Metabolizability Of Gross Energy Research Articles

Predicting the metabolizable energy and metabolizability of gross energy of conventional feedstuffs for Muscovy duck using in vitro digestion method.

In total, two experiments were conducted to evaluate the effectiveness of an in vitro digestion method for predicting the metabolizable energy (ME) and metabolizability of gross energy (ME/GE) values using in vitro digestible energy (IVDE) and the digestibility of gross energy (IVDE/GE) content, respectively, of conventional feedstuffs for Muscovy ducks. In experiment 1, the apparent metabolizable energy (AME), true metabolizable energy (TME), AME/GE, and TME/GE of eight-grain feedstuff samples (two corn samples, three sorghum samples, and three barley samples) and eight protein feedstuff samples (two soybean meal samples, three cottonseed meal samples, and three rapeseed meal samples) were determined by the tube-feeding method with six different ducks for each sample. In experiment 2, a computer-controlled simulated digestion system (CCSDS) contain simulated digestive fluid was used to determine the enzymatic hydrolysis energy value of feedstuffs, which was defined as IVDE in our study. The simulated gastric fluid containing pepsin and simulated small intestinal fluid containing amylase, trypsin, and chymotrypsin for the in vitro gastric and intestinal digestion, respectively. The IVDE and in vitro digestibility of GE (IVDE/GE) of 16 feedstuff samples were determined using the CCSDS with five replicates per sample. The results showed that the IVDE and IVDE/GE were positively correlated with ME and ME/GE of feedstuffs, respectively. The coefficient of determination of eight regression models in predicting ME (grain feedstuffs: AME = 1.050 × IVDE- 0.9293, TME = 1.032 × IVDE + 0.6478; protein feedstuffs: AME = 1.331 × IVDE- 6.685, TME = 1.269 × IVDE-3.490) and ME/GE (grain feedstuffs: AME/GE = 1.069 × IVDE/GE- 6.516, TME/GE = 1.068 × IVDE/GE + 0.7764; protein feedstuffs: AME/GE = 1.093 × IVDE/GE -19.21, TME/GE = 1.196 × IVDE/GE - 13.25) of feedstuffs for Muscovy ducks ranged from 0.8610 to 0.9921. The accuracy of the regression model was acceptable as the difference between measured and predicted ME and ME/GE values was less than 0.45 MJ/kg (100 kcal/kg) and 2.62% for 14 of the 16 feed samples, respectively. In conclusion, the in vitro digestion method can be used to predict the ME and ME/GE of conventional feedstuffs for Muscovy ducks with acceptable accuracy.

Inclusion of exogenous enzymes to feathers during processing on the digestible energy content of feather meal for adult dogs

This study was conducted to determine the coefficient of total tract apparent digestibility (CTTAD) of nutrients and gross energy (GE), metabolizable energy (ME), coefficient of metabolizability of gross energy (CM of GE), and fecal characteristics of dogs fed diets with two levels of feather meal, with or without addition of an enzyme blend containing lipase and protease activity. Ten adult Beagle dogs (aged between 1 and 2 years and weighing 10.2±1.4 kg) were arranged in a 5 × 3 incomplete Latin square design with five treatments and three periods. The extruded basal diet was provided in equal amounts to all dogs (220 g/d), and 7.5 and 15% of hydrolyzed feather meal without enzymes (HFM) or HFM processed with addition of the enzyme blend (HFM EB) was added on top of the basal diet just before feeding. The contrast analysis showed that inclusion of 7.5 or 15% feather meal negatively affected CTTAD of crude protein (CP), GE, and ME of the diets with no apparent effect of the enzyme treatment. However, when both feather meal samples were evaluated, the HFM EB resulted in better CTTAD of GE and CM of GE (0.774 vs. 0.666) than HFM without enzymes (0.670 vs. 0.567), respectively. There was no effect of either feather meal on fecal score. Regression analysis showed that the enzymes added to the feathers during the digestion process increased digestible energy by 600 kcal/kg of dry matter in the diet containing HFM EB. High-performance liquid chromatography (HPLC) analysis demonstrated that feather meal had a low molecular weight, with about 95% of the molecules below 10,000 Da. Addition of enzymes during the feather hydrolysis process may improve the energy content of the feather meal when included in diets for adult dogs.

Using a computer-controlled simulated digestion system to predict the energetic value of corn for ducks

Two experiments were conducted to develop a computer-controlled digestion system to simulate the digestion process of duck for predicting the concentration of ME and the metabolizability of gross energy (GE) in corn. In a calibration experiment, 30 corn-based calibration samples with a previously published ME concentration in 2008 were used to develop the prediction models for in vivo energetic values. The linear relationships were established between in vivo ME concentration and in vitro digestible energy (IVDE) concentration, and between in vivo metabolizability of GE (ME/GE) and in vitro digestibility of GE (IVDE/GE), respectively. In a validation experiment, 6 sources of corn with previously published ME concentration in 2008 randomly selected from the primary corn-growing regions of China were used to validate the prediction models established in the calibration experiment. The results showed that in calibration samples, the IVDE concentration was positively correlated with the AME (r = 0.9419), AMEn (r = 0.9480), TME (r = 0.9403), and TMEn concentration (r = 0.9473). Similarly, the IVDE/GE was positively correlated with the AME/GE (r = 0.95987), AMEn/GE (r = 0.9641), TME/GE (r = 0.9588), and TMEn/GE (r = 0.9637). The coefficient of determination greater than 0.88 and 0.91, and residual SD less than 45 kcal/kg of DM and 1.01% were observed in the prediction models for ME concentrations and ME/GE, respectively. Twenty-nine out of 30 calibration samples showed differences less than 100 kcal/kg of DM and 2.4% between determined and predicted values for 4 ME (AME, AMEn, TME, and TMEn) and for 4 ME/GE (AME/GE, AMEn/GE, TME/GE, and TMEn/GE), respectively. Using prediction models developed from 30 calibration samples, 6 validation samples further showed differences less than 100 kcal/kg of DM and 2% between determined and predicted values for ME and ME/GE, respectively. Therefore, the computer-controlled simulated digestion system can be used to predict the ME and ME/GE of corn for ducks with acceptable accuracy.

Energy value of wheat dried distillers grains with solubles in roosters, broilers, layers, and turkeys

Four experiments were conducted to measure total tract metabolizability of gross energy (GE), the AME, and AMEn or AME content corrected for a standardized N retention (AMEs) of 10 European wheat dried distillers grains with solubles (DDGS) in roosters, broilers (3 wk old), layers (25 wk old), and growing turkeys (10 wk old). The wheat DDGS were obtained from 7 European ethanol plants and selected to get a large variability in chemical composition. The AME, AMEn, or AMEs of wheat DDGS was obtained according to the difference method. The highest AMEn:GE was obtained for roosters with an average (minimum-maximum) value of 49% (43-55), the lowest in turkeys (43%; 34-50), and intermediate values (47%; 41-57 and 46%; 36-50) in broilers and layers, respectively. Corresponding AMEn values were 10.3 (9.0-11.3), 9.9 (8.5-11.7), 9.6 (7.8-10.5), and 9.6 (7.8-10.5) MJ/kg of DM for roosters, broilers, layers, and turkeys, respectively. The AMEs for N retention equal to 50% of N intake was about 0.6 MJ higher than the corresponding AMEn value. Our data indicate that the AMEn content of wheat DDGS can be predicted from either their acid detergent fiber content (R2=0.79) or the lightness score (L*; R2=0.77) with a common slope but different intercepts for the 4 poultry categories. If dark and overheated samples (L*<50; n=3) with the lowest AMEn:GE ratio and AMEn values are excluded, the average AMEn:GE ratio becomes 51, 49, 48, and 45% in roosters, broilers, layers, and turkeys, respectively, with corresponding AMEn values of 10.7, 10.2, 10.0, and 9.5 MJ/kg of DM that are more representative of a well-controlled process for DDGS preparation. The negative effect of L* on energy value and energy metabolizability indicates that overheating while drying should be minimized to maximize the energy value of wheat DDGS for poultry. Finally, equations for predicting AME values in layers, broilers, or turkeys from the AME values in roosters are proposed.

Effect of addition of a detoxifying agent to laying hen diets containing uncontaminated or Fusarium toxin-contaminated maize on performance of hens and on carryover of zearalenone

16-wk experiment with laying hens was carried out to examine the effects of feeding of mycotoxin-contaminated maize (CM) on performance, nutrient digestibility, weight of organs, serum chemical parameters, and antibody titers to Newcastle disease virus (NDV) in serum. Also tested were fimbrien antigen K88 in egg yolk and zearalenone (ZON) residues in eggs and tissues. The Fusarium-toxin-contaminated maize contained 17,630 microg deoxynivalenol and 1,580 microg ZON/kg. Moreover, Mycofix Plus (MP), a so-called detoxifying agent, was added to both the uncontaminated control (UCM) and to the CM diet (70% dietary maize inclusion). Each of the four resulting diets (UCM, UCM-MP, CM, CM-MP) was tested on 25 laying hybrids (Lohmann Brown). Feeding of the CM diets significantly depressed feed intake compared to the control groups by approximately 5%. This was mainly due to the effects observed at the beginning of the experiment. Daily egg mass production/hen was 56.6, 58.4, 53.9, and 55.2 g in groups UCM, UCM-MP, CM and CM-MP, respectively. Nutrient digestibility and metabolizability of gross energy were slightly depressed by feeding the CM diets and improved by MP addition. Feeding of the CM diets resulted in a significant decrease in serum titers to NDV and to an increase in yolk titers to antigen K88. No residues of ZON or of its metabolites were found in yolk, albumen, abdominal fat, breast meat, follicles greater than 1 cm in diameter, ovaries including follicles smaller than 1 cm in diameter, magnum, and serum. ZON and alpha-zearalenol (alpha-ZOL) were detected in livers of hens fed the CM diets at mean concentrations of 2.1 and 3.7 microg/kg, respectively. It was concluded that feeding maize which was highly contaminated with Fusarium mycotoxins adversely influenced performance of hens and modulated immune response. At the given level of zearalenone and at the indicated detection limits, no residues of ZON and its metabolites were found in eggs. The effects of the tested detoxifying agent were quite mycotoxin-independent.

Interactions between dietary fat type and enzyme supplementation in broiler diets with high pentosan contents: effects on precaecal and total tract digestibility of fatty acids, metabolizability of gross energy, digesta viscosity and weights of small intestine

One hundred grams fat, based on blends of beef tallow and soya oil (0:100, 20:80, 40:60, 60:40, 80:20 and 100:0) which corresponded to dietary ratios of unsaturated to saturated fatty acids (U:S ratio) of 5.47, 3.23, 2.11, 1.45, 1.00 and 0.69, respectively, was incorporated into a rye-based broiler diet (610 g kg −1). All diets were tested without or with supplementation of a xylanase-containing enzyme preparation in a combined growth test and balance study. Increasing the proportion of dietary tallow resulted in depression in live-weight gain and increased feed conversion ratio, exponential increase in jejunal supernatant viscosity, increased empty weight of small intestine and reduced digestibility of fat and fatty acids and metabolizability of gross energy. The beneficial effect of addition of xylanase was greatest at higher tallow concentrations. In diets which were not supplemented with enzyme, it was shown that small incremental increases in U:S ratio up to ≈1.5 resulted in distinct incremental increases in digestibility, whereas ratios exceeding this value had virtually no further benefit. Such effects were less pronounced in enzyme supplemented groups. In conclusion, addition of an exogenous xylanase to a rye-based broiler diet containing 100 g added fat/kg gives results which very much depend on the U:S ratio. As the ratio increases up to maximum of 1.5 U:S, which corresponds to 40 g soya oil and 60 g tallow/kg, the enzyme effects are greatly pronounced in terms of growth performance, fat and fatty acid digestibility and metabolizability of energy. Beyond this U:S ratio effects of xylanase are more limited.

Comparative evaluation of the effects of coconut oil, oilseeds and crystalline fat on methane release, digestion and energy balance in lambs

The effects of coconut oil, crushed whole oilseeds (rapeseed, sunflower seed and linseed) and rumen-protected crystalline fat on methane release, digestion and energy balance in growing lambs were evaluated in relation to an unsupplemented control diet. The diets consisted of maize silage, grass hay and concentrate which was supplemented with the respective lipid source. On average, the five lipid-supplemented diets contained 56 g ether extract per kg dry matter, whereas the unsupplemented control diet had 31 g kg −1 dry matter The experiment was carried out with 12 lambs in an incomplete 6×6 Latin square with each lamb being fed, subsequently, three different diets for 3 weeks. Feed was allocated according to calculated requirements of metabolizable protein and energy. Gaseous exchange was measured in open-circuit respiratory chambers. Coconut oil supplementation reduced ( p<0.1) methane release per kg live weight by 26% compared to control, and with the use of rapeseed, sunflower seed and linseed the relative reduction was 19%, 27% and 10%, respectively. The effects of the lipid supplementations on methane release were significant when related to gross energy intake ( p<0.05), CO 2 release ( p<0.05) and total energy loss ( p<0.01). A persistence of the methane suppression seems to be given at least partially. Supplementing the oilseeds, particularly sunflower seed, reduced ( p<0.05) the apparent digestibilities of NDF and ADF. This suggests that the reduced fermentation of fiber was also important for the methane suppression by oilseeds whereas with coconut oil treatment the direct inhibitory effects on rumen methanogens might have been predominant. Lipid supplementation, except of rumen-protected fat, reduced rumen fluid ciliate count ( p<0.1) and total VFA concentration ( p<0.05), and depressed the concentration of acetate ( p<0.05) and butyrate ( p<0.001). This diminished ( p<0.05) the ratio of acetate to propionate. The apparent digestibilities of individual fatty acids were relatively high in all groups unless supplied in minute amounts. C 18:0 excretion exceeded intake in all groups presumably due to endogenous excretion or microbial synthesis and, with the oilseeds, possibly also from an enhanced excretion of hydrogenated unsaturated fatty acids of dietary origin. Energy balance remained quite similar with control, crystalline fat and coconut oil, whereas with the oilseeds metabolizability of gross energy and the efficiencies of metabolizable energy utilization tended to be lower.

Effects of dietary fat type and xylanase supplementation in rye containing diets on energy metabolism in male broilers

Xylanase supplementation of rye‐based diets which contained 10% beef tallow was shown to markedly improve the digestibility of fat whereas the enzyme effect in diets containing 10% soya oil was much less pronounced (Dänicke et al. 1997b). Such interactions between fat type and xylanase supplementation have also been reported for wheat–rye‐based diets (Langhout et al. 1997) and wheat‐based diets (Allen et al. 1997) and were attributed mainly to the fatty acid composition of different types of fat and to changes in digesta viscosity caused by soluble pentosan. The apparent metabolizable energy, N‐corrected (AMEN) contents of such diets were affected in a similar manner suggesting that energy metabolism is also influenced by xylanase supplementation and the type of dietary fat. However, changes in the metabolizability of gross energy does not necessarily indicate whether the efficiency of metabolizable energy (ME) for energy gain is changed nor if different proportions of ME are used for maintaining an energy equilibrium, i.e. ME maintenance requirement. In addition, studies suggest that both dietary fat level and fat type might exert effects on the efficiency of utilization of ME for energy retention (Carew and Hill 1964; de Groote et al. 1971; Fuller and Rendon 1979; Brue and Latshaw 1985). Hence, the aim of this study was to investigate the partitioning of ME between maintenance needs and energy retained as protein and as fat when feeding rye‐based diets. The diets contained either soya oil or beef tallow and were either unsupplemented or xylanase‐supplemented.

Energy metabolism in laying hens of different body weight‐genotypes

Energy metabolism and some performance parameters were investigated in laying hens of 3 different body weight‐genotypes: 6×7 (normal‐sized, crossbred from normal‐sized male and female lines, group 1), 47 x 38 (dwarf‐sized, breeding from a dwarf‐sized male line and a normal‐sized female line, group 2) and 44×47 (dwarf‐sized, breeding from dwarf‐sized male and female lines, group 3). Energy balance was measured by indirect calorimetry through C‐and N‐balances in 12 animals of each group during 10 consecutive days at production peak, within the period between the 27th and the 37th week of age. Hens were caged individually at 23°C environmental temperature and fed ad libitum on a laying mash. The mean body weight in the dwarf‐sized groups 2 and 3 was 32% lower than in the normal‐sized group 1 during the energy balance period. The daily gross energy intake in group 2 and 3 was decreased by 33 and 34%, respectively. There were no significant differences in digestibility and metabolizability of gross energy between the groups. The energy requirements for maintenance [kJ ME/kg 0.75 d] derived from the energy balances were lower by 4% (P>0.05) and 14% (P<0.05) in the dwarf‐sized groups 2 and 3 as compared with the normal‐sized group 1, when equal coefficients of partial efficiency of metabolizable energy utilization for energy retention in body and eggs are assumed for the 3 body‐mass genotypes. There were no relevant differences in body composition at the end of the energy balance periods as well as in egg composition between the 3 experimental groups.

Energy metabolism in relation to physical activity in growing pigs as affected by type of dietary carbohydrate.

The effect of dietary carbohydrate source on physical activity in relation to metabolic rate in pigs was studied. Six groups of 12 pigs (50-kg, castrated males) were fed one of two diets: a starch diet or a non-starch polysaccharide (NSP) diet. Both diets had a similar calculated net energy content. The starch diet contained 13% tapioca, and the NSP diet contained 17% sugar beet pulp silage. Pigs were housed in groups and fed at approximately two times maintenance (approximately 900 kJ ME.kg-.75.d-1). Nitrogen and energy balances were measured per group during a 7-d experimental period, which was preceded by a 2-wk adaptation period. Heat production and physical activity were measured during successive discrete 9-min intervals. Metabolizability of gross energy was 79.4% and 78.2% for the starch-fed and NSP-fed pigs, respectively (P < .10). Activity differed between treatments. Activity-related heat production tended to be higher for the starch-fed pigs than for those fed the NSP diet (P < .10); 118 and 90 kJ.kg-.75.d-1, respectively. During the dark phase of the day (from 2000 to 0800) activity-related heat production was 8 kJ.kg-.75.d-1 higher for the starch fed pigs than for those fed the NSP diet (P > .1) whereas during the light phase, this difference was 48 kJ.kg-.75.d-1 (P < .10). Retained energy was similar for both treatments. These results show that dietary composition can change physical activity of pigs and thereby affect their energy utilization.

The effect of proportion of cell-wall material from lucerne leaf meal on apparent digestibility, rate of passage and gut characteristics in pigs

ABSTRACTMetabolism trials were conducted with entire male pigs (average initial weight 44·4 ± 0·2 kg) to determine the apparent digestibility of the major chemical components of diets containing 0·05, 0·10, 0·15 and 0·20 cell-wall material (determined as neutral detergent fibre) from lucerne leaf meal, when added to a constant daily allowance of a semi-synthetic basal diet. Concurrent rate of passage studies were also carried out.Increasing the proportion of cell-wall material in the diet resulted in a linear decrease in the apparent digestibility of dry matter, crude protein and ether extract and the apparent digestibility and metabolizability of gross energy. Daily nitrogen retention (g) increased linearly with an increasing proportion of cell-wall material in the diet. Coefficients of apparent digestibility and cell-wall material fractions did not differ significantly with changes in the dietary proportions.Although the rate of passage of digesta was slower (F &lt; 0·001) in animals fed the diets containing 0·05 and 0·10 cell-wall material than in those fed the two diets with higher proportions, it did not appear to be a major factor contributing to the observed decline in the apparent digestibility of dietary chemical components as the proportion was raised.Increase in dietary proportion of cell wall material was associated with marked linear increase in weight and/or length of various segments of the gastro-intestinal tract.

The Effect of Environmental Temperature on Immune Response and Metabolism of the Young Chicken: 2. Effect of the Immune Response to Sheep Red Blood Cells on Energy Metabolism

We investigated the effect of an immune response, following injection with sheep red blood cells (SRBC) in pullets, on energy balance characteristics and on protein and fat gain. Controls were sham-immunized with phosphate buffered saline (PBS). Feed intake, body weight, rate of gain, and metabolizability of gross energy were not significantly (P>.10) affected by SRBC-immunization. The magnitude and composition of energy gain were influenced by SRBC-immunization. The SRBC-immunized pullets retained significantly (P<.01) more energy, deposited significantly (P<.05) more fat, and had a significantly (P<.01) lower maintenance requirement of metabolizable energy than PBS-injected pullets during days 1 to 5 after injection. During days 6 to 10 after injection, SRBC-immunized pullets deposited significantly (P<.05) less fat and significantly (P<.10) more protein than PBS-injected pullets. Effects of vaccination on metabolic rate and performance characteristics may be comparable with these effects of SRBC-immunization.

Influence of diet and microbial activity in the digestive tract on digestibility, and nitrogen and energy metabolism in rats and pigs

1. Balance trials with respiration measurements were performed with twelve rats and twelve pigs given either low- or high-crude-fibre diets. There were six collection periods with the rats over a live-weight range of 86-264 g and three collection periods with the pigs over a live-weight range of 30-55 kg. Measurements were made on the influence of microbial activity in the digestive tract on digestibility and nitrogen and energy metabolism. Dietary inclusion of the antibiotic Nebacitin was the method used to reduce the microbial population. 2. The microbial activity in the hind-gut (mumol ATP/g air-dry contents) of antibiotic-treated rats was reduced to approximately one-tenth of that of untreated rats. 3. Live-weight gain was not significantly affected in either species by a reduction in the microbial activity, in spite of a reduction in dry matter digestibility in animals with reduced microflora. 4. For rats on low-crude-fibre diets, a reduction in microflora reduced digestibility of all nutrients and energy and metabolizability of digestible energy by approximately 5.4%. All differences were highly significant. On high-crude-fibre diets the decrease was approximately 5.9%. In pigs on both crude fibre levels, the digestibility was also influenced by the level of microflora, but the pattern was somewhat different from that obtained with rats, with the Nebacitin treatment increasing the digestibility of N slightly, and the digestibility of fat markedly. 5. Retained N in rats reached a maximum when the rats were approximately 60 d old and thereafter decreased with increasing age. However, for pigs daily N retention increased with age. The retained N: digested N value decreased linearly with age in the rats, but varied little with age over the range (104-146 d) studied in the pigs. 6. The metabolizability of gross energy (metabolizable energy (ME): gross energy) was significantly reduced with an increase in crude fibre level and by the addition of Nebacitin. 7. Retained energy (RE) in relation to ME (RE:ME), was not significantly affected either by level of microbial activity or by crude fibre. 8. The ratio, RE as fat (RF): RE as protein (RP) increased as the animals grew. In the rat experiment there was a tendency for RP to be higher for animals with normal microflora than for animals with reduced microflora for both crude fibre levels. 9. With rats, the regression analyses indicated that the energy requirement for maintenance could be influenced by both the level of microbial activity in the digestive tract and by the level of fibre in the diet. The net availability of ME for maintenance and growth by rats averaged 0.72 for all treatments. 10. The net availability of ME for growth in the pigs averaged 0.65 for all treatments.

The estimation of the nutritive value of feeds as energy sources for ruminants and the derivation of feeding systems

SUMMARYThe results of 80 calorimetric experiments with sheep and cattle, mostly conducted in Scotland, were analysed using a generalization of the Mitscherlich equation R = B(l–exp(–pG))–l, where R is daily energy retention and G daily gross energy intake, both scaled by dividing by the fasting metabolism. The relations between gross energy and metabolizable energy were also examined. Methods of fitting the Mitscherlich equation and the errors associated with it are presented.It is shown that the gross energy of the organic matter of feed can be estimated from proximate principles with an error of ±2·3% (coefficient of variation) and that provided different classes of feed are distinguished, the metabolizable energy of organic matter can be estimated from gross energy and crude fibre content with an error of ±6·9%. Parameters of the primary equation made with cattle agreed with those made with sheep and there was no evidence of non-proportionality of responses on substitution of feeds in mixtures.The efficiency of utilization of gross energy for maintenance and for body gain of energy was related to the metabolizability of gross energy and, in addition, to fibre or to protein content. Prediction equations are presented which describe these relationships.It is shown that the primary equation can be manipulated to express a number of biological concepts and that its two parameters B and p can be simply derived from estimates of the two efficiency terms for maintenance and production.The results are discussed in relation to the design of feeding systems for ruminant animals and to the derivation of optima in their feeding.