Energy concentration and phosphorus digestibility in yeast products produced from the ethanol industry, and in brewers' yeast, fish meal, and soybean meal fed to growing pigs

Comparing feces collection methods for evaluating the apparent digestibility coefficient of brewers' spent yeast in juvenile Atlantic salmon (Salmo salar)

Brewer's spent yeast (BSY), derived from Saccharomyces cerevisiae used in beer production, is a valuable protein source for aquafeeds. Estimations of apparent digestibility coefficients (ADC) for nutrients in BSY are crucial for its inclusion in aquafeeds. ADC estimations for Saccharomyces cerevisiae protein in rainbow are hardly comparable from a methodological point of view, whereas the ADC estimations for BSY protein in Atlantic salmon are only based on stripped feces, which are known to produce underestimations. Therefore, new determinations of ADC of BSY nutrients are necessary for the inclusion of this ingredient in practical diets for salmonids. This study is focused on determining unbiased ADC values for protein and energy from BSY in juvenile Salmo salar. To reduce systematic biases, fecal samples were collected using stripping and decantation methods, which are known to produce under-and overestimations, respectively. 780 fish (25.16 ± 4.88 g) were stocked in six tanks. A reference diet (50% protein, 20% lipid, 1% Cr2O3) was provided to three tanks, and a test diet (70,30 reference diet to BSY) to the other three. ADC for BSY protein was 84.70 ± 1.04% (decantation) and 70.50 ± 4.03% (stripping). For gross energy, stripped feces yielded an ADC of 52.04 ± 5.30%, while decantation resulted in 63.80 ± 1.17%. Thus, ADC estimates were taken as the average of the stripping-value and the decantation-value, resulting in 77.6% for BSY crude protein, which is appreciably higher than previously measured values in S. salar fed undisrupted S. cerevisiae, and in 57.9% for gross energy.

Use of Microorganisms as Nutritional and Functional Feedstuffs for Nursery Pigs and Broilers

The objectives of this review paper are to introduce the structures and composition of various microorganisms, to show some applications of single cells as alternative protein supplements or energy feeds in swine and poultry diets, and to discuss the functional effects of microorganisms as feed additives on the growth performance and intestinal health of nursery pigs and broilers. Microorganisms, including bacteria, yeasts, and microalgae, have been commonly supplemented in animal diets because they are cost-effective, stable, and have quantitative production that provides nutritional and functional benefits to pigs and broilers. Microorganisms could be alternative antibiotics to enhance intestinal health due to bioactive components from cell wall components, which interact with receptors on epithelial and immune cells. In addition, bioactive components could be digested by intestinal microbiota to produce short-chain fatty acids and enhance energy utilization. Otherwise, microorganisms such as single-cell protein (SCP) and single-cell oils (SCOs) are sustainable and economic choices to replace conventional protein supplements and energy feeds. Supplementing microorganisms as feedstuffs and feed additives improved the average daily gain by 1.83%, the daily feed intake by 0.24%, and the feed efficiency by 1.46% in pigs and broilers. Based on the properties of each microorganism, traditional protein supplements, energy feeds, and functional feed additives could be replaced by microorganisms, which have shown benefits to animal's growth and health. Therefore, specific microorganisms could be promising alternatives as nutritional and functional feedstuffs in animal diets.

Evaluation of Torula yeast as a protein source in extruded feline diets

The objective of this work was to evaluate the use of a Torula yeast (TY) on diet processing, palatability, and total tract nutrient digestibility in extruded feline diets. Four dietary treatments were compared, differing by protein source: TY, pea protein concentrate (PP), soybean meal (SM), and chicken meal (CM). Diets were produced using a single-screw extruder under similar processing conditions. Palatability assessment was conducted as a split plate design where both first choice and intake ratio (IR) were determined. Apparent total tract digestibility (ATTD) of nutrients was estimated using Titanium dioxide as an indigestible marker. During diet production, specific mechanical energy of TY and SM (average of 187 kJ/kg) was greater (P < 0.05) than for PP (138 kJ/kg); however, CM was similar to all treatments (167 kJ/kg). Kibble diameter, piece volume, and sectional expansion ratio were greatest for TY (P < 0.05). Additionally, both bulk and piece density were lowest (P < 0.05) for TY. Kibble hardness was lower for TY and SM (P < 0.05; average of 2.10 Newtons) compared to CM and PP (average of 2.90 Newtons). During the palatability trial, TY was chosen first a greater number of times than CM (P < 0.05; 36 vs. 4, respectively), but differences were not found between TY and PP (25 vs. 15, respectively) or TY and SM (24 vs. 16, respectively). Cats had a greater IR (P < 0.05) of TY compared to CM and PP (0.88 and 0.73, respectively). However, there was no difference in preference between TY and SM. ATTD of dry matter (DM) and organic matter (OM) was greater (P < 0.05) for CM (87.43% and 91.34%, respectively) than other treatments. Both DM and OM ATTD of TY were similar (P < 0.05) to PP and SM (average of 86.20% and average of 89.76%, respectively). Ash ATTD was greater (P < 0.05) for cats fed TY and SM (average of 37.42%), intermediate for PP (32.79%), and lowest for CM (23.97%). Crude protein (CP) ATTD of TY was similar to all other treatments (average of 89.97%), but fat ATTD was lower (P < 0.05; 92.52%) than other treatments (93.76% to 94.82%). Gross energy ATTD was greater (P < 0.05) for CM than TY (90.97% vs. 90.18%, respectively); however, TY was similar to PP and SM (average of 90.22%). Total dietary fiber ATTD was similar between TY and CM (average of 66.20%) and greater (P < 0.05) than PP and SM (average of 58.70%). The TY used in this study facilitated diet formation, increased diet preference, and was highly digestible when fed to cats.

Composition and thermal processing evaluation of yeast ingredients as thiamin sources compared to a standard vitamin premix for canned cat food

Significant improvement in thiamin retention of canned cat food has not been achieved by altering processing conditions. Some ingredients, such as yeasts, may supply thiamin able to withstand thermal processing. Therefore, the study objective was to evaluate yeast ingredients as thiamin sources for canned cat food. Six yeast ingredients were screened for thiamin content, and values ranged from 9.9–4,283.8 mg/kg dry matter basis (DMB). Treatments for thermal processing were arranged as a 2×4 factorial with 2 levels of vitamin premix (with or without) and 4 yeast ingredients (NY = none and LBV, BY, or EA from the ingredient screening). Replicates (n = 3) were processed in a horizontal still retort to an average lethality of 79.23 minutes. Thiamin degradation was analyzed as a mixed model with pre-retort thiamin content as a covariate and production day as a random effect. Main effects of vitamin premix and yeast and their interaction were significant at P-values less than 0.05. The Fisher’s LSD post hoc comparison test was used to separate means. On average, experimental formulas retained 33.75% thiamin. The main effect of vitamin premix (average -42.9 mg/kg DMB) was not significant (P > 0.05). Thiamin degradation between NY (-31.3 mg/kg DMB) and BY (-33.8 mg/kg DMB) was similar (P > 0.05) whereas EA (-40.5 mg/kg DMB) and LBV (-55.6 mg/kg DMB) lost more (P < 0.05) thiamin than NY. The experimental formula of EA with vitamin premix (-70.3 mg/kg DMB) lost more (P < 0.05) thiamin than no yeast, BY, or EA without vitamin premix (average -17.4 mg/kg DMB) and all others (average -57.3 mg/kg DMB) were intermediate (P > 0.05). In summary, thiamin from yeast ingredients didn’t exhibit better thermal stability than thiamin mononitrate. However, those ingredients with similar degradation levels or uniquely high thiamin levels may provide added value.

Chemical composition and standardized ileal digestibility of crude protein and amino acid in whole yeast and autolyzed yeast derived from sugarcane ethanol production fed to growing pigs

Objective

This research determined the chemical composition and the apparent and standardized ileal digestibility (AID and SID) of crude protein (CP) and amino acids (AA) in whole yeast and autolyzed yeast derived from sugarcane ethanol production fed to growing pigs.

Methods

Six growing pigs were randomly allocated in a replicated 3×3 Latin square design with 3 diets and 3 periods of 7 days each, resulting in a total of 6 experimental replications. Three assay diets were formulated using whole yeast, autolyzed yeast, or soybean meal as the sole sources of dietary CP and AA. Pigs were allowed to adapt to the assay diets for 5 days. Thereafter, ileal digesta samples were collected continuously for 8 hours on days 6 and 7.

Results

There was no difference in the chemical composition between whole yeast and autolyzed yeast, but whole yeast had low digestibility of CP and AA due to the presence of a rigid cell wall. As conducting autolysis can induce cell wall damage, the AID and SID of CP and AA were greater in autolyzed yeast than in whole yeast.

Conclusion

The information obtained on the SID of CP and AA in both yeast products can be used for the accurate estimation of the bioavailability of CP and AA in feed formulations. The yeast products derived from sugarcane ethanol production are an alternative protein source in pig diets.

Energy concentration and phosphorus digestibility in meat meal, fish meal, and soybean meal fed to pigs

Objective

The objectives of the present study were to determine digestible energy (DE), metabolizable energy (ME), and standardized total tract digestibility (STTD) of phosphorus (P) in meat meal (MM) and to compare these values with those in fish meal (FM), and soybean meal (SBM) fed to pigs.

Methods

Two experiments were conducted to determine energy concentrations and STTD of P in MM, FM, and SBM fed to growing pigs. In Exp. 1, DE and ME in the 3 test ingredients were measured using 24 barrows with initial body weight (BW) of 77.7±8.3 kg. A corn-based diet and 3 diets containing corn and 22% to 30% of each test ingredient were prepared. In Exp. 2, the STTD of P in the 3 test ingredients was measured using 24 barrows (90.9±6.6 kg BW). Three diets were formulated to contain each test ingredient as the sole source of P.

Results

In Exp. 1, the DE and ME values in MM (3,310 and 2,856 kcal/kg dry matter [DM]) were less (p<0.05) than those in FM (4,121 and 3,572 kcal/kg DM) and SBM (4,390 and 4,032 kcal/kg DM). In Exp. 2, FM (64.3%) had greater (p<0.05) STTD of P than SBM (44.8%) with MM (55.8%) having intermediate STTD of P.

Conclusion

The MM contains less energy concentrations compared with FM and SBM, and digestibility of phosphorus in MM does not differ from that in FM and SBM.

Digestible and metabolizable energy concentrations and amino acid digestibility of dried yeast and soybean meal for growing pigs

Energy values and amino acid (AA) digestibility of dried yeast (DY) and soybean meal (SBM) were determined in 2 experiments with growing pigs. Experiment 1 was conducted to determine the digestible energy (DE) and metabolizable energy (ME) in DY and SBM. Thirty barrows with a mean initial body weight (BW) of 20.6 kg (SD = 1.04) were assigned to 5 dietary treatments in a randomized complete block design with period and BW as blocking factors. A reference diet was prepared with corn, canola meal, and soybean oil as energy-contributing ingredients. Four additional diets were prepared by adding 5% and 10% DY or SBM at the expense of energy-contributing ingredients in the reference diet. The ratio of corn, canola meal, and soybean oil was kept consistent across the experimental diets. Each experimental period consisted of 5-d adaptation and 5-d quantitative collection of feces and urine. Test ingredient-associated DE or ME intake (kcal/d) was regressed against test ingredient intake [kg dry matter (DM)/d] to estimate the DE or ME in test ingredients as the slope of linear regression model. The DE in DY was estimated at 3,933 kcal/kg DM, which was not different from the estimated DE in SBM at 4,020 kcal/kg DM. Similarly, there was no difference between DY and SBM in the estimated ME (3,431 and 3,756 kcal/kg DM, respectively). Experiment 2 was conducted to determine the standardized ileal digestibility (SID) of AA in DY and SBM. Twenty-one barrows with a mean initial BW of 20.0 kg (SD = 1.31) were surgically fitted with T-cannulas at the distal ileum and assigned to 3 dietary treatments in a randomized complete block design with BW as a blocking factor. Two semi-purified diets containing DY or SBM as the sole nitrogen source and one nitrogen-free diet (NFD) were prepared. The NFD was used to estimate the basal ileal endogenous losses of CP and AA. Pigs were fed the 3 diets for 5 d as adaptation, followed by 2 d of feeding with ileal digesta collection. The SID of AA, except Gly and Pro, in DY was less (P < 0.05) than in SBM. The SID of indispensable AA in DY ranged from 64.1% for Thr to 85.2% for Arg, and those in SBM ranged from 83.9% for Thr to 91.8% for Arg. In conclusion, energy values of DY are not different from those of SBM, whereas AA in DY is less digestible than in SBM. The estimated DE and ME as well as the SID of AA in DY and SBM can be used in diet formulation for growing pigs using these ingredients.

Effects of a Hatchery Byproduct Mixture on Growth Performance and Digestible Energy of Various Hatchery Byproduct Mixtures in Nursery Pigs

The objectives were to determine effects of a hatchery byproduct mixture (HBM) on growth performance and to measure digestible energy concentrations in various HBM. In the growth performance experiment, 96 pigs (initial body weight = 9.6 ± 0.8 kg) were assigned to 4 dietary treatments in a randomized complete block design with 6 blocks. Each treatment consisted of 6 replicate pens with 4 pigs comprising 2 barrows and 2 gilts. Pigs were fed graded concentrations of HBM at 0%, 3.33%, 6.67%, and 10.00% for 14 days. In the energy digestibility experiment, 10 barrows (initial body weight = 11.5 ± 0.4 kg) were employed to determine digestible energy in HBM. A basal diet based on corn and soybean meal and 4 additional diets containing 25% of 4 different HBM were prepared. The marker-to-marker method was employed for total collection and the experimental design was a replicated 5 × 4 Latins square design. Growth performance was not compromised as the inclusion rate of HBM increased up to 10%. Digestible energy of HBM ranged from 2772 to 3887 kcal/kg as-is basis. In conclusion, HBM can be used in nursery pig diets and different energy values should be used for each HBM.

Torula yeast has greater digestibility of amino acids and phosphorus, but not energy, compared with a commercial source of fish meal fed to weanling pigs

Three experiments were conducted to test the hypothesis that the standardized ileal digestibility (SID) of AA, concentrations of DE and ME, and the standardized total tract digestibility (STTD) of P in a source of torula yeast are not different from values obtained in Menhaden fish meal. In experiment 1, six weanling barrows (initial BW: 11.7 ± 0.4 kg) were prepared with a T-cannula in the distal ileum and allotted to a replicated 3 × 3 Latin square design with 3 diets and 3 periods. In each period, there were 5 d of adaptation and 2 d of collection. Two cornstarch-based diets using the torula yeast or fish meal as the sole source of AA and a N-free diet were formulated. The SID of CP and all AA was greater (P < 0.05) in torula yeast than in fish meal. In experiment 2, 24 weanling barrows (initial BW: 14.4 ± 1.1 kg) were individually housed in metabolism crates and allotted to a corn-based diet or 2 diets based on a mixture of corn and torula yeast or corn and fish meal. Feces and urine samples were collected for 4 d following a 5-d adaptation period. There were 8 replicate pigs per diet and fecal and urine materials were collected. Results of this experiment indicated that there were no differences in the concentration of DE and ME (DM basis) between torula yeast and fish meal. In experiment 3, a total of 32 weanling barrows (initial BW: 11.9 ± 1.1 kg) were allotted to 4 diets and 8 replicate pigs per diet. Pigs were placed in individual metabolism crates. The torula yeast or fish meal were used in 2 diets containing either 0 or 500 units of microbial phytase. Feces samples were collected as described for experiment 2. The STTD of P in torula yeast was greater (P < 0.05) than in fish meal, but regardless of ingredient, there was no effect of the inclusion of phytase in the diets. In conclusion, the SID of AA and the STTD of P in torula yeast is greater than in fish meal, but values for the concentration of DE and ME in torula yeast are not different from those in fish meal. Therefore, the torula yeast that was used in the present experiments may be included at the expense of fish meal in diets fed to weanling pigs if the concentration of standardized ileal digestible AA is considered in the formulation.

Effect of live yeast supplementation to gestating sows and nursery piglets on postweaning growth performance and nutrient digestibility

The objectives of the present study were to determine the effects of live yeast (LY) supplementation of sows during gestation and lactation and to determine the effects of supplementation of their offspring after weaning on growth performance and nutrient digestibility. A total of 40 sows were assigned to 2 dietary treatments (control vs. LY) based on parity and expected farrowing date. Birth weight, weaning weight, litter size, and mortality were measured. After weaning, 128 mixed-sex piglets (64 from each sow treatment) were selected based on their source litter and initial BW, and randomly assigned to 2 treatments (control or LY) at 4 pigs per pen (total of 32 pigs per treatment) for a 6-wk growth performance study. At the end of the growth performance trial, 2 barrows from each pen were moved to metabolism crates for total fecal collection for a digestibility trial. Addition of LY to the sow diets had no effects on birth weight, weaning weight, litter size at birth, and mortality. Piglets had greater BW on days 21 and 42 post-weaning when sows were fed diets supplemented with LY, and overall ADG was greater in piglets from sows that received LY (P < 0.05). There was no effect of sow and nursery diets on overall ADFI and G:F intake. Supplementing diets with LY during the nursery phase increased apparent total tract digestibility (ATTD) of DM, GE, and phosphorus (P) during this phase. The ATTD of GE was also greater in piglets from sows that received LY. In conclusion, LY supplementation of diets during gestation and lactation and during the nursery phase could increase ADG and ATTD of DM, GE, and P in the offspring, and this may lead to a greater lifetime growth performance in the offspring.

Energy Concentration and Phosphorus Digestibility in Hatchery Byproducts Fed to Nursery Pigs

Simple Summary

There is limited information on nutritional value of hatchery byproducts as a swine feed ingredient. The objective of this study was to determine energy concentrations and phosphorus digestibility of hatchery byproducts fed to nursery pigs. Test ingredients were infertile eggs, unhatched eggs, culled chicks, and a mixture of the three. Culled chicks had the greatest energy concentrations, whereas infertile eggs had the lowest values. The standardized total tract digestibility of phosphorus in infertile eggs was greater than that in unhatched eggs, culled chicks, and the mixture. Based on the current results, feed formulation would be possible when using hatchery byproducts in swine diets.

Abstract

The objective was to measure energy concentrations and standardized total tract digestibility (STTD) of phosphorus (P) in hatchery byproducts. In Experiment 1, 20 nursery barrows were used to measure energy concentrations in hatchery byproducts. A basal diet based on corn and dried whey and four additional diets containing 25% of infertile eggs, unhatched eggs, culled chicks, or a mixture of the three hatchery byproducts were prepared. In Experiment 2, the STTD of P was measured using 20 nursery barrows. Four diets containing 25% of the same hatchery byproducts used in Experiment 1 as the sole source of P were prepared, and a P-free diet was prepared to measure basal endogenous losses of P. The marker-to-marker method was employed for total collection. Metabolizable energy in culled chicks was the greatest (4560 kcal/kg as-is basis; p < 0.05), whereas infertile eggs had the lowest value (2645 kcal/kg as-is basis; p < 0.05). The STTD of P in infertile eggs (81.7%) was greater than that in unhatched eggs, culled chicks, and the mixture (61.6, 53.9, and 47.4%, respectively; p < 0.05). In conclusion, culled chicks had the greatest metabolizable energy and infertile eggs had the greatest phosphorus digestibility among the test ingredients.

Methodological aspects of determining phosphorus digestibility in swine: A review

The role of phosphorus (P) in swine nutrition has been taken on new significance in recent years. Methods to determine the available phosphorus (AP) content of swine feeds include relative bioavailability (RBV), apparent total tract digestibility (ATTD), standardized total tract digestibility (STTD), and true total tract digestibility (TTTD). The RBV of P is determined by measuring bone ash or bone P, whereas the ATTD of P is determined by calculating the difference between P intake and P excretion in feces. Recent research has shown that the use of ATTD of P underestimates the AP due to the existence of endogenous P in feces and digesta. The STTD can be calculated from ATTD by taking basal endogenous phosphorus losses (EPL) into consideration. The basal EPL in pigs can be measured by feeding a P-free diet. Values for STTD of P are believed to be additive in mixed diets but not for ATTD of P. The regression method is a common approach to determine total EPL and TTTD of P, which measures the linear relationship between fecal P excretion and the dietary intake of total P. In addition, in vitro methods such as the bionic enzymatic method are being increasingly utilized because they can be done quickly and simply. Several dietary factors such as P and Ca concentrations, phytate, Ca to P ratio and vitamin D may affect AP. This review summarizes the evolution of methods to measure AP and factors that can affect AP, which may provide information to formulate swine diet more accurately. Moreover, the knowledge about AP may help to reduce the P waste in swine production and thus decrease its impact on the environment.

Influence of dietary crude protein and phosphorus on ileal digestion of phosphorus and amino acids in growing pigs

A study was conducted to investigate the effect of dietary CP levels on ileal P digestion in growing pigs. A total of 18 ileal-cannulated pigs (44.2 ± 3.2 kg initial BW) were used in a duplicated 9 × 3 incomplete Latin square design, with 9 treatments and three 7-d experimental periods giving 6 replicates per treatment. The 9 treatments consisted of 1 N-free diet to estimate basal endogenous loss of AA and 8 corn-soybean meal-based diets in a 2 × 4 factorial arrangement, which included 2 CP levels (6.9 or 13.4%) and 4 apparent total tract digestible P (ATTDP) levels (0.09, 0.16, 0.24, or 0.32%). Soybean meal and monocalcium phosphate were used to adjust the CP level and ATTDP level, respectively. Limestone was included in diets to maintain a Ca:ATTDP ratio of 2.5 across treatments. Ileal digesta was continuously collected for 10 h on the last 2 d of each 7-d experimental period. The ileal digesta samples were lyophilized and analyzed to calculate ileal digested N and P. Data were analyzed using PROC MIXED of SAS (9.3) and contrasts were used to test the linear and quadratic effects of increasing levels of P within each CP level. In the low-CP group (6.9%), the ileal digested P was 0.71, 1.16, 1.64, and 2.03 g/kg DMI for diets that contained 0.09, 0.16, 0.24, and 0.32% ATTDP, respectively, and was 0.70, 1.54, 2.03, and 1.99 g/kg DMI, respectively, for their counterparts in the high-CP group (13.4%). A low dietary CP level decreased ( < 0.05) ileal digested P (g/kg DMI). The ileal digested P (g/kg DMI) linearly increased ( < 0.01) with increasing ATTDP levels in the low-CP group, but the pattern was linear ( < 0.01) and quadratic ( < 0.01) in the high-CP group. In the low- and high-CP diets, the determined true ileal digestibility of P in monocalcium phosphate was 54.4 and 75.6%, respectively. In conclusion, this research indicated that the ileal digestion of P could be limited by protein deficiency. The dietary CP level should be considered in P digestibility-related studies.

Standardized total tract digestibility of phosphorus in various inorganic phosphates fed to growing pigs

An experiment was conducted to determine the standardized total tract digestibility (STTD) of phosphorus (P) in five sources of inorganic phosphate fed to growing pigs, including dicalcium phosphate (DCP), monodicalcium phosphate (MDCP), monocalcium phosphate (MCP), tricalcium phosphate (TCP) and monosodium phosphate (MSP, reagent grade). Six barrows (42.4 ± 1.1 kg) individually housed in metabolism crates were allotted to a 6 × 6 Latin square design with six dietary treatments and six periods. Each experimental period consisted of a 4 day adaptation period and a 5 day collection period. The five experimental diets contained 0.24 to 0.34% of P from each inorganic phosphate as a sole source of P. A P-free diet was also prepared to estimate the basal endogenous loss of P. The STTD of P in MSP (94.9%) was not different from the STTD of P in MCP (93.0%), but was greater (P < 0.05) than that in DCP, MDCP and TCP (87.0, 86.5 and 71.3%, respectively). In conclusion, digestibility of P in reagent-grade MSP was greater than that in feed-grade inorganic phosphates such as DCP, MDCP and TCP, and digestibility of P in DCP and MDCP was greater than that in the TCP.

Yeast derived from lignocellulosic biomass as a sustainable feed resource for use in aquaculture

The global expansion in aquaculture production implies an emerging need of suitable and sustainable protein sources. Currently, the fish feed industry is dependent on high-quality protein sources of marine and plant origin. Yeast derived from processing of low-value and non-food lignocellulosic biomass is a potential sustainable source of protein in fish diets. Following enzymatic hydrolysis, the hexose and pentose sugars of lignocellulosic substrates and supplementary nutrients can be converted into protein-rich yeast biomass by fermentation. Studies have shown that yeasts such as Saccharomyces cerevisiae, Candida utilis and Kluyveromyces marxianus have favourable amino acid composition and excellent properties as protein sources in diets for fish, including carnivorous species such as Atlantic salmon and rainbow trout. Suitable downstream processing of the biomass to disrupt cell walls is required to secure high nutrient digestibility. A number of studies have shown various immunological and health benefits from feeding fish low levels of yeast and yeast-derived cell wall fractions. This review summarises current literature on the potential of yeast from lignocellulosic biomass as an alternative protein source for the aquaculture industry. It is concluded that further research and development within yeast production can be important to secure the future sustainability and economic viability of intensive aquaculture. © 2016 Society of Chemical Industry.

The Role of Biofuels Coproducts in Feeding the World Sustainably

One of the grand challenges facing our society today is finding solutions for feeding the world sustainably. The food-versus-fuel debate is a controversy embedded in this challenge, involving the trade-offs of using grains and oilseeds for biofuels production versus animal feed and human food. However, only 6% of total global grain produced is used to produce ethanol. Furthermore, biofuels coproducts contribute to sustainability of food production because only 1% to 2.5% of the overall energy efficiency is lost from converting crops into biofuels and animal feed, and approximately one-third of the corn used to produce ethanol is recovered as feed coproducts. Extensive research has been conducted over the past 15 years on biofuels coproducts to (a) optimize their use for improving caloric and nutritional efficiency in animal feeds, (b) identify benefits and limitations of use in various animal diets,