Diet Of Mammals Research Articles

Dental microwear features as an indicator for plant food in early hominids: A preliminary study of enamel

Studies of dental microwear have shown qualitative and quantitative differences related with specific diets of mammals. Here we report a classification of the features of microwear and the results of a comparative study of the characteristics of wear produced by plant food. Species which are mainly folivorous or herbivorous show common features useful for providing information about the diet of early hominids at Garusi and Laetoli (Tanzania), Hadar (Ethiopia) and Olduvai (Tanzania).

The essential nature of linoleic acid in mammals

Linoleic acid [CH 3(CH 2) 4(CH = CHCH 2) 2(CH 2) 6 COOH] is a precursor of the icosanoids −20-carbon fatty acids which include leukotrienes, prostaglandins, thromboxanes and related compounds. Until recently, the classical symptoms resulting from deficiency of linoleic and other essential fatty acids (EFAs) have been unexplained. Recently, however, the finding that linoleic acid is an important constituent of epidermal sphingolipids has suggested a biochemical mechanism for some of the EFA-deficiency skin symptoms and has indicated why linoleic acid is an essential component of the mammalian diet.

Food Habits of Microtus, Peromyscus, and Blarina along Kansas Roadsides: Cause for Caution in Roadside Contamination Studies

Food Habits of Microtus, Peromyscus, and Blarina along Kansas Roadsides: Cause for Caution in Roadside Contamination Studies

Alimentary tract measurements as indicators of diets of small mammals

Alimentary tract measurements as indicators of diets of small mammals

Blood-brain transfer of galactose in experimental galactosemia, with special reference to the competitive interaction between galactose and glucose.

The interaction between glucose and galactose during transport across the cerebral capillary endothelium was studied in anesthetized rats. Although galactose is present in the diet of suckling mammals and is a potential substrate for brain metabolism in adult mammals, its effect on glucose transport in adult rats is unknown. A kinetic model was formulated to analyze the effect of chronically elevated galactose levels on glucose transport in adult rats. The analysis indicated that galactose and glucose compete for the same transport mechanism in the cerebral capillary endothelium. The Tmax of glucose and galactose were both about 380 mumol 100 g-1 min-1 and the Kt of galactose (30 mM) was about three times that of glucose (10 mM). During prolonged galactosemia in adult rats, neither the Tmax, nor the Kt of either competitor changed substantially when compared with rats subjected to acute galactosemia. At 10 mM galactose in plasma in rats with acute galactosemia, the inhibition of glucose transport, simulated a 25% reduction of plasma glucose, and in rats with chronic galactosemia a 20% reduction. This moderate effect is in contrast to the effect of galactose in suckling rats in which 10 mM galactose in plasma reduced the glucose transport to a level corresponding to a 50% reduction of the plasma glucose concentration.

Habitat utilisation and the prey taken by Kestrels in arable fenland

These Kestrels made 70% of their strikes over grass which comprised only 17% of the study area. This reflected their mainly mammalian diet.

Comparison of frugivory by howling monkeys (Alouatta palliata) and bats (Artibeus jamaicensis) in the tropical rain forest of Los Tuxtlas, Mexico.

Information on the fruit diets of howling monkeys and fruit-eating bats in the tropical rain forest of Los Tuxtlas, Mexico was collected for a year to compare the plant species used. Howling monkeys used 19 plant species whereas bats used 32 plant species as fruit sources. Eleven species were common in the diet of both mammals. A rank analysis at the plant species level showed that the fruit diets of Alouatta and Artibeus were very different. In contrast to bats, howling monkeys displayed a seasonal pattern in fruit consumption. Diet overlap between the two mammals was highest during the monkeys' fruit-eating season. Measures of fruit production in eight trees (four species) indicated marked variations in fruit biomass produced and in length of fruiting from tree to tree and species to species. Peaks in fruit production were typical both at the species and the individual tree levels, demonstrating the very patchy nature of the fruit available to the monkeys and the bats.

The significance of cusps.

It has been argued that the prolonged retention of cusps in the human dentition is a relatively recent aberration due to the negligible abrasiveness of modern diets and that to achieve maximum efficiency and freedom from disease human teeth should be worn down as they are in many herbivorous mammals. Here we critically review the evidence that has been put forward to support this idea and, after discussing the design of occlusal surfaces in relation to the wide variety of mammalian diets, we conclude that cusps are adaptations for breaking food with specific physical properties.

Diets of Pliocene mammals from Omo, Ethiopia, deduced from carbon isotopic ratios in tooth apatite

Carbon isotopic ratios in tooth apatite of Pliocene fossil mammals from Omo, Ethiopia, dated at 2.0 m.y. ago reported here are consistent with dietary predictions based on modern herbivores of the African savannah. The results indicate the applicability of the technique in reconstructing dietary patterns of fossil animals including hominids.

The Microhistological Technique: Testing Two Central Assumptions in South-Central New Mexico

Analysis of the botanical content of diets of livestock, big game, small mammals, and insects has become common in research. The better known dietary analyses utilize either stomach, fecal or esophageal fistula samples. The respective advantages and disadvantages of these procedures have been recognized, and the use of a particular procedure is dictated by the type of study, subject animal, available facilities, time, manpower, and information desired. Methods for quantifying the diet sample obtained by an analytical procedure have been generalized as visual appraisal, manual separation, microhistological techniques, and microscope point techniques (I’heurer et al. 1976). Of these general categories, visual appraisal and manual separation are limited by the ability of the researcher to quantify individual species in the sample diet. Hence, these methods may contain large inherent personal errors. The microscope point techniques require statistical regression procedures, determination of species weight/volume relationships, and overestimation correction tactors. The microhistological techniques have become the most favored method. Sparks and Malechek (1968) have outlined the basic procedure for this method. However, its accuracy in determining dry-weight composition of masticated forage samples was not examined. The objective of this study was to examine two central assumptions of the microhistological technique and determine if these assumptions were satisfied when determining dry-weight composition of masticated forage samples from blue grama (Bouteloua grucilis) foothill mngeland. These assumptions were that percent frequency can be used to estimate particle density and the percent of identifiable material is constant for each species. Methods Samples were collected from esophageal-fistulated steers grazing native shortgrass rangeland in south-central New Mexico. The study area was located on the Fort Stanton Experimental Ranch. The blue grama-dominated rangeland has been described by Allison et al. ( 1977). Dietary sampling was conducted during 1975 and 1976. Three periods representing three different plant growth stages+arly summer, late summer, and mid winter-were selected for study. Handling and slide preparation of sample material as well as calculations for frequency, particle density, relative density, and percent dry-weight followed the procedure outlined by Sparks and Malechek (1968). Five slides were prepared for each sample period, and 20 systematically located fields were sampled for particle frequency and density on each slide to give 100 fields for each period. Reference material for all species present was collected during late summer. Reference slides, drawings, and photographs were utilized in identifying species within sample diets. When a particle observed in a field could not be identified, the slide was moved so that identification was improved by observing the entire particle.

Evidence that pancreatic lipase is responsible for the hydrolysis of cutin, a biopolyester present in mammalian diet, and the role of bile salt and colipase in this hydrolysis

The enzyme, which catalyzes hydrolysis of cutin, an insoluble biopolyester of hydroxy and epoxy fatty acids, was purified from porcine pancreas. With three different purification methods, previously used for the purification of pancreatic lipase, it is shown that cutin hydrolase is pancreatic lipase. This enzyme released oligomers and all types of monomers from the polymer with a pH optimum around 7.5. Taurodeoxycholate inhibited cutin hydrolysis by lipase and colipase reversed this inhibition. Evidence is presented which suggests that bile salt stabilizes the enzyme at the surface of the insoluble substrate and that the interaction of the polymer surface with the lipase-colipase-bile salt system is similar to that previously observed with triglycerides. Diethyl- p-nitrophenyl phosphate inhibited cutin hydrolysis by lipase but the hydrolysis was insensitive to diisopropyl fluorophosphate.

Protein nutrition of Tenebrio molitor L. XVI. Effects of dietary protein concentration on larvae of race F.

The optimal concentration of dietary protein for larvae of Tenebvio molitor, race F, Gembloux strain, has been the subject of various investigations. When casein provided the protein in the diet, the optimal level was between 2 or 3 and 20 % in one case (LECLERCQ & LOPEZ-FRANCOS, 1964) and 20 % in another (DAVIS, 1970). The difference in concentrations apparently was linked to the amino acid compositions of the caseins used in these investigations. When six oilseed meals provided the dietary protein for larvae of T. molitor, better growth was obtained with 10 % than with 3 % of dietary protein (DAVIS & SOSULSKI, 1972). Because comparative nutrition investigations are in progress using larvae of T. molitor and mice or rats, the question of optimal protein concentration in larval diets has again been posed. The mammalian diets regularly contain 10 % of protein; however, this amount of protein cannot be chosen arbitrarily as optimal for larvae of T. molitor. The present paper reports the effect on growth of larvae of T. molitor of graded concentrations of dietary protein from 1 to 32 %, provided by autoclaved protein isolate of soybean.

Diets of large mammals in the woodlands around Lake Kariba, Rhodesia.

Large mammals that formerly occupied the Kariba basin of the Middle Zambezi Valley have, since it was flooded, been forced to live in a restricted range of deciduous woodland habitats. Feeding records in a study area on the shore of Lake Kariba showed that most herbivore species were browsers, and that only the tree components of their diets varied significantly between vegetation types. The common species varied a proportion of their diet seasonally. However, each depended upon a small range of food staples which differed from those of other species and acted as food refuges for part of the year. Diets overlapped during the wet season because of diversification, and in the late dry season because of common use of a restricted range of plants remaining green. There was a good correlation between the ability of a species to avoid dietary overlap and its biomass in the study area. The chance of interspecific competition occurring increased in the late dry season when most of the species would formerly have migrated from the study area to the flood plain. Despite the enforced occupation of only part of their former annual range the more common herbivores maintained a considerable degree of ecological separation through utilisation of different foods.

Requirement of essential fatty acids and avian atherosclerosis.

ALTHOUGH Reiser in 19501 claimed that chickens needed a source of essential fatty acids during growth, the same author later concluded2 that mature hens, maintained for a full year on a fat-free diet, did not require essential fatty acids for egg production or hatchability. More recently Bieri et al.3,4 showed that chicks could be grown to maturity on an essentially fat-free ration without marked deficiency symptoms and suggested that Reiser's purified chick ration may have been deficient in thiamine and vitamin A. In contrast with the chicken, exclusion of essential fatty acids from the diet of several mammals leads to a clear deficiency disease which, among more apparent external symptoms, is also characterized by an increase in liver and epidermal cholesterol and a decrease in serum cholesterol in the rat5, and by aortic lesions in the pig6. Such observations lend support to the view of a possible connexion between deficiency of essential fatty acid and atherosclerosis7. Since atherosclerosis develops in the chicken on low-fat as well as on normal rations8, it seemed of interest to determine if rigid exclusion of essential fatty acid from the diet would aggravate aortic lesions. At the same time more information regarding the requirement of essential fatty acids and deficiency symptoms would be obtained from a group of birds maintained continuously on a diet deficient in essential fatty acids from the day of hatching until 19 months of age.

THE BIOLOGY OF TSETSE FLIES

THE BIOLOGY OF TSETSE FLIES