Symposium review: Technologies for improving fiber utilization

Effects of grass species and harvest date on cell wall components and feed efficiency of dairy cows

There is a balance between DM yield and feed value when choosing types of grasses on a farm depending on the acreages of farmland and types of ruminants to be fed. Therefore, optimisation of the harvest strategy for grass silage is important for profitable dairy farming. Tall fescue has high DM yield and can replace traditional grasses, such as timothy, in Northern Europe in a changing climate as it has been shown to be more drought tolerant. As differences in climate responses previously have been related to differences in cell wall structure between grass species and, consequently, in digestibility, it is highly relevant to compare these species at similar maturity stages and to investigate if a very early harvest date will diminish potential differences between the species. This study evaluated the effects of harvest date and forage species on the concentration of hydroxycinnamic acids in silages and its relationship to feed efficiency of dairy cows. Tall fescue and timothy were harvested at very early date on May 25 or at early date on May 31 in the spring growth cycle. Forty lactating dairy cows were used in a block design. Cows received 1 of 4 treatments: (1) tall fescue harvested at very early date, (2) timothy harvested at very early date, (3) tall fescue harvested at early date, and (4) timothy harvested at early date. Diets were formulated to have the same forage-to-concentrate ratio (49:51 on DM basis). Tall fescue silages showed greater concentrations of DM, ash, and CP than timothy silages. Grasses harvested at early date showed greater concentrations of NDF, ADL, and cell wall than grasses harvested at very early date. Tall fescue silages showed greater concentration of p-coumaric acid and lower in vitro organic matter digestibility (IVOMD) compared to timothy silages. Milk production and composition were not affected by treatments but cows fed tall fescue-based diets showed lower milk protein yield and greater milk urea nitrogen than when timothy-based diets were fed. Furthermore, cows receiving timothy-based diets showed greater feed efficiency compared to cows receiving tall fescue-based diets. Thus, the lower concentration of p-coumaric acid and the higher IVOMD was associated with greater feed efficiency of cows fed timothy-based diets compared to tall fescue-based diets.

Pearl millet a promising fodder crop for changing climate: a review

The agricultural sector faces colossal challenges amid environmental changes and a burgeoning human population. In this context, crops must adapt to evolving climatic conditions while meeting increasing production demands. The dairy industry is anticipated to hold the highest value in the agriculture sector in future. The rise in the livestock population is expected to result in an increased demand for fodder feed. Consequently, it is crucial to seek alternative options, as crops demand fewer resources and are resilient to climate change. Pearl millet offers an apposite key to these bottlenecks, as it is a promising climate resilience crop with significantly low energy, water and carbon footprints compared to other crops. Numerous studies have explored its potential as a fodder crop, revealing promising performance. Despite its capabilities, pearl millet has often been overlooked. To date, few efforts have been made to document molecular aspects of fodder-related traits. However, several QTLs and candidate genes related to forage quality have been identified in other fodder crops, which can be harnessed to enhance the forage quality of pearl millet. Lately, excellent genomic resources have been developed in pearl millet allowing deployment of cutting-edge genomics-assisted breeding for achieving a higher rate of genetic gains. This review would facilitate a deeper understanding of various aspects of fodder pearl millet in retrospect along with the future challenges and their solution. This knowledge may pave the way for designing efficient breeding strategies in pearl millet thereby supporting sustainable agriculture and livestock production in a changing world.

Effects of Sweet and Forge Sorghum Silages Compared to Maize Silage without Additional Grain Supplement on Lactation Performance and Digestibility of Lactating Dairy Cows

This study investigated the effects of replacing maize silage (MZS) with high-sugar sorghum silage (HSS) or forage sorghum silage (FSS) without additional grain supplement in the diets of dairy cows on nutrient digestibility, milk composition, nitrogen (N) use, and rumen fermentation. Twenty-four Chinese Holstein cows (545 ± 42.8 kg; 21.41 ± 0.62 kg milk yield; 150 ± 5.6 days in milk) were randomly assigned to three dietary treatments (n = 8 cows/treatment). The cows were fed ad libitum total mixed rations containing (dry matter basis) either 40% MZS (MZS-based diet), 40% HSS (HSS-based diet), or 40% FSS (FSS-based diet). The study lasted for 42 days, with 14 days devoted to adaptation, 21 days to daily feed intake and milk production, and 7 days to the sampling of feed, refusals, feces, urine, and rumen fluid. Milk production was measured twice daily, and digestibility was estimated using the method of acid-insoluble ash. The data were analyzed using a one-way ANOVA in SPSS 22.0 according to a completely randomized design. Dietary treatments were used as fixed effects and cows as random effects. The results indicate that MZS and HSS had greater crude protein but less neutral detergent fiber (NDF), acid detergent fiber (ADF), acid detergent lignin (ADL), and a lower pH than FSS (p ≤ 0.04). High starch contents in MZS and water-soluble carbohydrate (WSC) contents in HSS were observed (p < 0.01). While the highest starch intake was observed for the MZS-based diet, the highest WSC intake was noted for the HSS-based diet, and the highest NDF, ADF, ADL intake was observed for the FSS-based diet (p ≤ 0.05). The diets, including MZS and HSS, had greater digestibility than that of FSS (p ≤ 0.03). Feeding MZS- and HSS-based diets increased the yield, fat, and protein content of the milk, as well as feed conversion efficiency (p ≤ 0.03). However, feeding the MZS- and HSS-based diets decreased the contents of milk urea N, urinary urea N, and urinary N excretion more than the FSS-based diet (p ≤ 0.05). The N use efficiency tended to increase relative to diets containing MZS and HSS compared with FSS (p = 0.06 and p = 0.09). Ruminal ammonia-N and pH were lower, but total volatile fatty acids, acetate, and propionate were higher in cows fed the HSS- and MZS-based diets compared to those fed the FSS-based diet (p ≤ 0.03). It appears as though replacing MZS with HSS in the diet of cows without additional grain supplements has no negative influence on feed intake, milk yield, N utilization, or ruminal fermentation.

Degradation of edible mushroom waste by Hermetia illucens L. and consequent adaptation of its gut microbiota

The edible fungus industry is one of the pillar industries in the Yunnan-Guizhou Plateau, China. The expansion of the planting scale has led to the release of various mushroom residues, such as mushroom feet, and other wastes, which are not treated adequately, resulting in environmental pollution. This study investigated the ability of black soldier fly (Hermetia illucens L.) larvae (BSFL) to degrade mushroom waste. Moreover, this study analyzed changes in the intestinal bacterial community and gene expression of BSFL after feeding on mushroom waste. Under identical feeding conditions, the remaining amount of mushroom waste in Pleurotus ostreatus treatment group was reduced by 18.66%, whereas that in Flammulina velutipes treatment group was increased by 31.08%. Regarding gut microbial diversity, compared with wheat bran-treated control group, Dysgonomonas, Providencia, Enterococcus, Pseudochrobactrum, Actinomyces, Morganella, Ochrobactrum, Raoultella, and Ignatzschineria were the most abundant bacteria in the midgut of BSFL in F. velutipes treatment group. Furthermore, Dysgonomonas, Campylobacter, Providencia, Ignatzschineria, Actinomyces, Enterococcus, Morganella, Raoultella, and Pseudochrobactrum were the most abundant bacteria in the midgut of BSFL in P. ostreatus treatment group. Compared with wheat bran-treated control group, 501 upregulated and 285 downregulated genes were identified in F. velutipes treatment group, whereas 211 upregulated and 43 downregulated genes were identified in P. ostreatus treatment group. Using Kyoto Encyclopedia of Genes and Genomes and Gene Ontology enrichment analyses, we identified 14 differentially expressed genes (DEGs) related to amino sugar and nucleotide sugar metabolism in F. velutipes treatment group, followed by 12 DEGs related to protein digestion and absorption. Moreover, in P. ostreatus treatment group, two DEGs were detected for fructose and mannose metabolism, and two were noted for fatty acid metabolism. These results indicate that feeding on edible mushroom waste can alter the intestinal microbial community structure of BSFL; moreover, the larval intestine can generate a corresponding feedback. These changes contribute to the degradation of edible mushroom waste by BSFL and provide a reference for treating edible mushroom waste using BSFL.

Effect of cassava pulp treated with Lactobacillus casei TH14, urea, and molasses on gas kinetics, rumen fermentation, and degradability using the in vitro gas technique

This study focused on examining the gas dynamics, rumen fermentation, and digestibility of ensiled cassava pulp (CSVP) using Lactobacillus casei TH14, urea, and molasses in the context of a laboratory experiment. All data in this study were analyzed using treatments arranged in 2 × 2 × 2 factorial arrangements using a completely randomized design. The L.casei TH14 additive (L) was factor A. Factor B was the molasses additive (M), while factor C was urea (U). There was no interaction effect of L, U, and M on gas production, volatile fatty acid (VFA) content, pH value, or ammonia-nitrogen level (P<0.05). The interaction of L, U, and M influenced in vitro dry matter digestibility (IVDMD) at 12 h (P < 0.05), and the CSVP fermented with the additions of L, U, and M together (LUM) was higher than the additions of CON, M, U, UM, and L on IVDMD (P < 0.05). However, the IVDMD values of adding LUM were higher in the control group (CON), M, U, UM, and L additive groups (P < 0.05). There was an interaction effect of L, U, and M on the protozoal count at 8 h (P<0.05), which had a lower protozoal count in the control group. In addition, acetic acid and butyric acid concentrations at 4 h and 8 h (P<0.05) were increased during the fermentation of CSVP using L and M combinations. Furthermore, the combination of U and M enhanced (P<0.05) average acetic acid, propionic acid, and pH at 4 h and 8 h while reducing (P<0.05) the gas generation from the insoluble portion (b). It was suggested that utilizing L. casei TH14 together with urea and molasses can enhance nutrient contents and improve the in vitro dry matter digestibility of CSVP, although it has no effect on ruminal fermentation or gas production.

Supply of palmitic, stearic, and oleic acid changes rumen fiber digestibility and microbial composition

The concept that fat supplementation impairs total-tract fiber digestibility in ruminants has been widely accepted over the past decades. Nevertheless, the recent interest in the dietary fatty acid profile to dairy cows enlightened the possible beneficial effect of specific fatty acids (e.g., palmitic, stearic, and oleic acids) on total-tract fiber digestibility. Because palmitic, stearic, and oleic acids are the main fatty acids present in ruminal bacterial cells, we hypothesize that the dietary supply of these fatty acids will favor their incorporation into the bacterial cell membranes, which will support the growth and enrichment of fiber-digesting bacteria in the rumen. Our objective in this experiment was to investigate how dietary supply of palmitic, stearic, and oleic acid affect fiber digestion, bacterial membrane fatty acid profile, microbial growth, and composition of the rumen bacterial community. Diets were randomly assigned to 8 single-flow continuous culture fermenters arranged in a replicated 4 × 4 Latin square with four 11-d experimental periods. Treatments were (1) a control basal diet without supplemental fatty acids (CON); (2) the control diet plus palmitic acid (PA); (3) the control diet plus stearic acid (SA); and (4) the control diet plus oleic acid (OA). All fatty acid treatments were included in the diet at 1.5% of the diet (dry matter [DM] basis). The basal diet contained 50% orchardgrass hay and 50% concentrate (DM basis) and was supplied at a rate of 60 g of DM/d in 2 equal daily offers (0800 and 1600 h). Data were analyzed using a mixed model considering treatments as fixed effect and period and fermenter as random effects. Our results indicate that PA increased in vitro fiber digestibility by 6 percentage units compared with the CON, while SA had no effect and OA decreased fiber digestibility by 8 percentage units. Oleic acid decreased protein expression of the enzymes acetyl-CoA carboxylase compared with CON and PA, while fatty acid synthase was reduced by PA, SA, and OA. We observed that PA, but not SA or OA, altered the bacterial community composition by enhancing bacterial groups responsible for fiber digestion. Although the dietary fatty acids did not affect the total lipid content and the phospholipid fraction in the bacterial cell, PA increased the flow of anteiso C13:0 and anteiso C15:0 in the phospholipidic membrane compared to the other treatments. In addition, OA increased the flow of C18:1 cis-9 and decreased C18:2 cis-9,cis-12 in the bacterial phospholipidic membranes compared to the other treatments. Palmitic acid tended to increase bacterial growth compared to other treatments, whereas SA and OA did not affect bacterial growth compared with CON. To our knowledge, this is the first research providing evidence that palmitic acid supports ruminal fiber digestion through shifts in bacterial fatty acid metabolism that result in changes in growth and abundance of fiber-degrading bacteria in the microbial community.

An In Vitro Study on the Role of Cellulases and Xylanases of Bacillus subtilis in Dairy Cattle Nutrition

The administration of Bacilli to dairy cows exerts beneficial effects on dry matter intake, lactation performance, and milk composition, but the rationale behind their efficacy is still poorly understood. In this work, we sought to establish whether cellulases and xylanases, among the enzymes secreted by B. subtilis, are involved in the positive effect exerted by Bacilli on ruminal performance. We took advantage of two isogenic B. subtilis strains, only differing in the secretion levels of those two enzymes. A multi-factorial study was conducted in which eight feed ingredients were treated in vitro, using ruminal fluid from cannulated cows, with cultures of the two strains conveniently grown in a growth medium based on inexpensive waste. Feed degradability and gas production were assessed. Fiber degradability was 10% higher (p < 0.001) in feeds treated with the enzyme-overexpressing strain than in the untreated control, while the non-overexpressing strain provided a 5% increase. The benefit of the fibrolytic enzymes was maximal for maize silage, the most recalcitrant feed. Gas production also correlated with the amount of enzymes applied (p < 0.05). Our results revealed that B. subtilis cellulases and xylanases effectively contribute to improving forage quality, justifying the use of Bacilli as direct-fed microbials to increase animal productivity.

Nitrogen and energy utilization and methane emissions of sheep grazing on annual pasture vs. native pasture

The purpose of this study was to evaluate the differences in annual pasture and native pasture on dry matter (DM) intake, nutrient digestibility, nitrogen (N) and energy utilization, and methane (CH4) emission of grazing sheep, and to provide the basis for rational livestock grazing in salinized regions. The study used 10 male Hu sheep ♀ × thin-tailed Han sheep ♂ rams (20 ± 5 kg) aged 5 mo. Sheep grazing was conducted in annual pasture and native pasture using a 2 × 2 Latin square design. After a 15-d adaptation period for grazing, the digestion and metabolism experiment of sheep were conducted, while CH4 emissions were measured using sulfur hexafluoride tracer gas. DM intake did not differ between annual pasture and native pasture (P = 0.386). Meanwhile, the digestibility of DM (P < 0.001), neutral detergent fiber (P < 0.001), acid detergent fiber (P < 0.01), crude protein (P < 0.001), and ether extract (P < 0.001) of sheep grazing on native pasture was significantly higher than that of annual pasture. Sheep grazing on native pasture had increased N intake (P < 0.001) and N retained (P < 0.001) compared with those grazing on annual pasture. Digestion energy (P < 0.05) and metabolic energy (P < 0.01) of sheep grazing on annual pasture were significantly improved compared with those on native pasture, while fecal energy (P < 0.001), urine energy (P < 0.001) and CH4 energy (CH4-E) output (P < 0.001) and CH4 emission (P < 0.001) of sheep grazing on annual pasture were significantly decreased. The CH4-E/gross energy (GE) values of sheep grazing on annual pasture and native pasture were 0.09 and 0.10, respectively. In conclusion, grazing sheep have higher N utilization on native pasture, whereas grazing sheep have higher energy utilization and low CH4 emissions in annual pasture. In conclusion, annual pasture has a lower CH4-E/GE compared to native pasture, which helps in reducing environmental pollution.

New insights in improving sustainability in meat production: opportunities and challenges

Treating livestock as senseless production machines has led to rampant depletion of natural resources, enhanced greenhouse gas emissions, gross animal welfare violations, and other ethical issues. It has essentially instigated constant scrutiny of conventional meat production by various experts and scientists. Sustainably in the meat sector is a big challenge which requires a multifaced and holistic approach. Novel tools like digitalization of the farming system and livestock market, precision livestock farming, application of remote sensing and artificial intelligence to manage production and environmental impact/GHG emission, can help in attaining sustainability in this sector. Further, improving nutrient use efficiency and recycling in feed and animal production through integration with agroecology and industrial ecology, improving individual animal and herd health by ensuring proper biosecurity measures and selective breeding, and welfare by mitigating animal stress during production are also key elements in achieving sustainability in meat production. In addition, sustainability bears a direct relationship with various social dimensions of meat production efficiency such as non-market attributes, balance between demand and consumption, market and policy failures. The present review critically examines the various aspects that significantly impact the efficiency and sustainability of meat production.

Effects of the Incubation Period of Pleurotus ostreatus on the Chemical Composition and Nutrient Availability of Solid-State-Fermented Corn Stover

The current study aimed to optimize and improve the feeding value of Pleurotus ostreatus-fermented corn stover by evaluating the effects of five solid-state fermentation times and three in vitro fermentation periods on the chemical composition, dry matter disappearance (DMD), microbial mass and volatile fatty acid (VFA) production of treated and untreated corn stover. The study utilized a 3 × 5 factorial design, with eight replicates per treatment. Dry matter, crude protein (CP), ash and non-fiber carbohydrate (NFC) contents increased quadratically (p < 0.05) with increases in the solid-state fermentation time. Increases of 44.4-59.1%, 20.6-78.6% and 40.5-121% were noted for the CP, ash and NFC contents, respectively. Organic matter, ether extract, neutral detergent fiber and hemicellulose contents decreased quadratically (p < 0.05) across the treatments. Similar trends were noted for DM and fiber disappearance in the treatments. The total gas production and in vitro true dry matter digestibility (IVTDMD) increased quadratically, while microbial mass and in vitro apparent DMD increased in a linear manner. The total VFA, propionate and butyrate contents increased linearly. Both the acetate content and the A:P ratio decreased in a linear manner. The results show that the rumen fermentation pathway favors the production of propionate, with increases in propionate production of 7.46 and 8.30% after 2 and 4 wk, respectively. The study showed that a 2 wk period of solid-state fermentation is sufficient to provide a bio-transformed cow-calf feed resource from P. ostreatus-treated corn stover.

Production of 17 strains of edible mushroom grown on corn stover and its effect on the chemical composition and ruminal in vitro digestibility of the residual substrate

The objective of this study was to evaluate the production (P) (g of fresh mushrooms /bag) and biological efficiency (BE) (g of fresh mushrooms per 100 g of dry substrate) of 17 fungal strains, namely Pleurotus ostreatus Po-IAP, Po-P38, Po-P14, Po-IE202, Po-Sfco, Po-JP, Po-Psma, and Po-POS, Pleurotus djamour Pd-PRO and Pd-UTMR, Pleurotus eryngii Pe-MB and Pe-PQ, Lentinula edodes L15, L9, L5, and LC, and Hericium erinaceus Heri, produced in corn stover (CS) and to assess the content of crude protein (CP), lignin (L), cellulose, hemicellulose, acid detergent fiber (ADF), and neutral detergent fiber (NDF) and in vitro digestibility of dry matter (IVDMD) of the residual substrate of CS, the so called spent mushroom substrate (SMS), in comparison to the non-inoculated substrate (C). The variables were analyzed as a completely randomized block design using R 4.0.3 software. Means were compared using Tukey's procedure. The Pleurotus spp. strains, compared to Lentinula spp. and Hericium spp., presented better BE and P. In comparison to C, the SMS increased the CP content (p < 0.05) from 10.8% (Po-JP) to 70.3% (LC), while NDF decreased (p < 0.05) from 11.5% (Pd-Pro) to 33.5% (L15) and IVDMD increased (p < 0.05) from 16.2% (Heri) to 47.7% (Pd-UTMR). In conclusion, of the 17 strains evaluated, the 3 strains of Lentinula edodes (L5, L15, and L9), one strain of Pleurotus djamour (Pd-UTMR), and one strain of Pleurotus ostreatus (Po-IAP) generated a SMS that, due to its nutritional improvement and increase in IVDMD, could be used as feed for ruminants. Our results also showed that corn stover is a suitable substrate to produce Pleurotus spp. fruiting bodies, with strain Po-IAP as the best yielding.

Metatranscriptomic analysis of the gut microbiome of black soldier fly larvae reared on lignocellulose-rich fiber diets unveils key lignocellulolytic enzymes

Recently, interest in the black soldier fly larvae (BSFL) gut microbiome has received increased attention primarily due to their role in waste bioconversion. However, there is a lack of information on the positive effect on the activities of the gut microbiomes and enzymes (CAZyme families) acting on lignocellulose. In this study, BSFL were subjected to lignocellulose-rich diets: chicken feed (CF), chicken manure (CM), brewers' spent grain (BSG), and water hyacinth (WH). The mRNA libraries were prepared, and RNA-Sequencing was conducted using the PCR-cDNA approach through the MinION sequencing platform. Our results demonstrated that BSFL reared on BSG and WH had the highest abundance of Bacteroides and Dysgonomonas. The presence of GH51 and GH43_16 enzyme families in the gut of BSFL with both α-L-arabinofuranosidases and exo-alpha-L-arabinofuranosidase 2 were common in the BSFL reared on the highly lignocellulosic WH and BSG diets. Gene clusters that encode hemicellulolytic arabinofuranosidases in the CAZy family GH51 were also identified. These findings provide novel insight into the shift of gut microbiomes and the potential role of BSFL in the bioconversion of various highly lignocellulosic diets to fermentable sugars for subsequent value-added products (bioethanol). Further research on the role of these enzymes to improve existing technologies and their biotechnological applications is crucial.

Invited review: Rumen modifiers in today's dairy rations

Our aim was to review feed additives that have a potential ruminal mechanism of action when fed to dairy cattle. We discuss how additives can influence ruminal fermentation stoichiometry through electron transfer mechanisms, particularly the production and usage of dihydrogen. Lactate accumulation should be avoided, especially when acidogenic conditions suppress ruminal neutral detergent fiber digestibility or lead to subclinical acidosis. Yeast products and other probiotics are purported to influence lactate uptake, but growing evidence also supports that yeast products influence expression of gut epithelial genes promoting barrier function and resulting inflammatory responses by the host to various stresses. We also have summarized methane-suppressing additives for potential usage in dairy rations. We focused on those with potential to decrease methane production without decreasing fiber digestibility or milk production. We identified some mitigating factors that need to be addressed more fully in future research. Growth factors such as branched-chain volatile fatty acids also are part of crucial cross-feeding among groups of microbes, particularly to optimize fiber digestibility in the rumen. Our developments of mechanisms of action for various rumen-active modifiers should help nutrition advisors anticipate when a benefit in field conditions is more likely.

Effects of inoculating feruloyl esterase-producing Lactiplantibacillus plantarum A1 on ensiling characteristics, in vitro ruminal fermentation and microbiota of alfalfa silage

BACKGROUND

Ferulic acid esterase (FAE)-secreting Lactiplantibacillus plantarum A1 (Lp A1) is a promising silage inoculant due to the FAE's ability to alter the plant cell wall structure during ensiling, an action that is expected to improve forage digestibility. However, little is known regarding the impacts of Lp A1 on rumen microbiota. Our research assessed the influences of Lp A1 in comparison to a widely adopted commercial inoculant Lp MTD/1 on alfalfa's ensilage, in vitro rumen incubation and microbiota.

RESULTS

Samples of fresh and ensiled alfalfa treated with (either Lp A1 or Lp MTD/1) or without additives (as control; CON) and ensiled for 30, 60 and 90 d were used for fermentation quality, in vitro digestibility and batch culture study. Inoculants treated silage had lower (P < 0.001) pH, acetic acid concentration and dry matter (DM) loss, but higher (P = 0.001) lactic acid concentration than the CON during ensiling. Compared to the CON and Lp MTD/1, silage treated with Lp A1 had lower (P < 0.001) aNDF, ADF, ADL, hemicellulose, and cellulose contents and higher (P < 0.001) free ferulic acid concentration. Compared silage treated with Lp MTD/1, silage treated with Lp A1 had significantly (P < 0.01) improved ruminal gas production and digestibility, which were equivalent to those of fresh alfalfa. Real-time PCR analysis indicated that Lp A1 inoculation improved the relative abundances of rumen's total bacteria, fungi, Ruminococcus albus and Ruminococcus flavefaciens, while the relative abundance of methanogens was reduced by Lp MTD/1 compared with CON. Principal component analysis of rumen bacterial 16S rRNA gene amplicons showed a clear distinction between CON and inoculated treatments without noticeable distinction between Lp A1 and Lp MTD/1 treatments. Comparison analysis revealed differences in the relative abundance of some bacteria in different taxa between Lp A1 and Lp MTD/1 treatments. Silage treated with Lp A1 exhibited improved rumen fermentation characteristics due to the inoculant effects on the rumen microbial populations and bacterial community.

CONCLUSIONS

Our findings suggest that silage inoculation of the FAE-producing Lp A1 could be effective in improving silage quality and digestibility, and modulating the rumen fermentation to improve feed utilization.

Mixed oats and alfalfa improved the antioxidant activity of mutton and the performance of goats by affecting intestinal microbiota

Oat hay and alfalfa hay are important roughage resources in livestock production. However, the effect of the mixture of oat hay and alfalfa hay on the meat quality of Albas goats is unclear. This study aimed to investigate the effects of feeding different proportions of oat hay and alfalfa hay on the growth performance and meat quality of Albas goats. Therefore, 32 goats were fed for 70 days and randomly divided into four treatment groups on the principle of similar weight: whole oat group (OAT), oat alfalfa ratio 3:7 group (OA73), oat alfalfa ratio 7:3 group (OA37) and whole alfalfa group (Alfalfa), with eight goats in each group. Daily feed intake records, feces, feed samples, and rumen fluid collection were made throughout the trial. The goats were weighed on the last day of the trial, and four goats per group were randomly selected for slaughter. Cecum contents, meat samples, and hot carcass weight were collected, and data were recorded. Furthermore, the relationship between the rumen and cecal microbes on performance and meat quality was clarified by analyzing the rumen and hindgut microbiomes. The results showed that feeding alfalfa could significantly reduce the daily weight gain of fattening goats. Compared with the highest group (OA37), the daily weight gain decreased by 19.21%. Although there was no significant change in feed intake in the four treatments, the feed conversion rate of the alfalfa group significantly decreased by 30.24-36.47% compared to the other groups. However, with the increased alfalfa content, MDA decreased significantly, T-AOC was up-regulated, and the antioxidant activity of the fattened goat meat fed with the high alfalfa group was significantly higher than that of the low alfalfa group. Notably, the abundance of Bacteroidales_unclassified and Clostridium were strongly correlated with T-AOC and MDA. Therefore, increasing the proportion of alfalfa in the diet can affect the antioxidant activity of goat meat by improving the gut microbiota, while an oat-hay mixture can improve the growth performance of livestock.

Effects of substituting agro-industrial by-products for soybean meal on beef cattle feed utilization and rumen fermentation

The purpose of the present investigation was to detect the effect of replacement of soybean meal (SBM) with citric waste fermented yeast waste (CWYW) as an alternative protein source of portentous substances in a concentrate mixture diet of beef cattle on intake, digestibility, ruminal fermentation, plasma urea-nitrogen, energy partitioning, and nitrogen balance. Four Thai-native beef bulls (170 ± 10.0 kg of initial body weight) were randomly allocated to a 4 × 4 Latin square design. The dietary treatments were four levels of CWYW replacing SBM in a concentrated diet at ratios of 0, 33, 67, and 100%. SBM was added to the concentrate diet at a dose of 150 g/kg DM. All cattle were offered ad libitum rice straw and the concentrate diet at 5 g/kg of body weight. The study was composed of four periods, each lasting for 21 days. The findings demonstrated that there was no difference in total dry matter intake, nutritional intake, or digestibility between treatments (p > 0.05). When CWYW replaced SBM at 100% after 4 h of feeding, ruminal pH, ammonia nitrogen, plasma urea nitrogen, and bacterial population were highest (p < 0.05). Volatile fatty acids and energy partitioning were not different (p > 0.05) among dietary treatments. Urinary nitrogen excretion was greatest (p < 0.05) for cattle fed CWYW to replace SBM at 100% of the concentrate. However, nitrogen absorption and retention for Thai-native cattle were similar (p > 0.05) among treatments. In conclusion, CWYW may be utilized as a substitute for SBM as a source of protein in Thai-native beef cattle without having an adverse impact on feed utilization, rumen fermentation characteristics, or blood metabolites.

Probiotic effect of ferulic acid esterase-producing Lactobacillus plantarum inoculated alfalfa silage on digestion, antioxidant, and immunity status of lactating dairy goats

A feeding experiment was conducted to determine the effects of inoculating alfalfa silage with a ferulic acid esterase-producing inoculum on feed digestibility, rumen fermentation, antioxidant, and immunity status of lactating dairy goats. Twenty dairy goats were distributed into 2 experimental groups consisting of control diet (Lp MTD/1, including Lactobacillus plantarum MTD/1 inoculated silage) against diet containing silage treated with ferulic acid esterase-producing L. plantarum A1 (Lp A1). Alfalfa silage inoculated with a ferulic acid esterase-producing Lp A1 had better fermentation quality than the Lp MTD/1 inoculation. The application of Lp A1 improved silage antioxidant capacity as indicated by greater total antioxidant capacity (T-AOC), superoxide dismutase (SOD) and glutathion peroxidase (GSH-Px) activities in Lp A1 treated silage versus Lp MTD/1 treatment. Compared with Lp MTD/1 treated group, inoculation of silage with Lp A1 increased apparent total tract digestibility of dietary dry matter, organic matter and crude protein, and ruminal concentrations of total volatile fatty acids, acetate, propionate and isobutyrate as well. The results of current study also demonstrated improved antioxidant capacity and immune performance of dairy goats with Lp A1 inoculation. Feeding Lp A1-treated silage increased dairy goats' serum antioxidase activity, such as T-AOC, SOD, GSH-Px and catalase, and the serum concentration of immunoglobulin A, while decreased tumor necrosis factor α, interleukin (IL)-2 and IL-6. In addition, compared with Lp MTD/1, diet containing alfalfa silage inoculated with Lp A1 endowed dairy goats' milk with greater fat and protein contents, improved dairy goat milk quality without affecting feed efficiency.

Physicochemical characterisation of barley straw treated with sodium hydroxide or urea and its digestibility and in vitro fermentability in ruminants

The development of strategies to overcome the shortage of forage due to persistently low rainfall is becoming a central task for animal nutrition in research and practice. In this study, it was investigated how the treatment of straw with NaOH or feed urea in a practicable procedure for modern farms affects rumen fermentation (gas production and greenhouse gas concentration) as well as the digestibility of feed energy and nutrients. For this purpose, the treatments were tested individually and in different proportions in a total mixed ration (TMR) in ruminal batch cultures in vitro and in a digestibility trial with sheep. In order to explain the observed effects at the molecular level, descriptive data from ¹³C solid state nuclear magnetic resonance (NMR) and Fourier-transform infrared (FTIR) spectroscopy were obtained. NaOH treatment of straw increased crude ash (CA), non-fibrous carbohydrates, digestible energy (DE), and metabolizable energy (ME) concentration, whereas the proportion of neutral detergent fibre (aNDFom) and hemicellulose decreased. In urea treated straw, NH₃-N and crude protein increased, whereas acid detergent lignin (ADL), DE, and ME decreased. The physically effective fibre (peNDF₈) concentration increased in TMR containing 18% of NaOH or urea treated straw (p < 0.01). The application of straw treatments as pure substrates (not as part of a TMR) increased gas production and decelerated ruminal fermentation (p < 0.05). In vitro organic matter digestibility (IVOMD) of the straw (0.31) increased after NaOH (0.51; p < 0.05) and urea treatment (0.41; p > 0.05). As part of a TMR, straw treatments had no distinct effect on gas production or IVOMD. Concentrations of CH₄ and CO₂ were likewise not affected. Apparent total tract digestibility of aNDFom, acid detergent fibre (ADFom), hemicellulose, and cellulose increased in the TMR by approximately 10% points following NaOH treatment (p < 0.05). The inclusion of urea treated straw did not affect apparent digestibility. Calculated true digestibility of aNDFom was 0.68, 0.74, and 0.79, of ADFom 0.58, 0.57, and 0.65, and of ADL 0.02, 0.13, and 0.08 in TMR including untreated, NaOH treated, and urea treated straw, respectively. ¹³C NMR and FTIR analyses consistently revealed that the global structure and crystallinity of the carbohydrates (cellulose and hemicellulose) was not altered by treatment and the concentration of lignin was likewise not affected. Depolymerisation of lignin did not occur. However, NMR signals assigned to acetyl groups were significantly altered indicating that straw treatments disrupted linkages between hemicelluloses and lignin. Moreover, the acetates signal was affected. This signal can be assigned to linkages between ferulic acids and hemicelluloses (arabinoxylans). FTIR spectra of straw treatments mainly differed at a wavelength of 1730 cm^-1 and 1240 cm^-1. Disappearance of the 1730 cm^-1 peak suggests removal of hemicelluloses or lignin related compounds by treatment. The disappearance of the lignin peak at 1240 cm^-1 could be due to conjugated ketone (phenyl-carbonyl) removal or the removal of ferulic and p-coumaric acid acetyl groups. Both treatments are supposed to release fermentable cell wall components (hemicelluloses) from lignin-associated bonds and as a result, straw fibre can be better fermented in the rumen. This contributes to energy supply and increased fibre digestibility at least in the TMR that contained NaOH treated straw. The alkaline straw treatments probably induced a release of phenolics such as ferulic acid and p-coumaric acid, which can be metabolised in the gut and the liver and metabolites might be excreted with the urine. This could notably contribute to metabolic energy losses.

Multivariate analysis identifying the main factors associated with cow productivity and welfare in tropical smallholder dairy farms in Vietnam

This study aimed to rank potential drivers of cow productivity and welfare in tropical smallholder dairy farms (SDFs) in Vietnam. Forty-one variables were collected from 32 SDFs located in four geographically diverse dairy regions, with eight SDFs per region. Twelve variables, including milk yield (MILK), percentages of milk fat (mFA), protein (mPR), dry matter (mDM), energy-corrected milk yield (ECM), heart girth (HG), body weight (BW), ECM per 100 kg BW (ECMbw), body condition score (BCS), panting score (PS), inseminations per conception (tAI), and milk electrical resistance (mRE) of cows, were fitted as outcome variables in the models. Twenty-one other variables describing farm altitude, housing condition, and diet for the cows, cow genotypes, and cow physiological stage were fitted as explanatory variables. Increased farm altitude was associated with increases in ECM and mRE and with decreases in PS and tAI (P < 0.05). Increases in roof heights and percentage of shed side open were associated with increases in ECM, mFA, and mDM (P < 0.05). Increased dry matter intake and dietary densities of dry matter and fat were associated with increased MILK, ECM, and ECMbw and decreased tAI (P < 0.05). Increased dietary lignin density was associated with increased PS. Increased genetic proportion of Brown Swiss in the herd was associated with increased MILK, ECM, and ECMbw (P < 0.05). Thus, to improve cow productivity and welfare in Vietnamese SDFs, the following interventions were identified for testing in future cause-effect experiments: increasing floor area per cow, roof heights, shed sides open, dry matter intake, dietary fat density, and the genetic proportion of Brown Swiss and decreasing dietary lignin density.

Ferulic Acid Esterase Producing Lactobacillus johnsonii from Goat Feces as Corn Silage Inoculants

Ferulic acid esterase (FAE+)-producing lactobacilli are being studied as silage inoculants due to their potential of increasing forage fiber digestibility. In this work, three FAE+ Lactobacillus (L.) johnsonii strains were isolated from caprine feces and characterized according to their potential probiotic characteristics and as silage inoculants. Limosilactobacillus fermentum CRL1446, a human probiotic isolated from goat cheese, was also included in the experiments as a potential silage inoculant. FAE activity quantification, probiotic characterization, and growth in maize aqueous extract indicated that L. johnsonii ETC187 might have a better inoculant and probiotic aptitude. Nevertheless, results in whole-corn mini silos indicated that, although acid detergent fiber (ADF) was significantly reduced by this strain (3% compared with the uninoculated (UN) group), L. johnsonii ETC150 and CRL1446 not only induced similar ADF reduction but also reduced dry matter (DM) loss (by 7.3% and 6.5%, respectively) compared with the UN group. Additionally, CRL1446 increased in vitro DM degradability by 10%. All treatments reduced gas losses when compared with the UN group. The potential probiotic features of these strains, as well as their beneficial impact on corn fermentation shown in this study, encourage further studies as enhancers in animal production.

Effect of dietary peNDF levels on digestibility and rumen fermentation, and microbial community in growing goats

Physically effective neutral detergent fiber (peNDF) is a concept that accounts for the particle length of NDF in diets, sustaining the normal chewing behavior and rumen fermentation of ruminants. Specifically, peNDF>1.18 is the commonest one that is calculated from NDF and the percentage of feed dry matter left on the 1.18, 8.00, and 19.00 mm sieves. This study aimed to investigate the effects of different levels of peNDF>1.18 on the rumen microbiome and its correlation with nutrient digestibility and rumen fermentation in goats. A total of 30 Lezhi black goats were randomized and blocked to five dietary treatments (n = 6). All the diets were identical in composition but varied in hay lengths, leading to the different peNDF>1.18 content of the diets: 32.97, 29.93, 28.14, 26.48, and 24.75%. The results revealed that the nutrient digestibility increased when dietary peNDF>1.18 levels decreased from 32.97% to 28.14%, with the highest digestibility at 28.14% peNDF>1.18 treatment, after which nutrient digestibility decreased with the decreasing of dietary peNDF levels. Ruminal NH3-N concentrations in the 29.93% and 28.14% groups were higher than that in the 24.75% group (p < 0.05). Ruminal microbial protein concentration was the highest in the 32.97% group (p < 0.05). Daily CH4 production in the 32.97% and 24.75% peNDF>1.18 treatments was lower than that in the 26.48% group (p < 0.05) and no differences were observed among other groups. The relative abundance of rumen fungi at the phylum and genus levels and archaea at the species were affected by dietary peNDF>1.18 content. In conclusion, decreasing dietary peNDF>1.18 levels within a certain range can improve nutrient digestibility and change the rumen microbial community structure of goats. Dietary peNDF>1.18 level should be 28.14% (roughage length around 1 cm) among the five levels for 4 months Lezhi black goats with the purpose of optimal nutrient digestibility.

Effects of a combination of fibrolytic and amylolytic enzymes on ruminal enzyme activities, bacterial diversity, blood profile and milk production in dairy cows

We hypothesised that adding a combination of fibrolytic and amylolytic enzymes to the diet of early-lactation dairy cows would improve rumen enzyme activity and bacterial diversity, promote energy metabolism, and benefit milk production in cows. Twenty multiparous early-lactation (90 ± 5 d) Holstein cows with similar body conditions were randomly allocated to control (CON, n = 10) and experimental (EXP, n = 10) groups in a completely randomised single-factor design. The CON was fed only a basal total mixed ration diet, and the diet of the EXP was supplemented with a combination of fibrolytic and amylolytic enzymes at 70 g/cow/d (cellulase 3 500 CU/g, xylanase 2 000 XU/g, β-glucanase 17 500 GU/g, and amylase 37 000 AU/g). The experiment lasted 28 days, with 21 days for adaptation and 7 days for sampling. Enzyme addition increased the activity levels of α-amylase and xylanase, and the ammonia-N concentration (P < 0.05) tended to increase the activity of β-glucanase (P = 0.08) in rumen fluid. However, there was no significant difference in the rumen bacterial richness and diversity, phylum (richness > 0.1%) or genus (richness > 1%) composition between the CON and EXP groups (P > 0.05). A tendency of difference was found between CON and EXP (R = 0.22, P = 0.098) in principal component analysis. Ten genera showed different abundances across the CON and EXP groups (linear discriminant analysis effect size, linear discriminant analysis > 2). EXP increased the ratio of albumin to globulin and the concentrations of total cholesterol and low-density lipoprotein cholesterol (P < 0.05) and tended to increase triglycerides (P = 0.09) in blood. Milk yield, 3.5% fat-corrected milk yield and energy-corrected milk yield increased with enzyme supplementation (P < 0.05). The production levels of milk fat and lactose increased, but the percentage of solids, not fat and protein, decreased in EXP (P < 0.05). Although the DM intake was not affected, the feed efficiency tended to increase (P = 0.07) in EXP. In conclusion, dietary supplementation with a mixture of fibrolytic and amylolytic enzymes on multiparous early-lactation dairy cows increased α-amylase and xylanase activity levels in rumen fluid, enhanced milk performance and tended to improve the feed efficiency in cows.

The Effect of Different Lactic Acid Bacteria Inoculants on Silage Quality, Phenolic Acid Profiles, Bacterial Community and In Vitro Rumen Fermentation Characteristic of Whole Corn Silage

Corn silage is an important source of forage, but whether or not bacterial inoculants should be applied is somewhat controversial in ruminant feeding practice. In the present study, chopped whole corn plants treated with a single inoculant of Lactobacillus buchneri (LB), Lactobacillus plantarum (LP), Pediococcus pentosaceus (PP) served as either homofermentation (e.g., lactate only) or heterofermentation (e.g., lactate and acetate) controls and compared with those treated with either a mixture of the lactic acid bacteria (QA: 60% LP, 10%PP, 30% LB) or a mixture of the lactic acid bacteria (QB: 60% LP, 15% PP, 25% LB), to investigate their effects on the fermentation quality, ester-linked phenolic acids, and in vitro digestibility. After 60 day ensiling, the addition of QA exhibited the lowest pH (3.51) with greater lactic acid (LA) production. The ester-linked ferulic acid (FAest) and p-coumaric acid (pCAest) concentrations were significantly decreased during 60 days ensiling. And among all these groups, the LB and QA treated group showed a lower concentration of FAest and pCAest than other groups. After 60 days ensiling, Lactobacillus was the dominant genus in all LAB treated groups. Meanwhile, negative correlations of Bacillus, Bacteroides, Bifidobacterium, Blautia, Prevotella, Ruminococcus, and Roseburia with FAest content after 60 days ensiling occurred in the present study. Komagataeibacter was mainly found in LB and PP addition silages, and presented a significant negative effect with the level of acid detergent fiber (ADF). To explore whether the addition of LABs can improve digestibility of whole corn silage, an in vitro rumen fermentation was conducted using the 60 day ensiled whole corn silages as substrates. The QA addition group exhibited a greater 48 h and 96 h in vitro dry matter and ADF disappearance, greater 48 h gas production and less methane emissions. Even though there were the same neutral NDF levels in corn silages treated with LB and QA after 60 days ensiling, the QA treated silages with lower FAest and pCAest presented higher IVDMD after 96 h and 48 h in vitro fermentation. In brief, the addition of mixed inoculants of 60% LB,10% PP, 30% LB compared with the addition of whichever single HoLAB or HeLAB inoculants, facilitated the release of ester-linked phenolic acids (e.g., ferulic and p-coumaric acids) and remarkably, improved silage quality in terms of sharp pH decline and greater lactate production. Taken together with the improvement in rumen microbial fermentation, the results obtained in the present study provided concrete evidence for the role of mixed LAB application in corn silage preparation for ruminant feeding practices.

Feeding behavior of post-weaned crossbred steers supplemented in the dry season of the year

The objective of this study was to evaluate the feeding behavior of grazing steers supplemented in the dry season of the year. Thirty-two castrated crossbred (½ Holstein-Zebu) steers with an average initial weight of 378 ± 7.54 kg, aged 14 months, were distributed into four treatment groups in a completely randomized design with eight replicates. The animals were managed in an area covered with a pasture of Brachiaria brizantha cv. Marandu, in a rotational grazing system. The supplement was formulated so that the animals in the different treatment groups would ingest the same amount of crude protein (CP) daily. Thus, the treatments consisted of increasing levels of supplementation, based on the animals' body weight (BW), as the protein content of the supplement was reduced. The following treatments (dry matter basis) were tested: T2, supplement at 0.2% BW, with 50% CP; T4, supplement at 0.4% BW, with 25% CP; T6, supplement at 0.6% BW, with 16.67% CP; and T8, supplement at 0.8% BW, with 12.5% CP. Forage dry matter intake decreased linearly (P < 0.05), characterizing a substitution effect. The increasing supplementation levels influenced the animals' feeding behavior, especially grazing time, total feeding time, number of grazing bouts, and number of bites per day, which showed a positive quadratic response (P < 0.05), and rumination time, number of rumination bouts, number of cuds ruminated per day, and number of chews per ruminated cud, which exhibited a negative quadratic behavior (P < 0.05). Dry matter and neutral detergent fiber (NDF) feed efficiencies and dry matter and NDF rumination efficiencies responded quadratically (P < 0.05). In conclusion, concentrate supplementation at up to 0.8% BW improves the feeding behavior of grazing steers in terms of the intake of concentrate supplement and forage as well as the feed and rumination efficiencies.

Effects of season, variety type, and trait on dry matter yield, nutrient composition, and predicted intake and milk yield of whole-plant sorghum forage

Sorghum forage is an important alternative to high-quality forage in regions where climatic and soil conditions are less desirable for corn production for silage and producing comparable nutritive value is challenging. The objective of this experiment was to assess the effects of season (spring vs. summer), sorghum variety type (forage sorghum vs. sorghum-sudangrass), and trait [brown midrib (BMR) vs. non-BMR] on dry matter (DM) yield, nutrient composition, and predicted intake and milk yield of whole-plant sorghum forage grown in Florida from 2008 to 2019. Whole-plant sorghum forage was harvested at a targeted 32% of DM, and each year, spring (April) and summer (July) trials were established. A total of 300 forage sorghum and 137 sorghum-sudangrass hybrids were tested for a total of 437 hybrids, of which 199 hybrids contained the BMR trait and 238 were non-BMR. An interaction between season and sorghum variety type was observed for DM yield. Dry matter yield was greater for the spring season than the summer season, with sorghum-sudangrass outperforming forage sorghum only during the spring season. In addition, BMR hybrids had a lower DM yield than non-BMR hybrids, regardless of season and variety type. An interaction between season and trait was observed for predicted neutral detergent fiber digestibility after 30 h of incubation in rumen fluid (NDFD_30h). Predicted NDFD_30h was greater for BMR sorghum in comparison to non-BMR sorghum, but BMR sorghum had slightly greater predicted NDFD_30h when grown in the spring than summer, whereas no seasonal differences were found for predicted NDFD_30h across non-BMR sorghum. An interaction between season, variety type, and trait was observed for predicted dry matter intake at 45 (DMI₄₅), 55 (DMI₅₅), and 65 (DMI₆₅) kg of milk/d. Predicted DMI₄₅ and DMI₅₅ were greater for spring BMR forage sorghum than for spring and summer non-BMR sorghum-sudangrass and were greater for spring BMR forage sorghum than for summer BMR sorghum-sudangrass. Predicted DMI₆₅ was greater for BMR forage sorghum in comparison to all non-BMR hybrids in the spring. Additionally, spring BMR forage sorghum was greater than summer sorghum-sudangrass regardless of trait. An interaction between season and sorghum variety type was observed for milk yield per megagram of forage. Milk yield per megagram of forage was greatest for spring forage sorghum. Sorghum variety type and trait selection are crucial to minimize differences in forage nutritive value of sorghum forage between seasons and improve the performance of high-producing dairy cows.

Effect of cutting height, microbial inoculation, and storage length on fermentation profile and nutrient composition of whole-plant corn silage

This study aimed to evaluate the effects of cutting height, heterofermentative microbial inoculants, and storage length on the fermentation profile and nutrient composition of whole-plant corn silage. The experiment was a completely randomized design with a 2 (cutting height) × 3 (microbial inoculation) × 5 (storage length) factorial arrangement of treatments. Corn forage was harvested at two cutting heights: either 25 cm (REG) or 65 cm (HI). Then, forage was inoculated with one of three microbial inoculants: 1) 300,000 CFU/g of fresh forage of Pediococcus acidilactici DSM 16243, Lentilactobacillus buchneri DSM 12856, and L. diolivorans DSM 32074 (LBLD; Bonsilage Speed inoculant, Provita Supplements Inc., Mendota Heights, MN), 2) 500,000 CFU/g of fresh forage of Lactiplantibacillus plantarum DSM 12837 and Lentilactobacillus buchneri DSM 16774 (LPLB; Bonsilage Corn + WS inoculant, Provita Supplements Inc., Mendota Heights, MN), or 3) distilled water (CON). Lastly, forage was randomly assigned to ferment for 5, 7, 14, 28, or 56 d of storage in vacuum-sealed bags. Silage pH was affected by a three-way interaction (P = 0.01), where CON treatments decreased continually over time while LPLB and LBLD began to increase at later storage lengths. Acetic acid concentration was greater (P = 0.001) in LPLB and LBLD than CON silage after 56 d of storage. Silage treated with LBLD did not have detectable levels of propionic acid (P &gt; 0.05), although 1-propanol concentration was greater (P = 0.001) in LBLD treatments after 56 d of storage. The concentrations of total acids and acetic acid were greater (P = 0.01 and P = 0.001, respectively) for REG silage compared to HI. Additionally, HI silage had greater (P = 0.001 and P = 0.001, respectively) concentrations of dry matter (DM) and starch, while neutral detergent fiber (aNDF) and lignin concentrations were lower (P = 0.001 and P = 0.001, respectively) in HI silage compared to REG silage. Lastly, HI silage had a greater (P = 0.001) NDF digestibility than REG silage. The results of this study demonstrate that increasing cutting height can improve nutrient composition of whole-plant corn silage. Additionally, results demonstrate heterofermentative microbial inoculants can be used to shift silage fermentation to the production of lactic and acetic acids.

Dehydrated cashew apple in different grinding sizes to sheep

The cashew pseudo fruit can be used to animal feeding in tropical and subtropical countries as Brazil, Ivory Coast and Vietnam. Thus, our objective was to evaluate the intake, digestibility of nutrients and nitrogen balance of dehydrated cashew apple by-product to sheep. The experiment was carried out with 24 sheep in a completely randomized design with the treatments distributed in a 4 x 2 factorial scheme to test the inclusion (11, 21, 28 and 33% dry matter basis) and the grinding sizes (3 and 19 mm diameter) of dehydrated cashew apple by-product. To grinding sizes there was no effect to intake and digestibility, suggesting the use of dehydrated cashew apple by-product either finely or coarsely milled. The inclusion up to 33% of dehydrated cashew apple by-product inclusion did not affect voluntary intake and nitrogen balance. However, when including above 21%, there was a reduction of ether extract digestibility and more than 28% reduced dry matter and organic matter digestibility.

Genetics and nutrition impacts on herd productivity in the Northern Australian beef cattle production cycle

Genetics and nutrition drive herd productivity due to significant impacts on all components of the beef cattle production cycle. In northern Australia, the beef production system is largely extensive and relies heavily on tropical cattle grazing low quality, phosphorus-deficient pastures with seasonal variations in nutritive value. The existing feedlots are predominantly grain-based; providing high-energy rations, faster turn-off and finishing of backgrounded cattle to meet market specifications. This review focusses on the beef cattle production cycle components of maternal nutrition, foetal development, bull fertility, post-natal to weaning, backgrounding, feedlotting, rumen microbes and carcass quality as influenced by genetics and nutrition. This student-driven review identified the following knowledge gaps in the published literature on northern Australian beef cattle production cycle: 1. Long-term benefits and effects of maternal supplementation to alter foetal enzymes on the performance and productivity of beef cattle; 2. Exogenous fibrolytic enzymes to increase nutrient availability from the cell wall and better utilisation of fibrous and phosphorus deficient pasture feedbase during backgrounding; 3. Supplementation with novel encapsulated calcium butyrate and probiotics to stimulate the early development of rumen papillae and enhance early weaning of calves; 4. The use of single nucleotide polymorphisms as genetic markers for the early selection of tropical beef cattle for carcass and meat eating quality traits prior to feedlotting; The review concludes by recommending future research in whole genome sequencing to target specific genes associated with meat quality characteristics in order to explore the development of breeds with superior genes more suited to the North Australian beef industry. Further research into diverse nutritional strategies of phosphorus supplementation and fortifying tropically adapted grasses with protein-rich legumes and forages for backgrounding and supplementing lot-fed beef cattle with omega-3 oil of plant origin will ensure sustainable production of beef with a healthy composition, tenderness, taste and eating quality.

Improving crude protein and methionine production, selective lignin degradation and digestibility of wheat straw by Inonotus obliquus using response surface methodology

BACKGROUND

To date, fungus-assisted pretreatment of agricultural residue has not become the preferred method to produce protein-enriched and ruminally digestible animal feed because of low time efficiency of fungal delignification and protein production, i.e. the long solid-state fermentation period, and because of laccase as a potential inhibitor of cellulose activity. In this study, response surface methodology was employed to optimize the parameters in the process of producing nutritious animal feed from wheat straw with Inonotus obliquus pretreatment.

RESULTS

The mineral salt solution containing (w/v) (NH₄ )₂ SO₄ 1%, MgSO₄ ·7H₂ O 0.03%, KH₂ PO₄ 0.011%, Tween-80 0.4%, and corn starch 10% with pH of 7.4 was optimized. Inonotus obliquus rapidly and completely colonized on wheat straw with an ergosterol content of 280 μg g^-1 dry matter, consuming 45% of lignin after 15 days of fermentation, producing maximums of lignin peroxidase (1729 IU g^-1 ), manganese peroxidase (610 IU g^-1 ) and laccase (98 IU g^-1 ) on days 5, 15, and 25, respectively. The crude protein (102.4 g kg^-1 ) of 15-day fermented wheat straw increased by ~132%. After hydrolysis, the essential protein-bound amino acids (15.3 g kg^-1 ) increased by ~47%, within which Met and Lys measured ~1070% and ~60% higher. The treatment with I. obliquus also improved the in vitro gas production after 72 h (IVGP₇₂ ) of wheat straw to 178.8 mL g^-1 organic matter (~43% increase).

CONCLUSION

For the first time, we found that I. obliquus is an effective white rot fungus turning wheat straw into ruminally digestible animal feed without laccase inhibitor.

Effects of lignocellulolytic enzymes on the fermentation profile, chemical composition, and in situ ruminal disappearance of whole-plant corn silage

The objective of this study was to examine the enzyme activities of an enzymatic complex produced by Pleurotus ostreatus in different pH and the effects of adding increased application rates of this enzymatic complex on the fermentation profile, chemical composition, and in situ ruminal disappearance of whole-plant corn silage (WPCS) at the onset of fermentation and 30 d after ensiling. The lignocellulolytic enzymatic complex was obtained through in vitro cultivation of P. ostreatus. In the first experiment, the activities of laccase, lignin peroxidase (LiP), manganese peroxidase, endo- and exo-glucanase, xylanase, and mannanase were determined at pH 3, 4, 5, and 6. In the second experiment, five application rates of enzymatic complex were tested in a randomized complete block design (0, 9, 18, 27, and 36 mg of lignocellulosic enzymes/kg of fresh whole-plant corn [WPC], corresponding to 0, 0.587, 1.156, 1.734, and 2.312 g of enzymatic complex/kg of fresh WPC, respectively). There were four replicates per treatment (vacuum-sealed bags) per opening time. Bags were opened 1, 2, 3, and 7 d after ensiling (onset of fermentation period) and 30 d after ensiling to evaluate the fermentation profile, chemical composition, and in situ dry matter and neutral fiber detergent disappearance of WPCS. Laccase had the greatest activity at pH 5 (P < 0.01), whereas manganese peroxidase and LiP had the greatest activity at pH 4 (P < 0.01; P < 0.01). There was no effect of the rate of application of enzymatic complex, at the onset of fermentation, on the fermentation profile (P > 0.21), and chemical composition (P > 0.36). The concentration of water-soluble carbohydrate quadratically decreased (P < 0.01) over the ensiling time at the onset of fermentation, leading to a quadratic increase of lactic acid (P = 0.02) and a linear increase of acetic acid (P = 0.02) throughout fermentation. Consequently, pH quadratically decreased (P < 0.01). Lignin concentration linearly decreased (P = 0.04) with the enzymatic complex application rates at 30 d of storage; however, other nutrients and fermentation profiles did not change (P > 0.11) with the enzymatic complex application rates. Addition of lignocellulolytic enzymatic complex from P. ostreatus cultivation to WPC at ensiling decreased WPCS lignin concentration 30 d after ensiling; however, it was not sufficient to improve in situ disappearance of fiber and dry matter.

Effect of replacing barley silage with calcium oxide-treated barley straw on rumen fermentation, rumen microbiota, nutrient digestibility, and growth performance of finishing beef cattle

Effect of calcium oxide (CaO) treatment of barley straw and salt on rumen fermentation, microbiota, digestibility, growth, and carcass quality of cattle was assessed. A replicated 4 × 4 Latin square metabolism experiment was conducted using eight heifers fed a wheat finishing diet with barley silage (B-SIL), barley straw (B-S), or 5.0% CaO-treated barley straw (CaOS) with or without NaCl (CaOS-NS). Growth over 115 d was assessed using 75 individually housed steers fed the above diets and an additional diet (I-CaOS), where CaO was added to straw just before feeding. There was no effect (P ≥ 0.08) of diet on rumen fermentation, digestibility, or carcass quality, although CaO decreased (P < 0.001) maximum pH and retained Na was decreased (P < 0.05) by CaOS-NS. Rumen bacterial abundance was altered (P ≤ 0.05) by diet. The average daily gain (ADG) of B-SIL and CaOS-NS steers was 14.1% greater (P ≤ 0.05) than BS and CaOS steers, whereas the gain:feed of CaOS-NS steers was 14.2% greater (P ≤ 0.05) than B-S and CaOS steers. Steers fed I-CaO had similar ADG and gain:feed to other treatments. CaO-treated straw without NaCl could replace barley silage in wheat diets, without compromising digestibility or growth in steers.

Rumen Fermentation, Digestive Enzyme Activity, and Bacteria Composition between Pre-Weaning and Post-Weaning Dairy Calves

Simple Summary

Weaning is very important for young ruminants. At this stage, calves’ main source of nutrients is transferred from milk into solid feed, such as starter and roughage. At the same time, the rumen function of calves undergoes tremendous changes, such as bacteria, which are the main players in rumen function. Our research found that the rumen bacteria network of post-weaning calves was more complex. The fermentation end products, such as acetate, propionate, and butyrate, were higher in the post-weaning calves than the pre-weaning group. However, digestive enzymes such as protease, carboxymethyl cellulase, cellobiohydrolase, and glucosidase were lower in the post-weaning calves than the pre-weaning calves. These findings provided useful information for reference regarding the feeding management of calves.

Abstract

To better understand the transition of rumen function during the weaning period in dairy calves, sixteen Holstein dairy calves were selected and divided into two groups: pre-weaning (age = 56 ± 7 day, n = 8) and post-weaning (age = 80 ± 6 day, n = 8). The rumen fluid was obtained by an oral gastric tube. The rumen fermentation profile, enzyme activity, bacteria composition, and their inter-relationship were investigated. The results indicated that the post-weaning calves had a higher rumen acetate, propionate, butyrate, and microbial crude protein (MCP) than the pre-weaning calves (p < 0.05). The rumen pH in the post-weaning calves was lower than the pre-weaning calves (p < 0.05). The protease, carboxymethyl cellulase, cellobiohydrolase, and glucosidase in the post-weaning calves had a lower trend than the pre-weaning calves (0.05 < p < 0.1). There was no difference in α and β diversity between the two groups. Linear discriminant analysis showed that the phylum of Fibrobacteres in the post-weaning group was higher than the pre-weaning group. At the genus level, Shuttleworthia, Rikenellaceae, Fibrobacter, and Syntrophococcus could be worked as the unique bacteria in the post-weaning group. The rumen bacteria network node degree in the post-weaning group was higher than the pre-weaning group (16.54 vs. 9.5). The Shuttleworthia genus was highly positively correlated with MCP, propionate, total volatile fatty acid, glucosidase, acetate, and butyrate (r > 0.65, and p < 0.01). Our study provided new information about the rumen enzyme activity and its relationship with bacteria, which help us to better understand the effects of weaning on the rumen function.

Enzymatic effects of Pleurotus ostreatus spent substrate on whole-plant corn silage and performance of lactating goats

Pleurotus ostreatus (oyster mushroom) synthesizes enzymes that degrade lignin, cellulose, and hemicellulose. The objectives of this study were to evaluate the effect of Pleurotus ostreatus spent substrate (POSS) on whole-plant corn silage (WPCS) chemical composition, antioxidant capacity, lignin monomers, and in vitro digestibility, as well as the performance of lactating goats fed corn silage treated with different levels of POSS. In experiment 1, 4 levels of lignocellulolytic enzymes were tested in a complete randomized design: 0, 10, 20, and 30 mg of lignocellulosic enzymes per kilogram of fresh matter, 4 replicates per treatment (vacuum-sealed bags). The bags were opened 60 d after ensiling. In experiment 2, corn silage treated with 3 enzyme levels (0, 10, or 30 mg/kg of fresh matter) was fed to lactating goats as part of the total mixed ration. Nine lactating Saanen goats (62.68 ± 7.62 kg BW; 44 ± 8 d in milk; 2.91 ± 0.81 kg of milk/day, mean ± SD) were assigned to three 3 × 3 Latin squares. Data were analyzed using the GLIMMIX procedure of SAS (version 9.4, SAS Institute Inc.), and means were compared by linear and quadratic orthogonal contrast. In experiment 1, neutral detergent fiber (NDF), acid detergent fiber (ADF), lignin, and cellulose quadratically decreased in the WPCS treated with POSS. At the nadir point, POSS decreased NDF by 14.1%, ADF by 19.5%, lignin by 9.07%, and cellulose by 22.1% compared with the untreated silage. Therefore, POSS led to a quadratic increase in in vitro dry matter digestibility of WPCS (+8.88% at the vertex) compared with the untreated silage. In experiment 2, POSS quadratically increased the in vivo total-tract ADF digestibility. Also, the concentration of polyphenols in the milk of goats linearly increased with the addition of POSS, and no differences were observed among treatments for milk yield and composition. In summary, adding 10 mg of lignocellulolytic enzymes from POSS per kilogram of fresh matter of whole-plant corn at ensiling had a more evident reduction in lignin and cellulose concentration, leading to greater in vitro digestibility, as well as greater in vivo ADF digestibility; however, milk yield was not different among treatments.

The multi-level ammoniation on the digestibility of palm press fiber

Objective:

This research aimed to study the multi-level ammoniation on the digestibility of palm press fiber (PPF) through in vitro methods.

Materials and Methods:

This research was determined using a complete randomized design of three ammoniation treatments on PPF with three replications: (1) untreated PPF (Con), (2) ammonia treatment 4% (A-4), and (3) ammonia multi-levels of 6%, 4%, and 2% (A-Mul).

Results:

The results showed a significant effect on the chemical composition of feed in the A-Mul treatment compared to Con (p < 0.05) and a non-significant effect when compared to the A-4 treatment. Overall, the content of crude protein, ether extract, and crude fiber in the A-Mul treatment increased. Except in the dry matter (DM), neutral detergent fiber and acid detergent fiber decreased. The results of the in vitro analysis showed an increase in digestibility of DM, Organic matter digestibility, N-NH₃, and volatile fatty acids (VFA) in ammoniation treatment. N-NH₃ and VFA showed non-significant differences between treatments A-4 and A-Mul (p > 0.05).

Conclusion:

Multi-level ammoniation has affected the loosening of the fiber fraction bonding in the PPF, thereby changing the value of the chemical composition and the digestibility of PPF. Multi-level ammonia can be used as an alternative to processing high-fiber feed.

Seasonal Variations of the Nutritive Value and Phytotherapeutic Potential of Cladium mariscus L. (Pohl.) Targeting Ruminant's Production

In our endeavor to identify salt-tolerant plants with potential veterinary uses in ruminants' production strategies, we focused on Cladium mariscus L. Pohl (sawgrass), due to its high total phenolic and tannin content, anti-radical properties, and ethnomedicinal uses. Aerial parts were collected along the year in Southern Portugal and evaluated for the nutritional profile and in vitro organic matter digestibility (IVOMD), aiming for its use as feed. Acetone extracts were appraised for total contents in phenolics (TPC), flavonoids (TFC), and tannins (CTC), as well as the chemical composition by HPLC-DAD and in vitro antioxidant and anti-inflammatory properties, targeting its exploitation as phytotherapeutic products. Sawgrass biomass has a limited nutritive value, due to its high neutral detergent fiber (NDF; 596-690 g kg^-1 dry matter (DM)) and acid detergent fiber (ADF; 330-418 g kg^-1 DM) contents, low crude protein (51.8-87.3 g kg^-1 DM) and IVOMD (172-317 g kg^-1 organic matter (OM)). Despite differences among seasons, the mineral profile was adequate. The extracts were rich in TPC (88-112 mg g^-1), CTC (115-169 mg g^-1), and TFC (18.5-20.2 mg g^-1), and displayed significant antioxidant capacity, particularly in summer and autumn, whilst no seasonal influence was detected for anti-inflammatory properties (30% reduction of nitric oxide production). Eleven phenolics were quantified: chlorogenic, ferulic, and syringic acids were the most abundant, especially in the autumn sample. Overall, despite the low nutritional interest, sawgrass extracts hold the potential as a source of antioxidant and anti-inflammatory phenolic compounds.

Effects of harvest date and grass species on silage cell wall components and lactation performance of dairy cows

This study evaluated the effect of harvest date and forage species on the concentration of hydroxycinnamic acids in silage and its relationship to dairy cow performance. Tall fescue and timothy were harvested at a regular date on June 27 and July 8, respectively, or at a late date on July 8 and 25, respectively, in the first regrowth. Forage was treated with a salt-based additive and ensiled in hard-pressed round bales. Forty-seven lactating dairy cows were used in a block design. Cows received 1 of 4 treatments: (1) tall fescue harvested at regular date (RTF), (2) timothy harvested at regular date (RTI), (3) tall fescue harvested at late date (LTF), and (4) timothy harvested at late date (LTI). Diets were formulated to have the same forage-to-concentrate ratio (46:54 on a dry matter basis). Harvesting at late date increased fiber components, but only for timothy, where LTI contained greater neutral detergent fiber, acid detergent fiber, and acid detergent lignin concentrations than the other silages. Concentrations of hydroxycinnamic acids were affected by forage species, where concentrations of esterified ferulic acid and p-coumaric acid were greater for tall fescue silages than for timothy silages. Cows fed the RTI diet showed the greatest intakes of dry matter, organic matter, and crude protein. Feeding diets containing timothy silages increased milk yield and energy-corrected milk yield compared with tall fescue diets when averaged over harvest dates. Cows fed the RTI diet had greater milk protein yield than cows fed the RTF and LTF diets, and milk lactose yield was greater for cows fed diets containing timothy silage compared with tall fescue silage when averaged over harvest dates. Cows fed the LTF diet showed greater urinary N excretion compared with the LTI diet, but RTI showed the lowest urinary N and urea N excretions when calculated as percent of N intake. Cows fed diets containing timothy silage excreted more uric acid than cows fed tall fescue diets. Allantoin excretion was greater for cows eating the RTI and LTI diets compared with cows eating the RTF diet. Cows fed the RTI diet had a greater estimated microbial N flow and a greater excretion of hippuric acid than the RTF and LTF groups. In conclusion, besides the effect of harvest date on increasing the fiber components of timothy, concentrations of hydroxycinnamic acids were mainly affected by forage species; consequently, milk production was only affected by forage species. This indicates that hydroxycinnamic acids, such as ferulic acid, which cross-links to glucuronoarabinoxylans, was a major factor regulating milk production of cows fed tall fescue- and timothy silage-based diets, where lower hydroxycinnamic acid concentrations were responsible for greater milk yield.

Strategies to improve the efficiency of beef cattle production

Globally, there are approximately one billion beef cattle, and compared with poultry and swine, beef cattle have the poorest conversion efficiency of feed to meat. However, these metrics fail to consider that beef cattle produce high-quality protein from feeds that are unsuitable for other livestock species. Strategies to improve the efficiency of beef cattle are focusing on operational and breeding management, host genetics, functional efficiency of rumen and respiratory microbiomes, and the structure and composition of feed. These strategies must also consider the health and immunity of the herd as well as the need for beef cattle to thrive in a changing environment. Genotyping can identify hybrid vigor with positive consequences for animal health, productivity, and environmental adaptability. The role of microbiome–host interactions is key in efficient nutrient digestion and host health. Microbial markers and gene expression patterns within the rumen microbiome are being used to identify hosts that are efficient at fibre digestion. Plant breeding and processing are optimizing the feed value of both forages and concentrates. Strategies to improve the efficiency of cattle production are a prerequisite for the sustainable intensification needed to satisfy the future demand for beef.

Pelleting of a Total Mixed Ration Affects Growth Performance of Fattening Lambs

Feeding pelleted total mixed rations (TMR) instead of traditional loose concentrate plus forage to fattening lambs is an emerging practice. This study aimed to determine the effects of feeding pelleted TMR to fattening lambs on feed intake behaviour, growth performance, feed digestion, rumen fermentation characteristics, rumen microbial community, serum parameters, slaughter performance, meat quality, and the economic outcome. Two physical forms (pelleted vs. un-pelleted) of TMR composed of the same ingredients with the same particle sizes were compared in three animal experiments. Feed intake and average daily gain were higher when the TMR was pelleted, but apparent total tract digestibility of nutrients (organic matter, crude protein, neutral detergent fibre, acid detergent fibre, and ether extract) and serum parameters were not affected and apparent total tract dry matter digestibility was slightly lower. Feeding pelleted TMR increased total short-chain fatty acid concentration and decreased rumen pH. Rumen microbial community was not affected by the physical form of the TMR at phylum level but changed slightly at genus level. Liveweight at slaughter and hot carcass weight were higher for lambs fed the pelleted compared to the un-pelleted TMR, while dressing percentage and meat quality were not affected. In conclusion, feeding pelleted TMR improves growth performance of fattening lambs mainly due to an increase in feed intake. Feeding pelleted TMR is a feasible strategy for intensive lamb fattening operations.

Genome-Wide Association Studies Identifying Multiple Loci Associated With Alfalfa Forage Quality

Autotetraploid alfalfa is a major hay crop planted all over the world due to its adaptation in different environments and high quality for animal feed. However, the genetic basis of alfalfa quality is not fully understood. In this study, a diverse panel of 200 alfalfa accessions were planted in field trials using augmented experimental design at three locations in 2018 and 2019. Thirty-four quality traits were evaluated by Near Infrared Reflectance Spectroscopy (NIRS). The plants were genotyped using a genotyping by sequencing (GBS) approach and over 46,000 single nucleotide polymorphisms (SNPs) were obtained after variant calling and filtering. Genome-wide association studies (GWAS) identified 28 SNP markers associated with 16 quality traits. Among them, most of the markers were associated with fiber digestibility and protein content. Phenotypic variations were analyzed from three locations and different sets of markers were identified by GWAS when using phenotypic data from different locations, indicating that alfalfa quality traits were also affected by environmental factors. Among different sets of markers identified by location, two markers were associated with nine traits of fiber digestibility. One marker associated with lignin content was identified consistently in multiple environments. Putative candidate genes underlying fiber-related loci were identified and they are involved in the lignin and cell wall biosynthesis. The DNA markers and associated genes identified in this study will be useful for the genetic improvement of forage quality in alfalfa after the validation of the markers.

Recombinant Technologies to Improve Ruminant Production Systems: The Past, Present and Future

The use of recombinant technologies has been proposed as an alternative to improve livestock production systems for more than 25 years. However, its effects on animal health and performance have not been described. Thus, understanding the use of recombinant technology could help to improve public acceptance. The objective of this review is to describe the effects of recombinant technologies and proteins on the performance, health status, and rumen fermentation of meat and milk ruminants. The heterologous expression and purification of proteins mainly include eukaryotic and prokaryotic systems like Escherichia coli and Pichia pastoris. Recombinant hormones have been commercially available since 1992, their effects remarkably improving both the reproductive and productive performance of animals. More recently the use of recombinant antigens and immune cells have proven to be effective in increasing meat and milk production in ruminant production systems. Likewise, the use of recombinant vaccines could help to reduce drug resistance developed by parasites and improve animal health. Recombinant enzymes and probiotics could help to enhance rumen fermentation and animal efficiency. Likewise, the use of recombinant technologies has been extended to the food industry as a strategy to enhance the organoleptic properties of animal-food sources, reduce food waste and mitigate the environmental impact. Despite these promising results, many of these recombinant technologies are still highly experimental. Thus, the feasibility of these technologies should be carefully addressed before implementation. Alternatively, the use of transgenic animals and the development of genome editing technology has expanded the frontiers in science and research. However, their use and implementation depend on complex policies and regulations that are still under development.

Feeding Fungal-Pretreated Corn Straw Improves Health and Meat Quality of Lambs Infected with Gastrointestinal Nematodes

Simple Summary

Non-chemical strategies to control gastrointestinal nematode (GINs) infections are urgently needed to support the sustainable development of the livestock industry. The potential anti-parasitic properties in fungal-pretreated corn straw on health and meat quality of lambs infected with GINs were investigated in this study. In summary, feeding fungal-pretreated corn straw improved health and meat quality, including meat color and tenderness. Improved meat traits were attributed to fungal-pretreated corn straw providing additional dietary protein for lambs and secreting some nematicidal metabolites to repel GINs, which increased PCV and plasma iron content of lambs and reversed negative effects of GINs on meat quality.

Abstract

Infections with gastrointestinal nematodes (GIN) adversely affect meat color in lambs. Although white-rot fungi (WRF) pretreatment increases nutritional value and fiber digestion of corn straw for lambs, whether it can improve meat quality of lambs infected with GINs is unknown. The objective of this experiment was to study effects of feeding WRF-pretreated corn straw on the health and meat quality of lambs infected with GINs. Sixteen healthy Ujumqin lambs were orally drenched with 3rd-stage GINs larvae and randomly divided into two dietary treatments of control (CON) and WRF diets for 70 days of feeding. Results showed that feeding WRF-pretreated corn straw decreased L* and b* values (p < 0.05) and increased a* value (p < 0.01) of both longissimus thoracis et lumborum (LTL) and semimembranosus (SM) muscles of lambs infected with GINs. Feeding WRF-pretreatment corn straw decreased fecal egg count (p = 0.014) and increased packed cell volume (p = 0.013) of lambs from 28 d of feeding and increased plasma iron content (p = 0.008) of lambs from 56 d of the feeding. Feeding WRF-pretreatment corn straw decreased myosin heavy-chain (MyHC)-I (p = 0.032) and MyHC-IIα (p = 0.025) content in LTL muscle and MyHC-I (p = 0.022) and MyHC-IIβ (p = 0.048) in SM muscle of lambs. In conclusion, although there were no significant changes in the content of most amino acids or increased intensity of better flavor compounds, meat quality and health of lambs infected with GINs was significantly improved by feeding WRF-pretreated corn straw due to increased PCV and meat color and tenderness.

Technological variables influencing the growth and stability of a silage inoculant based on spray-dried lactic acid bacteria

AIMS

To investigate the influence of different culture media and fermentation conditions on growth performance and viability of three lactic acid bacteria (LAB) strains with potential as silage inoculants, and to optimize spray-drying in order to enhance survival to dehydration and storage stability.

METHODS AND RESULTS

In house-formulated MRS was a suitable low-cost culture medium for Lactobacillus plantarum Hv75, Pediococcus acidilactici 3903 and L. buchneri B463. Uncontrolled pH biomass production conferred enhanced stability during storage at 4°C after spray-drying. The use of whey protein concentrate 35 (WPC)-maltodextrin (M) as matrix, inlet temperature of 145-150°C and air flow rate of 601 l h^-1 was adequate for the production of dehydrated LAB. According to the desirability function, at this optimized condition, moisture content, yield and solubility were predicted to be 3·96, 73·68 and 90·36% respectively. Those conditions also showed a decrease of 0·855 log CFU per gram after drying, no loss in viability at 4°C for 6 months and 1 log CFU per gram reduction at 25°C.

CONCLUSIONS

Stable and economically feasible dehydrated LAB cultures were obtained using alternative culture media, fermentation under uncontrolled pH and optimizing spray-drying process conditions through the desirability function method.

SIGNIFICANCE AND IMPACT OF THE STUDY

Our results can be utilized for efficient production and commercialization of several dry LAB.

Effect of ammonia fiber expansion-treated wheat straw and a recombinant fibrolytic enzyme on rumen microbiota and fermentation parameters, total tract digestibility, and performance of lambs

The objective of this study was to evaluate the effect of ammonia fiber expansion (AFEX)-treated wheat straw pellets and a recombinant fibrolytic enzyme on the rumen microbiome, rumen fermentation parameters, total tract diet digestibility, and performance of lambs. Eight rumen cannulated wethers and 60 lambs (n = 15 per diet, 8 rams and 7 ewes) were used in a replicated 4 × 4 Latin square design digestibility study and a complete randomized growth performance study, respectively. Four treatment diets were arranged in a 2 × 2 factorial structure with AFEX wheat straw (0% or 30% AFEX straw pellets on a dietary DM basis replacing alfalfa hay pellets) and fibrolytic enzyme (with or without XYL10C, a β-1,4-xylanase, from Aspergillus niger) as main factors. Enzyme was applied at 100 mg/kg of diet DM, 22 h before feeding. Rumen bacteria diversity Pielou evenness decreased (P = 0.05) with AFEX compared with the control diet and increased (P < 0.01) with enzyme. Enzyme increased (P ≤ 0.02) the relative abundancies of Prevotellaceae UCG-004, Christensenellaceae R-7 group, Saccharofermentans, and uncultured Kiritimatiellaeota. Total protozoa counts were greater (P ≤ 0.04) in the rumen of lambs fed AFEX compared with control, with enzyme reducing (P ≤ 0.05) protozoa counts for both diets. Digestibility of DM did not differ (P > 0.10) among diets, but digestibility of CP was reduced (P = 0.001), and digestibility of NDF and ADF increased (P < 0.05) as AFEX replaced alfalfa. Compared with control, AFEX promoted greater DMI (P = 0.003) and improved ADG up to 42 d on feed (P = 0.03), but not (P = 0.51) over the full ~94-d experiment. Consequently, overall G:F was reduced (P = 0.04) for AFEX when compared with control (0.188 vs. 0.199), but days on feed were lower (P = 0.04) for AFEX (97 vs. 91 d). Enzyme improved DMI of AFEX up to day 70 (P = 0.01), but did not affect DMI of the control diet. Enzyme addition improved ADG of lambs fed both diets in the first 28 d (P = 0.02), but not over the entire feeding period (P ≥ 10). As a result, G:F was improved with enzyme for the first 28 d (P = 0.04), but not overall (P = 0.45). This study shows that AFEX-treated wheat straw can replace alfalfa hay with no loss in lamb growth performance. Additionally, the enzyme XYL10C altered the rumen microbiome and improved G:F in the first month of the feeding.

Liquid hot water treatment of rice straw enhances anaerobic degradation and inhibits methane production during in vitro ruminal fermentation

Liquid hot water (LHW) treatment can be used to disrupt the fiber structure of rice straw. This in vitro ruminal batch culture study investigated the effect of LHW treatment on feed degradation, methane (CH₄) production, and microbial populations. Rice straw was treated by LHW, and in vitro ruminal fermentation was performed using an automatic system with 72 h of incubation. Scanning electron microscopy showed that LHW treatment disrupted the physical structure of rice straw. Liquid hot water treatment decreased neutral detergent fiber and hemicellulose contents of the rice straw and increased neutral detergent solubles, water-soluble carbohydrates, and arabinose contents. Liquid hot water treatment increased dry matter degradation and volatile fatty acid concentration and decreased the acetate:propionate ratio, CH₄ production, hydrogen accumulation, neutral detergent fiber degradation, and populations of protozoa, fungi, and cellulolytic bacteria. In summary, LHW treatment disrupted the cellulose-hemicellulose-lignin structure matrix of rice straw, leading to increased substrate degradability and decreased CH₄ production. Therefore, the LHW treatment is a potential strategy to improve the nutritive value of forage such as rice straw and decrease the CH₄ emissions in ruminants.

Effect of alkaline and sonication pretreatments on the rumen degradability of date palm seeds

The main objective of this research was to evaluate the effects of chemical treatment and sonication (ultrasound) processing on the fiber composition and rumen degradability of date palm seeds (DPS). In the first trial, the effects of incubation or sonication in 4% sodium hydroxide (NaOH) on DPS fiber content and ruminal degradability were evaluated. Relative to untreated seeds, the ruminal degradability of DPS neutral detergent fiber (NDF) and organic matter (OM) increased (P < 0.05) for the treated seeds and were highest (P < 0.05) for the sonicated seeds. Relative to untreated seeds, the hemicellulose and lignin content were lower (P < 0.05) for the sonicated seeds, while the cellulose content was higher (P < 0.05) for the incubated seeds. In the second trial, the effects of subjecting DPS to different sonication times (5, 10, 20, and 30 min) were evaluated. The degradability of seeds' NDF and OM were greater (P < 0.05) for the sonicated than unsonicated seeds. The highest NDF degradability was seen after 30 min sonication, whereas the OM degradability was not affected by sonication time (P > 0.05). In the third trial, the effects of subjecting DPS to sonication in different NaOH solutions (1%, 2%, 4% NaOH) were evaluated. Relative to untreated seeds, the rumen degradability of seeds' NDF and OM increased with all NaOH concentrations but was highest (P < 0.05) with the 4% NaOH. In conclusion, our results showed that treating DPS with 4% NaOH increased the seeds' ruminal degradability, and subjecting DPS to sonication further improved their degradability in the rumen.