effect of partial replacement of soybean meal in pig diets by raw or extruded pea seeds on growth performance, nitrogen balance and physiology of the ileum and distal colon. The experiment was carried out in 18 castrated male piglets of initial body weight of 11 kg, divided into three groups. The animals were fed cereal-based diets with soybean meal (C), which was partly replaced by raw (PR) or extruded pea (PE) seeds. Nitrogen balance was measured at about 15 kg body weight. After 26 days of feeding, tissue samples were taken from the ileum and distal colon for histological measurements, and colonic digesta samples for analyses of microbial activity indices. The animals fed the PE diet had a significantly greater average daily gain than those fed the C diet and better apparent protein digestibility than those on the PR diet. Pigs fed the PR diet had a significantly greater butyric acid concentration and lower pH in the colon than pigs fed PE and C diets. There was no significant effect of the diet on other indices of microbial activity or morphological parameters. In conclusion, feeding a diet with extruded pea seeds improved growth performance of pigs, did not affect intestinal morphology and had a negligible effect on microbial activity in the distal colon.

Oral uricase eliminates blood uric acid in the hyperuricemic pig model

An elevated level of serum uric acid—hyperuricemia, is strongly associated with the development of gout and chronic kidney disease (CKD) which is often accompanied by a significantly reduced glomerular filtration rate (GFR). In the present study, we investigated the extra-renal elimination of uric acid via the intestine in a healthy pig model and the effect of oral uricase therapy on plasma uric acid concentrations in pigs with induced hyperuricemia and CKD. The experiment was conducted on eleven, ten-week-old pigs (n = 11). The porcine model of CKD was developed by performing 9/10 nephrectomy surgery on eight pigs. A stable model of hyperuricemia was established in only five of the eight nephrectomized pigs by frequent injections of uric acid (UA) into the jugular vein. All pigs (three healthy pigs and five CKD pigs) were operated for implantation of jugular vein catheters and the three healthy pigs also had portal vein catheters inserted. Blood uric acid concentrations were measured spectrophotometrically, using the Uric Acid Assay Kit (BioAssay Systems, Hayward, USA). The piglets with CKD received orally administered uricase (treatment) and served as their own controls (without uricase supplementation). Oral uricase therapy significantly decreased plasma uric acid concentrations in pigs with CKD, whereas hyperuricemia was observed in the pigs whilst not being treated with uricase. Urinary uric acid excretion was similar during both the treatment and control periods during the first 8 h and 24 h after UA infusions in the CKD pigs. To demonstrate the elimination of UA via the intestine, the healthy pigs were infused with UA into the jugular vein. The blood collected from the jugular vein represents circulating UA concentrations and the blood collected from the portal vein represents the concentration of UA leaving the intestine. The final (after 2 h) concentration of UA was significantly lower in blood collected from the portal vein compared to that collected from the jugular vein (3.34 vs. 2.43 mg/dL, respectively, p = 0.024). The latter allows us to suggest that UA is eliminated from the blood via the gut tissue.

Alternative prediction methods of protein and energy evaluation of pig feeds

Precise knowledge of the actual nutritional value of individual feedstuffs and complete diets for pigs is important for efficient livestock production. Methods of assessment of protein and energy values in pig feeds have been briefly described. In vivo determination of protein and energy values of feeds in pigs are time-consuming, expensive and very often require the use of surgically-modified animals. There is a need for more simple, rapid, inexpensive and reproducible methods for routine feed evaluation. Protein and energy values of pig feeds can be estimated using the following alternative methods: 1) prediction equations based on chemical composition; 2) animal models as rats, cockerels and growing pigs for adult animals; 3) rapid methods, such as the mobile nylon bag technique and in vitro methods. Alternative methods developed for predicting the total tract and ileal digestibility of nutrients including amino acids in feedstuffs and diets for pigs have been reviewed. This article focuses on two in vitro methods that can be used for the routine evaluation of amino acid ileal digestibility and energy value of pig feeds and on factors affecting digestibility determined in vivo in pigs and by alternative methods. Validation of alternative methods has been carried out by comparing the results obtained using these methods with those acquired in vivo in pigs. In conclusion, energy and protein values of pig feeds may be estimated with satisfactory precision in rats and by the two- or three-step in vitro methods providing equations for the calculation of standardized ileal digestibility of amino acids and metabolizable energy content. The use of alternative methods of feed evaluation is an important way for reduction of stressful animal experiments.

Effect of dietary protein and carbohydrates on phenolic compounds formation in the large intestine of pigs

Phenolic and indolic compounds, potentially toxic substances, are formed in the gut in bacterial degradation of the aromatic amino acids e.g. phenol, p-cresol and phenylpropionate originate from tyrosine, phenylacetate from phenylalanine and indole, indole propionate and indole acetate from tryptophan (Hughes et al., 2000). This process may be modified by feeding diet containing different carbohydrates and protein sources. The aim of the present study was to assess the influence of protein of animal or plant origin and three types of carbohydrates, used as an energy source for microflora, on the processes of aromatic amino acid degradation in the large intestine of pigs.

Microbial activity in the large intestine of chickens fed diets containing different sources of inulin-type fructans

Inulin-type fructans are water-soluble compounds of plant origin with varying length of polysaccharide chains, with β-2,1 fructosyl-fructose glycosidic bonds. This type of bond makes it resistant to enzymatic hydrolysis by small intestinal digestive enzymes (specific for α-glycosidic bonds). As a result, inulin fructans are indigestible by enzymes of animal origin and are fermented in the large intestine. The inulin fructans can be found in many plants, but by the industry is mainly extracted from chicory and Jerusalem artichoke. Maintaining animal welfare through the modulation of large intestine function may play an important role, therefore the aim of the study was to determine the effect of diets’ supplementation with different sources of inulin-type fructans on microbial activity in the large intestine of chickens.

Microbial activity in the large intestine of piglets fed diets with different sources of inulin

Inulin-type fructans are natural food ingredients present as storage carbohydrates in a number of plants. Currently only two species, both from Compositae family, i.e. chicory and Jerusalem artichoke are used by the industry for extraction of these compounds (Kaur and Gupta, 2002). Inulin-type fructans resist digestion by small intestinal enzymes of monogastric animals but are fermented in the large intestine (Roberfroid, 2005). Modulation of large intestine function plays an important role in maintaining animal welfare, therefore the aim of this study was to determine the effect of diets’ supplementation with different sources of inulin-type fructans on microbial activity in the large intestine of piglets.