Effect of intraruminal infusions of volatile fatty acids on the intake of a low-digestibility straw by sheep

1993 ◽  
Vol 1993 ◽  
pp. 110-110
Author(s):  
S. López ◽  
F. D. de B. Hovell
Keyword(s):  
Fatty Acids ◽  
Feed Intake ◽  
Volatile Fatty Acids ◽  
Forage Quality ◽  
Salivary Flow ◽  
Short Term ◽  
High Quality ◽  
Chemical Factors ◽  
Voluntary Intake ◽  
Different Doses

The voluntary intake of roughage diets by ruminants is related to their degradation characteristics (Hovell et al., 1986). Furthermore, as forage quality is improved the outflow of undegraded particles is increased. Previous studies have shown that differences between forages in outflow from the rumen were mainly associated with the outflow of liquid from the rumen. In this context there could be chemical factors arising from the rapid fermentation of the more degradable forages that could stimulate salivary flow or movement of water across the rumen wall, increasing liquid outflow from the rumen, and thus washing undegraded residues from the rumen and enabling the animal to eat more. One possible signal is rumen volatile fatty acids (VFA) levels since YFA production and concentration are significantly greater with roughages that support greater intakes and rumen outflows. Intraruminal infusions of VFA have been shown to depress feed intake in ruminants (Baile & Forbes, 1974). However, most of the infusion studies have been conducted with animals fed diets containing concentrates or high-quality forages, and most of them examined short-term intake responses to intraruminal infusions of, probably, supraphysiological levels of VFA (Dejong, 1986). The aim of this experiment was to examine whether the voluntary intake of a low quality roughage by sheep could be affected by the infusion of VFA at different doses into the rumen.

Nutritional status and intake regulation in sheep. V. Effects of intraruminal infusions of volatile fatty acids upon voluntary intake of roughage by sheep

1966 ◽  
Vol 17 (5) ◽  
pp. 741 ◽  
Author(s):  
AR Egan
Keyword(s):  
Fatty Acids ◽  
Acetic Acid ◽  
Energy Balance ◽  
Nutritional Status ◽  
Propionic Acid ◽  
Feed Intake ◽  
Volatile Fatty Acids ◽  
Voluntary Intake ◽  
Induced Changes ◽  
Intake Regulation

Results of experiments with infusions of volatile fatty acids into the rumen reveal that the induced changes in voluntary intake of roughages are not immediate, and vary in extent between animals. Single infusions resulted in subsequent depressions of feed intake, these being only partly related to the amount of energy of the infused volatile fatty acids. When longer-term infusions were made, acetic acid in small quantities depressed feed intake more than did propionic, and propionic acid modified the effect of acetic when the two were given together. Also recorded is an observation that animals receiving a casein-supplemented roughage diet reduced their feed intake when casein was infused per duodenum over 14-day periods. Results are discussed in relation to an hypothesis of an indirect mechanism attempting to maintain or restore the original energy balance, but showing considerable delay or inertia and imprecision when observed on a day to day basis.

scholarly journals Effect of underfeeding on metabolism of portal-drained viscera in ewes

2000 ◽  
Vol 84 (6) ◽  
pp. 821-828 ◽  
Author(s):  
Pierre Nozière ◽  
Didier Rémond ◽  
Laurence Bernard ◽  
Michel Doreau
Keyword(s):  
Amino Acids ◽  
Fatty Acids ◽  
Feed Intake ◽  
Volatile Fatty Acids ◽  
Essential Amino Acids ◽  
Short Term ◽  
Arterial Concentration ◽  
Net Uptake ◽  
Net Release ◽  
Total Amino Acids

We investigated whether short-term underfeeding could induce adaptative mechanisms in portal-drained viscera (PDV) that would allow nutrients to be spared for vital functions in adult ewes. Six ewes (three of them fitted with catheters in the mesenteric artery and portal and mesenteric veins) were fed, in a double 3×3 Latin square design (2 weeks per experimental period), a regrowth of natural grassland hay at 143 (high; H), 88 (medium; M) and 51 (low; L) % of their energy maintenance requirements. The digestibility of the diet was measured in all six ewes and the net portal fluxes of nutrients in the three catheterized ewes. The organic matter content and N digestibility of the diet were not affected by underfeeding. Urinary and faecal N losses and N balance were linearly related to feed intake. Arterial concentration of acetate was linearly related to feed intake. Arterial concentrations of the other volatile fatty acids, 3-hydroxybutyrate, lactate, glucose, NH3, urea and total amino acids were not affected by underfeeding. Arterial concentration of non-esterified fatty acids (NEFA) increased with underfeeding. The portal net release of all volatile fatty acids, 3-hydroxybutyrate and NH3were linearly related to intake. The portal net flux of both essential and non-essential amino acids, and thus total amino acids, remained unchanged between levels H and M, and decreased between levels M and L. A significant net uptake for glycine and total non-essential amino acids occurred at level L. The portal net uptake of glucose, urea, glutamate and glutamine, and the portal net release of lactate and NEFA were not affected by underfeeding. Summation of portal energy fluxes indicated that 51 % of the metabolizable energy intake was recovered in the portal blood with the three levels of intake. In conclusion, no quantitative adaptation to spare energy, in terms of percentage of intake, occurred in PDV of short-term underfed ruminants, but the pattern of absorption of energetic nutrients was modified.

Effects of varying silage quality for dry cows on feed intake, weight change and performance in the subsequent lactation

2000 ◽  
Vol 2000 ◽  
pp. 142-142
Author(s):  
R. J. Dewhurst ◽  
D. W. R. Davies ◽  
W. J. Fisher
Keyword(s):  
Milk Production ◽  
Metabolic Activity ◽  
Feed Intake ◽  
Nutrient Supply ◽  
Current Experiment ◽  
High Quality ◽  
Grass Silage ◽  
Silage Quality ◽  
Voluntary Intake ◽  
And Performance

Earlier studies (e.g. Dewhurst et al., 1996, 1999) have shown marked declines in forage voluntary intake as calving approaches. The resultant reduction in nutrient supply may compromise performance in the next lactation, because it coincides with a period of intense metabolic activity in preparation for the next lactation. Feeding concentrates to dry cows did not overcome this problem (Dewhurst et al., 1999). The objective of the current experiment was to investigate alternative dry cow strategies, using only high-quality grass silage, to minimise the severity and consequences for subsequent milk production of the reduction in nutrient supply in this period.

Effects of level of intake and urea supplementation of alkali-treated straw on protozoal and bacterial nitrogen synthesis in the rumen and partition of digestion in cattle

1988 ◽  
Vol 39 (6) ◽  
pp. 1181 ◽  
Author(s):  
BS Punia ◽  
J Leibholz ◽  
GJ Faichney
Keyword(s):  
Fatty Acids ◽  
Feed Intake ◽  
Volatile Fatty Acids ◽  
Rumen Fluid ◽  
Water Volume ◽  
Medium Size ◽  
Total Volatile ◽  
High Feed ◽  
High Level ◽  
Microbial N

Six Friesian heifers (c. 300 kg) fitted with cannulas were given diets of wheat straw sprayed with NaOH (4.4 % wlw) and essential minerals either with or without urea (3% w/w). The total protozoal numbers in the rumen fluid were not significantly different between dietary trcatments (mean 6.2 X 104/ml). However, there were more holotrichs and medium-size entodiniomorph protozoa in the rumen fluid of the cattle given the HU and LU diets than the Hand L diets. Protozoal counts in the omasal fluid were 44% of those in rumen fluid. The apparent digestibilities of OM and neutral-detergent fibre (NDF) in the stomach and in the total tract were lower with high than low feed intakes. The urea supplement enhanced the digestibilities of OM and NDF in the stomach and in the total tract. The total nitrogen (N) and non-ammonia N (NAN) flowing to the omasum and to the duodenum per unit of N intake were significantly greater with the low than the high feed intakes and with urea supplementation of the diets than without urea supplementation. The proportions of total microbial N and bacterial N in omasal NAN were higher with the supplement of urea than the unsupplemented straw. The bacterial N in the NAN flowing to the omasum was lower for the high than the low intakes. Concentrations of ammonia-N and total volatile fatty acids in rumen fluid were higher for the ureasupplemented straw than the unsupplemented straw. The high level of feed intake was associated with higher water volume and solid contents in the rumen.

9.4 Voluntary Intake in Ruminants Affected by Silage Extracts and Amines in Particular

1982 ◽  
Vol 6 ◽  
pp. 180-182
Author(s):  
J. G. Buchanan-Smith
Keyword(s):  
Food Intake ◽  
Butyric Acid ◽  
Feed Intake ◽  
Dry Matter ◽  
Gamma Amino Butyric Acid ◽  
Maize Silage ◽  
Short Term ◽  
Amino Butyric Acid ◽  
Voluntary Intake

Gamma amino butyric acid (GABA) is a food intake depressant (Morley, 1980) and is quantitatively a significant nitrogenous constituent in silage (Oshima and McDonald, 1978). When maize silage extracts were infused into the rumen of sheep, it was shown that short-term feed intake could be depressed but this effect was attributed to high rumen osmolality (Phillip, Buchanan-Smith and Grovum, 1981) The purpose of the present experiments was to determine whether GABA and low dry matter lucerne silage extracts could depress food intake in sheep.

The inter-relationships of individual proteins and carbohydrates during fermentation in the rumen of the sheep. I. The fermentation of casein in the presence of starch or other carbohydrate materials

1958 ◽  
Vol 51 (1) ◽  
pp. 108-118 ◽  
Author(s):  
D. Lewis ◽  
I. W. McDonald
Keyword(s):  
Amino Acids ◽  
Fatty Acids ◽  
Volatile Fatty Acids ◽  
Ammonia Concentration ◽  
Microbial Synthesis ◽  
High Quality ◽  
Comparable Rate ◽  
Protein Supplements ◽  
Utilization Of Protein ◽  
Metabolic Interactions

1. The metabolic interactions of casein and starch or other carbohydrates are measured by estimating the concentrations of volatile fatty acids, ammonia, lactic acid and amino acids in the rumen after administering the protein and carbohydrate supplements alone or together.2. The ammonia concentration is reduced (i.e. its utilization is probably increased), by the carbohydrate materials; levan and starch achieve this slightly more effectively than glucose or xylan and the effect of cellulose is very slight.3. Under conditions when the normal ration fed is not of high quality a small supplement of casein stimulates the rate of fermentation of starch and other carbohydrates.4. The findings indicate that the best utilization of protein supplements is probably obtained when a carbohydrate is also present that can be fermented at a comparable rate, conditions which stimulate microbial synthesis in the rumen.

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