The presence of high concentrations of sodium in the mammalian small intestine plays a major role in facilitating copper absorption (e.g. Wapnir and Stiel, 1987). An experiment was conducted that investigated the medium and long-term effects of adding sodium to the diet of sheep on the copper accumulation in body tissues.

The level of calcium (Ca) in the diet affects the utilisation of phytic acid-phosphorus (P) through the formation of insoluble Ca phytate and/or reduction of phytase activity (Larsen 1993). High Ca: total P ratios (Ca: tP) (1.5:1 to 2.0:1) in corn-soya bean meal diets supplemented with microbial phytase decreased the utilisation of P for weanling (Lei et al., 1994) and growing-finishing (Liu et al., 1998) pigs. However, it is important to note that the majority of research using supplemental microbial phytase and Ca:P ratios was carried out using maize-soyabean meal based diets. The objective of this experiment is to examine the effect of Ca: tP ratio on the efficacy of microbial phytase and its effects on pig performance, nutrient digestion and mineral metabolism using wheat, barley and soya bean meal based diets.

Numerous studies have clearly shown that the digestibility of phosphorus in pig diets can be improved 20-30% by supplementation with Natuphos® phytase allowing the phosphate content of the feed to be reduced without the P-intake becoming deficient. It is also well accepted that organic acids can significantly improve performance of pigs, particularly up to 30kg liveweight, and recently that synergistic benefits result when both Natuphos® phytase and organic acids are included in the same ration. The objective of this study was to investigate the influence combining Natuphos® phytase (replacing calcium and phosphorus) and organic acids (liquid v dry product) on growing/finishing pig performance.

Concerns over pollution from intensive animal production has lead to developments in enzyme technology to improve the utilisation of minerals such as phosphorous (P) from the diet, and to reduce levels of added inorganic minerals. BASF Natuphos® (registered trademark of Gist-brocades) is a formulation of microbial phytase which improves digestibility of P from plant origin. The aim of this study was to determine whether reducing levels of inorganic P (Dicalcium Phosphate-18%P) and including quantities of Natuphos® would effect have any effect on growth performance and bone strength.

Peptides are intermediates in the conversion of ingested protein to ammonia in the rumen and their accumulation depends upon the nature of diet (Mesgaran & Parker, 1995). Transient accumulation of peptides occurs after feeding and then their concentrations declines. In addition, it suggests that the production of peptides in the rumen was not altered by the protein supplements when diets provided similar effective rumen degradable protein (ERDP)(Mesgaran & Moosavi, 1999). The objective of the present experiment was to investigate the effect of diets, with similar ERDP, containing lucerne hay or silage on the ruminal peptide-N concentrations.

Knowledge of the nutrition of free-ranging herbivores and the impact on their environment is often limited by lack of information concerning the botanical composition of their diets. For herbivores grazing heterogeneous vegetation environments, current methods for estimating the botanical composition of their diets are limited in their scope and accuracy. The purpose of this study was to establish whether urinary metabolites, occurring as a result of ingestion of different individual plant species, have the potential to be used as markers to estimate diet composition.

Unprotected n-3 PUFA supplements fed to ruminants are subject to lipolysis and biohydrogenation in the rumen (Wachira et al. 1998). Improving the n-3 PUFA content of ruminant products therefore requires some form of protection of dietary lipid from microbial activity in the rumen. The in-vitro incubation of PUFA sources offers the opportunity of rapidly determining the level of protection offered against ruminal biohydrogenation. The objectives of the current experiment were therefore to determine the biohydrogenation of a number of sources containing a-linolenic acid using the in-vitro gas production technique.

Ruminants foraging under free-ranging conditions include a diversity of plants in their diet. A wide range of plant secondary compounds are broken down under microbial action in the rumen thus protecting the host animal from their otherwise toxic effects. For example, oxalic acid (OA), found in many tropical grasses, is effectively degraded by Oxalobacter formigenes following a period of adaptation of the rumen micro-flora (Allison et al, 1985). Similarly, butenyl nitrile (BN), a metabolite of glucosinolates, found in brassica plants, has been shown to degrade under rumen microbial action (Duncan & Milne, 1992). The purpose of this experiment was to investigate whether adaptation to the plant secondary compounds found in one food type might influence the degradation of other, unrelated secondary compounds and vice versa.

The effects of fibre level (F) and forage particle size (S) on ruminal fermentation profile is often mediated through changes in feed intake, rates of digestion or passage, ruminal pH and/or bacteria population. Therefore, most in vivo studies have confounded the direct effect of F or S with changes in the rumen environment. In vitro systems allow to control several fermentation conditions independently (pH, flow rates, intake). Total, bacterial and dietary nitrogen (N) flows are generally calculated using liquid associated bacteria (LAB), although solid associated bacteria (SAB) represent about 80% of total bacterial population in the rumen (Olobobokun and Craig, 1988). The objective of this experiment was to study the effects of F and S on microbial fermentation and N metabolism using LAB or SAB values in a dual flow continuos culture system.

In order to provide accurate estimates of protein supply for lactating dairy cows, the effect of feed ingredients on ruminal protein degradability as well as microbial protein synthesis must be determined. The omasal sampling technique coupled with a triple marker method allows the determination of N flow from the reticulorumen with relatively small contribution from endogenous sources (Ahvenjärvi et al., 2000). The objective of the current study was to assess the contribution of microbial and non-microbial fractions to the total flow of N leaving the rumen of lactating dairy cows fed typical feed ingredients.

The efficiency and rate of microbial protein synthesis in the rumen depend on several factors, of which the chemical and physical properties of the plant fibre are among the most important. Estimation of microbial yield and fermentation rate can be obtained from in vitro experiments, which combine gas production and substrate degradability measurements and/or use microbial markers. The aim of this study was to investigate the effect of different fibre sources on microbial protein synthesis in a batch culture system in vitro.

The nitrogen (N) requirements for optimum growth of ruminal micro-organisms are still a matter of controversy. Whereas the results of some experiments indicate that peptides and amino acids stimulate the growth of mixed rumen bacteria in comparison to ammonia, no effect due to the N form has been found in other studies. Therefore, it has been suggested that growth of rumen micro-organisms would be stimulated only when the rate of provision of energy permitted (Cruz Soto et al., 1994). The aim of this study was to investigate the effect of two N sources (ammonia and isolated soyabean protein) on the in vitro fermentation of two substrates (starch and cellulose) differing in their rate of fermentation.

While end-point in vitro techniques provide no information regarding the kinetics of feedstuff degradation they are generally simpler to conduct and require fewer inputs especially with respect to labour. In contrast systems, which permit degradation dynamics to be assessed, require that multiple measurements are made and be continued for a sufficient period to ensure that asymptotic values are reached. This study was therefore conducted to examine the variability that could be expected between short-term end-point in vitro degradability techniques and to compare some of the values with in sacco derived estimates.

Measurement of in situ fungal populations is needed in order to determine the extent of their contribution to the ruminal digestive process. Since chitin is present in the cell wall of rumen fungi (Orpin, 1977), measurement of this polymer can be used to estimate fungal biomass and their growth in vitro (Rezaeian, 1996) and in vivo (Argyle and Douglas, 1989). The objective of this experiment was to study the effect of diet composition on the chitin content of both ruminal fluid and digesta solids as an index of the fungal population in the rumen.

Feeding dairy cows diet formulation by zeolite has been reported improved the efficiency of milk yield (Roussel, 1992). Lupez et al (1992) reported that efficiency of ion exchange in rumen was improved When animals fed with diets containing zeolite. The objective of this study was to determine the effect of zeolite concentration on rumen pH, liquid smell, bacterial flora, protozoa number, methylene blue reduction time and the sedimentation and flotation period.

Commercial proteases yield more reproducible estimates of extent of rumen protein degradation than either in situ or rumen in vitro methods. Although extents of protein digestion determined using commercial proteases have been positively correlated to extents of in situ protein degradation, these values have not proven reliable predictors of rates of rumen protein degradation. This is because no protease-based assay has yet been developed that successfully mimics the specificities of the organisms involved in protein degradation in the rumen. If the proteolytic activity of rumen microbes and commercial proteases can be correctly characterised, then it would be possible to elaborate protease blends that match the protein degradative activity of mixed rumen microbes. The research reported here is an extension of earlier work as a prelude to preparing enzyme mixes with “protease fingerprints” similar to rumen microbes.

Methane production represents an important sink for hydrogen within the rumen Beever (1993) suggested that the partitioning of fermentable dry matter (DM) between microbial synthesis and fermentation products would alter the pattern of hydrogen production and hence methanogenesis. This hypothesis was investigated in vitro using a range of diets varying in carbohydrate source (Moss et al., 2000). Methane production (moles) increased as the proportion of DM fermented to short chain fatty acids (SCFA) increased and this was related to decreasing water soluble carbohydrate (WSC) to cell wall (NDF) ratio of the diet. The objectives of the current study was to design diets with a range of WSC:NDF ratios and to measure the impact on hexose partitioning and methane production in sheep in vivo.

Pig producers are under pressure from cost production and are having to become increasingly environmentally aware. Phase-feeding has been suggested as an alternative feeding strategy, which may have the potential to improve productivity and reduce nitrogen excretion in the growing-finishing period. The objective of this study was to evaluate the effect of mono- versus tri-phase feeding on pig performance and nitrogen balance.

Insulin is a central regulatory factor in the control of nutrient partitioning during growth and development. It has been demonstrated that the rate of protein deposition is elevated in porcine muscle following insulin infusion (WrayCahen 1998), and that the degree of adiposity is positively associated with plasma insulin concentration (Wood et al., 1977; Polonsky 1995). The objective of the study was to examine the effect of plasma glucose and insulin concentrations on growth performance in two porcine genotypes.

A number of antibiotic growth promoters commonly used in EU pig diets have recently been banned following increasing public concern about antibiotic resistance and residues in meat products. Consumer and retail pressure has led to calls for research to identify alternatives to antibiotic growth promoters. It is therefore appropriate to investigate the use of feed ingredients which promote growth and intestinal health for the newly weaned piglet. Piglets which receive diets containing spray dried porcine plasma (SDPP) in the first week after weaning usually show improved feed intakes and growth rates when compared to piglets receiving conventional skim milk based starter diets (Toplis and Miller, 1999). The aim of this experiment was to determine whether similar improvements in piglet performance could be achieved when piglets received a soluble form of SDPP in their water supply instead of in the feed. In addition we investigated whether supplementation of the water supply of piglets already receiving a plasma containing diet further improved their post weaning performance. Although commonly used in Europe SDPP is currently excluded from piglet diets in the UK.