In vitro assessment of gastrointestinal tract (GIT) fermentation in pigs: Fermentable substrates and microbial activity

Recently, it has become apparent that GIT fermentation is not only of interest for ruminant animals, but also for monogastrics. While it is now widely accepted that the fermentation process and its resultant end-products can have important influences on animal health, little is known about the microbiological and immunological processes involved. In terms of animal health, most interest at the moment is focussed on those moments in animals’ lives when they are faced with sudden changes resulting in stress. The period of weaning in piglets is a typical example of this. The most easily accomplished and appropriate way to influence GIT fermentation processes is that of dietary intervention. This is reflected by the widespread interest in so-called pre- and pro-biotics. Given the complexities of the interactions occurring in the animal itself, it is hardly surprising that in vitro techniques are being widely used: firstly to examine potential substrates for their fermentability and possible inclusion in diets, and secondly, to assess changes in the microbial populations in response to these substrates. This paper will review the techniques currently in use for these two aspects of monogastric fermentation, and provide examples of their use

Tolerance and safety evaluation of N, N-dimethylglycine, a naturally occurring organic compound, as a feed additive in broiler diets

N,N-dimethylglycine (DMG) is a tertiary amino acid that naturally occurs as an intermediate metabolite in choline-to-glycine metabolism. The objective of the present trial was to evaluate tolerance, safety and bioaccumulation of dietary DMG in broilers when supplemented at 1 g and 10 g Na-DMG/kg. A feeding trial was conducted using 480 1-d-old broiler chicks that were randomly allocated to twenty-four pens and fed one of three test diets added with 0, 1 or 10 g Na-DMG/kg during a 39 d growth period. Production performance was recorded to assess tolerance and efficacy of the supplement. At the end of the trial, toxicity was evaluated by means of haematology, plasma biochemistry and histopathology of liver, kidney and heart (n 12), whereas bioaccumulation was assessed on breast meat, liver, blood, kidney and adipose tissue (n 8). Carcass traits were similar between the control and 1 g Na-DMG/kg feed groups (P.0·05), but the feed:gain ratio was significantly improved at 1 g Na-DMG/kg feed compared with the control or the 10-fold dose (P¼0·008). Histological examinations showed no pathological effects and results of haematology and plasma biochemistry revealed similar values between the test groups (P.0·05). Bioaccumulation occurred at the 10-fold dose, but the resulting DMG content in breast meat was comparable with, for instance, wheat bran and much lower than uncooked spinach. In conclusion, DMG at 1 g Na-DMG/kg improved the feed:gain ratio in broilers without DMG being accumulated in consumer parts. Furthermore, dietary supplementation with DMG up to 10 g Na-DMG/kg did not induce toxicity or impaired performance in broilers

Piyanist Gülay Uğurata öldü

Taha Toros Arşivi, Dosya No: 150-Gülay Uğurat

Alternatives to the use of antibiotics as growth promoters for monogastric animals

Recently, more and more is becoming known about the mode of action of antibiotics as growth promoters (AMGP), particularly in relation to the development of microbial resistance. Consequently, the use of these AMGP is already restricted or forbidden in many countries. Therefore, to compensate for the possible decrease in production, a lot of work is now being done to investigate possible alternatives. Suitable alternatives must be both proven and cost-effective, for the conditions and diets as used at the farm level

An in vitro batch culture method to assess potential fermentability of feed ingredients for monogastric diets

Interest in fermentation within the monogastric digestive tract is growing, particularly relative to animal health. This is of particular importance in relation to the forthcoming European ban on inclusion of anti-microbial growth promotors in animal diets. Fermentable carbohydrates are recognized as having an important role in fermentation in the monogastric digestive tract, and are often added to diets without having been examined for their actual fermentability, particularly in relation to the target animal. We describe an in vitro method to assess feed ingredients, as potential components of monogastric diets, which stimulate a positive fermentation (i.e., ones which will be well fermented and produce more short-chain fatty acids (SCFA) and less ammonia). This technique requires use of a batch culture containing the test substrate and an inoculum of appropriate origin. During fermentation, cumulative gas production is measured at regular intervals, as an indicator of kinetics of the reaction. When fermentation is complete, organic matter losses and end-products such as SCFA and ammonia, are measured. This paper illustrates use of the technique with 45 carbohydrate-based ingredients using faeces from unweaned piglets as inoculum. By assessing potential fermentability of a large number of ingredients, it is possible to make an informed choice as to which substrates are most suited for inclusion in a diet. By combining results with information about transit time, diets can be designed which should stimulate desirable fermentation along the entire digestive tract. In vitro fermentability is a potentially valuable characteristic in diet design, in order to stimulate microbial activity in the digestive tract

Differences in microbial activity of digesta from three sections of the porcine large intestine according to in vitro fermentation of carbohydrate-rich substrates

To determine whether faecal microorganisms can represent the entire large intestinal population, samples from caecum, mid-colon and rectum of three adult pigs were used for the in vitro fermentation of fructo-oligosaccharide (FOS), potato starch, wheat bran and oat hulls. The cumulative gas production technique measured fermentation kinetics and end-products such as total gas, NH3 and volatile fatty acids (VFA). There were significant differences in the fermentability of substrates, in terms of both kinetics and end-products. More relevant to this study, there were also differences between pigs in respect of total gas production, the rate of gas production (RM) and VFA production. For large intestine sections, there were more VFA from mid-colon and rectal inocula compared with that from the caecum (p < 0.0001). Total gas, RM and NH3 were highest for rectal, intermediate for mid-colon and lowest for caecal inocula (p < 0.0001). It was concluded that, while faecal sampling might overestimate caecal fermentation, its use is valid for in vitro assessment of large intestinal fermentation. However, differences between pigs indicate that a mix of samples from several animals remains important. Copyright © 2004 Society of Chemical Industr

In vitro fermentation kinetics of some non-digestible carbohydrates by the caecal microbial community of broilers

Fermentable carbohydrates can lead to changes in the gut microflora, which may have positive consequences for health. However, often, ingredients are added to diets without prior investigating about their potential fermentability within the target animal. The experiment reported, was conducted to investigate the fermentation kinetics of some non-digestible carbohydrates (NDC) by the caecal microbial community of broiler chickens by an assessment of the cumulative gas production during fermentation of each substrate. It also aimed to study changes in the microbial community, following fermentation of these non-digestible carbohydrates, by use of polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE). Four extracted non-digestible carbohydrates (ENC): soybean meal oligo- and water-soluble polysaccharides (SMO and SMP), alfalfa meal oligo- and water-soluble polysaccharides (AMO and AMP) were studied. Two pure sugars, raffinose (RAF) and stachyose (STA) were also included. To assess the fermentability of the substrates, cumulative gas pressure was monitored continuously, for 72 h, and at the end of fermentation, pH, volatile fatty acid (VFA), and ammonia (NH3) concentrations were measured in the fermentation solution. The PCR-DGGE technique was applied to compare microbial DNA fingerprints between substrates at the end of the fermentation. The inoculum for the in vitro gas production was obtained from a mixture of caecal contents of forty 81-day-old broiler birds. Soy oligosaccharides led to significantly more butyric acid production (P60–80%) between some of the substrates. It was concluded that SMO, SMP, AMO and AMP, as well as RAF and STA were significantly different, both in terms of their fermentation kinetics and end-products using caecal contents from adult broilers. The extent to which these non-digestible, but fermentable, carbohydrates could change the microbial community of the broiler caecum, either in terms of the species detected, or its activity, needs to be investigated further, and then related to its effect on gut health in the animal itsel

A functional polymeric immunoglobulin receptor in chicken (Gallus gallus) indicates ancient role of secretory IgA in mucosal immunity.

Animals are continuously threatened by pathogens entering the body through natural openings. Here we show that in chicken ( Gallus gallus ), secretory IgA (sIgA) protects the epithelia lining these natural cavities. A gene encoding a chicken polymeric Ig receptor ( GG-pIgR ), a key component of sIgA, was identified, and shown to be expressed in the liver, intestine and bursa of Fabricius. All motifs involved in pIgR function are present, with a highly conserved Ig-binding motif in the first Ig-like domain. Physical association of GG-pIgR with pIgA in bile and intestine demonstrates that this protein is a functional receptor. Thus, as shown for mammals, this receptor interacts with J-chain-containing polymeric IgA (pIgA) at the basolateral epithelial cell surface resulting in transcytosis and subsequent cleavage of the pIgR, releasing sIgA in the mucosal lumen. Interestingly, the extracellular portion of GG-pIgR protein comprises only four Ig-like domains, in contrast with the five domain structure found in mammalian pIgR genes. The second Ig-like domain of mammalian pIgR does not have an orthologous domain in the chicken gene. The presence of pIgR in chicken suggests that this gene has evolved before the divergence of birds and reptiles, indicating that secretory Igs may have a prominent role in first line defence in various non-mammalian species