Gelatin Diet Research Articles

Effects of amino acid supplementation of dietary proteins on serum cholesterol and fatty acids in rats

A 120 d feeding study with adult rats was conducted to investigate the effects of amino acid supplementation of casein and gelatin (based on differences in the amino acid profiles of the two protein sources) on blood lipid parameters (total cholesterol, HDL-cholesterol and fatty acid composition of phospholipids). The concentrations of total cholesterol and HDL-cholesterol were significantly (P < 0.05) higher in rats fed on unsupplemented casein diet compared with those fed on the unsupplemented gelatin diet. Supplementation of casein with glycine or glycine+arginine (amino acids present in large amounts in gelatin) significantly (P < 0.05) reduced concentrations of total serum cholesterol. However, supplementation of gelatin with glutamic acid, methionine, phenylalanine or tyrosine or a mixture of these four amino acids (present in large amounts in casein) had no effect on total serum cholesterol. Supplementation of gelatin with a mixture of glutamic acid, methionine, phenylalanine and tyrosine significantly (P < 0.05) reduced the concentration of stearic acid (18: 0) and elevated the concentration of palmitoleic (16:1 n-7) and oleic (18: 1 n-9) acids in blood, suggesting increased formation of these monounsaturates from their precursor fatty acids by promotion of the activity of Δ9 desaturase by the mixture of the supplemental amino acids. However, supplementation of gelatin with a mixture of the four amino acids significantly (P < 0.05) increased the concentration of linoleic acid (18: 2 n-6) and decreased concentrations of arachidonic acid (20:4 n-6) and other C 20 and C 22 n-6 long-chain polyunsaturated fatty acid ( n-6 LC-PUFA) metabolites of linoleic acid, suggesting a slowing of the linoleic acid to n-6 LC-PUFA pathway.

Bioavailability of niacin from feed ingredients commonly used in feeds for channel catfish, Ictalurus punctatus

A catfish bioassay for available niacin was developed using liver NAD levels as the response measure. Triplicate groups of fingerling channel catfish were fed 7 different feed ingredients as the sole source of dietary niacin in a basal casein–gelatin diet for 8 weeks. Three other experimental diets containing known amounts of supplemental niacin (6, 9 and 12 mg/kg diet, respectively) were also fed to triplicate groups of fish to establish the levels of NAD in the liver after 8 weeks. A standard linear regression equation of available niacin in diet ( y in mg/kg) as a function of liver NAD concentration ( x in μmol/g) was derived and used to determine the amount of available niacin in the feed ingredients. Menhaden fish meal (MFM), meat and bone/blood meal (MBM), wheat middlings (WML), cooked corn (CCO), uncooked corn (UCO), cottonseed meal (CSM) and soybean meal (SBM) contained 105.3, 50.5, 153.3, 21.9, 12.8, 22.5 and 20.3 mg/kg of available niacin, respectively. When compared to the total niacin content of each feed ingredient, niacin in animal tissue (MFM, MBM) was totally available to channel catfish. Availability of niacin in cereals and cereal byproducts, WML, CCO and UCO, was about 60, 44 and 28%, respectively. Niacin availability in the two oilseeds, CSM and SBM, was found to be 58 and 57%, respectively. Niacin availability from corn was increased by about 57% when the corn was extrusion-cooked. It was concluded that supplementation of niacin may not be needed or can be lowered in typical commercial catfish feeds because of the relatively high amount of available niacin found in the feed ingredients.

Effect of Low Dietary Magnesium on Immune Response and Osmoregulation of Atlantic Salmon

Abstract The influences of dietary magnesium on immune response and on osmoregulation in parr of Atlantic salmon Salmo salar were determined. Groups of fish were fed a casein–gelatin diet unsupplemented (containing about 200 mg Mg/kg) or supplemented with either 300 or 500 mg Mg/kg dry diet (as MgSO4) for 12 weeks before vaccination to produce fish with different Mg levels, and the feeding regime was continued throughout the study. No differences were observed between the treatment groups in serum-specific antibody levels every second week for 8 weeks after vaccination against Vibrio anguillarum serotypes O1 and O2. Both lysozyme levels and spontaneous hemolytic activities in serum were elevated in vaccinated fish compared with unvaccinated fish. Neither lysozyme activity, complement hemolytic activity, total protein in serum nor blood hemoglobin were affected by dietary Mg. The spontaneous hemolytic activity in serum was lower in fish fed the unsupplemented diet and highest in fish fed the diet supplemen...

NAD +]/[NADH] redox-state metabolites of freezed-clamped livers of rats fed casein or gelatin diets

Postprandial thermic effects of dietary protein meals have been hypothesized to be related to a diet-mediated increase in amino acid oxidation that may affect the in vivo redox states. The objective of the present study was to determine the effects of isoenergetic isonitrogenous restricted (80% of the ad libitum gross energy intake) diets containing either casein (30%) or gelatin (15% casein, and 12.7% gelatin) for 1, 3, or 28 days to Wistar rats on liver metabolites characterizing cytoplasmic and mitochondrial redox-states. Both casein and gelatin diets produced a progressive decline in the concentrations of lactate and an increase in the concentrations of acetoacetate with the duration of feeding. β-hydroxybutyrate concentrations were reduced on day 3 in relation to day 1 and were highest on day 28. Pyruvate levels changed moderately or stayed the same. The calculated redox ratios were increased in cytoplasm on day 3 and 28 in relation to day 1 and were insignificantly higher with the gelatin diet compared with the casein diet. The corresponding redox ratios in mitochondria were increased on day 3 and remained high on day 28 in relation to day 1 and were significantly higher on day 28 in the gelatin diet-fed group in relation to the casein diet-fed group. Adenine nucleotide content and energy charges were only slightly modified by the experimental conditions used. It is suggested that these results are in accordance with a stimulation of amino acid oxidation and reoxidation of reducing equivalents feeding the protein diets.

Dietary regulation of rat intestinal angiotensin-converting enzyme and dipeptidyl peptidase IV.

The small intestinal brush-border membrane contains several peptidases that are involved in the hydrolysis of dietary peptides containing proline. A high-proline (gelatin) diet was administered to one of several groups of rats to study its possible regulatory effect on levels of two prolyl peptidases, namely angiotensin-converting enzyme (ACE) and dipeptidyl peptidase IV (DPP IV). Groups of rats were maintained on isocaloric diets containing either low (4%), normal (17%), or high (50%) protein (casein) or high (50%) gelatin. After 7 days, brush-border membranes and total RNA were prepared from the small intestine. ACE activity was 3- to 10-fold higher in brush-border membranes from the gelatin group compared with the low-protein group. DPP IV exhibited a three- to sixfold increase. Immunoblot analysis of brush-border membrane-associated ACE protein indicated a six- to eightfold increase in the high-gelatin group. There was also a 1.5- to 3-fold increase in steady-state levels of ACE and DPP IV mRNA. These results suggest that a diet high in proline (gelatin) is particularly effective in increasing intestinal levels of these two enzymes.

The Quality and Quantity of Dietary Protein Affect Brain Protein Synthesis in Rats

The influence of the amino acid supply in diets with different quality and quantity of protein on the rate of protein synthesis in the brain was investigated. Amino acid concentrations in serum and brain altered in accordance with the amino acid levels of the diets, with the exception of some amino acids such as aspartic acid, glutamic acid, glycine and threonine. When rats were fed various levels of dietary casein (0, 5 and 20%), the aggregation of ribosomes increased and the fractional rate of protein synthesis tended to increase with the increase in dietary protein. When rats were fed a 20% casein diet, greater aggregation of brain ribosomes and protein synthesis rate were observed compared with those in rats fed 20% wheat gluten or gelatin diets. The RNA activity was related to the degree of the aggregation of brain ribosomes and the fractional rate of protein synthesis.

Choline Requirement of Swim-Up Rainbow Trout Fry

Abstract Triplicate 150-fish lots of first-feeding fry of rainbow trout (Oncorhynchus mykiss; initial mean weight, 0. 12 g) were fed casein–gelatin-based diets containing 0, 200, 400, 800, 1,000, 2,000, 4,000, or 8,000 mg choline/kg of feed for 12 weeks to determine their need for dietary choline. Although the growth rates of fry were suboptimal, results showed that fry needed no more than 4,000 mg choline/kg casein–gelatin diet for maximum growth and 2,000 mg/kg for maximum body fat and minimum protein. Survival was significantly lower for fish fed 800 mg choline/kg of diet than for those fed greater amounts of the nutrient. These results suggest that the dietary choline requirement of early feeding salmonids is greater than that previously reported for older salmonids. The amount of choline needed by fishes apparently decreases with age or size.

Effect of supplementation of each limiting amino acid to a low soy protein isolate, corn gluten or gelatin diet on brain tryptophan and 5-hydroxyindoles in rats.

The neurochemical changes caused by supplementation of a limiting amino acid (methionine, lysine or tryptophan) to a 5% protein diet (soy protein isolate, corn gluten or gelatin) were investigated. The final levels of each supplemented amino acid were 2- or 4-fold each requirement level in the diets. The supplementation of methionine to the soy protein isolate diet reduced the contents of brain 5-hydroxyindoles (serotonin and 5-hydroxyindole acetic acid (5HIAA)). With lysine supplementation to the corn gluten diet, the brain 5-hydroxyindole contents did not change. Tryptophan supplementation to the gelatin diet caused a significant increase in the brain 5- hydroxyindoles. When rats were fed the soy protein isolate diet supplemented with methionine for a 5-hr period on one day (acute) or on 30 days (chronic), the concentrations of brain 5-hydroxyindoles sharply decreased and remained decreased for 30 days. Good correlations between serum tryptophan, and brain tryptophan and 5-hydroxyindoles were found on m...

The Influence of High Glycine Diets on the Activity of Glycine-Catabolizing Enzymes and on Glycine Catabolism in Rats

Male albino rats were adapted to isocaloric purified diets that differed mainly in their glycine and casein contents. Controls received a 30% casein diet. In experimental diets gelatin or gelatin hydrolysate was substituted for half of the 30% casein. An additional group was fed a glycine-supplemented diet, which corresponded in glycine level to the gelatin diet but in which the protein level was nearly the same as that of the casein control diet. Another group received a 15% casein diet. Rat liver glycine cleavage system, serine hydroxymethyltransferase and serine dehydratase activities were measured. 14CO2 production from the catabolism of 14C-labeled glycine was measured in vivo and in vitro (from isolated hepatocytes). Serine dehydratase and glycine cleavage system activities were higher in animals fed 30% casein diets than in those fed 15% casein diets. Serine hydroxymethyltransferase activity of the cytosolic and mitochondrial fractions was highest when a high glycine diet (glycine administered as pure, protein bound in gelatin or peptide bound in gelatin hydrolysate) was fed. 14CO2 formation from [1-14C]- and [2-14C]glycine both in vivo and in isolated hepatocytes was higher when a high glycine diet was fed than when a casein diet was fed. These results suggest that glycine catabolism is dependent on and adaptable to the glycine content of the diet. Serine hydroxymethyltransferase appears to play a major role in the regulation of glycine degradation via serine and pyruvate.

Protein turnover of breast muscle in germ-free and conventional chicks.

The effect of the gut microflora on protein turnover in pectoral muscle (M. pectoralis profundus) was studied by means of dietary infusion of L-[U-14C]phenylalanine and of massive dose injection of L-[4-3H]phenylalanine in chicks fed on a semi-purified casein-gelatin (SCG) diet until 19 d of age, and in those subsequently given either a nitrogen-free (NF) diet or NF supplemented with methionine and arginine (MA) for a further 9 d. Time-course changes in radioactivity released in expired carbon dioxide during the 8 h infusion period showed that isotopic equilibrium was reached in 4 h with the SCG diet and in 5 h with the MA diet. However, with the protein-deprived chicks given the NF diet, isotopic equilibrium was not achieved since radioactivity in CO2 increased linearly throughout. On feeding the NF diet, fractional protein synthesis rate and the absolute amount of protein synthesized in chick breast muscle were reduced. These reductions were partially alleviated by supplementing the NF diet with methionine and arginine. The fractional degradation rate of breast muscle was increased in chicks given the NF diet, while the absolute amount of protein degraded was decreased. The addition of methionine and arginine counteracted these changes brought about by protein starvation. Generally speaking, the presence of the gut microflora had little, if any, effect on protein turnover rate in chick-breast muscle.

Effect of Dietary Calcium Phosphate and Zinc Supplementation on Whole Body Zinc Concentration of Rainbow Trout (Salmo gairdneri)

Groups of rainbow trout (Salmo gairdneri) were fed casein–gelatin diets supplemented with calcium phosphate (Ca3(PO4)2) to produce dietary calcium and phosphorus levels of 1,2, or 4% and 0.9,1.5, or 2.4%, respectively (low, medium, or high calcium phosphate), and supplemented with 20 μg Zn/g diet as ZnSO4, zinc proteinate, or ZnSO4 + EDTA (1000 μg/g). Dietary calcium phosphate levels had no significant effect on weight gain of the fish, although the fish fed the high dietary calcium phosphate level were smaller than the rest. Dietary zinc supplementation had no effect on growth, but significantly increased whole body zinc levels in fish fed diets containing low or medium calcium phosphate. In fish fed diets containing low calcium phosphate, the zinc supplements all increased whole body zinc concentrations. In fish fed diets containing medium calcium phosphate, supplementation with zinc proteinate resulted in higher whole body zinc values than supplementation with other zinc sources. Dietary zinc supplementation did not increase whole body zinc concentrations above control levels in fish fed the experimental diets containing high calcium phosphate. We conclude that increased dietary levels of calcium phosphate reduced whole body zinc concentration of rainbow trout and that 20 μg Zn/g diet was insufficient to overcome this reduction at the highest dietary calcium phosphate level regardless of the form of zinc supplement used.

The influence of the gut microflora on protein synthesis in liver and jejunal mucosa in chicks.

Protein synthesis in liver and jejunal mucosa was measured in 19-d-old germ-free (GF) and conventional (CV) chicks fed on a semi-purified casein-gelatin (SCG) diet using a massive-dose single injection of [U-14C]phenylalanine. The effect of subsequent feeding for 9 d either a nitrogen-free (NF) diet or an NF diet supplemented with L-methionine (5 g/kg) and L-arginine hydrochloride (2 g/kg) (MA diet) was investigated in both types of chick. In the liver, apart from the amount of DNA, the values for wet weight, protein, RNA, fractional synthesis rate (FSR) and the amount of protein synthesized were reduced after feeding the NF diet and, to a lesser extent, the MA diet. Except that the total amount of liver DNA was higher in the CV chicks than in their GF counterparts (P less than 0.01), no environmental effect was significant. When expressed on a unit body-weight basis, liver weight, protein, RNA and DNA were significantly higher in the CV than in the GF chicks. In the jejunal mucosa, the values for wet weight, protein and RNA tended to be reduced after the NF treatment but increased after the MA treatment. Mucosal DNA and the amount of protein synthesized (microgram/mm per d) were significantly reduced after the NF diet but were less affected after the MA diet. Mucosal protein FSR and the amount of protein synthesized per mg RNA were significantly reduced after both dietary treatments. No difference was found among dietary treatments in the amount of protein synthesized per mg DNA in jejunal mucosa. Mucosal DNA was significantly higher in the CV chicks and the reverse was true for mucosal protein: DNA. It was suggested that the increased protein synthesis in jejunal mucosa and possibly in liver on supplementation of an NF diet with methionine and arginine would partly, if not completely, account for the N-sparing effect of these amino acids. Although the protein: DNA value was smaller in CV chicks, the FSR and the amount of protein synthesized tended to be higher than in their GF counterparts irrespective of nutritional status. This might imply that protein degradation rate is greater in the CV state.

Effects of quantity and quality of dietary protein on the jejunal absorption activities for L-leucine and glycylglycine in rats.

In order to study the variability of intestinal transport systems for amino acid and peptide, the effects of quantity and quality of dietary protein on the absorption of L-leucine and glycylglycine were investigated in situ in the rat jejunum. The absorption activities for both amino acid and dipeptide changed in a similar manner in response to the dietary levels of casein ; decreasing below 10%, remaining nearly constant between 10 and 50%, and increasing above a 50% casein level. Similar results were obtained with wheat gluten. At an equal dietary protein level (equivalent to 10% casein), the absorption activities for L-leucine and glycylglycine in rats fed with a zein or gelatin diet were lower than those in animals fed with a casein or gluten diet. A high correlation was observed between the absorption activity for L-leucine and that for glycylglycine in all dietary groups. The results clearly indicate that jejunal absorption activity for glycylglycine could be altered in parallel with that for L-leucine by changes of the quantity and quality of dietary protein.

Effect of coating amino acids with casein supplemented to gelatin diet on plasma free amino acids of carp.

Levels of free amino acids were examined in plasma of carp at 0.5, 1, 1.5, 2, 3, 4, 6, 8, 12, and 24 hours after being fed casein-gelatin (control), gelatin (diet 2), and gelatin diet with essential amino acids uncoated (diet 3) or coated with casein (diet 4). Also, the balance of essential amino acid in plasma (BEAAp) was calculated in a manner similar to that for the determination of EAA index, using those of the control group as references. Almost all EAA in fish fed diets 3 and 4 reached maximal levels and dropped to fasting lvevls faster than in fish fed the control diet. In fish fed diet 4, levels of tryptophan were higher, but those of leucine were lower throughout the 1-8 hour period, than in fish fed diet 3; levels of all EAA (except lysine and arginine) from fish fed diet 2 remained low, with vague peaks at 4 hours. Values for BEAAp in all treatments droppid to the lowest values at 6 hours after feeding. Those for diets2, 3, and 4 were 32.3, 57.9, and 86.7% respectively and those from diet 4 were always higher than those from diet 3. Highly significant correlations between the BEAAp value at 6 hours and the average weight gain, feed effciency, or protein efficiency ratio were confirmed. These results indicated that coating amino acids with casein improved plasma amino acid balance, probably by altering the absorption and retention times of tryptophan and leucine.

ハマチの栄養要求に関する研究 Ｉ ハマチ用精製基本飼料の検討

In order to establish a basal diet suitable for a nutritional requirement study of yellowtail Seriola quinqueradiata, the nutritive values of two pruified test diets used previously for yellowtail were tested by comparing the effects of the diets on the growth of young yellowtail and on the feed efficiency. The casein (T-diet) and casein gelatin (Y-diet) diets were the test diets. When fed the T-diet, fish in the 10g (average body weight) size group exhibited high growth and the diet produced high feed efficiency. However, fish in the 20g or 40g (average body weight) size group when fed the same diet experienced low growth with high mortalities; the feed efficiency also was low. The fish in the 10g size group fed on the Y-diet exhibited high feed intake, but their growth was quite poor, As a result, the feed efficiency of the Y-diet was extremely low. The low nutritive value of the Y-diet was thought to be attributable to its low pH (4.7). Therefore, the diet was ad-justed to pH 6.7 with 3% sodium hydroxied (Yp-diet). This diet produced high growth of fish and high feed efficiency, and its nutritive value was superior to those of T-diet and Y-diet. From these results, we propose that the Yp-diet (pH about 6.7) composed of 64.2% casein, 13.5% gelatin, 90% pollack liver oil, 7.0% mineral mixture, 3.0% vitamin mixture, 2.3% supple-mental amino acids, and 1.0% attractants can be used as a provisional basal diet for the nutritional study of yellowtails.

Effect of Dietary Quality of Protein on Liver Microsomal Mixed Function Oxidase System, Plasma Cholesterol and Urinary Ascorbic Acid in Rats Fed PCB

Exposure of rat to polychlorinated biphenyls (PCB) results in an increase in activity of liver microsomal mixed function oxidase system, plasma cholesterol and urinary ascorbic acid. Experiments were designed to study the effect of dietary quality of protein on these metabolic responses to dietary addition of PCB. The diets contained either whole egg protein, casein, fish protein, soy protein, soy protein plus 0.34% methionine, wheat-gluten, corn-gluten or gelatin fed at 10% of the diet. In general, the relative biological values of proteins as shown by the gains in body weight were positively correlated with activity of the microsomal enzyme system including aminopyrine N-demethylase, aniline hydroxylase, cytochrome P-450 and NADPH-cytochrome c reductase, plasma level of cholesterol and urinary ascorbic acid. Supplement of methionine to soy protein diet containing PCB caused a significant increase in liver and plasma cholesterol and in urinary ascorbic acid, although the influence on the microsomal enzyme system was slight. The gelatin diet containing PCB gave higher activity of the enzyme system than that expected from the biological value, although the same protein diet without PCB caused quite low activity as expected from the biological value.plasma cholesterol urinary ascorbic acid

Use of crystalline amino acids coated with casein in diets for carp.

Crystalline amino acids coated with casein as a supplement to gelatin or casein and four kind of carbohydrates with different molecular size (glucose, maltose, dextrin and alpha-starch) were fed to fingerling carp for 6 weeks to test a hypothesis that the poor untilization of crystalline amino acids by arp may be due to rapid absorption of certain amino acids. Fish fed with the gelatin diet supplemented with 10 amino acids coated with casein showed comparable growth to that of the control diet (25% casein, 10% gelatin and 30% alpha-starch) with which the fish achieved 378% weight gain in 6 weeks, and more than four-fold faster growth rate and almost two-fold better feed efficiency than the fish fed with the gelatin diet supplemented with the same 10 amino acids but uncoated. There was no significant differences in growth and feed efficiency among fish fed with glucose, maltose, dextrin and alpha- starch. Addition of either coated or uncoated arginine to casein, improved growth and feed effciency, but there was no significant difference between the two groups. These results may indicate that coating amino acids with casein minimized variation in absorption rate of amino acids, which resulted in relatively simultaneous availability of all amino acids to the tissues for optimal protein synthesis. Whereas, differences in absorption rate among glucose, maltose, dextrin and starch may not have shown any significant effect on the growth or feed efficiency, because glucose is the only basic building block of carbohydrates used in this study.

Rat Liver Glutathione: Possible Role as a Reservoir of Cysteine

Rat liver contains a high concentration (7-8mM) of reduced glutathione and its level changes rapidly when starving or feeding rats. We concluded that one of the functions of liver glutathione was to act as a reservoir of cysteine. When starved rats were fed a protein-free diet, the increase in liver glutathione was dependent on the amount of cysteine added to the diet. A cysteine-dependent increase of glutathione was also observed in rats fed a diet containing gelatin with cysteine, but the increase was relatively lowered compared with rats fed a protein-free diet containing the same amount of cysteine. This suppression of the increase in glutathione was observed much more clearly when the gelatin diet was fortified with tryptophan in addition to cysteine. In the presence of tryptophan, L-[35S]-cysteine in the diet appeared to be incorporated primarily into liver and serum proteins, and degradation of liver glutathione must also have been enhanced. Addition of excess cysteine to the diet masked the effects of gelatin and tryptophan, stimulated glutathione synthesis in the liver as well as incorporation of dietary cysteine into protein fractions. Prolonged starvation of rats or injection of dibutyryl-3',5'-cyclic AMP lowered the glutathione level,but the level did not decrease below 2 to 3 mM. These findings suggest that there may be at least two pools of glutathione. A labile fraction, constituting one-third to one-half the total liver glutathione, probably serves as a reservoir of cysteine which can be released by gamma-glutamyl-transferase when necessary.

Vitamin E and stress. 8. Nutritional effects of dietary stress with silver in vitamin E-deficient chicks and rats.

1. When chicks were given a fat-free casein–gelatin diet and, after 2 weeks of age, 0·15% silver acetate in the drinking water, they were found to have colourless exudates mainly in the pectoral region and partly in the peritoneal and pericardial spaces. Vitamin E and selenium, separately and together, failed to prevent this condition. Vitamin E was required together with methionine to prevent the condition. Methionine itself induced green staining of a few of the exudates.2. When lard was added to the casein–gelatin diet and the chicks were also given Ag, some green exudates were found in addition to the colourless ones. Addition of vitamin E or Se or both prevented the green exudates, but raised the incidence of colourless exudates. Methionine enhanced the green exudate condition, but again when combined with vitamin E prevented both types of exudate.3. A similar condition characterized by colourless exudates was induced by giving chicks diets based upon gelatin, yeast BPC, α-protein (with extra salts) or α-protein with gelatin. A torula yeast diet induced green exudates and haemorrhages.4. All the basal diets, which were deficient in sulphur amino acids, produced dystrophy of the breast muscle. Four of these diets contained no fat. Some diets also induced dystrophy of the gizzard. Vitamin E and Se protected against both these lesions. Methionine was protective in all except the torula yeast diet.5. Ethionine induced muscular dystrophy in chicks given a vitamin E-deficient diet adequate in sulphur amino acids. Additional methionine or vitamin E was protective, but cystine was not. Ethionine also produced a small incidence of green exudates and slight haemorrhages. This condition was prevented by vitamin E but not by methionine. The liver damage due to ethionine was not prevented by vitamin E, methionine or cystine.6. Liver necrosis was induced in rats by giving them an 8·3% casein diet and Ag, 130–1000 ppm, in the drinking water or the diet. Necrosis was produced even in the absence of dietary fat. Vitamin E and DPPD (N,N′-diphenyl-p-phenylenediamine) prevented necrosis, but adenine sulphate (0·25%), methionine (0·15%) and IONOX 330 (2,4,6-tri-(3′,5′-di-tert.-butyl-4′-hydroxybenzyl) mesitylene) did not. Se, 0·05 ppm, protected against 130 ppm Ag, but 1000 ppm Ag overcame the protective effect of 1 ppm Se. Similarly, 3 ppm cyanocobalamin was partly protective against 130 ppm Ag, but not against the higher concentration. Gold chloride (1000 ppm Au) had a mildly necrotic effect against which vitamin E did not protect. Neither copper sulphate (500 ppm Cu) not arsanilic acid (70 ppm As) induced liver necrosis.7. A high intake of Se (20 ppm as sodium selenate) was necrogenic in rats given a 10% casein diet; vitamin E and methionine did not protect. Vitamin E and cystine raised the low incidence of an exudative condition found in rats given 20 ppm Se. Methionine opposed this action of vitamin E.8. It was concluded that exudative diathesis in chicks could be resolved into a simple exudative condition and a superimposed haemorrhagic condition. Ag is a pro-exudative factor. Vitamin E and Se are also pro-exudative for chicks given the casein–gelatin–lard–Ag treatment. Torula yeast, methionine, lard, Ag (with lard) and ethionine are all pro-haemorrhagic factors. Se and Ag have an antagonistic relationship in rats and chicks; in chicks, however, Se synergizes with Ag when the supply of methionine is limited.

The Amino Acid Deficiencies of Gelatin for the Growing Chicken

EARLY attempts by Jackson et al. (1928) and Kruse et al. (1934) to promote optimal growth in rats fed gelatin-containing diets supplemented with the amino acids then known (1928–34) to be deficient failed. At that time, however, threonine had not been identified as an essential amino acid. Even in the light of newer knowledge a decade later, Hier et al. (1944) were still unsuccessful in obtaining good growth in rats fed amino acid-supplemented gelatin diets. These workers reported slower growth on the amino acid-supplemented gelatin diets than for the amino acids fed separately. They concluded that the difficulty with gelatin might be due to an inhibitory effect caused by the unusually high content of glycine and proline. Fourteen years later Summers and Fisher (1962) again tried, unsuccessfully, to simulate the amino acid pattern and the growth response of isolated soy-protein in chicks fed amino acid-supplemented gelatin diets. In these …