Protein nutrition, through altered amino-acid supply, regulates the quality and quantity of animal products, and deficiencies in supply of / response to amino-acids may be a limiting factor in ruminant efficiency. The effects of amino-acid supply may be indirect, via modulation of anabolic hormonal signalling. In particular, amino-acid limitation reduces insulin-like growth factor-1 (IGF-1) - and increases IGF-1 binding protein 1 (IGFBP-1) - production by the liver, and hence modulates the sensitivity of tissues to pituitary GH as an anabolic signal (Gluckman et al, 1987). The mechanisms through which amino-acids exert these selective effects on liver protein production are not understood.

The present study sought to determine whether the effects of amino-acids on total cellular protein synthesis are sufficient to account for observed reductions in IGF-1 production in cultured ovine hepatocytes. In addition the use of two dimensional polyacrylamide gel electrophoresis (2D-PAGE) to visualise changes in translation of individual proteins caused by amino-acids in cultured ovine hepatocytes is described.

Although insulin has been shown to stimulate muscle protein accretion in nonruminants (e.g., Wray-Cahen et al., 1998) evidence for this same effect in ruminants has been equivocal (e.g., Oddy et al., 1987; Wolff et al., 1989). Moreover, when insulin has been reported to have an anabolic effect in ruminants, the animal has been in the fasted state. In addition, Garlick and Grant (1988) have shown that branched-chain amino acids (BCAA) enhanced insulin-stimulated protein synthesis in fasted rats. The primary aim of the present study was to ascertain whether insulin increases phenylalanine (Phe) uptake (used as an index of skeletal muscle protein anabolism) across the hind limb of fed lambs. A secondary aim was to determine if infusion of BCAA, alone or in combination with insulin, would stimulate Phe uptake greater than insulin alone.

Lean tissue deposition occurs in ruminants fed at maintainance energy intake provided that sufficient protein is supplied in the diet (Fattet et al 1984). The effect may be at least partially regulated by the endocrine system as circulating levels of insulin and insulin-like growth factor-1(IGF-1) are increased by the inclusion of high levels of protein in energy restricted diets (Kriel et al, 1992). The present study examines the extent to which IGF-1 and insulin concentrations are modulated by the inclusion of various amounts of rumen protected protein (Amino Green 98) in lambs restricted in metabolisable energy (ME) intake.

A crucial factor in the prevention of hypothermia in the neonatal lamb is the functional activitation of a mitochondrial uncoupling protein (UCP1) in brown adipose tissue. UCP1 disappears from lamb brown fat over the first 14 days of life (Finn et al., 1998), but it is not known whether this process can be modulated in lambs by the release of catecholamines which have been established in rodents as a mediator of the response to cold stress. This study examines the effect of administering a β-adrenoceptor agonist on the disappearance of UCP1 and UCP1 mRNA during early neonatal life, using immunohistochemistry and in situ hybridization.

Thermal processing is carried out on commercial diets primarily to kill bacteria and reduce mould growth, although additional benefits have been shown such as an inactivation of trypsin inhibitors present in soyabean meal (McNaughton and Reece, 1980). However, heat treatment if too severe can produce negative effects, such as reduced apparent digestibility and increased viscosity of gut contents in broilers, an effect reversed by the addition of enzymes (McCracken et al, 1993). The aim of this study was to examine the effect of heat treatment during diet preparation on ileal and overall apparent digestibility of diets for growing pigs, made from two wheat varieties of different in vitro viscosity (8.8 vs 20.8 cps) with and without the addition of feed enzyme.

Lewis et al (1998) observed differences in overall and ileal apparent digestibility of wheat varieties using a wheat / casein diet but no significant relationships with in vitro viscosity of wheat. In the present study six of the varieties used previously were selected to examine if the variety differences would be repeatable using a more commercial diet and the extent of correlation between overall digestibility (OD) and performance parameters. The wheats chosen were Abbott, Caxton, Crofter, Encore, Hussar, Riband (in vitro viscosity range 6.8 - 19.2 cps). Three contained the 1B1R gene (Crofter, Encore, Hussar) and three were soft wheats (Crofter, Encore, Riband). All wheats were harvested in Northern Ireland in 1997.

There is considerable literature on phosphorus requirements of pigs and on the use of phytase to improve phosphorus digestibility and reduce P excretion. However, much of this has been concentrated on weaned pigs (eg Beers and Jongbloed, 1992), the finishing stage (eg Russo et al, 1995) or the diets used were synthetic (eg Ketaren et al, 1993). The available P requirement for pigs between 20-50 kg was estimated at 3 g/kg by ARC (1981) but the NRC (1998) estimate is 2.3 g/kg. This paper reports digestibility and P utilisation data on 40 kg pigs using the grower diets employed in a study on the impact of commercially feasible reductions in dietary P content and of phytase inclusion on growth and bone strength (Weatherup et al, 1999).

Recommended P concentrations in pig diets have been reduced recently (NRC, 1998) but few studies have evaluated these throughout both the growing and finishing stages (Harper et al., 1997). These new recommended P concentrations were based on feed intakes of 1.8 and 2.8 kg/d for growers and finishers respectively which are much higher than the feed intakes of 1.4 and 2.1 kg/d currently achieved in normal UK commercial practice. This suggests that dietary P concentrations should be increased from NRC (1998) estimates to approximately 6 g/kg to ensure adequate growth performance and structural soundness of UK pigs. Phytase enzyme has also been shown to improve the bioavailability of dietary P (Harper et al., 1997). This experiment was designed to examine the effects of grower/finisher diet P concentration and presence of phytase on growth performance and finisher bone thickness and strength.

The use of exogenous enzymes extracted from batch microbes has expanded recently; and different enzymatic additives are being used to improve the nutritive value of monogastric diets. Most legume seeds contain measurable amounts of ? -galactosides, such as raffinose and stachyose (Kuo et al., 1988). These oligosacharides have been proved to pass undigested through the small intestine, and depress to some extent the digestibility of other nutrients (Gdala et al, 1997). Our aim was to assess the effect of adding a high dose ? -galactosidase to cereal-soybeanpea based diets on performance and digestive efficiency of growing pigs.

54 growing pigs (LW 43 ± 2 kg) were randomly allocated in eighteen pens, three animals each, and fed “ad libitum” a basal diet either supplemented with ? -galactosidase (Biogalactosidase, Quest; 400 ppm) or unsupplemented (nine pens/treatment).

It is well documented that grower and finisher pigs do not utilise raw soyabean protein well (Crenshaw and Danielson 1985), whereas processed soyabean meals contain high quality protein that is well digested by the pig (true ileal lysine digestibility 86% - NRC 1998). Laboratory studies showed significant (p<0.001) increases in in vitro nitrogen digestibility of raw soyabean meal (RSB) and micronized soyabean meal (MSB) after protease treatment (Beal et al.1998). Indicating that there is potential for improving the nutritional value of these protein sources with exogenous proteases. The objective of this study was to determine if these increases were reflected in the pig.

Nutritional studies with pigs have most commonly used chromic oxide as an inert marker, (Low, 1982) although there are various problems associated with its use. Continued experimentation to validate the use of other substances as inert markers has led to titanium dioxide becoming more popular. In an evaluation of markers using a single dietary treatment, (Jagger et al. 1992) it was concluded that titanium dioxide at a rate of 1g/kg feed was the most suitable marker of those tested. More recent work using ten dietary treatments, (Thompson and Wiseman, 1998) found titanium dioxide to be a valid inert marker in the determination of energy digestibility of diets which varied in content of fat and fibre. The objective of the current experiment was to evaluate titanium dioxide as a marker in the determination of digestibility of components in diets based on a range of raw materials.

The use of lactic acid bacteria in pig feeds for the control of coliform pathogens in the intestine is now common. These “probiotic” preparations do not persist in the intestine, and must therefore be added daily. Previous work (Reid and Hillman, in press) has indicated that the proportion of Lactobacillus spp. to coliform bacteria can be affected by the type of starch included in the diet, which may provide a more cost-effective means of controlling coliform pathogens. However, the previous study found the greatest enhancement of Lactobacillus spp with waxy maize, one of the most expensive starches. Consequently, this study sets out to determine whether an enhancement of this proportion could be obtained with a more economical starch, or with mixtures of starches.

Plasma protein is known to increase feed intake and growth rate in the first week following weaning (Coffey and Cromwell, 1995) although these benefits are not always evident some weeks later (Nessmith, et al., 1997). However, as most UK food retailers demand the exclusion of same species animal products from livestock diets, plasma products are excluded from UK piglet diets even though they are commonly used in several EU countries. The benefits of plasma protein are thought to result from its immunoglobulin content therefore alternative sources of specific immunoglobulins may be equally beneficial. One such source is egg protein derived from hens which have been vaccinated against specific pig pathogens (Kichura, 1997) eg Protimax (DuCoa, USA). The aims of this experiment were to estimate the potential loss of efficiency in the UK by the exclusion of porcine plasma protein from weaner diets and to determine whether egg protein containing specific immunoglubulins could produce similar piglet performance to plasma protein.

Previous experiments (Sinclair et al., 1998) have indicated that reproductive function in lean modern genotypes may be more dependent on body protein mass than, as previously believed, on body lipid reserves. Related work (Sinclair et al., 1996) also indicated that lean genotypes of sows are particularly sensitive to dietary protein restriction during lactation. This experiment was designed to achieve differential body reserves of protein and fat at farrowing by different feeding strategies during pregnancy, and to measure the interactive effect of dietary protein during lactation on subsequent nutrient partitioning.

A 3x2 factorial experiment involving 60 first parity sows compared 3 different pregnancy feeding strategies and 2 lactation diets. During pregnancy, sows were fed, from day 42, either a set quantity (mean of 2.27 kg/day) of basal diet (5g lysine/kg, 13 MJ DE/kg [C]), or basal diet + energy (maize starch + soya oil in 3:1 ratio [E]), or additional basal diet supplying both protein and energy [P].

Selection for efficiency of lean growth has lead to a marked reduction in fat gain and voluntary food intake (VFI) of modern genotypes. There is concern that future improvements in lean growth rate may be limited by appetite. Moreover, the ability of lean genotypes to adjust their VFI in response to variations in nutrient density is not well known. Such genotypes may fail to compensate their intake in response to marginal reductions in nutrient density, which could affect growth performance. The aim was to evaluate the VFI and growth performance of ‘White’ and Meishan cross growing pigs in response to incremental reductions in dietary energy content.

The problem of seasonal infertility in pigs has been recognised for many years. The infertility complex can may be manifested by increased returns to service, prolonged weaning to oestrus intervals and decreased litter size. The purpose of this trial was to evaluate the effects of Buserelin treatment on fertility in sows and gilts during the seasonally infertile period.

A total of 1231 mixed parity sows and gilts from five outdoor herds in East Anglia were randomly assigned to one of three treatment groups. Any sows not presented for service at first post weaning oestrus were excluded. All sows and gilts judged to be in adequate health and condition to be kept in a commercial breeding herd were included. Group C sows and gilts were given no treatment. Group R1 sows and gilts were injected i.m. with 8μg Buserelin (2.0ml Receptal; Hoechst Roussel Vet UK Ltd) on the day of service.

N-alkanes are components of plant cuticular wax which have been successfully used as markers for the estimation of grass intake and digestibility in grazing ruminants (Dove and Mayes, 1991). Natural n-alkanes are predominately odd chain, and a known dose of an artificial even chain n-alkane (normally c32 or c36) is used to enable intake to be measured. Dietary n-alkanes may behave differently in the gastro-intestinal tract of ruminants and non-ruminants (Mayes et al, 1995). Therefore, in order to utilise this methodology in studies of outdoor pigs, this experiment was carried out to validate the faecal recovery of n-alkanes in this species. Since n-alkanes are soluble in lipid, which is often incorporated at high inclusion levels in pig diets, the experiment was also designed to determine whether n-alkane recovery is influenced by dietary lipid content.

The ‘standard’ human approach test has been used extensively since the early 1980's to assess fear responses in most farmed species. However, in recent years, there has been considerable debate questioning its efficacy given the short duration of the familiarisation period and the suitability of the location of the testing environment, i.e. the home pen versus a novel arena (Pedersen, 1997). It is possible that the test simply reflects an animal's level of motivation to explore the novel arena and any novel objects therein rather than a specific response to the presence of a human. This work addresses both the length of acclimatisation period and the location of the test arena.

There has been considerable concern over the welfare of sows housed in farrowing crates due to the severe restriction of movement this imposes upon them. A number of alternative systems have therefore been developed which allow sows greater freedom of movement. The aim of this study was to compare the behaviour and performance of sows housed in conventional crates with sows housed in a group-house Thorstensson system.

A total of 18 Large White x Landrace sows were farrowed in crates or a group-housing Thorstensson system (balanced for parity and time of year). Two batches of seven were farrowed through the Thorstensson system of which five in each batch were selected for the current analysis (based on ease of observation). Thus a total of ten sows were analysed from the group-system (mean parity: 1.90 ± 0.40; 6 gilts). In addition eight sows were analysed from crates (mean parity 1.62 ± 0.26; 4 gilts).

Injectable solutions of iron are a long established and widely accepted method of preventing anaemia in neonate piglets, although recently several oral iron preparations have become available which avoid the intrusive nature of injection. However, both methods of iron administration involve handling piglets which in itself may be stressful to the neonatal piglet. The aim of this study was to investigate the heart rate and behavioural responses of piglets during handling, or during handling associated with administration of either oral or injectable iron.

Whole litters of 33 PIC Camborough sows were randomly assigned to one of three treatments, each administered before 24 hours of age; injection of 1ml of iron into the neck muscle (Gleptosil; Alstoe Animal Health), oral administration of 2ml of iron (Neoglobin; Labtec) and handling the piglet for 30 seconds between removal and replacement in the creep, but without the administration of iron.