J. C. Rogler

Herbivore growth reduction by tannins: Use of waldbauer ratio techniques and manipulation of salivary protein production to elucidate mechanisms of action

Abstract The consumption and utilization of food by rats fed diets both high and low in condensed tannin was analysed on a dry weight basis and on a Kjeldahl nitrogen basis. Growth analyses followed the protocol devised for insects by Waldbauer. The hypothesis that tannin-induced proline-rich salivary proteins (PRPs) diminish the antinutritional effects of dietary polyphenolics in mammals was investigated by supplementing diets with 0.05% propranolol to suppress PRP production. Rats fed diets high in tannin gained less weight than those fed low tannin diets. This effect was too pronounced to be explained by differences in feed consumption and could only be attributed to depressed efficiency in converting injested food to body matter. The reduction in approximate digestibility (AD) with high tannin sorghum diets was low relative to the severe reduction in the conversion of digested food into body matter (ECD) for high tannin diets. The main growth reducing effect of tannin thus appears to have been on the post-absorptive utilization of nutrients rather than on the digestibility of the diet. On a nitrogen basis, AD(N) is reduced in the presence of tannins so tannins did act preferentially on the digestion and absorption of nitrogen. Nevertheless, on a nitrogen basis ECD(N) was even more substantially depressed by tannins and so it could not be concluded that tannins act only or even mainly as digestibility-reducing agents. Propranolol only produced adverse effects in combination with tannin but these were much more severe than those with tannin alone. Further evidence suggested that the cause was the suppression of PRP production. PRPs are known to bind to tannins in competition with other proteins and their absence denies the animal the means to neutralize dietary tannin. This study also examines the effect of sodium chloride (0.5%) in the diet following a previous report that salt alleviates the effect of dietary tannins in mice. In our experiments this had negligible effects. We conclude by comparing our data for a mammal to previous studies on insects using these same parameters to assess consumption and utilization of foods.

The effects of copper on collagen cross-linking.

Abstract Evidence in this report indicates that copper is directly involved in the process of collagen cross-linking. The bones from chicks fed copper-deficient diets became brittle and fragile. The collagen in copper-deficient bone was more easily extracted and contained less total aldehyde than corresponding controls. After chromatography on CM-cellulose columns and acrylamide gel electrophoresis, monomer or α-collagen and the cross-linked dimer, β-collagens, could be separated and quantitated. The α to β ratio of collagen from copper-deficient bone was approximately twice that of collagen from control bone, indicating a decrease in the cross-linking.

Growth reduction by dietary tannins: Different effects due to different tannins

Abstract The effects of different tannins were compared in feeding trials utilizing rats fed diets that were equal in their total phenolics content. The drug propranolol was used to suppress proline-rich salivary protein production in some animals in order to examine the defensive potential of these proteins against dietary tannins. Differences were evident in the way different tannins affected digestion and the post-digestive assimilation of nutrients into new body mass. Different tannins also interacted differently with propranolol and were recovered in fecal material in different quantities. While the two condensed tannin-containing diets and one hydrolysable tannin-containing diet each had similar effects on overall weight gain, they appeared to cause their effects in different ways. These results are discussed in the context of the frequently made assumption that all tannins act as feeding deterrent allelochemicals in a uniform manner.

Effects of Sorghum Grain Tannins and Dietary Protein on the Activity of Liver UDP-Glucuronyltransferase

Abstract The activity of liver microsomal UDP-glucuronyltransferase (EC 2.4.1.17), an enzyme known to detoxify phenolic compounds, was measured in chicks and rats fed high- (HTS) and low-tannin sorghums (LTS). In an initial investigation, activity was significantly elevated in chicks fed HTS-soybean meal diets over those fed the LTS control diet. Other studies were designed to differentiate between the effects due to tannin and those resulting from a protein deficiency which had previously been reported to increase the activity of this enzyme. In general, only a relatively small part of the increased activity observed by feeding HTS to chicks could be attributed to a tannin-induced protein deficiency. The same phenomenon of elevated activity produced by feeding HTS to chicks was not observed in the rat. These results would suggest that sorghum tannins, or their breakdown products, are absorbed and activating UDP-glucuronyltransferase in the chick, but not the rat.

Genetic analysis of a population of Tribolium. I. Corn oil sensitivity and selection response.

IN most quantitative genetic studies the hypothesis of polygenic inheritance and random environmental effects is plausible. However, in one of several populations of Tribolium castaneum developed by Yamada and Bell (1963) to study the effectiveness of selection for growth in different environments this hypothesis was not satisfactory. The selection response in this particular population suggested a peculiar genotype by environment interaction. Although the situation was confirmed by biometrical analyses, these techniques did not suffice to answer questions concerning the underlying genetic mechanism on which selection had acted. It was our objective to identify the genetic basis of this peculiar response to selection and consequently more precisely define genotypes and genotypic differences. A preliminary report of this work was given by Costantino et al. (1966).

Dietary self-selection and the regulation of protein and energy intake in chicks

Studies were conducted to determine whether chicks could regulate their protein intake independent of total energy intake in self-selection feeding trials. Day-old White Mountain cockerels were reared in electrically-heated battery brooders and given access to either a 23% protein control ration (no choice) or two diets containing 10% or 60% protein with or without supplemental amino acids. The latter were added to either improve the dietary amino acid balance or to alter plasma and brain levels of free large neutral amino acids (tryptophan, isoleucine, leucine, valine, phenylalanine, and tyrosine) which have been implicated in the neuroregulation of feed intake. Both feed and water were provided ad lib, and the location of the feed troughs within each pen were changed daily. Body weights and feed intakes were measured daily, and total calorie and protein intakes were calculated. Chicks offered 10% and 60% protein diets with no supplemental amino acids exhibited reduced weight gains and markedly higher protein intakes as compared to birds fed either the control ration or those given a choice between 10% and 60% protein diets supplemented with methionine. The higher protein consumption by chicks fed the unsupplemented diets most likely was a result of an attempt to compensate for a dietary methionine deficiency. Chicks fed the 10% and 60% protein diets supplemented with amino acids grew at a slower rate than those fed the 23% protein control diet. In general, plasma and brain data did not support a proposed relationship between certain large neutral amino acid ratios and protein or energy intake.

Genetic analysis of a population of Tribolium. II. Metabolic pattern of corn oil sensitive anomaly.

IN earlier papers (Costantino et al., 1966, 1967), two properties of a unique population of Tribolium castaneum were established. Firstly, corn (maize) oil inhibits larval growth and the degree of inhibition is a function of the concentration of corn oil in the diet; and secondly, the genetic basis of this inhibition is an autosomal recessive gene. Furthermore, these two properties accounted for certain unexpected phenotypic changes observed in the growth characteristics of this population during a long-term selection study. Our attention is now focused on (1) describing the mutant phenotype, and (2) elucidating the biological mechanism(s) responsible for the populations response to corn oil.

The Effect of Magnesium and Fluoride on Bone Pyrophosphatase Activity

Summary The addition of Mg ions to bone homogenates stimulated pyrophosphatase activity in the absence of F ions, but inhibited pyrophosphatase activity in the presence of F ions. However, femur pyrophosphatase levels were increased in chicks fed diets containing high levels of both Mg and F for 3 or 6 days as compared with chicks fed diets containing identical levels of either element alone.

Observations on a magnesium-fluoride interrelationship in chicks.

The addition of high levels of both magnesium and fluoride to either practical or semipurified diets complete in all known nutrients produced the following results in young chicks: (1) greater reduction in growth than with either magnesium or fluoride alone; (2) the development of a characteristic leg weakness; (3) decreased calcification of the bone. Increasing the calcium level in the diets from 1.0 to 1.5% reduced but did not prevent the magnesium-fluoride relationship. The growth reduction, leg weakness and reduced bone ash caused by high dietary magnesium and fluoride were obtained only when one-day-old chicks were fed the experimental diets; these results were not observed when chicks at two weeks of age were fed the same diets, nor could the interaction be shown in weanling rats. Plasma alkaline phosphatase activity in chicks was elevated about twofold by added fluoride regardless of the dietary magnesium or calcium levels. The level of alkaline phosphatase in the plasma decreased with age in all groups at approximately the same rate. Dietary magnesium or fluoride levels did not influence the conversion of 3-phosphoglycerate to phosphoenolpyruvate by muscle homogenates. 11 references, 4 tables.

The partial characterization of an amine oxidase in bone tissue.

Summary Evidence is presented which demonstrates that chick bone contains an amine oxidase which could function in the oxidative deamination of collagen lysyl residues to α-amino adipic acid-Δ-semialdehyde residues. This function would be directly related to the process of collagen cross-linking. The enzyme was slightly soluble, had an apparent molecular weight from gel filtration studies of 250,000, and could be partially purified by ammonium sulfate precipitation. When benzylamine was used as the substrate in kinetic studies, a K mapp of 0.15 mM was obtained. The enzyme required copper and pyridoxal phosphate and was competitively inhibited by beta-amino propionitrile, butylamine, and the peptide, lysine-vasopressin. Benzylamine oxidation was noncompetively inhibited by ascorbic acid, penicillamine, and isoniazid. The lysine in lysine-vasopressin was oxidized to the semial-dehyde. The pH optimum for oxidations was approximately pH 7.7.