Extent Of Disappearance Research Articles

260 Comparison of nutrients and in vitro degradability of ryegrass (Lolium Multiforum L.) and alfalfa (Medicago Sativa L.) in central region of Turkey

Abstract Study was conducted to determine the adaptability of ryegrass to the ration of ruminants in central region of Turkey. Both ryegrass and alfalfa were planted in Cankiri and Corum cities which are located in similar geographic and climatic conditions. Forage samples were obtained during second, third and fourth harvesting times. in each sample, dry matter (DM), crude fat (EE), crude protein (CP), crude ash (CA), crude cellulose (CS), acid detergent fiber (ADF) and neutral detergent fiber (NDF) levels were determined based on AOAC methods. Metabolizable Energy levels of both ryegrass and alfalfa were calculated. In vitro disappearance of dry matter was measured by incubation of dacron bags in rumen fluid for 72 hours in Ankom® daisy incubator and extent of disappearance were determined. Generalized linear model was applied to analyze data and means were separated by using LSD. Although dry matter levels were similar (P > 0,05), ash and fat levels were significantly higher in ryegrass than those in alfalfa (P < 0,05). Additionally, as it was expected, crude protein content of ryegrass was significantly lower than that of alfalfa (P < 0,05). NDF contents of both feeds were similar and ADF levels of alfalfa were slightly higher in only second harvest date. Metabolizable energy levels of ryegrass in all harvested times were statistically higher than those in all harvested dates in alfalfa (P < 0,05). DM disappearance of ryegrass was significantly higher than that of alfalfa (P < 0,05). In conclusion, ryegrass may have some advantages in regions with limited forage sources. Additionally it may be alternative or substitute to the traditional small grain forages. Further research needed to show those advantages of ryegrass in nutrients to extrapolate consumption preferences or performance of beef or dairy cattle.

In vitro response to EPA, DPA, and DHA: Comparison of effects on ruminal fermentation and biohydrogenation of 18-carbon fatty acids in cows and ewes.

The modulation of milk fat nutritional quality through fish oil supplementation seems to be largely explained by the action of n-3 very long chain polyunsaturated fatty acids (PUFA) on ruminal biohydrogenation (BH) of C18 fatty acids (FA). However, relationships among this action, disappearance of those PUFA in the rumen, and potential detrimental consequences on ruminal fermentation remain uncertain. This study compared the effect of 20:5n-3 (eicosapentaenoic acid; EPA), 22:5n-3 (docosapentaenoic acid; DPA), and 22:6n-3 (docosahexaenoic acid; DHA) on rumen fermentation and BH of C18 FA and was conducted simultaneously in cows and sheep to provide novel insights into interspecies differences. The trial was performed in vitro using batch cultures of rumen microorganisms with inocula collected from cannulated cows and ewes. The PUFA were added at a dose of 2% incubated dry matter, and treatment effects on ruminal C18 FA concentrations, PUFA disappearances, and fermentation parameters (gas production, ammonia and volatile FA concentrations, and dry matter and neutral detergent fiber disappearances) were examined after 24 h of incubation. A principal component analysis suggested that responses to PUFA treatments explained most of the variability; those of ruminant species were of lower relevance. Overall, EPA and DHA were equally effective for inhibiting the saturation of trans-11 18:1 to 18:0 and had a similar influence on ruminal fermentation in cows and sheep (e.g., reductions in gas production and acetate:propionate ratio). Nevertheless, DHA further promoted alternative BH pathways that lead to trans-10 18:1 accumulation, and EPA seemed to have specific effects on 18:3n-3 metabolism. Only minor variations attributable to DPA were observed in the studied parameters, suggesting a low contribution of this FA to the action of marine lipids. Although most changes due to the added PUFA were comparable in bovine and ovine, there were also relevant specificities, such as a stronger inhibition of 18:0 formation in cows and a greater increase in 18:3n-3 metabolites in sheep. No direct relationship between in vitro disappearance of the incubated PUFA and effect on BH (in particular, inhibition of the last step) was found in either cows or ewes, calling into question a putative link between extent of disappearance and toxicity for microbiota. Conversely, an association between the influence of these PUFA on ruminal lipid metabolism and fermentation may exist in both species. In vivo verification of these findings would be advisable.

Ruminal crude protein degradability parameters of some feedstuffs using in situ technique

The in situ technique has been used widely for estimating ruminal nutrient degradation and to provide estimates of both the rate and extent of disappearance of feed constituents (Mehrez and Ørskov, 1977), because it is a relatively simple, low-cost method compared with methods involving intestinally cannulated animals. This technique provides a useful means to estimate rates of disappearance and potential degradability of feedstuffs and feed constituents. The technique involves suspending bags containing different feedstuffs in the rumen and measuring nutrient disappearance at various time intervals. Hence, it also may provide an advantage compared with laboratory methods because it involves digestive processes that occur in the rumen of a living animal; however, several factors affect estimates of nutrient digestion and need to be controlled for this technique to be standardised. Feeding by-products to dairy cows and other livestock will probably continue to increase in the future. By-product feeds fed to dairy cows and other livestock prevents a waste disposal problem for industry and reduces the amount of concentrate that must be included in the diet to ensure maximum animal performance. The object of this study was to estimate in situ crude protein degradability of dried grape by-product (DGB), noodle waste (NW), tomato pomace (TP), apple pomace (AP) and grape pomace (GP) using the in situ technique.

Effects of Cubing Alfalfa Hay on Development of Yearling Beef Heifers and In Situ Rate and Extent of Disappearance

The objective of this study was to evaluate the effects of cubing alfalfa on heifer development and in situ ruminai NDF and CP disappearance. One hundred ninety-two prepuberal crossbred heifers were allotted to 16 pens with each pen randomly allotted to treatment; 1) cubed alfalfa (CA) or 2) long alfalfa (LA). Diets were consumed ad libitum. Heifers were weighed every 28 d throughout the 96-d trial. Following synchronization, heifers were bred by AI 12h after observed estrus. Hay intake by CA heifers was lower (P<.05) than LA heifers (11.6 vs 13.5kg per head per d), but ADG was faster (P<.05) for CA heifers than those fed LA (1.35 vs 1.03kg per head per d). Feed per kilogram of gain was lower (P<.05) for heifers fed CA than for heifers fed LA (8.6 vs 13.2kg:kg). No differences were observed in number of heifers bred AI (P>.25)or in total pregnancy (P>.25). Six mature beef cows fitted with ruminal cannula were used in a switchback design to determine influence of cubing on in situruminal CP and NDF disappearance. During each period animals consumed their respective diets ad libitum for 14 d of adaptation and 5 d of data collection. Nylon bags containing 5-g samples of either CA or LA were ruminally incubated for 12,24,36,48,72, and 96h. Bag residues were analyzed for DM, CP, and NDF content. The DM and NDF disappearance rate constants and extent of DM disappearance for CA (.27, .11, and 79.6%, respectively) were higher (P<.04) than LA(.16, .08, and 68.1%, respectively). Crude protein rate constants were similar (P>.05) forCA (.33) and LA (.28). Results from the heifer development trial suggest that heifers fed CA gained faster and were more efficient than heifers fed LA. No differences were detected in reproductive performance, possibly because all heifers reached the recommended weight for puberty at the beginning of the breeding season regardless of treatment (average, 409kg). Results from the in situ trial indicate ruminal DM and NDF disappearance were enhanced by cubing alfalfa, but not rate of CP disappearance.

Effects of mastication and microbial contamination on ruminal in situ forage disappearance.

In an experiment to determine the effects of mastication and microbial contamination on in situ forage disappearance, samples of masticated (M) or nonmasticated alfalfa hay (AH), orchardgrass hay (OGH) and bermudagrass hay (BGH) were incubated in the rumen of two steers for 6, 12, 24, 48 and 96 h. Using diaminopimelic acid as a marker, microbial DM and CP contamination ranged from 10.3 to 22.3% and 46.3 to 95.3% of residual DM and CP, respectively. Percentage contamination was influenced by both time of incubation and forage treatment (P less than .001). Corrected DM and CP disappearances (DMD and CPD) were higher than apparent disappearances (P less than .001). Maximal NDF and ADF disappearances (NDFD and ADFD) obtained at 96 h were 58.2, 52.4; 62.7, 62.3 and 56.7, 52.6% for AH, OGH and BGH, respectively. Lag times (h) for corrected DMD and CPD were shorter (at least P less than .05) than for apparent disappearances, except for corrected CPD of AH. There were no differences (P greater than .10) in lag time of NDFD or ADFD among forages. Rates of disappearance (%/h) of corrected DMD and CPD were faster (at least P less than .01) than for apparent disappearances. The total quantity of microbial CP (mg CP/g DM) associated with residues varied with time depending on forage type (P less than .001). There was a significant relationship between the quantity of microbial CP contamination and the extent of disappearance. Masticated forages followed trends similar to those of nonmasticated forages, but the effect of mastication was not consistent. Results support the need for microbial correction of in situ forage residues.

Kinetics of In Vitro Cell‐Wall Disappearance and In Vivo Digestion

AbstractUnderstanding the dynamics or kinetics of digestion and passage may suggest ways to manipulate forages to improve the diet, and consequently the production, of domesticated ruminants. The methodology of fitting exponential curves was tested using simulated cell‐wall‐disappearance curves with both an exponential and a gamma‐distributed exponential driving function and normal‐random variation superimposed. Nonlinear regression gave more precise estimates of the true rates of digestion and lag times than linearization. The gamma distributed exponential gave lower residual sum of squares but estimates of digestible and indigestible fractions as well as lag times and disappearance rates were not improved over the simpler exponential function. Estimates were less precise when the gamma‐distributed exponential was the driving function for the disappearance curve and the gamma function was skewed. The use of the exponential decay constant (k) in studies of cell‐wall composition is confounded with extent of disappearance as a result of plant anatomy. A surface area fermentability index (SAFI) is proposed as (kCd)/(1000 − Ci) where Cd and Ci are the digestible and indigestible fractions, respectively, of the cell wall. The SAFI was used to adjust literature values for k as well as to partially explain observed negative correlations between extent and rate of cell‐wall disappearance (k) in bromegrass (Bromus inermis Leyss.) that had been selected for high and low in vitro dry matter disappearance. Study of in vivo kinetics is complicated by variable rate of passage, particle size, and extent and rate of particle size reduction. Models of in vivo kinetics offer an opportunity for synthesis of understanding of the animal system. However, the many interactions make interpretation and incorporation of in vitro data into models of in vivo ruminant digestion difficult.

Effects of pre-weaning undernutrition and post-weaning rehabilitation on polyphosphoinositide pools in rat brain regions.

In order to assess the effects of undernutrition during the pre-weaning period on polyphosphoinositide (PolyPI) pools in rat cerebral cortex, brain stem, and cerebellum, dams were fed 5% (L-) or 22% (L+) protein diets from birth to weaning and the pups were used at this age for analyses. To examine rehabilitation post-weaning, L- and L+ pups were fed 22% protein diets (P+) for an additional six week period. Rats were decapitated and the dissection begun either immediately ("0 min" samples) or 10 min later (10 min samples). Body and tissue weights, and cerebroside levels were determined in addition ot PolyPI concentrations. In brain the extent of disappearance of PolyPI during the 10 min post-mortem period paralleled the content of gray matter: cerebral cortex greater than cerebellum greater than brain stem in all groups regardless of diet. Levels of PtdIns4P and PtdIns4,5P2 were decreased by 40% and 70% respectively in cerebral cortex of L- "0 min" samples. Deficits of both lipids in brain stem and cerebellum were 40-50%. In the L- 10 min samples, deficits were 20-30% in all three regions as compared with L+ 10 min levels, indicating the presence of a portion of both lipids affected only moderately by nutritional insufficiency. The effects on this relatively inert pool, much of it localized in myelin, were reversed on nutritional rehabilitation. The PolyPI pool lost post-mortem in L+ brain regions was practically absent in L- brain regions and was not restored in L-P+ animals. Thus, this study indicates that a metabolically labile pool, primarily located in gray matter structures, is more sensitive to nutritional deprivation during the pre-weaning period than the more stable pool. The precise role and function of these pools remain to be determined.

Creation of reactive centers on cotton. II

Acrylamidomethylated cellulose (AMC) was prepared by reacting cellulose with N-methylolacrylamide or its ethers in acidic medium under a variety of conditions. The extent of the reaction, expressed as mmole double bonds per 1 g cellulose, increased by increasing the concentration of N-methylolacrylamide or its ethers. However, the paddry-cure technique produced AMC with greater amounts of double bonds than the pad-batch technique. Also, the reactivity of the etherifying agents follow the order N-methylolacrylamide>N-methoxymethylacrylamide>N-methoxymethylmethacrylamide. Furthermore, the behavior of AMC in neutral, alkaline, and acidic media was studied. No change in the amount of the pendent double bonds of AMC occurred in neutral medium regardless of the conditions employed. On the contrary, disappearance of the double bonds took place in alkaline medium. The extent of disappearance depends on the kind of alkali used as well as on the conditions implemented. It was disclosed that consumption of the pendent double bonds of AMC occurred mainly via addition of the cellulose hydroxyls to yield a crosslinked cellulose. Treatment with hydrochloric acid, on the other hand, resulted in partial splitting of the acrylamidomethyl groups as well as addition of the acid on the pendent double bonds of AMC.

Insulin disposition in the isolated perfused rat heart. Effect of "bound" insulin.

Hearts from fed and fasted rats were perfused with modified Krebs-Ringer bicarbonate buffer containing 3 per cent human serum albumin, 2 mg./ml. glucose and 100 or 200 μU./ml. crystalline insulin. The concentration of immunoassayable insulin in the medium decreased, during two hours of perfusion, to approximately 50 per cent of the initial concentration. Perfusion of hearts with insulin-I-131 (100 μU./ml.) resulted in: (1) a decrease in immunoprecipitable radioactivity corresponding in rate and extent to that of crystalline insulin; (2) a significantly smaller decrease in trichloracetic acid (TCA)-precipitable radioactivity; (3) a corresponding accumulation of a fraction of radioactivity which was TCA-precipitable but not immunoprecipitable (TCA-nonimmunoprecipitable) as well as an increase in TCA-soluble radioactivity. Immunoprecipitable-I-131 and not TCA-precipitable I-131 more accurately reflects the fate of intact insulin. Analysis of the two-hour perfusate by gel nitration chromatography (Sephadex G-100) indicated that radioactivity was associated with both the insulin-I-131 peak (M.W. 12,000) and with substances exhibiting a lower molecular weight. Thus, the disappearance of insulin during heart perfusion may be largely accounted for by degradation of insulin. Both immunoassayable insulin and immunoprecipitable insulin-I-131 were demonstrated to decrease in concentration in cell-free medium which had been previously perfused through the heart for two hours, but not in unperfused medium. The extent of disappearance was less than that during a two-hour heart perfusion. Thus, a portion of the degradation of insulin occurring during heart perfusion is probably due to the action of enzymes which diffuse into the medium from the heart. “Bound” insulin inhibited the disappearance of both crystalline insulin and immunoprecipitable I-131 radioactivity from the medium during heart perfusion. “Bound” insulin was shown to inhibit the rate of disappearance of immunoprecipitable radioactivity from preperfused medium. During perfusions with “Bound” insulin alone, the level of bioassayable activity in the medium remained constant throughout the perfusion, indicating a lack of disappearance of “Bound” insulin from the medium and vascular space of the heart. Studies of glucose uptake during heart perfusion demonstrated that “Bound” insulin has minimal or no effect on basal and insulin-stimulated glucose uptake. “Bound” insulin may inhibit the disappearance of insulin by interfering with the transport of insulin across the capillary wall and/or by inhibiting the degradation of insulin in the medium.