Volatile Fatty Acid Profile Research Articles

Effects of bacterial cultures, enzymes, and yeast-based feed additive combinations on ruminal fermentation in a dual-flow continuous culture system.

Bacterial cultures, enzymes, and yeast-derived feed additives are often included in commercial dairy rations due to their effects on ruminal fermentation. However, the effects of these additives when fed together are not well understood. The objective of this study was to evaluate the changes in ruminal fermentation when a dairy ration is supplemented with combinations of bacterial probiotics, enzymes and yeast. Our hypotheses were that ruminal fermentation would be altered, indicated through changes in volatile fatty acid profile and nutrient digestibility, with the inclusion of (1) an additive, (2) yeast, and (3) increasing additive doses. Treatments were randomly assigned to 8 fermenters in a replicated 4 × 4 Latin square with four 10 d experimental periods, consisting of 7 d for diet adaptation and 3 d for sample collection. Basal diets contained 52:48 forage:concentrate and fermenters were fed 106 g of dry matter per day divided equally between two feeding times. Treatments were: control (CTRL, without additives); bacterial culture/enzyme blend (EB, 1.7 mg/d); bacterial culture/enzyme blend with a blend of live yeast and yeast culture (EBY, 49.76 mg/d); and a double dose of the EBY treatment (2×, 99.53 mg/d). The bacterial culture/enzyme blend contained five strains of probiotics (Lactobacillus animalis, Propionibacterium freudenreichii, Bacillus lichenformis, Bacillus subtilis, and Enterococcus faecium) and three enzymes (amylase, hemicellulase, and xylanase). On d 8–10, samples were collected for pH, redox, volatile fatty acids, lactate, ammonia N, and digestibility measurements. Statistical analysis was performed using the GLIMMIX procedure of SAS. Repeated measures were used for pH, redox, VFA, NH3-N, and lactate kinetics data. Orthogonal contrasts were used to test the effect of (1) additives, ADD (CTRL vs. EB, EBY, and 2X); (2) yeast, YEAST (EB vs. EBY, and 2X); and (3) dose, DOSE (EBY vs. 2X). No effects (P > 0.05) were observed for pH, redox, NH3-N, acetate, isobutyrate, valerate, total VFA, acetate:propionate, nutrient digestibility or N utilization. Within the 24 h pool, the molar proportion of butyrate increased (P = 0.03) with the inclusion of additives when compared to the control while the molar proportion of propionate tended to decrease (P = 0.07). In conclusion, the inclusion of bacterial cultures, enzymes and yeast in the diet increased butyrate concentration; but did not result in major changes in ruminal fermentation.

Indictable Mitigation of Methane Emission Using Some Organic Acids as Additives Towards a Cleaner Ecosystem

Current study was conducted to figure out the effects of some organic acids as either individually or in combinations at varying levels (Fumaric Acid (Fu), Malic Acid (Ma), Formic Acid (Fo), Fu + Ma, Fu + Fo, Fo + Ma and Fu + Ma + Fo) on volatile fatty acids (VFA) and methane mitigating of some legume forages such as alfalfa (Medicago polymorphia), clover (Trifolium repens) and vetch (Vicia villosa). Graded 100 ml syringes were used in gas production test. Gas volume was measured and sampled at 3, 6, 12, 24, 48, 72 and 96 h of incubation times, headspace produced methane was sampled at 24 h and the VFA profile was assessed at the end of the experiment. Obtained data were analyzed by exploiting SAS package program. Effects of legume forage × organic acid interactions and legume forages on the amounts of gas production determined at different incubation times and the amounts of methane production measured at 24 h of incubation were found significant (p 0.05). Reduction in Acetic Acid percentage was discovered for samples treated with Formic Acid (P < 0.05) but for Butyric Acid samples that treated with Malic Acid showed lower percentage (P < 0.05). As a consequence, the addition of fumaric acid to legume forages was more effective than the other organic acids as either individually or in combinations at varying levels since it was able to increase the amounts of total gas production determined at 24 h and at 96 h, decreased the amount of methane measured at 24 h of incubation. Hence, the fumaric acid could be employed in a nature-friendly and continual way to diminish methane emissions and avoid waste of energy from ruminants thereby improving environmental conditions.

Influence of hydrothermal pretreatment conditions, typology of anaerobic digestion system, and microbial profile in the production of volatile fatty acids from olive mill solid waste

This study aimed to investigate the production of biobased volatile fatty acids (VFAs) from pretreated olive mill solid waste (OMSW). Three hydrothermal pretreatment (HP) conditions (D1: 125 ºC, 53 min; D2: 161 ºC, 62 min; D3: 191 ºC, 83 min) were selected. The pretreated olive mill solid fraction (OMSF), pretreated olive mill liquid fraction (OMLF), and pretreated OMSW were evaluated as potential substrates for acidification in the anaerobic digestion (AD) in liquid (L-AD), semi-solid (Ss-AD), and solid (S-AD) phases. The best acidification efficiency (AE) observed in this study was 65%, for L-AD and HP condition D2 (161 ºC, 62 min). However, the HP condition D2 applied to the Ss-AD provided a VFA concentration of 18218 mg L−1, about 6-fold higher than that observed in the L-AD system. Polyphenols changed the profile of VFAs, increasing the production of longer chain VFAs in the L-AD and S-AD systems. Also, the influence of the typology of the AD system and HP severity on the microbial community was evaluated. Proteobacteria and Firmicutes were the most representative phyla in acidogenic fermentation of OMSW substrates and the genera Enterobacter, Pseudomonas, Achromobacter, Clostridium, Ochrobactrum, and Peptoclostridium played an important role in the pretreated OMSW fermentation and, consequently, in the VFAs production profile.

Effect of ethanol or lactic acid on volatile fatty acid profile and microbial community in short-term sequentially transfers by ruminal fermented with wheat straw in vitro

At present, anaerobic fermentation with waste has become a new utilization direction for the production of VFA, and it has advantages for chemical platforms in replacing non-renewable resources that use petrochemicals as raw materials. In this experiment, the pH value, gas production, VFA production, bacterial and fungal community structure of rumen fermented wheat straw with ethanol or lactic acid in vitro within 8 transfers (3-day interval) were investigated. Ethanol significantly increased the pH value (P < 0.05), while ethanol and lactic acid significantly decreased the gas production (P < 0.05). Ethanol and lactic acid addition increased the production of valeric acid and caproic acid (P < 0.01). The fermentation of ethanol and lactic acid addition showed marked differences in bacterial composition. Clostridium and Ruminococcus genera were the main bacteria producing caporic acid in ethanol culture, while Megasphaera genus was the main bacteria producing valeric acid in lactic acid culture. The relative abundance of Wallemia genus was positively correlated with valeric acid yield (P < 0.05). This result provides reference data that wheat straw co-cultured with ethanol or lactic acid in vitro increases valeric acid and caproic acid production, and bacteria plays more important role than fungi.

Effects of Dietary Supplementation of Black Soldier Fly (Hermetia illucens) Larvae Oil on Broiler Health.

Insects are a potential source of proteins and fats which can be incorporated into diets of broiler chickens. Accordingly, black soldier fly larvae oil (BSFLO) needs to be tested as an appropriate fat source to produce healthy chickens for consumers. Therefore, the objective of the present study was to evaluate the effects of the replacement of soybean oil (SBO) with BSFLO in broiler diets on intestinal health and blood profiles. A total of 210 one-day-old male broilers were randomly allocated to three dietary treatments (10 replicates of seven birds per group): a control diet and two experimental diets in which SBO was replaced with 50% (50 BSFLO) or 100% (100 BSFLO) BSFLO. At the end of the study (35 days), 18 birds (six broilers per treatment) were slaughtered to determine the intestinal morphology, digestibility, and volatile fatty acid (VFA) profile. Blood samples were collected from 24 randomly selected birds (eight broilers per treatment) to determine the blood profiles. BSFLO supplementation positively affected villus height but did not affect digestibility. BSFLO showed no adverse effects on the VFA and blood profiles. In conclusion, the results of this study suggest that SBO can be replaced by BSFLO without any adverse effects on broiler health.

PSVI-14 Effect of Dietary Nitrates and Sulfates on Enteric Methane Mitigation in Finishing Cattle

Abstract A study was conducted to determine the effect of nitrate and sulfate supplementation on cattle performance and methane emissions in finishing diets and to identify the effect of nitrate and sulfate addition on rumen microbiota composition and function. One hundred and thirty one day feeding trial was conducted using 24 head of cattle (initial BW = 918 lb; SD = 79 lb) where the cattle received one of four treatments no supplementation (CON), 2.0% dietary nitrate (NT), 0.54% dietary sulfate (SF) or both (COMBO), with 6 steers per treatment. Performance, volatile fatty acid (VFAs) profile and CH4:CO2 emissions data were analyzed using MIXED procedure of SAS. Rumen samples were collected and analyzed through amplicon sequencing targeting the 16S rDNA gene V4 region. Microbiome richness and composition were analyzed using Qiime2. Microbial genes involved in pathways linked to methanogenesis, nitrate, and sulfate metabolism were identified with metagenomic sequencing. Gene prediction, functional profile and pathway mapping were conducted using KEGG database. In diets with only sulfate or nitrate, diet had no impact on CH4:CO2 emissions, but nitrate and sulfate in combination decreased CH4:CO2. However, a reduction in dry matter intake (DMI) (P &amp;lt; 0.01), average daily gain (ADG) (P = 0.07) and gain:feed (G:F) (P = 0.09) was also recorded. Significant increase in bacterial genera with H2 utilization capability e.g. propionate, lactate forming bacteria e.g. Prevotella, Bacteroides, Megasphaera, Selenomonas, Lactobacillus; nitrate and sulfate reducing bacteria e.g. Selenomonas, Desulfovibrio was observed in COMBO diet. Differential gene abundance in metabolic pathways illustrated decrease of enzymes linked to methanogenesis in COMBO diet. This study provides evidence that methane yield is linked to diet type and differential gene abundance in the cattle rumen microbiome.

Diet supplementation with thyme oil and its main component thymol failed to favorably alter rumen fermentation, improve nutrient utilization, or enhance milk production in dairy cows

Phenolic compounds and essential oils with high content of phenolic compounds have been reported to exert antimicrobial activities in vitro. The objective of this study was to determine the effects of dairy cow diet supplementation with thyme oil and its main component thymol on intake and total-tract apparent digestibility of nutrients, rumen fermentation characteristics, ruminal protozoa, nitrogen excretion, and milk production. For this aim, we used 8 multiparous, ruminally cannulated Holstein cows in a replicated 4 × 4 Latin square design (28 d periods), balanced for residual effects. Cows were fed 1 of the 4 following experimental treatments: total mixed ration (TMR) with no additive (control); TMR + monensin [24 mg/kg of dry matter (DM)]; TMR + thyme oil (50 mg/kg of DM); and TMR + thymol (50 mg/kg of DM). Compared with the control diet, feeding thyme oil or thymol had no effect on DM intake, nutrient total-tract apparent digestibility, total N excretion, ruminal pH, ammonia concentration, total volatile fatty acid (VFA) concentration, or acetate:propionate ratio. Ruminal protozoa density was not modified by thyme oil, but decreased with thymol supplementation. Supplementation with thyme oil or thymol did not affect milk production, milk composition, or efficiency of milk production. Neither thyme oil nor thymol affected efficiency of dietary N use for milk N secretion (N intake/milk N). Supplementation with monensin tended to decrease DM intake (-1.2 kg/d) and milk fat yield. Total-tract apparent digestibility of nutrients did not differ between cows fed monensin and cows fed the control diet. Total VFA concentration was not changed by monensin supplementation compared with control, but adding monensin shifted the VFA profile toward more propionate and less acetate, resulting in a decrease of acetate:propionate ratio. Protozoa density and ammonia concentration were lower in the ruminal content of cows fed monensin compared with that of cows fed the control diet. Total N excretion was not affected by monensin supplementation. Likewise, efficiency of use of dietary N for milk N secretion was unchanged in cows fed monensin. The results of this study contrasted with the claimed in vitro antimicrobial activity of thyme oil and thymol: we observed no positive effects on rumen metabolism (i.e., N and VFA) or milk performance in dairy cows. Under the conditions of this study, including thyme oil or thymol at 50 mg/kg of DM had no benefits for rumen fermentation, nutrient utilization and milk performance in dairy cows.

In Vitro and In Situ Evaluation of Broccoli Wastes as Potential Feed for Ruminants.

Simple SummaryPublic concern about food wastes has increased in recent years. According to the FAO (Food and Agriculture Organization), vegetable food losses happen mainly at cultivation and harvest, but losses at distribution and consumption are also important. The dry matter of some vegetable wastes is rich in protein and fiber and the wastes could be used in ruminant feeding, but information on their nutritive value is needed. Both broccoli florets and stems were studied, and the rumen degradability of diets including increasing amounts of dried broccoli was assessed. Both florets and stems had low dry matter content (<5%), but were rich in protein (>23%) and sugars (>19.9%). Both broccoli fractions were highly degradable in the rumen, with stems showing greater values than florets. In contrast, stems had lower in vitro intestinal digestibility than florets. According to in vitro results, dried broccoli could replace up to 24% of the cereals and high-protein ingredients in a high-cereal concentrate without affecting the rumen fermentation of the diet.The potential of broccoli wastes (florets and stems) as ruminant feed was analyzed using in vitro and in situ techniques. Both stems and florets had high moisture content (90.6 and 86.1%, respectively), but the stems contained (% dry matter) lower levels (p < 0.05) of crude protein (CP; 23.2 vs. 30.8%) and ether extract (2.91 vs. 6.15%) and tended to have greater sugars content (p = 0.071; 33.4 vs. 19.6%) than florets. Stems had greater in vitro dry matter rumen degradability (45.3%; 24 h incubation) and lower in vitro CP intestinal digestibility (82.7%) compared with florets (42.2 and 90.1%, respectively). Rumen degradability of protein was high (<85%) for both fractions. In a second experiment, diets including different proportions of broccoli were formulated and fermented in vitro. The replacement of 24% of conventional feeds (wheat, soybean meal and wheat bran) in a concentrate by dried broccoli increased the amount of organic matter fermented in vitro and the NH3-N concentrations of a mixed diet including 40% of the concentrate. Including dried broccoli in the diet produced only small modifications in the volatile fatty acid profile and did not affect CH4 emission.

Effect of Scrophularia Striata Boiss Extract on in Vitro Gas Production Parameters, Concentration and Volatile Fatty Acids Profile and Hydrolytic Enzyme Activity in Ceca Contents of Male Adults Rabbits

Effect of Scrophularia Striata Boiss Extract on in Vitro Gas Production Parameters, Concentration and Volatile Fatty Acids Profile and Hydrolytic Enzyme Activity in Ceca Contents of Male Adults Rabbits

Effects of Rumen pH on Degradation Kinetics and Fermentation Indices of Corn Silage Ensiled with Antifungal and Carboxylesterase Producing Inoculants

The present study investigated effects of antifungal and carboxylesterase inoculant on rumen fermentation with different rumen pH. Corn silage was treated without inoculant (CON) and with a mixed Lactobacillus brevis 5M2 and L. buchneri 6M1 (MIX). Rumen fluid was collected from two cannulated Hanwoo heifers before morning feeding (high rumen pH at 6.70) and 3 h after feeding (low rumen pH at 6.20). Dried corn silage was incubated in the rumen buffer (rumen fluid + anaerobic culture medium at 1:2 ratio) for 48 h at 39oC. Eight replications for each treatment were used along with two blanks. Both in a high and a low rumen pH, MIX silages presented higher (p<0.05) the immediately degradable fraction, the potentially degradable fraction, total degradable fraction, and total volatile fatty acid (VFA) than those of CON silages. Incubated corn silages in a low rumen pH presented lower (p<0.05) total degradable fraction, ammonia-N, total VFA (p=0.061), and other VFA profiles except acetate and propionate, than those in a high rumen pH. The present study concluded that application of antifungal and carboxylesterase inoculant on corn silage could improve degradation kinetics and fermentation indices in the rumen with high and low pH conditions.

Valorization of sewage sludge in co-digestion with cheese whey to produce volatile fatty acids

The present work explored the production of volatile fatty acids through the anaerobic co-digestion of sewage sludge (SS) and cheese whey (CW). Two batch experiments were conducted to evaluate the effect of the substrate mixing ratio (SS%:CW% of total COD of feedstock) and the initial pH on the acidogenic fermentation of SS with CW at different temperatures. The first batch experiment showed that a decrease of the SS proportion in the co-digestion with CW led to a higher degree of acidification observing a synergistic effect at a SS:CW mixing ratio of 25:75 (SS25:CW75). In the second batch experiment, three temperatures (30 °C, 38 °C and 50 °C) and two initial pH (5.5 and 9) were studied at SS60:CW40 and SS25:CW75 substrate mixing ratios. Maximum degrees of acidification of 56% and 73% were achieved, at 50 °C and initial pH of 5.5, for the SS60:CW40 and SS25:CW75 substrate mixing ratios, respectively. Finally, the performance of a semi-continuous reactor was demonstrated at laboratory scale reactor. Different hydraulic retention times (HRT) (10 and 20 days), pH (uncontrolled, 5.5 and 9) and the effect of a thermal pre-treatment of the SS was studied. The maximum degree of acidification in the lab-scale reactor was 45% at 37 °C, HRT of 20 days and pH of 5.5. Under these conditions, the volatile fatty acids (VFA) profile was dominated by butyric and acetic acids.

Effect of different vegetable wastes on the performance of volatile fatty acids production by anaerobic fermentation

Volatile fatty acids (VFAs) are intermediates of anaerobic fermentation with high value and wide range of usage. VFA production from vegetable wastes (VW) is an effective way to dispose of wastes and recover resources. The organic matter composition of the substrate influences VFA yield and distribution, which is related to the separation and purification of the downstream steps and the application of the product. Hence, potato peels, carrots, celery, and Chinese cabbage were selected to investigate the effect of VW types on the performance of the VFA production in a batch anaerobic fermentation reactor with continuous stirring at 37 °C, total solid (TS) of 4.5%. A VFA yield of 452 mg COD/g VSfeed (chemical oxygen demand (COD); volatile solids (VS)) was achieved from potato peels, which was 40.1%, 21.5%, and 124.9% higher than that of carrots, celery, and Chinese cabbage, respectively. The rapid acidification of carrots caused a sharp decline in pH and led to inhibition of VFA production. The acidification of celery started slowly, and the yield of hexanoic acid increased rapidly in the later stage of fermentation. The VFA yield of Chinese cabbage was inhibited due to the low initial pH, but the ethanol concentration reached 7577.04 mg COD/L. According to the VFA profile, the fermentation of potato peels, carrots, celery, and Chinese cabbage can be classified as propionate-type, butyrate-type, mixed-acid type, and ethanol-acetate type metabolic pathway, respectively. The results of this study suggest that a suitable combination of vegetable waste types is important for selective VFA production.

Effects of high-amylase corn on performance and carcass quality of finishing beef heifers.

Developed initially for use in fuel ethanol production, Enogen Feed Corn (EFC; Syngenta Crop Protection) is genetically modified to express high concentrations of α-amylase in the corn kernel. Experiments were conducted to evaluate processing characteristics of EFC, in vitro digestion, and effects on feedlot performance, carcass characteristics, and liver abscess incidence. Experiment 1 used a randomized complete block design (3 × 3 × 5 factorial) to evaluate starch availability, in situ dry matter disappearance (ISDMD), in vitro gas production (IVGP), and volatile fatty acid (VFA) profiles of in vitro cultures. Grains (EFC or mill-run control [CON]) were flaked to a density of 360 g/L, and mixtures with 0%, 25%, 50%, 75%, or 100% EFC were prepared. Grains were tempered with added moisture (0%, 3%, or 6%) prior to steam conditioning for 15, 30, or 45 min. No two- or three-way interactions were observed. Adding moisture improved starch availability (linear; P < 0.01), and tended to improve ISDMD (linear, P = 0.06). Steam conditioning for 30 min improved starch availability, IVGP, and production of acetate, propionate, butyrate, valerate, and total VFA (P < 0.01) compared with conditioning for 15 or 45 min. Starch availability, ISDMD, IVGP, acetate, propionate, valerate, and total VFA production increased with an increasing proportion of EFC (linear, P < 0.01). Experiment 2 used 700 beef heifers (394 ± 8.5 kg initial body weight [BW]) fed finishing diets with steam-flaked corn as CON or EFC for 136 d. Targeting similar starch availabilities, grains were processed to 360 g/L (CON) and 390 g/L for CON and EFC, respectively. Heifers were blocked by BW, stratified, and then randomly assigned to 28 dirt-surfaced pens (25 animals per pen). Dry matter intakes were similar between treatments (P = 0.78), but cattle fed EFC had greater average daily gain (P < 0.01), improving feed efficiency by 5% (P < 0.01). Hot carcass weight was 6 kg greater for EFC cattle (P <0.01) than CON. No differences were observed for longissimus muscle area (P = 0.89), 12th-rib fat thickness (P = 0.21), or USDA yield grade (P = 0.13). Cattle fed CON had greater marbling scores than EFC (P = 0.04), but this did not affect the USDA quality grade (P > 0.33). Cattle fed EFC had 23% fewer abscessed livers than CON (P = 0.03). High-amylase corn may be used to improve microbial digestion, mill-throughput, and cattle performance, and it may mitigate liver abscesses.

Feeding various forages and live yeast culture on weaned dairy calf intake, growth, nutrient digestibility, and ruminal fermentation

The objective of this study was to determine effects of various forages and live yeast culture on intake, growth, nutrient digestibility, and ruminal fermentation of weaned dairy calves. Holstein calves (n = 45) were randomly assigned to 2 × 3 factorial treatments: live yeast culture or no yeast and alfalfa haylage (AH), corn silage (CS), or grass hay (GH). Calves were weaned at 6 wk of age, housed individually, and studied from 7 to 16 wk of age. Rations, consisting of an 18% crude protein texturized grower (yeast or no yeast) and assigned forage, were offered as separate components until 9 wk of age. After 9 wk, diets were offered as a total mixed ration (TMR). Concentrate intake was capped at 2.25 kg of dry matter (DM)/d, and forage was offered ad libitum. The TMR contained equal forage neutral detergent fiber (8 ± 0.5%) on a DM basis for each basal diet. Calves were fed TMR to limit concentrate intake, and additional forage was offered ad libitum after 8 h if the entire TMR allotment was consumed. Total fecal collection (12 calves) was conducted for 4 d at 11 and 15 wk of age. Feeds and feces were evaluated for DM, neutral detergent fiber, acid detergent fiber, and starch to calculate digestibility. On the last day of fecal collection, rumen samples were collected to evaluate pH and volatile fatty acid (VFA) profile. Metabolizable energy and DM intake was least for calves consuming GH compared with other forages. Forage intake (% of DM intake) increased as calves aged (AH = 20 to 44.4%, CS = 24.5 to 37.6%, GH = 11.3 to 32.3% at 10 and 16 wk of age, respectively). Calves on CS had the greatest average daily gain and empty body weight gain, and calves on GH had the least. Calves on GH tended to have the lowest final body weight. There were no differences in structural growth. Digestibility of DM decreased with age. Fiber digestibility was least for calves on CS, and starch digestibility was least for calves on AH. Mean and minimum rumen pH increased with age. Forage offered changed VFA profile and there was an interaction between yeast and forage on VFA profile. These results indicated that recently weaned calves perform well on AH, CS, or GH and have minimal benefit from yeast supplementation. Feeding GH reduced weight gain, but all calves achieved a level of gain to meet growth goals for breeding and freshening. Furthermore, the ability to consume large portions of the ration as forage allows for more economical diets to be fed.

Increasing grass hay inclusion level on weaned dairy calf growth, intake, digestibility, and ruminal fermentation

The objective was to determine effects of increasing grass hay (GH) inclusion level on weaned dairy calf growth, intake, digestibility, and ruminal fermentation. Holstein calves (n = 45) were randomly assigned to 1 of 3 total mixed rations with increasing GH [10, 17.5, or 25% on a dry matter (DM) basis; LGH, MGH, or HGH, respectively]. Calves were weaned at 6 wk of age, housed individually, and studied from 7 to 16 wk of age. Rations, consisting of texturized calf starter (20% crude protein) and coarsely chopped GH, were offered ad libitum as separate components from 7 to 9 wk of age. After 9 wk, feed was offered as a total mixed ration containing the assigned level of GH and fed according to the clean bunk feeding strategy as a means of limiting refusals. Initial 9-wk body weight was 81.6 ± 9 kg (mean ± standard deviation). Intake and growth were measured weekly. Blood samples were collected at 9, 10, 12, 14, and 16 wk of age for analysis of plasma glucose and β-hydroxybutyrate. Total fecal collection (12 calves; 4 per treatment) was conducted at 11 and 15 wk of age for 4 d consecutively. Rumen samples were collected over the final 24 h of each fecal collection period to evaluate pH and volatile fatty acid profile. Feeds and feces were evaluated for DM, neutral detergent fiber, acid detergent fiber, and starch to estimate total-tract digestibility. Intake and weight gain were analyzed from 7 to 9 wk and 9 to 16 wk, representing pretreatment and treatment periods. No differences were observed between treatments from 7 to 9 wk. However, differences were found from 9 to 16 wk. Final body weight, average daily gain, DM intake, and metabolizable energy intake all decreased with increased GH. However, skeletal frame measurements did not vary between treatments. Plasma β-hydroxybutyrate tended to decrease with increased GH. No differences were observed in DM or starch digestibility, but neutral detergent fiber and acid detergent fiber digestibility increased with increased GH. Mean rumen pH and total volatile fatty acid did not change with increasing GH inclusion; however, there was an interaction with time indicating that ruminal fermentation patterns throughout the day were different for calves offered MGH and HGH versus those offered LGH. These results indicate that feeding levels of GH >10% reduce growth and intake before 16 wk and alter ruminal fermentation patterns.

Effect of Sulfur and Urea Fortification of Fresh Cassava Root in Fermented Total Mixed Ration on the Improvement Milk Quality of Tropical Lactating Cows.

The aim of the present research was to determine the influence of sulfur and urea combined with fresh cassava root in fermented total mixed ration (FTMR) on digestibility, fermentation in the rumen, blood metabolite, milk yield, and milk quality in tropical lactating dairy cows. Four mid-lactation Thai Holstein–Friesian crossbred cows were studied. Pre-experiment milk yield was 12.7 ± 0.30 kg/day, and the body weight was 495 ± 40.0 kg. Animals were evaluated in a 2 × 2 factorial in a 4 × 4 Latin square design to receive diets followed by: factor A, which was a dose of sulfur inclusion at 1.0% and 2.0%, and factor B, which was level of urea inclusion at 1.25% and 2.5% DM in FTMR. The hydrogen cyanide (HCN) concentrations reduced 99.3% to 99.4% compared with fresh cassava root when FTMR was supplemented with 1.0% and 2.0% sulfur, respectively. Intake of crude protein was increased based on urea level addition (p < 0.05). Blood thiocyanate concentration was increased by 21.6% when sulfur was supplemented at 2.0% compared to 1.0% (p < 0.05). There was no difference in protozoal concentration, whereas bacterial populations at 4 h after feeding were significantly greater by 6.1% with the FTMR supplemented with 2.0% sulfur and 2.5% urea (p < 0.01). Allantoin concentrations, excretion, absorption, and microbial crude protein showed significant interactions between sulfur levels and urea levels in cows fed diets supplemented with 2.0% sulfur and 2.5% urea (p < 0.05). The molar ratios of the volatile fatty acid (VFA) profile were affected by dietary FTMR (p < 0.01). Furthermore, propionic acid increased by 4.6% when diets were supplemented by 2.5% sulfur (p < 0.01). Milk fat and total solids increased when feed was supplemented with 2.0% sulfur and 2.5% urea (p < 0.05). The diets supplemented with 2.0% sulfur levels resulted in greater concentrations of milk thiocyanate (p < 0.05). The somatic cell count was significantly reduced throughout the experiment with increasing sulfur supplementation (p < 0.05). Animals fed diets supplemented with 2.0% sulfur exhibited a decreased somatic cell count by 18.3% compared with those fed diets supplemented with 1.0% sulfur. Thus, inclusion of 2.0% sulfur with 2.5% urea in FTMR containing fresh cassava root improved digestibility, ruminal fermentation, microbial crude protein synthesis, and milk qualities in dairy cows.

Effects of conditioner retention time during pelleting of starter feed on nutrient digestibility, ruminal fermentation, blood metabolites, and performance of Holstein female dairy calves

This study evaluated the effects of conditioner retention time during the pelleting process of starter feed on intake, nutrient digestibility, ruminal fermentation, blood metabolites, and growth performance of dairy calves. A total of 30 Holstein female dairy calves [40 ± 1.93 kg of body weight (BW)] were randomly assigned to 1 of 3 treatments: (1) pelleted starter conditioned for 0 min (CON), (2) pelleted starter conditioned for 2 min, and (3) pelleted starter conditioned for 4 min. Three pelleted starter feeds had similar nutritional composition, and the starters were blended with 3% chopped wheat straw and fed to individually housed calves from d 3 to 70 of age. All calves were fed 4 L/d of pasteurized whole milk twice daily at 0800 and 1600 h from d 3 to 50 of calf age, followed by 2 L/d of morning feeding from 51 to 56 d of age. All calves were weaned on d 56 of age and remained in the study until d 70 of age. With the increase of conditioner retention time during pellet processing for 0, 2, and 4 min, the gelatinized starch content of pelleted starter feed linearly increased from 14, 30, and 45%, respectively. Additionally, the pellet durability and hardness also linearly increased with increasing conditioner retention time during pelleting. Feeding pelleted feed prepared using different conditioner retention time did not affect feed dry matter intake, metabolizable energy intake, weaning BW, final BW, or feed efficiency during the study. We observed no differences in the total-tract apparent digestibility of organic matter, neutral detergent fiber, and crude protein around weaning (d 49 to 56 of age) and after weaning (d 63 to 70 of calf cage); however, the digestibility of dry matter and starch after weaning was increased with increasing conditioner retention time during pelleting of starter feed. No difference was found in overall average daily gain (ADG) or growth rates of hip height, withers height, and heart girth. Ruminal volatile fatty acid profile was not affected by pelleting under different conditioner retention times. The ruminal ammonia concentration tended to be lower for calves fed the 4-min diet compared with those fed the CON diet during the postweaning period. The postweaning (d 57-70 of age) ADG was greater for calves fed the 4-min diet compared with those fed the CON diet. In conclusion, the conditioning time during the pelleting process of starter feed increased the gelatinization of starch, durability, and hardness of the pellets but did not influence feed intake, feed efficiency, and skeletal growth during the first 70 d of age. Increasing conditioning time during the pelleting process improved postweaning ADG; however, the final BW of calves was similar among treatments.

Volatile fatty acids production from biowaste at mechanical-biological treatment plants: Focusing on fermentation temperature

The impact of temperature (20, 35, 45, 55, 70 °C) on volatile fatty acid (VFA) production from biowaste collected at a mechanical–biological treatment plant was analysed. Additionally, relevant streams of the treatment plant were characterised to assess seasonality effects and conceive the integration of a fermentation unit. Batch fermentation tests at 35 °C showed the highest VFA yields (0.49–0.59 gCODVFA/gVS). The VFA yield at 35 °C was 2%, 6%, 10% and 14% higher than at 55, 45, 20 and 70 °C, respectively. The VFA profile was not affected by the fermentation temperature nor seasonality and was dominated by acetic, propionic and butyric acid (75–86% CODVFA). The concentration of non-VFA soluble COD and ammoniacal nitrogen in the fermentation liquor increased with temperature. The fermentation unit in the treatment plant was conceived after the pulper and hydrocyclones and before the anaerobic digester, while the fermenter temperature depends on the VFA application.

Evaluation of the volatile composition and fatty acid profile of seven Antarctic macroalgae

Fatty acids (FAs) and volatile organic compounds (VOCs) are among bioactive substances produced by macroalgae, which have important reported biological activities. The aim of this work was to determine the diversity of FAs and VOCs in brown, green, and red Antarctic macroalgae. Results showed that seaweeds contained 13 to 25 FAs with a predominance of palmitic, oleic, linoleic, and eicosapentaenoic acids. Concerning VOCs, 28 to 55 distinct compounds could be detected, distributed among aldehydes, hydrocarbons, furan derivatives, and ketones, for instance. Generally, hexanal (5.83%–25.51%), heptadecane (0.92%–49.84%) and 2-pentylfuran (3.02%–12.57%) were found in considerable amounts in the analyzed specimens. It is worth noting that, to the best of our knowledge, this was the first time that Antarctic macroalgae had their VOCs elucidated. Therefore, Antarctic seaweeds were composed of several VOCs and FAs which could assist in the elucidation of secondary metabolites from these organisms.

Microbiome Diversity and Differential Abundances Associated with Gastrointestinal Symptoms, BMI, Immune Markers, and Fecal Short Chain Volatile Fatty Acid Profiles

Abstract Objectives The gut microbiota and its metabolites – namely short chain volatile fatty acids (SCVFAs) – interact with the digestive, immune, and nervous systems. States of microbiome dysbiosis are highly associated with obesity and GI symptoms, and profiles of SCVFAs, which serve functions as fuel sources and signaling molecules, mimic this dysbiotic state. This study aimed to further our understanding of associations between bacterial diversity and GI symptoms, BMI, immune markers, and SCVFAs and to identify bacteria differentially abundant with changes to the previously mentioned variables. Methods Data (measures of GI distress, BMI, immunoglobulins, fecal proximate analysis, SCVFAs, and 16s RNA sequences) was extracted from a study containing non-celiac gluten-sensitive and control participants. QIIME2 was used to process 16s RNA data, analyze quantitative, qualitative, phylogenetic quantitative, and phylogenetic qualitative measures of alpha and beta diversity and to perform an analysis of composition of microbes (ANCOM) for differential abundances data. Results Many significant differences were seen, namely in multiple measures of alpha diversity for IgG4 (P &amp;lt; 0.018), propionate (P &amp;lt; 0.014), caproate (P &amp;lt; 0.003), heartburn (P &amp;lt; 0.004), urgent need to defecate (P &amp;lt; 0.027), and feelings of incomplete evacuation (P &amp;lt; 0.024). Statistical significance was seen in multiple measures of beta diversity between normal and overweight (P &amp;lt; 0.01), normal and obese (P &amp;lt; 0.005), and overweight and obese BMI (P &amp;lt; 0.016), IgG4 (P &amp;lt; 0.033), propionate (P &amp;lt; 0.001), increased gas (P &amp;lt; 0.024), and urgent need for defecation (P &amp;lt; 0.026). The ANCOM identified multiple species of bacteria differentially abundant with changes to variables. Conclusions Findings suggest differences in both alpha and beta diversity with various GI symptoms, SCVFAs, and BMI. This research supports plans to apply analysis to larger sample sizes to train machine learning classifiers to identify important features of microbial profiles associated with certain SCVFA and markers of health. Funding Sources ETSU (CCRHS, Deans's Research Enhancement Award and CPH, Health Sciences Funding, Honors College Summer Research Fellowship) and Shield Nutraceuticals, LLC.