Crude glycerin changes ruminal parameters, in vitro greenhouse gas profile, and bacterial fractions of beef cattle

Physicochemical and microbiological parameters of rumen fluid of lactating goats fed diets containing crude glycerin from waste frying oil used in biodiesel production

Crude glycerin from the biodiesel industry is a alternative energy source used to replace part of the energy components of the diet, since the nutritional value of glycerol makes it suitable for use in ruminant diets. The objective was to analyze the effects including crude glycerin (CG) derived from the production of biodiesel from residual frying oil, in diets of lactating goats on the physicochemical and microbiological parameters of rumen fluid. Eight 2-year-old goats weighting approximately 42.06 ± 3.5 kg of body weight (BW) were kept in individual stalls, receiving diets containing 0, 7, 14 and 21% of CG (% DM). The experiment was carried out according to a double 4 × 4 Latin square and lasted for 80 days. Orthogonal contrasts were tested to determine linear and quadratic effects, as well as the effects of 0% CG in the diet in comparison to the other treatments. There was a linear decreasing effect on DM intake (P = 0.001) and neutral detergent fiber (P = 0.0001), as well as a quadratic effect (P = 0.0002) on ether extract (EE) intake with increasing level of CG in the diet. Including CG affected motility and density of the protozoa (P = 0.0001). Treatments had no effect on pH, N-NH3 concentration and percentage of protozoa in the rumen liquid. There was increasing linear effect on sedimentation and flotation time (P = 0.001). Therefore, including 14 and 21% CG in the diet as a source of glycerol decreased nutrient intake and altered the ruminal microbiota, but pH and N-NH3 were not affected. Thus, to avoid impairment to the physicochemical and microbiological parameters of the rumen liquid of goats, the inclusion of CG should not exceed 7% DM.

Effects of Different Dietary Carbohydrate Sources on the Meat Quality and Flavor Substances of Xiangxi Yellow Cattle

This study investigated the dietary supplementation of starches with different carbohydrate sources on the proximate composition, meat quality, flavor substances, and volatile flavor substances in the meat of Chinese Xiangxi yellow cattle. A total of 21 Chinese Xiangxi yellow steers (20 ± 0.5 months, 310 kg ± 5.85 kg) were randomly divided into three groups (control, corn, and barley groups), with seven steers per group. The control steers received a conventional diet (coarse forage type: whole silage corn at the end of the dough stage as the main source), the corn group received a diet with corn as the main carbohydrate source, and the barley group received a diet with barley as the main carbohydrate source. The experiment lasted for 300 d. and the means of the final weights in the control, corn, and barley groups were 290 kg, 359 kg, and 345 kg. The diets were isonitrogenous. The corn and barley groups reduced the moisture (p = 0.04) and improved the intramuscular fat content of the meat (p = 0.002). They also improved meat color (a*) (p = 0.01) and reduced cooking loss (p = 0.08), shear force (p = 0.002), and water loss (p = 0.001). There was no significant difference in the 5′-nucleotide content (p > 0.05), the equivalent umami concentration (EUC) (p = 0.88), and taste activity value (TAV) (p > 0.05) among the three groups. The 5′-IMP (umami) content was the highest in the 5′-nucleotide and its TAV > 1. The corn and barley groups improved the content of tasty amino acids (tAA, p < 0.001). The corn group had a higher content of sweet amino acids (SAA, p < 0.001) and total amino acids (TAA, p = 0.003). Corn and barley improved the levels of MUFA (p < 0.001), PUFA (p = 0.002), n-3 PUFA (p = 0.005), and n-6 PUFA (p = 0.020). The levels of alcohols, hydrocarbons, and aldehydes in the corn group were higher than in the barley and control groups (p < 0.001). The esters content in the corn group was higher than in the barley and control groups (p = 0.050). In conclusion, feeding corn or barley as a carbohydrate source can improve the nutrient content and taste. Feeding corn as a carbohydrate source can improve the content of free amino acids (Cys, Glu, Gly, Thr, Leu, Trp, Gln, Asn, and Asp), fatty acids (saturated fatty acid, monounsaturated fatty acid, polyunsaturated fatty acid, n-3PUFA, n-6PUFA, and total fatty acid), and volatile flavor substances (alcohols, aldehydes, acids, and hydrocarbons) to improve the flavor and meat quality.

Combinations of by-products from biodiesel production included in the supplement for finishing heifers on deferred pastures

We hypothesized that by-products from biodiesel production like crambe meal (Crambe abyssinica) totally replace soybean meal (Glycine max) and crude glycerin could partially replace corn (Zea mays). Our aim was to evaluate different supplements with combinations of crambe meal and crude glycerin replacing soybean meal or corn on performance and carcass traits of finishing heifers. Sixty Nellore heifers 18 months old were used, and 298.96 ± 21.99 kg of body weight allotted in Brachiaria brizantha pastures. All heifers were distributed in a randomized complete block design, with four treatments being the following supplements: corn + soybean meal (CS), corn + crambe meal (CCr), corn + soybean meal + crude glycerin (CSG), corn + crambe meal + crude glycerin + (CCrG). The animals were distributed in four paddocks of 13 hectares each, in a continuous grazing system. We evaluated pasture characteristics, intake, performance, carcass traits, characteristics, and centesimal composition of Longissimus thoracis muscle. There was an effect (P < 0.05) of inclusion of crambe meal on the performance of the animals for slaughter weight and daily gain. The supplement containing corn + soybean meal (CS) presented better conversion rates and food efficiency. There was an effect of inclusion of crambe meal and crude glycerin on the centesimal composition of Longissimus thoracis muscle. The use of crambe meal and crude glycerin as alternative sources from the agro-industry of biodiesel in concentrate supplement for finishing heifers in pastures can promote positive effects related to productive performance and carcass characteristics.

Crude glycerin in the supplementation of crossbred heifers in tropical pastures

Crude glycerin (CG) is a biodiesel byproduct that has been tested as an alternative feed additive for use in beef production. After being absorbed, it is used in the liver to produce glucose, an important precursor of intramuscular fat in ruminants. This study aimed to evaluate the effect of CG (439 g/kg glycerol) on the performance and meat quality of crossbred heifers finished in Urochloa brizantha cv. Marandu. Thirty-six heifers with an initial BW of 301.5 ± 23.02 kg were used. They were supplemented for 154 days with the following levels of CG: mineral mixture (without CG), 33.3, 66.6 and 99.9 g/kg CG in the DM of the supplement. Supplement or pasture DM intakes, slaughter BW and carcass traits were not influenced (P > 0.05) by increasing levels of CG. The total fat content of the meat, the vaccenic (18:1 n-7t) and conjugated linoleic acid (18:2 c9-t11) increased with the addition of CG in the diet (P < 0.05). Crude glycerin can be included up to 99.9 g/kg of the total diet without changing the performance of crossbred heifers finished in the tropical pasture.

Estimation of ruminal outflow in buffaloes fed diets with different energy and protein sources by use of reticular and omasal sampling

This study aimed to evaluate the effects of different traditional or alternative energy and protein sources, associated or not, on feeding behavior, ruminal kinetics, and post-ruminal flow of nutrients. Besides, it was assessed diets' effects on different sites (reticulum and omasum) of buffaloes. Four ruminally cannulated male Murrah buffaloes (average initial weight of 637 ± 66.37 kg) were randomly distributed in a 4 × 4 Latin square design. Treatments were arranged as 2 × 2 factorial arrangement. The first factor evaluated was the inclusion of energy sources (ground corn and crude glycerin), and the second factor was the inclusion of protein sources (soybean meal and cottonseed cake). Buffaloes fed cottonseed cake had a higher content of neutral detergent fiber (NDF) and potentially digestible detergent fiber (pdNDF) in the rumen environment than buffaloes fed soybean meal. There was a sampling site effect on rumen digestion rates of pdNDF, passage rates of indigestible neutral detergent fiber (iNDF), and pdNDF, and flow of iNDF. In this study, omasal collections were more representative. Total replacement of ground corn by crude glycerin promoted less NDF ruminal digestibility, and care should be taken to include this energy source. The cottonseed cake does not cause a difference in rumen dynamics and can totally replace soybean meal in feedlot buffaloes' diet.

Feeding behavior of feedlot lambs fed diets with different energy and protein sources

This study aimed to evaluate the effect of the replacement of ground corn by crude glycerin and soybean meal by cottonseed cake, in association or not, on feedlot lambs' feeding behavior. Thirty-two non-castrated crossbred ½ Dorper ½ Santa Inês lambs, with an average body weight of 18.52 ± 3.24 kg (mean ± standard deviation), were distributed in a completely randomized design, into four treatments and eight replicates per treatment, in a 2 × 2 factorial scheme. Four experimental diets were tested with different sources or combinations of energy and protein ingredients in the concentrate, respectively: (1) ground corn + soybean meal; (2) ground corn and cottonseed cake; (3) crude glycerin and soybean meal; and (4) crude glycerin and cottonseed cake. The glycerin decreased dry matter (DM) and neutral detergent fiber (NDF) (P < 0.001) intakes, whereas it increased times spent in feeding (P = 0.009; from 21.8 to 28.6), rumination (P = 0.006; from 56.2 to 67.2), and chewing (P < 0.001; from 79.4 to 97.2), in minutes/100 g of DM. Feeding efficiencies of DM (P = 0.003) and NDF (P = 0.008) were decreased by the diets. Protein sources increased (P = 0.018) the times spent in chewing and per period in rumination (P = 0.014). Cottonseed cake, as a protein source, up to a 112 g/kg DM level, can totally replace soybean meal in diets for feedlot lambs without effects on the intake, behavioral activities, and feeding efficiencies. In contrast, the crude glycerin energy source is not adequate to replace ground corn in lambs' diets.

Glycerine as a feed supplement for beef and dairy cattle: A meta-analysis on performance, rumen fermentation, blood metabolites and product characteristics

This study aimed to comprehensively evaluate the effects of glycerine supplementation at various concentrations on performance, rumen fermentation, blood metabolites and product characteristics of beef and dairy cattle in vivo by using a quantitative meta-analysis approach. Meta-analysis was performed by integrating a total of 52 studies from 39 articles and 182 treatments into a database. Data were constructed into an intact database and did not distinguish between beef and dairy cattle, except for the parameters of production performance and product characteristics. Data summarized were analysed by using a statistical meta-analysis that employed a fixed effect of glycerine supplementation level and a random effect of various studies for both beef and dairy cattle. Significance of an effect was stated at the probability level of p < .05, and p < .1 was considered as a tendency of significant. Results revealed that there was a linear decrease on dry matter intake (p < .01) and daily gain (p < .05) of beef cattle with the increasing levels of glycerine supplementation. Glycerine supplementation did not decrease milk production of lactating dairy cows. Molar proportion of acetate in the rumen was decreased (p < .001), whereas propionate and butyrate proportions were increased (both at p < .001) by glycerine supplementation. Generally, glycerine did not change nutrient digestibility except that it reduced fibre digestibility (p < .001). Glycerine supplementation linearly lowered triglyceride and NEFA concentrations (both at p < .05) in the blood serum, but not other blood metabolites. Glycerine tended to linearly increase (p < .1) carcass percentage in beef cattle. Increasing dietary glycerine levels decreased milk fat (p < .01) but elevated milk protein (p < .001). Glycerine tended to increase milk lactose (p < .1) by following a quadratic pattern. The proportion of MUFA was increased quadratically by glycerine supplementation (p < .05), whereas glycerine tended to decrease SFA by following a quadratic pattern (p < .1).

Metabolism, Ketosis Treatment and Milk Production after Using Glycerol in Dairy Cows: A Review

Simple Summary

Glycerol, as well as being an attractive feed ingredient for cattle, is also a by-product of a wide range of industrial applications. Glycerol has potential value in farming since it improves metabolism, feed efficiency, and can alleviate the symptoms of ketosis. Data indicate that glycerol can be a suitable partial grain replacement in the diet of cows during the transition period and at the beginning of lactation. The impact on milk yield is not significant, but glycerol mostly decreases milk fat content. The inclusion of dietary glycerol in the ration of dairy cows has an affect on ruminal fermentation patterns. Glycerol is rapidly fermented in the rumen into propionate, and it is metabolized to glucose in the liver through the process of glycogenolysis. Additionally, glycerol administration to ruminants can reduce greenhouse gas emissions. The purpose of this review is to highlight the potential benefits and drawbacks related to the use of glycerol in cattle.

Abstract

The aim of this paper is to review and systematize the current state of knowledge on glycol metabolism in cattle. Glycerol, derived from biodiesel production, must be purified in order to be a useful product for feeding livestock. The use of glycerol in the feeding of ruminants can be justified for several reasons: (i) it is a source of energy in the ration, (ii) it is a glucogenic precursor, and (iii) it may have an effect on milk composition. The high energy value of glycerol provides the opportunity to use this raw material as a partial grain substitute in cattle feed rations. Dietary supplementation of glycerol is associated with increased propionate, butyrate, valerate, and isovalerate concentrations in the rumen. Glycerol can be used at up to 10%–15% of the dietary dry matter (DM) and is well-established as a treatment for ketosis in cows. Glycerol increases plasma glucose and may reduce non-esterified fatty acids and β-hydroxybutyrate levels. The use of glycerol does not have a clear effect on DM intake, milk yield, or milk composition. However, some authors have reported an increase in milk yield after glycerol supplementation associated with decreased milk fat concentration. It is also possible that the concentration in the milk of odd-chain fatty acids and cis-9, trans-11 conjugated linoleic acid may increase after glycerol application.

Evaluation of Lactobacillus plantarum MTD1 and waste molasses as fermentation modifier to increase silage quality and reduce ruminal greenhouse gas emissions of rice straw

Lactobacillus plantarum and molasses have been shown to function as fermentation modifiers in both silage and rumen fermentation. This study aimed to evaluate the effects of L. plantarum MTD1, a commercial probiotic, when co-administered with waste molasses (WM), on the silage quality, rumen volatile fatty acids and greenhouse gas (GHG) production of rice straw. Rice straw was ensiled with no additive (Control), 10⁶ cfu/g L. plantarum (L), L + 2%WM, L + 3%WM and L + 4%WM for 3, 6, 9, 15, 30 and 60 days. The rumen volatile fatty acids and gas production kinetics were determined using in vitro incubation technology. All additives, especially L + 4%WM, improved the silage quality of rice straw, indicated by higher lactic acid and nonstructural carbohydrate content, lower pH, butyric acid and ammonia nitrogen content (P < 0.05). A simple linear regression showed that the ruminal propionic concentration increased (linear, P < 0.0001) and the ratio of acetic to propionic acid decreased (linear, P = 0.0002) as a function of WM dose. The 60-day ensilage could decrease ruminal total gas production by 13.51-31.29% as compared to the untreated rice straw. Wherein L had no effect on the mitigation of CH₄ but decreased the CO₂ production, and further WM inclusion decreased the CH₄ production with a dose effect. If the better silage quality and lower ruminal GHG production observed in the study are confirmed in practice, applying L + 4%WM may provide an insight for straw waste management while reducing pollution input into the atmosphere system. This in vitro study can be valuable for screening and informing on the suitability of these fermentation modifiers for further evaluation in vivo.

Elevated concentrations of crude glycerin in diets for beef cattle: feedlot performance, carcass traits, and ruminal metabolism1

Three experiments were conducted to evaluate the inclusion of crude glycerin (CG) in diets for beef cattle. In Exp. 1, 4 ruminally cannulated steers were fed diets with 0 or 15% CG (DM basis), to evaluate DM disappearance, VFA profiles, and gas production. There was a tendency for an interaction (P = 0.06) between diet fed to donor animals and substrate fed to in vitro system, and digestion was increased when CG was added to cultures with ruminal fluid from CG-fed animals. Total VFA were unaffected by diets or by substrate incubated. The CG increased production of propionate, butyrate, and valerate (P < 0.01) while the gas production was unaffected (P = 0.16). In Exp. 2, 24 crossbred heifers (334.4 ± 0.9 kg BW) were fed the same diets as Exp. 1, for 35 d. Fecal grab samples were collected 3 times daily on day 7, 21, and 35, to evaluate total tract digestibilities of DM, OM, and NDF. The CG improved digestibility of diet OM (P = 0.04), and DM followed a similar trend (P = 0.06), while the NDF digestibility was unaffected (P = 0.29). In Exp. 3, crossbred heifers (n = 374; 375.8 ± 36.1 kg BW) were used to evaluate feedlot performance and carcass traits when fed diets with 0, 7.5, or 15% CG, with or without added 0.3% salt. Heifers were assigned to 25 pens and were harvested on day 125. Removing salt from CG-based diets did not impact performance (P = 0.50). The CG did not influence average daily gain (P = 0.27), but decreased DM intake (P = 0.003), USDA Yield Grade (P = 0.01), and improved feed efficiency (P = 0.03), while tended to decrease USDA prime carcasses (P = 0.10). Carcass weight (P = 0.24), Longissimus muscle area (P = 0.63), and kidney, pelvic, heart fat (P = 0.59) were unaffected by CG. Twelfth-rib fat was less for heifers fed 15% CG without salt compared with the other treatments (P = 0.005), while marbling was less for heifers fed CG diets compared with the control-fed animals (linear, P = 0.004; quadratic, P = 0.02). In conclusion, GC can replace dry-rolled corn in diets for beef heifers when fed at 15% of diet DM, improving OM digestion, increasing ruminal propionate and butyrate without affecting greenhouse gas emissions. Feeding up to 15% CG improves feed efficiency but depresses marbling and tends to decrease Quality Grade. Removing supplemental salt from CG-diets has no impact on performance or carcass traits.

In vitro fermentation of Pennisetum clandestinum Hochst. Ex Chiov increased methane production with ruminal fluid adapted to crude glycerol

The aim of this trial was to determine the effect of ruminal fluid adapted to crude glycerol supplementation on in vitro methane and fermentation parameters of the forage Pennisetum clandestinum Hochst. Ex Chiov (Kikuyu forage) of 35 (D35) and 45 days (D45) of regrowth. Four non-lactating cannulated Holstein cows with 600 ± 33 kg LW, under a randomized Latin square design (4 animals × 4 periods), were used to obtain ruminal fluid after adaptation for 13 days within each period to supplementation in the rumen with crude glycerol (GL): 0 (GL0), 500 (GL1), 1000 (GL2), and 1500 g/cow/day (GL3). All the variables were analyzed under a 4 × 2 split-plot arrangement, where the ruminal fluid adaptation to supplementation with GL and its interaction with the incubated diets (GL× D) were analyzed. Ruminal pH values and in vitro apparent degradability of the dry matter (DMd) and organic matter (OMd) were not affected, with a decrease in the concentrations of NH₃-N and acetate by the ruminal fluid adapted to crude glycerol. The concentrations of propionate and butyrate increased, without affecting the total concentration of VFA in the ruminal fluid. The in vitro methane production increased with forage D35 and GL1, GL2, GL3. The in vitro methane production with the D45 forage increased with the ruminal fluid adapted to GL2 and GL3. The ruminal fluid adapted to crude glycerol supplementation increased in vitro methane production when incubating the forage Kikuyu.

Effect of adding crude glycerine to diets with feed additives on the feed intake, ruminal degradability, volatile fatty acid concentrations and in vitro gas production of feedlot Nellore cattle

The effects of adding crude glycerine with sodium monensin or essential oils to beef cattle diets on the intake, degradability of DM and nutrients, rumen concentration of volatile fatty acids (VFA) and in vitro gas production were evaluated. Five ruminally cannulated Nellore steers were randomly assigned to a 5 × 5 Latin square design. The treatments were as follows: CONT, without crude glycerine and additives; EO, with essential oils and without crude glycerine; MON, with sodium monensin and without crude glycerine; EOG, with essential oils and crude glycerine; MONG, with sodium monensin and crude glycerine. Treatments with essential oil and sodium monensin increased the NDF and STC intake and the DM degradability. When crude glycerine was combined with either sodium monensin or essential oil, there was a reduction in DM, NDF and STC intake and an increase in DM and CP degradability of the diets. The adding crude glycerine to essential oil diets reduced the CH₄ production. Sodium monensin treatments reduced DM and NDF intake and the production of total gas, CH₄ , total VFA and acetic acid concentration. In conclusion, the adding crude glycerine (200 g/kg DM) with either sodium monensin (0.03 g/kg DM) or essential oil (0.5 g/kg DM) can be utilized in diets for Nellore cattle without causing detrimental effects on feed intake and improving the DM degradability.

Evaluation of glycerol encapsulated with alginate and alginate-chitosan polymers in gut environment and its resistance to rumen microbial degradation

OBJECTIVE

To determine the effect of gut pH and rumen microbial fermentation on glycerol encapsulated in alginate and alginate-chitosan polymers.

METHODS

Glycerol was encapsulated at 2.5%, 5%, 7.5%, or 10% (w/w) with sodium alginate (A) and alginate-chitosan (AC) polymers. Surface morphology and chemical modifications of the beads were evaluated using scanning electron microscopy and Fourier transform infrared (FTIR) spectra. Encapsulation efficiency was determined at the 5% glycerol inclusion level in two experiments. In experiment 1, 0.5 g of alginate-glycerol (AG) and alginate-chitosan glycerol (ACG) beads were incubated for 2 h at 39°C in pH 2 buffer followed by 24 h in pH 8 buffer to simulate gastric and intestinal conditions, respectively. In experiment 2, 0.5 g of AG and ACG beads were incubated in pH 6 buffer at 39°C for 8 h to simulate rumen conditions. All incubations were replicated four times. Free glycerol content was determined using a spectrophotometer and used to assess loading capacity and encapsulation efficiency. An in vitro experiment with mixed cultures of rumen microbes was conducted to determine effect of encapsulation on microbial fermentation. Data were analyzed according to a complete block design using the MIXED procedure of SAS (SAS Institute, Cary, NC, USA).

RESULTS

For AG and ACG, loading capacity and efficiency were 64.7%, 74.7%, 70.3%, and 78.1%, respectively. Based on the FTIR spectra and scanning electron microscopy, ACG treatment demonstrated more intense and stronger ionic bonds. At pH 6, 36.1% and 29.7% of glycerol was released from AG and ACG, respectively. At pH 2 minimal glycerol was released but pH 8 resulted in 95.7% and 93.9% of glycerol released from AG and ACG, respectively. In vitro microbial data show reduced (p<0.05) fermentation of encapsulated glycerol after 24 h of incubation.

CONCLUSION

The AC polymer provided greater protection in acidic pH with a gradual release of intact glycerol when exposed to an alkaline pH.

Does partial replacement of corn with glycerin in beef cattle diets affect in vitro ruminal fermentation, gas production kinetic, and enteric greenhouse gas emissions?

Five in vitro experiments were conducted with the following objectives: 1) To evaluate the ruminal fermentation of three different single ingredients: corn, glycerin, and starch (Exp. 1 and 2); 2) To assess effects of partially replacing corn with glycerin in beef cattle diets on ruminal fermentation pattern (Exp. 3 and 4); and 3) To evaluate the effects of glycerin inclusion on the extension of ruminal DM digestibility of feeds with high (orchard hay) and low (corn) fiber content (Exp. 5). For Exp. 1 and 2, two in vitro systems (24-bottle AnkomRF and 20-serum bottles) were used in four consecutive fermentation batches to evaluate gas production (GP), fermentation profiles, enteric methane (CH4), and carbon dioxide (CO2) of corn, glycerin, and starch. The 24 h total GP, acetate concentration, and acetate: propionate ratio decreased only when glycerin was added to the diet (P < 0.01). The 48-h total GP and metabolizable energy were greatest for corn (P < 0.01), and similar between glycerin and starch. The starch treatment had the lowest total volatile fatty acids concentration (P = 0.01). Glycerin had greatest CH4 production, lag time, and maximum gas volume of the first pool (P < 0.05). However, the maximum gas volume of the second pool was greatest for corn (P < 0.05), and similar between glycerin and starch. The starch treatment had the greatest specific rates of digestion for first and second pools (P < 0.05). Production of CO2 (mL/g) was greater for corn (P < 0.01), but similar for glycerin and starch. For Exp. 3 and 4, the same systems were used to evaluate four different levels of glycerin [0, 100, 200, and 300 g/kg of dry matter (DM)] replacing corn in beef cattle finishing diets. Glycerin levels did not affect 24 and 48 h total GP, CH4, and CO2 (P > 0.05). The inclusion of glycerin linearly decreased acetate concentration (P = 0.03) and acetate: propionate ratio (P = 0.04). For Exp. 5, two DaisyII incubators were used to evaluate the in vitro dry matter digestibility (IVDMD) of the following treatments: orchard hay; corn; orchard hay + glycerin; and corn + glycerin. Glycerin inclusion decreased orchard hay IVDMD (P < 0.01) but did not affect corn IVDMD (P > 0.05). We concluded that, under these experimental conditions, glycerin has similar energy efficiency when used in replacement of corn and included at up to 300 g/kg in beef cattle diets.

Effects of high concentrations of crude glycerin in diets for feedlot lambs: feeding behaviour, growth performance, carcass and non-carcass traits

The effects of high concentrations of crude glycerin were investigated in diets for feedlot lambs. Forty crossbred (Santa Ines × Dorper) uncastrated male lambs (21.7 ± 2.7 kg bodyweight) were assigned to a complete randomised block and subjected to four experimental diets containing 0, 100, 200, or 300 g crude glycerin/kg DM. Animals were weighed at 14-day intervals and were harvested when they reached ~35 kg bodyweight. The feed intake, feeding behaviour, growth performance, carcass and meat traits, and edible non-carcass components were evaluated. The inclusion of more than 100 g/kg crude glycerin in the diets increased days on feed and decreased DM intake and average daily gain. Crude glycerin increased number of chews and the time spent chewing per feed bolus. There were no effects of crude glycerin on pH and colour of Longissimus muscle at 45 min or 24 h after slaughter, as well as on other carcass and edible non-carcass characteristics. The addition of crude glycerin reduced perirenal fat without detrimental effect on others fat deposition sites. In conclusion, the addition of up to 100 g/kg DM in diets for crossbred finishing lambs seems to be the most interesting strategy, as it promotes greatest animal performance. However, the inclusion of up to 300 g/kg DM of the by-product could be possible depending on glycerin market price and the structure of feedlot operation, with favourable economic results despite high inclusions reflect in greater number of days on feed.

Improved methane production from sugarcane vinasse with filter cake in thermophilic UASB reactors, with predominance of Methanothermobacter and Methanosarcina archaea and Thermotogae bacteria

Biogas production from sugarcane vinasse has enormous economic, energy, and environmental management potential. However, methane production stability and biodigested vinasse quality remain key issues, requiring better nutrient and alkalinity availability, operational strategies, and knowledge of reactor microbiota. This study demonstrates increased methane production from vinasse through the use of sugarcane filter cake and improved effluent recirculation, with elevated organic loading rates (OLR) and good reactor stability. We used UASB reactors in a two-stage configuration, with OLRs up to 45gCODL^-1d^-1, and obtained methane production as high as 3LL^-1d^-1. Quantitative PCR indicated balanced amounts of bacteria and archaea in the sludge (10⁹-10¹⁰copiesg^-1VS), and of the predominant archaea orders, Methanobacteriales and Methanosarcinales (10⁶-10⁸copiesg^-1VS). 16S rDNA sequencing also indicated the thermophilic Thermotogae as the most abundant class of bacteria in the sludge.