Fermentable Energy Research Articles

Slow-Release Urea for Dairy Cows: A Commercial Contemplation or a Futile Fantasy?

Modern dairy cows are dependent on viable protein sources to maintain adequately high and persistent milk production. However, qualified protein sources, such as soybean meal are usually high and not easily available. Feed-grade urea (FGU) has been utilized in dairy diets for decades to help economically. Some portions of dietary nitrogen are a point in this case. Nonetheless, FGU can be considered a potential source of microbial protein, only if adequate timely fermentable nitrogen sources are supplied to the rumen microbes for successful microbial protein synthesis. In addition, FGU has a rapid degradation rate in the rumen, which may cause microbial toxicity and excessive ammonia and urea production, leading to environmental issues. It means that the effective use of FGU would be challenging. Accordingly, by improving rumen synchrony and metabolism and cow performance such limitations can be overcome through the development of slow-release urea (SRU). However, compared with FGU recent studies do not fully support the practical and economic effectiveness of SRU, towards improved cow metabolism and performance. More experiments particularly with varying dietary fermentable energy sources are required to conclusively decide if SRU may be a practical contemplation towards increased dairy production sustainability or it is just an expensive useless fantasy.

Development of the thermophilic fungus Myceliophthora thermophila into glucoamylase hyperproduction system via the metabolic engineering using improved AsCas12a variants

BackgroundGlucoamylase is an important enzyme for starch saccharification in the food and biofuel industries and mainly produced from mesophilic fungi such as Aspergillus and Rhizopus species. Enzymes produced from thermophilic fungi can save the fermentation energy and reduce costs as compared to the fermentation system using mesophiles. Thermophilic fungus Myceliophthora thermophila is industrially deployed fungus to produce enzymes and biobased chemicals from biomass during optimal growth at 45 °C. This study aimed to construct the M. thermophila platform for glucoamylase hyper-production by broadening genomic targeting range of the AsCas12a variants, identifying key candidate genes and strain engineering.ResultsIn this study, to increase the genome targeting range, we upgraded the CRISPR-Cas12a-mediated technique by engineering two AsCas12a variants carrying the mutations S542R/K607R and S542R/K548V/N552R. Using the engineered AsCas12a variants, we deleted identified key factors involved in the glucoamylase expression and secretion in M. thermophila, including Mtstk-12, Mtap3m, Mtdsc-1 and Mtsah-2. Deletion of four targets led to more than 1.87- and 1.85-fold higher levels of secretion and glucoamylases activity compared to wild-type strain MtWT. Transcript level of the major amylolytic genes showed significantly increased in deletion mutants. The glucoamylase hyper-production strain MtGM12 was generated from our previously strain MtYM6 via genetically engineering these targets Mtstk-12, Mtap3m, Mtdsc-1 and Mtsah-2 and overexpressing Mtamy1 and Mtpga3. Total secreted protein and activities of amylolytic enzymes in the MtGM12 were about 35.6-fold and 51.9‒55.5-fold higher than in MtWT. Transcriptional profiling analyses revealed that the amylolytic gene expression levels were significantly up-regulated in the MtGM12 than in MtWT. More interestingly, the MtGM12 showed predominantly short and highly bulging hyphae with proliferation of rough ER and abundant mitochondria, secretion vesicles and vacuoles when culturing on starch.ConclusionsOur results showed that these AsCas12a variants worked well for gene deletions in M. thermophila. We successfully constructed the glucoamylase hyper-production strain of M. thermophila by the rational redesigning and engineering the transcriptional regulatory and secretion pathway. This targeted engineering strategy will be very helpful to improve industrial fungal strains and promote the morphology engineering for enhanced enzyme production.

242 The Impact of Feed Formulation and Feeding Methods on Pig and Poultry Production on the Environment

Abstract Dietary energy and nutrient losses associated with its conversion into animal products increase production costs and contribute to the environmental footprint of farms with the excessive application of nitrogen, phosphorus, or trace minerals from manure or carbon and methane losses. Formulating diets with the appropriate levels of minerals and amino acids can help improve dietary protein and energy efficiency and reduce nutrient losses. For example, an 8% reduction in dietary crude protein in pig feeds is estimated to increase nitrogen efficiency by more than 50%, while costing 11% less than a control diet without industrial amino acids. This reduction in protein intake also increases energy availability due to reduced energy losses associated with protein deamination. Urinary and intestinal fermentation energy losses can be 24% lower for pigs fed low-protein diets compared to control diets. Nonetheless, determining the optimal level of dietary amino acid remains a difficult challenge in conventional phase feeding systems. Therefore, group or individual precision feeding is another powerful tool to increase nutrient efficiency. By feeding individual growing-finishing pigs with diets tailored to their requirements, precision feeding can decrease nitrogen excretion by 30% and greenhouse gas emissions by 22% compared to conventional 3-phase feeding. The benefits of feeding pigs with low-protein diets and precision feeding techniques are additive and might result in a 61% protein efficiency of utilization. The formulation of very-low-protein diets and the implementation of precision feeding techniques rely on sound nutritional concepts and comprehensive biological models developed to precisely estimate individual real-time nutrient requirements and animal responses. Understanding the metabolic processes responsible for the observed variation between individual animals in their ability to utilize dietary nutrients is challenging, but there is a need to further improve nutrient efficiency and reduce the environmental impact of livestock production systems.

The Replacement of Ground Corn with Sugar Beet in the Diet of Pasture-Fed Lactating Dairy Cows and Its Effect on Productive Performance and Rumen Metabolism.

Simple SummaryCereal grains have increased in cost, and therefore dairy farmers try to find alternatives to provide energy in the rumen. Sugar beet roots have high energy content and may be a sound alternative to replace ground corn partially or totally in the diet of dairy cows. Thus, the aim of this study was to evaluate the replacement of ground corn with fresh sugar beet on the milk production responses, rumen metabolism, and profitability of pasture fed dairy cows. Although cows supplemented with sugar beet roots had reduced dry matter intake and milk production compared with control cows, fat percentage was increased, and therefore, there were no differences in energy corrected milk yield (FPCM) among the treatments. Moreover, feeding costs were reduced, and thus, the margin over feed costs was increased for sugar beets. In addition, the replacement of ground corn by sugar beets reduced urinary N excretion, and thus, it may contribute to the reduction in N2O emission from dairy systems. Using sugar beet roots as an energy supplement can be a suitable alternative to ground corn in pasture-fed lactating dairy cows, increasing the sustainability of dairy systems.(1) Background: Sugars have a potential to provide great amounts of fermentable energy in the rumen. Feeding fresh sugar beet (SB) to dairy cattle to replace a portion of the grain in the ration has not received sufficient attention. This study determined dry matter intake (DMI), feeding behavior, rumen fermentation and milk production responses when replacing corn grain with increasing levels of SB in pasture-fed lactating dairy cow diets. (2) Methods: A total of 12 early-lactation cows were used in a replicated (n = 4) 3 × 3 Latin square design. The control diet consisted of 21 kg dry matter (DM) composed of 6.3 kg DM green chopped perennial ryegrass, 7 kg DM grass silage, 2 kg DM of concentrate, 1 kg DM soybean meal and 4.5 kg DM of ground corn. The other treatments replaced 50% or 100% of the ground corn with SB roots. (3) Results: The replacement of ground corn with sugar beet reduced DMI and milk yield (p < 0.05), but it increased milk fat concentration (p = 0.045), reduced feeding costs and increased margin over feed costs (p < 0.01). Urinary nitrogen was linearly reduced with SB supplementation (p = 0.026). (4) Conclusions: Using SB roots as energetic supplement can be a suitable alternative to ground corn in pasture-fed lactating dairy cows.

Feeding Strategies to Reduce Nutrient Losses and Improve the Sustainability of Growing Pigs.

The efficiency of pig production using nutrients has increased over the years. Still, better efficiency of nutrient utilization can be achieved by feeding pigs with diets adjusted to their estimated requirements. An increase in nutrient efficiency of utilization represents economic gains while maximizing environmental performance. The objective of this paper is to review the impact of different methods of diet formulation that provide farm animals with the amount of nutrients to satisfy their needs while minimizing nutrient excretion and greenhouse gas emissions. Diet formulation is one tool that can help to maximize nitrogen and energy utilization by decreasing crude protein content in diets. The use of local feedstuff and non-human-edible products (e.g., canola meal) associated with synthetic amino acid inclusion in the diet are valuable techniques to reduce carbon footprint. Precision feeding and nutrition is another powerful tool that allows not only daily tailoring of diets for maximal nutrient efficiency of utilization but also to reduce costs and improve nitrogen efficiency of utilization. In this review, we simulated through mathematical models the nitrogen and energy efficiency of utilization resulting from crude protein reduction in the diet. An 8% crude protein reduction in the diet can increase nitrogen efficiency of utilization by 54% while costing 11% less than a control diet without synthetic amino acids. The same reduction in crude protein represented a major improvement in available energy due to the decrease of energetic losses linked to protein deamination. Urinary and hindgut fermentation energy losses were 24% lower for pigs fed with low-protein diets when compared to control diets. In terms of modern feeding techniques and strategies, precision feeding and nutrition can decrease nitrogen excretion by 30% when compared to group phase feeding. The benefits of feeding pigs with low-protein diets and precision feeding techniques are additive and might result in a 61% nitrogen efficiency of utilization. There is room for improvement in the way nutrient requirements are estimated in pigs. Improving the understanding of the variation of nutrient utilization among pigs can contribute to further environmental gains.

Increasing dietary proportion of wheat grain in finishing diets containing distillers' grains: impact on nitrogen utilization, ruminal pH, and digestive function.

Because of its high crude protein (CP) content, dietary inclusion of corn dried distillers' grains with solubles (DDGS) in finishing cattle diets can increase the ruminal loss of ammonia-nitrogen (NH3-N), which ends up excreted as urine urea-N (UUN). Increasing dietary fermentable energy supply can enhance ruminal use of N; however, it could also lead to acidotic conditions that compromise digestive function and animal performance. We evaluated the effects of partially replacing dietary corn grain with 20% or 40% (dry matter [DM] basis) wheat grain in finishing diets containing 15% corn DDGS on N utilization, ruminal pH, and digestive function. Nutrient intake and digestion, ruminal fermentation characteristics, microbial protein synthesis, route of N excretion, and blood metabolites were measured. Six ruminally fistulated crossbred beef heifers (initial body weight ± SD; 797 ± 58.8 kg) were used in a replicated 3 × 3 Latin square design with 28-d periods. Dietary treatments were either corn (73% of diet DM; CON), 53:20 corn:wheat blend (20W), or 33:40 corn:wheat blend (40W) as the major fermentable energy source. Dry matter intake (DMI) tended to be lower for heifers fed the 40W than CON and 20W diets. Feeding diets containing wheat grain led to an increase (P = 0.04) in neutral detergent fiber (NDF) intake. However, there was no diet effect (P ≥ 0.60) on apparent total tract DM and NDF digestibility. Feeding wheat grain led to a decrease (P ≤ 0.03) in mean and minimum pH, an increase (P = 0.04) in pH < 5.8 duration, and a tendency for an increase in the area and acidosis index for pH < 5.8 and 5.5. Nitrogen intake, which was lower (P = 0.04) for 40W than 20W heifers did not differ between CON and 20W heifers. There was no diet effect (P = 0.80) on ruminal NH3-N concentration and estimated microbial N flow. However, feeding diets containing wheat grain led to a decrease (P = 0.045) in UUN excretion (% total urine N). Fecal and total N excretion (% of N intake) increased (P < 0.01) following the addition of wheat grain to the diet. Apparent N retention was lower (P = 0.03) for 40W than CON and 20W heifers. In summary, although it led to a desirable decrease in UUN excretion, feeding wheat grain in corn DDGS-containing diets increased acidotic conditions in the rumen, which possibly led to the tendency for a decrease in DMI. The negative apparent N retention at the 40% wheat grain inclusion also suggests a decrease in nutrient supply, which could compromise feedlot performance.

Effects of Chlorella vulgaris, Nannochloropsis oceanica and Tetraselmis sp. supplementation levels on in vitro rumen fermentation

Microalgae constitute an underexploited feed resource for ruminant nutrition. The unique digestive tract of ruminants makes them best suited to utilise complex polysaccharides and non-protein nitrogen of eukaryotic microalgae, though contrasting effects on rumen fermentation have been reported. The current study aimed to assess the effects of microalgae species, inclusion level and basal substrates on in vitro rumen fermentation parameters. To this end, haylage and maize silage were supplemented with 2.5, 5 and 10% (w/w, dry matter basis) of Chlorella vulgaris, Nannochloropsis oceanica and Tetraselmis sp. and incubated for 24-h with rumen inocula non-adapted to microalgae. No significant interaction was observed among basal substrate, microalgae species and inclusion level for any of the parameters evaluated. Substrate and microalgae species interaction affected most fermentation parameters. The lowest gas and methane productions and yields, total volatile fatty acids (VFA) production and concentrations of acetic, butyric and most minor VFA observed when C. vulgaris was incubated with haylage suggest that rumen fermentation was inhibited to a greater extent by this microalgae, probably reflecting a low availability of rapidly fermentable carbohydrates due to differences in cell wall structure and composition. However, the opposite was observed when C. vulgaris was incubated with maize silage, suggesting an improvement in the synchrony between fermentable energy and degradable nitrogen. Microalgae species and inclusion level interaction mainly affected methanogenesis. The lowest methane yield with N. oceanica at 10% may be explained by its high content of polyunsaturated fatty acids. The interaction between basal substrate and microalgae inclusion level did not affect any parameter. Overall, the effects of the interactions between substrate and microalgae species and microalgae species and inclusion level, underpin the importance of identifying optimal microalgae species and inclusion levels according to the basal diet fed to ruminants.

Effect of sole maize and maize –lablab silage on the ruminal volatile fatty acids (VFAS) of grazing calves in the dry season

Silages of sole maize and mixtures of maize-lablab were made at harvest in plastic bags. The experimental Unit consists of twelve cross-bred yearling bulls (White Fulani x N’dama) calves weighing 71-72kg and were randomly allotted to three dietary treatments: Grazing + sole maize silage, Grazing + mixtures of maize-lablab silage and Unsupplemented grazing as control. The experimental design was a completely randomized design and lasted 84days. Silage diets were given between 07:30 and 11:00 hours daily before grazing. Rumen fluid was collected at the end of the study to evaluate the co-efficient of ruminal fluid. The crude protein content in sole maize silage was half of that in mixture of maize-lablab silage. Inclusion of lablab in maize stover silage increased the mineral content as well as the lignin fraction. The mean pH value of sole maize silage (3.80) was less (P &lt; 0.05) than 4.25 obtained with addition of lablab. The buffering capacity (5.37%) of sole maize silage significantly (P &lt; 0.05) increased to 5.71% in mixture of maize-lablab silage. Lactic acid contents differed was influenced significantly (P &lt; 0.05) with a mean value of 8.4% and 8.5% respectively in the sole maize silage and with lablab inclusion. Total volatile fatty acid (VFA) ranged from 56.7 μmoles/ml in calves without supplementation to 95.2 μmoles/ml in the calves fed mixture of maize-lablab silage. Mixture of Maize-lablab silage had the highest values for all the minerals determined in the feed materials while sole maize had the least. It was concluded from this trial, that forage legumes are relatively good sources of degradable nitrogen and fermentable energy, so their inclusion in the diet is likely to increase the rumen population of cellulolytic microbes and also proves that, mixture of maize-lablab silage could be used as supplement to enhance the growth and survival of calves during the dry season, when animal feeds are relatively scarce.

The effect of 2\u2032-fucosyllactose on simulated infant gut microbiome and metabolites; a pilot study in comparison to GOS and lactose

Human milk oligosaccharides (HMOs) shape gut microbiota during infancy by acting as fermentable energy source. Using a semi-continuous colon simulator, effect of an HMO, 2′-fucosyllactose (2′-FL), on composition of the infant microbiota and microbial metabolites was evaluated in comparison to galacto-oligosaccharide (GOS) and lactose and control without additional carbon source. Data was analysed according to faecal sample donor feeding type: breast-fed (BF) or formula-fed (FF), and to rate of 2′-FL fermentation: fast or slow. Variation was found between the simulations in the ability to utilise 2′-FL. The predominant phyla regulated by 2′-FL, GOS and lactose were significant increase in Firmicutes, numerical in Actinobacteria, and numerical decrease in Proteobacteria compared to control. Verrucomicrobia increased in FF accounted for Akkermansia, whereas in fast-fermenting simulations Actinobacteria increased with trend for higher Bifidobacterium, and Proteobacteria decrease accounted for Enterobacteriaceae. Short-chain fatty acids and lactic acid with 2′-FL were produced in intermediate levels being between ones generated by the control and GOS or lactose. In 2′-FL fast-fermenting group, acetic acid specifically increased with 2′-FL, whereas lactose and GOS also increased lactic acid. The results highlight specificity of 2′-FL as energy source for only certain microbes over GOS and lactose in the simulated gut model.

Effect of fortification of commercial glycerol and crude glycerol to straw based mixed substrate on fermentation kinetics and energy value

Effect of fortification of commercial glycerol and crude glycerol to straw based mixed substrate on fermentation kinetics and energy value

Effect of wet storage conditions on potato tuber transcriptome, phytohormones and growth

BackgroundStored potato (Solanum tuberosum L.) tubers are sensitive to wet conditions that can cause rotting in long-term storage. To study the effect of water on the tuber surface during storage, microarray analysis, RNA-Seq profiling, qRT-PCR and phytohormone measurements were performed to study gene expression and hormone content in wet tubers incubated at two temperatures: 4 °C and 15 °C. The growth of the plants was also observed in a greenhouse after the incubation of tubers in wet conditions.ResultsWet conditions induced a low-oxygen response, suggesting reduced oxygen availability in wet tubers at both temperatures when compared to that in the corresponding dry samples. Wet conditions induced genes coding for heat shock proteins, as well as proteins involved in fermentative energy production and defense against reactive oxygen species (ROS), which are transcripts that have been previously associated with low-oxygen stress in hypoxic or anoxic conditions. Wet treatment also induced senescence-related gene expression and genes involved in cell wall loosening, but downregulated genes encoding protease inhibitors and proteins involved in chloroplast functions and in the biosynthesis of secondary metabolites. Many genes involved in the production of phytohormones and signaling were also affected by wet conditions, suggesting altered regulation of growth by wet conditions. Hormone measurements after incubation showed increased salicylic acid (SA), abscisic acid (ABA) and auxin (IAA) concentrations as well as reduced production of jasmonate 12-oxo-phytodienoic acid (OPDA) in wet tubers. After incubation in wet conditions, the tubers produced fewer stems and more roots compared to controls incubated in dry conditions.ConclusionsIn wet conditions, tubers invest in ROS protection and defense against the abiotic stress caused by reduced oxygen due to excessive water. Changes in ABA, SA and IAA that are antagonistic to jasmonates affect growth and defenses, causing induction of root growth and rendering tubers susceptible to necrotrophic pathogens. Water on the tuber surface may function as a signal for growth, similar to germination of seeds.

Label-free quantitative proteomic analysis reveals the lifestyle of Lactobacillus hordei in the presence of Sacchromyces cerevisiae

Water kefir is a fermented beverage, which is traditionally prepared from sucrose, kefir grains, dried or fresh fruits, and water. L. hordei and S. cerevisiae are isolated as predominant and stable species of lactic acid bacteria and yeasts, respectively. In this study we demonstrate that label free quantitative proteomics is useful to study microbial interaction along the response of co-cultivated L. hordei TMW 1.1822 in the presence of S. cerevisiae TMW 3.221 as compared with their single cultures in a water kefir model. It is shown and L. hordei responds to S. cerevisiae in many respects revealing a mutualistic relationship. The data suggest that L. hordei responds to the presence of S. cerevisiae with adjustment of intracellular redox reactions controlled of proteins, which are part of Rex regulons and proteins involved in the glycolytic pathway and energy fermentation. An NADH, H+-driven metabolic switch to preferential production of butanediol instead of acetate or lactate, and up-regulation of arginine deiminase, alleviated acid stress and concomitantly protected S. cerevisiae against an acidic environment, which L. hordei generated in single culture. Moreover, the data suggest that the presence of S. cerevisiae in the nitrogen and fatty acids limited environment of the water kefir facilitated and improved the growth of L. hordei by delivering gluconate, fructose, amino acids, fatty acids or substrates for their biosynthesis. Up-regulation of the OppABCDF peptide transport and enzymes involved in amino acid metabolism indicates enhanced peptide uptake, as well as cross-feeding of L. hordei by glutamine, glutamate, histidine, tryptophan, methionine, proline, tryptophan delivered by S. cerevisiae.

Nitrogen recycling and feed efficiency of cattle fed protein-restricted diets

The ability of cattle to grow and reproduce when ingesting low-protein diets is a crucial attribute for productive beef cattle systems in the seasonally dry tropics and subtropics. Nitrogen (N) recycling to the rumen is an important and known physiological mechanism allowing ruminants to efficiently grow in low-protein diets, but is usually disregarded in the nutritional models. This review discusses the role and magnitude of N recycling to provide additional N as microbial substrate in the rumen and in determining the efficiency of ruminants ingesting low-protein diets, to better understand the major factors regulating N recycling to the rumen. In addition to a review of the literature, study-adjusted regressions were used to evaluate various aspects of crude protein (CP) intake and availability, N recycling and excretion. There is large variation in N excretion and N-use efficiency among diets and among individuals, illustrating the opportunity for improvement in overall efficiency of cattle production. These data indicated that N recycling to the entire gastrointestinal tract supplies from half to twice as much N available for microbial growth as does the diet. Addition of rumen-degradable protein can increase rumen efficiency in using the available energy, as, conversely, the addition of fermentable energy can increase rumen efficiency in using the available CP. The present review has demonstrated that both are possible because of greater N recycling. Also, the importance of preserving the available N for determining individual variation in feed efficiency and the implications for selection are discussed. Nitrogen recycling can be controlled at both the epithelial wall of compartments of the gastrointestinal tract and at the liver, where ureagenesis occurs. Addition of fermentable energy can increase N recycling to the rumen and to post-ruminal tract by acting at both sites, and the mechanisms for this are discussed in the text. Although the effect of altering CP concentration in the diet has been substantially investigated, other factors potentially modulating N recycling, such as total fermentable energy, sources of protein and energy, hormonal modulation, and genetic variance, remain poorly understood. The selection of more efficient animals and development of diets with a lower environmental impact inescapably means further elucidation of the N-recycling mechanism.

Aerococcus urinae and Globicatella sanguinis Persist in Polymicrobial Urethral Catheter Biofilms Examined in Longitudinal Profiles at the Proteomic Level.

Aerococcus urinae (Au) and Globicatella sanguinis (Gs) are gram-positive bacteria belonging to the family Aerococcaceae and colonize the human immunocompromised and catheterized urinary tract. We identified both pathogens in polymicrobial urethral catheter biofilms (CBs) with a combination of 16S rDNA sequencing, proteomic analyses, and microbial cultures. Longitudinal sampling of biofilms from serially replaced catheters revealed that each species persisted in the urinary tract of a patient in cohabitation with 1 or more gram-negative uropathogens. The Gs and Au proteomes revealed active glycolytic, heterolactic fermentation, and peptide catabolic energy metabolism pathways in an anaerobic milieu. A few phosphotransferase system (PTS)–based sugar uptake and oligopeptide ABC transport systems were highly expressed, indicating adaptations to the supply of nutrients in urine and from exfoliating squamous epithelial and urothelial cells. Differences in the Au vs Gs metabolisms pertained to citrate lyase and utilization and storage of glycogen (evident only in Gs proteomes) and to the enzyme Xfp that degrades d-xylulose-5′-phosphate and the biosynthetic pathways for 2 protein cofactors, pyridoxal 6′-phosphate and 4′-phosphopantothenate (expressed only in Au proteomes). A predicted ZnuA-like transition metal ion uptake system was identified for Gs while Au expressed 2 LPXTG-anchored surface proteins, one of which had a predicted pilin D adhesion motif. While these proteins may contribute to fitness and virulence in the human host, it cannot be ruled out that Au and Gs fill a niche in polymicrobial biofilms without being the direct cause of injury in urothelial tissues.

Field Assessment of Alfalfa Populations Recurrently Selected for Stem Cell Wall Digestibility

Genetic variability for stem cell wall (CW) digestibility could be exploited to improve rumen‐fermentable energy in alfalfa (Medicago sativa L.) forage. We evaluated in the field the response to recurrent selection for stem CW digestibility in alfalfa. Digestibility was assessed as the concentration of glucose released after enzymatic hydrolysis of fiber (enzyme‐released glucose, ERG). Two initial cultivars, 54V54 and Orca, and populations obtained after successive cycles of divergent selection for stem CW digestibility (D−1, D−2, D+1, and D+2) were established at three field sites in north, central, and south of Québec. Field trials conducted over two growing seasons showed that populations obtained after two selection cycles (D+2) had significantly higher CW digestibility (+20.7 mg ERG g−1 CW) than initial cultivars (average of 13% improvement of digestibility). The D+2 populations did not differ from the initial cultivars with regard to biomass yield, winter survival, and stem water soluble‐carbohydrate concentration. Increases of ERG concentrations were observed in response to each selection cycle, and broad‐sense heritability highlights a moderate control of genetic factors over environmental factors for CW digestibility. Recurrent selection for stem CW digestibility is a valuable approach to increase fermentable energy in alfalfa forage and improve N utilization by ruminants.

RUMINANT NUTRITION SYMPOSIUM: Effects of postruminal flows of protein and amino acids on small intestinal starch digestion in beef cattle.

Many nutritionists adopt feeding strategies designed to increase ruminal starch fermentation because ruminal capacity for starch degradation often exceeds amounts of starch able to be digested in the small intestine of cattle. However, increases in fermentable energy supply are positively correlated with increased instances of metabolic disorders and reductions in DMI, and energy derived by cattle subsequent to fermentation is less than that derived when glucose is intestinally absorbed. Small intestinal starch digestion (SISD) appears to be limited by α-glycohydrolase secretions and a precise understanding of digestion of carbohydrates in the small intestine remains equivocal. Interestingly, small intestinal α-glycohydrolase secretions are responsive to luminal appearance of milk-specific protein (i.e., casein) in the small intestine of cattle, and SISD is increased by greater postruminal flows of individual AA (i.e., Glu). Greater flows of casein and Glu appear to augment SISD, but by apparently different mechanisms. Greater small intestinal absorption of glucose has been associated with increased omental fat accretion even though SISD can increase NE from starch by more than 42% compared to ruminal starch degradation. Nonetheless, in vitro data suggest that greater glucogenicity of diets can allow for greater intramuscular fat accretion, and if greater small intestinal absorption of glucose does not mitigate hepatic gluconeogenesis then increases in SISD may provide opportunity to increase synthesis of intramuscular fat. If duodenal metabolizable AA flow can be altered to allow for improved SISD in cattle, then diet modification may allow for large improvements in feed efficiency and beef quality. Few data are available on direct effects of increases in SISD in response to greater casein or metabolizable Glu flow. An improved understanding of effects of increased SISD in response to greater postruminal flow of Glu and casein on improvements in NE and fates of luminally assimilated glucose could allow for increased efficiency of energy use from corn and improvements in conversion of corn grain to beef. New knowledge related to effects of greater postruminal flow of Glu and casein on starch utilization by cattle will allow nutritionists to more correctly match dietary nutrients to cattle requirements, thereby allowing large improvements in nutrient utilization and efficiency of gain among cattle fed starch-based diets.

Impact of rice gruel on rumen metabolites and growth performance of sheep.

Objectives:We investigated the impact of rice gruel as an alternative energy source of molasses as well as measured the effectiveness of rice gruel on the physiology of the rumen environment and the growth performance of growing lamb.Materials and methods:A number of 18 sheep with an average age of 7 months and mean body weight of 5.9 kg were selected and divided into three groups for 60 days long feeding trial with urea molasses straw (UMS), urea rice gruel straw (URS), and concentrate feed. Every fortnight interval, live weight was recorded and rumen liquor from every group was collected four times before and after feeding at 4-h interval to examine the rumen environment.Results:Color, odor, consistency, and protozoal motility remain unchanged in all three groups. The pH of the rumen liquor was highest at 8 h of post feeding among three groups. The bacterial count (6.1 × 1010) was higher in the group that consuming UMS than URS and concentrate feed. The rumen protozoa also showed a similar growth pattern in proportion to a number of rumen bacteria. At the end of the 60 days feeding trial, no significant differences (p ≤ 0.05) were found among the three groups in contrast to body weight gain. Conclusion:In the current feeding trial, the close similar effectiveness of rice gruel and molasses was found as a fermentable energy source. However, we suggest that rice gruel can be supplemented as a substitute for molasses under the situation when molasses are not available or expensive in field condition.

Fermentative energy conversion: Renewable carbon source to biofuels (ethanol) using Saccharomyces cerevisiae and downstream purification through solar driven membrane distillation and nanofiltration

Experimental studies on fermentative production of ethanol from renewable sugarcane juice as carbon source were carried out in a bench scale fermenter integrated with microfiltration, nanofiltration and membrane distillation units (MF-NF-MD) for downstream purification and concentration enrichment of ethanol. This new design is flexible, compact, eco-friendly, and modular and, operated in a cross flow module that ensures almost fouling-free membrane separation while overcoming the product inhibition of traditional batch fermenters. The system is blessed with steady and continuous ethanol production from sugarcane juice with comparatively high productivity 9.2gL−1h−1, yield 0.47gg−1 and concentration 54.3gL−1 using Saccharomyces cerevisiae (NCIM 3205) vis-à-vis the existing technologies. The new system enables continuous product withdrawal, separation and recycle of the biomass as well as residual carbon source back to the fermenter under high cell density without product inhibition. Membrane distillation in the final stage, increases product purity and results in significant concentration enrichment. The study culminates in development of a green and sustainable process for a biofuel production.

749 Effects of postruminal flows of protein and amino acids on small intestinal starch digestion in cattle

A large amount of cattle in the United States are fed starch-based diets because limitations to efficient production of meat and milk by cattle are frequently associated with limits in NE. Many nutritionists adopt feeding strategies designed to increase ruminal starch fermentation because ruminal capacity for starch degradation often exceeds amounts of starch able to be digested in the small intestine of cattle. However, increases in fermentable energy supply are positively correlated with increased instances of metabolic disorders and reductions in DMI, and energy derived by cattle subsequent to fermentation is less than that derived when glucose is intestinally absorbed. Apparently, small intestinal starch digestion (SISD) is limited by α-glycohydrolase secretions and a precise understanding of digestion of carbohydrates in the small intestine remains equivocal. Interestingly, small intestinal α-glycohydrolase secretions are responsive to luminal appearance of high-quality protein (i.e., casein) in the small intestine of cattle, and SISD is increased by greater postruminal flows of individual AA (i.e., Glu). Indeed, greater flows of casein and Glu appear to augment SISD but by apparently different mechanisms. Greater small intestinal absorption of glucose has been associated with increased omental fat accretion even though SISD can increase NE from starch by more than 42% compared to ruminal starch degradation. Nonetheless, in vitro data suggest that greater glucogenicity of diets can allow for greater intramuscular fat accretion, and if greater small intestinal absorption of glucose does not mitigate hepatic gluconeogenesis then increases in SISD may provide opportunity to increase synthesis of intramuscular fat. If duodenal metabolizable AA flow can be altered to allow for improved SISD in cattle, then diet modification may allow for large improvements in feed efficiency and beef quality. Few data are available on direct effects of increases in SISD in response to greater casein or metabolizable Glu flow. An improved understanding of effects of increased SISD in response to greater postruminal flow of Glu and casein on improvements in NE and fates of luminally assimilated glucose could allow for increased efficiency of energy use from corn and improvements in conversion of corn grain to beef. New knowledge related to effects of greater postruminal flow of Glu and casein on starch utilization by cattle will allow nutritionists to more correctly match dietary nutrients to cattle to allow large improvements in nutrient utilization and efficiency of gain among cattle fed starch-based diets.

Performance and nitrogen use efficiency in mid-lactation dairy cows fed timothy cut in the afternoon or morning

Shifting cutting from morning to afternoon has been shown to increase the concentration of nonstructural carbohydrates in forages. We hypothesized that, compared with a total mixed ration containing timothy baleage and silage cut in the morning (a.m.-cut TIM), a total mixed ration containing timothy baleage and silage cut in the afternoon (p.m.-cut TIM) would improve animal performance and N use efficiency in mid-lactation Holstein cows due to enhanced supply of ruminal fermentable energy. The objective of this study was to compare the effects of p.m.- versus a.m.-cut TIM on milk yield, concentrations and yields of milk components, ruminal metabolism, and plasma concentrations of AA in mid-lactation Holstein cows. Ten (6 ruminally cannulated) primiparous cows averaging 139±13 d in milk and 550±56 kg of body weight, and 6 (2 ruminally cannulated) multiparous cows averaging 128±11 d in milk and 632±57 kg of body weight at the beginning of the experiment, were used in a crossover design. Each period lasted 21 d with 14 d for diet adaptation and 7 d for data and sample collection. The concentration of nonstructural carbohydrates (water-soluble carbohydrates plus starch) was numerically greater in the p.m.- versus the a.m.-cut TIM and averaged 13.2±1.06% and 12.2±1.13%, respectively. Treatment × parity effects were observed for milk urea N, feed efficiency, and milk N efficiency, whereas parity effects were observed for nutrient intake, milk yield, and plasma concentration of several essential and nonessential AA. Intakes of dry matter (19.3 versus 18.6 kg/d) and nonstructural carbohydrates (2.56 versus 2.31 kg/d), and yields of 4% fat-corrected milk (23.1 versus 22.2 kg/d), energy-corrected milk (25.0 versus 24.1 kg/d), milk fat (0.91 versus 0.88 kg/d), and milk protein (0.77 versus 0.73 kg/d) were all greatest with feeding p.m.-cut TIM. Milk yield (23.5 versus 22.7 kg/d) tended to increase in cows fed p.m.-cut TIM. The ruminal fermentation profiles and plasma concentrations of AA were mostly unaffected by treatments. However, ruminal valerate (1.01 versus 1.17 mol/100 mol) and plasma Gly (172 versus 188 µM) were lowest with feeding p.m.-cut TIM. Overall, feeding mid-lactation dairy cows a total mixed ration that consisted of p.m.-cut timothy baleage and silage significantly increased dry matter intake and yields of milk, milk fat, and milk protein.