排序方式： 共有17条查询结果，搜索用时 359 毫秒
1.
Wolfgang Siegert Christian Ganzer Holger Kluth Markus Rodehutscord 《Journal of animal physiology and animal nutrition》2019,103(3):723-737
In this study, we determined whether deficient dietary amino acid (AA) concentrations influence the precaecal (pc) AA digestibility when determined using the regression approach. We mixed two basal diets. Basal diet 1 was deficient in essential AAs, whereas adequate AA concentrations were ensured in basal diet 2 by adding free AAs. Rapeseed cake and full‐fat soya beans as test ingredients were included in the basal diets at levels of 100 and 200, and 150 and 300 g/kg, respectively, at the expense of maize starch. Each diet was tested with six replicates of 10 broiler chickens each. The feed intake of the chickens that were fed diets based on basal diet 2 was similar, whereas the feed intake of the chickens that were fed diets based on basal diet 1 differed considerably. The numerical differences in pc AA digestibility determined with basal diet 1 or 2 ranged from 2.6 percentage points to 20.8 percentage points in rapeseed cake and from 0.5 percentage points to 15.2 percentage points in soya beans. Across all measured AAs, the average differences were 10.1 percentage points and 5.4 percentage points in rapeseed cake and soya beans, respectively. The differences in the estimated pc AA digestibility between the basal diets were probably caused by different basal endogenous AA losses in the digesta between treatments as a consequence of different feed intake. Adequate AA concentrations and test ingredient levels that are specifically adjusted to avoid a negative effect on feed intake are recommended for future studies. 相似文献
2.
The effect of a continuous duodenal infusion of L-histidine (His) (8 g/d) on the retention of nitrogen was investigated in two experiments (I, II), each of which was carried out using two young bulls. In Exps. I and II, the animals (150-250 kg BW) were fitted with a re-entrant cannula in the proximal duodenum and were fed diets containing 125 g CP/kg DM and 11.5 MJ ME/kg DM. A third experiment (III) using two young bulls (140-200 kg BW) fitted with a simple T-cannula was carried out infusing 6 g L-His. The animals were fed a low protein diet (94 g CP/kg DM and 11 MJ ME/kg DM). The study was done to find out whether or not L-His is the first limiting amino acid (AA) for growing ruminants. N retention was 28 and 31, 38 and 38, 22 and 24 g/d without L-His infusion and with L-His infusion for Exps. I, II and III, respectively. Both in the experiments with a standard protein supply (I, II) and in the experiment with reduced protein supply (III), no significant differences were found between periods with and without infusion of L-His. The utilisation of duodenal NAN varied between 39% and 50% and was also not significantly influenced by the duodenal infusion of L-His. No significant effect was observed on the flow of AA into the duodenum. The faecal excretion of AA was also not significantly influenced by the infusion of L-His. The utilisation of individual amino acids as calculated by the ratio of retained AA to intestinal apparently digested AA, did not differ significantly following the duodenal infusion of L-His. As expected, the utilisation of His decreased. Of the different essential AA, L-His was the most utilised (80%) followed by Arg (72%), Met (60%), Leu (45%) and Lys (44%), during periods without supplementation of L-His. It is concluded that the intestinal supply of L-His from the basal diet was sufficient for the potential growth level of animals under these experimental conditions. In all AA present at the proximal duodenum, L-His could have at first a limiting effect on the performance of growing young bulls with high body gain. Arg and Met, but not Lys, could be second or co-limiting AA. 相似文献
3.
Klaus G. Tietjen Joachim F. Kluth Roland Andree Michael Haug Markus Lindig Klaus H. Müller Heinz J. Wroblowsky Achim Trebst 《Pest management science》1991,31(1):65-72
The QB binding niche of photosystem II is also the binding site for many different herbicides. In order to understand the mode of binding of the herbicides, a 3-dimensional model of the binding niche was constructed. The model was based upon a comparison of the known structure of the QB binding niche in purple bacteria with sequence and mutant data of the D-1 protein of photosystem II. Plastoquinone builds up hydrogen bonds to phenylalanine 265 backbone amide nitrogen, to serine 264 hydroxyl, and to histidine 215 delta-1 nitrogen. In addition to these hydrogen bond donors and acceptors, herbicides can build up hydrogen bonds to backbone carbonyl of alamine 263 and to serine 268 hydroxyl. This is supported by binding data of inhibitors in Chlamydomonas reinhardtii chloroplasts of wild type and of five D-1 protein mutants (Ser264 Ala, Ala251 Val, Phe255Tyr, Val2191le, Leu275Phe). 相似文献
4.
1. Herein, it was investigated whether different particle size distributions of feed ingredients achieved by grinding through a 2- or 3-mm grid would have an effect on precaecal (pc) amino acid (AA) digestibility. Maize and soybean meal were used as the test ingredients.
2. Maize and soybean meal was ground with grid sizes of 2 or 3 mm. Nine diets were prepared. The basal diet contained 500 g/kg of maize starch. The other experimental diets contained maize or soybean meal samples at concentrations of 250 and 500, and 150 and 300 g/kg, respectively, instead of maize starch. Each diet was tested using 6 replicate groups of 10 birds each. The regression approach was applied to calculate the pc AA digestibility of the test ingredients.
3. The reduction of the grid size from 3 to 2 mm reduced the average particle size of both maize and soybean meal, mainly by reducing the proportion of coarse particles. Reducing the grid size significantly (P < 0.050) increased the pc digestibility of all AA in the soybean meal. In maize, reducing the grid size decreased the pc digestibility of all AA numerically, but not significantly (P > 0.050). The mean numerical differences in pc AA digestibility between the grid sizes were 0.045 and 0.055 in maize and soybean meal, respectively.
4. Future studies investigating the pc AA digestibility should specify the particle size distribution and should investigate the test ingredients ground similarly for practical applications. 相似文献
5.
1. The objectives were to study the variation in amino acid (AA) digestibility of rapeseed meal in laying hens and to investigate whether the variation in AA digestibility can be explained by chemical constituents of the rapeseed meal. Nine rapeseed meals from different processing plants operating in Germany were used. The crude protein and crude fibre concentrations of the meals ranged from 367 to 410 and 137 to 175?g/kg dry matter (DM), respectively. The concentrations of total glucosinolates varied between 5·1 and 12·9?mmol/kg DM. Each meal was included in one of the experimental diets at an inclusion level of 200?g/kg at the expense of maize starch. 2. A total of 16 Lohmann Brown laying hens were used for this experiment and were surgically caecectomised. They were housed individually in metabolism cages. Each of the 10 diets was fed to at least 6 hens in 4 periods of two weeks duration. Excreta were collected during the last 5?d of each period. The digestibility coefficient of AA was calculated for each diet. The digestibility of the rapeseed meals was calculated by multiple linear regression analysis. 3. Mean essential AA digestibility of rapeseed meals varied between 0·78 and 0·84. Among the essential amino acids, the highest level of digestibility was found for arginine (0·88) and methionine (0·87), and the lowest for lysine (0·74) and threonine (0·75). The highest variation between rapeseed meals in digestibility was found for threonine (0·68 to 0·79) and lysine (0·68 to 0·78). The concentration of neutral detergent insoluble nitrogen of the rapeseed meals was negatively correlated with the digestibility of lysine, but was not significantly correlated with digestibility of any other AA. Glucosinolate concentration was significantly correlated with valine digestibility. 4. Multiple regression analysis showed that the concentrations of crude protein and ash together were the major factors considered to explain variation in digestibility of essential AA. Additional consideration of neutral detergent insoluble nitrogen and total glucosinolates improved the goodness of fit only marginally and was unlikely to be of practical significance. 相似文献
6.
Kluth H Engelhard T Rodehutscord M 《Journal of animal physiology and animal nutrition》2003,87(7-8):280-291
The amount of crude protein entering the small intestine (nXP) and the nitrogen balance in the rumen (RNB) are the two components of the German protein evaluation system. Although there is no scientific evidence, feeding strategies for the practice imply an excess in RNB, particularly in diets for high-yielding cows. This study was undertaken to investigate whether cows benefit from an excess in RNB under conditions of sufficient nXP supply. Three rations were used equal in energy (7.2 MJ net energy for lactation per kilogram dry matter; DM) and nXP (173 g/kg DM) and mainly based on silages from maize, grass, and brewer's grains as well as ground barley and solvent extracted meals from rapeseed and soybeans. Three rations were calculated to allow for an RNB of either 0 or 50 g/day. RNB was adjusted by either a supplementation of urea or a change in the proportions of oilseed meals. The intended levels of energy, nXP and RNB in the diets were confirmed under consideration of separate digestibility measurements with wether sheep and a chemical fractionation of dietary crude protein. The rations were offered as total mixed rations. At least 35 cows between days 21 and 98 of lactation were used per treatment. Cows were milked three times daily and had continuous access to feed and water. Feed intake was measured continuously and for each cow individually by a feeder system through which the rations were offered. The average values for the three treatments ranged between 20.1 and 21.7 kg/day for DM intake, 43.0 and 44.0 kg/day for milk yield, and 1.39 and 1.42 kg/day for milk protein yield. No significant treatment effect was detected in any of the monitored criteria. Cows were in a negative energy budget as indicated by a loss in backfat thickness, similar for all treatments. Under inclusion of literature data it is concluded that under conditions of a sufficient nXP supply, dairy cows do not need an excess in RNB in total mixed rations, even at very high levels of milk protein yield. 相似文献
7.
The susceptibility of intercrop species (Raphanus sativus, Brassica juncea, B. rapa, Sinapis alba and Phacelia tanacetifolia) to the sugar beet pathogen Rhizoctonia solani was investigated in vitro, in the greenhouse and in the field with artificial inoculation. Disease severity in subsequently cultivated sugar beet was monitored in the field. Differences in susceptibility between species were found to be consistent in all experimental systems. All intercrop species were susceptible to R. solani. Brassica rapa and R. sativus were less susceptible than P. tanacetifolia. Compared to fallow, the cultivation of B. rapa and R. sativus reduced disease severity in subsequently grown sugar beet (median ratings of up to 3·0 and 3·5, respectively, depending on environmental conditions). This resulted in higher white sugar yield compared to fallow (up to 210% and 157% for B. rapa and R. sativus, respectively). This study demonstrates that in vitro and greenhouse resistance tests are suitable systems to predict the effects of intercrop species susceptibility in the field on disease severity and white sugar yield in subsequently grown sugar beet. Intercrop breeding programmes might profit from fast and efficient screening tests to provide Rhizoctonia‐resistant intercrops as an additional control measure against R. solani in sugar beet. 相似文献
8.
Jeannette Boguhn H Kluth O Steinh?fel Martina Peterh?nsel M Rodehutscord 《Archives of Animal Nutrition》2003,57(4):253-266
The aim of the present study was to determine equations that predict ME in total mixed rations (TMR) based on routine methods. The ME content of 30 TMR for dairy cows was determined based on digestible crude nutrients obtained with wether sheep. Concentrations in the TMR (in g/kg DM) varied between 118 and 234 for crude protein, 26 and 48 for crude lipid, 131 and 250 for crude fibre, 281 and 488 for NDF, and 173 and 304 for ADF. Gas production ranged from 40.7 to 54.1 ml/200 mg DM, and enzymatically degraded organic matter from 652 to 800 g/kg DM. Digestibility [%] ranged from 68.6 to 84.0 for organic matter, from 55.6 to 84.3 for crude lipid, from 55.0 to 77.8 for crude fibre, from 57.6 to 77.0 for NDF and from 53.1 to 79.6 for ADF. ME ranged from 9.6 to 11.9 MJ/kg DM, and NEL from 5.7 to 7.4 MJ/kg DM. ME content was highly correlated with the concentration of both crude fibre and enzymatically degradable organic matter as well as with organic matter digestibility. A multiple regression equation based on crude fibre and crude lipid predicted ME with a reasonable goodness of fit (r2 = 0.81; s(y.x) = 2.4%). The inclusion of other nutrients, of neutral and acid detergent fibre, neither of gas production did improve the goodness of fit. The best prediction was achieved with inclusion of enzymatically degraded organic matter (r2 = 0.90; s(y.x) = 1.7%). 相似文献
9.
Bulang M Kluth H Engelhard T Spilke J Rodehutscord M 《Journal of animal physiology and animal nutrition》2006,90(3-4):89-102
Studies on the use of lucerne silage as a forage source for high-yielding dairy cows. It was the main objective of this study to investigate effects of lucerne silage inclusion in maize silage-based rations on dry matter intake, milk yield and metabolic parameters of high yielding dairy cows. Three total mixed rations (TMR) were used. They contained as the main forage source on a dry matter basis 41.5% maize silage and 12% grass silage (ration maize) or 18% maize silage and 29% of either grass silage (ration grass) or lucerne silage (ration lucerne). Organic matter digestibility, determined with wether sheep, was 77 and 65% for the grass and the lucerne silage, respectively. Each TMR was fed to 4 wether sheep to determine crude nutrient digestibilities. The content of net energy for lactation (NEL), as calculated from digestible crude nutrients, was (MJ/kg dry matter (DM)): 7.1 (maize), 7.2 (grass) and 6.8 (lucerne). Based on the results of a chemical fractionation of crude protein it was calculated that the content of utilisable crude protein (nXP) was not below 167 g/kg DM and that the N balance in the rumen was not negative for all 3 TMR. The TMR were fed for 169 days to at least 28 dairy cows per treatment which were in their first half of lactation. Feed intake, milk performance data and physiological indicators were measured for each individual cow. The DM intake was significantly higher in treatment lucerne (23.2 kg/d) than in treatments grass (21.2 kg/d) and maize (22.6 kg/d). Daily intakes of NEL and nXP were significantly lower in treatment grass than in the other two treatments. Milk yield was significantly higher in treatment maize (41.7 kg/d) than in treatments grass (37.3 kg/d) and lucerne (38.5 kg/d). This was associated with a significantly lower milk fat content in treatment maize (3.5%) in comparison with the other two treatments (3.9% each). Milk protein content was unaffected by treatment (3.4% on average). Similarly, the acetone content of milk was not significantly different between treatments. The beta-hydroxybutyrate content of the deproteinized blood was significantly higher in treatment lucerne at start of lactation, but this difference disappeared in subsequent parts of the experimental period. Measurements of back fat thickness indicated mobilisation and retention of energy by cows during the experimental period to be similar in all treatments. It is concluded that lucerne silage is a suitable forage source for high yielding dairy cows in spite of its low digestibility. 相似文献
10.
H. Kluth M. Gabel J. Voigt U. Schönhusen 《Journal of animal physiology and animal nutrition》2000,84(5):136-147
The objective of this study was to quantify endogenous nitrogen (N) recycled for microbial protein synthesis in the rumen. Four growing bulls (Schwarzbuntes Milchrind; bodyweight: 240–310 kg) with duodenal T‐shaped cannulas were fed diets containing four levels of crude protein content (200, 156, 102 and 63 g/kg dry matter, respectively). The diets were based on wheat, barley, tapioca meal, soybean extracted meal, dried beet pulp, meadow hay and straw. The diets had an energy level of 11.1, 10.9, 10.2 and 9.6 MJ metabolizable energy/kg dry matter. Faeces and urine were collected in four 7‐day balance periods. Duodenal flow rate was estimated by TiO2, pelleted with grain, as a marker. The relationship between urine N excretion, the amount of microbial N reaching the duodenum, ruminal N balance and N retention were examined and the amount of endogenous N available for microbial protein synthesis without negative effects on the N retention was determined. It can be concluded that up to 16% of the microbial N supply could be covered by recycled endogenous N, but N retention should not be decreased by more than 1.5 residual standard deviations of maximal N retention. 相似文献