Metabolizable Research Articles

Evaluation of energy systems in determining the energy cost of gain of growing-finishing pigs fed diets containing different levels of dietary fat

Two experiments were conducted to evaluate the impact of different energy systems in predicting the energy cost of gain of growing-finishing pigs fed diets containing different levels of dietary fat. The diets in both experiments were based on wheat, corn and soybean meal and supplemented with 0, 1.75, 3.50 and 5.25% tallow. In Experiment 1, 24 crossbred barrows (Duroc×Landrace×Yorkshire) were randomly allocated to one of the four dietary treatments to determine the digestible (DE) and metabolizable (ME) energy content of the diets and net energy (NE) was calculated from DE and ME values. In Experiment 2, 96 crossbred barrows (Duroc×Landrace×Yorkshire) were used to evaluate the effectiveness of the energy systems in predicting the energy cost of gain for growing-finishing pigs fed ad libitum. There were six pens per treatment and four pigs per pen. The results obtained in trial 1 were used for calculating the energy cost of gain in trial 2. During the growing period, there was a linear decrease (p < 0.05) in the DE and ME cost of gain, while the NE cost of gain was not influenced by level of fat. During the finishing period, neither DE, ME or NE cost of gain were influenced by the dietary fat level. For the total experiment, the DE and ME cost of gain decreased (linear effect; p = 0.001), but there was no significant decrease in the NE cost of gain. It is concluded that the NE system can predict the performance of growing-finishing pigs more precisely for diets differing in fat content than can the DE and ME systems.

Amino acid digestibility and energy content of two different soy hull sources for swine (2007)

This trial was conducted to determine and compare the digestibility of amino acids and energy of soy hulls from two different sources. Five growing barrows (initially 150 lb) fitted with T-cannulas were each fed three different diets in a crossover design. Each of the first two diets contained 66.7% soy hulls from two different sources (Soy hulls A and Soy Hulls B). The third experimental diet was N-free and based on corn starch and sucrose for determining basal endogenous amino acid (AA) losses. Ileal digesta and fecal samples were collected during each period and analyzed for amino acid and energy contents. Due to poor flowability of digesta through the Tcannula of one pig when fed diets containing soy hulls, it was removed from the experiment and thus, only four pigs were used in all data analyses. Apparent (AID) and standardized (SID) ileal digestibilites, and gross (GE), digestible (DE), metabolizable (ME), and estimated net (NE) energy values were then calculated from these analyses. Both samples were analyzed for particle size using Ro-Tap shaker with a stack of Tyler screens. Particle size of soy hulls A and soy hulls B were 619 and 691μ, respectively. The results of the trial showed differences in nutrient composition and in amino acid and energy digestibilities between the two soy hulls. Apparent ileal digestibility values of lysine, methionine, and threonine in soy hulls A were 58.38, 65.93, and 50.68%, respectively and 51.10, 57.51, and 37.54%, respectively in soy hulls B. Standardized ileal digestibility values of the same amino acids were 61.13, 69.53, and 62.25%, respectively for soy hulls A and 54.60, 62.32, and 51.96%, respectively for soy Hulls B. As a percentage of CP, standardized ileal digestible lysine, methionine, and threonine values were 4.09, 0.83, and 2.16% for soy hulls A; and 4.01, 0.85, and 2.01% for soy hulls B, respectively. The ME, DE, and estimated NE values were 1,037; 1,097; and 722 kcal/lb for soy hulls A and 989, 1,030, and 680 kcal/lb for soy hulls B, respectively.

Availability, fermentability, and energy value of resistant maltodextrin: modeling of short-term indirect calorimetric measurements in healthy adults

Determination of the metabolizable (ME) and net metabolizable (NME) energy of total carbohydrate requires estimation of its available (AC) and fermentable (FC) carbohydrate content. Modeling of indirect calorimetric observations (respiratory gas exchange) and breath hydrogen would appear to make it possible to estimate noninvasively these nutritional quantities and the approximate time-course of availability. We assessed the time-course of metabolism and energy availability from resistant maltodextrin (RMD) by modeling of respiratory gases after a single oral dose. Seventeen healthy adults (13 M, 4 F; aged 25-46 y) were randomly assigned to treatments (water, maltodextrin, or RMD) in a multiple-crossover, single-blinded trial with > or = 7 d washout. We monitored 8-h nitrogen-corrected oxygen and carbon dioxide exchanges and breath hydrogen. All treatment groups took low-carbohydrate meals at 3 and 6 h. Indirect calorimetry alone provided only qualitative information about the nutritional values of carbohydrate. In contrast, modeling of gaseous exchanges along with the use of central assumptions showed that 17 +/- 2% of RMD was AC and 40 +/- 4% was FC. As compared with 17 kJ gross energy/g RMD, mean (+/- SE) energy values were 7.3 +/- 0.6 kJ ME/g and 6.3 +/- 0.5 kJ NME/g. The fiber fraction of RMD provided 5.2 +/- 0.7 kJ ME/g and 4.1 +/- 0.6 kJ NME/g. Modeling with the use of this noninvasive and widely available respiratory gas-monitoring technique yields nutritional values for carbohydrate that are supported by enzymatic, microbial, and animal studies and human fecal collection studies. Improvement in this approach is likely and testable across laboratories.

The combined effects of animal species (sheepversuscattle) and level of feeding on digestible and metabolizable energy concentrations in grass-based diets of cattle

AbstractA total of 317 dairy and beef cattle, offered grass silage-based diets, have been subjected to energy metabolism measurements in calorimetric chambers in 11 feeding experiments at this Institute. In addition the silages (no. = 33) were also given individually to sheep as a sole food at maintenance feeding level for measurement of energy intake and outputs (faeces and urine). The digestible (DE) and metabolizable (ME) energy concentrations of mixed diets for sheep at maintenance were estimated using these measured silage data, predicted silage methane energy output and tabulated energy values of concentrates. The objective of the present study was to use treatment mean data (no. = 59), derived from the cattle (production level) (MEprod or DEprod) and the sheep (maintenance level) (MEmaint or DEmaint), to evaluate the combined effects of animal species and level of feeding on dietary ME or DE concentration. The mean-square prediction error technique and the sensitivity test both indicated that there was little bias derived from the deviation of the slope (line bias) when relating MEprod (DEprod) with cattle to MEmaint (DEmaint) with sheep. Relating feeding level to the decline in ME or DE concentration (from maintenance to production level) revealed that the constant had no significant effect on the relationship, suggesting that there was little difference in dietary ME or DE concentration between sheep and cattle when given food at maintenance. ME d and DE d were significantly related to MEmaint and DEmaint (P &lt; 0001) respectively. These two relationships were however influenced (P &lt; 0001) by level of feeding above maintenance (FL-1). There was little effect of silage DM proportion in the total diets (S/T) on the depression of ME concentration from maintenance to production levels, while this effect on the depression of DE concentration was significant (P &lt; 0001). Therefore, the following two equations are recommended to calculate MEprod and DEprod concentrations respectively for cattle using data obtained with sheep at maintenance. Alternatively, with each unit increase in feeding level above maintenance, dietary ME and DE concentrations respectively were reduced by proportionately 0016 and 0025 for grass silage-based diets, irrespective of the effect of forage proportion on the latter. MEprod = [1 068 - 0019 ✕ (FL-1)] ✕ MEmaint - 0·755 DE d = [0·891 + (-0027 + 0018 ✕ S/T) ✕ (FL-1)] ✕ DEmaint + 1·355

Estimativas da produção de leite por vacas holandesas mestiças, segundo o sistema CNCPS, em dietas contendo cana-de-açúcar com diferentes valores nutritivos

O objetivo do presente estudo foi usar os dados observados sobre as variações nos teores da fibra em detergente neutro (FDN), lignina e das frações de carboidratos e das correspondentes taxas de degradação de 15 variedades de cana-de-açúcar, para avaliar a disponibilidade destes nutrientes em promover produção de leite de vacas holandesas mestiças, usando o sistema CNCPS. Um suplemento nutricional composto de silagem de milho, caroço de algodão, farelo de soja e uréia foi usado para complementar as exigências nutricionais destes animais na produção de 10 kg de leite diário. Os valores utilizados para predizer as respostas na produção de leite foram: FDN (%MS) -- 40, 50 e 60, lignina (%FDN) 10,14 e 18, taxas de digestão (%/h) dos carboidratos não fibrosos (CNF) -- 10,20 e 30 e taxa de digestão (%/h) dos carboidratos fibrosos (CF) -- 1, 2,5 e 4. A cana-de-açúcar, quando usada como principal volumoso da dieta, acarretou redução na ingestão de matéria seca e energia, limitando a produção de leite destes animais. A predição da quantidade de leite que poderia ser produzida em função da quantidade de energia metabolizável (EM), fornecida pela dieta, decresceu 24%, quando o teor de FDN aumentou de 40 para 60%, para um percentual de 14% de lignina. Também houve acréscimo de 14% na produção de leite, quando a taxa de digestão dos CF aumentou de 1 para 2,5%/h. Embora as variações nos teores de FDN e lignina e nas taxas de digestão dos carboidratos, das variedades de cana-de-açúcar, tenham promovido grande efeito sobre a produção de leite das vacas mestiças, torna-se necessária a validação destes resultados.

Energy and nutrient use of palm kernels, palm kernel meal and palm kernel oil in diets for growing pigs

A metabolism experiment was conducted with 13 gilts over four periods to investigate the effects of age or weight of pigs, level of inclusion and methods of estimation of apparent digestible (DE) and metabolizable (ME) energy and nutrient digestibility of full-fat palm kernels (FFPK), recombined palm kernel oil and meal (OPKM) and palm kernel oil (PKO). Each palm kernel product was evaluated at levels equivalent to added oil of 40, 80 and 120 g kg −1 in a basal diet. Extracted palm kernel meal (PKM) was also evaluated in the basal diet at the same level as in OPKM. Thus, 13 treatments arranged in four blocks (time periods) constituted the experimental data analysed using a randomised complete block design. Digestible energy and ME contents and apparent digestibility of nitrogen (ADN), dry matter (ADD) and oil (AOD - employing two oil analytical methods) of palm kernel products were estimated by single level assay and by regression with the latter yielding DE values of 40.2, 19.5, 22.1 and 13.1 MJ/kg DM for PKO, FFPK, OPKM and PKM, respectively. The corresponding values for AOD were 1.08, 0.93, 1.03 and 0.88. While the level of inclusion and pig weight (over the range 40–76 kg) did not significantly affect dietary energy and nutrient digestibility of palm kernel products, the form of oil inclusion had considerable effect with OPKM being better utilized than FFPK. Digestibility of oil in the palm kernel products measured by the ether extract (EE) method was, in general, significantly higher than that estimated by the acid ether extract (AEE) procedure. The results suggest the necessity for digestibility coefficients of oils and fats in oil bearing ingredients to be re-evaluated in the light of the currently applied analytical method as figures obtained using the traditional ether extract method may not be applicable to the true nutritional value of feed ingredients and consequently may lead to imprecise diet formulation.

Determinação dos valores de energia e do balanço de nitrogênio de alguns alimentos para leitões na fase inicial

Este trabalho foi realizado para obter valores de energia digestível (ED) e metabolizável (EM) de quatorze alimentos, em cinco experimentos, utilizando-se 144 leitões com 28 dias de idade e peso médio de 9,42±0,76 kg. O teor de energia digestível (ED) e o de energia metabolizável (EM) foram determinados por intermédio do método de coleta total de fezes e urina. As fontes de proteína provenientes do leite foram superiores aos subprodutos da soja, com relação à digestibilidade da energia e da proteína. Entre os subprodutos da soja, a proteína concentrada e a proteína texturizada apresentaram os maiores valores de digestibilidade da energia e a soja integral extrusada, os menores. A digestibilidade da matéria seca e da energia do milho e do farelo de soja com 46,5% de proteína bruta foi semelhante à observada em avaliações com suínos adultos, indicando que a capacidade dos leitões jovens para digerir estes dois alimentos foi semelhante à dos suínos adultos. Houve redução da relação EM/ED, em virtude do aumento do teor de proteína e do desequilíbrio entre os aminoácidos da dieta e diminuição da relação entre energia bruta e N excretados na urina, com aumento do teor de proteína da dieta e vice-versa. Estes dados indicam a necessidade de se desenvolverem fatores de correção para EM específicos para diferentes grupos de alimentos e condições de experimentação.

Effect of cultivar and fungicide treatment on the yield and nutritive value of winter and spring oat grains grown in England and Wales, 1989–91

The effect of a comprehensive (three-spray) fungicide programme on yield, specific weight (SW), 1000-grain weight (TGW), nutritive value and yield of both winter and spring oat grains was investigated over a 3-year period (1989–91). With winter oats, four cultivars (Aintree, Image or Pennal, Solva and Kynon), were tested at each of three sites (Gwent, Hereford and Kent). Similarly for spring oats, four cultivars (Dula, Keeper, Rollo and Rhiannon) were tested at each of three sites (Cornwall, North Yorkshire and Wales).On winter oats, fungicide treatment produced a significant increase (P&lt;0·05) in grain yield, but did not on spring oats. Fungicide treatment produced no significant effect on SW, TGW or nutritive value of the winter or spring oats. With winter oats, but not with spring oats, fungicide treatment produced a significant increase (P&lt;0·05) in the yield of digestible (DE) and metabolizable (ME) energy for pigs and ruminants respectively.The naked oats, Kynon and Rhiannon, had a significantly lower yield, higher SW and lower TGW than the other conventional cultivars (P&lt;0·05). Their oil, fatty acid, protein, DE and ME contents were also significantly higher than the other cultivars (P&lt;0·05). Nevertheless, the yield of protein, DE and ME tended to be less from naked oats than from some of the other cultivars tested.On winter oats, TGW, protein content and protein yield, dry matter (DM) and fatty acid content and on spring oats, yield, TGW, ME yield, DM, oil, fatty acid, protein, DE and ME all varied between years. With winter oats, oil content and energy values were negatively correlated with yield and positively correlated with SW. With spring oats, DE and ME were positively correlated with SW. It was concluded that, on winter oats, fungicide treatment was worthwhile in terms of grain yield, but this was not the case for spring oats. Also with winter oats, but not spring oats, fungicides gave useful increases in the yield of energy. The naked oats, Kynon and Rhiannon, had a distinct advantage in terms of nutritive value, but their low yield compared with the conventional cultivars tended to negate this benefit.

COMPOSICION QUIMICA Y DIGESTIBILIDAD IN VIVO DE ENSILAJE DE BALLICA ITALIANA (L. multiflorum Lam., cv. Concord) EN CUATRO ESTADOS FENOLOGICOS

The purpose of this study was to evaluate the effect of the phenological stage at harvesting on the chemical composition and in vivo digestibility of dry matter (DMD) and both digestible (DE) and metabolizable (ME) energy content of silage made from a sward of Italian ryegrass (Lolium multiflorum, cv. Concord). Grass was harvested at four stages: pre-inflorescence emergence, early spike emergence, early flowering (anthesis) and milky grain. Four male calves of ca. 200 kg liveweight were used in sequential metabolic trials, with intake restricted to 70% of ad. lib. and with total collection of faeces and urine. Fresh grass and silages were analysed for dry matter (DM), crude protein (CP), neutral detergent fibre (NDF), acid detergent fibre (ADF) and ME estimated in vitro. As fresh grass matured, its DM concentration increased from 13.6 to 29.5%, NDF from 50.8 to 60.9% and ADF from 30.6 to 39.5%. CP and ME were reduced from 13.4 to 7.8% and from 2.44 to 2.19 Mcal/kg DM, respectively. The resulting silage increased DM (from 14.4 to 25.2%, oven basis) and decreased CP (from 12.9 to 9.1%). NDF varied from 58.7 to 63.3% and ADF from 39.3 to 41.1 %. Both fibre fractions failed to exhibit a consisten! trend with maturity. ME estimated in vitro changed from 2.25 to 2.16 Mca/kg DM. In vivo DMD decreased as growing period of pasture increased, from 65.4 to 54.2%. Same trend was found for DE which decreased from 2.91 to 2.31 Mcal/ kg DM (oven basis) and for ME which declined from 2.23 to 1.82 Mcal/kg DM (oven basis). Both DE and ME presented higher values (ca. 0.3 Mcal/kg DM) when expressed on a toluene DM basis. ME/DE ratio was slighty lower in an earlier (0.78) compared to a later (0.81) growth stage. It is concluded that silage harvesting should not exceed the spike emergence stage.

Prediction of the feeding value of maize silages by chemical parameters, in vitro digestibility and NIRS

Fifty maize silages with known in vivo organic matter digestibility (VOMD) were used to compare the potential of chemical parameters (dry matter (DM), crude protein (CP), crude fibre (CF), crude fat (Cfat), ash, neutral detergent fibre (NDF), acid detergent fibre (ADF), acid detergent lignin (ADL), starch (STA), in vitro digestibility (with rumen fluid (RFOMD) or commercial cellulases (COMD)) and NIRS (monochromator: 1100–2500 nm) in predicting VOMD and calculated metabolizable (ME) and net energy lactation (NEL). A second series of 51 maize silages with digestibility and energy value based on RFOMD served as test set. Further, the possibilities of NIRS to predict chemical composition and calculated protein value (DVE and OEB) were investigated. NIRS-equations, developed by partial least squares analysis, were tested by internal and external validation. The correlation with VOMD was highest for COMD ( r = 0.82), followed by RFOMD (0.81), ADF (−0.77) and NIRS-predicted VOMD (0.75). ADL could explain some supplemental variance in VOMD besides ADF and RFOMD, but not with COMD. Multiple linear regressions to predict ME and NEL, irrespective of being based on chemical parameters, RFOMD or COMD had similar residual standard deviations of about 0.21 and 0.16 MJ kg −1 DM, respectively. With NIRS the standard error of prediction amounted to 0.28 and 0.20 MJ kg −1 DM, respectively. The relative ability of NIRS to predict chemical composition was very good for residual moisture, STA, ADF, NDF and CP, moderate for CF and ADL and low for ash. The prediction potential for OEB was moderate and nihil for the little varying DVE-content.

Effect of body weight on net energy value of feeds for growing pigs.

Digestible (DE), metabolizable (ME), and net (NE) energy values of seven diets were measured in castrated male pigs of 45 (Stage 1), 100 (Stage 2), or 150 (Stage 3) kg BW. Diets were prepared from a basal diet supplemented with cornstarch, or sucrose, or a protein mixture (referred to here as protein), or rapeseed oil, or a mixture of fibrous ingredients (referred to as fiber), or rapeseed oil+fiber. Diets were fed at similar levels (x maintenance) at the three stages. Heat production at different feeding levels, as measured by indirect calorimetry, allowed calculation of energy retained by each pig (equal to ME intake minus heat production) and an estimate of fasting heat production of all pigs (360 kcal/kg BW.42). Net energy intake was then calculated for each pig as retained energy plus 360 x BW.42. The amounts of DE digested before the end of the ileum (DEi) and in the hindgut (DEh) were measured. Formulation of diets allowed calculation of energy values of the ingredients added to the basal diet. Digestibility and metabolizability of diets increased significantly from Stages 1 to 3, with higher variations for low-energy diets. The NE:ME ratio (k, %) and dietary NE content were not affected (P > .05) by stage of growth. On average, k was 75%, with higher values for diets containing rapeseed oil or starch (77%) and lower estimates for the fiber diet (72%). As a consequence, k was approximately 90, 82, 80, 72, and 60% for rapeseed oil, cornstarch, sucrose, protein, and fiber, respectively. These values are consistent with the lower k value for ME from DEh (57 vs 78% for DEi). Present data confirm that the hierarchy between feeds is dependent on the energy system (DE vs ME vs NE) and that the NE concept is superior in predicting the "true" energy value. The present results combined with previous ones show that, under practical conditions, the same NE prediction equations based on digestible nutrient contents, or preferably DE or ME contents, can be applied at all stages of growth in pigs. However, attention should be paid to factors such as BW or feeding level that affect digestibility and metabolizability of feeds markedly. The effects are the most important for ingredients.

Prediction of net energy value of feeds for growing pigs.

Digestible (DE), metabolizable (ME), and net (NE) energy values of 61 diets were measured in 45-kg growing Large White boars. Net energy was calculated as energy retained at an average ME intake equivalent to 540 kcal/kg BW.60 plus fasting heat production estimated from data of the present experiment as 179 kcal/kg BW.60. Retained energy was measured as the difference between ME intake and heat production obtained in respiration chambers. The amounts of DE digested before the end of the ileum (DEi) and in the hindgut (DEh) were also measured for each diet. Regression equations for predicting dietary NE content from digestible nutrient levels or from DE or ME and chemical characteristics or from chemical composition only were calculated. Efficiencies of utilization of ME for NE (k, %) were also obtained. The mean k value for the 61 diets was 74% (range: 69 to 77). Digestible nutrients were used differently for NE: k values varied from approximately 60% for digestible CP or digestible cell wall fractions to 82% for starch and 90% for digestible ether extract. Accordingly, k for ME associated with DEh was lower than ME from DEi (58 vs 76%). Equations for predicting NE content are proposed. Their applicability, the comparison with other available NE prediction equations, and the effects of energy system on diet formulation are discussed.

Energy evaluation systems for pig diets: a review

Different energy values are given to a given feed according, firstly, to the considered step of energy utilization by the pig (digestible (DE), metabolizable (ME) or net (NE) energy) and, secondly, to the prediction method used for each step. The aspects developed in the first part of this review relate to the effects of chemical composition of the diet and animal factors such as physiological stage or body weight, and also the interactions between diet and animal, on digestive and metabolic utilization of energy. In a second part, the available DE, ME and NE systems when applied to diets or ingredients are presented. In the third part, the different energy systems (firstly DE vs. ME vs. NE, and secondly the NE systems) are compared in terms of advantages, limits and applicability for each of them. The comparison indicates that the hierarchy between diets and, more clearly, between ingredients is markedly dependent on the energy system. The composition of diets (ingredients and chemical characteristics) resulting from least-cost formulation is also affected by the energy system. The last part of the review considers the validity of the different energy systems or their ability to predict pig performance. From this review, it is clear that more emphasis should be given to, firstly, study digestive interactions and, secondly, improve the methods (chemical, physical, in vitro, …) used for (rapid) prediction of energy values of pig feeds.

Digestible and metabolizable energy values of ten feed ingredients in growing pigs fed ad libitum and sows fed at maintenance level; comparative contribution of the hindgut

Digestible (DE) and metabolizable (ME) energy values of 14 diets were measured in three groups of pigs: sows fed at a maintenance level; 45-kg growing pigs fed nearly ad libitum; and ileo-rectal anastomized (IRA) growing pigs. The energy digested in the hindgut was calculated as the difference between DE values in intact growing pigs or sows and DE measured in IRA pigs. Diets were prepared from ten ingredients (wheat, corn starch, soybean meal, rapeseed oil, meat and bone meal, corn gluten feed, wheat bran, wheat middlings, wheat straw and sugar beet pulp), the inclusion levels of ingredients being independent. The DE and ME values of ingredients were calculated by regression of DE or ME values of diets on levels of inclusion of ingredients. The DE values of ingredients were higher in sows than in growing pigs, the difference being greater for high-fibre diets. Apart from wheat straw, which contributed negatively to DE in growing pigs, the largest difference was obtained for sugar beet pulp, for which the DE value in growing pigs represented 60% of the value obtained with sows. No difference was observed for wheat and corn starch. The contribution of the hindgut was higher for sows than for growing pigs and more pronounced for high fibre ingredients (sugar beet pulp, soybean meal). Rapeseed oil was totally digested in the small intestine. Comparison of measured and tabulated DE values shows a good agreement for wheat, corn starch and soybean meal. But tabulated values overestimate the DE values of fibrous ingredients and rapeseed oil for growing pigs and underestimate the DE values of the same ingredients (except rapeseed oil) for sows. Conclusions are equivalent for ME. The consequences of these digestive interactions on the energy evaluation of pig diets are discussed.

Digestible, metabolizable and net energy values of 13 feedstuffs for growing pigs: effect of energy system

Digestible (DE), metabolizable (ME) and net (NE) energy values and digestible nutrient contents of 17 complex diets were measured in 45 kg growing boars. Values for DE and ME were estimated from collection of faeces, urine and measurement of methane production, while NE was obtained from energy balances carried out in respiration chambers. Diets were prepared from 13 ingredients (wheat, barley, maize, tapioca, sweet potatoes, soyabean meal, rapeseed meal, sunflower meal, peas, maize distillers grains, maize gluten feed, cane molasses and animal fat), the inclusion levels of all ingredients being independent. The DE, ME, NE and digestible nutrients contents of ingredients were then calculated by regression of nutritive values of diets on levels of inclusions of ingredients. Digestibility of energy of diets was negatively affected by their neutral detergent fibre (NDF) content (−1.1% per 1% NDF). Digestibility of fat increased curvilinearly with dietary fat content. Energy evaluation systems (DE versus ME versus NE) affected the hierarchy between the tested ingredients: when the energy content of wheat was considered as 100, the energy values of soyabean meal, tapioca and animal fat were 101, 98 and 184 on a DE basis, 97, 99 and 187 on a ME basis and 66, 106 and 241 on a NE basis. The correspondence between measured NE of ingredients and NE values which can be calculated from available NE systems varied according to the system. The study indicates that the tabular DE content or nutrient digestibility coefficients of fibre or fat rich ingredients are overestimated when they are included in complex diets. The results emphasize the necessity for estimating energy values of pig feeds, and especially ingredients, on a NE basis. In addition, more attention should be paid to digestive interactions occurring with changes in feeding level or digestive capacity of the pigs, especially with complex diets.

Predicting the energy value of pig feeds using in vitro or analytical methods

An in vitro method, using ileal digesta or faecal extract as inocula, was used either alone or in combination with chemical composition to predict the content of metabolisable (ME) and digestible energy (DE) of cereals, yellow lupin and rape-seed oilmeal (either singly or in mixed feeds) for pigs. By means of regression analysis, in vitro dry matter solubilisation with ileal digesta (IDMS) and faecal extract (FDMS) as inoculum was found to be correlated to the in vivo ME (IDMS, r 2 = 0.94, cv = 1.13; FDMS, r 2 = 0.67, cv = 2.64 and DE (IDMS, r 2 = 0.90, cv = 1.40; FDMS, r 2 = 0,73, cv = 2.24) content of the feeds, when pure rape-seed oilmeal and yellow lupin were excluded. The correlations were further enhanced by combining IDMS with the starch, crude protein and dietary fibre content in the regression equations (ME, r 2 = 0.98, cv = 0.85; DE, r 2 = 0.97, cv = 0.92). In vivo metabolisable and digestible energy contents could also be predicted from chemical composition, employing either non-nutrients (ash and dietary fibre; ME, r 2 = 0.95, cv = 1.01; DE, r 2 = 0.93, cv = 1.23) or nutrients (starch, crude protein and crude fat; ME, r 2 = 0.93, cv = 1.37; DE, r 2 = 0.91, cv = 1.48). It is suggested that in vitro or appropriate dietary components, i.e. starch, crude protein and dietary fibre, could be employed to predict the nutritive value of feeds for pigs.

The dietary energy values of soya-bean oil, tallow and their blends for growing/finishing pigs

ABSTRACTTwo fats, soya-bean oil and tallow, were blended in the ratios 70: 30, 50: 50 and 30: 70. The ratios of unsaturated to saturated fatty acids (U/S) of the blends were 3·18, 2·08 and 1·49 respectively; values for soya-bean oil and tallow were 6·69 and 0·93. These five fat sources were each included into a basal diet at levels of 40, 80 and 120 g/kg. The digestible (DE) and metabolizable (ME) energy together with the apparent fat digestibility (AFD) of the experimental diets were measured in a metabolism trial based upon four 4 × 4 Latin squares using 16 gilts of 30 kg initial live weight. Linear equations relating dietary DE and ME values to level of inclusion of fat were extrapolated to 1000 g/kg to obtain values for the fats. DE values for soya-bean oil and tallow were 38·06 and 34·16 MJ/kg respectively. Corresponding data for ME were 35·63 and 32·53 respectively. These figures were used to calculate values of the mixtures. Data thus derived did not differ significantly from those determined directly, indicating that there was no synergism between the two fats. DE values of fats determined as the product of AFD of fats and their gross energy followed similar trends. The majority of the increase in values of fats was associated with a change in the U/S ratio from 0·93 to 2·08.

The digestible and metabolizable energy value of copra meals and their prediction from chemical composition

ABSTRACTDigestible (DE) and metabolizable (ME) energy values for five copra meals and a sample of raw copra, with oil contents ranging from 4 to 662 g/kg, were determined with both a high and a low energy basal diet in a metabolism experiment using 16 female pigs. Determined DE values ranged from 12·68 to 29·92 MJ/kg dry matter (DM) and values for ME from 11·95 to 29·08 MJ/kg DM which was a reflexion of their residual oil contents. Regression equations for the six samples were derived with DE and ME as dependent variables and chemical measurements and gross energy as independent variables. The best equation based on a single chemical parameter (ether extract (EE)) was:Improvements associated with including more than one independent variable in the regression analysis were marginal. The most accurate equation (in terms of minimized residual s.d.) based on EE and crude fibre (CF) was:

The digestible and metabolizable energy of two fat blends for growing pigs as influenced by level of inclusion

AbstractTwo fat blends differing in free fatty acid concentration and fatty acid composition were included in cereal-based diets at concentrations of 10, 30, 50, 70, 90 and 110g/kg. The digestible (DE) and metabolizable (ME) energy of each diet were estimated in a metabolism experiment based on three 4 × 4 Latin squares using gilts of 30 kg initial live weight fitted with indwelling bladder catheters. With increasing dietary fat both DE and ME increased linearly (P &lt; 0·001) and the linear equations derived were used to calculate the DE values of the two fats by extrapolation. Values were 26·4 and 24·2 MJ/kg respectively for fats A and B. The change in dietary D E and ME to increasing dietary fat concentration showed a curvilinear trend (P = 0·0987 and 0·1268 respectively for DE and ME ) indicating that fats may not be correctly evaluated at only one rate of inclusion. The quadratic functions derived were interpolated to provide DE and ME data for the two fats. Values for DE for fat A ranged from 32·7 o t 25·7 MJ/kg at 10 and HOg/kg, and for fat B from 38·6 to 26·3 MJ/kg at 10 and 110 g/kg. Data for ME followed similar trends. It was concluded that multi-level assays are important in the evaluation of fats and that the rate of decline of fat DE and ME was specific to the fat examined.

EFFECTS OF CROSSBREEDING AND SEX ON ENERGY REQUIREMENTS AND UTILIZATION BY YOUNG PIGS

The influence of crossbreeding and sex on digestible (DE) and metabolizable (ME) energy values, fasting heat production (FHP), energy requirement for maintenance and growth, and on the efficiency of utilization of metabolizable energy in young weanling pigs, was investigated by employing a comparative slaughter technique. The pigs obtained by insemination of Yorkshire sows with pooled semen (equal number of sperms) from purebred Yorkshire and Hampshire boars, were identified for genotype by blood-group typing. A total of 37 pigs was used in this study, of which 9 pigs selected at random were killed to provide the initial body composition and energy status of pigs in the feeding experiment. The remaining 28 pigs (16 purebred: 8 male and 8 female; and 12 crossbred: 6 male and 6 female) were allotted at random to a feeding experiment of a randomized complete block design involving a 2 × 2 × 2 factorial arrangement (purebred vs. crossbred, male vs. female, and level of dietary energy input: 130 and 330 kcal ME/Wkg0.75 daily). One metabolism trial with each pig individually kept in a crate was conducted during the 4th week of the 40-day feeding period. The coefficients of DE and ME were 89.2 and 84.2%, respectively, and were not influenced by sex or genotype. An interaction was observed in the estimates of the fasting heat production and energy requirement for maintenance. Purebred Yorkshire males had a greater fasting heat production than Hampshire × Yorkshire males, whereas females of the two breeding groups had similar values. The apparent efficiency of utilization of ME was 76% and the net efficiency of utilization of ME available above maintenance was 66%. The energetic efficiency and the net energy value of the diet were similar for both breeding groups and sex. The mechanism of rapid gains due to crossbreeding was investigated.