The influence of Lentinus edodes (Shiitake mushroom) preparations on bacteriological and morphological aspects of the small intestine in piglets.

Among substances intended to replace growth promoting antibiotics in pig nutrition, non-digestible oligosaccharides or polysaccharides could be potential alternative compounds. Therefore, the influence of beta-1,3-1,6 glucans on bacteriological, biochemical and morphological aspects of the small intestine in weaned piglets was investigated. As sources of beta-glucans, Lentinan (extract of Lentinus edodes mycelium) or dried L. edodes mycelium were added to the diet. Four homogenous groups of 5 newly weaned piglets (4 weeks of age) received one of four diets: control diet (C), C supplemented with Avilamycin (50 mg/kg, positive control), C supplemented with 0.1% of Lentinan and C supplemented with 5% of dried L. edodes mycelium powder. A first group of 10 piglets was euthanized after 11 days and the remaining 10 on day 12 of the experiment. The gastrointestinal tract was divided in segments and samples taken from digesta (stomach, proximal and distal jejunum, caecum), mucosal scrapings (jejunum) and ring shaped tissue samples (1 cm) of proximal and distal jejunum. Bacterial counts were made with digesta and mucosal samples, and short-chain fatty acids (SCFA), lactic acid and ammonia concentrations were determined. Tissue samples of both jejunal sites were embedded in paraffin wax for morphometrical (villus length, crypt depth) and histological observations (numbers of intraepithelial lymphocytes (IEL), goblet cells, apoptotic enterocytes on villi, mitotic cells in crypts). Only the diet containing 5% of dried L. edodes consistently resulted in lower viable counts (ca. 1-2 log10 CFU) of total bacteria, E. coli, streptococci and lactic acid bacteria, and luminal and mucosal effects agreed very well. With this diet, acetate and butyrate concentrations in the distal jejunum were doubled, which is favourable in view of the trophic effect on enterocytes and colonocytes. Villus length (V) was increased with both diets containing beta-glucans while crypt depth (C) was not altered, but V/C was higher. IEL counts were decreased by both diets although bacterial numbers, which is only one parameter of bacterial load, were only diminished with the L. edodes feed. The three supplemented feeds lowered the number of apoptotic enterocytes on the villi, but these numbers were very low (control diet : 44 cells per 100 villi), making clear interpretation difficult. The mitotic index was slightly lower with the L. edodes feed, although not statistically significant. Decreased viable counts observed with the latter diet is a favourable effect as it is accepted that a lower bacterial load causes lower turnover rates of the intestinal epithelial cells, while there is also less competition for specific substrates. A higher V/C ratio, a smaller number of IEL in the epithelium and a lower apoptotic index also indicate slower turnover rate of the mucosa when Lentinan and L. edodes diets were fed. The inconsistent effects observed with Lentinan were probably due to the low amount added to the diet. It should be taken into account that the influence of L. edodes mycelium powder was more likely due to the presence of antibacterial compounds (eg. lenthionine, lentinamycin, terpenoids, polyphenols), rather than to an immunostimulating action of beta-glucans with increased release of IgA onto the mucosa surface.     

De ovicide werking van 3,5-Dinitro-O-Cresol

Conclusies De toxiciteit van dinitro-o-cresol-oplossingen moet toegeschreven worden aan de giftige werking van ongedissocieerde diniţro-o-cresol-moleculen. Aangezien een zure oplossing van deze stof veel meer ongedissocieerde zuurmoleculen bevat dan een alkalische, is de giftige werking van dit toxicans sterk afhankelijk van de pH der oplossing. Er is een sterke evenredigheid geconstateerd tusschen de hoeveelheid aanwezige dinitro-o-cresol-moleculen in oplossingen van verschillende pH en de toxische werking ervan op meelmoteieren en op bladluiseieren. De hooge toxische werking van deze moleculen komt zoowel in waterige oplossing als gecombineerd met minerale olie naar voren, zoodat in beide gevallen de pH de belangrijkste factor vormt voor het toxische effect van de vloeistof. Aan de dinitro-o-cresolaat-ionen moet waarschijnlijk geen toxische werking worden toegeschreven, evenmin aan ongedissocieerde dinitro-o-cresolaat-moleculen. Van de vier onderzochte alkalizouten van dinitro-o-cresol is het ammoniumzout toxischer dan het kalium-, natrium- en lithiumzout, welke drie laatste een even groote werking uitoefenen. De hoogere toxiciteit van het ammoniumzout moet waarschijnlijk ook teruggebracht worden tot de werking van ongedissocieerde dinitro-o-cresol-moleculen. Voor de nieuwe gezichtspunten, welke dit onderzoek voor de bereiding van sproeimiddelen heeft opgeleverd, werden octrooien aangevraagd. Publicatie van het Laboratorium der N.V. De Bataafsche Petroleum Maatschappij te Amsterdam, afdeeling Plantenziektenbestrijdingsmiddelen     

In vitro dose–response of carvacrol, thymol, eugenol and trans-cinnamaldehyde and interaction of combinations for the antimicrobial activity against the pig gut flora

In vitro simulations of the gastric and small intestinal fermentation with varying doses of carvacrol, thymol, eugenol and trans-cinnamaldehyde and binary combinations thereof were carried out to calculate dose–response equations for the antimicrobial effect against the main pig gut flora components. Interaction effects were evaluated following the isobole method. In gastric simulations eugenol and trans-cinnamaldehyde showed clearly less inhibitory activity towards lactobacilli than carvacrol and thymol, which could also be observed in the small intestinal simulations. The minimum concentration for carvacrol, thymol, eugenol and trans-cinnamaldehyde in small intestinal simulations to reduce the number of total anaerobic bacteria compared to control with a probability of 99.7% was 255, 258, 223 and 56 mg/l respectively. This strong activity of trans-cinnamaldehyde was due to its effect against coliform bacteria; a dose of 104 mg/l gave a reduction of 1 log CFU/ml vs. 371, 400 and 565 mg/l for carvacrol, thymol and eugenol respectively. Few combinations demonstrated synergism; most mixtures showed zero interaction or antagonism. Only carvacrol + thymol was slightly synergistic.     

Intact brown seaweed (Ascophyllum nodosum) in diets of weaned piglets: effects on performance, gut bacteria and morphology and plasma oxidative status

The aim was to assess the effects of intact dried Ascophyllum nodosum seaweed on piglet performances, gut bacteria and function and plasma oxidative status. A total of 160 weaned piglets (21 days, 6.59 ± 0.91 kg) were allocated to four dietary treatments with eight pen replicates of five animals each for 28 days: a control diet; based on cereals, soybean meal and milk products, and three basal diets supplemented with either 2.5, 5.0 or 10.0 g dried seaweed per kg. At day 12/13 one piglet from each pen was sacrificed. Plasma samples were taken to determine parameters of oxidative status. Digesta were sampled for microbiological plate countings onto selective media and molecular analysis using PCR‐DGGE. Small intestinal tissue was taken for morphological and electro‐physiological determinations. Data were analysed by a linear model with treatment as fixed effect. A. nodosum supplementation had no effect on daily weight gain, nor did it alter feed conversion ratio. Plate countings failed to reveal differences among treatments. Dendograms prepared using PCR‐DGGE banding patterns did not indicate clustering of microbial profiles based on diet supplement. Plasma oxidative status and outcome of morphology and of electro‐physiological measurements from gut tissues were similar for all treatments. Thus, the addition of A. nodosum seaweed to well digestible diets did not enhance performances of piglets nor some gut health parameters and plasma oxidative status.     

The combined use of whole Cuphea seeds containing medium chain fatty acids and an exogenous lipase in piglet nutrition.

In search for an alternative for nutritional antimicrobials in piglet feeding, the effects of adding whole Cuphea seeds, as a natural source of medium chain fatty acids (MCFA), with known antimicrobial effects, and an exogenous lipase to a weaner diet were studied. The foregut flora, the gut morphology, some digestive parameters and the zootechnical performance of weaned piglets were investigated. Thirty newly weaned piglets, initial weight 7.0 +/- 0.4 kg, were divided according to litter, sex and weight in two groups (control diet; Cuphea + lipase diet). The Cuphea seeds (lanceolata and ignea) (50 g kg(-1)) were substituted for soybean oil (15 g kg(-1)), Alphacell (25 g kg(-1)) and soy protein isolate (10 g kg(-1)) in the control diet. Also 500 mg kg(-1) microbial lipase was added to the Cuphea diet. The piglets were weighted individually on days 0, 3. 7, 14 and 16. Feed intake was recorded per pen during days 0 to 3, 3 to 7, 7 to 14 and 14 to 16. On day 7 five piglets of each experimental group were euthanized for counting the gastric and small intestinal gut flora and for gut morphology at two sites of the small intestine (proximal, distal). The results indicate a trend towards improved performances parameters by feeding Cuphea + lipase. The enzymic released MCFA (1.7 g kg(-1) fresh gastric contents) tended to decrease the number of Coliforms in the proximal small intestine, but increased the number in the stomach and distal small intestine. With Culphea, the number of Streptococci was significantly lower in small intestine, but not in the stomach, while the number of Lactobacilli was significantly lower in the distal small intestine and tended to be lower in the stomach and proximal small intestine. No differences between the diets were noted for the total anaerobic microbial load in the stomach or in the gut. Feeding Cuphea + lipase resulted in a significantly greater villus height (distal small intestine) and a lesser crypt depth (proximal and distal small intestine) and greater villus/crypt ratio depth (proximal and distal small intestine). The intra-epithelial lymphocyte (IEL) counts per 100 enterocytes were significantly decreased in the proximal small intestine and tended to decrease in the distal small intestine by feeding the Cuphea + lipase diet. Both phenomena are indicative for a more healthy and better functional state of the mucosa. Present results are in line with foregoing research, showing that manipulation of the gut ecosystem by the enzymic in situ released MCFA in the stomach and foregut can result in improved performances of the piglets, which makes the concept a potential alternative for in-feed nutritional antibiotics.     

Screening of two probiotic products for use in fermented liquid feed

In this trial two commercial probiotic products (Bactocell® and Adjulact® Pro) were investigated in vitro for their use as microbial inoculum for the production of fermented liquid feed (FLF) for pigs. Bactocell® was applied at a dose of 9 and 10 log₁₀ CFU/kg and Adjulact® Pro at a level of 9 log₁₀ CFU/kg. The FLF (control and treatments) was prepared with a water to feed ratio of 4:1 and run in batch for 72 h at 30 °C. The microbial population was followed with plate countings and the lactic acid, acetic acid and ethanol concentration was determined at different time points in the FLF. After 24 h, significant differences (P < 0.05) were found between the control and the Adjulact® Pro FLF for pH (4.7 vs 4.3), lactic acid (57.9 vs 91.5 mmol/L), acetic acid (23.1 vs 6.8 mmol/L), ethanol (24.5 vs 1.1 mmol/L), coliforms (7.2 vs 4.3 log₁₀ CFU/mL) and E. coli (6.2 vs 4.4 log₁₀ CFU/mL). Bactocell® addition did not alter the fermentation characteristics compared to the control FLF. After 72 h no significant differences between treatments were noted, except for the yeast count which was higher in the FLF inoculated with Adjulact® Pro.     

Factoren,welke van belang zijn bij de beoordeling van de mate der spintbestrijding door wintersproeimiddelen

Summary In laboratory trials with ovicidal sprays on red spider winter eggs it was found that these sprays retarded the hatching of the eggs, that were not killed by the spray. In orchardspraying during wintertime the same phenomena was seen. A very poor acting oil emulsion was chosen so as to demonstrate the effect mentioned above more clearly. On the sprayed trees the hatching of the eggs was much delayed compared with the check trees; this was especially the case in the first period of hatching. If a count had been made only at this period the kill of the eggs by the winterspray would have been 80–90% compared with the checks. If the counts were made at a later date one would only find a kill of 30–40% compared with the check.These facts demonstrate the absolute necessity of several countings if big mistakes will be avoided.The delayed hatching of the winter eggs of red spider seems to be due to the stage of development of the eggs at the time of spraying. The further the development the more sensitive are the eggs.     

Neospora caninum and Toxoplasma gondii in brain tissue of feral rodents and insectivores caught on farms in the Netherlands

We investigated the presence of both Neospora caninum and Toxoplasma gondii in 250 brain tissue samples from 9 species of feral rodents and insectivores caught on 10 organic farms in the Netherlands in 2004. Collected samples were conserved in 4% paraformaldehyde solution and analysed by real-time PCR. For N. caninum, 31 samples originating from 6 species tested positive (12.4%): common shrews (33.3%), wood mice (17.6%), harvest mice (16.7%), house mice (15.4%), white-toothed shrews (10.8%) and common voles (4.2%). For T. gondii, the overall contamination level was 4%, and only three species were found to be positive: house mice (9.0%), common voles (4.2%) and white-toothed shrews (2.0%). Most N. caninum infected samples (27/31; 87%) were found on farms where dogs were present. Due to the observation that rodents and insectivores can contract both parasites, they might function as indicator species for the parasitic load on farms.     

Influence of virginiamycin on the digestive physiology in precaecal re-entrant cannulated pigs.

The present experiment was set up to study the effect of Virginiamycin, a nutritional growth promoting antibiotic, on the digestive physiology using precaecal cannulated pigs. The semipurified diet used provided 21% protein and 60% of nitrogen free extract (NFE), 2/3 as starch and 1/3 as lactose. Due the older age of the pigs, the lactose induced some degree of malabsorption as precaecal flow rate of digesta was markedly higher (3.2 kg/d) compared with published data obtained with purified diets without lactose. This was also reflected in the rather low ileal digestibility of the nutrients (%): dry matter 68.6, protein 79.6, fat 78.4 and NFE 75.0. Virginiamycin markedly lowered flow rate (2.2 kg/d) and significantly improved apparent precaecal digestibilities (%): dry matter 74.0, protein 81.4, fat 81.9 and NFE 78.7. The faecal apparent digestibility was comparable with published data. There were no treatment differences indicating that precaecal digestibilities are much more sensitive then faecal ones. In order to explain the differences obtained the mean retention time in the upper intestine was measured. Although significant differences were noted (control: 5 h, Virginiamycin: 6 h) a direct cause-effect relationship was not evident. Also the activity of selected pancreatic enzymes in ileal contents was compared. There were no consistent differences between the two treatments, except for a lower lipase activity during Virginiamycin treatment.