Amino Acid Digestibility Research Articles

Effect of protease supplementation on amino acid digestibility of soybean meal fed to growing-finishing pigs in two different ages.

This study was conducted to investigate the effect of protease inclusion level in two different ages on the apparent (AID) and standardized (SID) ileal digestibility of crude protein (CP) and amino acids (AA) in soybean meal (SBM) fed to growing-finishing pigs. Ten cannulated pigs (21kg ± 2kg) were assigned to experimental diets in a duplicate 5 × 5 Latin square design. In Phase I (23 to 30 kg-pigs, 90 ± 17 days of age), ileal digesta was collected in 5 periods of 7d (5d adaptation and 2d ileal digesta collection). In phase II, (50 to 65 kg-pigs, 140 ± 17 days of age), ileal digesta was collected in 5 more periods of 7 d. For both phases, a corn starch-based diet was formulated with SBM as the sole source of CP and AA and containing titanium as an indigestible marker. Protease was supplemented at 0, 15,000, 30,000, and 45,000 NFP/kg of feed (0, 25, 50, and 75g/ton of ProAct 360®). A nitrogen-free diet was used to estimate basal ileal endogenous AA losses. Pigs were fed at 4% of their body weight, which was adjusted at the end of each period. Orthogonal polynomial contrasts were used to determine the linear and quadratic effects of dietary protease supplementation in each phase. In phase I, increasing levels of protease resulted in a linear increase (P<0.10) in SID for the 7/11 indispensable AA (Except Arg, His, Met + Cys, and Trp) and the average of all dispensable AA. In phase II, the SID of Ile, Leu, Met, Met + Cys, Val, the average of all indispensable AA, and 4/7 dispensable AA were quadratically increased (P<0.10). In most cases, supplementation with 30,000 NFP/ kg of feed (50g/ton) resulted in the greatest increase in AA digestibility. However, the linear response in phase I for some AA suggests that diets for younger pigs could be supplemented with a greater level (45,000 NFP/kg or 75g/Ton of feed). Interestingly, younger pigs had consistently increased (P<0.10) SID of CP and 15/18 AA (Except Arg, Cys, and Ser), being ~5.6% greater for indispensable AA when compared to older pigs. In conclusion, dietary protease supplementation can increase the SID of AA in soybean meal in both growing and finishing periods. Pig age can potentially influence AA digestibility, possibly related to a greater ileal endogenous AA flow in younger pigs. However, this fact warrants further investigation.

Research Note: Proteases effect on soybean meal: enzyme product and area of production differences on standardized ileal amino acids digestibility of broiler chickens

This study evaluated the effects of two protease products added to feeds having two soybean meal (SBM) sources (South and North of Brazil). A total of five hundred and sixty, 21 d male broiler chickens were allocated into 7 dietary treatments: a nitrogen-free diet (NFD) and other six diets prepared with a 40% replacement of the NFD with each SBM source. Two commercial protease products (RONOZYME® ProAct and ProAct 360TM) were added at 15,000 PROT and 30,000 NFP per kg feed, respectively. After 5-day diet adaptation, all birds were euthanized for ileal digesta collection. Results show that the North SBM sample was inherently higher (P < 0.05) in apparent ileal digestibility (AID) of dry matter (DM), nitrogen (N), and the standardized ileal amino acid digestibility (SIAAD) compared to South SBM sample. The DM digestibility and SIAAD of North SBM sample were not different from the un-treated control and protease treatments (P > 0.05, except Val and Ile, which had higher digestibility with ProAct 360). The DM digestibility and SIAAD from South SBM sample were increased (P < 0.05, except Met, Asp and Cys) with both supplemental proteases. Correlation analysis showed that AA digestibility of the two SBM samples were negatively associated with the effect of protease products. These data demonstrated that the SIAAD of SBM was influenced by SBM source with the South SBM sample being lower than that from the North while the protease effects were more evident in the SBM sample from South; responses of ProAct 360 were superior to ProAct. Exogenous proteases can enhance nutritional value of SBM, particularly for those with inherently low amino acid digestibility.

Nutritional values of soybean meal from different sources in multiparous sows

This study determined the available energy content, apparent total tract digestibility (ATTD) of nutrients, and ileal amino acid (AA) digestibility of soybean meal (SBM) from different sources in non-gestating, non-lactating sows. In Exp. 1, 24 multiparous Landrace × Yorkshire (LY) sows (parity 3–5) were allotted to a replicated 12 × 3 Youden square design consisting of 12 diets and 3 periods. The 12 diets included 11 test diets containing SBM from different sources and a corn-based diet. Each period included a 5-d adaptation and a 5-d total fecal and urine collection. In Exp. 2, 8 multiparous LY sows (parity 3–5) were allotted to a replicated 4 × 3 Youden square design with 4 diets and 3 periods. The 4 diets included a nitrogen-free diet and 3 SBM diets (3 representative SBM samples were selected from Exp. 1). Our results showed that the coefficient of variation of ether extract, crude fiber, neutral detergent fiber, and acid detergent fiber levels in 11 SBM samples were > 20%. There were no differences in digestible energy (DE), metabolizable energy (ME), and the ATTD of gross energy, nitrogen, and neutral detergent fiber values between different SBM samples (P > 0.05). Additionally, no differences in AA digestibility were identified among the 3 representative SBM samples (P > 0.05). In conclusion, there were no differences in DE, ME, and AA digestibility between different SBM samples fed to multiparous non-gestating sows. When formulating diets for sows, it is important to consider the differences in the nutritional value of SBM at different physiological stages.

Interactive effect of dietary metabolizable energy levels with amino acid density in male broiler chickens: carcass yield, nutrient intake, digestibility and excretion

This study aimed to assess the interactive effects of ME and digestible amino acid (AA) densities on carcass yield, breast meat quality, nutrient digestibility, and excretion in male broiler chickens. Twelve experimental diets arranged as a 4 × 3 factorial array with 4 levels of ME (standard, -50, -100, -150 kcal) and 3 digestible AA (standard, +3.0 and +6.0%) were offered to 2400 day-old male Ross 308 broiler chickens. Diets were replicated 8 times with 25 birds per replicate, and fed for starter (0-10 d), grower (11-24 d), finisher (25-35 d), and withdrawal (36-42 d) phases, with consistent reduction of ME and increase in AA density for each phase. On day 24, three birds per replicate were euthanized to collect digesta for nutrient digestibility and excreta samples were collected on day 40 for nutrient excretion analysis. On day 42, four birds per replicate were euthanized for carcass yield and quality evaluation. The birds' feed intake, along with calculated ME and AA levels, were used to determine nutrient intake. No interactions were observed between ME and AA densities on carcass characteristics, nutrient digestibility, and excretion (P > 0.05). Reducing ME density linearly increased breast meat yield and decreased abdominal fat, regardless of AA density (P < 0.01). Increasing AA density enhanced breast meat yield but increased white striping and woody breast scores in a linear manner (P < 0.01). Dietary treatments didn't affect ileal digestibility of crude protein and gross energy, except for improved starch digestibility with 6.0% AA density (P < 0.01). Crude fat digestibility decreased linearly with decreased ME density, while reducing ME density linearly decreased fat, calcium, copper, and manganese excretion (P < 0.01). Increasing AA density linearly increased nitrogen excretion, but reduced calcium and iron excretion (P < 0.05). Over the entire production period lower ME and higher AA density increased digestible lysine intake (mg/bird/day; P < 0.01). In summary, these results suggest that dietary ME and AA density, independently, affect carcass yield, breast meat quality, nutrient digestibility, and excretion.

Effect of dietary β-mannanase supplementation on growth performance and nutrient retention in broiler chickens fed corn-soybean meal-based diets with low energy and amino acid density

The present study was conducted to evaluate the effect of two different β-mannanases on growth performance and nutrient retention of broiler chickens fed a diet with low energy and amino acid density. A total of 312 one-day-old male broiler chickens (Ross 308) were placed in floor pens and fed a standard starter diet for 16 days. They were then randomly moved to stainless steel cages and distributed into three groups, with 13 replicates of 8 chickens each. The control group received a corn-soybean meal-based grower diet with reduced metabolizable energy by ∼100 kcal/kg and a 10-12% reduction of digestible amino acids (lysine, methionine, and threonine). Titanium oxide was added at 0.5% of diet as an indigestible marker. The other groups were fed the same diet supplemented with either β-mannanase A derived from Thermothelomyces thermophilus (100 g β-mannanase/MT grower diet) or β-mannanase B derived from Paenibacillus lentus (350 g β-mannanase/MT grower diet). The trial lasted for 7 days from d 17 to d 23, comprising 4 days of acclimatization followed by 3 days of sample collection. Final body weight (d 23), body weight gain (d 17-23), and feed intake (d 17-23) of broiler chickens did not differ among the groups. However, both β-mannanases significantly improved the feed conversion ratio during d 17-23 (P = 0.039) and nitrogen retention (P = 0.028) in broiler chickens compared to the control group. Moreover, dietary supplementation with β-mannanase A significantly increased dry matter retention (P = 0.050), organic matter retention (P = 0.028), and nitrogen-corrected apparent metabolizable energy (AMEn; P = 0.033) compared to the control group. In conclusion, supplemental β-mannanase, regardless of the product, improved the growth performance of broiler chickens by improving nutrient retention and dietary AMEn.

Evaluation of protease plus a precision-biotic on body weight gain and feed conversion ratio in broilers from 0 to 42 days of age

This study aims to evaluate the effects of a protease combination with a precision biotic on body weight gain (BWG) and feed conversion ratio (FCR) of broilers from day 0 to 42. 1,400 Cobb 500 male chicks were reared on seven different diets, including an unrestricted positive control (PC–Diet 1) and a negative control (NC–Diet 2) with slightly reduced crude protein, apparent metabolizable energy (AME), and digestible amino acids. Five additional treatment diets were formulated using the negative control and varying concentrations of a protease (Diets 3-4; 33ppm and 50ppm, respectively) and in combination with a precision biotic (Diets 5-7; 33ppm + 700ppm; 50ppm + 500ppm; and 50ppm + 700ppm, respectively). The PC treatment showed significantly different feed intake and FCR compared to all other treatments in all production phases (P &lt; 0.05). There are no significant differences in non-PC treatments in all production phases for BWG and FCR (starter p=0.230 and 0.300; grower p=0.443 and 0.237; finisher p=0.450 and 0.896; overall p=0.111 and 0.497, respectively), nor is there any in terms of mortality (p=0.800). These findings may provide valuable information to producers to optimize flock performance efficiently and cost-effectively.

Standardized Ileal Digestibility of Amino Acids in Hybrid Rye Ground to Two Particle Sizes and Fed With or Without Multienzyme Supplement to Young Growing Pigs.

A newly developed hybrid rye with enhanced ergot resistance has potential as an alternative energy source for pigs. An experiment was conducted to evaluate the effects of particle size (PS) and multienzyme supplement (MES) on the apparent total tract digestibility (ATTD) of energy and nutrients and the standardized ileal digestibility (SID) of amino acids (AA) in hybrid rye fed to growing pigs. Bono and Gatano, two hybrid rye varieties, were ground to either a coarse (1111 and 1210 μm) or a fine (594 and 717 μm) PS using a hammer mill. Eighteen ileal-cannulated barrows (initial BW = 18.2 ± 1.0 kg) were randomly assigned to 1 of 9 dietary treatments in a replicated 9 × 3 incomplete Latin square design to give six observations per treatment. Among the nine experimental diets, eight featured two hybrid rye varieties (Bono or Gatano), either coarsely or finely ground, as the only source of AA with or without MES, while an N-free diet was used to estimate the endogenous losses of AA at the distal ileum. All diets contained titanium dioxide as an indigestible marker. Each period lasted 9 days, with the first 5 days being for adaptation followed by 2 days each for faecal and ileal digesta collection. Data were analysed using the MIXED procedure of SAS, with the final model having variety, PS, MES, their two-way interactions, and a three-way interaction. No interactions were noted except that the apparent ileal digestibility and SID of crude protein (CP) and most AA in Gatano had greater effects of MES than Bono (Variety × MES; p < 0.05). The ATTD of dry matter (DM), gross energy (GE) and CP were greater (p < 0.05) in Bono diets than in Gatano diets. Finely ground hybrid rye diets had higher (p < 0.05) ATTD of neutral detergent fibre assayed with a heat stable amylase and expressed inclusive of residual ash (NDF) and ether extract compared to coarsely ground hybrid rye diets. Dietary MES supplementation increased (p < 0.05) the ATTD of DM, GE, CP, NDF, acid detergent fibre expressed inclusive of residual ash, and ash in hybrid rye diets. In conclusion, the nutrients digestibility of hybrid rye can be affected by its variety. PS reduction improved the nutrient digestibility in hybrid rye, and MES supplementation improved the energy and AA digestibility in hybrid rye fed to growing pigs.

Effect of temperature on the digestibility of non-starch polysaccharide-rich ingredients in Nile tilapia (Oreochromis niloticus)

This study aimed to investigate the interaction effect of NSP-rich ingredient and rearing temperature on nutrient digestibility of the ingredients in Nile tilapia. Seven NSP-rich ingredients were tested: insect meal, wheat bran, palm kernel meal, rapeseed meal, sunflower meal, dried distillers grains with solubles (DDGS) from corn, and rice bran. A balanced control diet was formulated followed by the formulation of seven test diets by mixing 30 % of each test ingredient with 70 % of the control diet and fed to fish reared at 24 or 32 °C. At each temperature, 35 all male Nile tilapia with an initial mean weight of 45.0 g at 24 °C and 43.8 g at 32 °C were housed in each of 24 glass-tanks, each containing 60 L of water. The diets were administered to the fish groups in triplicate over 42 d in a recirculating aquaculture system. Fecal samples were collected and analyzed alongside the diets to determine nutrient digestibility. Digestibility of all nutrients differed between ingredients (P < 0.001) at both temperatures. Wheat bran had the lowest NSP digestibility at both 24 (1.9 %) and 32 °C (9.7 %). At 24 °C, DDGS showed the highest NSP and protein digestibility (41.4 and 90.3 %), while at 32 °C insect meal showed the highest NSP and fat digestibility (59.8 and 97.5 %). Insect meal showed the highest fat digestibility (97.4 %) also at 24 °C. An interaction effect between ingredient and temperature was observed for the digestibility of NSP, carbohydrate, protein, amino acids, magnesium, and dry matter (P ≤ 0.035). Some nutrients showed reduced digestibility for some ingredients at the higher temperature, but in most of the cases temperature increased nutrient digestibility, with insect meal exhibiting a 20 % increase in NSP digestibility. In conclusion, water temperature affect nutrient digestibility, but the extend of the temperature effect differs between ingredients.

Effects of feed particle size, calcium concentration and phytase supplementation on InsP6 degradation in broiler chickens fed pelleted diets

ABSTRACT 1. The objective of the trial was to study the single and interactive effects of feed particle size in pelleted feed, dietary calcium (Ca) concentration and microbial phytase supplementation in broiler chickens. The studied traits were myo-inositol (1,2,3,4,5,6) hexakis (dihydrogen phosphate) (InsP6) degradation, pre-caecal digestibility of phosphorus (P), Ca and amino acids (AA) and retention of P, Ca and nitrogen (N). 2. Male Ross 308 broiler chickens were housed in metabolism units in groups of 10 and allocated to one of eight diets with seven pen replicates per diet. The 2 × 2 × 2-factorial arrangement included coarse and fine feed particle size (309 or 222 µm), low and high Ca concentration (4.9 and 7.2 g/kg) and without or with phytase supplementation (1,000 FTU/kg). 3. Pre-caecal InsP6 disappearance was higher with coarse than fine feed particle size when no phytase was added (54 vs. 48%) but not when phytase was added (74%; p = 0.046). High dietary Ca feeds decreased pre-caecal InsP6 disappearance (67 to 59%) and P digestibility (65 to 55%; p < 0.001). Gizzard pH was lower with coarse than fine feed particle size and higher with high Ca than low Ca (p < 0.001). Pre-caecal digestibility of most AA was approximately 3.5%-points lower with high Ca without phytase compared to the other treatments (p ≤ 0.047). Coarse feed particle size caused higher pre-caecal AA digestibility than fine particle size (~2%-points; p ≤ 0.031). InsP6 disappearance in the crop increased at high Ca concentration when phytase was added (22 vs. 37%; p = 0.011). 4. Coarser feed particle size in pellets increased gastrointestinal InsP6 degradation and nutrient digestibility, likely owing to effects on the gizzard functions. Additional Ca supply exerted antinutritive effects that was not compensated for by using coarser feed particles.

Assessment of two diet types in reduced-crude protein diets with or without phytase supplementation – implications on key phenotypic responses in 21-day-old broiler chickens

ABSTRACT 1. Two concurrent experiments were conducted to investigate the effect of using the crude protein (CP) value of supplemental amino acids (AA) in formulating reduced-crude protein (RCP) diets. The RCP diets formulated without accounting for CP values of supplemental AA (RCPN) or otherwise (RCPY) or a positive control (PC) diet were fed without (Experiment 1) or with (Experiment 2) phytase. 2. Each experiment utilised 105 male broiler chicks. Birds were provided a common starter diet from d 0–7. On d 21, ileal digesta were collected from the distal half of the ileum. For mRNA expression analysis, tissues were collected from the mid-jejunum and the liver. Excreta grab samples were collected for analysis for N content. 3. In Experiment 1, there was a stepwise decrease (p < 0.01) in weight gain and excreta N for birds receiving PC, RCPN and RCPY diets. The coefficients of ileal digestibility of His, Leu, Phe and Trp were greater (p < 0.05) in birds that received RCPY rather than the PC diets. The relative mRNA expression of CAT1 was greater (p < 0.05) for birds that received the PC diet. 4. In Experiment 2, growth performance and excreta N were not different between the PC and RCPN diets, but weight gain, feed intake and excreta N were greater (p < 0.01) in birds receiving PC or RCPN diets. The coefficients of digestibility were greater (p < 0.01) in RCP than PC diets for Lys, Thr, Cys, Gly and Ser. The mRNA expression for S6kinase and PRKAβ2 was greater (p < 0.05) for birds fed RCPN compared to PC. 5. In conclusion, accounting for the N content of supplemental AA during feed formulation for RCP diets will influence the effect of CP reduction on growth performance and ileal amino acid digestibility.

Energy Values and Standardized Ileal Digestibility of Amino Acids in Fermented Soybean Meal Fed to Growing Pigs.

This study aimed to evaluate the digestible energy (DE), metabolizable energy (ME), and standardized ileal digestibility (SID) of amino acids (AA) in fermented soybean meal (FSBM) fed to growing pigs. In experiment 1, twenty-two growing pigs (Duroc × Landrace × Yorkshire; 32.0 ± 4.2 kg BW) were fed one of 11 diets in a replicated 11 × 3 incomplete Latin square design to determine the DE and ME of FSBM. The diets included a corn-based diet and 10 experimental diets formulated by replacing the corn with 29.10% FSBM. In experiment 2, eleven growing pigs (Duroc × Landrace × Yorkshire; 24.3 ± 2.3 kg BW) were surgically equipped with a T-cannula and arranged in an 11 × 6 incomplete Latin square design with 11 diets and six periods. The diets included an N-free diet and 10 experimental diets containing 40% FSBM as the sole source of AA. The results showed that the contents of dry matter (DM), gross energy, crude protein, crude fiber, neutral detergent fiber, acid detergent fiber, calcium, and phosphorus averaged 91.83% (ranging from 89.24 to 94.55%), 18.44 MJ/kg (ranging from 18.00 to 18.95 MJ/kg), 50.63% (ranging from 50.00 to 51.81%), 4.51% (ranging from 3.41 to 5.40%), 9.17% (ranging from 7.02 to 10.30%), 6.38% (ranging from 4.97 to 7.45%), 0.32% (ranging from 0.29 to 0.34%), and 0.67% (ranging from 0.61 to 0.84%), respectively. The average DE and ME were 17.55 and 16.33 MJ/kg DM, respectively, with ranges of 15.72 to 18.80 MJ/kg DM and 14.30 to 17.72 MJ/kg DM, respectively. Significant differences were observed in the SID of essential AA (p < 0.05), except for Thr and Arg. The SID of Lys, Met, Trp, and Thr ranged from 68.13 to 83.27% (mean = 76.62%), 62.23 to 89.30% (mean = 75.25%), 72.30 to 90.29% (mean = 80.96%), and 74.17 to 84.41% (mean = 77.90%), respectively. These results indicate significant variability in chemical composition, energy content, and the SID of AA among the selected FSBM samples. The chemical composition of FSBM can be used to predict DE and ME values.

Dietary superdosing of phytase positively affects growth, mineral utilization and amino acid availability of channel catfish (Ictalurus punctatus)

The present study investigated the effects of supplementing high levels (superdosing) of dietary phytase on growth performance, mineral utilization and digestibility of amino acids in different regions of the gastrointestinal (GI) tract of fingerling channel catfish. The negative control (NC) diet was formulated with primarily soybean meal as a protein feedstuff which contributed 0.61 % total phosphorus (P) but was deficient in available P at 0.11 % of diet. Five other diets were formulated either with supplemental monocalcium phosphate at 1 % of diet in the positive control (PC), or supplemented with Quantum Blue phytase (AB Vista, Plantation, Florida) at 1000, 2000, 4000, or 8000 phytase units (FTU)/kg of diet. Groups of 20 catfish were each stocked into 24 aquaria operated as a closed, recirculating system with biological and mechanical filtration. All dietary treatments were assigned randomly to quadruplicate aquaria and initially fed at 6 % of total body weight per day. Feed quantities were adjusted weekly after weighing all fish in each aquarium as a group, and feeding levels were maintained close to apparent satiation throughout the 8-week feeding trial. Phytase supplementation significantly (P < 0.05) increased various responses of channel catfish including weight gain, feed efficiency, and protein retention compared to catfish fed the NC diet, resulting in values that were similar to catfish fed the PC diet. Moreover, catfish fed the phytase-supplemented diets had higher bone ash, calcium (Ca), magnesium (Mg), P, manganese (Mn), and zinc (Zn), as well as retention of Ca, Mg, P, iron (Fe), Mn, and Zn in whole-body tissues. Additionally, apparent availability of P from the posterior intestinal region increased with dietary phytase supplementation, with reduced excretion of nitrogen, Ca, Mg, P, copper (Cu), Mn, and Zn observed in comparison to fish fed the NC diet. Apparent digestibility coefficients for many of the indispensable and dispensable amino acids were increased by phytase supplementation, except for histidine, methionine, threonine, and taurine. This improvement in amino acid availability occurred only in the posterior region of the gastrointestinal tract. Channel catfish fed the diet containing 4000 FTU/kg diet had the highest postprandial plasma phosphorus level most of the time, except at 24 h after feeding. Based on these various responses, the optimal dietary phytase dosage was determined to average 5492 FTU/kg diet.

An Estimation of the Requirements of the Standardized Ileal Digestible Tryptophan, Valine, Isoleucine and Methionine on Young Pigs’ (Up to 50 kg) Feed Efficiency: A Meta-Regression Analysis

Currently, the NRC amino acid (AA) requirements for pigs published in 2012 are used as a reference in variable swine industries. However, recent results in several articles suggest that the standardized ileal digestible (SID) AA–lysine (Lys) ratio significantly evolved over the last two decades, while some publications report inconsistent outcomes. Therefore, the present study used a meta-regression analysis to assess the relative ratio to lysine to maximize the feed efficiency of four essential amino acids (tryptophan, valine, isoleucine, and methionine) in pig diets. According to the PRISMA guidelines, articles examining the target AA requirement using a basal diet supplemented with varying levels of crystalline AA (tryptophan, valine, isoleucine, or methionine) were identified across Scopus, PubMed, and Science Direct. As a result, 23, 22, 16, and 9 articles using tryptophan, valine, isoleucine, and methionine were selected and categorized into experiments for inclusion in our meta-analysis. The results suggested that the requirements of tryptophan, valine, isoleucine, and methionine in our meta-regression analysis were superior to NRC recommendations, regardless of the regression models and the growth phases with significant RSQ values (RSQ ≈ 1). Also, the QUAD and CLP regression models emphasized higher requirements than the LP model for the great majority of amino acids and growth phases. The results of the QUAD and CLP models were selected as estimations of the amino acid requirements for pigs under challenged conditions, whereas the LP model was chosen to estimate the amino acid requirements of genetically improved pigs under a modern housing system. The results of this meta-regression analysis could be used to refresh the information on the NRC amino acids (AA) requirements for swine.

The Impact of Thermal Treatments up to 140 °C on Amino Acid Digestibility of Fish Meal in Rainbow Trout (Oncorhynchus mykiss)

Fish meal (FM) is an essential ingredient in fish feeds, but the thermal treatments used during its production might affect its nutrient availability. Therefore, an in vivo digestibility trial was conducted with three different thermal treated FM, at no heat treatment (control), 70, and 140 °C. A total of 216 rainbow trout (230 ± 6.0 g) were randomly assigned to 12 tanks, and feces samples were collected by stripping. FM was produced by lyophilizing mackerel. The lyophilized FM (94% DM) was then divided into three groups: FM Control, which was not exposed to thermal treatments, and FM 70 °C and FM 140 °C, which were exposed for 1 h to the respective temperatures of its descriptions. A conventional FM-based (FM with 64% CP produced at 110 °C) control diet was used as a basal diet. In the experimental groups, 30% of the basal diet was replaced by one of the tested FMs. No differences in apparent total tract digestibility (ATTD) were observed between FM Control and 70 °C. Protein ATTD of FM 140 °C as well as Arg ATTD were lower compared to FM Control and 70 °C. The same effect was observed for His and Asp ATTD. The current study showed that thermal treatment affects FM macronutrient and amino acid ATTD.

Co-fermentation with multiple-strains and cellulase enhances the nutritional quality of hot-pressed rapeseed meal by modifying its physicochemical properties

The thermal damage of proteins and the presence of anti-nutritional factors seriously affect the quality of hot-pressed rapeseed meal (RSM), thereby limiting its utilization in the feed and food industry. Previously, we developed a co-fermentation method with multi-strains and cellulase that can simultaneously degrade the protein and anti-nutrient components in hot-pressed RSM. This study aimed to evaluate the impact of fermentation on the physicochemical properties and nutritional value of hot-pressed RSM. After fermentation, the levels of neutral detergent fiber (NDF) and glucosinolate (GLS) in hot pressed RSM decreased by 41.47% and 77.30%, respectively, and the trichloroacetic acid-soluble protein (TASP) and lysine contents increased by 1007.62% and 65.25%, respectively. During the fermentation process, the extensive hydrolysis of rapeseed protein resulted in a 49.11% yield of peptides < 3K Da, and intensified the umami, saltiness, sweetness, and bitterness of fermented rapeseed meal (FRSM). Animal experiments demonstrated that co-fermentation effectively enhances the ileal digestibility of most amino acids in hot-pressed RSM, as well as the deposition of nitrogen and energy, thereby improving the growth of growing pigs. Overall, the co-fermentation with microbes and cellulase is an effective strategy for enhancing the quality of hot-pressed RSM.

Potential New Methods to Analyze Basal and Total Endogenous Protein Losses of Host and Bacterial Origin in Pigs

BackgroundCurrent systems for assessing protein quality such as the Digestible Indispensable Amino Acid Score correct apparent amino acid (AA) digestibility for basal endogenous protein losses (bEPL), ignoring the potential influence of the diet on these losses. However, the quantification of total endogenous protein losses (tEPL) poses a challenge. ObjectivesTo evaluate different methods for quantifying tEPL and bEPL, and to assess their potential in discriminating between tEPL originating from bacteria and host. MethodsUsing an incomplete Youden square design, 12 ileal cannulated pigs received 10 different protein sources, and a nitrogen-free (NF) diet. Ileal digesta were collected on days 6 and 7 of each 1-wk feeding period, to quantify endogenous protein losses (EPL) and analyze apparent ileal digestibility. Ileal EPL were estimated based on 1) 16S-+18S gene copy quantitative polymerase chain reaction, 2) diaminopimelic acid (DAPA)+18S, 3) differential AA profiles in digesta, EPL, and bacteria, equaling tEPL, and 4) an NF diet and 5) whey protein isolate (WPI), equaling bEPL. ResultsIleal bEPL based on the NF and WPI method correlated moderately highly (r = 0.69, P < 0.05), but the NF method probably underestimated bEPL. In pigs fed the WPI diet, EPL based on the WPI and AA profile method were highly correlated (r = 0.88, P < 0.01). Overall, tEPL based on the AA profile method were moderately correlated with the 16S+18S method (r = 0.58, P < 0.001), and DAPA+18S (r = 0.57, P < 0.001). Low correlations were observed between bacterial tEPL based on the AA profile method and 16S or DAPA. Host tEPL based on the AA profile method and 18S were weakly correlated (r = 0.39, P < 0.001). ConclusionsThe AA profile method seems the most appropriate method for tEPL quantification, whereas the WPI method is preferred for bEPL quantification. Despite challenges in distinguishing between bacterial and host EPL, it is evident that bacterial proteins substantially (on average 37%–83%, depending on method) contribute to the EPL.

Interactive effects of dietary energy levels with amino acid density on growth performance and optimal digestible Lys to energy ratio of male broiler chickens

A total of 2,400 day-old off-sex male Ross 308 chicks were used in a 4 × 3 factorial array (8 replicates with 25 birds per replicate) to determine the interactive effects of dietary metabolizable energy (ME) and amino acid (AA) densities on productive traits of broiler chickens reared to 42 d of age. The experimental factors were 4 ME levels (control, -50, -100, -150 kcal) and 3 digestible AA levels (control, +3.0 and +6.0%). Diets were fed for starter (0-10 d), grower (11-24 d), finisher (25-35 d), and withdrawal (36-42 d) phases, with consistent reduction of ME and increase in AA density for each phase. Overall, ME reduction did not compromise final body weight (BW; d 42). However, when ME was reduced by 50 kcal, only the diets with +6% AA density improved BW, resulting in an interaction between ME and AA levels (P < 0.05). Reducing ME and increasing AA densities independently increased total feed intake (P < 0.01). An interaction between ME and AA density on feed conversion ratio (FCR) was observed where increasing AA density at both +3.0 and +6.0% levels at control ME reduced FCR, but with reduced ME diets, FCR was reduced only at +6% AA density (P < 0.01). Quadratic broken line models estimated a digestible Lys to ME ratio (mg Lys/1,000 kcal ME) of 474 and 407 in starter and grower diets, respectively, to optimize both BW and FCR. However, in finisher phase a ratio of 363 could only be predicted for optimal FCR and in withdrawal a ratio of 349 to optimize BW. In summary, these results indicate that the interaction between ME and AA densities affects the productive traits of broiler chickens. Increasing AA density at control ME density improves FCR, while reduced ME diets require higher AA density to improve FCR. Quadratic broken line models suggest specific digestible Lys to ME ratios for optimizing BW and FCR across different phases of the production cycle.

Determination and Prediction of Amino Acid Digestibility in Rapeseed Cake for Growing-Finishing Pigs.

The experiment was conducted to determine the apparent or standardized ileal digestibility (AID or SID) of crude protein (CP) and amino acids (AA) in 10 rapeseed cake samples fed to pigs, and to construct predictive models for the SID of CP and AA based on the chemical composition of rapeseed cakes. Twenty-two cannulated pigs (initial body weight: 39.8 ± 1.2 kg) were assigned to two 11 × 3 incomplete Latin square designs, including an N-free diet and 10 diets containing rapeseed cake. Each experimental period included 5 days of adaptation and 2 days of ileal digesta collection. Titanium dioxide (TiO2) was added at 0.3% to all the diets as an indigestible marker for calculating the ileal CP and AA digestibility. The coefficients of variation (CV) of the content of crude fat (EE), crude fiber (CF), neutral detergent fiber (NDF), acid detergent fiber (ADF), and total glucosinolates (TGS) in 10 samples of rapeseed cake were greater than 10%. The standardized ileal digestibility (SID) of crude protein (CP), lysine (Lys), methionine (Met), threonine (Thr), and tryptophan (Trp) in rapeseed cake was 73.34% (61.49 to 81.12%), 63.01% (41.41 to 73.10%), 69.47% (50.55 to 88.16%), 79.61% (74.41 to 87.58%), and 94.43% (91.34 to 97.20%), respectively. The best prediction equations for SIDCP, SIDLys, and SIDVal were as follows: SIDCP = 90.124 - 0.54NDF (R2 = 0.58), SIDLys = 100.107 - 1.229NDF (R2 = 0.94), and SIDVal = 151.012 - 2.990TGS (R2 = 0.57). Overall, great variation exists among the 10 rapeseed cakes, and the NDF, TGS, and heating temperature can be used as the key predictors for the SID of CP and AA.

Effect of increasing supplementation of dietary glycine on growth performance, meat quality, liver characteristics, and intestinal health in broiler chickens raised under heat stress conditions

The current study aimed to investigate the effect of increasing supplementation of dietary glycine (Gly) on growth performance, meat quality, liver characteristics, and intestinal health in broiler chickens raised under heat stress (HS) conditions. A total of one thousand six hundred 25-d-old broiler chickens were randomly allotted to 1 of 5 dietary treatments with 8 replicates. Each replicate comprised 20 male and 20 female birds. A negative control (NC) diet was prepared to meet or exceed energy and nutrient requirement estimates, whereas a positive control (PC) diet was formulated to contain increasing concentrations of AMEn by 50 kcal/kg as well as those of digestible amino acids, total Ca, and available P by 10% compared with the respective concentrations in the NC diet. Three additional diets were prepared by supplementing the NC diet with 0.4, 0.8, or 1.6% Gly. All chickens were raised under cyclic HS conditions at 29°C ± 0.89°C for 10 h/d and 23°C ± 1.45°C for the remaining time over an 18-d feeding trial. Results indicated that broiler chickens fed the NC diet had a greater (P < 0.05) FCR than those fed the PC diet under HS conditions. Increasing supplementation of up to 1.6% Gly in diets decreased (linear, P < 0.001) FCR in broiler chickens. Increasing supplementation of dietary Gly tended to increase (linear, P = 0.070) water holding capacity in the breast meat. Increasing supplementation of dietary Gly decreased (linear, P < 0.05) serum aspartate aminotransferase concentrations and tended to decrease blood heterophil:lymphocyte (linear, P = 0.083) and liver malondialdehyde concentrations (quadratic, P = 0.084). A tendency for increased villus height (linear, P = 0.086) and a significant increase in villus height:crypt depth ratio and goblet cell numbers (linear, P < 0.05) were identified following increasing Gly supplementation. In conclusion, increasing supplementation of dietary Gly improved feed efficiency, meat quality, liver health, and intestinal morphology possibly by mitigating oxidative stress and stress response in broiler chickens raised under HS conditions.

Influence of varying branched-chain amino acid ratio in diets containing corn gluten meal, L-isoleucine, and L-valine on 0–21 d turkey poult performance, relative mTOR activation, and apparent ileal amino acid digestibility

Influence of varying branched-chain amino acid ratio in diets containing corn gluten meal, L-isoleucine, and L-valine on 0–21 d turkey poult performance, relative mTOR activation, and apparent ileal amino acid digestibility