Diet and diet selection of two species in the macropodid browser–grazer continuum— do they eat what they 'should'?

2002 ◽  
Vol 50 (2) ◽  
pp. 183 ◽  
Author(s):  
J. A. Sprent ◽  
C. McArthur

On the basis of their dentition, species of Macropus are predicted to be grazers and species of Thylogale are predicted to be browsers. We tested these predictions by comparing diet and diet selection of the red-necked wallaby (Macropus rufogriseus rufogriseus) and red-bellied pademelon (Thylogale billardierii), by analysing forestomach contents of animals that had fed in the same region of a young pine plantation. Grasses, followed by broad-leafed forbs, were the most abundant plant groups in the field (together comprising 71% of the plant biomass), and were also the main dietary components of both macropodid species (91%). No differences were detected in diet of the two species when summarised in terms of diet diversity, evenness or overlap. When diet selection was compared, however, distinct differences were found between the two species. Red-necked wallabies selected for grasses (74% of the diet compared with 55% in the field) whereas red-bellied pademelons selected for broad-leafed forbs (38% of the diet compared with 16% in the field). Feeding patterns were therefore consistent with dietary predictions, provided diet selection was considered rather than simply diet. Diet selection is more appropriate for testing dietary predictions, because it reflects animals' attempts to consume food items that they prefer, that is, that they are functionally suited to consuming, even when such items are not as abundant as less preferred food.

Metabolomics ◽  
2021 ◽  
Vol 17 (1) ◽  
Author(s):  
João Fadista ◽  
Line Skotte ◽  
Julie Courraud ◽  
Frank Geller ◽  
Sanne Gørtz ◽  
...  

Abstract Introduction Infantile hypertrophic pyloric stenosis (IHPS) is caused by hypertrophy of the pyloric sphincter muscle. Objectives Since previous reports have implicated lipid metabolism, we aimed to (1) investigate associations between IHPS and a wide array of lipid-related metabolites in newborns, and (2) address whether detected differences in metabolite levels were likely to be driven by genetic differences between IHPS cases and controls or by differences in early life feeding patterns. Methods We used population-based random selection of IHPS cases and controls born in Denmark between 1997 and 2014. We randomly took dried blood spots of newborns from 267 pairs of IHPS cases and controls matched by sex and day of birth. We used a mixed-effects linear regression model to evaluate associations between 148 metabolites and IHPS in a matched case–control design. Results The phosphatidylcholine PC(38:4) showed significantly lower levels in IHPS cases (P = 4.68 × 10−8) as did six other correlated metabolites (four phosphatidylcholines, acylcarnitine AC(2:0), and histidine). Associations were driven by 98 case–control pairs born before 2009, when median age at sampling was 6 days. No association was seen in 169 pairs born in 2009 or later, when median age at sampling was 2 days. More IHPS cases than controls had a diagnosis for neonatal difficulty in feeding at breast (P = 6.15 × 10−3). Genetic variants known to be associated with PC(38:4) levels did not associate with IHPS. Conclusions We detected lower levels of certain metabolites in IHPS, possibly reflecting different feeding patterns in the first days of life.


2014 ◽  
Vol 18 (1) ◽  
pp. 68-74 ◽  
Author(s):  
Johanna C Gerdessen ◽  
Olga W Souverein ◽  
Pieter van ‘t Veer ◽  
Jeanne HM de Vries

AbstractObjectiveTo support the selection of food items for FFQs in such a way that the amount of information on all relevant nutrients is maximised while the food list is as short as possible.DesignSelection of the most informative food items to be included in FFQs was modelled as a Mixed Integer Linear Programming (MILP) model. The methodology was demonstrated for an FFQ with interest in energy, total protein, total fat, saturated fat, monounsaturated fat, polyunsaturated fat, total carbohydrates, mono- and disaccharides, dietary fibre and potassium.ResultsThe food lists generated by the MILP model have good performance in terms of length, coverage and R2 (explained variance) of all nutrients. MILP-generated food lists were 32–40 % shorter than a benchmark food list, whereas their quality in terms of R2 was similar to that of the benchmark.ConclusionsThe results suggest that the MILP model makes the selection process faster, more standardised and transparent, and is especially helpful in coping with multiple nutrients. The complexity of the method does not increase with increasing number of nutrients. The generated food lists appear either shorter or provide more information than a food list generated without the MILP model.


2002 ◽  
Vol 74 (2) ◽  
pp. 357-367 ◽  
Author(s):  
S. M. James ◽  
I. Kyriazakis ◽  
G. C. Emmans ◽  
B. J. Tolkamp

AbstractThe hypotheses tested were that the expected preference of sheep for a food with adequate rumen degradable protein (RDP) supplemented with urea would be reduced both by the addition of a buffer (sodium bicarbonate (SB)) and by offering ad libitum access to hay. A control food (C), calculated to be adequate in its ratio of effective RDP to fermentable metabolizable energy (fME), was formulated. Other foods were made by adding 12·5 (U1) or 25 (U2) g urea per kg fresh matter (FM) to C and 20 g SB per kg FM to C, U1and U2. The acid buffering capacity (ABC) of each food was measured in vitro. The experiment consisted of two successive periods, each of 4 weeks. Ninety-eight female, Texel ✕ Greyface sheep were randomly allocated to 14 groups each with seven animals. Groups 1 to 6 were offered one of: C, U2, C + SB, U2+ SB, C with hay or U2with hay throughout the experiment. Groups 7 to 10 were offered the choices of C v. U1or C v. U2, either with or without hay in a change-over design; animals that received hay during period 1 (groups 8 and 10) did not do so during period 2 and vice versa (groups 7 and 9). Groups 11 to 14 (no. = 7) were offered the choices of C v. U1or C v. U2, either with or without SB supplemented to both foods, in a change-over design. Adding either urea, or SB, or both to C had no effects on intake or live-weight gain when offered alone. Both supplements significantly (P 0·001) increased the ABC of food C. Throughout the experiment hay consumption was very low (overall mean: 23 (s.e. 2·5) g hay per sheep day). Offering hay caused no change in the preference for the urea-supplemented foods. Sheep offered the choices C v. U1or C v. U2, with neither hay nor SB, selected 0.466 (s.e. 0·036) and 0.588 (s.e. 0·025) kg/kg total food intake (TFI) of U1and U2respectively. The proportions of the urea-supplemented foods were significantly reduced (P 0.01) by SB supplementation: to 0.348 (s.e.0·045) and 0·406 (s.e.0·059) kg/kg TFI of U1and U2respectively. The effect of SB addition on the diet selection of sheep could be due to its buffering properties. When SB is added to both foods the need for urea to be used as a buffer is reduced with a consequent decrease in the proportion selected as the urea-supplemented food. Effects of diet on buffering may override other diet selection objectives, such as the avoidance of an excess intake of RDP.


1983 ◽  
Vol 77 (1) ◽  
pp. 79-83 ◽  
Author(s):  
C. Morales ◽  
T. Antezana

2004 ◽  
Vol 82 (6) ◽  
pp. 922-933 ◽  
Author(s):  
D Gallant ◽  
C H Bérubé ◽  
E Tremblay ◽  
L Vasseur

The objective of this study was to examine the foraging behaviour of the beaver (Castor canadensis Kuhl, 1820) and to explain its selection of terrestrial woody plant species according to central place foraging theory. Limitations in variety of food items in most studies with regard to size and (or) distance from the central place and information on availability of forage choices give a partial view of the subject. In this study, the theory is tested in a natural environment with high variability in food items with regard to these factors. Foraging choices by beavers were inspected by measuring variables on cut and uncut trees of every species encountered within 1 m of trail systems made by 25 beaver colonies in Kouchibouguac National Park in New Brunswick, Canada, thereby quantifying the availability of the different food items. The effect of habitat quality (food availability) on the foraging behaviour of beavers was also tested. The results of this study suggest that with increasing distance from the pond, beavers in high-quality habitats selected fewer, but larger, trees and are more species selective. This selectivity was diminished in habitats of lower quality. The results of this study are consistent with the predictions of the central foraging theory.


2016 ◽  
Vol 283 (1838) ◽  
pp. 20161032 ◽  
Author(s):  
Gildas Merceron ◽  
Anusha Ramdarshan ◽  
Cécile Blondel ◽  
Jean-Renaud Boisserie ◽  
Noël Brunetiere ◽  
...  

Both dust and silica phytoliths have been shown to contribute to reducing tooth volume during chewing. However, the way and the extent to which they individually contribute to tooth wear in natural conditions is unknown. There is still debate as to whether dental microwear represents a dietary or an environmental signal, with far-reaching implications on evolutionary mechanisms that promote dental phenotypes, such as molar hypsodonty in ruminants, molar lengthening in suids or enamel thickening in human ancestors. By combining controlled-food trials simulating natural conditions and dental microwear textural analysis on sheep, we show that the presence of dust on food items does not overwhelm the dietary signal. Our dataset explores variations in dental microwear textures between ewes fed on dust-free and dust-laden grass or browse fodders. Browsing diets with a dust supplement simulating Harmattan windswept environments contain more silica than dust-free grazing diets. Yet browsers given a dust supplement differ from dust-free grazers. Regardless of the presence or the absence of dust, sheep with different diets yield significantly different dental microwear textures. Dust appears a less significant determinant of dental microwear signatures than the intrinsic properties of ingested foods, implying that diet plays a critical role in driving the natural selection of dental innovations.


1989 ◽  
Vol 67 (6) ◽  
pp. 1353-1362 ◽  
Author(s):  
Michael P. Gillingham ◽  
Fred L. Bunnell

Foraging bouts of captive black-tailed deer (Odocoileus hemionus columbianus Richardson) were investigated to examine how searching for food affects diet selection. We determined food preference for three types of food under ad libitum conditions and then studied the foraging of two deer in a 0.5-ha, vegetation-free pen in which we controlled food availability and distribution of the same three types of food. Our hypotheses included the following: (i) clumping of preferred food into patches would enable animals to better exploit food distributions; (ii) the switch from preferred to lower-ranked food would be gradual as preferred food was less frequently encountered; and (iii) deer would respond to a lower abundance of preferred foods by eating more of lower-ranked food items at each feeding location. Searching for food alone did not alter diet selection from ad libitum conditions. Deer nearly exhausted their highly preferred food item before switching to lower-ranked ones. Amount of preferred food already eaten during a trial was positively correlated with the time that animals continued searching before switching to lower-ranked food items. Switching was related to amount and type of food encountered and not to amount of food in the pen. Clumping of the preferred food had no significant effect on the amount of food eaten, but did significantly influence types of food encountered by one deer. When preferred food was abundant, it was not always completely eaten the first time a feeding platform was visited. Increases in the intake rates of nonpreferred food items resulted from deer visiting more feeding stations containing nonpreferred food items and not from deer eating more food at each feeding station.


Author(s):  
OJS Admin

Pregnancy is the time period when maternal dietary selection of food items impacts the developing fetus as well as health of mother.


2006 ◽  
Vol 34 ◽  
pp. 15-20
Author(s):  
L.M.M. Ferreira ◽  
M. Oliván ◽  
M.A.M. Rodrigues ◽  
A. Dias-da-Silva ◽  
K. Osoro

SummaryAn experiment was carried out to evaluate the use of alkanes for estimating diet composition of goats and sheep offered three different dietary treatments. Twelve animals as two groups of 4 crossbred goats (G1, 24 kg live weight; G2, 22 kg) and 4 crossbred sheep (S, 26 kg live weight), were housed in metabolism pens. Animals were offered daily a total of 1 kg DM/100 kg live weight. G1 received 70% ryegrass (Lolium perenne) and 30% gorse (Ulex gallii), G2 received 70% ryegrass and 30% heather (Erica sp.) and S group ate 100% ryegrass. Diet composition was estimated from the alkane concentrations (using all alkanes from C23 to C36 or only odd-chain alkanes C27, C29, C31 and C33) in diet and faeces (with or without correction for incomplete faecal recoveries) using least-squares procedures.Dietary treatment and animal species significantly affected alkane faecal recoveries, except for C24 and C36. When applying the faecal recovery corrections, there were no significant differences between measured proportions of dietary components and those estimated using all alkanes or odd-chain alkanes. In contrast, the proportions calculated without faecal recovery correction differed significantly (P<0.05) from the actual proportions and over-estimated the amount in the diet of those plant components with higher concentrations of long-chain alkanes (Erica sp. and Lolium perenne). The results indicate that alkanes are useful markers to estimate diet composition, however, it was observed that animal species and diet composition influenced the faecal recovery of alkanes. This suggests that the use of the alkane methodology for estimating the diet selection of grazing animals should be preceded by a calculation of the actual alkane faecal recoveries for each experimental condition.


Sign in / Sign up

Export Citation Format

Share Document