Effect of moist heat treatment on in-vitro degradability and ruminal escape protein and amino acids of mustard meal

A study was conducted to determine the effects of moist heat treatment (127°C, 117 kPa steam pressure) for 10 min on protein fractions and in-vitro crude protein (CP) degradability of mustard meal. Rumen undegraded protein (RUP) and amino acid disappearance of unheated, and heated, mustard meal were measured following 12 h of rumen incubation using two ruminally fistulated cows. Intestinal availability of RUP was estimated using an enzymatic (pepsin–pancreatin) procedure. Heat treatment reduced (p<0.05) protein solubility and increased (p<0.05) neutral detergent insoluble CP without affecting acid detergent insoluble CP of mustard meal. Relative to the control, heated mustard meal had a lower (p<0.05) effective in-vitro CP degradability (445.2 vs. 746.8 g kg⁻¹ of CP) and a higher (p<0.05) ruminal escape CP (615.1 vs. 120.2 g kg⁻¹ of CP) value. Amino acid composition was not affected by heat treatment except for the concentration of arginine and lysine which was lower (p<0.05) in heated than in unheated mustard meal. Disappearance of all amino acids following 12 h of rumen incubation was lower (p<0.05) in unheated than in heated mustard meal. Heat treatment increased (p<0.05) the amount of protein available for digestion in the small intestine from 75.7 to 518.1 g kg⁻¹ of CP. It was concluded that moist heating of mustard meal for 10 min will reduce ruminal CP and amino acid degradability without compromising the intestinal availability of ruminal undegraded protein.     

Nitrogen in vivo digestibility and in situ degradability data for estimation of lower tract N digestibility with or without correction for microbial contamination

In situ degradability and in vivo (by difference) digestibility trials were conducted to estimate lower tract residual N digestibility (LTRND) of five protein supplements. Efforts were also made to improve the in situ method of measuring protein degradability. For in situ degradability trials, soybean meal (SBM), corn gluten meal (CGM), cotton seed cake (CSC), wheat bran (WB) and corn gluten feed (CGF) were weighed into Dacron bags and incubated in the rumen of three cannulated Chios ewes. SBM, CGF and WB were degraded significantly, while CGM and CSC were least degraded. Microbial contamination (MC) resulted in a 5.3–28.3% artificially decrease in effective ruminal protein degradation of supplements. Total tract digestibility was measured using five rams in an in vivo, by difference, trial using a 5 × 5 Latin-square design. SBM had higher CP digestibility compared to WB, CGF and CSC, and higher N free extract (NFE) digestibility compared to the other feeds. CGM showed higher CP digestibility compared to WB, CGF or CSC, while CGF had higher organic matter (OM) and crude fibre (CF) digestibility compared to WB. CSC was the protein source with the lowest digestibility of OM, CP and NFE in comparison with the other feeds. LTRND was predicted as 0.928, 0.806, 0.227, 0.540, and 0.498 for SBM, CGM, CSC, WB, and CGF, respectively, or 0.931, 0.803, 0.147, 0.364, and 0.316 when the correction for MC was applied. Lower tract N digestibility could be predicted via a combination of in situ degradability and in vivo apparent digestibility data. This approach yields significant data regarding LTRND estimation of protein supplements, while diminishing animal suffering by avoiding small intestinal fistulation.     

Effects of vitreousness and particle size of maize grain on ruminal and intestinal in sacco degradation of dry matter,starch and nitrogen

We assessed the effects of vitreousness and particle size of maize grain on ruminal and intestinal in sacco degradation of dry matter, starch and nitrogen. Six maize grain (Zea mays) genotypes characterized by differing vitreousness (proportion of vitreous in total endosperm) were ground (3-mm screen; Gr, ground particles, mean particle size (MPS): 526 μm) and cracked with a roller mill using two gap width settings (CS, cracked small particles, MPS: 1360 μm; CL, cracked large particles, MPS: 2380 μm). The ruminal and intestinal in sacco degradation of dry matter, starch and nitrogen was measured on three dry Holstein cows, fitted with rumen, proximal duodenum and terminal ileum cannulas, fed maize silage ad libitum twice daily. The ruminal starch degradability and intestinal digestibility differed among genotypes (P<0.001) and decreased as particle size increased (P<0.001). For the same particle size, starch ruminal degradability decreased (P<0.05) and intestinal digestibility decreased (P<0.002) with vitreousness. Particle size and vitreousness of maize grain are efficient factors for manipulating the amount of starch escaping rumen degradation, but may be limiting for the amount of starch digested in the small intestine.     

Effect of rare earth elements on in vitro rumen microbial fermentation and feed digestion

The objectives of this study were to investigate the effects of rare earth elements (REEs) on in vitro rumen fermentation, gas production, microbial protein synthesis and nutrient digestion using in vitro batch culture and continuous culture technique. A mixture of REE containing (g/kg) 380 g of LaCI₃·6H₂O, 521 g of CeCI₃·6H₂O, 30 g of PrCI₃·6H₂O and 69 g chlorides of other light REEs. The experimental diet consisted of 885 g/kg barley grain, 84 g/kg barley silage and 31 g/kg supplement (dry matter (DM) basis). Diet supplemented with different dosages of REE (control, no additional REE; low, 400 mg/kg REE; and high, 800 mg/kg REE, DM basis) were incubated for 4, 8, 14 and 24 h in diluted rumen fluid. At the end of 24 h of incubation, gas production and concentration of volatile fatty acid (VFA) linearly increased with increasing REE supplementation; whereas, influence of REE supplementation on VFA profile was marginal. Dry matter disappearance was not affected (P>0.10). Six dual-flow continuous culture fermenters were used in a replicated 3 × 3 Latin square with same treatments and same diet used in the batch culture. Mean ruminal pH (5.71) and total VFA (93.6 mM) concentration were not affected by supplementation of REE. The molar proportion (mol/100 mol) of acetate (39.1) and propionate (50.5) was similar among the treatments. However, the proportion (mol/100 mol) of butyrate was higher with the high REE (6.6) than with low REE (5.3) or the control (5.8). Ruminal true digestibilities of organic matter (OM) (0.785, 0.811 and 0.828), acid detergent fibre (0.360, 0.431 and 0.432) and crude protein (0.496, 0.590 and 0.589) for control, low and high REE, respectively, linearly increased with increasing REE supplementation, whereas, the increase in ruminal digestibility from low to high dosage of REE was minimal. Microbial nitrogen (N) production (g/day) and microbial efficiency (g N/kg of truly fermented OM) were not affected by treatments. Improvement of ruminal digestibility of OM due to REE supplementation was attributed to the increase in digestibility of fibre and degradability of protein. The results suggest that REE supplementation improved ruminal fibrolytic and proteolytic activities.     

Nutritional characterization of Mucuna pruriens: 3. Effect of replacing soybean meal with Mucuna on intake,digestibility, N balance and microbial protein synthesis in sheep

Mucuna pruriens seeds have relatively high crude protein (CP) concentrations, but little is known about their potential to replace commonly used CP supplements in ruminant rations. The aim of this experiment was to determine effects of replacing soybean meal (SB) with Mucuna on the performance of lambs. Forty Rambouillet lambs (33.2 ± 5.73 kg) fed a basal diet of maize grain, cottonseed hulls and urea were randomly assigned to one of four supplements formulated by substituting 0 (SB), 330 (Lo), 670 (Med) or 1000 g/kg (Hi) of soybean meal with rolled Mucuna seeds. Lambs were housed individually in metabolic crates and allowed ad libitum access to isocaloric (metabolizable energy=11.7 MJ/kg dry matter, DM) and isonitrogenous (CP = 146 g/kg, DM) diets for 14 d of adaptation and 7 d of total fecal collection. Fecal egg counts and coccidian oocyst scores were determined on d 14. Dry matter intake (1.7 kg/d versus 1.5 kg/d; P<0.05), CP digestibility (774 g/kg versus 714 g/kg DM; P<0.05) and N retention (28.0 g/d versus 20.4 g/d; P<0.01) were higher and amylase-pretreated neutral detergent fiber digestibility (617 g/kg versus 686 g/kg DM) was lower (P<0.05) in sheep fed SB versus Mucuna diets. However, supplementary protein source did not affect rumen pH, blood urea N or glucose concentration, or fecal egg counts. Increasing the level of Mucuna supplementation increased (P<0.05) level and efficiency of microbial protein synthesis, ruminal fluid acidity, total volatile fatty acid concentration, decreased (P<0.05) coccidian oocyst scores, and tended (P<0.10) to increase N retention. Therefore, SB is a better supplement than Mucuna to support performance of lambs. Nevertheless, Mucuna seeds are a promising CP supplement for situations where cost or availability precludes use of SB in ruminant rations.     

Nutrient digestibility in Atlantic salmon and broiler chickens related to viscosity and non-starch polysaccharide content in different soyabean products

Total tract digestibility in Atlantic salmon and ileal digestibility in chicken were assessed from diets with different soyabean products (hulled, toasted, extracted, SBM; reduced oligosaccharide content, ROM; ethanol-extracted protein concentrate, SPC; isolated protein, ISP). The concentration of dietary fibre was highest in SBM and ROM, while it was low in ISP. In vitro viscosity was also higher in SBM than in the other soyabean products. The diets for the salmon and chickens were based on the same feed ingredients, with the exception that fish meal provided half the crude protein in the salmon diets. For each species, the diets were isonitrogenous, contained similar amounts of fat (fish oil), and were balanced with dextrin, thus substituting soyabean non-starch polysaccharides (NSP) and other non-proteinous components by dextrin.In the salmon, total tract digestibility of nitrogen and dry matter were lower (p < 0.05) with the SBM and ROM diets than with the ISP diet. In the chickens, ileal digestibility of dry matter differed among all treatments (p < 0.05). Digestibility of nitrogen, starch, phosphorus and calcium in the chickens was lower (p < 0.05) with the SBM diet than with the ISP and SPC diets, and fat digestibility was lower (p < 0.05) with the SBM and ROM diets than with the SPC diet. Also, the SBM diet gave lower (p < 0.05) digestibility of nitrogen, phosphorus and calcium than the ROM diet, while the ROM diets gave lower (p < 0.05) digestibilities of nitrogen, fat and starch than the ISP and SPC diets. Intestinal viscosity was higher (p < 0.05) and cholesterol content in the blood was lower (p < 0.05) for the chickens fed the SBM-based diet than those fed the other diets. There was a similar response to the different soy products in salmon and chickens with regard to digestibility of nitrogen and fat (p < 0.05). The negative effects of soyabean meals with a low protein content could indicate antinutritive effects of NSP fractions in soyabean meal, as indicated by the elevated viscosity and the decrease in blood cholesterol content.     

Effects of considering the rate of comminution of particles and microbial contamination on accuracy of in situ studies of feed protein degradability in ruminants

Ruminal degradation of dry matter (DM) and crude protein (CP) in samples of soybean meal (SBM), barley grain (BG) and lucerne hay (LH) were measured by an in situ ruminal technique considering either only the outflow rate of particles from the rumen (k_p) or, both k_p and rate of particle comminution (k_c). The effect of correction for the microbial contamination using an ¹⁵N technique was also determined for LH. Degradation and transit studies were completed on three wethers cannulated in the rumen and duodenum and fed a mixed diet of LH and concentrate (2:1 on DM), at an intake level of 50 g DM/kg BW^0.75. Transit studies of concentrates and forages were completed with SBM and LH samples marked with Yb and Eu, respectively. Mean values of k_c were higher in SBM than in LH (0.357 versus 0.204 h, P < 0.05). The same trend was observed for k_p (0.0587 versus 0.0452/h; P < 0.1). Apparent estimates of the proportion of rumen undegraded CP obtained using both rates were 0.884, 0.745 and 0.825 of those obtained using only k_p (0.535, 0.247 and 0.303 for SBM, BG and LH, respectively). Differences occurred for SBM and LH (P < 0.01) and for BG (P < 0.05). The pattern of microbial contamination of LH, expressed as a proportion of residual DM or CP, fitted exponential curves with asymptotic values of 0.076 and 0.586, respectively. Correction for microbial contamination reduced (P < 0.05) estimates of undegraded CP from 0.303 to 0.238, which was further reduced to 0.178 (P < 0.01) when the effect of k_c was also considered.     

Effects of exogenous enzymes on in vitro gas production kinetics and ruminal fermentation of four fibrous feeds

This study was conducted to investigate effects of increasing doses: 0 (control), 6 (low), 12 (medium) and 24 (high) mg/g DM of ZADO^® enzyme preparation mixture (ENZ) on in vitro gas production (GP) and some ruminal fermentation parameters of the fibrous feeds Saccharum officinarum (leaves), Andropogon gayanus (leaves), Pennisetum purpureum (leaves) and Sorghum vulgare (straw). Rumen liquor was obtained from two Brown Swiss cows fitted with permanent rumen cannulae fed a total mixed ration of a 500:500 commercial concentrate and alfalfa hay ad libitum. The GP was recorded at 2, 4, 6, 8, 10, 12, 24, 48, 72 and 96 h of incubation. After 96 h, the incubation was stopped and the pH of the mixture was determined and filtrate used to determine dry matter degradability (DMD), partitioning factor (PF₉₆), gas yield (GY₂₄), in vitro organic matter digestibility (OMD), metabolizable energy (ME), short chain fatty acids (SCFA), and microbial crude protien production (MCP). In general, the crude protein (CP) content of the fibrous feeds was low and ranged from 23 g/kg DM (S. officinarum) to 44 (A. gayanus). The fibre contents (i.e., NDFom and ADFom) were highest (P<0.05) in S. officinarum. Increasing ENZ dose linearly increased (P<0.05) GP of all fibrous feeds and had a quadratically increased (P<0.05) asymptotic gas production in P. purpureum and S. vulgare and rate of gas production in S. officinarum and S. vulgare. Addition of ENZ also quadratically increased (P<0.05) GP at all incubation times in S. officinarum and S. vulgare, and A. gayanus, but only at 72 h in A. gayanus. The parameters of ruminal fermentation of OMD, ME, GY₂₄ and SCFA linearly increased (P<0.05) and MCP linearly decreased (P<0.05) with the ENZ addition. Addition of enzyme affected ruminal fermentation of our feeds differently, mainly dependent on their fibre content, although dosage of enzyme was also important as impacts generally increased at higher dosages of ENZ.     

Dependence of forage quality and methanogenic potential of tropical plants on their phenolic fractions as determined by principal component analysis

This study was conducted to elucidate relationships among various phenolic fractions in, and methane (CH₄) emissions from, tropical plants when incubated in ruminal fluid in vitro. As a second objective, principal component analysis (PCA) was tested for its utility in screening plants for their ability to reduce CH₄ formation at simultaneously acceptable nutritional quality. Leaves from 27 tropical plants were analyzed for their nutritional composition and various phenolic fractions. They were incubated in vitro using the Hohenheim gas test method. Variables measured after 24 h of incubation were total gas and CH₄ production, and pH, ammonia, bacterial and protozoal counts, as well as short-chain fatty acids in the incubation fluid. In vitro organic matter (OM) digestibility was computed by a standard equation. The data obtained was subjected to analysis of variance, correlation, regression and PCA. Among phenolic fractions, total phenols had the closest relationship with CH₄/digestible OM (r = ?0.84, P<0.001). The total tannin fraction contributed strongly to this effect (r = ?0.74, P<0.001) whereas the non-tannin phenol fraction was less important (r = ?0.45, P<0.05). Methane reduction by the influence of non-tannin phenols was not associated with a negative effect on protein degradation, while this was the case with tannins. Condensed (r = ?0.60, P<0.01) and hydrolysable tannins (r = ?0.60, P<0.01) contributed to the decrease in CH₄/digestible OM. The loading plot of PCA showed that dietary crude protein (CP) content and incubation fluid ammonia, total short-chain fatty acids, propionate, valerate, iso-butyrate, iso-valerate as well as in vitro OM digestibility were clustered. They had inverse directions to contents of fiber fractions and incubation fluid acetate proportion and acetate-to-propionate ratio. The methane-to-total-gas ratio had the opposite effect of the contents of any phenolic fraction. Plants possessing a favorable forage quality, based on the corresponding PCA score plot, were Carica papaya, Manihot esculenta, Morinda citrifolia, Sesbania grandiflora and Melia azedarach, whereas CH₄ mitigating plants included Swietenia mahagoni, Acacia villosa, Eugenia aquea, Myristica fragrans and Clidemia hirta. All phenolic fractions studied reduced CH₄ emissions from in vitro incubations with ruminal fluid and PCA seems useful to screen plants for high nutritional quality and low ruminal CH₄ formation. However, high forage quality seemed to be partially associated with high CH₄ emission. The search for plants rich in non-tannin phenols might be promising as these compounds appear to decrease CH₄ while they obviously have less negative effect on protein degradation as compared to the tannin fractions.     

Chemical characterization,in vitro dry matter and ruminal crude protein degradability and microbial protein synthesis of some cowpea (Vigna unguiculata L. Walp) haulm varieties

A study was carried out to evaluate the chemical composition, in vitro apparently and truly degraded dry matter (DM), utilizable crude protein at the duodenum (uCP) (total CP at the duodenum minus endogenous CP), methane production, and short chain fatty acid production of haulms of six cowpea varieties. The study was arranged in a 2 × 2 × 2 factorial design, with three replicates. Three improved (ITA2, ITA6 and ITA8) and three commercial (Oloyin, Peu and Sokoto) cowpea varieties harvested during wet and dry seasons were used for the study. After an initial gas test to evaluate 96 h gas production profiles of haulms with and without polyethylene glycol (PEG), the time to half maximal gas production was calculated and a second incubation conducted with fermentation stopped at substrate specific half time (t_1/2) and 24 h for each substrate. True DM degradability was measured from incubated residues and combined with gas volume to estimate the partitioning factor. Crude protein flow to the duodenum was estimated by combining gas volume with the measured ammonia nitrogen in the incubated fluid. Addition of PEG did not have any effect (P>0.05) on all the variables determined. Interaction between group (improved vs. commercial) and season was observed for CP (P=0.002), lignin (P=0.003) and hemicellulose (P=0.030) contents of the haulms. A group × season interaction was also observed for some of the variables at both substrate specific t_1/2 and 24 h. Commercial cowpea haulms had greater (P=0.002) microbial mass and produced less (P<0.05) methane than the improved cowpea haulms. The improved cowpea haulms were less (P<0.001) degraded in the rumen and as a result ensured greater (P<0.001) amount of uCP. The results validated that cowpea haulm is an important agro-based by-product that is adequate in protein and energy to sustain ruminant animal production in Nigeria and other Sub-Saharan African countries during the extended dry season.     

In vitro estimations of the rate and extent of ruminal digestion of starch-rich feed fractions compared to in vivo data

An experiment was conducted to study the rumen digestion characteristics of whole feeds (WF) and the neutral detergent fibre (aNDF) and neutral detergent soluble (NDS) fractions of a range of starch-rich feeds using an automated in vitro gas production (GP) technique. In addition, the ruminal digestibility values predicted from the GP data were compared to previously acquired in vivo data. Nine feeds with starch concentrations ranging from 389 to 712 g/kg dry matter and with known in vivo digestibilities were subjected to neutral detergent extraction. The GP for each WF and the corresponding aNDF fractions were measured in duplicate in buffered rumen fluid during 72 h on two occasions. The fermentation residues were collected and analyzed for aNDF concentration to estimate their true organic matter (OM) and NDF digestibility. The GP from the NDS fraction was calculated by subtracting the GP from the aNDF fraction from the GP of the WF. A three-pool Gompertz model was fitted to the GP profiles (R² = 0.99) and a two compartment, mechanistic and dynamic rumen model was used to predict the digestibility of the potentially digestible feed fraction and the effective digestion rate (k_d). The true OM and NDF digestibility determined for the WF ranged from 0.804 to 1.011 and from 0.362 to 1.107, respectively. The NDF digestibility determined for the aNDF fraction ranged from 0.410 to 0.985. The effective k_d values estimated using GP data varied from 0.118 to 0.282/h for the WF and from 0.123 to 0.301/h for the NDS fraction, and were less (P<0.05) for maize compared to small grains (SG) but did not differ between barley and wheat (P>0.05). The effective k_d values for the aNDF fraction ranged from 0.039 to 0.082/h and did not differ (P>0.05) either between maize and SG or between barley and wheat. The predicted ruminal NDS digestibility determined using GP data closely matched the in vivo data describing starch digestion (R² = 0.81). The effective k_d values for the WF were strongly related (R² = 0.94) to those for the NDS fractions. The results indicate that when measured with the GP technique, the differences in the digestion characteristics of maize and small grains are less than those previously reported in studies using the in situ method. It is concluded that the predicted NDS digestibility determined using GP data corresponded well to the in vivo starch digestibility. Our results also suggest that the first order digestion rates of NDS (starch) in starch-rich feeds can be accurately determined by incubating WF samples in the GP system and using the GP kinetic data in a dynamic, mechanistic rumen model.     

In vivo and in situ digestibilities and nitrogen balance of Buddleia skutchii as a sole component and mixed with Pennisetum clandestinum in sheep diets

The objective of this work was to evaluate the intake (I) of all Buddleia skutchii foliage (BSF), collected from three different sites (places: A, B and C) in feeding sheep (phase 1), and in combination with Pennisetum clandestinum (Pc) (phase 2). Trials of feed intake, in vivo dry matter digestibility (IVDMD), and digestibilities of crude protein (CP), acid detergent fiber (ADF), neutral detergent fiber (NDF), and nitrogen balance were carried out during phase 1. Diet was given to nine Creole male lambs of 23(±3) kg body weight (BW), located in individual metabolism crates. During phase 2, four treatments were evaluated (T1 = 100% Pc, T2 = 20% BSF + 80% Pc, T3 = 40% BSF + 60% Pc and T4 = 60% BSF + 40% Pc) in a 4 × 4 Latin square design, using four ruminal cannulated Creole male rams of 50 ± 2 kg BW and remained in individual metabolism crates. In vivo digestibility (DM, CP and gross energy (GE)) and kinetics of in situ disappearance of DM were evaluated. The results in phase 1 indicated that BSF from Site B had relatively higher CP (14.9%), ADF (50.6%) content and nitrogen retention (1.93 g d⁻¹). On the other hand, the lambs showed intake levels of 376.29 g d⁻¹ DM, 56.21 g d⁻¹ CP, 206.24 g d⁻¹ ADF and 1418.21 kcal gross energy (P > 0.05); and digestibilities of 54.23% DM, 47.17% CP and 39.31% NDF. Therefore, BSF from Site B was selected for the second phase of this work as the best result. We observed that the nutrition quality of the diets was higher as a result of increasing BSF concentration in the diet. When sheep were fed on 40% BSF–60% Pc, DM intake levels of 900.6 g d⁻¹, and DM, CP and GE digestibility of 70.0, 52.82 and 55.1%, respectively, were observed. There were not significant differences among diets, and in situ disappearance, K_d and K_p, but the diet with 60% of BSF presented higher ruminal digestibility (42.3%). The results allowed to validate the local knowledge on BSF as a promising forage species, and showed that BSF should be incorporated in a sheep production system.     

Evaluation of a two-stage in vitro technique for estimating digestibility of equine feeds using horse faeces as the source of microbial inoculum

To develop a two-stage in vitro technique that simulates both pre-caecal and hind gut digestion processes, four enzymatic pre-digestion treatments by pepsin and α-amylase (ET0 = control, ET1 = 2 h pepsin + 2 h amylase, ET2 = 2 h pepsin + 4 h amylase, ET3 = 8 h pepsin + 16 h amylase) were tested on oat hay (OH), barley grain (BG) and soybean meal (SBM). Investigated parameters were enzymatic organic matter digestibility (OMDe), and gas production (G48h, G72h) and OM digestibility (OMD) using horse faeces as a source of microbial inoculum.Enzymatic pre-digestion treatments affected (P<0.05) investigated parameters and their ranking differed among feeds. Only OMD of BG and SBM were higher after the pre-digestion treatment. OMD prior to (ET0) and after ET3 application were, successively, 0.357 versus 0.351 (OH), 0.71 versus 0.79 (BG) and 0.70 versus 0.78 (SBM). Net gas production overestimated fermentation potential of non-pre-digested feeds. G72h (ml/g DM) prior to (ET0) and after ET3 application were, successively, 80.3 versus 58.0 (OH), 151.7 versus 30.4 (BG) and 110.6 versus 37.7 (SBM).It was concluded that the enzymatic pre-digestion treatments effects varied among tested feeds, and that the suggested procedure be extended and validated with a large array of feeds of known digestibility values.     

The interaction between lactose level and crude protein concentration on piglet post-weaning performance,nitrogen metabolism,selected faecal microbial populations and faecal volatile fatty acid concentrations

A performance study and a nitrogen balance study (2×3 factorial) were conducted to investigate the interaction between lactose level (215 and 125 g/kg) (lactofeed 70; 860 g whey permeate/kg, 140 g soya bean meal/kg, Volac International, UK) and crude protein (CP) concentration (160, 185 and 210 g/kg) on post-weaning piglet performance, nitrogen metabolism, faecal microbiology and faecal volatile fatty acid concentrations. In the performance trial, 252 piglets (7.6 kg; 33 days of age) were assigned to one of six dietary treatments following a 12-day period on a commercial creep diet (17 MJ/kg DE, 16 g lysine/kg). The experimental diets were fed for 28 days (days 12–40) and were formulated to have identical digestible energy (15 MJ/kg) and total lysine (14.5 g/kg) contents. In the N balance experiment, 24 boars (20 kg live weight) were offered the same diets as in the performance trial. Faecal samples were collected for selected microbial populations. There was an interaction (P<0.05) between lactose and CP concentration in daily gain (ADG) and daily feed intake (ADFI) (P<0.01) during the weaner period (days 12–40). At the high lactose level there was a linear increase in ADG and ADFI with increasing CP. However, at the low lactose level there was no increase in ADG or ADFI above the medium CP. Pigs offered 215 g lactose/kg had a higher dry matter (P<0.001), organic matter (P<0.001), energy (P<0.001), nitrogen (P<0.01) and neutral detergent fibre (P<0.05) coefficient of total tract apparent digestibility compared to pigs offered 125 g lactose/kg. There was an interaction between lactose and CP concentration for nitrogen intake (NI) (P<0.05), urine pH (P<0.05) and selected faecal microbial populations. At the high CP level, pigs offered diets containing 215 g lactose/kg had a higher NI and a lower urine pH than pigs offered 125 g lactose/kg (P<0.05). However, the inclusion of lactose had no significant effect on either NI or urine pH at the low or medium CP concentration. At the low lactose level there was a linear increase in faecal E. coli population and a linear decrease in faecal Lactobacilli population with increasing CP. However at high lactose levels CP concentration had no effect on either E. coli or Lactobacilli populations. Pigs offered 215 g lactose/kg had a significantly higher Bifidobacteria population compared to pigs offered 125 g lactose/kg. There was a linear decrease in Bifidobacteria population as CP increased. In conclusion, at the high lactose level there was a linear increase in ADG and ADFI with increasing CP concentrations. There was no increase in these parameters above 185 g CP/kg at the low lactose level.     

Effect of elemental nano-selenium on feed digestibility,rumen fermentation,and purine derivatives in sheep

The objective of this experiment was to study the effect of elemental nano-selenium (NS) on feed digestibility, rumen fermentation, and urinary purine derivatives in sheep. Eight male ruminally cannulated sheep (42.5 ± 3.2 kg of body weight, BW) were used in a replicated 4×4 Latin square experiment in four 20 day periods. Depending on treatment designation, sheep were fed the basal diet supplemented with 0 (control), 0.3, 3 and 6 g of nano-Se/kg dry matter (DM). Ruminal pH (range of 6.68–6.80) and ammonia N concentration (range of 9.95–12.49 mg/100 mL) was decreased (P<0.01), and total VFA concentration (range of 73.63–77.72 mM) was increased linearly (P<0.01) and quadratically (P<0.01) with increasing nano-Se supplementation. The ratio of acetate to propionate was linearly (P<0.01) and quadratically (P<0.01) decreased due to the increasing of propionate concentration. In situ ruminal neutral detergent fiber (aNDF) degradation of Leymus chinensis and crude protein (CP) of soybean meal were linearly (P<0.01) and quadratically (P<0.01) improved by feeding nano-Se. Similarly, nutrients digestibility in the total tract and urinary excretion of purine derivatives were also quadratically (P<0.01) changed by increasing nano-Se supplementation. The present results indicated that nano-Se supplementation in basal diet improved rumen fermentation and feed utilization. Nano-Se could also stimulate rumen microbial activity, digestive microorganisms or enzyme activity. The optimum dose of nano-Se was about 3.0 g/kg dietary DM in sheep.     

Intake,digestibility and nitrogen utilization of Robinia pseudoacacia foliage fed to growing goat wethers

Black locust (BL; Robinia pseudoacacia L.), a native tree of southeastern USA known to contain substantial levels of condensed tannins (CT), was fed to 32, 4 month old (20.4 kg BW) Boer cross wether goats in two randomized complete block design trials. The objectives were to examine the effects of feeding hay diets containing several levels of fresh BL foliage on intake, digestibility, and N metabolism. First year (1999) diets were H_E (100% Eastern gamagrass [EGH; Tripsacum dactyloides L.] hay), H_EG (70% EGH and a 30% mixture of 59% ground corn [GC; Zea mays L.], 36% soybean meal [SBM; Glycine max L.], and 5% minerals), 25BL99 (75% EGH and 25% BL leaves), and 50BL99 (50% EGH and 50% BL leaves). Second year (2000) diets were H_O (100% orchardgrass [OGH; Dactylis glomerata L.] hay), H_OG (70% OGH and a 30% mixture of 63% GC, 37% SBM, and 5% minerals), 50BL00 (50% OGH and 50% BL leaves), and 75BL00 (25% OGH and 75% BL leaves). In 1999, apparent digestibilities of the diets in the order listed above were 62.4, 68.2, 58.0, and 60.6% (P = 0.001) for DM and 62.8, 72.5, 56.0, and 59.1% (P = 0.001) for crude protein (CP). Acid detergent lignin digestibilities were negative for diets 25BL99 (−56.7%) and 50BL99 (−49.3%), apparently due to the formation of insoluble tannin and lignin complexes during passage through the digestive tract. Intakes of DM were similar across diets. In 2000, apparent digestibilities of diet DM (64.4, 71.7, 64.8 and 65.4%) and CP (70.0, 76.0, 66.6, and 66.5%) did not differ. Lignin digestibilities were positive for diets 50BL00 (9.4%) and 75BL00 (29.6%) unlike those for year 1999. Overall, BL contained 10% CT and 18–34% hydrolyzable tannins. In 1999, N intake, urinary N (UN) excretion and N retained were higher for diet H_EG (P = 0.01) than diet H_E whereas fecal N excretion (FN) was similar for diets H_EG, 25BL99 and 50BL99. In 1999, FN excretion as a percentage of N intake was higher (P < 0.02) in the BL diets, although UN as a percentage of N intake did not differ among diets. In 2000, N intake and FN output were higher for BL diets compared to diets H_O (P = 0.01) and H_OG (P = 0.02). Fecal N as a percentage of N intake was lower (P = 0.01) for diet H_OG (24.0%) than for diets 50BL00 (33.4%) and 75BL00 (33.5%). Conversely, urinary N as a percentage of N intake was higher for diets H_O and H_OG compared to the BL diets (P = 0.02). Increased levels of dietary BL increased FN, suggesting that tannins formed insoluble protein complexes thus hindering digestibility.     

Intake and digestion by lambs of dwarf elephant grass (Pennisetum purpureum Schum. cv. Mott) hay or hay supplemented with urea and different levels of cracked corn grain

This study was carried out to evaluate intake, digestibility, ruminal fermentation, nitrogen (N) retention and ruminal microbial protein synthesis in lambs fed dwarf elephant grass (Pennisetum purpureum Schum. cv. Mott) hay or hay supplemented with urea and 0, 5, 10 or 15 g/kg of live weight (LW) of cracked corn grain. Ten lambs (mean LW of 28 ± 0.9 kg), housed in metabolic cages, were used in a double 5 × 5 Latin Square experiment. Except fibre intake and digestibility, which was higher, the intake and digestibility of the others feed components, as well as ruminal microbial protein synthesis and N retention were lower in non-supplemented lambs. Corn supplementation increased total dry matter (DM) (P<0.05), organic matter (OM), non-structural carbohydrate (NSC) and energy intake (P<0.01) but decreased total neutral detergent fibre (aNDFom) (P<0.01) intake, as well as OM and aNDFom intake from the hay (P<0.01). Apparent DM, OM and energy digestibility, as well as OM true digestibility (OMTD) increased (P<0.01), and aNDFom digestibility decreased linearly (P<0.01) as corn supplementation increased. Total N intake was not influenced but, apparent and true N digestibility, as well as urinary N excretion decreased (P<0.01), and ruminal microbial N entering the small intestine increased linearly (P<0.01) as corn supplementation increased. However, the efficiency of ruminal microbial protein synthesis was similar for all treatments. Mean ruminal pH values and ammonia N concentrations decreased linearly (P<0.01) with level of corn supplementation. Ammonia N and amino acid, as well as peptide concentrations in ruminal fluid were quadratically related (P<0.01) with the time after feeding. Corn supplementation had a linear additive effect on total dry matter and digestible energy intake, as well as on N retention, but a linear negative effect on hay intake and on fibre digestibility. However, decreased forage digestibility by animals was probably neither related to lower ruminal pH, which values were always higher than 7.0, nor related to ruminal sugar concentrations, which were similar for all treatments.     

Influence of condensed tannins from Brazilian semi-arid legumes on ruminal degradability,microbial colonization and ruminal enzymatic activity in Saanen goats

The present study aimed at determining the influence of condensed tannins present in the Brazilian legume species Mimosa hostilis, Mimosa caesalpinifolia and Bauhinia cheilantha on ruminal degradability, microbial colonization and enzymatic activity. Polyethylene glycol (PEG) was used to reduce the astringency and concentration of soluble condensed tannins. Four ruminally-cannulated Saanen goats (60 ± 8 kg BW) were fed, in two experimental periods, with a hay diet based on the studied legumes treated or non-treated with PEG. Voluntary intake, microbial colonization, DM, CP, NDF, and ruminal degradability of PEG treated and non-treated forage leaves, as well as pH, ammonia and 1,4 β-endoglucanase activity of the rumen content were evaluated. Astringency and soluble tannin concentration of the studied legumes were reduced by approximately 70% and 50%, respectively, with PEG treatment. Average DM intake was higher for the treated diet (16.76 g DM/kg BW/day against 13.06 g DM/kg BW/day). Percentile values for degradation parameters and for potential and effective degradabilities of DM, CP and NDF were also affected by the tannins, but at different intensities. Electron microscopic observations of ruminally-incubated legume leaves showed a more effective microbial colonization of PEG-treated leaves for all legume species. A decrease in pH and an increase in ammonia concentration and in endoglucanase activity in the ruminal content was also observed for PEG-treated diets at all sampling periods. Condensed tannins of the studied legume species have influenced the adhesion conditions, colonization and enzymatic activity of the microbial ecosystem, and consequently the ruminal degradation of the different dietary fractions. For this reason, the reduction in condensed tannin would be of great importance to improve the nutrition of ruminant feeding of these species.     

Supplementation of isonitrogenous oil seed cakes in cactus (Opuntia ficus-indica)–tef straw (Eragrostis tef) based feeding of Tigray Highland sheep

The experiment was conducted at Maichew Agricultural Technical Vocational Education and Training College, Ethiopia. Twenty four male yearling Tigray Highland sheep with mean body weight (BW) of 21 ± 2.6 kg (mean ± S.D.) were used to investigate the effect of different protein sources on feed intake, nutrient digestibility, BW change and carcass parameters in a study comprising of 90 days feeding trial, followed by 7 days of digestibility trial and evaluation of carcass parameters. Six individually fed animals were used per treatment in a randomized complete block design. The treatments consisted of ad libitum feeding of tef (Eragrostis tef) straw plus 172 g dry matter (DM) of cactus (Opuntia ficus-indica) pear (T1, control) and supplementation with 145 g DM cotton seed cake (CSC) (T2), 195 g DM noug seed cake (NSC) (T3) or 149 g DM peanut cake (PNC) (T4) per head per day. The quantity of the supplements was set to supply 62.5 g crude protein (CP). Tef straw DM intake was depressed (P<0.01) as the result of NSC supplementation. Sheep supplemented with CSC and PNC had higher (P<0.001) total DM intake than the control and NSC supplemented ones. Supplementation with NSC and PNC also resulted in higher (P<0.01) apparent digestibility of DM and OM compared to the control treatment. Supplementation with CSC and PNC resulted in better daily BW gain (P<0.001), feed conversion efficiency (FCE) and dressed carcass weight (P<0.01) compared to the non-supplemented diet. Dressing percentage on slaughter weight base was higher (P<0.01) in supplemented sheep than in the non-supplemented ones. Supplementation with PNC also promoted higher (P<0.05) rib-eye muscle area than in the non-supplemented ones. It was concluded that supplementation with 145 g DM CSC and 149 g DM PNC resulted in better feed intake, BW gain and carcass traits in cactus–tef straw based feeding of sheep.     

Rumen degradable nitrogen requirements for optimum microbial protein synthesis and nutrient utilization in sheep fed on finger millet straw (Eleucine coracana) based diet

Studies were conducted to determine the rumen degradable nitrogen (RDN) requirement levels for optimum microbial protein synthesis and nutrient utilization in Nellore rams fed on finger millet straw (FMS) based diet. Thirty six Nellore sheep were randomly divided into four groups of nine animals each using the balanced completely randomized design. Animals in all the groups were fed finger millet straw as a basal roughage and groundnut cake (GNC) was offered daily in two equal halves in the morning (8.00 AM) and evening (4.00 PM) as RDN source. The animals in group I (GI) were fed with ad libitum FMS. Animals in group II, III and IV (GII, GIII, and IV) were offered GNC @ 12.4, 16.6, and 21.1 g RDN/kg digestible organic matter (DOM) along with FMS. The daily total dry matter (DM) and organic matter (OM) intakes linearly increased (P<0.05) with increasing level of RDN supplementation while there was no difference in total DM and OM intake/kg W^0.75 among different experimental groups. The digestibility coefficients of DM (P<0.001), OM (P<0.001), crude protein (CP) (P<0.001), ether extract (EE) (P<0.001), neutral detergent fibre (NDF) (P<0.01) and acid detergent fibre (ADF) (P<0.03) increased quadratically with increasing level of RDN supplementation from GI to GIV. The purine derivatives (PD) excretion, microbial purine absorption and microbial nitrogen supply (MNS g/day) linearly increased (P<0.001) as the level of RDN supplementation increased. There was no difference in nitrogen capture efficiency (NCE) and microbial nitrogen to total urinary nitrogen ratio (MN:UN) among the RDN supplemented groups. This study indicated that 12 g RDN/kg digestible organic matter intake (RDN g/kg DOMI) or 18 g RDN/kg OM apparently digested in the rumen (RDN g/kg DOMR) may be adequate for optimum microbial protein synthesis and digestibility of nutrients, there by improved plane of nutrition in sheep fed on finger millet straw based diet.