Dox-al Australia - providing technical documents for the feed industry

The effect of the administration of THEPAX, compared to an antibiotic at two low dosages, has beentested on 90 veals, fed for 153 days with the same milk replacer. Daily weight gain, total and individual milk replacer's consumption, final weight and carcass yield at the slaughter house have been recorded and compared.

Feeding yeast to dairy cattle has become common place. Yeast cultures: the media and nutrients produced after the yeast have been fermented on a specific substrate. It contains some live yeast cells, however, the counts are usually variable and not guaranteed. In addition, the degree to which the yeast itself has been fermented on the sub-straight will dictate the relative proportion of yeast cells and media (substrate) that will be present in the product. In addition, the type of drying process and/or final product preparation (extrusion) can dictate the total count and viability of the yeast in the final product.

Colistin sulphate is chosen as the product is problematic in terms of its dust emission and in feed behavioural pattern. Colistin sulphate represents all problematic powdered premixes. Its behaviour is a guide to the behavioural patterns of al powdered stockfeed additives. Results on uniformity of dispersion and cross contamination in feed

An Australian prepared powdered olaquindox premix was mixed with feed with a target level of 100ppm. Similarly Enterodox 100 BMP, the patented micro granulated olaquindox 10% premix was added to feed at similar levels. The results indicated that powdered olaquindox was erratically dispersed throughout the feed mass with only 18% within accepted dosage limits and a CV of 78%. One hundred percent (100%) of the BMP treated olaquindox was within accepted dosage limits with a CV of around 5%

This is a discussion paper relating to the risks posed to workers from exposure to dust emissions from medicated feed additives at feed mill level and on farm. Special attention is paid to some products purporting to have a form of protection, but the inability of the Australian authorities to police such claims.

Mycotoxins are a diverse group of toxic secondary metabolites produced by certain moulds when they grow on agricultural products. They do not belong to a single class of chemical compounds, and they differ in their toxicological effects. Some mycotoxicosis, the toxic manifestations of mycotoxins in humans or animals, have been known for hundreds of years (e.g. ergotism).However, it was the outbreak of Turkey X disease in the United Kingdom during 1960, and the subsequent discovery of the aflatoxins and their toxic effects by scientists at TDRl and other institutions, which prompted the study of mycotoxins as a specialized field of scientific activity (Coker, 1979).

While the use of Aluminosilicate is spreading around the feed industry at worldwide level as toxin and moisture sorbent, there is a growing concern about the possibility that the product may also adsorb some nutrients contained into feed.

An in vitro comparative assay has been carried out at The Anaerobes Unit of the Pasteur Institute in Paris, in order to study the growth of five strains of Bifidobacterium, in a synthetic culture medium, under the following conditions.

Evaluation of the bio-activity of THEPAX by the assay method routinely used as quality control of the product.

According to Council Directive 93/5/EEC "on the assistance to the Commission and co-operation by the Member States in the scientific examination of questions relating to food" Member States of the European Union can co-operate on problems facing the Commission in the area of food.

According to Council Directive 93/5/EEC "on the assistance to the Commission and cooperation by the Member States in the scientific examination of questions relating to food" Member States of the European Union can cooperate on problems facing the Commission in the area of food. Directive 93/5/EEC also indicates that an inventory of Tasks to be undertaken has to be published as a Commission Decision at least every six months. For each Task, the participating Member States, the Member State which provides coordination and time limit for completion will be indicated.

This trial is an extension of the initial study which evaluates the dispersion and recovery of Monendox 200 BMP® within one single batch. Ten samples were taken during packing from a single batch of feed containing Monendox 200 BMP® at a target level of 60ppm. The samples were submitted to Symbio Alliance in Queensland for independent analysis. Assays were determined by LCMS and were conducted blind. It is concluded that the BMP® processed product is a significantly more reliable form of administering the active ingredient into the stockfeed than a traditional granular or powdered premix. The dispersion and recovery are both predictable and within approved tolerances.

Monensin sodium in powdered or compacted granular form has been known for poor distribution and loss of activity in the production of stockfeed. Further, the cross contamination of following non medicated batches has proven problematic for this active when using compacted granules or powdered product, with unacceptably high readings even after the 5th flushing batch. The aim of the trial was to determine the mixing efficiency, recovery and to evaluate to potential for cross contamination of the following batch, using monensin sodium in Bi Modally Protected (BMP) form. Twenty batches of commercial broiler feed were prepared under normal commercial production conditions. Samples were taken from all 20 batches. Ten samples of non medicated feed were taken from batches immediately following the production of feed containing Monendox 200 BMP. These samples were analysed for monensin sodium levels to determine the potential for carry over or cross contamination of the BMP treated active into non medicated feeds.

An evaluation of the problems facing the micro ingredient industry with comparisons between compacted granules, powders and the novel BMP approach. Areas covered in this discussion paper relate to competition, technology, availability of raw materials, effects of climate and legislative requirements

Manganese (Mn) exposure is one of the main problems in the field of Occupational Medicine in China. In this paper, we investigated cardiovascular, neuroendocrine and neurobehavioral parameters with the aim of studying subclinical effects in Mn-exposed workers in Taiyuan (Shanxi Province, China).

No abstract available.

Cell wall carbohydrates desired for organic feed are derived from the yeast of Saccharomyces cerevisiae. Commonly known as bakers yeast. Cell wall carbohydrates are used as a dietary toxin binder, primarily focusing on the mycotoxins commonly founding fungus that grows in areas of moisture such as stockfeed and grains. Includes a US FDA report on the safety of use for these dietary products

Cell wall carbohydrates desired for organic feed are derived from the yeast of Saccharomyces cerevisiae. Commonly known as bakers yeast. Cell wall carbohydrates are used as a dietary toxin binder, primarily focusing on the mycotoxins commonly founding fungus that grows in areas of moisture such as stockfeed and grains.

Dectin-1 is a mammalian cell surface receptor for (1-3) ß-D-glucans. These are commonly present on fungal cell walls, it has been suggested that dectin 1 is important for recognizing fungal invasion. In this study we tried to deduce the amino acid residues for dectin 1, responsible for ß-glucan recognition. HEK293 cells transfected with mouse dectin 1 cDNA could bind to a gel forming (1-3)- ß-D-glucanschizophyllan.

Coacervation is a term borrowed from colloid chemistry to describe the basic process of capsule wall formation. The encapsulation process was discovered and developed by Barrett K Green of the National Cash Register Corporation (NCR) in the 1940's and 1950's. Actually, coacervative encapsulation (or microencapsulation) is a three part process: particle or droplet formation; coacervative wall formation; and, capsule isolation. Each step involves a distinct technology in the area of physical chemistry. The first coacervative capsules were made using gelatin as a wall in an "oil- in-water " system. Later developments produced "water-in-oil" systems for highly polar and water soluble cores. The capabilities and limitations of coacervative encapsulation are presented along with the basic literature references. There is some discussion on the art of coacervation.

The BMP process was designed following detailed investigations into technological problems with animal feed additives. Namely: Dust emissions, Cross contaminating characteristics, Mixing problems.

96 piglets were divided into 2 groups and penned in the same building in pairs. The same basal diet was supplied supplemented with 50mg/kg Carbadox for half of the pigs and 1g/kg THEPAX for the remainder. Before feeding the test diets, the piglets were allowed to acclimatise to trial conditions for 15 days.

Following an initial analysis of the origin and the nature of dust in the animal feed industry, the possible risks to those handling animal feed were analysed. Trials were carried out in 17 plants in 5 Italian regions in order to evaluate environmental dust quantitatively (Total Dust and Respirable Fraction) qualitatively (by choosing suitable "tracers" from the most hazardous substances used in the feed industry). The results obtained from the monitoring exercises were compared to fixed security limits. The trials were made whilst the factories were using a new type of nutritional / zootechnical premix in which dust emission is kept under control. The results obtained show that the fixed security limits for safe working were not exceeded. It is concluded that the premix technology in question offers a viable approach to handling hazardous nutritional and zootechnical substances without recourse to specialized safety equipment.

The present study has been carried out in order to investigate the ability of the product called CAPTEX T-2 (based on modified sodium calcium aluminosilicates, enriched with glucomannas and enzymes) to reduce the effects of aflatoxins, in day-old broiler chicks.

An experiment was conducted to evaluate the effects of different levels of probiotic Thepax® (0.05, 0.1 and 0.15 %) and yeast (Saccharomyces cerevisiae) (0.05, 0.1 and 0.15 %) on performance and egg quality of laying hens. Two hundred and ten 63 wk of age Hy-line W-36 hens were used. The birds were assigned seven treatment groups in a randomized complete block design, with three replicates each with ten hens. The hens performance and egg parameters were evaluated on the three 28-d periods. The results of body weight changes, feed intake, feed conversion ratio, egg production, egg weight, shell percent and albumin weight did not indicate any treatment effect (P>0.05). Shell weight, shell thickness, yolk weight and yolk cholesterol were significantly (P=0.05) different among treatment groups. Yolk cholesterol was lower for 3, 5, 6 and 7th treatments compared to the control. The use of probiotic and Saccharomyces cerevisiae were not affected by production. But, egg quality did improved from 63 to 75 weeks of age.

The effect of live and inactivated yeast, on ruminal fermentation, metabolic parameters and performance has been investigated in many animal species, but mechanisms are still not perfectly clear (Guedes et. al., 2007; Chaucheyras-Durand and Fonty, 2002; Robinson, 2002; Piva et al., 1993). This study was meant to compare the activity of a live yeast and an inactivated yeast on ruminal pH and redox potential (Eh) of sheep fed a high-grain diet.

Effect of dietary yeast culture on milk production and composition, ruminal fermentation, blood parameters, and milk manufacturing properties of 24 mid lactation Holstein-Friesian cows was determined in a 6-wk experiment. The control diet (DM) consisted of 30% corn silage, 22% alfalfa hay, and 48% concentrate. After a 2-wk preliminary period, cows were assigned in equal numbers to either 0 or 10 g/d of yeast culture for the remainder of the 4-wk study on the basis of age, DIM, and pre-trial milk production. Production of milk (26.2 vs. 25.4 kg/d), FCM (23.6 vs. 21.6 kg/d), and milk fat (.90 vs. .78 kgld) was increased significantly by dietary yeast culture. No differences were significant for milk composition. Molar proportion of acetate and acetate:propionate ratio in ruminal liquor tended to be higher in cows fed yeast culture. Total VFA concentration in ruminal fluid was not different between treatments. Manufacturing properties of milk and blood plasma components were not affected adversely by added dietary yeast culture.

This study was conducted to determine the effects of supplementing an inactivated yeast culture 5 (YC) on milk production of mid-lactation Holstein-Friesian cows. Prior to the trial, 2 in vitro 6 experiments showed that the addition of inactivated yeast culture to rumen fluid enhance the 7 production of microbial ATP and the degradability of crude protein and NDF of the diet. Cows fed 8 the supplemented diet improved feed efficiency and milk production, but dry matter intake and milk composition were unaffected.

An occupational health and safety evaluation by Norfeed (UK) Limited

No Abstract available this is a summary of the trial only.

The concept of capability range fits into a specific opinion about quality assurance, and the way that quality control data should be used

The EU has confirmed the phasing out of all antimicrobial / antibiotic feed additives. The necessity has arisen to locate alternative substances (non antimicrobial products) which will offer similar or improved results in terms of animal health and disease control and which will conform to the new guidelines for the safe production of food for human consumption. This EU trial was established by a group of Spanish broiler integrators in conjunction with the Spanish division of the Nutreco milling group (Nanta) and Dox-al Iberica, Spain, encompassing 57 broiler farms with in excess of 1 million birds. The stock feed was produced by the same manufacturer for the entire trial.

Document has been prepared with financial support from the Commission of the European Communities, specific RTD program in the Agriculture and Fisheries FAIR-CT98-4094, a concerted action called 'Quality control measures in the production and processing chain to reduce Fusarium mycotoxin contamination of food and feed grains.

In this study we investigate the effect of ß-glucan derived from Saccharomyces cerevisiae on fungicidal activity, cytokine production and natural killer ativity. Speen and peritoneal cells from female C57BL4/6 mice, previously injected (24 or 48 hours) with 20 or 100 µg of glucan by IP route were assayed. In vivo ß-glucan administration prime spleen cells for a higher production of IL:12 and TNF:a, when S.aureus was used as a stimulous

Recent and current research has provided a wealth of new evidence that demonstrates the importance of the role played by the gut microflora in maintaining the health of domestic animals (Hentges, 1992; Salminen et al. 1993 & 1995). Real and well documented benefits in production and performance have been achieved by veterinary practitioners, farmers, producers and breeders through the manipulation of gut microflora in a wide range of commercially important livestock. These include ruminants (Vanbelle et al., 1990; Kmet et al. 1993; Jouany, 1994; Wallace, 1994), pigs (Jonsson and Conway, 1992; Stewart and Chesson, 1993), rabbits (Hollister et al., 1990), chickens (Barrow, 1992; Wood, 1992), and carnivores (Kishan et al. 1991; Jorgensen, 1991). A test has been designed to verify whether the continuous administration of THEPAX ( a product manufactured by Dox-al Italia spa, consisting of inactivated but intact cells of Saccharomyces cerevisiae Elypsoideus strain) to chickens periodically treated with systemic and non-systemic antibiotics, is able to maintain the gut flora at physiological levels.

Atmospheric levels of manganese (Mn) have significantly increased in urban cities since its introduction as a fuel additive. Recent studies indicate that people with compromised liver function may be at considerably greater risk than the normal population to the toxic actions of Mn. Mn is a potent neurotoxin, capable of producing a variety of neurological symptoms characterized by severe extrapyramidal dysfunction resembling the dystonic movements associated with Parkinson's disease. With the realization of increased environmental exposure to Mn, it has become necessary to delineate the fundamental biochemical and molecular mechanisms responsible for its selective neurotoxic actions to prevent and identify individuals with Mn toxicity.

Yeast and yeast cultures have been fed to ruminants for more than 60 years. The first studies on the use of Saccharomyces cerevisiae in dairy cattle and beef diets began in the decade between years 1940 and 1950. Since then, a huge amount of research on live and dead yeast has been done, but mechanisms to explain their role in ruminant nutrition is still poorly known. To be effective, yeast cultures fed to ruminants should have some characteristics, such as a high concentration per head per day (more than 1 billion UFC) and to be stable in rumen. It has been suggested that the yeast cultures are able to grow in the rumen, at least for a short period of time,; to do that, yeasts should use the trace amounts of dissolved oxygen thereby stimulating growth of rumen bacteria, to which oxygen is toxic. However, for Van Soest (1994) and other authors, yeasts are not able to live in the rumen due to the lack of oxygen; the ideal range for the development of Saccharomyces cerevisiae is between pH 4.3 and 4.6, while at pH 6.5 (average pH of rumen environment), their reproduction is markedly reduced (Piva et al., 1989). Under these pH conditions, the Saccharomyces cerevisiae cell slows down its reproductive activity, but reacts to the adverse conditions by producing a greater quantity of nucleotides, amino acids and vitamins, together with a very large quantity of enzymes that contribute to autolytic effect on its cell wall.

Why powdered feed additive are uncontrollable in feed

A discussion on the behaviour of medicinal and therapeutic stockfeed additives

Mycotoxicoses occur as a result of consumption of feed contaminated with the toxic metabolites and fungi (Table 1). Over 200 mycotoxins have been described, but in poultry and swine, aflatoxicosis, ochratoxicosis and fusariotoxicoses are most commonly encountered. Mycotoxic fungi are responsible for significant financial losses encompassing a broad spectrum of crop and animal agriculture and extending through the food chain to the consumer. Crop farmers are impacted by the field-borne, intermediate and storage fungi. Contamination of successive stages in the growing cycle and subsequently during the storage result in destruction and downgrading of grains and peanut meal as well as depressing nutritional value. Mycotoxins lower the profitability of animal production through decreased growth, feed conversion efficiency, liveability and reproductive potential. Mycotoxin residues are responsible for the destruction of contaminated milk and dairy products. Farmers are obliged to spend money and resources on programs to detect and ameliorate fungal metabolites in ingredients, rations and in the production environment (2). Producers and consumers in the rural areas and tropical countries are especially vulnerable to acute toxicity and to the long term mutagenic and immunosuppressive effects of mycotoxins which excerbate primary infections or interact with intercurrent diseases.

The adsorption of aflatoxin B1 (AFB1) by cation-exchanged clinoptilolite zeolitic tuff and montmorillonite was investigated at 37 ºC and pH 3.8 from an aqueous electrolyte having a composition similar to that of gastric juices of animals. Both minerals were exchanged from the natural form to the sodium form and then to the Cu 2+ ,Zn 2+ and Co 2+ -rich forms. The cation exchange was different for the different cations, but in all cases the exchanges were larger on montmorillonite than on clinoptilolite. The degree of exchange on montmorillonite was 76 % for copper (from a total of CEC 0.95 meq/g, Cu 2+-0.73 meq/g) and 85 % for zinc and cobalt. Under the same conditions (concentration, temperature, pH, contact time), the degree of exchange on zeolitic tuff was 12 % for Cu 2+ (from a total CEC of 1.46 meq/g, Cu 2+ -0.17 meq/g), 8 % for Zn 2+ and 10 % for Co 2+ Both groups of mineral adsorbents showed high AFB1 chemisorption indexes (c?). For the montmorillonite forms, c? ranged from 0.75 for the Cu-exchanged montmorillonite to 0.89 for the natural Ca-form, 0.90 for the Zn-exchanged form and 0.93 for the Co-exchanged montmorillonite. The adsorption of AFB1 on the different exchanged forms of clinoptilolite gave similar values of c? for the Cu and Ca forms (0.90) and values of 0.94 and 0.95 for the Zn- and Co-exchanged form. The impact of the mineral adsorbents on the reduction of essential nutrients present in animal feed (Cu, Zn, Mn and Co) showed that the Ca-rich montmorillonite had a higher capability for the reduction of the microelements than the Ca-rich clinoptilolite.

Toxic metabolic by-products of fungi, known as mycotoxins, have received considerable attention during the past several years. Mycotoxins are known to cause serious health problems in animals including equine leukoencephalomalacia in horses and porcine edema in swine. Reduced weight gain, capillary fragility, reduced fertility, suppressed disease resistance, and even death have been attributed to mycotoxins. No animal is known to be resistant, but in general, older animals are more tolerant than younger animals. Some mycotoxins, fumonisin, aflatoxin, and ochratoxin in particular; have also been associated with human health problems. Certain mycotoxins are suspected carcinogens. The mycotoxins reported to occur in corn are listed in table 1. The most commonly found mycotoxins in North Carolina-grown corn are aflatoxin, fumonisin, and deoxynivalenol (DON). Probably the most familiar of these is aflatoxin. The detection of aflatoxin in corn can result in a reduced price for grain or even rejection. A mycotoxin of more recent concern is fumonisin. Some corn containing greater than 15 parts per million (ppm) fumonisin was rejected in North Carolina in 1998. Contamination of corn with mycotoxins is greatly influenced by weather.

The use of organic acids as a possible replacement for chemical growth promotants (antibiotics at low dosage, administered continuously into the feed).

Key observations: No difference in weight evolution was found between supplementation with Avilamycin as growth promoter and Thepax – Thepax provides weight gain comparable to a growth promoter.

Doxal research team undertook work to look at the stabilising effects during adaptation to concentrate diets of the Yeast (Saccharomyces Cerevisiae strain Elypsoideus – THEPAX©) on the rumen microflora in vivo using fistulated sheep. Both groups (two sheep per group) were given the same dietary regime: the initial diet contained 90% hay and 10% soybean meal; the barley content was increased weekly at the expense of the hay in the diet from 20 to 66% barley inclusion. One group received in addition 10mg of THEPAX per ml rumen fluid each day before the morning meal.

The assay method, of biological nature, is aimed to ascertain the Bioactivity Index of THEPAX, considered as the capacity to stimulate the growth of a strain of Lactobacillus acidophilus. The product THEPAX is a dry extract of whole cells of Saccharomyces cerevisiae, obtained from a specific strain, known for its high bio-activity. The principle of the assay for the bio-activity determination is based on nephelometry evaluation of the growth of Lactobacillus acidophilus, at various time from the inoculum, with or without THEPAX presence as pre-biotic, and compared to other yeasts. The difference between the growth with or without THEPAX, as well as the other yeasts, allows to extrapolate the bio-activity index.

At weaning, eight groups of pigs were selected (as pairs) from a batch of 80 piglets and divided so that each pair of groups contained the same number of piglets of similar weight. One group received standard diets containing Avilamycin at 44mg/kg (from Maxus) whilst the remaining group received an identical diet containing Theaponin to provide 250mg/kg THEPAX and 25g/kg Norponin (Nor-Feed ApS standardised extract of Yucca schidigera).

Sixteen one tonne batches of pig grower feed were prepared under normal commercial production conditions. Eight batches included a powdered oxytetracycline hydrochloride premix (OTC) based on a maize starch diluent. The remaining eight batches included a product processed using the patented bi-modal protection (BMP) micro-granulation technology. Ten samples were taken from the finished feeds of each medication type and submitted to the Australian Government Analytical Laboratories for determination of OTC content. OTC assays were by HPLC and were conducted blind. The powdered premix gave lower recoveries of OTC at assay than did the BMP processed product. These differences proved significant at p ¡ü 0.005. There was no significant difference between standard deviations of assays obtained for each medication type (p ¡ü 0.05). It is concluded that the BMP processed product is a significantly more reliable form of OTC administration than is the traditional powder premix. possible reasons for this are discussed as are some of the factors which may affect assay results in this type of trial.

Extensive work has been done on oral immunostimulation. Glucans and other compounds have been tried at laboratory scale with encouraging results and in the field with limited results. More consistent results are obtained with nutriceuticals, nutrients that are required by the immuno system for the development of its functions. Surprisingly, nucleotides have been, almost completely, overlooked. A literature review on their use in humans, other mammals, poultry and fish have brought to light some remarkable information that reveals that nucleotides are semi-essential nutrients that can become critical under certain conditions. A profile of nucleotides content of Thepax is reported.

So far, premixes, supplements and concentrates, containing micro and macro elements such as vitamins, minerals and amino acids have been prepared by the simple dilution of the active ingredients into a suitable carrier of vegetable or mineral origin.

The Role of Lactic acid Bacteria - Scientific evidence The use of growth promoters in animal feeds, new trends and developments THEPAX - Rationale of its Effects on Monogastric animals Thepax, the Synbiotic feed additive Organic acids vs prebiotics Commercial Trial to Investigate the Benefits of Thepax on a Commercial Pig Unit With a poor Health Record

A herd of 220 Holstein cows calved in four batches per year were fed Thepax at the rate of 25g/h/d in addition to their standard feed program. Pasture and fodder allocations were kept constant across the data collection period before during and after the treatment period.

This trail was conducted to assess the affect of Thepax® in a pasture based dairy production system typical of those found on the east coast. The herd used for the trial, has a rolling herd average of 7500l/c, has individual feed allocation based on days in milk (DIM) and on farm milk volume recording. The intention was to test if Thepax® can elicit a measureable improvement in production in a commercial production system.

Extract of the Paper published in the Journal of Poultry Science / Scientific Works of Poultry Research Production, State enterprise in Ivenk, Slovakia, Journal 25, 1990.

A balanced formulation containing Inactivated Dry Extracts of Selected Yeast strains, Oligofructoses and High Performance Inulins, in a free flowing blend to be mixed into finished feeds, for monogastrics.

The possibility that the BMP process may improve in-feed stability of feed additives has been explored in a small-scale trial with Ampicillin trihydrate premixes.

A risk assessment

A risk assessment

A risk assessment

A risk assessment

A risk assessment

A risk assessment

A risk assessment

A risk assessment

A risk assessment

A risk assessment

The addition of Clays, Aluminosilicates and Zeolites to finished feed has become almost a routine procedure in Europe, in the aim to limit the presence of mycotoxins and, therefore, reduce their negative effects in live organisms.

A risk assessment

To determine the benefits of using Thepax inactivated yeast in the production of fattening lambs. Results in terms of weight gain, feed conversion ratios and fattening scores will be evaluated.

This study was conducted to determine the effects of supplementing an inactivated yeast culture 5 (YC) on milk production of mid-lactation Holstein-Friesian cows. Prior to the trial, 2 in vitro 6 experiments showed that the addition of inactivated yeast culture to rumen fluid enhance the 7 production of microbial ATP and the degradability of crude protein and NDF of the diet. Cows fed 8 the supplemented diet improved feed efficiency and milk production, but dry matter intake and milk composition were unaffected.

Yeast products are widely utilized as feed additives for ruminant animals in many parts of the world. While the number of yeast products that have undergone substantive evaluation in controlled research studies is somewhat limited, there is a widespread belief among dairy and beef producers, and ruminant nutritionists, that yeast products are beneficial by enhancing dry matter (DM) intake and overall animal performance. Mechanisms have been proposed to explain why yeast products could stimulate DM intake and productivity in growing and lactating cattle. Perhaps the oldest hypothesis is that the yeasts are able to grow, at least for a short period of time, in the rumen thereby directly enhancing fibre digestion and/or producing nutrients that stimulate growth of rumen bacteria, which do the bulk of the fibre digestion.

Emerging evidence suggest critical roles for APC's is suppressing immune responses. Here, we show tha zymosan, a stimulus TLR2 and dectin 1, regulates cytokine secretion in DC's and macrophages to introduce immunological tolerance. First zymosan induces DCs to secrete abundant IL,10 but little IL,6 and IL, 12. Indusction of the activation protein1 (AP,1) transcription factor c,Fos. Such DC's stimulate antigen: specific CD4+ T cells poorly due to IL:10 and the lack of IL:6…