Effects of prey size, meal size, meal composition, and daily frequency of feeding on the recovery of rodent remains from carnivore scats

1997 ◽  
Vol 75 (11) ◽  
pp. 1811-1817 ◽  
Author(s):  
Brian T. Kelly ◽  
Edward O. Garton
Keyword(s):  
Prey Size ◽  
Energy Content ◽  
Meal Size ◽  
Correction Factors ◽  
Physiological Mechanisms ◽  
Scat Analysis ◽  
Gastrointestinal Physiology ◽  
Daily Frequency ◽  
Feeding Trials ◽  
Meal Composition

Recovery of rodent bone and teeth from coyote (Canis latrans) scats (feces) varied with prey size, meal size, energy content of the meal, and the frequency with which prey were consumed. Mean percentages of mouse and rat teeth recovered ranged from 1% (SE = 0.5%, n = 5) to 24.4% (SE = 3.6%, n = 4) and from 13.8% (SE = 3.8%, n = 5) to 52.5% (SE = 16.6%, n = 5), respectively. A significant portion of this variation resulted from physiological mechanisms affecting how long prey were retained in the digestive acids of the stomach. Recovery of hair did not vary and thus it was considered to be nondigestible. Owing to the variation in the recovery of bone and teeth and the lack of variation in the recovery of hair, we recommend the use of teeth or bone to identify the small rodents present in carnivore scats, and then the use of a visual estimate of hair, or sample of hair, to apportion the scat to the prey items present. We caution against using the numbers of teeth or diagnostic bones to determine the number or amount of a prey item represented by a scat without addressing the variability in their recovery. The effects of gastrointestinal physiology should be considered when planning feeding trials to derive correction factors for scat analysis.

Digestible energy of wheat and oat grains when fed to sheep

1971 ◽  
Vol 11 (53) ◽  
pp. 610 ◽  
Author(s):  
MC Nottle
Keyword(s):  
Organic Matter ◽  
Dry Matter ◽  
Energy Content ◽  
The Body ◽  
Wheat Grain ◽  
Crude Fibre ◽  
Digestible Energy ◽  
Dry Matter Digestibility ◽  
Gross Energy ◽  
Feeding Trials

In pen feeding trials with eight Merino wethers, digestion coefficients were estimated for rations of cereal chaff-wheat grain-oat grain mixture, and wheat grain and oat grain fed separately at two levels of intake. Digestion coefficients for wheat and oat grain fed at 675 g/day in a double crossover experiment were dry matter 89.4, 80.8 per cent, organic matter 90.1, 82.6 per cent, protein 82.3, 77.6 per cent, ether extract 84.1, 90.9 per cent, crude fibre 33.2, 59.9 per cent, nitrogen free extractives 93.2, 85.8 per cent, energy 88.1, 81.0 per cent, total digestible nutrients 91.6, 87.1 per cent, and starch equivalents 90.7, 85.7. When these grains were fed at 785 g/day there was about 10 per cent improvement in crude fibre digestibility for both grains and 1-2 per cent improvement for other estimations with oats but not with wheat. The gross energy content of the wheat and oat grains when fed at 675 g/day was 4407 and 4700 calories/g dry matter. The digestible energy of the wheat in calories/g dry matter and organic matter was 3869 � 30, 3933 � 30 and for oats 3791 � 59, 3910 � 61. When fed at 785 g/day these values for wheat were 3850 � 50,3911 � 51 and for oats 3796 � 34, 3913 � 51. A highly significant relationship was found between energy and dry matter digestibility which for wheat diets was Y = 1.074x 7.840. r = 0.993 (P<0.001), and for oats and the mixed diet of cereal chaff-oat grain-wheat grain, Y = 0.983x + 1.550. r = 0.996 (P<0.001) where Y = energy and X = dry matter digestibility and r = the coefficient of correlation. Because of the similar digestible energy content of, and the body weight gains of sheep on, these two grains it was concluded that under the present conditions these grains were equivalent weight for weight.

Prey selection by harbour seals, Phoca vitulina, in relation to variations in prey abundance

1997 ◽  
Vol 75 (9) ◽  
pp. 1508-1518 ◽  
Author(s):  
Dominic J. Tollit ◽  
Paul M. Thompson ◽  
Simon P. R. Greenstreet
Keyword(s):  
Diet Composition ◽  
Prey Size ◽  
Prey Selection ◽  
Phoca Vitulina ◽  
Correction Factors ◽  
Fish Prey ◽  
Size Selection ◽  
Harbour Seals ◽  
Moray Firth ◽  
Time Periods

This study compared the composition of the diet of harbour seals (Phoca vitulina) feeding in the Moray Firth, Scotland, with the abundance of their fish prey estimated from dedicated fishery surveys in January 1992 and 1994 and June 1992. Prey-size selection was also examined in these three time periods and in January 1991. In each period, the most abundant fish species contributed most to the diet. However, the relative abundances of the remaining species in the sea showed little similarity to their contribution to the seals' diet. Diet composition was almost totally dominated by either pelagic species or species dwelling on or strongly associated with the seabed, depending upon the relative abundance of pelagic schooling prey. Most fish consumed were 10–16 cm in length, although larger cod and herring were taken. With the exception of cod, the extent of size selection was dependent upon the use of correction factors that accounted for otolith erosion due to digestion.

scholarly journals Thermic effect of food in man: Effect of meal composition, and energy content

1990 ◽  
Vol 64 (1) ◽  
pp. 37-44 ◽  
Author(s):  
J. L. Kinabo ◽  
J. V. G. A. Durnin
Keyword(s):  
Metabolic Rate ◽  
Energy Content ◽  
Open Circuit ◽  
Obese Female ◽  
Thermic Effect Of Food ◽  
Low Carbohydrate ◽  
Douglas Bag ◽  
Effect Of Food ◽  
Thermic Effect ◽  
Meal Composition

The effect of meal composition and energy content on the thermic effect of food (TEF) was investigated in sixteen adult, non–obese female subjects. Each subject consumed four different test meals, each meal on a different day. Meals were of high-carbohydrate-low-fat (HCLF) with 0.70, 0.19 and o.11 of the energy content from carbohydrate, fat and protein respectively, and low-carbohydrate-high–fat (LCHF) with 0.24, 0.65 and 0.11 of the energy content from carbohydrate, fat and protein respectively. The energy contents of the test meals for each composition were 2520 kJ (600 kcal) and 5040 kJ (1200 kcal). The basal metabolic rate (BMR) and the postprandial metabolic rate (PP-MR) were measured by open-circuit indirect calorimetry using the Douglas bag technique while the subjects were in the supine position. The mean BMR value was 3.63 (SE 0.07) kJ/min (0.87 kcal/min (SE 0.17)). The 5 H-TEF value for the 2520 kJ (600 kcal) HCLF meal was 228 (SE 11.8) kJ (54 kcal (SE 2.8)) and for the LCHF meal was 228 (SE 9.6) kJ (54 kcal (SE 2.3)). The corresponding values for the 5040 kJ (1200 kcal) meals were 356 (SE 20.4) kJ (85 kcal (SE 4.9)) and 340 (SE 15.8) kJ (81 kcal (SE 3.8)). There was no significant (P =0.49) effect of meal composition on TEF, but the energy content of the meals had a significant (P < 0.001) effect on TEF. In all subjects and for all meals, PP-MR had not returned to premeal level 5 h after a meal, indicating that the TEF values measured underestimate total TFF. The present study suggests that TEF is significantly influenced by the energy content of a meal but not by meal composition.

scholarly journals Effects of Prey Size on Scat Analysis to Determine River OtterLontra canadensisDiet

2009 ◽  
Vol 15 (4) ◽  
pp. 449-453 ◽  
Author(s):  
Shawn M. Crimmins ◽  
Nathan M. Roberts ◽  
David A. Hamilton
Keyword(s):  
Prey Size ◽  
Scat Analysis

scholarly journals Face Validity of Observed Meal Patterns Reported with 7-Day Diet Diaries in a Large Population-Based Cohort Using Diurnal Variation in Concentration Biomarkers of Dietary Intake

Nutrients ◽  
2022 ◽  
Vol 14 (2) ◽  
pp. 238
Author(s):  
Marleen A. H. Lentjes ◽  
Linda M. Oude Griep ◽  
Angela A. Mulligan ◽  
Scott Montgomery ◽  
Nick J. Wareham ◽  
...  
Keyword(s):  
Diurnal Variation ◽  
Blood Sample ◽  
Energy Content ◽  
Large Population ◽  
Population Based ◽  
Sampling Time ◽  
Meal Size ◽  
Face Validity ◽  
Sample Collection ◽  
Meal Patterns

In a cross-sectional analysis of a population-based cohort (United Kingdom, N = 21,318, 1993–1998), we studied how associations between meal patterns and non-fasting triglyceride and glucose concentrations were influenced by the hour of day at which the blood sample was collected to ascertain face validity of reported meal patterns, as well as the influence of reporting bias (assessed using formula of energy expenditure) on this association. Meal size (i.e., reported energy content), mealtime and meal frequency were reported using pre-structured 7-day diet diaries. In ANCOVA, sex-specific means of biomarker concentrations were calculated by hour of blood sample collection for quartiles of reported energy intake at breakfast, lunch and dinner (meal size). Significant interactions were observed between breakfast size, sampling time and triglyceride concentrations and between lunch size, sampling time and triglyceride, as well as glucose concentrations. Those skipping breakfast had the lowest triglyceride concentrations in the morning and those skipping lunch had the lowest triglyceride and glucose concentrations in the afternoon, especially among acceptable energy reporters. Eating and drinking occasion frequency was weakly associated with glucose concentrations in women and positively associated with triglyceride concentrations in both sexes; stronger associations were observed for larger vs. smaller meals and among acceptable energy reporters. Associations between meal patterns and concentration biomarkers can be observed when accounting for diurnal variation and underreporting. These findings support the use of 7-day diet diaries for studying associations between meal patterns and health.

Impact of diet-index selection and the digestion of prey hard remains on determining the diet of the Steller sea lion (Eumetopias jubatus)

2007 ◽  
Vol 85 (1) ◽  
pp. 1-15 ◽  
Author(s):  
D.J. Tollit ◽  
S.G. Heaslip ◽  
R.L. Barrick ◽  
A.W. Trites
Keyword(s):  
Single Species ◽  
Pacific Herring ◽  
Correction Factors ◽  
Eumetopias Jubatus ◽  
Sea Lion ◽  
Recovery Rates ◽  
Sea Lions ◽  
Interspecific Differences ◽  
Feeding Trials ◽  
Better Than

Nine prey species (n = 7431) were fed to four captive female Steller sea lions ( Eumetopias jubatus (Schreber, 1776)) in 11 feeding trials over 75 days to investigate the effectiveness of different methods used to determine diet from prey hard remains. Trials aimed to replicate short (1–2 days) and long feeding bouts, and consisted of single species and mixed daily diets. Overall, 25.2% ± 22.2% (mean ± SD, range 0%–83%) otoliths were recovered, but recovery rates varied by species (ANOVA, P = 0.01) and were linearly related to otolith robustness (R2 = 0.88). Squid beaks were recovered at higher frequencies (mean 96%) than the otoliths of all species. Enumerating both non-otolith skeletal structures and otoliths (together termed bones) increased species recovery rates by twofold, on average (P < 0.001), with increases up to 2.5 times for Pacific herring ( Clupea pallasii Valenciennes in Cuvier and Valenciennes, 1847) and 3–4 times for salmonids. Using bones reduced interspecific differences (P = 0.08), but recovery varied among sea lions. Bones were distributed over more scats per meal (mean 2.9 scats, range 0–5) than otoliths (mean 1.9 scats, range 0–4). In three different 15-day mixed diet trials, biomass reconstruction (BR) indices performed better than frequency of occurrence indices in predicting diet fed. Applying our experimentally derived numerical correction factors (to account for species differences in complete prey digestion) further improved BR estimates, resulting in all 12 unweighted comparisons within 5% (for otoliths) and 12% (for bones) of the actual diet fed.

scholarly journals The control of meal size in human subjects: a role for expected satiety, expected satiation and premeal planning

2011 ◽  
Vol 70 (2) ◽  
pp. 155-161 ◽  
Author(s):  
Jeffrey M. Brunstrom
Keyword(s):  
Energy Expenditure ◽  
Energy Content ◽  
Human Subjects ◽  
Portion Size ◽  
Meal Size ◽  
General Tendency ◽  
Discrete Events ◽  
Expected Satiety ◽  
Psychological Events ◽  
Prevailing View

Unlike energy expenditure, energy intake occurs during discrete events: snacks and meals. The prevailing view is that meal size is governed by physiological and psychological events that promote satiation towards the end of a meal. This review explores an alternative and perhaps controversial proposition. Specifically that satiation plays a secondary role, and that meal size (kJ) is controlled by decisions about portion size, before a meal begins. Recently, techniques have been developed that enable us to quantify ‘expected satiation’ and ‘expected satiety’ (respectively, the fullness and the respite from hunger that foods are expected to confer). When compared on a kJ-for-kJ basis, these expectations differ markedly across foods. Moreover, in self-selected meals, these measures are remarkably good predictors of the energy content of food that ends up on our plate, even more important than palatability. Expected satiation and expected satiety are influenced by the physical characteristics of a food (e.g. perceived volume). However, they are also learned. Indeed, there is now mounting evidence for ‘expected-satiation drift’, a general tendency for a food to have higher expected satiation as it increases in familiarity. Together, these findings show that important elements of control (discrimination and learning/adaptation) are clearly evident in plans around portion size. Since most meals are eaten in their entirety, understanding the nature of these controls should be given high priority.

Selective Predation by Drift-Feeding Brown Trout (Salmo trutta)

1979 ◽  
Vol 36 (4) ◽  
pp. 392-403 ◽  
Author(s):  
Neil H. Ringler
Keyword(s):  
Brown Trout ◽  
Salmo Trutta ◽  
Prey Size ◽  
Energy Content ◽  
Feeding Strategy ◽  
Invertebrate Drift ◽  
Selective Predation ◽  
Heterogeneous Distribution ◽  
Brown Trout Salmo Trutta ◽  
Dominant Characteristic

Consumption of three species of prey by brown trout (Salmo trutta) in a laboratory stream was studied during 7-d experiments. Two drift rates (5 and 10 organisms/min) and three ratios (1:1, 2:1, 5:1) of small:large alternative prey were employed. Responses to prey species stabilized after 4–6 d and 800–1200 prey captures, but no prey was completely excluded from the diet. Size-selective predation was a dominant characteristic of the response. The fish appeared to alter the area (depth) searched in response to prey density; electivity was greatest when prey densities were high. Disproportionate predation on abundant prey ("switching") was a temporary phenomenon, which may have been masked by prey size. Brown trout ultimately achieved 54–91% of a hypothetical diet in which prey are ranked in order of size (energy content). Deviations from an optimal diet may be explained in terms of a feeding strategy that deals with heterogeneous distribution of prey, as well as with the behavioral capabilities of the predator. Key words: behavior, fish, invertebrate drift, optimal foraging, predation, prey size and abundance, Salmonidae, search image, streams

The effect of variety, type of straw and ammonia treatment on digestibility and growth rate in steers

1987 ◽  
Vol 1987 ◽  
pp. 71-71
Author(s):  
G. W. Reid ◽  
E. R. Ørskov ◽  
M. Kay
Keyword(s):  
Nutritional Value ◽  
Digestive System ◽  
Nutritive Value ◽  
Energy Content ◽  
Practical Significance ◽  
Cereal Straw ◽  
Large Numbers ◽  
Medium Quality ◽  
Gross Energy ◽  
Feeding Trials

The gross energy content of cereal straw is almost as high as that of grain, but, because straw is relatively indigestible even to ruminants, much of this energy passes right through the digestive system and so makes no contribution to nutrition. Treatment of straw with alkali (normally ammonia or sodium hydroxide) improves digestibility and thus increases the amounts of energy available to animals. Straw which has been improved in this way is often said to be of similar nutritional value to medium quality hay; but responses in terms of animal performance demonstrate that this is not always so.It has been observed that the nutritive values of straws of the various cereals and of the varieties within each cereal differ considerably and that, though alkali treatments generally improve the least digestible straws the most, the differences between improved straws may still be large enough to be important. Degradability measurements carried out on large numbers of wheat, barley and oat straws to obtain an indication of nutritive value, confirm this (Tuah et al. 1986), but further evidence was needed using feeding trials with animals to support these findings and demonstrate their practical significance.

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