Postbiotics from Saccharomyces cerevisiae fermentation stabilize microbiota in rumen liquid digesta during grain-based subacute ruminal acidosis(SARA) in lactating dairy cows

Background Subacute ruminal acidosis(SARA)is a common metabolic disorder of high yielding dairy cows,and it is associated with dysbiosis of the rumen and gut microbiome and host inflammation.This study evaluated the impact of two postbiotics from Saccharomyces cerevisiae fermentation products(SCFP)on rumen liquid associated microbiota of lactating dairy cows subjected to repeated grain-based SARA challenges.A total of 32 rumen cannulated cows were randomly assigned to 4 treatments from 4 weeks before until 12 weeks after parturition.Treatment groups included a Control diet or diets supplemented with postbiotics(SCFPa,14 g/d Original XPC;SCFPb-1X,19 g/d Nutri Tek;SCFPb-2X,38 g/d Nutri Tek,Diamond V,Cedar Rapids,IA,USA).Grain-based SARA challenges were conducted during week 5(SARA1)and week 8(SARA2)after parturition by replacing 20%DM of the base total mixed ration(TMR)with pellets containing 50%ground barley and 50%ground wheat.Total DNA from rumen liquid samples was subjected to V3–V416S r RNA gene amplicon sequencing.Characteristics of rumen microbiota were compared among treatments and SARA stages.Results Both SARA challenges reduced the diversity and richness of rumen liquid microbiota,altered the overall composition(β-diversity),and its predicted functionality including carbohydrates and amino acids metabolic pathways.The SARA challenges also reduced the number of significant associations among different taxa,number of hub taxa and their composition in the microbial co-occurrence networks.Supplementation with SCFP postbiotics,in particular SCFPb-2X,enhanced the robustness of the rumen microbiota.The SCFP supplemented cows had less fluctuation in relative abundances of community members when exposed to SARA challenges.The SCFP supplementation promoted the populations of lactate utilizing and fibrolytic bacteria,including members of Ruminococcaceae and Lachnospiraceae,and also increased the numbers of hub taxa during non-SARA and SARA stages.Supplementation with SCFPb-2X prevented the fluctuations in the abundances of hub taxa that were positively correlated with the acetate concentration,andα-andβ-diversity metrics in rumen liquid digesta.Conclusions Induction of SARA challenges reduced microbiota richness and diversity and caused fluctuations in major bacterial phyla in rumen liquid microbiota in lactating dairy cows.Supplementation of SCFP postbiotics could attenuate adverse effects of SARA on rumen liquid microbiota.

Influence of Production Factors on the Physico-Chemical Characteristics of Fermented Cassava Dough and Sensory Evaluation of Attieke

Attieke is an Ivorian semolina which obtained by fermenting, pressing and steaming cassava dough. Attieke production remains a traditional activity carried out by less literate women. However, perceived differences in measurable factors and attieke qualities require an investigation of their influence on the characteristics of the pressed dough and attieke. The aim of this study is to improve the quality of the dough in relation to that of the attieke produced. The experiment was carried out on 4 production factors, namely the type of boiled or braised ferment, the incorporation rate of the ferment between 8 and 10%, the addition of oil from 0.1 to 1% and the fermentation time from 12 to 15 hours applied to the Improved African Cassava (IAC) variety. A complete experiment design of 16 samples of fermented dough and attieke was employed. These samples underwent physic-chemical analyses for the fermented dough and sensory evaluation for the attieke. It was found that, except for titratable acidity, reducing sugar content and ash content, the physico-chemical characteristics of the dough of IAC variety were significantly influenced by all production factors and their interaction. Fermentation time significantly influences 60% of the physico-chemical characteristics of the fermented dough. The type of ferment, the oil addition and the ferment rate have a significant influence at 40% of these characteristics. At the sensory level, color, acidity and grain binding with an explained variance of 34.60% were essential for the appreciation of the attieke samples. Thus, these production factors could be considered for the improvement of the fermented dough and attieke production process.

Effects of Saccharomyces cerevisiae fermentation products on performance and rumen fermentation and microbiota in dairy cows fed a diet containing low quality forage

Background： A possible option to meet the increased demand of forage for dairy industry is to use the agricultural byproducts, such as corn stover. However, nutritional value of crop residues is low and we have been seeking technologies to improve the value. A feeding trial was performed to evaluate the effects of four levels of Saccharomyces cerevisiae fermentation product（SCFP; Original XP; Diamond V） on lactation performance and rumen fermentation in mid-lactation Holstein dairy cows fed a diet containing low-quality forage. Eighty dairy cows were randomly assigned into one of four treatments： basal diet supplemented with 0, 60, 120, or 180 g/d of SCFP per head mixed with 180, 120, 60, or 0 g of corn meal, respectively. The experiment lasted for 10 wks, with the first 2 weeks for adaptation.Results： Dry matter intake was found to be similar（P 〉 0.05） among the treatments. There was an increasing trend in milk production（linear, P ≤ 0.10） with the increasing level of SCFP supplementation, with no effects on contents of milk components（P 〉 0.05）. Supplementation of SCFP linearly increased（P 〈 0.05） the N conversion, without affecting rumen pH and ammonia-N（P 〉 0.05）. Increasing level of SCFP linearly increased（P 〈 0.05） concentrations of ruminal total volatile fatty acids, acetate, propionate, and butyrate, with no difference in molar proportion of individual acids（P 〉 0.05）. The population of fungi and certain cel ulolytic bacteria（Ruminococcus albus, R. flavefaciens and Fibrobacter succinogenes）increased linearly（P 〈 0.05） but those of lactate-utilizing（Selenomonas ruminantium and Megasphaera elsdeni） and lactate-producing bacteria（Streptococcus bovis） decreased linearly（P ≤ 0.01） with increasing level of SCFP. The urinary purine derivatives increased linearly（P 〈 0.05） in response to SCFP supplementation, indicating that SCFP supplementation may benefit for microbial protein synthesis in the rumen.Conclusions： The SCFP supplementation was effective in maintaining milk persistency of mid-lactation cows receiving diets containing low-quality forage. The beneficial effect of SCFP could be attributed to improved rumen function; 1）microbial population shift toward greater rumen fermentation efficiency indicated by higher rumen fungi and cel ulolytic bacteria and lower lactate producing bacteria, and 2） rumen microbial fermentation toward greater supply of energy and protein indicated by greater ruminal VFA concentration and increased N conversion. Effects of SCFP were dose-depended and greater effects being observed with higher levels of supplementation and the effect was more noticeable during the high THI environment.

Effects of molasses on the fermentation characteristics of mixed silage prepared with rice straw, local vegetable by-products and alfalfa in Southeast China

This experiment was conducted to study the effect of molasses on the fermentation characteristics of mixed silage ensiled rice straw and vegetable by-products with alfalfa.Mixture（202 g kg^-1 dry matter（DM））consisting of rice straw,broccoli residue and alfalfa at the ratio of 5：4：1 was ensiled with three experimental treatments：（1）no additives（control）;（2）molasses at 2.5%（M1）;（3）molasses at 5%（M2）on a fresh matter basis of mixture,respectively.All treatments were packed into laboratory-scale silos,and three silos per treatment were sampled on days 1,3,5,14 and 30.The result showed that the p H value of all mixed silages decreased gradually with the time of ensiling except for the control silage,in which a significant increase（P〈0.05）on day 30 occurred.The lactic acid content increased gradually with the time of ensiling and reached the highest value on day 14,and a marked decrease（P〈0.05）was found in the control silage on day 30.The changes of acetic acid content showed similar pattern with lactic acid content.A trace amount of propionic and butyric acid contents were found in the three mixed silages during the fermentation period.Comparing to the control,M1 and M2 treatments improved the fermentation quality of mixed silages as indicated by higher（P〈0.05）lactic acid contents and lower（P〈0.05）p H and ammonia-N contents.The Flieg points also showed that M1 and M2 silages were well preserved,whereas the control silage had a bad quality.Overall,the findings of this study suggested that adding molasses could improve fermentation quality of mixed silage,and M1 was more suitable for practical application.

Effects of Selenium on Fusarium Growth and Associated Fermentation Products and the Relationship with Chondrocyte Viability

This study determined the effects of selenium on the growth of Fusorium strains and the effects of products extracted from the fungal cultures on relevant indicators of chondrocytes injury.

Application Effect of Cassava Starch Anaerobic Fermentation Liquid on Watermelon Production

In order to find out a new way for environment-friendly and resourcelized utilization of cassava starch processing wastewater, the cassava starch anaerobic fermentation liquid was applied in watermelon production, and its effects on the growth and development, yield and fruit quality of watermelon were investigated. The results showed that the cassava starch anaerobic fermentation liquid significant- ly promoted the vegetative and reproductive growth and improved the yield and fruit quality of watermelon. Compared with conventional fertilization, the application of cassava starch anaerobic fermentation both with COD concentration of 1 200 mg/L according to the amount of 150 t/hm2 promoted the growth of vines and leaves of watermelon plants, brought forward the flowering, fruiting and harvest of watermelon and significantly increased the fruit number, fruit weight, yield, fruit size, fruit shape index, soluble solid content, soluble sugar content, soluble protein content and Vita- min C content of watermelon. At the same time of improving the yield and quality of watermelon, cassava starch anaerobic fermentation liquid was turned into treasure as a liquid fertilizer. This study provides a new ideal for the yield and quality im- provement of watermelon and the wastewater treating of starch factories.

Effects of Fermentation Product Containing Phytase on Productive Performance,Egg Quality,and Phosphorous Apparent Metabolism of Laying Hens Fed Different Levels of Phosphorus

This study investigated the effects of fermentation product containing phytase （FPP） that was fermented using waste vinegar residue （WVR） as substrate from Aspergillusficuum NTG-23 on productive performance, egg quality, and phosphorus apparent metabolism of laying hens. First, 375 22-wk-old Jinghong hens were allocated into 5 treatments （5 replicates of 15 hens each） in an 8-wk experiment for evaluating the parameters of productive performance, egg quality, serum, and tibia. Experimental diets contained 4% FPP and 96% corn-soybean diet. The levels of dicalciurn phosphate （DCP） were 1.34, 1.01, 0.67, 0.34 and 0%. Next, thirty 31-wk-old Jinghong hens were fed 5 types of diets for evaluating phosphorous apparent metabolism rate. Egg productive rate, egg weight, feed conversion ratio, Haugh unit, egg albumen height, serum calcium, tibia ash, tibia ash calcium and tibia breaking strength were not different significantly among 5 treatments. The significant difference of average daily feed intake was not appeared when the DCP content of corn-soybean-FPP diet was reduced to 0.67%; the eggshell hardness, eggshell thickness and serum phosphorus were not reduced significantly until the DCP content of corn-soybean-FPP diet was reduced to 0.34%. The yolk color was improved when the laying hens fed deficient DCP corn-soybean-FPP diet. A 22.14% reduction in excreta phosphorus was observed when the laying hens fed low phosphorus （0.67% DCP） corn-soybean-FPP diet. A 30% elevation of phosphorus apparent metabolism rate was obtained when the DCP content of corn-soybean-FPP diet was decreased from 1.34 to 1.01%. The reducing cost of layer diet was totalized about 120 CNY 1000 kg1 diet when the content of DCP was 0.67% in corn-soybean-FPP diet. These results indicated that FPP could be applied in laying hen as a potential, cost-effective and rational application of WVR.

Feeding a Saccharomyces cerevisiae fermentation product improves udder health and immune response to a Streptococcus uberis mastitis challenge in mid-lactation dairy cows

Background:We aimed to characterize the protective effects and the molecular mechanisms of action of a Saccharomyces cerevisiae fermentation product(NTK)in response to a mastitis challenge.Eighteen mid-lactation multiparous Holstein cows(n=9/group)were fed the control diet(CON)or CON supplemented with 19 g/d NTK for 45 d(phase 1,P1)and then infected in the right rear quarter with 2500 CFU of Streptococcus uberis(phase 2,P2).After 36-h,mammary gland and liver biopsies were collected and antibiotic treatment started until the end of P2(9 d post challenge).Cows were then followed until day 75(phase 3,P3).Milk yield(MY)and dry matter intake(DMI)were recorded daily.Milk samples for somatic cell score were collected,and rectal and udder temperature,heart and respiration rate were recorded during the challenge period(P2)together with blood samples for metabolite and immune function analyses.Data were analyzed by phase using the PROC MIXED procedure in SAS.Biopsies were used for transcriptomic analysis via RNA-sequencing,followed by pathway analysis.Results:DMI and MY were not affected by diet in P1,but an interaction with time was recorded in P2 indicating a better recovery from the challenge in NTK compared with CON.NTK reduced rectal temperature,somatic cell score,and temperature of the infected quarter during the challenge.Transcriptome data supported these findings,as NTK supplementation upregulated mammary genes related to immune cell antibacterial function(e.g.,CATHL4,NOS2),epithelial tissue protection(e.g.IL17C),and anti-inflammatory activity(e.g.,ATF3,BAG3,IER3,G-CSF,GRO1,ZFAND2A).Pathway analysis indicated upregulation of tumor necrosis factorα,heat shock protein response,and p21 related pathways in the response to mastitis in NTK cows.Other pathways for detoxification and cytoprotection functions along with the tight junction pathway were also upregulated in NTK-fed cows.Conclusions:Overall,results highlighted molecular networks involved in the protective effect of NTK prophylactic supplementation on udder health during a subclinical mastitic event.

Identification and fermentation optimization of protopectinase-overproducing strain Aspergillus niger CD-01 for pectin production

In order to solve the citrus peel resource waste problem protopectinase-overproducing strain CD-01 for pectin production and minimize the drawbacks of chemical extraction of pectin, a was isolated from a pit soil dumped with perished orange in Changde City, Hunan Province of China. The strain CD-01 had the same morphology and 28S rRNA gene sequence （FJ184995） as that of Aspergillus niger （ATCC 64028）. It was thus identified and named as Aspergillus niger CD-01. The fermentation condition was optimized based on L9（34） orthogonal experimental design and the variances analyses. The results show that the optimal condition for producing pectin is as follows： time 36 h, temperature 35 ℃, pH 5, and urea as the nitrogen source. Under this condition, the pectin yield can reach up to 24.5%. This shows a great potential of Aspergillus niger CD-01 in pectin extraction from citrus.

Effects of brewers' spent grain protein hydrolysates on gas production, ruminal fermentation characteristics, microbial protein synthesis and microbial community in an artificial rumen fed a high grain diet

Background: Brewers' spent grain(BSG) typically contains 20% – 29% crude protein(CP) with high concentrations of glutamine, proline and hydrophobic and non-polar amino acid, making it an ideal material for producing valueadded products like bioactive peptides which have antioxidant properties. For this study, protein was extracted from BSG, hydrolyzed with 1% alcalase and flavourzyme, with the generated protein hydrolysates(AlcH and FlaH)showing antioxidant activities. This study evaluated the effects of AlcH and FlaH on gas production, ruminal fermentation characteristics, nutrient disappearance, microbial protein synthesis and microbial community using an artificial rumen system(RUSITEC) fed a high-grain diet.Results: As compared to the control of grain only, supplementation of FlaH decreased(P < 0.01) disappearances of dry matter(DM), organic matter(OM), CP and starch, without affecting fibre disappearances;while AlcH had no effect on nutrient disappearance. Neither AlcH nor FlaH affected gas production or VFA profiles, however they increased(P < 0.01) NH_3-N and decreased(P < 0.01) H_2 production. Supplementation of FlaH decreased(P < 0.01)the percentage of CH_4 in total gas and dissolved-CH_4(dCH_4) in dissolved gas. Addition of monensin reduced(P < 0.01) disappearance of nutrients, improved fermentation efficiency and reduced CH_4 and H_2 emissions.Total microbial nitrogen production was decreased(P < 0.05) but the proportion of feed particle associated(FPA) bacteria was increased with FlaH and monensin supplementation. Numbers of OTUs and Shannon diversity indices of FPA microbial community were unaffected by AlcH and FlaH;whereas both indices were reduced(P < 0.05) by monensin. Taxonomic analysis revealed no effect of AlcH and FlaH on the relative abundance(RA) of bacteria at phylum level, whereas monensin reduced(P < 0.05) the RA of Firmicutes and Bacteroidetes and enhanced Proteobacteria. Supplementation of FlaH enhanced(P < 0.05) the RA of genus Prevotella, reduced Selenomonas, Shuttleworthia, Bifidobacterium and Dialister as compared to control;monensin reduced(P < 0.05) RA of genus Prevotella but enhaced Succinivibrio.Conclusions: The supplementation of FlaH in high-grain diets may potentially protect CP and starch from ruminal degradation, without adversely affecting fibre degradation and VFA profiles. It also showed promising effects on reducing CH_4 production by suppressing H_2 production. Protein enzymatic hydrolysates from BSG using flavourzyme showed potential application to high value-added bio-products.

Fermented Dairy Products: Starter Cultures and Potential Nutritional Benefits

Fermented dairy products have long been an important component of nutritional diet. Historically, fermentation proc-ess involved unpredictable and slow souring of milk caused by the organisms inherently present in milk. However, modern microbiological processes have resulted in the production of different fermented milk products of higher nutri-tional value under controlled conditions. These products represent an important component of functional foods, and intense research efforts are under way to develop dairy products into which probiotic organisms are incorporated to make them more valuable. This article provides an overview of the different starter cultures and health benefits of fer-mented dairy products, which can be derived by the consumers through their regular intake.

Isolation and characterization of novel peptides from fermented products of Lactobacillus for ulcerative colitis prevention and treatment

Ulcerative colitis(UC)is an incurable and highly complex digestive disease affecting millions of people worldwide.Compared to the current therapeutic drugs,bioactive peptides are more promising and safe substances as functional foods or drugs for the prevention and treatment of UC.The alcohol-soluble components from fermentation broth by fresh wheat germ and apple(AC-WGAF)were found to be effective in UC prevention in dextran sulfate sodium-induced mice in vivo.Herein,4 novel peptides are identifi ed from AC-WGAF by membrane ultrafi ltration,recycling preparative high-performance liquid chromatography,and matrix-assisted laser desorption–ionization time-of-fl ight/time-of-fl ight mass spectrometry,possessing anticolitis activity via using an in vitro model.One of those peptides named T24(PVLGPVRGPFPLL)exhibited the most remarkable anti-colitis activity by preventing tight junction protein loss,maintaining epithelial barrier integrity,and promoting cell proliferation during in vitro and in vivo studies by regulating mitogen-activated protein kinase signaling pathways.Thus,T24 is a promising peptide as a functional food or novel drug for UC prevention and treatment.

Rumen methane output and fermentation characteristics of gramineous forage and leguminous forage at differing harvest dates determined using an in vitro gas production technique

An in vitro rumen gas production technique was employed to determine the methane production and fermentation characteristics of Leymus chinensis and Medicago ruthenica at differing harvest dates（May 15,May 30,June 30,July 30,August 30 and September 30）,which are sequential phases within a single continuous growth of two 10-year-old pastures.To quantify the rate of degradation and compare in vitro rumen fermentation characteristic,a logistic-exponential model,where initial gas volume was zero（LE_0）,was used to fit gas production and methane output results.Dried,milled forage samples were incubated in vitro for 72 h at 39℃ and gas production was recorded intermittently throughout the incubation and gas samples were collected to measure methane production.Results showed that there were significant interactions between species and harvest for all chemical composition variables（P〈0.001） and condensed tannin content（P〈0.001）.L.chinensis produced more total gas and methane than M.ruthenica（P〈0.001）.Both total gas and methane production decreased lineally（P〈0.001） with advancing harvest date.The degradation rates of L.chinensis and M.ruthenica harvested on September 30 were lower than those on the other harvest dates（P〈0.01）.M.ruthenica fermented fluid had higher concentration of ammonia N（P〈0.05） and molar proportions of isobutyrate（P〈0.01）,valerate（P〈0.001） and isovalerate（P〈0.01） in total volatile fatty acids than L chinensis.Furthermore,concentration of isovalerate decreased cubically with advancing harvest date（P〈0.05）.In conclusion,M.ruthenica produced less methane than L.chinensis and the total gas and methane production decreased with advancing harvest date for both species,which may be due to the changes in contents of chemical compositions and condensed tannin in forages.

Probiotics Potential of Yeast and Lactic Acid Bacteria Fermented Foods and the Impact of Processing: A Review of Indigenous and Continental Food Products

Probiotics have become essential in food safety and health discourse with interest in their availability, stability, nutrition, and health implications. In this paper, an overview of probiotics of yeast and lactic acid, bacterial fermented food is presented. Probiotics of Lactobacillus spp. and Bifidobacterium spp.’s activities and processes within the human intestinal system are examined. Yeast and lactic acid bacterial (LAB) fermented foods from classified food groups such as vegetables, cereals, and grains, soybean, milk, fish, meat, and beverages are examined. This paper focuses on probiotic (microorganism) strains identified with food and their potential health and nutrition benefits. Finally, the impact of processing parameters and non-process factors on probiotics potential in fermented food is investigated.

Optimization of Mycelial Biomass Production in Submerged Culture Fermentation of <i>Pleurotus flabellatus</i>Using Response Surface Methodology

The factors selected to optimize the productivity of Pleurotus flabellatus biomass in 250ml working volume Erlenmeyer flask were agitation rate, initial pH value and incubation temperature. The central composite design was applied to study the significant factors and the interactions between the chosen factors, if present. The Design Expert software generated 20 runs. The optimized conditions obtained were as follows: the agitation rate of 129.8 rpm, incubation temperature at 27.8&degC, and initial pH of 6.06. The optimized conditions tripled the productivity at the range of 980 - 1040 mg/litre/day compared to the initial rate productivity at 310 mg/litre/day. From the quadratic equation,the agitation rate, temperature and the interaction between agitation rate and temperature were found to be significant (p < 0.05). At optimum conditions, the experimental data supported the theoretical estimate.

Effect of Fermented Plant Products on Alkaline-Saline Soil and the Growth of Alfalfa Seedlings

A pot experiment was conducted by putting ameliorants,the products of plants fermented by lactobacillus,and sandy soil into alkaline-saline soil. After such blending,the soil physicochemical properties and the growth index of Alfalfa seedlings were measured in order to explore the influence of the blending on alkaline-saline soil and the growth of alfalfa seedlings. The results showed that soil p H decreased significantly after adding ameliorant; mixing ameliorant and sandy soil into alkaline-saline soil reduced soil evaporation and increased the germination rate of alfalfa seeds and their chlorophyll content as well as the seedling height,root length of alfalfa seedlings,but it had no significant effect on alfalfa seedlings' biomass and leaf number; besides,excessive ameliorant would inhibit the growth of alfalfa seedlings.

On-farm use of legume (<i>Phaseolus calcaratus</i>) and Ruzi grass on rumen fermentation and milk production in lactating dairy cows

The experiment was conducted on 10 small-holder dairy farmers under the administration of Dairy Promotion Organization of Thailand (DPO) in the Northeast region of Thailand. The aim of the research was to investigate the effect of legume (Phaseolus calcaratus, PC) as roughage mixed with Ruzi grass for dairy cows. Fours cows per farm were assigned into 2 groups including Ruzi grass (control) and PC mixed with ruzi grass (at the ratio 50:50), were given ad libitum as a roughage sources. All cows were offered a concentrate with ratio to milk yield of 1:2. The results revealed that roughage source did not affect on ruminal pH and temperature, ammonia nitrogen, blood urea nitrogen, and milk urea nitrogen concentrations. Total volatile fatty acid, acetic acid, propionic acid, and butyric acid proportions, and acetic acid to propionic acid ratio were not significantly different among treatments. Dry matter intake and digestibility of nutrient including dry matter, organic matter, crude protein, neutral detergent fiber and acid detergent fiber were not significantly different among treatments. Moreover, amount of digested dry mater was similar among treatments. However, cows received PC mixed with Ruzi grass tended to be higher on dry matter, organic matter, and crude protein digestibility and dry matter digestible nutrient intake than control group. Milk yield, and 3.5% fat corrected milk were significantly higher (P < 0.05) in cow fed with PC mixed Ruzi grass than those the control group. Milk compositions and feed cost were similar among treatments;in contrast, the income and profit from milk selling were greater in cows fed with PC mixed with Ruzi grass than the control. High quality roughage such as PC mixed with Ruzi grass could be advantages for dairy farming in the Northeast of Thailand.

Production of Lipase Using Cassava Peel and Sunflower Oil in Solid-State Fermentation： Preliminary Study

Full use of residues from industrial processes is a fundamental necessity of contemporary society, since it avoids impacts to the environment by using residues as inputs for other products of high economic and social importance. In this study, lipase production of the crude enzymatic extracts obtained by Aspergillus niger using cassava peel as substrate and sunflower oil as an inductor was investigated. The optimized cultivation temperature and concentration of inductor were determined using the response surface methodology. The two variables studied exercised influence in the production of lipase in the 95% level of confidence. The response surface obtained indicated that the conditions that maximize lipase activity production were 30.5 ~C and initial concentration of sunflower oil was 2.5% （w/w）. Through this analysis, it is evident that extremes in temperature and concentration of inductor tend to decrease lipase production, since low temperatures decrease metabolism and high temperatures may inactivate the lipase. Optimum lipase yield was 59.8 U/g of dry peel which was fermented for 60 h. Lipase production presents a peak of 61.3 U/g, at 72 h of fermentation. However, this value is statistically equal （p 〉 0.05） of the value of lipase activity obtained for 60 h and 84 h of fermentation.

Methodological factors affecting gas and methane production during in vitro rumen fermentation evaluated by meta-analysis approach

Effects of some methodological factors on in vitro measures of gas production（GP, mL/g DM）, CH4production（mL/g DM） and proportion（% CH4 on total GP） were investigated by meta-analysis. These factors were considered：pressure in the GP equipment（0 = constant; 1 = increasing）, incubation time（0 = 24; 1 = ≥ 48 h）, time of rumen fluid collection（0 = before feeding; 1 = after feeding of donor animals）, donor species of rumen fluid（0 = sheep; 1 =bovine）, presence of N in the buffer solution（0 = presence; 1 = absence）, and ratio between amount of buffered rumen fluid and feed sample（BRF/FS; 0 = ≤ 130 mL/g DM; 1 = 130–140 mL/g DM; 2 = ≥ 140 mL/g DM）. The NDF content of feed sample incubated（NDF） was considered as a continuous variable. From an initial database of 105 papers, 58 were discarded because one of the above-mentioned factors was not stated. After discarding 17 papers,the final dataset comprised 30 papers（339 observations）. A preliminary mixed model analysis was carried out on experimental data considering the study as random factor. Variables adjusted for study effect were analyzed using a backward stepwise analysis including the above-mentioned variables. The analysis showed that the extension of incubation time and reduction of NDF increased GP and CH4 values. Values of GP and CH4 also increased when rumen fluid was collected after feeding compared to before feeding（＋26.4 and ＋9.0 mL/g DM, for GP and CH4）,from bovine compared to sheep（＋32.8 and ＋5.2 mL/g DM, for GP and CH4）, and when the buffer solution did not contain N（＋24.7 and ＋6.7 mL/g DM for GP and CH4）. The increase of BRF/FS ratio enhanced GP and CH4production（＋7.7 and ＋3.3 mL/g DM per each class of increase, respectively）. In vitro techniques for measuring GP and CH4 production are mostly used as screening methods, thus a full standardization of such techniques is not feasible. However, a greater harmonization of analytical procedures（i.e., a reduction in the number of available protocols） would be useful to facilitate comparison between results of different experiments.

Macronutrient Composition and Digestibility of Extruded and Fermented Soya Protein Products

The macronutrient composition and in vitro protein digestibility of extruded fermented and unfermented extruded soya protein products （low, medium and high moisture）, raw and fermented soya meal and soya kernel were studied. The protein content （g/100g soya dry weight） ranged from 38.20 to 62.98 with the highest content in the high moisture extruded protein product fermented with 5 mL inoculum of Bacillus natto. Contents of carbohydrates ranged from 14.77 to 29.08 while those of crude fibre, fat and ash were generally low. Fermentation better improved protein digestibility in the raw soya meal and kernel than in the unfermented extruded and extruded fermented products. SDS-PAGE electrophoresis revealed some degradation of the protein sub units of fermented samples.