Total Volatile Fatty Acid Levels Research Articles

The Effect of Saponite Clay on Ruminal Fermentation Parameters during In Vitro Studies.

Reducing the emission of global warming gases currently remains one of the strategic tasks. Therefore, the objective of our work was to determine the effect of saponite clay on fermentation in the rumen of cows. The pH, total gas production, CH4, and volatile fatty acid (VFA) production in ruminal fluid was determined in vitro. Saponite clay from the Tashkiv deposit (Ukraine) has a high content of silicon, iron, aluminum, and magnesium. The addition of 0.15 and 0.25 g of saponite clay to the incubated mixture did not change the pH but reduced the total production (19% and 31%, respectively) and CH4 (24% and 46%, respectively) in the ruminal fluid compared to the control group and had no significant effect on the total VFA levels, but propionic acid increased by 15% and 21% and butyric acid decreased by 39% and 32%, respectively. We observed a decrease in the fermentation rates, with a simultaneous increase in the P:B ratio and an increase in the fermentation efficiency (FE) in the groups fermented with saponite clay, probably a consequence of the high efficiency in the breakdown of starch in the rumen. Therefore, further in vivo studies to determine the effective dose and effect of saponite clay on cow productivity and the reduction of gas emissions are promising and important.

Comparative Analysis of In Vitro Fermentation Parameters in Total Mixed Rations of Dairy Cows with Varied Levels of Defatted Black Soldier Fly Larvae (Hermetia illucens) as a Substitute for Soybean Meal

In this study, we compared the digestibility levels and in vitro fermentation parameters of total mixed rations (TMRs) containing 20% and 40% defatted black soldier fly (Hermetia illucens) larvae (BSF) as a substitute for soybean meal (SBM) in the basal ration (60% roughage/40% concentrated feed) of dairy cows. We evaluated the volatile fatty acid (VFA), total gas production, methane emission, ammonia, pH, carbon dioxide, in vitro dry matter digestibility (IVDMD), and neutral detergent fiber digestibility (IVNDFD) of the TMR0 (basal), TMR20 (20% BSF included), and TMR40 (40% BSF included) diets at the end of 24 and 48 h of incubation. Significantly lower levels of ammonia formation were found in the TMR20 and TMR40 groups at 24 and 48 h (p < 0.001). An increase in total VFA levels was observed in the TMR0 group at 24 h (p < 0.001). The highest IVDMD was determined in TMR20 and TMR40 at 24 h. The highest IVNDFD value was observed in TMR20 at 24 h and in TMR40 at 48 h. The substitution of 20% and 40% of SBM with BSF positively affected IVDMD and IVNDFD (p < 0.001). TMR20 and TMR40 had the highest cumulative gas production at 48 h of incubation (p < 0.05). In conclusion, the use of BSF had a positive impact on digestibility and in vitro rumen fermentation. Therefore, we recommend the use of BSF in formulating dairy cow rations.

Meta-analysis of Saccharomyces cerevisiae on enhancement of growth performance, rumen fermentation and haemato-biochemical characteristics of growing goats

The use of Saccharomyces cerevisiae (SC) feed additives to improve animal performance are on the increase; however, the results of the action of SC supplementation on goats performance indices are conflicting. Thus, the thrust of this meta-analysis was to examine the influence of dietary SC intervention on the growth performance, haemato-biochemical indices and ruminal fermentation characteristics of growing goats fed total mixed ration (TMR). The search conducted in Google Scholar, PubMed and Scopus databases using several keywords yielded 500 studies of which 16 full-text articles were utilised for study. Response variables were aggregated via a random-effects model. The results showed that goats fed SC experienced higher average daily gain (ADG) than the controls (as standardized mean difference, SMD = 2.14; 95% confidence interval, CI: 1.40 to 2.89). In converse, dietary SC intervention had a small impact on dry matter intake (DMI) and feed conversion ratio (FCR). Subgroup analysis demonstrated that SC type (active vs inactive) improved FCR and ADG in growing goats. Results suggested that SC preparation increased blood glucose, white blood cell (WBC), ruminal propionate and total volatile fatty acid levels. There is heterogeneity among the articles used in the study, and aspects of studied covariates explained the variation. In conclusion, this study indicated that dietary yeast can positively influence growth performance, haemato-biochemical indices, and rumen fermentation parameters of growing goats.

Analysis of serum antioxidant capacity and gut microbiota in calves at different growth stages in Tibet.

The hypoxic environment at high altitudes poses a major physiological challenge to animals, especially young animals, as it disturbs the redox state and induces intestinal dysbiosis. Information about its effects on Holstein calves is limited. Here, serum biochemical indices and next-generation sequencing were used to explore serum antioxidant capacity, fecal fermentation performance, and fecal microbiota in Holstein calves aged 1, 2, 3, 4, 5, and 6 months in Tibet. Serum antioxidant capacity changed with age, with the catalase and malondialdehyde levels significantly decreasing (p < 0.05), and superoxide dismutase levels significantly increasing (p < 0.05) with age. No significant differences (p > 0.05) in total volatile fatty acid levels were noted between the groups. In all groups, Firmicutes, Bacteroidetes, and Actinobacteria were the three most dominant phyla in the gut. Gut microbial alpha diversity significantly increased (p < 0.05) with age. Principal coordinate analysis plot based on Bray-Curtis dissimilarity revealed significant differences (p = 0.001) among the groups. Furthermore, the relative abundance of various genera changed dynamically with age, and the serum antioxidant capacity was associated with certain gut bacteria. The study provides novel insights for feeding Holstein calves in high-altitude regions.

Effects of waste milk feeding on rumen fermentation and bacterial community of pre-weaned and post-weaned dairy calves.

The objective of this study was to investigate the effect of waste milk with antibiotic residue on rumen fermentation and rumen bacterial composition of dairy calves during pre-weaned and post-weaned periods. A total of 24 Holstein male calves (43.4 ± 0.93 kg body weight, mean ± standard error) were allocated into four blocks based on birth date. Dairy calves were supplied 100% milk replacer (MR, n = 8), 50% milk replacer mixed with 50% waste milk (MM, n = 8), or 100% waste milk (WM, n = 8). Ruminal samples were collected at 49 and 63 days of age and then subjected to determinations of pH value, volatile fatty acids (VFA), ammonia nitrogen (NH3-N) and 16S rRNA gene amplicon sequencing. The results showed that feeding WM had no effect on the pH value, the concentrations of VFA (acetic acid, propionic acid, butyric acid, isovaleric acid, valeric acid), and NH3-N in dairy calves compared to feeding MR. However, from 49 to 63 days of age, the pH value (p < 0.001) was significantly increased, while the levels of total VFA (p = 0.004), acetic acid (p = 0.01), propionic acid (p = 0.003) and valeric acid (p < 0.001) were significantly decreased. For rumen microorganisms, there was no differences in bacterial diversity among the treatments. But the relative abundance of Veillonellaceae was significantly lower (p = 0.05) in the calves fed WM than that from MR group at 49 days of age; however, no difference was detected at 63 days of age. Feeding WM to calves tended to reduce family Veillonellaceae and genus Olsenella in the rumen at 49 days of age (p = 0.049). Analysis of temporal changes in rumen bacteria based on alpha-diversity and beta-diversity as well as the microbial relative abundances did not exhibit any difference. In addition, relative abundances of Clostridia_UCG-014, Prevotella, Syntrophococcus, Eubacterium_nodatum_group, Pseudoramibacter and Solobacterium were correlated with rumen pH value and the concentrations of TVFA, propionic acid, isovaleric acid, valeric acid and NH3-N. In conclusion, compare to MR, calves supplied with WM had little changes on the rumen pH value, NH3-N or VFAs contents. Additionally, limited effects could be found on rumen microbiota in the calves fed WM. However, further studies needed to explore if there exist any long-term effects of early-life rumen microbiota modulation on dairy cows.

Effect of trimmed asparagus by-products supplementation in broiler diets on performance, nutrients digestibility, gut ecology, and functional meat production.

Background and Aim:Trimmed asparagus by-products (TABP) is the resultant waste from asparagus possessing. TABP has fructans, such as inulins and fructooligosaccharide, which can be utilized as an alternative prebiotic. This study was conducted to examine the effect of TABP dietary supplementation on the productive performance, nutrient digestibility, gut microbiota, volatile fatty acid (VFA) content, small-intestine histology, and meat quality of broilers.Materials and Methods:A total of 320 1-day-old broiler chicks (Ross 308®) were raised under ambient temperature and assigned through a completely randomized design to one of four dietary treatments, with four replicates per treatment. The dietary treatments comprised corn-soybean basal diet supplemented with 0 (control), 10, 30, or 50 g/kg TABP. All birds were provided drinking water and feed ad libitum to meet the standard nutritional requirements of National Research Council for broiler chickens.Results:TABP supplementation to the broilers significantly increased the apparent ether extract, crude fiber, and gross energy digestibility (p<0.05). TABP supplementation significantly increased lactic bacteria and Enterococcus spp. numbers as well as acetic, propionic, butyric, and total VFA levels (p<0.01); on the other hand, it also significantly decreased Salmonella spp. and Escherichia coli contents in the cecum compared with the control group (p<0.01). Moreover, TABP supplementation increased villus height in the duodenum and jejunum (p<0.01), cryptal depth in the jejunum and ileum (p<0.01), and villus surface areas in the duodenum, jejunum, and ileum (p<0.01). Overall, 0-35 day TABP supplementation significantly increased the feed intake (p<0.01) and average daily gain of broilers (p<0.05), but not significantly affected the viability, productive index, and economic benefit return (p>0.05). The carcass characteristics, pH, color, and water holding capacity of the chicken meat between groups were not significantly different (p>0.05). All levels of TABP supplementation appeared to be a feasible means of producing broilers with the lower serum low-density lipoprotein cholesterol and triglyceride levels as well as atherogenic indices of serum compared with the control (p<0.05). Cholesterol contents and palmitic acid, oleic acid, saturated fatty acids, and Monounsaturated fatty acids levels decreased with an increase of TABP supplementation (p<0.05). Furthermore, TABP supplementation decreased atherogenic index (AI) and thrombogenicity index (TI) of meat (p<0.05).Conclusion:Supplementation of 30 g/kg TABP in broiler diet could enhance broiler performance and provide chicken meat with beneficial properties, with decreased AI and TI resulted from altered cholesterol and fatty acid profiles.

Effects of oregano essential oil and capsicum extract on fattening, serum constituents, and rumen fermentation of lambs

This study investigated dietary supplementation of weaned lambs with Origanum vulgare essential oil and Capsicum oleoresin (chilli pepper) extract. Thirty-six eight-week-old male and female Menemen lambs were used in this study. Three dietary treatment groups consisted of T1, an unsupplemented control group; T2, a group supplemented with 300 mg/kg oregano essential oil, and T3, a group supplemented with 300 mg/kg Capsicum oleoresin. Feed and fresh water were available to the lambs ad libitum during the 56-day experiment. No significant effects of treatment were detected on growth rate, feed intake and feed conversion. In addition, serum urea, creatine, total protein, albumin, amylase, aspartate amino transferase (AST), alanine amino transferase (ALT), and gamma glutamyl transferase (GGT) levels did not differ among treatments on day 56 of the study. When oregano oil and capsicum extract were added to the feed, total volatile fatty acids (TVFA), acetate (AA), propionate (PA), butyrate (BA), isobutyrate (IBA), valerate (VA), and AA to PA ratio in the rumen were decreased significantly in comparison with the control group at two hours after feeding, with the effect of T2 being greater than that of T3. Female lambs had lower levels of TVFA than male lambs. Thus, although neither additive affected fattening performance and serum constituents of the lambs, both altered the rumen fatty acid profile.

The Substitution of Corn Silage with Potato Pulp Silage at Differing Level in Dairy Cows on Milk Yield, Composition and Rumen Volatile Fatty Acids*

The aim of this study was to determine the quality of potato pulp silage (PPS) prepared with wheat bran and barley straw and the effects of the substituting corn silage with potato pulp silage at differing levels in dairy cows on milk yield, composition and rumen volatile fatty acid (VFA). The study consisted of two experiments. Nutrient con-tents, fermentation parameters, in situ organic matter (OM) and starch degradabilities, in vitro digestibility (IVD) and metabolic energy (ME) content of PPS were determined in the first experiment. The effects of substituting corn silage with potato pulp silage at 0%, 15%, 30% and 45% in the diet of lactating 12 dairy cows on feed intake, milk yield, milk components, rumen fermentation parameters were evaluated in the second experiment. While dry matter (DM), OM and crude protein (CP) contents, pH of silages were statistically similar, starch content, in vitro organic matter digesti-bility (IVOMD), ME, net energy lactation (NEL), and lactic acid values were significantly higher in PPS compared with corn silage (P&amp;lt;0.05). Organic matter intake, milk yield, the composition of milk, post-feeding pH and total VFA levels of ruminal fluid at all sampling hours were similar among the dairy cows (P&amp;gt;0.05). It was concluded that; PPS prepared with wheat bran and straw had a very good silage quality and were even better than corn silage (control). Substitution of corn silage with PPS up to 45% did not cause any negative effects on rumen fermentation parameters and can be safely substituted with corn silage up to 45% in dairy cow diets.

Effects of rumen-degradable-to-undegradable protein ratio in ruminant diet on in vitro digestibility, rumen fermentation, and microbial protein synthesis.

Background and Aim:Feeding ruminants must notice the degradability of feed, especially protein. Microbial rumen requires ammonia from rumen degradable protein (RDP) beside that ruminant require bypass protein or rumen undegradable protein (RUP) and microbial crude protein. The aim of the study was to discover the best RDP:RUP ratio in beef cattle diets commonly used by Indonesian farmers using an in vitro methodology.Materials and Methods:Samples of Pennisetum purpureum, Leucaena leucocephala, Indigofera zollingeriana, cassava, maize, palm kernel cake, rice bran, and tofu waste were formulated into dietary treatments (dry matter [DM] basis). All experiments were carried out using a 3×3×2 factorial, randomized block design with three replications. Treatments consisted of three protein levels (12%, 14%, and 16%), two energy levels (65% and 70%), and three RDP:RUP ratio levels (55:45, 60:40, and 65:35). The experimental diets were incubated in vitro using buffered rumen fluid for 48 h at 39°C. After incubation, the supernatants were analyzed to determine pH, ammonia concentration, total volatile fatty acid (VFA), and microbial protein synthesis. The residues were analyzed to determine DM, organic matter, protein, and RUP digestibility.Results:Increased protein, energy, and RDP levels increased digestibility, ammonia concentrations, total VFAs, and microbial protein synthesis (p<0.05), while rations with 16% protein lowered these parameters (p<0.05).Conclusion:Increased dietary protein (from 12% to 14% DM), energy (from 65% to 70% DM), and RDP (from 55% to 65% crude protein [CP]) levels increased nutrient digestibility, ammonia concentration, total VFA levels, and microbial protein synthesis. The diet containing 14% DM dietary protein and 70% DM energy, which contained 55%, 60%, or 65% CP RDP optimally increased nutrient digestibility, ammonia concentration, total VFA levels, and microbial protein synthesis. Thus, feed based on these RDP:RUP ratios can optimize ruminant productivity.

Effects of wilting and additives on the ensiling quality and in vitro rumen fermentation characteristics of sudangrass silage.

ObjectiveThis study was conducted to investigate the effects of molasses and Lactobacillus plantarum on the ensiling quality and in vitro rumen fermentation of sudangrass silage prepared with or without wilting.MethodsThe ensiling experiment, measured with 3 replicates, was carried out according to a 2×4 (wilted stages×additives) factorial treatment structure. Dry matter of the fresh (210 g/kg fresh matter) or wilted (305 g/kg fresh matter) sudangrass were ensiled (packed into 5.0-L plastic jars) without additive (control) or with molasses (M), Lactobacillus plantarum (LP), or molasses + Lactobacillus plantarum (M+LP). After 60 days of ensiling, the silages were analyzed for the chemical, fermentation, and in vitro characteristics.ResultsAfter 60 days of ensiling, the fermentation parameters were affected by wilted, the additives and the interactions of wilted with the additives (p<0.05). The M+LP treatment at wilted had higher lactic acid levels and V-score (p<0.05) but lower pH values and butyric acid concentrations than the other treatments. In comparison with sudangrass before ensiling, after ensiling had lower dry matter and higher non-fibrous carbohydrate. The in vitro gas production, in vitro dry matter digestibility, in vitro crude protein digestibility, and in vitro acid fiber detergent digestibility changed under the effects of the additives. Significant interactions were observed between wilted and the additives in terms of in vitro gas production at 48 h, asymptotic gas production, gas production rate, half time, and the average gas production rate. The total volatile fatty acid levels in the additive treatments were higher than those in the control.ConclusionWilting and supplementation with molasses and Lactobacillus plantarum had the ability to improve the ensiling quality and in vitro nutrient digestibility of sudangrass silage. The M+LP treatment at wilted exhibited the strongest positive effects on silage quality and in vitro ruminal fermentation characteristics.

Effects of rumen-protected folic acid addition in maternal and post-weaning diets on growth performance, total tract digestibility, ruminal fermentation and blood metabolites in lambs

This study was performed to investigate the influence of maternal and post-weaning rumen-protected folic acid (RPFA) addition on growth performance, total tract digestibility, rumen fermentation parameters and blood metabolites of lambs. Sixty-six Hu lambs (50 ± 4.3 days of age and 16.4 ± 3.84 kg of body weight [BW], mean ± SD) from 120 Hu ewes (24 ± 4.2 months of age and 44.6 ± 5.43 kg of BW) were selected based on litter size, sex, BW and maternal diets and then assigned to six groups using a randomized block experimental design in a 3 × 2 factorial arrangement. The first factor was supplementary level of RPFA in the maternal diets and the different treatments included 0 mg (M0F), 16 mg (M16 F) and 32 mg (M32 F) FA per kg dry matter (DM). The second factor was the RPFA addition level in the offspring diets with 0 mg [OC] and 4.0 mg [OF] FA per kg DM. Lambs were fed a total mixed ration with a roughage-to-concentrate ratio of 50:50 on a DM basis. Average daily gain (ADG) of pre-weaning lambs showed a quadratic increase in response to RPFA added in the maternal diets. After weaning, dry matter intake was not affected by treatments. The ADG increased and the feed conversion ratio (FCR) decreased by lamb RPFA addition. Total tract digestibility of DM, organic matter and crude protein was higher for OF than for OC, and total tract digestibility of ether extract and neutral detergent fibre increased with maternal RPFA addition. The ruminal pH decreased, whereas total volatile fatty acid levels increased with maternal RPFA addition. The acetate to propionate ratio was elevated with maternal and/or lamb RPFA addition. Activities of amylase, trypsin, chymotrypsin and lipase in the intestinal chyme also increased with maternal RPFA addition. Concentrations of blood glucose, albumin, total protein, very low-density lipoprotein (VLDL), folate, growth hormone and insulin-like growth factor-1 (IGF-1) were greater for OF than for OC. Similarly, blood glucose, high density lipoprotein cholesterol, VLDL, folate and IGF-1 were elevated with maternal RPFA addition. These results indicate that addition of RPFA to the maternal and/or lamb diets promoted growth performance of the lambs by improving ruminal fermentation, intestinal enzymes activity, total tract digestibility and hormone secretion.

Effects of Tea Saponin Supplementation on Nutrient Digestibility, Methanogenesis, and Ruminal Microbial Flora in Dorper Crossbred Ewe.

Simple SummaryGreenhouse gas emissions are a serious cause of global warming and climate change, and have become a common focus for all countries. Methane has been proven the second most commonly occurring greenhouse gas. Ruminants have been blamed for substantially contributing to methane emissions. Supplementation with tea saponin (TS) effectively decreased methane emissions and nitrogen emissions. It is not only beneficial for environmental protection, but also has potential economic benefits.Two experiments were conducted using Dorper × thin-tailed Han crossbred ewes. In experiment 1, eighteen ewes were randomly assigned to two dietary treatments (a basal diet, or the same basal diet supplemented with 2.0 g tea saponin (TS)/head/day) to investigate the effects of TS supplementation on nutrient digestibility and methane emissions. In experiment 2, six ewes with ruminal cannulae were assigned to the same two dietary treatments as in experiment 1 to investigate the effects of TS supplementation on rumen fermentation and microbial flora. TS supplementation increased the apparent digestibility of organic matter (OM) (p = 0.001), nitrogen (N) (p = 0.036), neutral detergent fibre (NDF) (p = 0.001), and acid detergent fibre (ADF) (p < 0.001). Urinary N (p = 0.001) and fecal N (p = 0.036) output were reduced, and N retention (p = 0.001) and nitrogen retention/nitrogen intake (p = 0.001) were increased. Supplementary TS did not decrease absolute methane emissions (p = 0.519) but decreased methane emissions scaled to metabolic bodyweight by 8.80% (p = 0.006). Ammonia levels decreased (p < 0.001) and total volatile fatty acid levels increased (p = 0.018) in response to TS supplementation. The molar proportion of propionate increased (p = 0.007), whereas the acetate:propionate ratio decreased (p = 0.035). Supplementation with TS increased the population of Fibrobacter succinogenes (p = 0.019), but the population of protozoans tended to decrease (p = 0.054). Supplementation with TS effectively enhanced the apparent digestibility of OM, N, NDF, and ADF, and decreased methane emissions scaled to metabolic bodyweight.

In-vitro fermentation characteristics and methane reduction potential of mustard cake (Brassica juncea L.)

Aim:To assess the effect of mustard cake (Brassica juncea L.) levels in concentrate mixtures and in composite feed mixtures (CFMs) on in-vitro fermentation characteristics and methane production.Materials and Methods:Five concentrate mixtures were prepared with containing 30% oil cake, where linseed cake was replaced by mustard cake at the rate of 0%, 7.5%, 15.0%, 22.5%, and 30% in concentrate mixture. Mustard cake contained glucosinolate 72.58 µmol/g oil free dry matter (DM) and contents in diet were 0, 5.4, 10.9, 16.3, and 21.8 µmol/g of concentrate mixture, respectively. Concentrate mixture containing 15.0% mustard cake was found to produced minimum methane which was then used for the preparation of CFM containing 0%, 25%, 50%, and 75% levels with gram straw.Result:Increased levels of mustard cake in concentrate mixtures had a linear decrease (p<0.05) in the total gas production, and the 15% inclusion showed lowest methane concentration (quadratic, p<0.01). The degradability of DM and organic matter (OM) of concentrate mixtures did not change, however, pH and NH3-N concentrations of the fermentation medium showed linear (p<0.05) reductions with increased mustard cake levels. Increased levels of 15% mustard cake containing concentrate mixture in CFMs exhibited a trend (p=0.052) of increased gas production, whereas methane concentration in total gas, methane produced and degradability of DM and OM were also displayed a linear increase (p<0.05). However, the pH, NH3-N, and total volatile fatty acid levels decreased linearly (p<0.05) with increased levels of concentrate in CFMs.Conclusion:Reduction in methane production was evidenced with the inclusion of mustard cake in concentrate mixture at 15% level, and the CFMs with 25% concentrate, which contained 15% mustard cake, exhibited an improved fermentation and reduced methane production.

Community dynamics and significance of anaerobic protozoa during biomethanation of lignocellulosic waste

The diversity and community dynamics of anaerobic protozoa and their functional role during anaerobic digestion of a typical lignocellulose biomass in a lab scale leach bed coupled UASB reactor is reported in this study. The functional role played by different protozoa during various stages of methanogenesis was analyzed through linear regression analysis of individual protozoon counts with major hydrolytic enzyme activities, volatile fatty acid levels and biogas production. The protozoa community in the digester was represented by ciliates (Metopus, Cyclidium and Colpoda) and flagellates (Rhyncomonas, Menoidium and Bodo). Regression analysis revealed the relationship between total protozoa counts with the activity of cellulase (R2 = 0.71) pectinase (R2 = 0.50) amylase (R2 = 0.53) and xylanase (R2 = 0.34), total volatile fatty acid levels (R2 = 0.86) and biogas production (R2 = 0.78) in the digester. Moreover, it was found that both volatile fatty acid and biogas production is correlated with ciliate and flagellate populations. This study underlines the importance of both ciliates and flagellates in the anaerobic digestion process and, more specifically, the contribution by individual protozoa on hydrolysis, which is the rate limiting stage in anaerobic digestion.

A Study of Two-Stage Anaerobic Digestion of Solid Potato Waste using Reactors under Mesophilic and Thermophilic Conditions

A two-stage anaerobic digestion process operated under mesophilic and thermophilic conditions was investigated for the treatment of solid potato waste to determine optimal methane yield, efficiency of operation and process stability. A solid-bed reactor was used for hydrolysis/acidification stage while an upflow anaerobic sludge blanket (UASB) reactor was used in the second stage, for methanogenesis. Three sets of conditions were investigated: (I) mesophilic + mesophilic, (II) mesophilic + thermophilic and (III) thermophilic + thermophilic in the hydrolysis/acidification and methanogenesis reactors, respectively. The methane yield was higher under mesophilic conditions (0.49 1 CH4 g COD−1 degraded) than thermophilic conditions (0.41 1 CH4 g COD−1 degraded) with reference to the methanogenic reactors. (COD) - chemical oxygen demand. However, the digestion period was shorter in systems II and III than in system I. Also, in system III the UASB reactor (thermophilic conditions) could handle a higher organic loading rate (OLR) (36 g COD 1−1d−1) than in system I (11 g COD 1−1d−1) (mesophilic conditions) with stable operation. Higher OLRs in the methanogenic reactors resulted in reactor failure due to increasing total volatile fatty acid levels. In all systems, the concentration of propionate was one of the highest, higher than acetic acid, among the volatile fatty acids in the effluent. The results show the feasibility of using a two-stage system to treat solid potato waste under both mesophilic and thermophilic conditions. If the aim is to treat solid potato waste completely within a short period of time thermophilic conditions are to be preferred, but to obtain higher methane yield mesophilic conditions are preferable and therefore there is a need to balance methane yield and complete digestion period when dealing with large quantities of solid potato waste.

Feed intake, digestion kinetics and rumen volatile fatty acids in Menz rams supplemented with Lablab purpureus or graded levels of Leucaena pallida 14203 and Sesbania sesban 1198

35 Menz rams weighing 19.3 ± 0.87 kg (mean ± S.D.) were used in a randomized block design experiment that was conducted for 35 days at Debre Zeit Research Station of the International Livestock Research Institute, Ethiopia. The objectives of the study were to determine feed intake, apparent digestibility, passage rate and level of rumen volatile fatty acids (VFA) in Menz rams fed tef ( Eragrostis tef) straw. The basal diet was supplemented daily on DM basis with dried foliage of Lablab purpureus, LAB – (230 g) or graded levels of Leucaena pallida 14203, namely, LP1 – (170 g), LP2 – (230 g), LP3 – (290 g), and Sesbania sesban 1198, namely, SS1 – (170 g), SS2 – (230 g), and SS3 – (290 g). The nitrogen (N) content of the supplement feeds was over 28.8 g kg −1 DM, whereas it was only 8.5 g kg −1 DM in the basal feed. High contents of NDF (747.6 g kg −1 DM) and ADF (419.5 g kg −1 DM) were determined in tef straw compared to the supplement feeds. Among the supplement feeds, L. purpureus had relatively high NDF (454 g kg −1 DM) and ADF (346.2 g kg −1 DM) content. L. pallida 14203 contained relatively high levels of the anti-nutritive factors, namely, condensed tannins (82.7 Abs g −1 NDF) and soluble phenolics (27.9 g kg −1 DM). Basal feed DM intake ( P < 0.05) reduced with an increase in the level of L. pallida 14203 supplementation. The apparent digestibility of N, ADF and ADL was lower ( P < 0.001) in L. pallida 14203 than in L. purpureus or S. sesban 1198 supplemented rams. L. pallida 14203 promoted lower ( P < 0.05) fractional outflow rate of particulate matter from the rumen and longer rumen mean retention time than L. purpureus and S. sesban 1198. Higher levels of total VFA ( P < 0.001) were observed in S. sesban 1198 than in L. pallida 14203 supplemented rams. It was concluded that the anti-nutritive factors in L. pallida 14203 have a major impact on fractional outflow rate of particulate matter from the rumen, and the digestibility of nutrients, with particular limitations on N digestibility. Increasing levels of S. sesban 1198 supplementation reduced nutrient digestibility due to increased passage rate, and thus supplementation of animals with the lowest level of the fodder tree appears to be more appropriate. The relatively high fiber content of L. purpureus reduced intake and apparent digestibility of feed on a limited scale.

Effect of anaerobic fungi on in vitro feed digestion by mixed rumen microflora of buffalo

Five strains of anaerobic fungi isolated from the faeces of wild (hog deer, Cervus porcinus; blackbuck, Antelope cervicapra; spotted deer, Axis axis; nilgai, Baselophus tragocamelus) and rumen liquor of domestic (sheep, Ovies aries) ruminants showing high fibrolytic enzyme producing ability were added to mixed rumen microflora of buffalo to study their effect on the digestibility of lignocellulosic feed (wheat straw and wheat bran in the ratio of 80:20), enzyme production and fermentation end products in in vitro conditions. Among the 5 isolates studied, FNG5 (isolated from nilgai) showed the highest stimulating effect on apparent digestibility (35.31 +/- 1.61% vs. 28.61 +/- 1.55%; P < 0.05), true digestibility (43.64 +/- 1.73% vs. 35.37 +/- 1.65%; P < 0.01), neutral detergent fiber digestibility (29.30 +/- 2.58% vs. 18.47 +/- 2.12; P < 0.01) of feed 24 h after inoculation compared to the control group. The production of carboxymethyl cellulase, xylanase, acetyl esterase and beta-glucosidase was significantly (P < 0.05) higher in the FNG5 inoculated incubation medium. There was no improvement in the digestibility and enzyme production on the addition of the other 4 isolates. Total volatile fatty acid levels as well as the concentration of acetate, propionate, isobutyrate and valerate were significantly higher in the FNG5 added group as compared to the control group. The fungal isolate FNG5 from nilgai, a wild ruminant, was found to be superior to the other isolates tested and appears to have a potential to be used as a feed additive for improving fiber degradation in domestic ruminants.

Characteristics of Ruminal Fermentation of Wethers Fed Tofu Cake Silage with Ethanol

Tofu cake added with three levels of ethanol was made into silages and fed to four wethers to investigate characteristics of ruminal fermentation. The animals received a basal diet consisting of the second cut Orchardgrass hay and beet pulp (4:1) and either fresh tofu cake (control) or one of silages made of tofu cake added with ethanol at 2%, 4% and 6% levels was also fed so that it account for 20% of the whole ration. Feeding levels were determined based on metabolic body size and were restricted to 85% of voluntary intake levels. 1) The animals fed with tofu cake silages had different ruminal fermentation compared to those in the control. There were positive or negative linear effects of amount of ethanol added to tofu cake silage on ruminal pH, volatile fatty acid (VFA) and other parameters. 2) The higher the levels of ethanol added to tofu cake silage the higher the total VFA, acetic, valeric and caproic acid levels and adversely the lower the propionic acid levels. 3) The animals fed with tofu cake silages had significantly (P<0.01) higher ratios of propionic acid to acetic acid in the rumen fluid. 4) Rumen fluid taken from the animals fed with tofu cake silages had lower pH and lactic acid than that from the control. 5) Although there were no apparent increase in pH, total VFA level or any particular VFA levels in the rumen for the amount of tofu cake fed to the animals in this study, further investigations for optimum feeding levels of tofu cake are needed.

Effect of dietary fibre source on total tract digestibility, caecum volatile fatty acids and digestive transit time in the weaned piglet

Effects of the use of 200 g of either wheat bran, sugar beet pulp, soya bean hulls or alfalfa meal per kilogram diet on the digestive process of the weaned piglet were studied on 24 Duroc× Landrace male piglets, weaned at 28 days of age. Piglets had an initial mean live weight of 7.92(±1.1) kg and were randomly distributed in six successive blocks of four animals. The total tract apparent digestibility (TTAD) was 0.872, 0.887, 0.815 and 0.824 for energy and 0.847, 0.833, 0.665 and 0.795 for nitrogen for the wheat bran, sugar beet pulp, soya bean hulls and alfalfa meal diet, respectively ( P<0.01). The TTAD values for NDF were 0.615, 0.861, 0.721 and 0.593, and for ADF were 0.390, 0.779, 0.708 and 0.457 in diets based on wheat bran, sugar beet pulp, soya bean hulls and alfalfa meal, respectively ( P<0.01). The level of volatile fatty acids (VFAs) in the caecum contents changed from 3.80 to 4.96 mg g −1 when sugar beet pulp replaced soya bean hulls, respectively, the later producing a higher proportion of acetic acid ( P<0.05). The average molar proportions were 0.635, 0.245 and 0.10 for acetic, propionic and butyric acid, respectively. Soya bean hulls in the diet increased the level of total VFA by 15 or 30% when compared with the wheat bran or with the sugar beet pulp and the alfalfa meal, respectively ( P<0.05). For a constant nitrogen intake, the diet containing soya bean hulls supported the lowest nitrogen retention. The mean retention time was 51.5, 49.9, 56.9 and 37.7 h for diets based on wheat bran, sugar beet pulp, soya bean hulls and alfalfa meal, respectively ( P<0.01). In contrast to alfalfa meal, the soya bean hulls reduced the chromium excretion rate by 40% and delayed the inflexion point of the excretion curve by 11 h, and consequently the digestive transit time. In conclusion, sugar beet pulp has the highest degradation rate of NDF and ADF fractions. The inclusion of soya bean hulls leads to a decrease in the energy and nitrogen digestibility of the weaning diet. Finally, alfalfa meal was the most effective fibre source to regulate the digestive transit time.

Comparison of mesophilic and thermophilic upflow anaerobic sludge blanket reactors treating instant coffee production wastewater

Stable anaerobic digestion of settled instant coffee wastewater was achieved for over 100 days in mesophilic (35°C) and termophilic (55°C) UASB reactors. Thermophilic upflow anaerobic sludge blankets (UASBs) were seeded with mesophilic granules and converted to thermophilic operation by raising the temperature to 55°C in one step. Successful thermophilic operation was achieved within 28 days. Both mesophilic and thermophilic UASBs achieved stable digestion at organic loading rates (OLR) of up to 10 kg COD m −3 d −1 (hydraulic retention times (HRT) 24 h). Higher OLRs to the mesophilic resulted in reactor failure due to increasing total volatile fatty acid (TVFA) levels. The thermophilic UASB achieved stable operation at an OLR of 11.4 kg COD m −3 d −1 (21 h HRT) but an OLR of 13.3 kg COD m −3 d −1 (18 h HRT) saw a rise in TVFA from 80 to 600 mg l −1. COD reduction in the thermophilic UASB was slightly lower at all OLRs, achieving a 70% COD reduction compared to a 78% COD reduction in the mesophilic UASB. The average TVFA levels were low, but somewhat higher in the thermophilic UASB than the mesophilic UASB (100 mg l −1 compared to 25 mg l −1). It is concluded that either mesophilic or thermophilic digestion could be used successfully to treat settled instant coffee production wastewater in UASB reactors.