Dynamics of amino acid and protein metabolism in laying hens after the administration of 15N-labeled wheat protein. 10. 15N-labeling of crude protein and amino acids of the oviducts

Over a period of 4 days 12 colostomized laying hens daily received 36 g coarse wheat meal containing 14.37 atom-% 15N excess (15N') together with a conventional ration. After the homogenisation of each oviduct N and 15N' were determined. After the precipitation with TCA the 15N' of the amino acids was analysed in both the precipitate and the supernatant. In addition, the free amino acids and the peptides were determined in the TCA soluble fraction. The atom-% 15N' in the total N and in the non-basic amino acid N showed a parallel decrease; it diminished from 1.75 atom-% 15N' to 0.64. Of the three basic amino acids, lysine shows the lowest labelling at all four measuring points. The quotas of non-basic amino acid 14N and 15N' in the total 14N and 15N' of the oviduct are the same and amount to 53%. In contrast to this, the quota of the 14N of the basic amino acids in the total 14N of the oviduct only amounts to 21.6% and that of 15N' only to 15.4%. The average atom-% 15N' of the free amino acids 12 h after the last 15N application is 1.54 and is considerably above that of the peptides with 1.15 atom-% 15N'. 36 h after the last 15N application the ascertained value of 1.25 is identical in both fractions. The labelling of the free amino acids decreases more quickly than that of the peptides the more time has passed after the last 15N application.     

The effect of exogenous factors on prececal nutrient and amino acid absorption, ascertained from swine with ileo-rectal anastomoses. 3. The effect of crude fiber-rich coarse meal supplements to a basic ration

In digestion trials using pigs fitted with ileo-rectal anastomoses and parallel intact pigs the influence of wheat straw meal (WSM) or grass meal (GM) supplemented on two different levels to a basal diet was examined with regard to nutrient and amino acid digestibility resp. absorption. Both roughages reduced, obviously because of their high cell wall contents, nearly at equal amounts and partly significantly the precaecal as well as the total digestibility of dry matter, organic matter, carbohydrates (= crude fibre + NFE), crude fibre and hemicelluloses (arabinose, xylose). By the roughage supplementations the crude protein digestibility at the terminal ileum was less reduced than at the end of the total digestive tract, the starch digestibility was hardly influenced and that of ether extract mostly increased. In comparison with precaecal glucose and fructose digestibilities it could be shown that the anthrone method is not suitable for determinations of the precaecal digestibility of water soluble carbohydrates. Beside these compounds other substances in the ileum digesta must evidently be dyed by anthrone too. The crude protein digestibility and the amino acid absorption were precaecally hardly or not reduced by WSM supplementations, therefore it can be concluded that it is possible to dilute the energy concentration in diets (e.g. for sows) by addition of WSM without impairing protein digestion and amino acid absorption. The GM supplementations, however, impaired protein digestibility and amino acid absorption of the whole diet, probably caused by the encrusted, possibly heat damaged protein present in the GM itself. When the roughage supplemented diets were fed, the excretion of nitrogen compounds in the faeces was enlarged due to the more intensive bacterial activity in the hind gut and the additional sorption effects to cell wall substances, so that a too low apparent and also true digestibility is made believe. The applicability of the difference method to the calculation of protein and amino acid digestibilities in roughages is very questionable because of their low contents and the missing additivity. The crude fibre and hemicellulose digestibility values calculated by the difference method demonstrate for the both roughages--in spite of high standard deviations--that the precaecal digestibility of crude fibre is about zero and that of the hard lignified hemicellulose fraction in contrast to the predominantly endospermic hemicelluloses of the basal diet is very low. The faecal crude fibre and hemicellulose digestibilities of WSM--especially on the lower supplementation levels--are markedly worse than those of GM.     

The herbicide binding niche of photosystem II-a model

The Q_B 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 Q_B 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).     

Prececal crude protein digestibility and absorption of amino acids from lupines in swine

The apparent precaecal (pc) digestibility of crude protein (CP) and the apparent pc absorption of the key amino acids (AA) lysine, methionine, cystine, isoleucine, threonine and tryptophan from two yellow sweet lupine (L. luteus) varieties (Bornova, Borluta) and one narrow-leafed sweet lupine (L. angustifolius) were determined with ileorectostomized pigs. When the influence of the basal diet (barley or protein free rations) was checked with regard to absorption there were significant differences in a few cases only. In comparison to soybean meal (SBM) the methionine of the lupines was significantly worse, the cystine significantly better absorbed. The CP and the other key AA of the lupines showed approximately the same or even slightly higher pc absorption than those of SBM. With the example of the pc-absorbable AA amounts it was shown that sweet lupines with an approximately equally high CP content as in SBM cannot completely substitute the latter even after lysine and methionine supplementation because the absorbable tryptophan is by far insufficient, and isoleucine and threonine make up only 75% in comparison to SBM. On the basis of the content of pc-digestible CP and pc-absorbable AA it becomes possible to substitute high-grade imported protein concentrates according to their ability of AA supply in the feeding of pigs completely or partly by home-made protein feeds.     

The vitamin A supply of laying hens including during rearing. 1. Testing of mixed feed with a varied vitamin A supplementation in chicks and young hens

In seven experiments with 46,310 young animals from hatching to the 21st week the vitamin A supplement varied between 0 and 10,000 IU per kg mixed feed. Feed intake was significantly diminished in three out of seven experiments when chicken feed was given without vitamin A supplement. In the young chicken period 1,500 IU vitamin A supplement were sufficient for optimal body weight development, in the young hen period native carotene was sufficient. The variation of the body weight of the individual animals on the 126th day did not show any connection with vitamin A supply. The carotene content of the rations was sufficient to prevent deficiency symptoms. The livers and yolk sacs of one-day-old chickens on average contained 114 and 56 IU vitamin A/g substance when the parents had received mixed feed with 15,000 IU vitamin A/kg. There is a positive relation between the vitamin A supply of the young chickens and hens and the vitamin A content of the liver.     

Vitamin A requirements of growing swine. 3. Effect of vitamin A supply on the state of health of piglets and fattening swine

Diseases and losses were registered in dependence on vitamin A supply with 2,035 pigs (6.5-114 kg live weight). The histologic examinations comprised various organs of 72 animals. The content of the main protein fractions as well as antibody titre after supplementing antigenes were determined in the serum of 104 animals. The feeding of a vitamin-A- and carotinefree casein-starch-respectively a Vitamin-A-free cereal-soybeanmeal-diet led to deficiency symptoms after 7-8 respectively 16-19 weeks of experiment particularly in the shape of nervous disturbances and voice affectations. Histologically a hyperplasia and a metaplasia of the epithelium of the big ducts in the salivory gland could be proved. The repletion of a part of the avitaminotic animals by means of oral (500 I.U./kg feed) and parenteral (500,000 to 1,000,000 I.U. i.m.) vitamin A administration is proof of a lack of vitamin A. Vitamin A and provitamin dosage did not influence diseases and losses with the exception of the occurrence of deficiency symptoms. The protein content of the serum as well as that of the globulin fractions alpha, beta, gamma did not change, the albumin content was lower in the groups without vitamin A (p greater than 0.05). Antibody titre against the lipopolysaccharide of salmonella dublin and human gamma globulin were diminished in piglets and fattening pigs fed vitamin A free (p less than 0.05). Taking the criterion of animal health, a vitamin A requirement higher than for growth (250 I.U./kg feed) cannot be derived.     

The effect of exogenous factors on pre-cecal nutrient and amino acid resorption determined in swine with ileo-rectal anastomoses. 2. The effect of the degree of grinding of plant protein-rich concentrates in rations

In digestion trials using pigs fitted with ileo-rectal anastomoses and intact pigs, the influence of two different grinding finenesses (coarse, fine) of vegetable high-protein concentrates (soya bean meal, field bean, lupin) added to cereal diets was examined. It was found that neither the precaecal nor the total nutrient absorption and digestibility were practically injured, when in the concentrates the particle sizes bigger than 2 mm did not amount more than 20% and whole grains hardly occurred. The investigations concerned the crude putrients, watersoluble carbohydrates and starch as well as the indispensable and dispensable amino acids. The apparent and true precaecal absorption values and total digestibility data for soya bean meal (heat treated), field bean (variety 'Fribo' and yellow sweet lupin (variety 'Bornova'--calculated by the different method--are given and discussed.