Degradable Crude Protein Fraction Research Articles

Ensiling Characteristics and the In situ Nutrient Degradability of a By-product Feed-based Silage.

This study was conducted to evaluate the ensiling characteristics and the in situ degradability of a by-product feed (BF)-based silage. Before ensilation, the BF-based mixture was composed of 50% spent mushroom substrate, 21% recycled poultry bedding, 15% ryegrass straw, 10.8% rice bran, 2% molasses, 0.6% bentonite, and 0.6% microbial inoculant on a wet basis and ensiled for up to 4 weeks. The BF-based silage contained on average 39.3% moisture, 13.4% crude protein (CP), and 52.2% neutral detergent fiber (NDF), 49% total digestible nutrient, and 37.8% physically effective NDF1.18 on a dry matter (DM) basis. Ensiling the BF-based silage for up to 4 weeks affected (p<0.01) the chemical composition to a small extent, increased (p<0.05) the lactic acid and NH3-N content, and decreased (p<0.05) both the total bacterial and lactic acid bacterial counts from 109 to 108 cfu/g when compared to that before ensiling. These parameters indicated that the silage was fermented and stored well during the 4-week ensiling period. Compared with rice or ryegrass straws, the BF-based silage had a higher (p<0.05) water-soluble and filterable fraction, a lower insoluble degradable DM and CP fraction (p<0.05), a lower digestible NDF (p<0.05) fraction, a higher (p<0.05) DM and CP disappearance and degradability rate, and a lower (p<0.05) NDF disappearance and degradability rate. These results indicated that cheap, good-quality BF-based roughage could be produced by ensiling SMS, RPB, rice bran, and a minimal amount of straw.

Effect of feeding dried distillers' grains with solubles on milk yield and milk composition of cows in mid‐lactation and digestibility in sheep

We evaluated the effect of three sources of dried distillers' grains with solubles (DDGS) in diets of mid-lactating dairy cows on milk production and milk composition and on digestibility in sheep. DDGS from wheat, corn and barley (DDGS1 ), wheat and corn (DDGS2 ) and wheat (DDGS3 ) were studied and compared with a rapeseed meal (RSM). RSM and DDGS were characterized through in situ crude protein (CP) degradability. Nutrient digestibility was determined in sheep. Twenty-four multiparous cows were used in a 4 × 4 Latin square design with 28-day periods. Treatments included total mixed rations containing as primary protein sources RSM (control), DDGS1 (D1), DDGS2 (D2) or DDGS3 (D3). RSM contained less rapidly degradable CP (fraction a), more potentially degradable CP (fraction b) and more rumen undegradable CP (UDP) than the three DDGS. In vivo digestibility of RSM organic matter was similar to DDGS. Calculated net energy for lactation (NEL ) was lower for RSM (7.4 MJ/kg DM) than for DDGS, which averaged 7.7 MJ/kg DM. Cows' dry matter intake did not differ between diets (21.7 kg/day). Cows fed D1 yielded more milk than those fed D3 (31.7 vs. 30.4 kg/day); no differences were found between control and DDGS diets (31.3 vs. 31.1 kg/day). Energy-corrected milk was similar among diets (31.2 kg/day). Diets affected neither milk fat concentration (4.0%) nor milk fat yield (1.24 kg/day). Milk protein yield of control (1.12 kg/day) was significantly higher than D3 (1.06 kg/day) but not different form D1 and D2 (1.08 kg/day each). Feeding DDGS significantly increased milk lactose concentration (4.91%) in relation to control (4.81%). DDGS can be a suitable feed in relation to RSM and can be fed up to 4 kg dry matter per day in rations of dairy cows in mid-lactation. However, high variation of protein and energy values of DDGS should be considered when included in diets of dairy cows.

Effects of Gamma Irradiation on Nutrient Composition, Anti-nutritional Factors, In vitro Digestibility and Ruminal Degradation of Whole Cotton Seed

Whole cotton seed (WCS) has become one of the major feed ingredients in TMR for dairy cattle in Korea, and WCS for feed use is mostly imported from abroad. Since this genetically modified oil seed is usually fed to the animal in raw state, its germination ability, if last long, often causes concerns about ecological disturbances. In the process of looking for effective conditions to remove germination ability of WCS this study had the objectives to evaluate the nutritional effects of gamma irradiation at doses of 8, 10 and 12 kGy on changes in nutrient contents, anti-nutritional factors, in vitro digestibility and ruminal degradability. No significant differences were found in proximate analysis of nutrients between raw WCS and gamma irradiated one. Glycine and threonine contents significantly increased when the WCS was exposed to gamma ray as compared to untreated WCS (p<0.05). As for fatty acid composition, no significant differences were observed with the irradiation treatment. Free gossypol in WCS was decreased (p<0.05) by gamma irradiation treatment. Of the 3 different levels of gamma irradiation, a dose of 12 kGy was found to be the most effective in reducing free gossypol concentration. Results obtained from in situ experiment indicated that gamma irradiation at a dose of 10 kGy significantly (p<0.05) lowered rumen degradability of both dry matter and crude protein as compared with raw WCS. However, there were no significant differences in rapidly degradable and potentially degradable fractions of crude protein due to 10 kGy gamma irradiation. Overall, this study show that gamma irradiation at a dose of 10 kGy is the optimum condition for removing germination ability of WCS, and could improve nutritive value for the ruminant with respect to the decrease in both ruminal protein degradability and gossypol content of WCS.

Variations in chemical composition and in vitro and in situ ruminal degradation characteristics of dried distillers’ grains with solubles from European ethanol plants

The objective of this study was to characterise variations in the composition and nutritive value of dried distillers’ grains with solubles (DDGS) for ruminants, and to estimate the undegradable crude protein (UDP) in DDGS. Thirteen samples originating from wheat, corn, barley and blends of different substrates were studied. The rumen degradation of crude protein (CP) was determined using the nylon bag technique. Samples were incubated for 0, 1, 2, 4, 8, 16, 32 and 72 h, and in situ degradation kinetics were determined. The UDP was estimated using a passage rate of 8%/h. In vitro gas production was measured to estimate the metabolisable energy (ME), net energy for lactation (NEL) and in vitro digestibility of organic matter (IVDOM). Chemical profiles varied among samples [in g/kg dry matter (DM) ± standard deviation]; the values were 310 ± 33 CP, 86 ± 37 ether extract, 89 ± 18 crude fibre, 408 ± 39 neutral detergent fibre, 151 ± 39 acid detergent fibre and 62 ± 31 acid detergent lignin, as well as in protein fractions according to the Cornell Net Carbohydrate and Protein System [in g/kg CP]; the values were for fractions A, 161 ± 82; B1, 24 ± 11; B2, 404 ± 105; B3, 242 ± 61; and C, 170 ± 87. The ME, NEL [MJ/kg DM] and IVDOM [%] also varied among samples: 12.1 ± 0.59, 7.3 ± 0.39 and 72.5 ± 4.30, respectively. The in situ rapidly degradable CP fraction (a) varied from 10.2% to 30.6%, and the potentially degradable fraction (b) averaged to 66.8%. The UDP varied from 8.6% to 62.6% of CP. The present study suggests significant variations in composition and nutritive value among different sources of DDGS. The UDP could be predicted on the basis of analysed CP fractions, but the accuracy of UDP prediction improved upon the inclusion of neutral-detergent insoluble nitrogen, explaining 94% of the variation in the UDP values. We conclude that chemical protein fractions may be used to predict the UDP values of DDGS and that the variability in the protein fractions of DDGS should be considered when formulating diets for dairy cows.

Effect of condensed tannins on ruminal degradability of purple prairie clover (Dalea purpurea Vent.) harvested at two growth stages

The native legume purple prairie clover (PPC; Dalea purpurea Vent.) is adapted to the prairie region of North America and contains high levels of condensed tannins (CT) with activity against Escherichia coli O157:H7. However, information on the variation of CT concentration in PPC at different growth stages is lacking. Whole plant PPC was harvested from 5 paddocks (4 samples/paddock) from native pastures at vegetative/early flowering (VEG) and full flower/early seed (FL) stages. Plants were dissected into leaf, stem and inflorescence, freeze dried and ground for determination of total phenolics (TP), CT and other nutrients. Plants harvested at VEG had similar (101 versus 111g/kg DM) TP but lower CT (59 versus 94g/kg DM; P<0.01) than those harvested at the FL stage. Inflorescences contained the highest CT (198–213g/kg DM), followed by leaves (50–64g/kg DM) and stems (17g/kg DM). Contents of organic matter, neutral detergent fibre (aNDF) and acid detergent fibre were higher (P<0.01), but N content was lower (P<0.01) for FL than VEG. Ground PPC samples from 3 paddocks at both growth stages were incubated with a mixture of ruminal fluid and mineral buffer in three DaisyII fermentors to assess ruminal degradability of DM, crude protein (CP) and aNDF. Polyethylene glycol (PEG) was added to half of the jars to define effects of CT on digestion. Bags were retrieved at intervals over 72h incubation and analyzed for N and microbial 15N. There was no growth stage by PEG interaction for the kinetic parameters a, b and c of DM degradation. Plants harvested at the VEG stage had higher (P<0.01) in vitro degradability of DM and aNDF, slowly degradable fraction (b) of DM, aNDF and CP than those harvested at the FL stage. More (P<0.01) rapidly degradable fraction (a) of DM, but less (P<0.05) rapidly degradable fraction (a) of CP occurred for VEG than FL. Inclusion of PEG increased (P<0.01) the degradation rate of the b DM fraction for both growth stages and that of aNDF at FL, while reducing (P<0.05) lag time of CP degradation for FL. Results demonstrate that PPC contains high levels of a unique CT that has a minimal impact on DM degradability, suggesting that feeding PPC may have potential to reduce E coli O157:H7 in the ruminant digestive tract without adversely impacting digestion.

Nutrient composition, polyphenolic contents, and in situ protein degradation kinetics of leaves from three mulberry species

Mulberry leaves of 14 cultivars of Morus atropurpurea Roxb (MAR), 7 cultivars of Morus alba Linn (MAL) and 8 cultivars of Morus multicaulis Perr (MMP) were assessed for their differences in chemical composition and in situ ruminal degradation. The contents of acid detergent fibre (P=0.073) and ether extract (P<0.0001) ranked as: MMP>MAL>MAR. Crude protein (CP), neutral detergent fibre and polyphenolic contents of the leaves did not differ between three species. Nylon bags containing the leaves were incubated for 2, 6, 12, 24, 36, 48 and 72h in three rumen cannulated dairy cows. Soluble CP fraction and fractional degradation rate did not differ between three species, but the potential degradable CP fraction in the leaves was greater for MAR than the others (P=0.005). Effective CP degradability was consistently ranked: MAR>MAL>MMP (P=0.051). Non-tannin phenols and total tannins were negatively correlated with the soluble CP fraction (r=−0.48, P<0.01) and the potential degradable CP fraction (r=−0.36, P<0.05), respectively. In summary, the mulberry leaves with high protein, low fibre and tannin contents could be exceptional forage for use in ruminant animals.

Chemical composition, secondary compounds, ruminal degradation and in vitro crude protein digestibility of gamma irradiated canola seed

This study was completed to evaluate effects of gamma irradiation (γ-irradiation) at doses of 15, 30 and 45 kGy on ruminal degradability, in vitro crude protein (CP) digestibility, chemical composition and secondary compounds of canola seed (CS). Three ruminally fistulated bulls were used to measure ruminal in situ dry matter (DM) and CP degradability. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) was used to monitor protein subfractions and the fate of true proteins of γ-irradiated CS in the rumen. γ-Irradiation had no effect on chemical composition of CS, but phytic acid was eliminated completely at a dose of 30 kGy. γ-Irradiation decreased the total glucosinolate contents of CS ( P<0.001). There was a linear decrease in the washout fraction and linear increase in the potentially degradable fraction of DM ( P<0.001). Effective degradability (ED) of DM decreased linearly ( P<0.001) with increases in irradiation dose. γ-Irradiation increased ( P<0.001) the potentially degradable fraction of CP from 540 to 669 g/kg. γ-Irradiation reduced ( P<0.001) the degradation rate of the b fraction of CP. ED of CP decreased ( P<0.001) with increases in irradiation dose. γ-Irradiation at doses of 30 and 45 kGy, increased in vitro CP digestibility of undegraded CP remaining in bags incubated for 16 h in the rumen by 15 and 21%, respectively. Electrophoresis showed that napin subunits of untreated CS disappeared completely within the shortest incubation periods, whereas cruciferin subunits were degraded in the middle of incubation periods. At 30 and 45 kGy γ-irradiated CS, napin subunits were degraded in the middle of the incubation and cruciferin subunits were degraded at the longest incubation periods. γ-Irradiation seems to be effective in protecting CS proteins from ruminal degradation and reducing secondary compounds in CS at doses higher than 15 kGy.

Chemical composition and nutritional evaluation of various foliages consumed by mithun ( Bos frontalis)

Mithun ( Bos frontalis) is primarily reared in free-grazing systems and several tropical foliages are important feed resources for it throughout the year. Inadequate information is available on the nutritive value of most of these foliages. This study aimed to determine the nutrient composition and in situ degradability of dry matter (DM) and crude protein (CP) of the major foliages consumed by mithun. The foliages ( n = 16) were collected from different mithun inhabited areas. The DM, CP, ether extract, neutral detergent fibre, acid detergent fibre, lignin(sa), ash and condensed tannin contents of the foliages varied from 236 to 398, 100 to 178, 10 to 40, 397 to 621, 287 to 460, 74 to 169, 92 to 176 and 12 to 68 g/kg DM, respectively. All foliages contained Ca and K at more than 10 g/kg DM and Mg at more than 1.7 g/kg DM, but were deficient in Na ( i.e., <0.6 g/kg DM). The P content of the foliages ranged from 1.2 to 4.0 g/kg DM, and contents of Cu, Fe, Mn and Zn were ranged from 7.3 to 19.6, 119 to 460, 32 to 144 and 35 to 430 mg/kg DM, respectively. The degradability of DM and CP was greater in Daubanga grandiflora compared to the other experimental foliages. Among the foliages, the rapidly degradable fraction of DM and CP ranged from 49 to 219 and 86 to 217 g/kg DM, respectively. Simultaneously, the slowly degradable fraction of DM and CP ranged from 319 to 475 and 159 to 325 g/kg DM, respectively. The effective degradability of DM and CP ranged from 291 to 389 and 199 to 338 g/kg DM, respectively. The nutrient contents were adequate in most of the foliage, except Na, which was deficient in all the foliages and may explain observed salt seeking behavior of mithun reared under free grazing systems.

Effects of microwave irradiation on ruminal dry matter, protein and starch degradation characteristics of barley grain

This study evaluated effects of microwave irradiation (800 W) for 3, 5 and 7 min on dry matter (DM), crude protein (CP) and starch degradation characteristics of barley grain and to monitor the fate of its proteins in the rumen. Duplicate in situ bags of untreated or irradiated barley grain were incubated in the rumen of four non-lactating Holstein cows for up to 48 h. Proteins of untreated and irradiated bag residues were fractionated by gel electrophoresis. Irradiation for 3 min had no effect, but for 5 and 7 min decreased (P<0.05) the effective DM degradability. The washout fraction, and the degradation rate of CP, decreased (P<0.05) and the potentially degradable CP fraction increased (P<0.05) as irradiation period increased. Effective CP degradability of barley irradiated for 3, 5 and 7 min decreased (P<0.05) by 6%, 10% and 13%, respectively. Microwave irradiation increased (P<0.05) the washout fraction and decreased (P<0.05) the potentially degradable fraction and degradation rate of starch. Irradiation for 5 min had no effect on effective starch degradability, but for 3 and 7 min increased, and decreased it (P<0.05), respectively. From electrophoretic analyses, three major hordein fractions (B-, C- and D-hordein) occurred. In untreated barley grain, most hordein fractions had disappeared after 6 h of incubation, but in microwave irradiated barley, C- and D-hordein were not degraded until 12 h of incubation in the rumen. Microwave irradiation of barley grain for 3 min increased its starch degradability and, over 5 min, decreased the rate and extent of CP and starch degradation.

Chemical composition, in situ ruminal degradability and post-ruminal disappearance of dry matter and crude protein from the halophytic plants Kochiascoparia, Atriplexdimorphostegia, Suaedaarcuata and Gamanthusgamacarpus

Samples of Kochia ( K. scoparia), Atriplex ( A. dimorphostegia), Suaeda ( S. arcuata) and Gamanthus ( G. gamacarpus) were collected and analyzed for chemical composition including crude protein (CP), ether extract (EE), ash, neutral detergent fiber (NDFom), acid detergent fiber (ADFom), non-protein N (NPN), Ca, P, Na, K, Cl, Mg, Fe, Cu and Se. In addition, in situ ruminal degradability and post-ruminal disappearance of dry matter (DM) and CP of the samples using a mobile bag technique were determined. Results indicate that the chemical composition of Kochia and Atriplex was notably different from those of Suaeda and Gamanthus. All of these halophytic plants had high concentrations of Na, K, Cl, Cu and Se, and low levels of Ca, P and Mg. The rapidly degradable fractions of DM and CP (g/g) of Kochia (0.31 and 0.35, respectively) and Atriplex (0.39 and 0.50, respectively) were lower than for Suaeda (0.53 and 0.55, respectively) and Gamanthus (0.56 and 0.66, respectively). Ruminal DM and CP disappearance of Kochia (444 and 517 g/kg, respectively) and Atriplex (472 and 529 g/kg, respectively) were lower (P<0.05) than those of Suaeda (553 and 577 g/kg, respectively) and Gamanthus (663 and 677 g/kg, respectively) (P<0.05) using the mobile bag technique. Suaeda had the lowest (P<0.05) NDFom and ADFom disappearance (214 and 232 g/kg, respectively) in the rumen. Kochia scoparia and Atriplex dimorphostegia have more beneficial chemical nutritive components and digestible values versus Suaeda arcuata and Gamanthus gamacarpus.

Ensiling and subsequent ruminal degradation characteristics of barley tea grounds treated with contrasting additives

The objective of this experiment was to determine the ensiling characteristics and in situ degradation of barley tea grounds (BTG) treated with contrasting additives. The BTG was ensiled without additive (control), or with mixtures of lactic acid bacteria and Acremonium cellulase (LAB + AUS), formic acid (FA), and sodium hydroxide (NaOH) for a period of 60 days. Three ruminal-fistulated steers were used to determine in situ degradabilities of dry matter (DM), crude protein (CP) in the BTG and its silages. In the LAB + AUS treated silage, the pH value (P<0.001) and ammonia-N content (P=0.007) were lower and the lactic acid content (P<0.001) was higher than the control. The FA and NaOH treated silages were well preserved as indicated by low ammonia-N content (P=0.007), no propionic acid and butyric acid. The LAB + AUS treated silage had higher rapidly degradable fraction of DM and CP than the control and BTG (P<0.001). The NaOH treated silage had higher contents of rapidly degradable fraction, slowly degradable fraction and effective degradability of DM and CP than control and BTG (P<0.01).

Effects of microwave irradiation on ruminal protein degradation and intestinal digestibility of cottonseed meal

The objectives of this study were to determine the effects of microwave irradiation on ruminal degradability and intestinal digestibility of crude protein (CP) and to monitor the fate of true proteins of cottonseed meal (CSM) in the rumen. Duplicate nylon bags of untreated or irradiated CSM (microwave power of 800 W for 2, 4 and 6 min) were suspended in the rumen of four non-lactating Holstein cows for up to 48 h, and resulting data were fitted to non-linear degradation model to calculate degradation parameters of CP. Proteins of untreated and treated CSM bag residues were fractionated by gel electrophoresis. Intestinal digestibility of CP was measured using the mobile nylon bag technique. From in situ results, microwave irradiation decreased ( P < 0.05) the water soluble fraction and degradation rate, but increased the potentially degradable fraction of CP. The effective degradability of CP decreased ( P < 0.05) as processing period increased. Irradiation for 2 and 4 min increased ( P < 0.05) intestinal digestibility of ruminally undegraded CP, but extending to 6 min lowered ( P < 0.05) the beneficial effect that 4 min had on intestinal CP digestibility. Electrophoretic results indicated that globulin 9S in untreated CSM (whereas globulin 9S, globulin 5S and albumin 2S in microwave irradiated CSM) make the bulk of escaped protein. Based upon these results, microwave irradiation at a power of 800 W for 4 min had the greatest potential to increase digestible undegraded protein.

Effects of gamma irradiation on protein degradation of soybean meal in the rumen

The aim of this study was to evaluate the effects of gamma irradiation (g-irradiation) at doses of 25, 50 and 75 kGy on ruminal dry matter (DM) and crude protein (CP) degradability and intestinal CP digestibility of soybean meal (SBM). Nylon bags of untreated or g-irradiated SBM were suspended in the rumen of four Holstein cows for up to 48 h, and resulting data were fitted to non-linear degradation model to calculate degradation parameters of DM and CP. From in sacco results, the water soluble fractions decreased linearly (P<0.001) and the potentially degradable fractions of DM and CP increased linearly (P<0.001) by g-irradiation. Effective degradability of DM and CP decreased linearly (P<0.001) with increases in irradiation dose. Gamma irradiation at doses of 25, 50 and 75 kGy decreased effective degradability of CP at rumen outflow rate of 0.05 h −1 by 17, 30 and 42%, respectively. Gamma irradiation increased linearly (P<0.001) intestinal mobile bag digestibility of ruminally undegraded CP. At doses of 25, 50 and 75 kGy, CP digestibility increased by 4, 15 and 23%, respectively. Electrophoretic analyses of untreated, 25, 50 and 75 kGy g-irradiated SBM protein residues revealed that two of the subunits of β-conglycinin (ά and α) were degraded completely after 2, 4, 8 and 12 h, respectively, whereas the β subunit of this protein was more resistant to degradation. In untreated SBM, the two subunits of glycinin (acidic and basic polypeptides) were degraded in the middle of the incubation period, but in 25, 50 and 75 kGy g-irradiated SBM, the acidic subunit of glycinin were degraded after 8, 12 and 24 h of incubation, respectively, and the basic subunit of glycinin were not degraded even after 48 h of incubation. In conclusion, SBM proteins appeared to be effectively protected from ruminal degradation by g-irradiation at doses higher than 25 kGy.

Effects of microwave irradiation on ruminal degradability and in vitro digestibility of canola meal

This study was completed to evaluate effects of 800 W microwave irradiation for 2, 4 and 6 min on ruminal dry matter (DM) and crude protein (CP) degradation parameters of canola meal (CM). Ruminal nylon bags of untreated or treated CM were suspended in the rumen of three Holstein steers for up to 48 h and resulting data were fitted to non-linear degradation model to calculate effective rumen degradation (ERD). Effective degradability of DM linearly (P<001) decreased as irradiation time increased. There was a linear decrease in the water soluble fraction and a linear increase in the potentially degradable fraction of CP (P<0.001). Microwave irradiation for 2, 4 and 6 min decreased ERD of CP at rumen outflow rate of 0.05 h −1 by 21, 24 and 29% units, respectively. Although there were differences for ERD of CP between treatments, there were not, in general, explained by polynomial orthogonal contrasts. Microwave irradiation for 2 and 4 min increased in vitro CP digestibility of ruminally undegraded CM at 8 and 12 h pre-incubation (linear effect, P<0.001) and 24 h pre-incubation (quadratic effect, P<0.001). Microwave irradiation for 6 min decreased in vitro digestibility of CP compared to 4 min. Electrophoresis results showed that napin sub-units of untreated CM disappeared completely within the shortest incubation period, whereas cruciferin sub-units were degraded in the middle of incubation period. In 4 min microwave irradiated CM, napin subunits were degraded in the middle of incubation and cruciferin subunits were degraded in the longest incubation period. In conclusion, CM proteins appeared to be effectively protected from ruminal degradation by a 4 min microwave irradiation.

Effects of microwave irradiation on ruminal protein and starch degradation of corn grain

This study was designed to evaluate effects of 800 W microwave irradiation for 3, 5 and 7 min on ruminal dry matter (DM), crude protein (CP) and starch degradation parameters of corn grain. Nylon bags of untreated or microwave treated corn were suspended in the rumen of three Holstein steers for 0–48 h, and resulting data were fitted to a non-linear degradation model to calculate effective rumen degradation (ERD). Microwave treatments decreased (P<0.05) the water soluble fraction and increased the potentially degradable fraction of CP, except for 7 min processing time that decreased (P<0.05) the potentially degradable fraction. Processing for 3 and 5 min had no effect, but for 7 min it decreased (P<0.05) ERD of CP. Microwave irradiation for 3 and 5 min increased (P<0.05) the water soluble fraction and decreased the potentially degradable fraction of starch. The degradation rate of the latter fraction increased (P<0.05) with 3 and 5 min processing times. Microwave irradiation for 7 min decreased (P<0.05) the water soluble fraction and the potentially degradable fraction of starch. Processing for 3 and 5 min increased (P<0.05), but for 7 min decreased (P<0.05) ERD of starch. From SDS-PAGE patterns, four major protein components in corn containing prolamin (i.e., zein), albumin, globulin and glutelin fractions were observed. Electrophoretic analysis of protein residues revealed that microwave processing decreased degradation of corn true protein. SDS-PAGE indicated that the bulk of the rumen undegradable protein for untreated corn was zein, while for 5 and 7 min microwave treated corn it was zein and other proteins. In this study, the optimal processing time with 800 W microwave power was judged to be 5 min.

Effects of microwave irradiation on ruminal degradation and in vitro digestibility of soya-bean meal

AbstractThis study was carried out to determine ruminal dry matter (DM) and crude protein (CP) degradation characteristics of untreated, 2-, 4- and 6-min microwave-treated soya-bean meal (SBM) by using nylon bags and sodium dodecyl sulphatepolyacrylamide gel electrophoresis (SDS-PAGE) techniques. Nylon bags of untreated or treated SBM were suspended into the rumen of three Holstein steers from 0 to 48 h, and data were fitted to non-linear degradation characteristics to calculate effective rumen degradation (ERD). There were significant differences (P &lt; 0·05) for DM and CP degradation parameters between untreated and microwave-treated SBM. Microwave treatments decreased the water-soluble fraction and increased the potentially degradable fraction of CP. The degradation rate of the latter fraction decreased with these treatments. As a consequence, microwave treatments decreased (P &lt; 0·05) ERD of CP. From densitometric scanning, SBM proteins were seen to be composed of two major components; β-conglycinin and glycinin, accounting for proportionately 0·30 and 0·40 of buffer-soluble SBM proteins, respectively. Electrophoretic analysis of untreated, 2-, 4- and 6-min microwave-treated SBM protein residues revealed that two of the subunits of β-conglycinin (α -and α) were degraded completely after 2, 4, 24 and 48 h, respectively, whereas the α subunit of this protein was more resistant to degradation. In untreated SBM, the two subunits of glycinin (acidic and basic polypeptides) were degraded in the middle of the incubation period, but in microwave-treated SBM were not degraded until 48 h of incubation. In vitro digestibility of ruminally undegraded CP of untreated and treated SBM increased (P &lt; 0·05) with increases in rumen incubation time from 8 to 24 h. In conclusion, SBM proteins appeared to be effectively protected from ruminal degradation by a 4-min microwave treatment. SDS-PAGE results indicated that ruminally undegraded protein from untreated SBM was mainly composed of the basic subunit of glycinin, whereas that from microwave-treated SBM was composed of β-conglycinin and both basic and acidic subunits of glycinin.

Chemical Composition and Ruminal Dry Matter and Crude Protein Degradability of Spineless Cactus

AbstractThe objective of this study was to determine ruminal degradability of the dry matter (DM) and crude protein (CP) of 10 varieties of spineless cactus (Opuntia spp.) grown in north‐eastern Brazil. Two ruminally fistulated steers were used in a randomized complete block design. Ash, CP, acid detergent fiber, and acid detergent lignin levels ranged from 10.4 to 13.3 %, 6.2–7.7 %, 19.8–24.8 % and 3.4–5.4 %, respectively. Relative to the other cactus varieties, Redonda had the highest (P &lt; 0.05) in situ soluble DM fraction and effective DM degradability. No differences in effective DM degradability were observed between the other cactus varieties. In situ soluble CP fraction ranged from 1.7 % of CP for the 69 IPA/UFRPE variety to 11.1 % of CP for the Gigante variety. Slowly degradable CP fraction and its rate of degradation were similar among the cactus varieties (average 90 % of CP and 9 % h−1, respectively). The cactus variety 69 IP/UFRPE had a lower (P &lt; 0.05) effective ruminal CP degradability (ECPD) than the other varieties, which had a similar ECPD (average 66 % of CP). It was concluded that differences in ruminal degradability exist between cactus varieties, with more variations observed for ruminal DM than for CP degradability.

In situ ruminal and intestinal nutrient digestibilities of mesquite ( Prosopis juliflora) pods

Two steers fitted with ruminal and duodenal cannulas were used in a randomized complete block design to determine ruminal and intestinal digestibility of dry matter (DM), crude protein (CP) and neutral detergent fiber (NDF) from as collected and dried (80 °C for 2 h) mesquite pods. On a DM basis, as collected mesquite pods contained 290 g kg −1 neutral detergent fibre, 172 g kg −1 acid detergent fibre, and 127 g kg −1 CP. Drying at 80 °C for 2 h reduced ( P<0.05) the in situ soluble CP fraction and increased ( P<0.05) the slowly degradable CP fraction and its rate of degradation. However, ruminal degradability of both CP and DM of mesquite pods were not affected by drying. Post-ruminally digestibility of ruminal undegraded CP and NDF were low and unaffected by drying. Total tract digestibility of DM, CP and NDF were similar for as collected and dried mesquite pods, averaging 68, 78 and 9%, respectively. It was concluded that the rumen is the main site of digestion of mesquite pods and that drying at 80 °C for 2 h had no adverse effects on their intestinal or total tract digestibilities.

Short Communication: Effect of Tannic Acid on Composition and Ruminal Degradability of Bermudagrass and Alfalfa Silages

We measured the effects of the addition of tannic acid on chemical composition and crude protein (CP) ruminal degradability of bermudagrass, cv. coast cross (Cynodon dactylon L.) and alfalfa (Medicago sativa L.) silages with nylon bags incubated in the rumen of two fistulated lactating cows. Silage pH was greater for alfalfa than for bermudagrass. The addition of tannic acid had no effect on silage pH. Ammonia N was greater in alfalfa than in bermudagrass silage. Treated and control silages had similar ammonia N concentrations. The percentage of CP that was solubilized at time 0 was lower for alfalfa than for bermudagrass silage. The addition of tannic acid decreased the portion of CP solubilized at time 0 and increased the potentially degradable fraction of CP. The potentially degradable fraction of CP was greater for alfalfa than for bermudagrass. There was an interaction of species and treatment; the disappearance rate of CP increased with tannic acid treatment of alfalfa but decreased with acid treatment of bermudagrass. The effective degradability of CP was similar for control and treated alfalfa but lower for treated than for control bermudagrass. Tannic acid treatment is effective in decreasing the rapidly soluble fraction of alfalfa and bermudagrass silages, which could be beneficial to the animal because it would decrease the excess of N in the rumen after feeding. Tannic acid treatment decreased CP degradability of bermudagrass silage but had no effect on alfalfa silage, suggesting that tannic acid concentration required to effectively decrease CP degradability differs among forages.

The nutritive value of hemp meal for ruminants

Hemp meal (HM) is derived from the processing of hemp (Cannabis Sativa L.) seeds. The objective of this study was to determine the nutritive value of HM for ruminants. Two ruminally fistulated cows were used in a randomized complete-block design to estimate in situ ruminal dry matter (DM) and crude protein (CP) degradability of HM relative to canola meal (CM), heated canola meal (HCM) and borage meal (BM) meal. Intestinal availability of rumen undegraded CP was estimated using a pepsin–pancreatin in vitro assay. Twenty growing lambs were utilized in a completely randomized design to determine total–tract nutrient digestibility coefficients of diets in which HM replaced CM at 0, 25, 50, 75 and 100% as a protein source. Results of the in situ study showed that the soluble-CP fraction of HM was similar to that of HCM and lower (P &lt; 0.05) than those of CM and BM. Rate of degradation of the potentially degradable CP fraction and effective CP degradability of HM was higher (P &lt; 0.05) than HCM and lower (P &lt; 0.05) than CM and BM. Rumen undegraded CP and intestinal digestibility of RUP were highest (P &lt; 0.05) for HM and HCM (average 782.5 and 644.5 g kg–1 of CP, respectively), intermediate for CM (473.9 and 342.9 g kg–1 of CP, respectively) and lowest for BM (401.5 and 242.3 g kg−1 of CP, respectively). However, total available CP was similar for the four protein sources (average 857.8 g kg−1 of CP). Feeding up to 200 g kg−1 HM did not affect voluntary intake or total-tract nutrient digestibility coefficients for sheep fed a barley-based diets. Hemp meal is an excellent source of RUP, with high post-ruminal availability, and may be used to replace CM with no detrimental effects on nutrient utilization by sheep. Key words: Hemp meal, nutritive value, ruminants