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In general apparent ileal digestibility values of amino acids are lower than apparent faecal digestibility values (Just, 1980) and since nitrogen entering the large intestine may not be utilised by the pig (Zebrowska, 1973) apparent ileal digestibility values should offer a better estimation of the nutritive value of dietary protein. However, for this to be confirmed it must be demonstrated that such values when used in diet formulation are more accurate predictors of pig performance. Therefore, a trial was conducted to examine whether the detrimental effect of heat treated fish meal on pig performance could be reduced by formulating diets based upon either apparent faecal or ileal amino acid digestibility values.

Copra meal is a by-product of the coconut oil industry and is a potential source of protein and energy in the diets of pigs and poultry in the tropics. However, previous studies with pigs have suggested that its use may be limited because of poor growth performance associated with levels of inclusion above 300 g/kg (Creswell and Brooks, 1971). The experiment reported here and conducted under tropical conditions at the University of the Philippines at Los Banos was designed to study possible ways of feeding copra meal at levels of inclusion greater than 300 g/kg in the diets of pigs while maintaining acceptable animal performance.

Inconsistencies in the estimated phosphorus requirements of growing pigs have come to light in recent years due to environmental constraints being imposed on the livestock production sector. Values of a net requirement estimated by the ARC (1981) extend from 4.6 g/day for 25kg liveweight to 5.2 g/day for 45kg pigs, but current literature suggesting that the actual requirement may be lower (eg Jongbloed and Everts, 1991) calls for a revision of previous recommendations.Around two thirds of the total phosphorus in cereals exists in the form of insoluble phytates which must be degraded before the phosphorus can be absorbed in the intestine. Under experimental conditions, the use of phytase in pig diets has demonstrated consistent improvements in phosphorus digestibility. The enzyme hydrolyses phytate by stepwise removal of orthophosphates, which become available for absorption in the gut. Although quantification of phytase/phosphorus substitution is as yet undetermined, digestibility results so far indicate that if used correctly the enzyme could largely replace inorganic phosphates, particularly in regions where soil phosphate levels are of concern.

The dietary phosphorus requirement of young pigs is not well established. Values of a net requirement estimated by the ARC (1981) extend from 2.7 g/day for 5kg pigs to 4.6 g/day for 25kg pigs but current literature suggests that the actual requirement may be lower than this. Although maximum bone mineralization is not necessary for optimum growth, later bone development should not be impaired by a deficiency of phosphorus.Use of phytase in piglet diets has resulted in increased rate and efficiency of gain (Beers and Jongbloed,1992) and increased metatarsal phosphorus (Young et al, 1993). The enzyme hydrolyzes phytate, releasing phosphorus into the gut, and could thus be used in place of expensive inorganic phosphates. Quantification of phytase/phosphorus substitution is as yet undetermined. Therefore this experiment was conducted to look at the phosphorus requirement for growth and bone development and to assess the effect of phytase on dietary phosphorus requirement.

Enzymic hydrolysis of phytates has been shown to improve the apparent digestibility of phosphorus. Other nutrients bound to phytates may be released during phytate degradation by phytases. Dietary yeast may also improve the availability of phosphorus to pigs by altering gut fermentation patterns.The objectives of this experiment were (1) to study the effects of phytase on the apparent digestibility of phosphorus and other nutrients associated with phytates, and (2) to determine whether an alteration in fermentation induced by dietary yeast inclusion influenced availability of phosphorus.

The fatty add profile of pig fat has profound effects upon both the eating and keeping quality of pig meat. Fatty adds within carcass fat may arise from two discrete sources, being de novo synthesis and direct deposition from fatty acids present In the diet. The relative contribution of these two routes, together with the fatty acid profile of dietary fat, will Influence the chemical composition of carcass fat. It is well established that diets containing high levels of unsaturated fatty acids will result in softer and oilier carcass fat and It Is often considered inappropriate to feed such diets during the finishing phase of pig growth. However the speed with which carcass fat reflects a change in dietary fat has not been quantified. The objective of the current trial was to measure the rate of change in fatty acid profile of carcass fat of finishing pigs following major changes in dietary fat.

The development and improvement in processing technology in recent times has resulted in considerable reduction in trypsin inhibitors and enhancement of protein quality of full-fat soyabeans (FFSB) thus leading to their increased use in relation to soyabean meal (SBM) in animal diets. This study was designed to provide information on the relative nutritive values of the various soya products for their effective use in diet formulation.

Tannins are phenolic compounds which possess antinutritional properties. Studies to assess the effects of tannins have either used bean cultivars containing differing levels of tannins (Jansman, Huisman and van der Poel, 1989) or tannin extracts (Marquardt, Ward, Campbell and Cransfield, 1977). This experiment evaluated the effect of tannins on the utilization of dietary energy and nitrogen by broiler chicks using two lines of field beans which were isogenic except for tannin content. Chicks were used because of their sensitivity to nutritional changes in the diet.

One of the disadvantages in using field beans (Vicia faba) has been the presence of tannins which form insoluble complexes with proteins, enzymes and carbohydrates. This experiment evaluated zero-tannin, white-flowered varieties and tannin-containing, coloured-flowered ones, in terms of the utilization of energy and nitrogen by broiler chicks.A basal diet was designed to give sub-optimal levels of protein (70% of requirement, ARC 1975). The 5 bean varieties were incorporated into the basal diet at 4 rates (Table 1). Three of these were white-flowered with negligible levels of tannin (Albinette, 0.006g/kg; Blandine, 0.005g/kg; and Albatross, 0.010g/kg) and two were coloured-flowered and contained significant levels of tannins (Minden, 0.138g/kg; and Alfred, 0.113g/kg). Methionine and lysine were subsequently added in quantities sufficient to ensure they were not first limiting. The 16 diets were fed to Cobb broiler cocks of 7 days initial age (4 replicates of 2 birds per cage).

The development of a feeding regime to ensure optimum sow productivity must be based on well-founded principles of nutrition. This paper examines both the short-term and long-term nutritional requirements for a number of features of sow productivity. The specific effects of nutrition during puberty, pregnancy and lactation and the interrelationship between the various stages of the reproductive cycle are discussed. Many of the decisions regarding the development of a feeding strategy, including the predicted effect to a change in feed intake, can then be seen in the light of these interactions.

Thirty-four Landrace × (Landrace × Large White) gilts were randomly allocated at a mean age of 70 days to one of three treatments. The treatments involved gilts being relocated and housed adjacent to a mature boar (their first boar contact) in addition to having full contact with a boar for 30 min each day at a mean age of 160, 180 or 200 days. The gilts were served twice at the pubertal oestrus and the reproductive tracts were examined at slaughter 21 days later to determine ovulation rate and embryo survival. Delaying the application of a puberty stimulus beyond a mean gilt age of 160 days resulted in gilts being significantly (P

The literature on the effects of nutrition during the growing period and the oestrous cycle on the reproductive performance of the pig is reviewed. It is concluded that the age at which the gilt reaches puberty is influenced much less by nutrition than by other environmental factors. This being so it would be advisable to feed the gilt at a level of intake which optimises food conversion efficiency. By extrapolation from the recent work of Davies and Lucas (1972) this might be expected to occur when dietary energy intake was approximately three times the maintenance requirement. In some circumstances ovulation may be a limiting factor to litter size therefore in order to maximise ovulation rate it would be advisable to feed gilts ad libitum for 11–14 days before the oestrus at which they are to be mated. Following mating the feed intake of the gilt should be reduced to provide an intake of approximately 5 Mcal ME/day. On the limited evidence available at present it would appear likely that reducing the age at which gilts reach puberty and are mated will produce small reductions in litter size, but that such a practice may be justifiable in terms of savings in food consumption. From the evidence that is available it would appear that nutritional variations during the weaning to remating period and the post weaning oestrous period may influence ovulation rate. However, ovulation rate does not seem to be the factor which limits litter size. Post weaning nutrition may be of significance in determining if and when the female returns to oestrus and also in influencing conception rate. There is certainly a case for feeding the primiparous sow liberally between weaning from her litter and conception. However in the older sow the effects are less clearly defined. The precise requirements of the sow between weaning and conception still await definition.

Catabolism of the sows’ maternal body tissues which commonly occurs during lactation starts not at parturition but during the latter part of the preceding pregnancy. An experiment was conducted to study the response of sows to the same amount of feed distributed differently between pregnancy and lactation.Two patterns of feed distribution taking account of the anabolic/catabolic change in late pregnancy were compared with a conventional system which makes the major change in feed level at parturition.

In certain parts of the world the use of grain crops for animal feeding is limited and where there is competition for direct human use, alternative feeds must be considered. Root crops are a potential feedstuff for growing pigs in some situations and the objective of the present programme of work is to establish the nutritional value of these materials and to investigate factors which effect their utilisation in pig diets.The high moisture content of root crops results in low nutrient density and the current experiment was designed to examine whether this resulted in any limitation on food intake and subsequent growth performance of growing pigs. This was achieved by formulating diets to contain different proportions of root crop and concentrate; these diets were isoenergetic/isonitrogenous when based on dry matter but varied in nutrient density when expressed on a fresh weight basis.

A trial was conducted to measure the voluntary feed intake of pigs drawn from two genetic sources when fed diets of different digestible energy concentrations. The genetic sources were Large White x Landrace commercial hybrids (CH) and Landrace (Landrace x Large White) pigs from the Sutton Bonington herd (SB). Two sexes were used (boars and gilts) and four diets were formulated with energy densities of 8.6, 10.7, 12.9 and 15 MJ DE/kg feed. All nutrients were adjusted to maintain a constant ratio with energy. Pigs were offered these diets ad libitum from 25 - 55kg liveweight in individual pens. After slaughter, backfat and eye muscle measurements were taken and hams dissected into component tissues. Meat quality was also evaluated : pH of ham and loin were taken at 45 minutes and 24 hours post mortem. The ‘Grau Hamm Paper Press’ method was used to evaluate water holding capacity. Depth of colour was determined by reflectance spectrophotometry.

Coconut meal is a by-product of oil extraction from dried coconut kernel or copra. It is a highly variable material which, in practice, may contain from almost 0% ether extract (EE) when the oil has been solvent extracted to around 20% EE when the least efficient mechanical extraction methods are used. The trial reported here examined the effect of processing which produced meals of varying levels of residual oil, on subsequent dietary energy values.Five coconut meals (A-E) and one sample of unprocessed copra (F) were used as a basis of the dietary treatments. Sample A was a solvent extracted meal and samples B-E were all extracted by mechanical means. Analysis of the samples is shown in Table 1.

Indigestible markers are important in the determination of digestibility values when only a sample of the material may be collected. This situation arises when collecting ileal digesta for determination of ileal digestibilities via a T-piece cannula. Consequently a comparison of indigestible markers was undertaken.The trial consisted of five treatments: (a) 0.1% Cr2O3, (b) 0.5% Cr2O3, (c) 0.1% TiO2, (d) 0.5% TiO2 and (e) no external marker. Treatment (e) was used for the determination of lignin. 5 cannulated (Landrace x Large White) x Landrace gilts, initially weighing an average of 35 kg, were arranged in a 5 x 5 Latin square. They were placed in metabolism crates, for the collection periods, and housed in a building with a controlled environment. Each of the five periods was preceded by a 9 day acclimatization period. Before period 1 faecal samples had been taken from the 5th to the 9th day after external markers had been included in the diets. These samples were used to determine the quantity of marker excreted in relation to time after inclusion in the diet. Each period consisted of a 5 day marker-to-marker collection of faeces and collection of ileal digesta on the 1st, 3rd and 5th day after the faecal collection. Ileal digesta was collected every 2 hours for 12 hours. Pooled samples of ileal digesta and faeces for each period were used for the determination of nitrogen digestibility.

In addition to acting as a source of the amino acid itself, methionine can act as a source of methyl groups. The requirement for sulphur amino acids is therefore influenced by the inclusion level of alternative methyl donors in the diet e.g. choline. An initial experiment was designed to ensure an adequate supply of choline so that in subsequent studies the need for methionine per se could be established. Blood metabolites were used to study the requirements. Three diets with different levels of methionine plus cystine (3.5, 4.5 and 5.5 g/kg) were formulated and randomly assigned to 36 pigs. To a basal diet, containing 660 mg/kg choline, choline chloride was added producing diets with choline levels of 660, 860, 1060, 1260, 1460 and 1660 mg/kg. The pigs were randomly allocated three levels of choline, each for a period of three days; this ensured that each treatment was repeated six times. Blood samples were taken by jugular venepuncture 4 hours after feeding at the end of each 3 day period and repeated at 3 liveweights (35, 55 and 75 kg). Blood parameters (urea and plasma amino acids) were used to measure the response.