101 research outputs found
Role of physically effective fiber and estimation of dietary fiber adequacy in high-producing dairy cattle
Highly fermentable diets require the inclusion of adequate amounts of fiber to
reduce the risk of subacute rumen acidosis (SARA). To assess the adequacy of
dietary fiber in dairy cattle, the concept of physically effective neutral
detergent fiber (peNDF) has received increasing attention because it
amalgamates information on both chemical fiber content and particle size (PS)
of the feedstuffs. The nutritional effects of dietary PS and peNDF are complex
and involve feed intake behavior (absolute intake and sorting behavior),
ruminal mat formation, rumination and salivation, and ruminal motility. Other
effects include fermentation characteristics, digesta passage, and nutrient
intake and absorption. Moreover, peNDF requirements depend on the
fermentability of the starch source (i.e., starch type and endosperm
structure). To date, the incomplete understanding of these complex
interactions has prevented the establishment of peNDF as a routine method to
determine dietary fiber adequacy so far. Therefore, this review is intended to
analyze the quantitative effects of and interactions among forage PS, peNDF,
and diet fermentability with regard to rumen metabolism and prevention of
SARA, and aims to give an overview of the latest achievements in the
estimation of dietary fiber adequacy in high-producing dairy cattle. Recently
developed models that synthesize the effects of both peNDF and fermentable
starch on rumen metabolism appear to provide an appropriate basis for
estimation of dietary fiber adequacy in high-producing dairy cows. Data
suggest that a period lasting more than 5 to 6h/d during which ruminal pH is
<5.8 should be avoided to minimize health disturbances due to SARA. The
knowledge generated from these modeling approaches recommends that average
amounts of 31.2% peNDF inclusive particles >1.18mm (i.e., peNDF(>1.18)) or
18.5% peNDF inclusive particles >8mm (i.e., peNDF(>8)) in the diet (DM basis)
are required. However, inclusion of a concentration of peNDF(>8) in the diet
beyond 14.9% of diet DM may lower DM intake level. As such, more research is
warranted to develop efficient feeding strategies that encourage inclusion of
energy-dense diets without the need to increase their content in peNDF above
the threshold that leads to lower DM intake. The latter would require
strategies that modulate the fermentability characteristics of the diet and
promote absorption and metabolic capacity of ruminal epithelia of dairy cows
Differences in intestinal size, structure, and function contributing to feed efficiency in broiler chickens reared at geographically distant locations
peer-reviewedThe contribution of the intestinal tract to differences in residual feed intake (RFI) has been inconclusively studied in chickens so far. It is also not clear if RFI-related differences in intestinal function are similar in chickens raised in different environments. The objective was to investigate differences in nutrient retention, visceral organ size, intestinal morphology, jejunal permeability and expression of genes related to barrier function, and innate immune response in chickens of diverging RFI raised at 2 locations (L1: Austria; L2: UK). The experimental protocol was similar, and the same dietary formulation was fed at the 2 locations. Individual BW and feed intake (FI) of chickens (Cobb 500FF) were recorded from d 7 of life. At 5 wk of life, chickens (L1, n = 157; L2 = 192) were ranked according to their RFI, and low, medium, and high RFI chickens were selected (n = 9/RFI group, sex, and location). RFI values were similar between locations within the same RFI group and increased by 446 and 464 g from low to high RFI in females and males, respectively. Location, but not RFI rank, affected growth, nutrient retention, size of the intestine, and jejunal disaccharidase activity. Chickens from L2 had lower total body weight gain and mucosal enzyme activity but higher nutrient retention and longer intestines than chickens at L1. Parameters determined only at L1 showed increased crypt depth in the duodenum and jejunum and enhanced paracellular permeability in low vs. high RFI females. Jejunal expression of IL1B was lower in low vs. high RFI females at L2, whereas that of TLR4 at L1 and MCT1 at both locations was higher in low vs. high RFI males. Correlation analysis between intestinal parameters and feed efficiency metrics indicated that feed conversion ratio was more correlated to intestinal size and function than was RFI. In conclusion, the rearing environment greatly affected intestinal size and function, thereby contributing to the variation in chicken RFI observed across locations
Feeding barley grain-rich diets altered electrophysiological properties and permeability of the ruminal wall in a goat model
High-producing ruminants are commonly fed large amounts of concentrate to meet
their high energy demands for rapid growth or high milk production. However,
this feeding strategy can severely impair rumen functioning, leading to
subacute ruminal acidosis. Subacute ruminal acidosis might have consequences
for electrophysiological properties by changing the net ion transfer and
permeability of ruminal epithelia, which may increase the uptake of toxic
compounds generated in the rumen into the systemic circulation. The objective
of the present study was to investigate the effects of excessive barley
feeding on the electrophysiological and barrier functions of the ruminal
epithelium and serum inflammation and ketogenesis markers after a long-term
feeding challenge, using growing goats as a ruminant model. A feeding trial
was carried out with growing goats allocated to 1 of the 3 groups (n=5-6
animals/group), with diets consisting exclusively of hay (control diet) or hay
with 30 or 60% barley grain. Samples of the ventral ruminal epithelium were
taken after euthanasia and instantly subjected to Ussing chamber experiments,
where electrophysiological properties of the epithelium were measured in
parallel with the permeability of marker molecules of different sizes
[fluorescein 5(6)-isothiocyanate and horseradish peroxidase] from luminal to
apical side. Additionally, ruminal fluid and blood samples were taken at the
beginning of the experiment as well as shortly before euthanasia. Ruminal
fluid samples were analyzed for volatile fatty acids and pH, whereas blood
samples were analyzed for lipopolysaccharide, serum amyloid A, and
β-hydroxybutyrate. Electrophysiological data indicated that barley feeding
increased the epithelial short-circuit current compared with the control.
Tissue conductance also increased with dietary barley inclusion. As shown with
both marker molecules, permeability of ruminal epithelia increased with barley
inclusion in the diet. Despite a lowered ruminal pH associated with increased
volatile fatty acids (such as propionate and butyrate) concentrations as well
as altered epithelial properties in response to high-grain feeding, no signs
of inflammation became apparent, as blood serum amyloid A concentrations
remained unaffected by diet. However, greater amounts of grain in the diet
were associated with a quadratic increase in lipopolysaccharide concentration
in the serum. Also, increasing the amounts of barley grain in the diet
resulted in a tendency to quadratically augment serum concentrations of
β-hydroxybutyrate and, hence, the alimentary ketogenesis. Further studies are
needed to clarify the role of barley inclusion in the development of subacute
ruminal acidosis in relation to ruminal epithelial damage and the
translocation of toxic compounds in vivo. Copyright © 2013 American Dairy
Science Association. Published by Elsevier Inc. All rights reserved
Effects of different sources of carbohydrates on intake, digestibility, chewing, and performance of Holstein dairy cows
High-concentrate feeding upregulates the expression of inflammation-related genes in the ruminal epithelium of dairy cattle
Benefits for Dominant Red Deer Hinds under a Competitive Feeding System: Food Access Behavior, Diet and Nutrient Selection
Social dominance is widely known to facilitate access to food resources in many animal species such as deer. However, research has paid little attention to dominance in ad libitum access to food because it was thought not to result in any benefit for dominant individuals. In this study we assessed if, even under ad libitum conditions, social rank may allow dominant hinds to consume the preferred components of food. Forty-four red deer hinds (Cervus elaphus) were allowed to consume ad libitum meal consisting of pellets of sunflower, lucerne and orange, and seeds of cereals, corn, cotton, and carob tree. The meal was placed only in one feeder, which reduced accessibility to a few individuals simultaneously. During seven days, feeding behavior (order of access, time to first feeding bout, total time spent feeding, and time per feeding bout) were assessed during the first hour. The relative abundance of each meal component was assessed at times 0, 1 and 5 h, as well as its nutritional composition. Social rank was positively related to the amount of time spent feeding during the 1st h (P = 0.048). Selection indices were positively correlated with energy (P = 0.018 during the 1st h and P = 0.047 from 1st to 5th) and fat (only during the 1st h; P = 0.036), but also negatively with certain minerals. Thus, dominant hinds could select high energy meal components for longer time under an ad libitum but restricted food access setting. Selection indices showed a higher selectivity when food availability was higher (1st hour respect to 1st to 5th). Finally, high and low ranking hinds had longer time per feeding bout than mid ones (P = 0.011), suggesting complex behavioral feeding tactics of low ranking social ungulates
Occurrence of retained placenta is preceded by an inflammatory state and alterations of energy metabolism in transition dairy cows
A high-concentrate diet induced colonic epithelial barrier disruption is associated with the activating of cell apoptosis in lactating goats
Assessing serum metabolite profiles as predictors for feed efficiency in broiler chickens reared at geographically distant locations
- …