T. A. Woyengo

Anticancer effects of phytosterols

Phytosterol and stanol (or phytosterols) consumption reduces intestinal cholesterol absorption, leading to decreased blood LDL-cholesterol levels and lowered cardiovascular disease risk. However, other biological roles for plant sterols and stanols have also been proposed. The objective of this review is to critically examine results from recent research regarding the potential effects and mechanisms of action of phytosterols on forms of cancer. Considerable emerging evidence supports the inhibitory actions of phytosterols on lung, stomach, as well as ovarian and breast cancer. Phytosterols seem to act through multiple mechanisms of action, including inhibition of carcinogen production, cancer-cell growth, angiogenesis, invasion and metastasis, and through the promotion of apoptosis of cancerous cells. Phytosterol consumption may also increase the activity of antioxidant enzymes and thereby reduce oxidative stress. In addition to altering cell-membrane structure and function, phytosterols probably promote apoptosis by lowering blood cholesterol levels. Moreover, consumption of phytosterols by healthy humans at the recommended level of 2 g per day does not cause any major health risks. In summary, mounting evidence supports a role for phytosterols in protecting against cancer development. Hence, phytosterols could be incorporated in diet not only to lower the cardiovascular disease risk, but also to potentially prevent cancer development.

Energy and amino acid utilization in expeller-extracted canola meal fed to growing pigs.

Two experiments were conducted to determine the nutritive value of expeller-extracted canola meal (EECM) for growing pigs. In Exp. 1, a total of 6 ileally cannulated barrows (average initial BW = 26.8 kg) were fed 3 diets in a replicated 3 x 3 Latin square design to determine the apparent and standardized ileal digestibility (SID) values of N and AA and the SID AA contents of EECM. The 3 diets were a cornstarch-based diet with either solvent-extracted canola meal (SECM) or EECM as the sole source of protein, and a low-casein cornstarch-based diet, which was used to estimate basal endogenous N and AA losses to determine the SID of N and AA. All 3 diets contained chromic oxide as an indigestible marker for determining nutrient digestibility by the indicator method. In Exp. 2, a total of 18 intact barrows (average initial BW = 25.9 kg) were fed 3 diets in a completely randomized design (6 pigs per diet) to determine apparent total tract digestibility and retention of nutrients and the DE and ME contents of EECM. The diets were a basal corn-based diet or the basal diet with corn replaced by 35% SECM or EECM. The basal diet was used for determining the total tract digestible nutrient content by the difference method. Solvent-extracted canola meal, which is commonly used in the formulation of swine diets, was fed in both experiments for comparison with EECM. The SECM and EECM were similar in CP content (41.8 vs. 41.4%). Expeller-extracted canola meal was, however, greater in ether extract content (12.03 vs. 5.54%) and decreased in NDF content (23.8 vs. 29.9%) compared with SECM. The EECM also had a greater content of all the AA except Met, Cys, and Ser, by approximately 6.6%; Cys was greater in SECM, whereas Met and Ser were similar between the 2 meals. The EECM had greater (P < 0.05) SID of N, Arg, Ile, Leu, Phe, Glu, and Pro. The SID contents of Arg, His, Ile, Leu, Phe, Val, Ala, Asp, Glu, Gly, Pro, and Tyr were also greater (P < 0.05) for EECM than for SECM by an average of 15%. The EECM had greater (P < 0.01) DE (4,107 vs. 3,790 kcal/kg) and ME (3,978 vs. 3,564 kcal/kg) values compared with SECM. The results show that the EECM used in the current study had greater digestible AA and energy and a greater ME content than the SECM; hence, it may be a better source of protein and energy for growing pigs than SECM.

Nonruminant Nutrition Symposium: Controlling feed cost by including alternative ingredients into pig diets: a review.

Sustained price increases for traditional cereal grain and protein meal feed commodities have forced the pork industry to consider the dietary inclusion of alternative feedstuffs. Crop seed may serve as feedstuffs but their demand as feedstock for human food, biofuel, and bioindustrial products has increased. Together with these products, coproducts such as distillers dried grains with solubles, wheat millrun, and canola meal are produced. As omnivores, pigs are ideally suited to convert these non-human-edible coproducts into high-quality food animal protein. Therefore, coproducts and other low-cost alternative feedstuffs such as pulses and oilseeds can be included in pig diets to reduce feed cost per metric ton of feed. However, inclusion of alternative feedstuffs in pig diets does not necessarily reduce feed cost per kilogram of gain. Therefore, the use of novel and existing feedstuffs in pig diets must be optimized following their characterization for energy and AA profile. Alternative feedstuffs generally have a high content of at least 1 of the following antinutritional factors (ANF): fiber, tannins, glucosinolates, and heat-labile trypsin inhibitors. Several methods can optimize nutrient use of pigs fed alternative feedstuffs by reducing effects of their ANF. These methods include 1) particle size reduction to increase nutrient digestibility, 2) dehulling or scarification to reduce tannin and fiber content of pulses and oilseeds, 3) air classification to create fractions that have a greater content of nutrients and lower content of ANF than the feedstock, 4) heat treatments such as extrusion, toasting, roasting, and micronization to reduce heat-labile ANF, 5) dietary supplementation with fiber-degrading enzymes or predigestion of fibrous feedstuffs or diets with fiber-degrading enzymes to increase dietary nutrient availability, and 6) formulation of diets based on bioavailable AA coefficients. In conclusion, the feeding of alternative ingredients may reduce feed cost per unit of pork produced provided that their price per unit NE or digestible lysine is less than that of the traditional feedstuffs and that negative effects of their ANF are controlled.

Nutrient digestibility and performance responses of growing pigs fed phytase- and xylanase-supplemented wheat-based diets

Three experiments were conducted to evaluate the effect of supplementing phytase and xylanase on nutrient digestibility and performance of growing pigs fed wheat-based diets. In Exp. 1, 10 diets were fed to 60 pigs from 20 to 60 kg of BW to determine the effect of combining phytase and xylanase on apparent total tract digestibility (ATTD) of nutrients and growth performance. The 10 diets included a positive control diet (PC; 0.23% available P; 0.60% Ca) and a negative control diet (NC; 0.16% available P; 0.50% Ca) supplemented with phytase at 0, 250, and 500 fytase units (FTU)/kg and xylanase at 0, 2,000, and 4,000 xylanase units (XU)/kg in a 3 x 3 factorial arrangement. In Exp. 2, 6 ileally cannulated barrows (initial BW = 35.1 kg) were fed 4 wheat-based diets in a 4 x 4 Latin square design, with 2 added columns to determine the effect of combining phytase and xylanase on apparent ileal digestibility (AID) of nutrients. The 4 diets were NC (same as that used in Exp. 1) or NC supplemented with phytase at 500 FTU/kg, xylanase at 4,000 XU/kg, or phytase at 500 FTU/kg plus xylanase at 4,000 XU/kg. In Exp. 3, 36 barrows (initial BW = 55.5 kg) were fed 4 diets based on prepelleted (at 80 degrees C) and crumpled wheat for 2 wk to determine the effect of phytase supplementation on ATTD of nutrients. The 4 diets fed were a PC (0.22% available P; 0.54% Ca) and a NC (0.13% available P; 0.43% Ca) alone or with phytase at 500 or 1,000 FTU/kg. All diets in the 3 experiments contained Cr(2)O(3) as an indigestible marker. No synergistic interactions were detected between phytase and xylanase on any of the response criteria measured in Exp. 1 or 2. There were no dietary effects on growth performance in Exp. 1. In Exp. 1, phytase at 250 FTU/kg increased the ATTD of P and Ca by 51 and 11% at 20 kg of BW or by 54 and 10% at 60 kg of BW, respectively, but increasing the level of phytase to 500 FTU/kg only increased (P < 0.05) ATTD of P at 20 kg of BW. In Exp. 2, phytase at 500 FTU/kg increased (P < 0.05) the AID of P and Ca by 21 and 12%, respectively. In Exp. 3, phytase at 500 FTU/kg improved (P < 0.05) ATTD of P by 36%, but had no further effect at 1,000 FTU/kg. Xylanase at 4,000 XU/kg improved (P < 0.05) AID of Lys, Leu, Phe, Thr, Gly, and Ser in Exp. 2. In conclusion, phytase and xylanase improved P and AA digestibilities, respectively, but no interaction between the 2 enzymes was noted.

Growth performance and nutrient utilization of broiler chickens fed diets supplemented with phytase alone or in combination with citric acid and multicarbohydrase

An experiment was conducted to determine the effect of supplementing a corn-soybean meal-based diet with phytase alone or in combination with citric acid (CA) or multicarbohydrase, a preparation containing nonstarch polysaccharide-degrading enzymes, or both, on growth performance, nutrient utilization, and bone mineralization. A total of 360 one-day-old broiler chicks were assigned to 6 dietary treatments, consisting of 12 pens of 5 birds each, and were fed experimental diets from 1 to 21 d of age. The diets included a positive control (0.46% nonphytate P; 1.1% Ca) and a negative control (NC; 0.26% nonphytate P; 0.89% Ca) without or with phytase (600 U/kg) alone, phytase plus CA (5 g/kg), phytase plus multicarbohydrase (Superzyme OM; 0.6 g/kg), or phytase (Ronozyme P-CT) plus CA and multicarbohydrase. Birds fed the positive control diet had higher (P<0.05) BW gain (764 vs. 594 g/21 d) and tibia ash content (50.0 vs. 38.3%) than those fed the NC diet. Phytase improved (P<0.05) BW gain (632 g/21 d), which increased further (P<0.05) to 673 g/21 d for the phytase plus multicarbohydrase diet. In contrast to phytase alone, phytase plus multicarbohydrase supplementation improved (P<0.05) feed conversion ratio of the NC diet from 1.37 to 1.32. Tibia ash content for the NC diet increased (P<0.05) from 38.3 to 42.4% due to phytase addition. Phytase improved (P<0.05) ileal digestibility of P from 29.5 to 43%, and the addition of CA or multicarbohydrase, or both, to a phytase-supplemented diet further increased (P<0.05) P digestibility to 51.5, 53.4, and 54.3%, respectively. Phytase addition improved (P<0.05) diet AMEn content from 2,959 to 3,068 kcal/kg, which tended (P<0.06) to increase further with CA (3,150 kcal/kg) or multicarbohydrase (3,142 kcal/kg) addition. No beneficial interactions were detected between CA and multicarbohydrase for all response criteria measured. Results show that addition of multicarbohydrase to the phytase-supplemented broiler diets improved nutrient utilization and growth performance.

Metabolizable energy and standardized ileal digestible amino acid contents of expeller-extracted canola meal fed to broiler chicks

An experiment was conducted to determine the standardized ileal digestible amino acid (AA) and AMEn contents of expeller-extracted canola meal (EECM) fed to broiler chicks. One hundred forty-four broiler chicks were divided into 24 groups of 6 birds balanced for BW and fed 4 diets in a completely randomized design (6 groups per diet) from d 14 to 21 of age. The diets were a corn-soybean meal-based basal diet formulated to meet NRC nutrient requirements, the basal diet with energy- and AA-yielding ingredients replaced by 30% of either solvent-extracted canola meal (SECM) or EECM, and a low-protein casein-cornstarch-based diet. The SECM, which is commonly used in formulating poultry diets, was fed for comparison with EECM, whereas the casein-cornstarch-based diet was fed to estimate basal endogenous AA losses for determining standardized ileal digestibility of AA. All 4 diets contained titanium oxide (0.3%) as an indigestible marker, and nutrient digestibility and retention were determined by the substitution method. From d 19 to 21, excreta samples were collected for AMEn determination. On d 21, the birds were killed by cervical dislocation, and contents of the whole ileum were obtained for determination of AA digestibility. Expeller-extracted canola meal had greater (P<0.05) standardized ileal digestible contents of Gly, Leu, Ser, Thr, Asp, and Glu and tended to have greater (P<0.10) standardized ileal digestible contents of Ile, Lys, Phe, Ala, and Tyr than SECM. Compared with SECM, EECM had greater (P<0.001) AMEn (2,694 vs. 1,801 kcal/kg). The results show that the EECM evaluated in the current study had greater standardized ileal digestible AA and AMEn contents than SECM, and hence, it may be a better source of protein and energy for broiler chicks than SECM. The standardized ileal digestible AA and AMEn values of EECM used in the current study could be used when formulating broiler chicken diets using the same to minimize the N excretion and feeding cost.

Ileal digestibility and endogenous flow of minerals and amino acids: responses to dietary phytic acid in piglets

Effects of phytic acid (PA) on ileal mineral and amino acid (AA) digestibilities and ileal endogenous AA flow in piglets were investigated. Seven ileal-cannulated weanling pigs were fed a casein-maize starch-based diet with PA (as sodium phytate) at 0, 5, 10 or 20 g/kg in 4 x 4 Latin square design with three added columns to give seven observations per treatment. The basal diet was formulated to meet National Research Council energy and AA requirements for piglets. The respective digestibility and endogenous lysine loss were determined by indicator and homoarginine methods. The apparent ileal digestibility (AID) of Na, K and P was linearly and quadratically reduced (P < 0.05) by increased dietary PA concentration, whereas that of Ca and Mg was only linearly reduced (P < 0.05) by the dietary PA. The AID values for Mg and Na were negative ( - 0.03 and - 0.18, respectively) when PA was supplemented at 20 g/kg. The AID of isoleucine, leucine and valine responded quadratically to dietary PA concentration, though the differences between the AID values of the AA due to change in dietary PA concentration were marginal (at most by 1.8 percentage units). Furthermore, dietary PA did not affect (P>0.05) endogenous AA losses. The results suggest that PA has limited effect on the digestibility and endogenous losses of AA in piglets, but can reduce AID of Mg and Na partly by increasing endogenous losses of these minerals as evidenced by their negative AID values.

Growth performance, organ weights, and blood parameters of broilers fed diets containing expeller-extracted canola meal.

A study was conducted to determine the effect of including expeller-extracted canola meal (EECM) in diets for broilers on performance, thyroid gland size, liver and kidney sizes, blood serum concentration of triiodothyronine and tetraiodothyronine, hemoglobin content in blood, hematocrit, and histology of liver and kidney. A total of 200 male broiler chicks (1 d old) were divided into 40 groups of 5 birds balanced for BW and fed 5 diets in a completely randomized design (8 groups/diet) from d 1 to 21 of age. The diets were a complete corn-soybean meal-based basal diet with 0, 10, 20, 30, or 40% of EECM. Diets were formulated to have the same ME, CP, Ca, nonphytate P, and standardized ileal digestible Met and Lys contents. The EECM contained (% of DM) 37.8% CP, 0.74% Met, 2.14% Lys, 1.62% Thr, 1.61% Val, and 7.64 μmol/g of glucosinolates. An increase in dietary level of EECM from 0 to 40% resulted in a linear decrease in feed intake (P < 0.001) by 4.8 g/21-d period for each 1% increase in EECM and in BW gain (P < 0.001) by 6.0 g/21-d period for each 1% increase in EECM. However, dietary EECM linearly increased liver weight relative to live BW (P < 0.001) and serum tetraiodothyronine concentration (P = 0.019). An increase in dietary level of EECM from 0 to 40% did not result in a significant increase in kidney weight relative to live BW. There was no effect of EECM on heart and thyroid gland weights relative to live BW or on the blood hemoglobin content, hematocrit, and serum triiodothyronine concentration. In conclusion, an increase in dietary level of EECM resulted in reduced growth performance and may interfere with liver function, likely because of increased dietary concentration of glucosinolates. Thus, the amount of EECM included in broiler diets should be based on the desired growth performance and the cost of the EECM.

Enzymes enhance degradation of the fiber-starch-protein matrix of distillers dried grains with solubles as revealed by a porcine in vitro fermentation model and microscopy.

Effects of treating corn and wheat distillers dried grains with solubles (DDGS) with a multicarbohydrase alone or in combination with a protease on porcine in vitro fermentation characteristics and the matrix structure of the DGGS before and after the fermentation were studied. Three DDGS samples (wheat DDGS sample 1 [wDDGS1], wheat DDGS sample 2 [wDDGS2], and corn DDGS [cDDGS]) were predigested with pepsin and pancreatin. Residues were then subjected to in vitro fermentation using buffered mineral solution inoculated with fresh pig feces without or with a multicarbohydrase alone or in combination with protease in a 3 × 3 factorial arrangement. Accumulated gas production was measured for up to 72 h. Concentration of VFA was measured in fermented solutions. The matrix of native DDGS and their residues after fermentation was analyzed using confocal laser scanning microscopy and scanning electron microscopy to determine internal and external structures, respectively. On a DM basis, wDDGS1, wDDGS2, and cDDGS contained 35.5, 43.4, and 29.0% CP; 2.23, 0.51, and 6.40% starch; 0.82, 0.80, and 0.89% available Lys; and 24.8, 22.5, and 23.0% total nonstarch polysaccharides, respectively. The in vitro digestibility of DM for wDDGS1, wDDGS2, and cDDGS was 67.7, 72.1, and 59.6%, respectively. The cDDGS had greater ( < 0.05) total gas and VFA production than both wheat DDGS. The wDDGS2 had lower ( < 0.05) total gas production than wDDGS1. Multicarbohydrase increased ( < 0.05) total gas production for cDDGS and total VFA production for wDGGS1 but did not increase gas or VFA production for wDDGS2. Addition of protease with multicarbohydrase to DDGS reduced ( < 0.05) total gas and VFA productions and increased ( < 0.05) branched-chain VFA regardless of DDGS type. Confocal laser scanning microscopy and scanning electron microscopy revealed that DDGS were mainly aggregates of resistant and nonfermentable starchy and nonstarchy complexes formed during DDGS production. After in vitro fermentation with porcine fecal inoculum, particles of enzyme-treated DDGS were generally smaller than those of the untreated DDGS. In conclusion, cDDGS had a more porous matrix that was more fermentable than the wheat DDGS. The wDDGS2 was less fermentable than wDDGS1. Multicarbohydrase increased fermentability of cDDGS and wDDGS1 but not wDDGS2, indicating that its efficacy in DDGS is dependent on matrix porosity and DDGS source. Protease hindered efficacy of multicarbohydrase.

Effect of a carbohydrase mixture on ileal amino acid digestibility in extruded full-fat soybeans fed to finishing pigs 1 2

Extrusion technology has been used successfully to improve the nutritive value of full-fat oilseeds via shear force and heat applied during passage through the extruder, exposing more peptide bonds to enzymatic hydrolysis. However, the fibrous portion of the seeds is largely intact after extrusion. Therefore, application of carbohydrase mixtures targeting nonstarch polysaccharides might further improve the nutritive value of extruded full-fat oilseeds. This hypothesis was investigated in a study involving 6 ileal-cannulated barrows (average initial BW = 75.0 kg) fed extruded full-fat, soybean- (FFSB) based diets, without or with a carbohydrase mixture (CM) to determine apparent ileal digestibility (AID) of energy and standardized ileal digestibility (SID) of AA. The CM supplement provided 500, 50, 400, 1200, 450, and 45 units of pectinase, cellulase, mannanase, xylanase, glucanase, and galactanase, respectively, per kilogram of diet. A basal diet was formulated to contain FFSB as the sole source of AA, whereas the CM diet was formulated by supplementing the basal diet with CM. Diets contained titanium dioxide as an indigestible marker. Diets were fed in a 2-period crossover design to give 6 observations per diet. Each experimental period lasted 7 d, including a 5-d adaptation period and 2-d ileal digesta collection period. The SID of N and AA were calculated using published values for ileal endogenous N and AA losses from our laboratory. Enzyme supplementation increased (P < 0.01) AID values of DM (68.7 vs. 65.7%), GE (74.6 vs. 70.5%), and N (64.2 vs. 58.5%). Greater (P < 0.05) AID values were recorded for Leu, Met + Cys, Thr, Cys, Ser, and Tyr in the CM diet compared with the basal diet. Compared with the basal diet, the CM diet had greater SID values for N (73.7 vs. 68.6%; P < 0.01), Met + Cys (59.9 vs. 52.2%; P < 0.05), and Thr (66.3 vs. 61.2%; P < 0.05). The average SID for indispensable and total AA increased by 3.4% and 3.8% units, respectively, after enzyme supplementation. In conclusion, enzyme supplementation increased the nutritive value of extruded FFSB for finishing pigs.