The addition of alpha amylase improves the quality of Chinese dried noodles.

The effect of α-amylase on the quality attributes of Chinese dried noodles (CDN) was investigated. Adding α-amylase markedly decreased the cooking time and cooking loss of CDN at the level of 12.5 (mg/100 g flour). The elasticity of CDN was increased significantly (P < 0.05) after adding α-amylase. The firmness of noodles with 12.5 mg α-amylase per 100 g flour showed no obvious change compared to the control, whereas it decreased significantly (P < 0.05) when the amount of α-amylase increased to 25 (mg/100 g flour). In addition, the chewiness of CDN with 12.5 mg α-amylase per 100 g flour increased, while it showed a significant (P < 0.05) decreasing trend with further increased α-amylase levels. Starch structural and thermal properties were also changed by α-amylase, which showed increased relative crystallinity, swelling power, but decreased pasting property. The changed starch property restrained the cross-linking of gluten. The decrease in optimal cooking time and increase in elasticity of CDN were due to the increased swelling power and decreased peak time of the starch. In addition, the decreased setback of starch and protein cross-linking degree were responsible for the decreased firmness and chewiness of CDN with α-amylase ranging from 25 to 50 mg/100 g flour. Overall, α-amylase could be used as a functional additive to improve the quality of CDN when the amount was at 12.5 mg/100 g flour.

Utilization of corn-based diets supplemented with an exogenous α-amylase for broilers.

A study was conducted to evaluate the effects of a supplemental α-amylase on energy and nutrient utilization of broiler chickens fed diets with variable amounts of corn. A total of 480 slow feathering Cobb × Cobb 500 male broilers were randomly distributed into 10 treatments with 8 replicates of 6 birds each. Birds were fed a common starter to 14 D post-hatch. The experimental diets were provided subsequently until 25 D, which were a conventional corn-soy basal diet (CS) and a corn-soy diet displaced with 40% of corn (CN). These were fed as-is or supplemented with 40, 80, 120, or 160 kilo-Novo α-amylase units (KNU)/kg. Dietary treatments were distributed factorially as a 2 × 5 arrangement (diet type vs. amylase). Samples of feed, excreta, and ileal digesta were analyzed for determination of ileal digestible energy (IDE), ME, total tract retention, and digestibility of dry matter, protein, and fat. No interactions between diet type and amylase were observed. The CN diet had lower (P < 0.05) energy utilization and nutrient digestibility when compared to the CS diet. AMEn and IDE increased (P < 0.05) by 110 and 207 kcal/kg, respectively, when CS and CN diets were supplemented with 80 KNU/kg. The amylase added to the CS diet led to quadratic increases (P < 0.05) on growth performance, IDE, AME, and AMEn, as well as in dry matter, protein, and fat digestibility. Energy utilization and crude protein digestibility were linearly increased (P < 0.05) when amylase was added to the CN diet or the extrapolated 100% of corn. In conclusion, energy utilization, digestibility of crude protein, fat, and dry matter increased with amylase supplementation in corn-soy-based diets. When amylase was tested in a complete diet having 53.6% corn, 100 and 105 KNU/kg maximized AMEn and IDE, respectively; however, the maximum energy response in the CN diet or 100% of corn was not achieved until 160 KNU/kg, suggesting an association between amylase dose optimization and dietary starch concentration.

Feeding the combination of essential oils and exogenous α-amylase increases performance and carcass production of finishing beef cattle.

Two experiments were conducted to evaluate the performance responses of finishing feedlot cattle to dietary addition of essential oils and exogenous enzymes. The treatments in each experiment consisted of (DM basis): MON-sodium monensin (26 mg/kg); BEO-a blend of essential oils (90 mg/kg); BEO+MON-a blend of essential oils plus monensin (90 mg/kg + 26 mg/kg, respectively); BEO+AM-a blend of essential oils plus exogenous α-amylase (90 mg/kg + 560 mg/kg, respectively); and BEO+AM+PRO-a blend of essential oils plus exogenous α-amylase and exogenous protease (90 mg/kg + 560 mg/kg + 840 mg/kg, respectively). Exp. 1 consisted of a 93-d finishing period using 300 Nellore bulls in a randomized complete block design. Animals fed BEO had higher DMI (P < 0.001) but similar feed efficiency to animals fed MON (P ≥ 0.98). Compared with MON, the combination of BEO+AM resulted in 810 g greater DMI (P = 0.001), 190 g greater average daily gain (P = 0.04), 18 kg heavier final body weight (P = 0.04), and 12 kg heavier hot carcass weight (P = 0.02), although feed efficiency was not significantly different between BEO+AM and MON (P = 0.89). Combining BEO+MON tended to decrease hot carcass weight compared with BEO alone (P = 0.08) but not compared with MON (P = 0.98). Treatments did not impact observed dietary net energy values (P ≥ 0.74) or the observed:expected net energy ratio (P ≥ 0.11). In Exp. 2, five ruminally cannulated Nellore steers were used to evaluate intake, apparent total tract digestibility of nutrients, and ruminal parameters in a 5 × 5 Latin square design. Feeding BEO increased the total tract digestibility of CP compared to MON (P = 0.03). Compared to MON, feeding the combination of BEO+MON increased the intake of CP (P = 0.04) and NDF (P = 0.05), with no effects on total tract digestibility of nutrients (P ≥ 0.56), except for a tendency (P = 0.09) to increase CP digestibility. Intakes of all nutrients measured, except for ether extract (P = 0.16) were greater in animals fed BEO+AM when compared with MON (P ≤ 0.03), with no differences on total tract nutrient digestibilities (P ≥ 0.11) between these two treatments. In summary, diets containing the BEO used herein enhanced DMI of growing-finishing feedlot cattle compared with a basal diet containing MON without impair feed efficiency. A synergism between BEO and AM was detected, further increasing cattle performance and carcass production compared to MON.

Skeletal muscle and liver gene expression profiles in finishing steers supplemented with Amaize.

Our main objective was to evaluate the effects of feeding α-amylase (Amaize, Alltech Inc., Nicholasville, KY, USA) for 140 days on skeletal muscle and liver gene transcription in beef steers. Steers fed Amaize had lower average daily gain (p = .03) and gain:feed ratio (p = .05). No differences (p > .10) in serum metabolites or carcass traits were detected between the two groups but Amaize steers tended (p < .15) to have increased 12th rib fat depth. Microarray analysis of skeletal muscle revealed 21 differentially expressed genes (DEG), where 14 were up-regulated and seven were down-regulated in Amaize-fed steers. The bioinformatics analysis indicated that metabolic pathways involved in fat formation and deposition, stress response, and muscle function were activated, while myogenesis was inhibited in Amaize-fed steers. The quantitative PCR results for liver revealed a decrease (p < .01) in expression of fatty acid binding protein 1 (FABP1) and 3-hydroxybutyrate dehydrogenase 1 (BDH1) with Amaize. Because these genes are key for intracellular fatty acid transport, oxidation and ketone body production, data suggest a reduction in hepatic lipid catabolism. Future work to investigate potential positive effects of Amaize on cellular stress response, muscle function, and liver function in beef cattle appears warranted.

Impact of α-amylase supplementation on energy balance and performance of high-yielding dairy cows on moderate starch feeding.

In dairy cows, exogenous α-amylase is suggested to improve starch utilization and positively affect performance and health traits linked to energy balance and fertility. In a 1-year feeding experiment, 421 cows were orally supplemented with α-amylase (treatment: 12.5 g/kg dry matter (DM) addition rate to a concentrated feed) or non-supplemented (control) on the basis of an ad libitum total mixed ration (TMR). Every cow was allocated to a high- (≥32 kg milk/day) or late-lactation group (<32 kg milk/day), in which the TMR starch content was 220 ± 20.8 g/kg DM and 183 ± 24.8 g/kg DM, respectively. The energetic effect of α-amylase supplementation seemed to be exclusively related to the high-lactation stage (5-100 days in milk) in primiparous cows, where the daily milk yield was 32 ± 0.49 versus 31 ± 0.50 kg per cow in the treatment versus control group (P < 0.05). The pluriparous cows did not benefit from the supplementation that way. In neither primiparous nor pluriparous cows, was the milk composition, the fat-to-protein ratio, the somatic cell score, the backfat thickness, serum total bilirubin, ß-hydroxybutyrate and the fertility found to be systematically affected by α-amylase supplementation.

THESIS-ABSTRACT Supplementation levels of exogenous alpha-amylase in broilers diets.

This study aimed to evaluate the supplementation levels of an exogenous alpha-amylase in broilers diets and compare two indicators in determining the diets energy. The experiment was divided into two parallel evaluations, being one of performance and the other of metabolism. In performance assay, 1,700 one-day-old Cobb-500 male chicks were used. The animals were distributed in 50 experimental plots and evaluated five treatments with ten replicates in a completely randomized design (CRD). The treatments were: a positive control (PC), a negative control (NC) and three alpha-amylase supplementation levels 200, 400 and 600 g/t, and the NC was formulated with 50 and 90 kcal of energy reduction in relation to the PC to the phases from 1 to 21 days and from 22 to 42 days, respectively. In the metabolism assay were used 240 animals, 150 birds for stage from 14 to 21 days and 90 birds to stage from 35 to 42 days of age and the treatments were the same as the performance assay, with six replicates per treatment in CRD. All diets of metabolism test contained the digestibility indicators Lipe® (eucalyptus purified lignin) and chromic oxide (Cr2O3), in concentrations of 0.05 and 1.0%, respectively. In the period from 1 to 21 days old, no significant differences were observed in weight gain (WG) (P > 0.05), however, feed intake (FI) was found higher by using 200 ppm of enzyme (P < 0.05) and better feed conversion (FC) with the PC (P < 0.05). From 22 to 42 days, no significant differences were observed on the WG (P > 0.05), but were observed lower FI and better FC to PC treatment (P < 0.05). In the period from 1 to 42 days of age, significant differences were also not observed on the WG (P > 0.05), but there was lower FI and better FC for the PC treatment (P < 0.05). The AMEn (apparent metabolizable energy corrected for nitrogen balance), determined using the total collection, reaffirmed the values ​​calculated for the PC and NC with intermediate data obtained from the enzyme use (200, 400 and 600 ppm). Comparing the total collection using Lipe® and Cr2O3, a correlation was observed only for the PC results, that were always higher, and for the NC results, that were lower for the three methodologies. For IDE (ileal digestible energy), determined by Cr2O3, significant differences were observed (P < 0.05) and it presented higher values in the PC treatment and lower values in the NC. In IDE determining by Lipe®, significant was observed (P < 0.05), showing higher value in the PC treatment. It is concluded that in the metabolism assessments, exogenous alpha-amylase tested was effective in increasing the metabolizable energy (ME), however, not enough to be equivalent to the ME of PC treatment, a result that was better expressed in the total collection, AMEn by Lipe® and IDE by Lipe® methodologies. The performance results reflect the superiority of PC treatment, pointing enzyme limitation to supply the energy deficit practiced in this work.

Experiments suggesting extra-digestive effects of enteral pancreatic amylase and its peptides on glucose homeostasis in a pig model.

The studies presented were designed to highlight the impact of pancreatic enzymes on glycemic control and insulin response. Blood glucose and plasma insulin levels were monitored after intravenous, oral or direct gut glucose tolerance tests (GTT) in 6 pigs with an intact gastrointestinal tract and in 12 pigs following duodenal-jejunal bypass (DJB) surgery. In the intact pigs, pancreatic enzymes (Creon®) given orally 1 h prior to the GTT, lowered the blood glucose levels during the oral and meal GTT and reduced the plasma insulin response during the intravenous and meal GTT. In DJB pigs, blood glucose and plasma insulin levels were higher following glucose loading into the by-passed biliopancreatic limb as compared to that following glucose loading orally or into the common intestinal limb. Infusion of amylase or amylase peptides together with glucose into the biliopancreatic limb lowered blood glucose levels in DJB pigs. These preliminary data suggest new, extra-digestive, actions of enteral pancreatic enzymes - probably amylase or its peptides - on glucose homeostasis, with an reduction in net glucose absorption into the blood and in insulin response. This ability of digestive enzymes (amylase) to reduce post-prandial hyperglycaemia in an insulin-independent manner could aid in preventing the development of obesity and diabetes.

Effect of different amylases on the utilization of cornstarch in broiler chickens.

This study compared the effect of different amylases on the utilization of cornstarch in broiler chickens fed a corn-based diet. Three-day-old Arbor Acres plus male chickens were randomly divided into 7 treatments and fed a diet supplemented with different sources and concentrations of amylase: 1,500 U/kg and 3,000 U/kg α-1,4 amylase from Aspergillus oryzae (α-amylase A); 480 U/kg and 960 U/kg α-1,4 amylase from Bacillus subtilis (α-amylase B); 200 U/kg and 400 U/kg α-1,6 isoamylase from B. subtilis; and the control. The experimental period comprised 11 d, during which performance, nutrient digestibility, digestive enzyme activity, intestinal morphology, and glucose transporter transcription of the chickens were evaluated. The results indicated that 1,500 U/kg α-amylase improved the digestibility of energy and decreased the feed conversion rate compared to α-1,6 isoamylase (P < 0.05). Supplemental 400 U/kg α-1,6 isoamylase decreased ileal digestibility of amylopectin and total starch (P < 0.05) compared to 200 U/kg α-1,6 isoamylase, α-amylase A, α-amylase B, and the control (P < 0.05). Supplemental α-1,6 isoamylase decreased (P < 0.05) insulin content. Supplemental 3,000 U/kg α-amylase A and α-1,6 isoamylase increased (P < 0.05) the relative weight of the liver. In addition, 3,000 U/kg α-amylase A, 480 U/kg α-amylase B, and α-1,6 isoamylase decreased the V:C in the duodenum and ileum. α-amylase A increased sucrase activity in the jejunum (P < 0.05), whereas 400 U/kg α-1,6 isoamylase reduced maltase activity in the duodenum (P < 0.05). Furthermore, 3,000 U/kg α-amylase A and α-amylase B decreased (P < 0.05) sodium/glucose cotransporter 1 (SGLT1) mRNA expression in the duodenum and jejunum. However, 200 U/kg α-1,6 isoamylase increased glucose transporter 2 (GLUCT2) in the duodenum (P < 0.05). These results suggest that exogenous amylase affects the digestibility of starch by affecting disaccharidase activity in the intestine, nutrient requirements for intestinal maintenance by the V:C, and nutrient absorption and metabolism via GLU transporter mRNA expression. Different sources and concentrations of amylases had varying effects on broilers.

Starch digestibility, energy utilization, and growth performance of broilers fed corn-soybean basal diets supplemented with enzymes.

A study was conducted to evaluate the effects of dietary α-amylase and ß-xylanase supplementation of corn-soy diets, formulated with or without supplemental phytase, on growth performance, energy utilization, and starch digestibility in broiler chickens. A total of 336 slow-feathering, Cobb × Cobb 500 male broilers were randomly distributed to 6 treatments having 8 replicates of 7 birds each. Birds were fed a common starter diet to d 14 post-hatch (3,050 kcal/kg AMEn, 21.7% CP, 1.05% Ca, and 0.53% nPP). The experimental diets were provided afterwards until d 25. A 2 × 3 factorial arrangement of 2 control diets (basal = corn-soy diet without added phytase or PHY = corn-soy diet formulated with 1,000 phytase units/kg) and 3 carbohydrase supplementations (0, 80 kilo-Novo α-amylase units/kg, or 80 kilo-Novo α-amylase units/kg + 100 fungal ß-xylanase units/kg) was used from d 14 to 25. Excreta were collected from 21 to 24 d and all birds were euthanized at 25 d for jejunum and ileum content collection. Samples of feed, excreta, and jejunal and ileal digesta were analyzed for determination of total tract retention and ileal apparent digestibility. No interactions between diet and carbohydrase were observed. Broilers fed diets formulated with phytase or supplemented with amylase + xylanase had higher BW gain (BWG) and lower FCR (P < 0.05) when compared with birds fed diets without carbohydrases. Relative to the basal diet, AMEn was increased (P < 0.01) by 70 kcal/kg and 99 kcal/kg when birds were fed the diet supplemented with amylase and amylase + xylanase, respectively. Starch digestibility in the jejunum and ileum was increased (P < 0.05) by 3.5% and 2.4%, respectively, when birds were fed the diet supplemented with amylase + xylanase. Results from this experiment show that corn-soy diets having phytase and supplemented with amylase and xylanase led to increased growth performance, AMEn, and starch digestibility in broilers. Furthermore, the efficacy of exogenous amylase and xylanase was independent of the presence of microbial phytase.

Improvement of starch digestion using α-amylase entrapped in pectin-polyvinyl alcohol blend.

Polyvinyl alcohol (PVA) and pectin blends were used to entrap α-amylase (Termamyl) using glutaraldehyde as a cross-linker. The effect of glutaraldehyde concentration (0.25, 0.5, 0.75, 1.0, and 1.25%) on the activity of the immobilized enzyme and rate of enzyme released was tested during a 24 h period. Characteristics of the material, such as scanning electron microscopy (SEM), tensile strength (TS), elongation, and rate of dissolution in water (pH 5.7), ruminal buffering solution (pH 7.0), and reactor containing 0.1 mol L(-1) sodium phosphate buffer (pH 6.5), were also analyzed. SEM results showed that the surfaces of the pectin/PVA/amylase films were highly irregular and rough. TS values increased as a function of glutaraldehyde concentration, whereas percentage of elongation (%E) decreased. Pectin/PVA/amylase films presented similar values of solubility in the tested solvents. The material obtained with 0.25% glutaraldehyde performed best with repeated use (active for 24 h), in a phosphate buffer reactor. By contrast, the material obtained with 1.25% glutaraldehyde presented higher performance during in vitro testing using an artificial rumen. The results suggest that pectin/PVA/amylase is a highly promising material for biotechnological applications.

Development of enteric submicron particles formulation of α-amylase for oral delivery.

Enteric submicron particles (SPs) formulations of α-amylase were prepared by w/o/w emulsion solvent evaporation using hydroxypropyl methylcellulose phthalate (HPMCP) and Eudragit L 100, to avoid gastric inactivation of α-amylase. Smaller internal and external aqueous phase volume provided maximum encapsulation efficiency (71.92-73.40%), least particle size (546.4-595.4 nm) and 23-26% loss of enzyme activity. Release studies in 0.1 N HCl confirmed the gastro-resistance of formulations. The anionic SPs aggregated in 0.1 N HCl (i.e. gastric pH 1.2), due to protonation of carboxylic groups of enteric polymer. The aggregates being < 500 µm size would not impede gastric emptying. However, at pH >5.0 (duodenal pH), SPs showed de-aggregation due to restoration of surface charge. HPMCP and Eudragit L 100 SPs facilitated almost complete release of α-amylase within 30 min at pH 6.0 and 6.8, respectively, following Higuchi kinetics. PXRD and DSC indicated amorphous character and scanning electron microscope showed spherical shape of SPs. In simulated gastro-intestinal pH condition, HPMCP and Eudragit L 100 SPs showed good digestion of cooked rice and could serve as potential carrier for oral enzyme delivery. Stability studies indicated the formulations as quite stable to ensure 2 years shelf life at room temperature.

Selection of commercial hydrolytic enzymes with potential antifouling activity in marine environments.

In this work, the marine antifouling potential of some commercially available hydrolytic enzymes acting on the main constituents of extracellular polymeric substances (EPS) involved in bacterial biofilm formation was determined. The selected protease (i.e., alpha-chymotrypsin from bovine pancreas), carbohydrase (i.e., alpha-amylase from porcine pancreas) and lipase (from porcine pancreas) exhibited remarkable hydrolytic activities towards target macromolecules typically composing EPS under a wide range of pHs (6.5-9.0 for alpha-chymotrysin and alpha-amylase; 7.0-8.5 for the lipase) and temperatures (from 10 °C to 30 °C), as well as relevant half-lives (from about 2 weeks to about 2 months), in a marine synthetic water. The activity displayed by each enzyme was poorly affected by the co-presence of the other enzymes, thus indicating their suitability to be employed in combination. None of the enzymes was able to inhibit the formation of biofilm by an actual site marine microbial community when applied singly. However, a mixture of the same enzymes reduced biofilm formation by about 90% without affecting planktonic growth of the same microbial community. This indicates that multiple hydrolytic activities are required to efficiently prevent biofilm formation by complex microbial communities, and that the mixture of enzymes selected in this study has the potential to be employed as an environmental friendly antifouling agent in marine antifouling coatings.

Effect of extrusion cooking and amylase addition to gruels to increase energy density and nutrient intakes by Vietnamese infants.

Extrusion cooking and amylase addition are two processing methods used for the preparation of high energy dense (ED) gruels of suitable consistency. A quantitative study of energy and nutrient intakes of 67 infants aged 6 to 10 months in rural areas in Vietnam was carried out to compare the effects of these processes used alone or in combination. Twice a day, for a period of four days each, infants successively ate four gruels prepared from different flours based on a blend of rice, sesame and soybean: an instant flour obtained by extrusion cooking (gruel A), a ready-to-cook flour obtained by extrusion cooking plus alpha-amylase addition (gruel B), a flour produced by milling crude rice, sesame and roasted soybean plus alpha-amylase addition (gruel C) and without amylase (control gruel D). Gruels A, B and C had a high ED of respectively 94, 122 and 124 kcal/100 g while the control gruel D had a low ED (59 kcal/100 g). The intakes of the four gruels were inversely linked to their ED. However, despite the fact that gruels B and C had similar ED, larger intakes were obtained with gruel B, which was attributed to better acceptability. The average energy intakes of high ED gruels A, B and C, respectively 112, 134 and 117 kcal/meal, were significantly higher than that of gruel D (81 kcal/meal). Of the three processing methods, the one combining extrusion cooking and amylase addition gave the best results in terms of gruel acceptability and energy intake.

Modulation of key metabolic enzyme of Labeo rohita (Hamilton) juvenile: effect of dietary starch type, protein level and exogenous alpha-amylase in the diet.

A 60-day feeding trial was conducted to delineate the effect of both gelatinized (G) and non-gelatinized (NG) corn with or without supplementation of exogenous alpha-amylase, either at optimum (35%) or sub-optimum (27%) protein levels, on blood glucose, and the key metabolic enzymes of glycolysis (hexokinase, HK), gluconeogenesis (glucose-6 phosphatase, G6Pase and fructose-1,6 bisphosphatase, FBPase), lipogenesis (glucose-6 phosphate dehydrogenase, G6PD) and amino acid metabolism (alanine amino transferase, ALT and aspartate amino transferase, AST) in Labeo rohita. Three hundred and sixty juveniles (average weight 10 +/- 0.15 g) were randomly distributed into 12 treatment groups with each of two replicates. Twelve semi-purified diets containing either 35 or 27% crude protein were prepared by including G or NG corn as carbohydrate source with different levels of microbial alpha-amylase (0, 50, 100 and 150 mg kg(-1)). The G corn fed groups showed significantly higher (P < 0.05) blood glucose and G6PD activity, whereas G6Pase, FBPase, ALT and AST activity in liver was higher in the NG corn fed group. Dietary corn type, alpha-amylase level in diet or their interaction had no significant effect (P > 0.05) on liver HK activity, but the optimum crude protein (35%) fed group showed higher HK activity than their low protein counterparts. The sub-optimum crude protein (27%) fed group showed significantly higher (P < 0.05) G6PD activity than the optimum protein fed group, whereas the reverse trend was observed for HK, G6Pase, FBPase, ALT and AST activity. Addition of 50 mg alpha-amylase kg(-1) feed showed increased blood glucose and G6PD activity of the NG corn fed group, whereas the reverse trend was found for G6Pase, FBPase, ALT and AST activity in liver, which was similar to that of the G or NG corn supplemented with 100/150 mg alpha-amylase kg(-1) feed. Data on enzyme activities suggest that NG corn in the diet significantly induced more gluconeogenic and amino acid metabolic enzyme activity, whereas G corn induced increased lipogenic enzyme activity. Increased amino acid catabolic enzyme (ALT and AST) activity was observed either at optimum protein (35%) irrespective of corn type or NG corn without supplementation of alpha-amylase irrespective of protein level in the diet.

An evaluation of exogenous enzymes with amylolytic activity for dairy cows.

An experimental (7B) and a commercial (AMA) formulation of enzymes, both primarily with alpha-amylase activity, were evaluated for activity at various pH values, stability in ruminal fluid, the potential to improve in vitro ruminal fermentations, and the potential to improve production performance of lactating cows. When incubated (40 degrees C) in buffer with a pH between 5.4 and 6.0, 7B had about 10 to 25 times greater amylase activity than AMA, and enzyme activity in this range increased by 100% for 7B, whereas activity decreased by about 26% for AMA. Both formulations maintained enzyme activity when they were incubated in in vitro ruminal fermentations for 24 h. After 6 h of ruminal in vitro fermentation, additions of 7B resulted in linear increases in apparent total volatile fatty acid production for flint and dent corn but had no effect on floury corn. In a lactation trial, 28 Holstein cows (68 +/- 31 d in milk, 46.9 +/- 9.1 kg of milk/d) were fed a total mixed ration (TMR) supplemented with nothing (CON), a low dose of 7B [7BL, 0.88 mL/kg of TMR dry matter (DM)], a high dose of 7B (7BH, 4.4 mL/kg of TMR DM), or AMA (0.4 g/kg of TMR DM). The experiment was conducted as a 4. 4 Latin square design with 21-d periods. Cows fed 7BL, 7BH, and AMA ate similar amounts of DM, and cows fed the latter 2 diets consumed more DM than did cows fed CON. Cows fed 7BL produced more milk than cows fed CON and 7BH, but produced similar amounts to cows fed AMA. The production of 3.5% fat-corrected milk was greater from cows fed 7BL and AMA compared with cows fed CON. The percentages of milk fat and milk protein were unaffected by treatment. Total-tract digestion of DM and organic matter were greater for cows fed 7BL compared with those fed CON. The addition of exogenous amylase enzymes to the diets of lactating dairy cows has the potential to improve animal productivity.

Fortified complementary foods with or without alpha-amylase treatment increase hemoglobin but do not reduce breast milk intake of 9-mo-old Zambian infants.

BACKGROUND: Malnutrition in late infancy in developing countries may result from poor-quality complementary foods that displace breast milk. OBJECTIVE: The objective of the study was to assess the effects of fortified complementary blends of different energy densities on growth, hemoglobin concentrations, and breast milk intake of 9-mo-old Zambian infants. DESIGN: Infants were randomly assigned at 6 mo of age to receive for 3 mo a fortified blend of maize, beans, bambaranuts, and groundnuts [Chilenje Baby Mix (CBM); energy density: 68 kcal/100 g; n = 37] or a similar blend with alpha-amylase (CBMA; energy density: 106 kcal/100 g; n = 44). Cross-sectional data were obtained at 9 mo for a control group of infants (n = 69) not given the diets. Breast milk intake was measured by using the dose-to-the-mother deuterium dilution technique. RESULTS: No differences in weight or length z scores, all of which were within normal ranges, were seen between groups at 9 mo. Percentage fat mass was significantly (P = 0.01) greater in the infants in both the CBM (23.2 +/- 2.7%) and CBMA (23.4 +/- 2.5%) groups than in the control group (21.6 +/- 2.6%). Hemoglobin concentrations were significantly (P = 0.03) greater in both intervention groups (CBM group: 104 +/- 12 g/L: CBMA group: 103 +/- 12 g/L) than in the control group (98 +/- 14 g/L). Breast milk intake was not significantly (P = 0.87) different between groups (CBM group: 614 +/- 271 g/d; CBMA group: 635 +/- 193 g/d; control group: 653 +/- 221 g/d). CONCLUSIONS: The study foods improved hemoglobin concentrations without reducing breast milk intake and may be used to improve the nutritional status of infants in developing countries.

Effects of lactic acid fermentation and gamma irradiation of barley on antinutrient contents and nutrient digestibility in mink (Mustela vison) with and without dietary enzyme supplement.

The experiment was conducted to study the effects of fermentation of barley, using two different strains of lactic acid bacteria, a Lactobacillus plantarum/pentosus strain isolated from spontaneously fermented rye sourdough (AD2) and a starch-degrading Lactobacillus plantarum (AM4), on contents of mixed-linked (1 --> 3) (1 --> 4)-beta-glucans, alpha-amylase inhibitor activity, inositol phosphates, and apparent digestibility of macronutrients in mink. Effects of fermentation were compared with effects of gamma irradiation (gamma-irradiation: 60Co gamma-rays at 25 kGy). The diets were fed to mink with and without a supplementary enzyme preparation. Both lactic acid fermentation and gamma-irradiation followed by soaking and incubation, reduced concentrations of soluble beta-glucans, phytate and alpha-amylase inhibitor activity. Dietary enzyme supplementation increased significantly digestibility of crude protein, fat, starch and crude carbohydrate (CHO). Fermentation of the barley increased digestibility of starch and CHO. Fermentation with lactic acid bacteria AD2 resulted in higher starch and CHO digestibility than strain AM4, and had greater effect than gamma-irradiation, soaking and incubation. The highest digestibility of starch and CHO was obtained after AD2 fermentation followed by enzyme supplementation. It is concluded that both lactic acid fermentation of barley and enzyme supplementation have positive nutritional implications in the mink by limiting the effects of antinutrients and improving digestibility and energy utilization.

Production of rice protein by alkaline extraction improves its digestibility.

Rice seed endosperm has two types of protein bodies (PB). Type I protein body (PB-I) accumulates prolamin and is hard to digest, while type II protein body (PB-II) mainly consists of glutelin, an easily digestible protein. A simple method to process rice protein and improve its digestibility was tested from the viewpoint of its application to food manufacturing. Rice protein prepared by alkaline extraction followed by neutralization sedimentation (AE-RP) was compared with that prepared by starch degradation by alpha-amylase (SD-RP). The crude protein content of AE-RP and SD-RP was 84.7% and 78.2%, respectively. There were no major differences in protein composition among AE-RP, SD-RP and rice flour by SDS-PAGE, except 16 kDa polypeptide. With respect to amino acids, all the groups showed quite similar compositions, although cysteine and methionine were lower in AE-RP. In an in vitro digestion study with pepsin and pancreatin, both the SDS-PAGE analysis of protein pattern and the crude protein content of undigested residue clearly demonstrated that AE-RP has a higher digestibility than SD-RP. To find the cause of the difference in digestibility, the structural property of protein bodies by two production methods was compared using electron microscopy. PB-II of AE-RP was transformed into small, amorphous granules, while that of SD-RP was still kept partial protein body structures. PB-I of AE-RP kept its protein body structure, but produced double layers. From the finding that glutelin-gold was detected by immunochemistry not only in small, amorphous granules but also in PB-I, mainly the cortex layer, in AE-RP, it became clear that PB-I was swollen and fragile as a result of alkali treatment. These results strongly indicate that the improvement in digestibility of AE-RP is a result of the structural change of PB-I and -II caused by alkaline extraction.

Effects of dietary alpha-amylase on metabolism and performance of transition dairy cows.

Twenty-four multiparous Holstein cows [body weight, 759 kg (SD = 30 kg); body condition score, 3.2 (SD = 0.13)] were used in a randomized complete block design to determine the effect of feeding alpha-amylase during the transition period on rumen fermentation, key metabolic indicators, and lactation performance. Cows were assigned to either a control diet or the control diet supplemented with alpha-amylase (662 fungal amylase units per gram, AMA) at 0.1% of diet dry matter (DM). Experimental diets were fed from 21 d before expected calving through 21 d in milk. From 22 to 70 d in milk, all cows were fed a similar lactation cow diet. Average pre- and postpartum DM intakes were 12.4 and 17.8 kg/d, respectively, and did not differ between treatments; however, DM intakes during the last week prepartum decreased to a greater degree in AMA than control cows compared with wk -2. Supplementing diets with alpha-amylase tended to increase proportions of ruminal butyrate prepartum but not postpartum. Treatment differences were not detected for concentrations of insulin in plasma and lipid and glycogen in liver tissue. Prepartum, concentrations of beta-hydroxybutyrate and nonesterified fatty acids were increased in cows fed AMA compared with the control diet. Postpartum, concentrations of glucose in plasma tended to be increased by feeding AMA. Increased plasma beta-hydroxybutyrate and nonesterified fatty acids pre- but not postpartum and a tendency for increased plasma glucose postpartum demonstrate shifting reliance from lipid- to carbohydrate-based metabolism postpartum in cows fed alpha-amylase.

The influence of treatment with dual purpose bacterial inoculants or soluble carbohydrates on the fermentation and aerobic stability of bermudagrass.

This study determined the effectiveness of an inoculant (BB), molasses, or a mixture of either BB and molasses (BBM) or BB and fibrolytic enzymes (BBE) for improving the fermentation and aerobic stability of bermudagrass. A 6-wk regrowth of Tifton 85 bermudagrass was conserved in quadruplicate mini silos alone or after treatment application. The inoculant contained a mixture of P. pentosaceus 12455, 1 x10(5) cfu/g of fresh forage, L. buchneri 40788, 4 x10(5) cfu/g of fresh forage, and beta-glucanase, alpha-amylase, and xylanase; BBE contained similar bacteria and enzymes as BB, but greater enzyme activities. Chemical composition was quantified after 2, 4, 7, 30, and 60 d of ensiling. Microbial composition and aerobic stability were measured after 60 d of ensiling, at which point the pH of additive-treated silages was consistently lower and DM recovery was higher than in untreated silages. The BB, BBM, and molasses-treated silages had less ammonia N than untreated silages, and BB, BBM, and BBE-treated silages had less residual water-soluble carbohydrates than untreated silages. All silages had high acetic acid (47.5 g/kg DM) and low lactic acid (1.7 g/kg DM) concentrations. However, untreated and BBE-treated silages had more butyric acid and ammonia N, suggesting that a clostridial fermentation had occurred. These butyric forages were more aerobically stable (27 d) but less desirable for feeding than those ensiled with BB or molasses, which were stable for 6.9 d. In conclusion, BB and molasses treatments improved the digestibility and fermentation of bermudagrass and produced higher quality silages that were stable for 6.9 d. Mixing BB with molasses or the inoculant tested was not more beneficial than BB or molasses alone.