In vitro digestion and fermentation characteristics of canola co-products simulate their digestion in the pig intestine

Development and application of a multi-step porcine in vitro system to evaluate feedstuffs and feed additives for their efficacy in nutrient digestion, digesta characteristics, and intestinal immune responses

In vitro model provides alternatives to the use of live animals in research. In pig nutrition, there has been a tremendous increase in in vivo research over the decades. Proper utilization of in vitro models could provide a screening tool to reduce the needs of in vivo studies, research duration, cost, and the use of animals and feeds. This study aimed to develop a multi-step porcine in vitro system to simulate nutrient digestion and intestinal epithelial immune responses affected by feedstuffs and feed additives. Seven feedstuffs (corn, corn distillers dried grains with solubles [corn DDGS], barley, wheat, soybean meal, soy protein concentrates, and Corynebacterium glutamicum cell mass [CGCM]), feed enzymes (xylanase and phytase), and supplemental amino acids (arginine, methionine, and tryptophan), were used in this in vitro evaluation for their efficacy on digestibility, digesta characteristics, and intestinal health compared with the results from previously published in vivo studies. All in vitro evaluations were triplicated. Data were analyzed using Mixed procedure of SAS9.4. Evaluations included (1) nutrient digestibility of feedstuffs, (2) the effects of feed enzymes, xylanase and phytase, on digestibility of feedstuffs and specific substrates, and (3) the effects of amino acids, arginine, tryptophan, and methionine, on anti-inflammatory, anti-oxidative, and anti-heat stress statuses showing their effects (P < 0.05) on the measured items. Differences in dry matter and crude protein digestibility among the feedstuffs as well as effects of xylanase and phytase were detected (P < 0.05), including xylo-oligosaccharide profiles and phosphorus release from phytate. Supplementation of arginine, tryptophan, and methionine modulated (P < 0.05) cellular inflammatory and oxidative stress responses. The use of this in vitro model allowed the use of 3 experimental replications providing sufficient statistical power at P < 0.05. This indicates in vitro models can have increased precision and consistency compared with in vivo animal studies.

Research note: Nutritive value of cold-pressed flaxseed meal for broiler chicken

A study was conducted to evaluate standardized ileal digestibility (SID) of amino acids (AA) and N-corrected apparent metabolizable energy (AMEn) values of cold pressed flaxseed meal (CPFM) for broilers. One hundred and twenty broiler chicks were divided into 20 groups of 6 birds/group and fed 2 diets in a completely randomized design (10 groups/diet) from 14 to 21 d of age. The diets were cornstarch-based containing CPFM or conventional soybean meal (SBM; reference feedstuff) as the sole protein source. A N-free diet fed in another study conducted in the same facility and at the same time that the current study was conducted was used to estimate basal endogenous AA losses, and to calculate gross energy retention by difference method. The CPFM had greater neutral detergent fiber and ether extract contents (21.40 vs. 8.18% and 20.4 vs. 2.47% as is, respectively), but lower CP (20.47 vs. 48.28% as is) than SBM. The SID values of all indispensable AA (except for Leu, Phe and Trp) for CPFM were lower (P < 0.05) than those for SBM. The apparent retention of gross energy (65.95 vs. 44.24%) and N (55.53 vs. 9.79%), and AMEn (2,699 vs. 2,491 kcal/kg) for CPFM were lower (P < 0.05) than those for SBM. In conclusion, CPFM can serve as alternative oilseed co-product feedstuff for poultry. However, the CPFM has lower SID of AA and AMEn values than SBM likely due to the greater fiber content in the former than in the latter.

Effect of extrusion on energy and nutrient digestibility of lentil-based diets containing either supplemental plant or animal protein fed to growing pigs

Non-food grade and excess lentil grain production may be included in swine feeds to provide starch and protein and reduce feed cost. Extrusion processing may increase energy and nutrient digestibility of lentil-based diets containing either supplemental plant or animal protein sources. Therefore, the apparent ileal digestibility (AID) of crude protein (CP) and amino acids (AA), apparent total tract digestibility (ATTD) of gross energy (GE), and digestible energy (DE) value of lentil-based diets were assessed in growing pigs. Two diets were formulated to provide 2.4 Mcal net energy (NE)/kg and 4.35 g standardized ileal digestible lysine/Mcal NE: (1) soybean meal (SBM) diet, containing 50% lentil, 31% wheat, and 12.8% SBM; and (2) fish meal (FM) diet, containing 40% lentil, 45% wheat, and 10% FM. Following mixing, each diet batch was divided into two parts: one part remained as mash, whereas the other part was extruded using a single-screw extruder (400 rpm, 250 kg/h). Eight ileal-cannulated barrows (32.3 ± 1.5 kg) were fed the four diets at 2.8 times maintenance DE requirement (110 kcal per kg of body weight0.75) for four 9-d periods in a double 4 × 4 Latin square to achieve 8 observations per diet. Data were analyzed as a 2 × 2 factorial arrangement including protein source, post-mixing processing, and their interaction as fixed effects. The lentil sample contained 32.3% starch, 24.4% CP, 9.3% total dietary fiber, and 1.7 mg/g of trypsin inhibitor activity on as is-basis. Interactions between dietary protein source and post-mixing processing were not observed. Feeding FM diets resulted in greater (P < 0.05) AID of dry matter (DM), GE, and most AA, and ATTD of CP, but lower apparent hindgut fermentation of DM and GE than SBM diets. Extrusion increased (P < 0.05) the ATTD of GE and DE value of diets. The AID of CP and AA was 3.2 and 4.7%-units greater (P < 0.05), respectively, for the extruded than mash diets. In conclusion, feeding FM diets resulted in greater ileal digestibility of DM, GE, and AA than SBM diets. Extrusion increased the AID of CP and most AA, and DE value of lentil-based diets containing either supplemental plant protein or animal-protein, indicating that extrusion can increase the energy and protein value of plant-based diets fed to pigs.

Dynamic changes of inulin utilization associated with longitudinal development of gut microbiota

Inulin is a typical kind of fermentable polysaccharide and has emerged as a promising dietary supplement due to its multiple health-promoting effects. This study aimed to unveil the dynamic change pattern of inulin utilizability as a fermentation substrate during gut microbiota development and illuminate its potential association with gut microbiota in Chinese Jinhua native pig models via longitudinal analyses. Herein, fresh feces were collected at one week pre- and post-weaning as well as 3rd month post-weaning, respectively. Targeted metabolomics and in vitro simulated fermentation revealed increasing concentrations of fecal short-chain fatty acids (SCFAs) and elevating utilizability of inulin as a fermentation substrate. Microbiomic analyses demonstrated the conspicuous longitudinal alteration in gut microbial composition and a significant rise in microbial community diversity during gut microbiota development. Furthermore, gut microbial functional analyses showed a remarkable increase in the relative abundances of carbohydrate metabolism pathways, including pentose phosphate pathway, galactose metabolism pathway, butanoate metabolism pathway as well as fructose and mannose metabolism pathway. Notably, relative abundances of bacterial genera Bifidobacterium, Roseburia, Faecalibacterium and Enterococcus displayed significantly positive correlations with the production of microbial fermentation-derived SCFAs. Collectively, these findings offer novel insights into understanding inulin utilizability variations from the perspective of gut microbiota development.

A comparative study on in vitro and in vivo stomach-small intestinal and large intestinal digestion of plant protein meals in growing pigs

This experiment evaluated the difference between computer-controlled simulated digestion and in vivo stomach-small intestinal or large intestinal digestion for growing pigs. Five diets including a corn-soybean meal basal diet and four experimental diets with rapeseed meal (RSM), cottonseed meal (CSM), sunflower meal (SFM), or peanut meal (PNM) were assigned to each group of five barrows installed terminal ileal cannula or distal cecal cannula in a 5 × 5 Latin square design. Ileal digesta and feces were collected for the determination of digestibility of dry matter (DM) and gross energy (GE) as well as digestible energy (DE) at terminal ileum and total tract. The large intestinal digestibility and DE were calculated by the difference between measurements obtained at the terminal ileum and those obtained from total tract. In vitro stomach-small intestinal digestibility and DE for diets and plant protein meals were determined by stomach-small intestinal digestion in a computer-controlled simulated digestion system (CCSDS). The in vitro large intestinal digestibility and DE of diets were determined in a CCSDS using ileal digesta and enzymes extracted from cecal digesta of pigs. The in vitro large intestinal digestibility and DE of four plant protein meals were determined by the difference between stomach-small intestinal and total tract digestion in the CCSDS. For the experimental diets, the in vitro ileal digestibility and DE were not different from corresponding in vivo values in basal diet and PNM diet, but greater than corresponding in vivo values for diets with RSM, CSM, and SFM (P < 0.05). No difference was observed between in vitro and in vivo large intestinal digestibility and DE in five diets. For the feed ingredients, the in vitro ileal digestibility and DE did not differ from corresponding in vivo ileal values in RSM and PNM but were greater than the in vivo ileal values in CSM and SFM (P < 0.05). The in vitro large intestinal GE digestibility and DE were not different from in vivo large intestinal values in RSM, CSM, and PNM, but lower than in vivo large intestinal values in SFM. This finding may relate to the higher fiber content of plant protein meals resulting in shorter digestion time of in vivo stomach-small intestine thus lower digestibility compared to in vitro, indicating it is necessary to optimize in vitro stomach-small intestinal digestion time.

Sorghum tannin extract impedes in vitro digestibility and fermentability of nutrients in the simulated porcine gastrointestinal tract

The site and extent of digestion of sorghum nutrients affected by tannins in the intestine are not clarified. Porcine small intestine digestion and large intestine fermentation were simulated in vitro to determine the effects of sorghum tannin extract on the digestion and fermentation characteristics of nutrients in the mimicked porcine gastrointestinal tract. In experiment 1, low-tannin sorghum grain without or with 30 mg/g sorghum tannin extract were digested by porcine pepsin and pancreatin to measure in vitro digestibility of nutrients. In experiment 2, the lyophilized porcine ileal digesta from 3 barrows (Duroc × Landrace × Yorkshire, 27.75 ± 1.46 kg) fed the low-tannin sorghum grain without or with 30 mg/g sorghum tannin extract and the undigested residues from experiment 1 were, individually, incubated with fresh pig cecal digesta as inoculums for 48 h to simulate the porcine hindgut fermentation. The results revealed that sorghum tannin extract decreased in vitro digestibility of nutrients both by pepsin hydrolysis or pepsin-pancreatin hydrolysis (P < 0.05). Although enzymatically unhydrolyzed residues provided more energy (P = 0.09) and nitrogen (P < 0.05) as fermentation substrates, the microbial degradation of nutrients from unhydrolyzed residues and porcine ileal digesta were both decreased by sorghum tannin extract (P < 0.05). Regardless of unhydrolyzed residues or ileal digesta as fermentation substrates, microbial metabolites including the accumulative gas production excluding the first 6 h, total short-chain fatty acid and microbial protein content in the fermented solutions were decreased (P < 0.05). The relative abundances of Lachnospiraceae AC2044 and NK4A136 and Ruminococcus_1 was decreased by sorghum tannin extract (P < 0.05). In conclusion, sorghum tannin extract not only directly decreased the chemical enzymatic digestion of nutrients in the simulated anterior intestine, but also directly inhibited the microbial fermentation including microbial diversities and metabolites in the simulated posterior intestine of pigs. The experiment implies that the decreased abundances of Lachnospiraceae and Ruminococcaceae by tannins in the hindgut may weaken the fermentation capacity of microflora and thus impair the nutrient digestion in the hindgut, and ultimately reduce the total tract digestibility of nutrients in pigs fed high tannin sorghum.

Comparative digestion and fermentation characteristics of low-tannin or high-tannin sorghum grain in the porcine gastrointestinal tract

High-tannin sorghum grain (HTS) has been previously proved to contain lower apparent total tract digestibility (ATTD) of nutrients than low-tannin sorghum grain (LTS) for pigs. This study was conducted to identify in which segments (foregut or hindgut) of the intestinal tract of pigs the digestion of nutrients was mostly influenced, and to compare the digestion and fermentation characteristics of LTS and HTS in the porcine gastrointestinal tract. In experiment 1, HTS and LTS were digested by porcine pepsin and pancreatin to simulate small intestine digestion, and subsequently the undigested residues were incubated with fresh pig cecal digesta as inoculums for 48 h to simulate the porcine large intestine fermentation in vitro. The results revealed that the in vitro digestibility of air-dry matter, gross energy (GE), and crude protein (CP) was lower (P < 0.05) in HTS than that in LTS, regardless of the simulated small intestine digestion or large intestine fermentation. The enzymatically unhydrolyzed residue of HTS decreased the accumulative gas production excluding the first 3 h and the short-chain fatty acid concentration including acetic acid, propionic acid, and butyric acid in the fermented solutions (P < 0.05), although it provided more nutrients as fermentation substrates (P < 0.05). In experiment 2, 12 crossbred barrows (25.5 ± 2.5 kg body weight) with a T-cannula inserted in the distal ileum were randomly allotted to two diets (N = 6) to determine nutrient digestibility in the foregut (AID, apparent ileal digestibility) and in the hindgut of pigs (HGD, hindgut disappearance). The study lasted 10 d, with a 5 d adaption to the diets followed by a 3 d collection of feces and then a 2 d collection of ileal digesta. Diets included 96.6% HTS or LTS as the only source of dietary energy and nitrogen. The AID and ATTD of dry matter, GE, and CP in HTS were lower than those in LTS (P < 0.05). There was no difference in HGD of nutrients between LTS and HTS. Eight out of fifteen amino acids in HTS had lower AID values (P < 0.05). In conclusion, HTS provided lower small intestine digestibility of nutrients and lower large intestine fermentation parameters, implying that condensed tannins in sorghum grain may impede the nutrient digestibility in the foregut and limit the fermentability in the hindgut segment of pigs. Hence, digestion and fermentation characteristics of sorghum grain may vary depending on the condensed tannins.

Starchy and fibrous feedstuffs differ in their in vitro digestibility and fermentation characteristics and differently modulate gut microbiota of swine

Background

Alternative feedstuffs may contribute to reducing feed costs of pig production. But these feedstuffs are typically rich in fiber and resistant starch (RS). Dietary fibers and RS are fermented in the gastrointestinal tract (GIT) and modulate the microbial community. Certain microbes in the GIT can promote host health, depending on the type of fermentation substrates available. In this study, six alternative feedstuffs (three starchy: Okinawan sweet potato, OSP; yam, and taro, and three fibrous: wheat millrun, WMR; barley brewers grain, BBG; and macadamia nut cake, MNC) were evaluated for their in vitro digestibility and fermentation characteristics and their effects on pig’s hindgut microbial profile. After 2 steps of enzymatic digestion assay, residues were fermented using fresh pig feces as microbial inoculum, and gas production was recorded periodically for 72 h and modeled for fermentation kinetics. After fermentation, the residual liquid phase was analyzed for short-chain fatty acid (SCFA), and the solid phase was used to determine the nutrient’s digestibility and microbial community.

Results

In vitro ileal digestibility of dry matter and gross energy was higher in starchy than fibrous feedstuffs. Total gas and SCFA production were significantly higher (P < 0.001) in starchy feedstuffs than fibrous feedstuffs. Both acetate and propionate production was significantly higher (P < 0.001) in all starchy feedstuffs than BBG and MNC; WMR was in between. Overall alpha diversity was not significantly different within and between starchy and fibrous feedstuffs. Beta diversity (measured using bray Curtis dissimilarity distance) of starchy feedstuffs was significantly different (P < 0.005) than fibrous feedstuffs.

Conclusion

Starchy feedstuffs acted as a substrate to similar types of microbes, whereas fibrous feedstuffs resulted in a more diverse microbial population. Such alternative feedstuffs may exert comparable beneficial effects, thus may be included in swine diets to improve gut health.

Effects of treating Prosopis juliflora pods with multienzyme, with and without bacterial cultures on in vitro dry matter digestibility (IVDMD), fermentation kinetics, and performance of growing pigs

This study was conducted to determine the effects of treating Prosopis juliflora pods with multienzyme and bacterial cultures on in vitro dry matter digestibility (IVDMD), fermentation kinetics, and performance of growing pigs. Experiment one consisted of a pepsin-pancreatine hydrolysis method to simulate, in vitro, the pig digestive system and was followed by in vitro gas production to assess fermentation kinetics. Samples of ground Prosopis pod meal (GPPM) were allocated to four treatments with three replicates each. Treatments included GPPM treated with multienzyme (Natuzyme®) (T1); untreated (GPPM) (T2); GPPM fermented with (Lactobacillus plantarum MTD1 Ecosyl ®) (T3), and GPPM treated using natural fermentation (T4). The second experiment assessed the performance of pigs fed the best treatment from experiment 1. Thirty Landrace × large white crosses of 20 ± 2 kg were allotted to five treatments with six pigs each (replicates). The dietary treatments were PC, 0% GPPM + enzyme; NC, 0% GPPM and 0% enzyme; D1, 10% GPPM + enzyme; D2, 20% GPPM + enzyme; and D3, 30% GPPM + enzyme. A randomized complete block design was used for both experiments. Enzyme treatment (T1) and T3 improved the IVDMD of the GPPM compared to T2 by 3.68% and 1.2%, respectively (p < 0.05). Cumulative gas was highest and Tmax lowest for T1 but significantly different only to T4 (p < 0.05). Average daily gain and intake were highest for pigs fed GPPM up to 10% (PC, D1). Feed conversion ratio increased with the level of GPPM in the diet. The results suggest Prosopis juliflora pods treated with enzymes can be added in pig diets up to 30%.

Accuracy of predicting metabolizable energy from in vitro digestible energy determined with a computer-controlled simulated digestion system in feed ingredients for ducks

Two experiments were conducted to study the accuracy of predicting true metabolizable energy (TME) of ingredients for ducks from in vitro digestible energy (IVDE) determined with a computer-controlled simulated digestion system. Experiment 1 was to establish TME prediction models from the IVDE of 9 energy feed ingredients and 12 protein feed ingredients using regression analysis. Experiment 2 was to validate the accuracy of the predicted ME of 10 ingredients randomly selected from Exp. 1. Ten diets were formulated with 2 to 6 of 10 ingredients. Dietary in vivo TME values were compared with calculated values based on the TME predicted in Exp. 1. In Exp. 1, the correlation coefficients between TME and IVDE were 0.9339 (P < 0.05) in 9 energy feed ingredients and 0.8332 (P < 0.05) in 12 protein feed ingredients. No significant difference was observed on the slope and intercept of TME regression models between 9 energy feed ingredients and 12 protein feed ingredients. Therefore, the regression model of TME on IVDE for 21 feed ingredients was TME = 0.7169 × IVDE +1,224 (R² = 0.7542, P < 0.01). Determined and predicted TME differed by less than 100 kcal/kg of DM in 11 ingredients, and the difference ranged from 100 to 200 kcal/kg of DM in 5 ingredients. However, the difference between determined and predicted TME varied from 410 to 625 kcal/kg of DM in rice bran, rapeseed meal, corn gluten meal, and citric acid meal. In Exp. 2, the determined and calculated TME were comparable (3,631 vs. 3,639 kcal/kg of DM) and highly correlated (r = 0.9014; P < 0.05) in 10 diets. Determined and calculated TME differed by less than 100 kcal/kg of DM in 7 diets and by 106 to 133 kcal/kg of DM in 3 diets. These results have demonstrated that TME can be accurately predicted from IVDE in most feed ingredients, but it is less accurate for rice bran, rapeseed meal, corn gluten and citric acid meal.

Growth performance and gut health of Escherichia coli-challenged weaned pigs fed canola meal-containing diet

An experiment was conducted to evaluate the effects of including canola meal (CM) in diets for weaning pigs challenged with a F18 strain of Escherichia coli on growth performance and gut health. A total of 36 individually housed weaned pigs (initial body weight [BW] = 6.22 kg) were randomly allotted to one of the three diets (12 pigs/diet). The three diets were corn-soybean meal (SBM)-based basal diet (control diet) and the basal diet with 0.3% zinc oxide, 0.2% chlortetracycline, and 0.2% tiamulin (antibiotic diet) or with 20% CM diet. The diets were fed in two phases: Phase 1: days 0 to 7 and Phase 2: days 7 to 20. All pigs were given an oral dose of 2 × 109 CFU of F18 strain of E. coli on day 7. Fecal score was assessed daily throughout the trial. Dietary antibiotics increased (P < 0.05) overall average daily gain (ADG) and average daily feed intake (ADFI) compared by 48% and 47%, respectively. Dietary CM increased (P < 0.05) overall ADG and ADFI by 22% and 23%, respectively; but the ADG and ADFI values for CM-containing diet did not reach those for the antibiotics-containing diet. Dietary antibiotics reduced (P < 0.05) fecal score; however, dietary CM unaffected fecal score. Dietary antibiotics decreased (P < 0.05) liver weight per unit live BW by 16% at day 20, whereas dietary CM did not affect liver weight per unit live BW (29.2 vs. 28.6). Also, dietary antibiotics increased (P < 0.05) serum triiodothyronine and tetraiodothyronine levels for day 14, whereas dietary CM did not affect the serum level of these hormones. Dietary antibiotics reduced (P < 0.05) the number white blood cells and neutrophils by 38% and 43% at day 20, respectively, whereas dietary CM tended to reduce (P = 0.09) the number white blood cells by 19% at day 20. The number white blood cells for CM diet tended to be greater (P < 0.10) than that for antibiotics diet. The dietary antibiotics decreased (P < 0.05) the concentration of individual volatile fatty acids and hence of total volatile fatty acid in cecum by 61% at day 20, whereas dietary CM decreased (P < 0.05) cecal butyric acid concentration by 61% and tended to reduce (P < 0.10) total volatile fatty acid concentration by 30% at day 20. In conclusion, the dietary inclusion of 20% CM improved ADG and tended to reduce white blood cell counts. Thus, inclusion of CM in antibiotics-free corn-SBM-based diets for weaned pigs that are challenged with F18 strain of E. coli can result in their improved performance partly through a reduction of the inflammatory response.

Effect of feeding acidified or fermented barley using Limosilactobacillus reuteri with or without supplemental phytase on diet nutrient digestibility in growing pigs

Fermentation of cereal grains may degrade myo-inositol 1,2,3,4,5,6-hexakis (dihydrogen phosphate) (InsP6) thereby increasing nutrient digestibility. Effects of chemical acidification or fermentation with Limosilactobacillus (L.) reuteri with or without phytase of high β-glucan hull-less barley grain on apparent ileal digestibility (AID) and apparent total tract digestibility (ATTD) of nutrients and gross energy (GE), standardized ileal digestibility (SID) of crude protein (CP) and amino acids (AAs), and standardized total tract digestibility (STTD) of P were assessed in growing pigs. Pigs were fed four mash barley-based diets balanced for water content: 1) unfermented barley (Control); 2) chemically acidified barley (ACD) with lactic acid and acidic acid (0.019 L/kg barley grain at a ratio of 4:1 [vol/vol]); 3) barley fermented with L. reuteri TMW 1.656 (Fermented without phytase); and 4) barley fermented with L. reuteri TMW 1.656 and phytase (Fermented with phytase; 500 FYT/kg barley grain). The acidification and fermentation treatments occurred for 24 h at 37 °C in a water bath. The four diets were fed to eight ileal-cannulated barrows (initial body weight [BW], 17.4 kg) for four 11-d periods in a double 4 × 4 Latin square. Barley grain InsP6 content of Control, ACD, Fermented without phytase, or Fermented with phytase was 1.12%, 0.59%, 0.52% dry matter (DM), or not detectable, respectively. Diet ATTD of DM, CP, Ca, and GE, digestible energy (DE), predicted net energy (NE) value, and urinary excretion of P were greater (P < 0.05) for ACD than Control. Diet ATTD of DM, CP, Ca, GE, DE and predicted NE value, urinary excretion of P was greater (P < 0.05), and diet AID of Ca and ATTD and STTD of P tended to be greater (P < 0.10) for Fermented without phytase than Control. Diet ATTD of GE was lower (P < 0.05) and diet ATTD and STTD of P, AID and ATTD of Ca was greater (P < 0.05) for Fermented with phytase than Fermented without phytase. Acidification or fermentation with/without phytase did not affect diet SID of CP and AA. In conclusion, ACD or Fermented without phytase partially degraded InsP6 in barley grain and increased diet ATTD of DM, CP, and GE, but not SID of CP and most AA in growing pigs. Fermentation with phytase entirely degraded InsP6 in barley grain and maximized P and Ca digestibility, thereby reducing the need to provide inorganic dietary P to meet P requirements of growing pigs.

Nutrient digestibility of extruded canola meal in ileal-cannulated growing pigs and effects of its feeding on diet nutrient digestibility and growth performance in weaned pigs

Canola meal (CM) contains less crude protein (CP) and more fiber and anti-nutritional factors such as glucosinolates than soybean meal (SBM) and consequently has a lower nutrient digestibility. Therefore, processing strategies that may increase the feeding value of CM warrant study. In two experiments, the effects of extrusion of Brassica napus CM on apparent (AID) and standardized ileal digestibility (SID) of amino acids (AA), apparent total tract digestibility (ATTD) of gross energy (GE) in growing pigs, and growth performance and diet digestibility in weaned pigs were assessed. Solvent-extracted CM was extruded using a single-screw extruder at three screw speeds: 250 (CM-250), 350 (CM-350), or 450 (CM-450) rpm. In exp. 1, in a double 4 × 4 Latin square, eight ileal-cannulated barrows (initial body weight [BW], 68.1 kg) were fed corn starch-based diets containing 50% CM or extruded CM. The CM sample contained 43.2% CP, 33.2% total dietary fiber (TDF), and 8.9 µmol of total glucosinolates/g on a dry matter (DM) basis. Extrusion increased (P < 0.05) the AID of CP, reduced (P < 0.05) apparent hindgut fermentation of CP, and decreased (P < 0.05) predicted net energy (NE) value of diets. Extrusion increased diet AID and CM SID of most indispensable AA by 3.1 to 5.3%-units. In exp. 2, 200 weaned pigs (initial BW, 8.3 kg) were fed diets containing 20% SBM, CM, or extruded CM starting 2 wk postweaning for 3 wk. The CM sample contained 42.7% CP, 28.3% TDF, and 5.3 µmol total glucosinolates/g DM. Wheat-based diets provided 2.3 Mcal NE/kg and 5.1 g SID Lys/Mcal NE. Dietary inclusion of extruded CM replacing SBM decreased (P < 0.05) diet ATTD of DM, GE and CP, and DE value. Average daily feed intake, average daily gain (ADG), and gain:feed (G:F) of pigs did not differ between extruded CM and SBM diets and were not affected by extrusion, but increasing extruder screw speed linearly increased (P < 0.05) ADG for day 1 to 7 and G:F for the entire trial. In conclusion, extrusion increased diet AID and CM SID of AA but not DE and predicted NE values of CM. However, increasing extruder speed did not further increase the SID of most of the AA of CM in growing pigs. Dietary inclusion of 20% CM or extruded CM did not affect the growth performance in weaned pigs.

Trends in feed evaluation for poultry with emphasis on in vitro techniques

Accurate knowledge of the actual nutritional value of individual feed ingredients and complete diets is critical for efficient and sustainable animal production. For this reason, feed evaluation has always been in the forefront of nutritional research. Feed evaluation for poultry involves several approaches that include chemical analysis, table values, prediction equations, near-infrared reflectance spectroscopy, in vivo data and in vitro digestion techniques. Among these, the use of animals (in vivo) is the most valuable to gain information on nutrient utilization and is more predictive of bird performance. However, in vivo methods are expensive, laborious and time-consuming. It is therefore important to establish in vitro methods that are reliable, rapid and practical to assess the nutritional quality of feed ingredients or complete diets. Accuracy of the technique is crucial, as poor prediction will have a negative impact on bird performance and, increase feed cost and environmental issues. In this review, the relevance and importance of feed evaluation in poultry nutrition will be highlighted and the various approaches to evaluate the feed value of feed ingredients or complete diets will be discussed. Trends in and practical limitations encountered in feed evaluation science, with emphasis on in vitro digestion techniques, will be discussed.

Toxicity of Canola-Derived Glucosinolate Degradation Products in Pigs-A Review

Canola co-products are widely included in swine diets as sources of proteins. However, inclusion of canola co-products in diets for pigs is limited by toxicity of glucosinolate degradation products. Aliphatic and aromatic glucosinolates are two major classes of glucosinolates. Glucosinolate degradation products derived from aliphatic glucosinolates (progoitrin) include crambene, epithionitriles, and goitrin, whereas indole-3-acetonitrile, thiocyanate, and indole-3-carbinol are the major aromatic glucosinolates (glucobrassicin)-derived degradation products. At acidic pH (<5.7), progoitrin is degraded by myrosinases to crambene and epithionitriles in the presence of iron, regardless of the presence of epithiospecifier protein (ESP), whereas progoitrin is degraded by myrosinases to goitrin in the absence of ESP, regardless of the presence of iron at neutral pH (6.5). Indole-3-acetonitrile is the major degradation product derived from glucobrassicin in the absence of ESP, regardless of the presence of iron at acidic pH (<4.0), whereas thiocyanate and indole-3-carbinol are the major glucobrassicin-derived degradation products in the absence of ESP, regardless of the presence of iron at neutral pH (7.0). In conclusion, the composition of glucosinolate degradation products is affected by parent glucosinolate composition and hindgut pH. Thus, toxicity of canola co-product-derived glucosinolates can be potentially alleviated by modifying the hindgut pH of pigs.

Canola meal in nursery pig diets: growth performance and gut health

An experiment was conducted to determine the effects of including canola meal (CM) in nursery pig diets on growth performance, immune response, fecal microbial composition, and gut integrity. A total of 200 nursery pigs (initial body weight = 7.00 kg) were obtained in two batches of 100 pigs each. Pigs in each batch were housed in 25 pens (four pigs per pen) and fed five diets in a randomized complete block design. The five diets were corn-soybean meal (SBM)-based basal diets with 0%, 10%, 20%, 30%, or 40% of CM. The diets were fed in three phases: phase 1: day 0 to 7, phase 2: day 7 to 21, and phase 3: day 21 to 42. Diets in each phase were formulated to similar net energy, Ca, and digestible P and amino acid contents. Feed intake and body weight were measured by phase. Immune response and gut integrity parameters were measured at the end of phases 1 and 2. Fecal microbial composition for diets with 0% or 20% CM was determined at the end of phase 2. Overall average daily gain (ADG) responded quadratically (P < 0.05) to increasing dietary level of CM such that ADG was increased by 17% due to an increase in the dietary level of CM from 0% to 20% and was reduced by 16% due to an increase in the dietary level of CM from 20% to 40%. Pigs fed diets with 0% or 40% CM did not differ in overall ADG. Dietary CM tended to quadratically decrease (P = 0.09) serum immunoglobulin A (IgA) level at the end of phase 2 such that serum IgA level tended to reduce with an increase in dietary CM from 0% to 20% and to increase with an increase in dietary CM from 20% to 40%. Dietary CM at 20% decreased (P < 0.05) the relative abundance of Bacteroidetes phylum and tended to increase (P = 0.07) the relative abundance of Firmicutes phylum. Dietary CM linearly increased (P < 0.05) the lactulose to mannitol ratio in the urine by 47% and 49% at the end of phases 1 and 2, respectively, and tended to linearly decrease (P < 0.10) ileal transepithelial electrical resistance at the end of phase 1 by 64%. In conclusion, CM fed in the current study could be included in corn-SBM-based diets for nursery pigs 20% to improve the growth performance and gut microbial composition and reduce immune response. Also, the CM used in the current study could be included in corn-SBM-based diets for nursery pigs at 30% or 40% without compromising growth performance. Dietary CM increased gut permeability, implying that dietary CM at 20% improves the growth performance of weaned pigs through mechanisms other than reducing gut permeability.

Soybean meal allergenic protein degradation and gut health of piglets fed protease-supplemented diets

Two experiments were conducted to determine the effects of protease supplementation on degradation of soybean meal (SBM) allergenic proteins (glycinin and β-conglycinin) and gut health of weaned pigs fed soybean meal-based diets. In experiment 1, 2 SBM samples from 2 different sources were subjected to porcine in vitro gastric degradation to determine the effects of protease (at 15,000 U/kg of feedstuff) on degradation of the soybean allergenic proteins. In experiment 2, 48 weaned pigs (body weight = 6.66 kg) were obtained in 2 batches of 24 pigs each. Pigs were individually housed in metabolic crates and fed 4 diets (12 pigs/diet). The diets were corn-based diet with SBM 1 or SBM 2 without or with protease at 15,000 U/kg of diet in 2 × 2 factorial arrangement. Diets were fed for 10 d and pigs were sacrificed on day 10 for measurement of small intestinal histomorphology, permeability of small intestine mounted in Ussing chambers, and serum concentration of pro-inflammatory cytokines. Two SBM sources (SBM 1 and SBM 2) contained 46.9% or 47.7% CP, 14.0% or 14.6% glycinin, and 9.90% or 10.3% β-conglycinin, respectively. Protease and SBM source did not interact on any of the response criteria measured in the current study. Protease supplementation tended to increase (P = 0.069) the in vitro gastric degradation of glycinin. Protease supplementation tended to reduce (P = 0.099) fluorescein isothiocyanate dextran 4,000 Da (which is a marker probe for intestinal permeability) flow in jejunum, and reduced (P = 0.037) serum TNF-α concentration. Protease did not affect small intestinal histomorphology. In conclusion, protease tended to increase gastric degradation of glycinin and reduce gut permeability, and serum concentration of pro-inflammatory cytokines, indicating that the protease used in the current study can be added to SBM-based diets for weanling pigs to improve gut health.

Growth performance and gut health of Escherichia coli-challenged weaned pigs fed diets supplemented with a Bacillus subtilis direct-fed microbial

This study was conducted to investigate the effects of a direct-fed microbial (DFM) product (Bacillus subtilis strain DSM 32540) in weaned pigs challenged with K88 strain of Escherichia coli on growth performance and indicators of gut health. A total of 21 weaned pigs [initial body weight (BW) = 8.19 kg] were housed individually in pens and fed three diets (seven replicates per diet) for 21 d in a completely randomized design. The three diets were a corn-soybean meal-based basal diet without feed additives, a basal diet with 0.25% antibiotics (neo-Oxy 10-10; neomycin + oxytetracycline), or a basal diet with 0.05% DFM. All pigs were orally challenged with a subclinical dose (6.7 × 10⁸ CFU/mL) of K88 strain of E. coli on day 3 of the study (3 d after weaning). Feed intake and BW data were collected on days 0, 3, 7, 14, and 21. Fecal scores were recorded daily. On day 21, pigs were sacrificed to determine various indicators of gut health. Supplementation of the basal diet with antibiotics or DFM did not affect the overall (days 0-21) growth performance of pigs. However, antibiotics or DFM supplementation increased (P = 0.010) gain:feed (G:F) of pigs during the post-E. coli challenge period (days 3-21) by 23% and 24%, respectively. The G:F for the DFM-supplemented diet did not differ from that for the antibiotics-supplemented diet. The frequency of diarrhea for pigs fed a diet with antibiotics or DFM tended to be lower (P = 0.071) than that of pigs fed the basal diet. The jejunal villous height (VH) and the VH to crypt depth ratio (VH:CD) were increased (P < 0.001) by 33% and 35%, respectively, due to the inclusion of antibiotics in the basal diet and by 43% and 41%, respectively due to the inclusion of DFM in the basal diet. The VH and VH:CD for the DFM-supplemented diet were greater (P < 0.05) than those for the antibiotics-supplemented diet. Ileal VH was increased (P < 0.05) by 46% due to the inclusion of DFM in the basal diet. The empty weight of small intestine, cecum, or colon relative to live BW was unaffected by dietary antibiotics or DFM supplementation. In conclusion, the addition of DFM to the basal diet improved the feed efficiency of E. coli-challenged weaned pigs to a value similar to that of the antibiotics-supplemented diet and increased jejunal VH and VH:CD ratio to values greater than those for the antibiotics-supplemented diet. Thus, under E. coli challenge, the test DFM product may replace the use of antibiotics as a growth promoter in diets for weaned pigs to improve feed efficiency and gut integrity.

Effect of Dietary Fiber Sources on In-Vitro Fermentation and Microbiota in Monogastrics

Feed fiber composition is usually considered as one of the factors that have an impact on digestive tract microbiota composition. The investigations on the level of fermentation and in-vitro digestibility of different fibers are not well understood. The aim of the current study is to determine the effect of different fiber sources on intestinal nutrient digestibility, hindgut fermentation, and microbial community composition under in vitro conditions using pigs' hindgut as a model. The experimental treatment diets contained alfalfa hay, cornstalk, and rice straw. Cornstalk treatment displayed higher digestibility compared to alfalfa hay and rice straw; similar results were observed with in-vitro digestibility using intestinal digesta. Firmicutes were the most abundant phyla (Firmicutes = 89.2%), and Lactobacillus were the prominent genera (75.2%) in response to alfalfa compared to rice straw and cornstalk treatments. In simulated in-vitro digestion, corn stalk fiber improved dry matter digestibility; rice straw fiber improved volatile fatty acid content and fermentation efficiency. Alfalfa fiber improved the thickness of deposited Firmicutes and Lactobacillus.

In Vitro Fermentation and Chemical Characteristics of Mediterranean By-Products for Swine Nutrition

Simple Summary

By-products are residues obtained from agriculture and/or industrial processes, considered as wastes that could be used in animal nutrition. They are considered valid instruments to reduce feeding costs and breeding environmental impact. These residues may contain beneficial molecules that could be naturally transferred to animal products. In this study, the nutritional characteristics of eight by-products derived from citrus fruit juice (three pulps and two molasses) and olive oil (three olive cake) processes are evaluated for their possible use in pig diets. The chemical composition and fermentation parameters are different when comparing the citrus fruits and olive oil by-products. The citrus by-products are rich in fermentable carbohydrates, while olive oil by-products are rich in un-fermentable carbohydrates and fat. In any case, all the by-products categories show interesting nutritional characteristics. By-products typical of the Mediterranean area could be use in pig nutrition and could be considered an effective system to reduce animal production costs and limit the environmental impact of some production systems.

Abstract

The purpose of the study is to determine the nutritional characteristics of some by-products derived from fruit juice and olive oil production to evaluate their use in pig nutrition. Five by-products of citrus fruit (three citrus fruit pulp and two molasses) and three by-products of olive oil (olive cake) obtained by different varieties are analysed for chemical composition. The fermentation characteristics are evaluated in vitro using the gas production technique with swine faecal inoculum. All the citrus by-products are highly fermentable, producing gas and a high amount of short-chain fatty acids. The fermentation kinetics vary when comparing pulps and molasses. Citrus fruit pulps show lower and slower fermentation rates than molasses. The olive oil by-products, compared to citrus fruits ones, are richer in NDF and ADL. These characteristics negatively affect all the fermentation parameters. Therefore, the high concentration of fiber and lipids represents a key aspect in the nutrition of fattening pigs. The preliminary results obtained in this study confirm that the use of by-products in pig nutrition could represent a valid opportunity the reduce the livestock economic cost and environmental impact.

Enhancing the Nutritive Value of Corn Whole Stillage for Pigs via Pretreatment and Predigestion

Corn DDGS is poorly digested by pigs. Pretreatment or predigestion of whole stillage (WS; slurry material from which DDGS is derived) can potentially improve corn DDGS digestibility. Thus, a study was conducted to determine the effects of pretreating WS with heat (160 °C and 70 psi for 20 min) alone or in combination with citric acid (10 g/L; CA), sulfuric acid (90 mM; H₂SO₄), or ammonia (1%), without or with subsequent multienzymatic hydrolysis for 24 h, on porcine digestibility. Dried untreated, heat-pretreated, CA-pretreated, H₂SO₄-pretreated, and ammonia-pretreated WS contained 23, 21, 12 19, and 18% total nonstarch polysaccharides, respectively. Pretreatment increased in vitro digestibility of dry matter of WS by ∼11 (CA) to ∼15% units (ammonia). Multienzyme hydrolysis increased in vitro digestibility of dry matter of WS by ∼6 (ammonia-treated WS) to ∼18% units (untreated WS). Thus, pretreatment or predigestion can improve the digestibility of WS and hence the resulting DDGS.

Nutritive value of multienzyme supplemented cold-pressed camelina cake for pigs

Cold-pressed camelina cake (CPCC) is a fibrous co-product of camelina seed pressing and available for livestock feeding. However, information is lacking on the effect of supplementing fiber-degrading enzymes to CPCC-based diets on nutrient utilization by pigs. Experiment 1 determined the effect of multienzyme supplementation on standardized ileal digestibility (SID) of amino acid (AA) and net energy (NE) value of CPCC for pigs. Six ileal-cannulated barrows (average initial body weight [BW] = 36 kg) were fed five diets in 5 × 5 Latin square design with 1 added column to give six replicates per diet. The diets were a corn-soybean meal (SBM)-soybean oil-based diet and the basal diet with corn, SBM, and soybean oil replaced by 25% CPCC with or without multienzyme (600 U of xylanase, 75 U of glucanase, 250 U of cellulose, 30 U of mannanase, 350 U of invertase, 2,500 U of protease, and 6,000 U of amylase/kg of diet; Superzyme-CS, 0.5 g/kg) in a 2 × 2 factorial arrangement. The fifth diet was a low-casein cornstarch-based diet. The ratio of corn to SBM and soybean oil in the basal diet was identical to the CCPC-containing diets to allow calculation of nutrient digestibility of CPCC by the difference method. On a dry matter (DM) basis, CPCC contained 42% crude protein, 10.5% ether extract, 25.4% neutral detergent fiber (NDF), 2.07% Lys, 0.73% Met, 1.64% Thr, 0.51% Trp, and 22.1 trypsin inhibitor units per milligram, respectively. The SID of Lys, Met, Thr, and Trp for CPCC were 43.5%, 70.7%, 44.8%, and 55.3%, respectively. The digestible energy (DE) and NE values for CPCC were 3,663 and 2,209 kcal/kg of DM, respectively. Multienzyme supplementation did not affect the SID of AA, and DE and NE values for the corn-SBM-CPCC-based diet, and for the CPCC. In experiment 2, the effects of multienzyme dosage (0.5 or 50 g/kg of treated feedstuff) on porcine in vitro digestibility of DM (IVDDM) of CPCC was determined. The IVDDM of CPCC was increased (P < 0.001) with an increase in multienzyme dosage. Multienzyme at 0.5 g/kg did not affect IVDDM of CPCC. However, multienzyme at 50 g/kg increased (P < 0.01) IVDDM for CPCC by at least 16%. In conclusion, multienzyme at 0.5 g/kg did not affect SID of AA and NE values, and IVDDM for CPCC. However, multienzyme at 50 g/kg improved IVDDM of CPCC, implying that the efficacy of the multienzyme with regard to improving nutrient digestibility of CPCC in pigs is dosage dependent.

Effects of dietary inclusion of macaúba seed cake meal on performance, caecotrophy traits and in vitro evaluations for growing rabbits

The objective was to evaluate the inclusion of macaúba seed cake (MSC) meal in diets for growing rabbits by assessing their growth and slaughtering performance, haematological traits, nutritional contribution of caecotrophs, in vitro digestibility, degradability and fermentation parameters. A total of 88 rabbits were distributed to four groups with 22 animals each and fed diets containing 0, 50, 100 and 150 g/kg of MSC, respectively. The in vitro assays were conducted employing cecum inoculum on the same dietary treatments. The inclusion of MSC yielded a quadratic effect on in vitro dry matter digestibility (p < 0.001). The maximum amount of produced gas was raised linearly with the inclusion of MSC (p = 0.016). MSC linearly reduced several variables as the nutritional contribution of caecotrophs in dry matter (p = 0.017) and crude protein (p = 0.014), live weight at 51 d (p = 0.024), body weight gain (p = 0.039), average daily feed intake (ADFI) (p = 0.001) and feed conversion ratio (FCR) (p = 0.007) in the first period evaluated (30-50 d); furthermore the ADFI and FCR the second (51-72 d) and whole period (30-72 d) (p < 0.001). MSC addition caused a quadratic effect on white blood cells count (p = 0.026) and a linear decrease of eosinophils (p = 0.045). In conclusion, the inclusion of up to 150 g/kg of MSC improves the in vitro digestibility and fermentation potential of the diets, reflecting on the ADFI and FCR of the animals, although adverse effects are observed on the weight of the commercial carcass and nutritive contribution of the caecotrophs.