The use of enzyme technology for improved energy utilization from full-fat oilseeds. Part I: canola seed.

The effect of carbohydrase enzyme supplementation on energy utilization from full-fat canola seed was investigated in a TMEn assay with adult roosters and in a nutrient digestibility and growth performance study with broiler chickens. In the TMEn assay, enzyme preparations C (cellulase, 340 U/g), XG (xylanase, 63,600 U/g and glucanase, 48,300 U/g), P (pectinase, 10,000 U/g), and MC (mannanase, 10,900 U/g and cellulase, 600 U/ g), alone and in combination (C + P, C + XG, C + MC, P + XG, P + MC, XG + MC, C + P + XG, C + P + MC, and C + P + XG + MC), were evaluated at an inclusion level of 0.1%. On average, hammer-milled canola seed with a TMEn content of 3,642 kcal/kg showed an increase (P < 0.05) to 4,783 kcal/kg following supplementation with the enzyme blends C + P + XG, C + P + MC, and C + P + XG + MC. A similar pattern of increase (P < 0.05) in fat (80.4 vs. 63.5%) and nonstarch polysaccharide (NSP; 20.4 vs. 4.4%) digestibilities was observed. Enzyme combination C + P + XG was further evaluated in a 2-wk (5- to 18-d) trial with broiler chickens fed isonitrogenous and isoenergetic corn and soybean meal-based diets containing canola seed (15%), the corresponding canola meal (8.85%) plus canola oil (6.15%) mixture, or canola seed (15%) supplemented with 3 different levels (0.002, 0.01, or 0.05%) of the enzyme. Poorer (P < 0.05) feed:gain (1.412 vs. 1.344), lower (P < 0.05) total tract DM (65.9 vs. 70.7%) and fat (69.6 vs. 88.0%) digestibilities, lower AMEn content (2,963 vs. 3,200 kcal/kg), and lower ileal fat (65.6 vs. 85.6%) and protein (75.6 vs. 81.2%) digestibilities were observed for the canola seed diet compared with the canola meal plus canola oil diet. Enzyme supplementation of the canola seed diet resulted in an improvement (P < 0.05) in feed:gain; total tract DM, fat, and NSP digestibilities; AMEn content; and ileal fat digestibility. Although the enzyme effect on ileal and total tract fat digestibilities was significant at both high and medium inclusion levels, other parameters showed the significant improvement only when the highest inclusion rate of enzyme was used. These data support the need for carbohydrase enzyme supplements in poultry diets containing full-fat canola seed.

The use of enzyme technology for improved energy utilization from full-fat oilseeds. Part II: flaxseed.

An in vitro incubation study was carried out to determine whether various carbohydrase preparations contained appropriate activities to target nonstarch polysaccharides (NSP) of full-fat flaxseed. Enzyme preparations C (cellulase, 340 U/g), XG (xylanase, 63,600 U/g and glucanase, 48,300 U/g), P (pectinase, 10,000 U/g), and MC (mannanase, 10,900 U/g and cellulase, 600 U/ g), alone and in combination (C + P, C + XG, P + XG, C + P + XG, C + P + MC, and C + P + XG + MC), were evaluated. Triplicate samples of defatted flaxseed meal (0.1 g) were incubated with 1% single enzymes or combinations at 45 degrees C and pH 5.2. A more pronounced degradation of NSP was achieved when the enzyme preparations were used in concert. Compared with the control (no enzyme) treatment, the degree of NSP degradation averaged 34.7% when the sample was incubated with the 3 most effective enzyme combinations (C + P + XG, C + P + MC, and C + P + XG + MC). The effect of carbohydrase enzyme supplementation on energy utilization from full-fat flaxseed was investigated in a TMEn assay with adult roosters. When compared with the nonsupplemented sample, an increase (P < 0.05) in TMEn content from 2,717 to 3,751 kcal/kg (on average) was observed for the flaxseed supplemented with enzymes C + P + XG, C + P + MC, and C + P + XG + MC. A similar pattern of increase (P < 0.05) in fat and NSP digestibilities was noted. Enzyme combination C + P + XG was further evaluated in a 2-wk (5- to 18-d) trial with broiler chickens fed a corn and soybean meal-based flaxseed (15%) diet or the flaxseed diet supplemented with the enzyme at 3 different levels: 0.002, 0.01, and 0.05%. When supplemented at the highest level, the enzyme blend improved (P < 0.05) feed:gain, total tract DM, fat and NSP digestibilities, AMEn content, and ileal fat digestibility. No effect of enzyme supplementation, regardless of the level used, on ileal protein digestibility and digesta viscosity was observed. The results of the current study suggest that multiactivity carbohydrase enzyme supplements may be used as a means to improve energy utilization from full-fat flaxseed and, thus, enhance its feeding value for poultry.

Amino acid digestibility in dry extruded-expelled soybean meal fed to pigs and poultry.

The digestibility of AA in dry extruded-expelled soybean meal (DESBM) and regular, solvent-extracted soybean meal (SBM) were determined in pigs and poultry. In the pig assay, 4 Cotswold barrows (average initial BW of 80.4 kg) fitted with a T-cannula at the distal ileum were allotted to 4 semipurified diets in a 4 x 4 Latin square design. Diet 1, a low protein diet (5% casein), was used to quantify endogenous CP and AA losses. Diets 2, 3, and 4 were formulated to contain 35% regular, solvent-extracted SBM; batch 1 of DESBM (DESBM-1); and batch 2 of DESBM (DESBM-2), respectively, as the sole source of protein. The DESBM samples were obtained from 2 different batches but were subjected to the same processing conditions. Chromic oxide (0.3%) was included as a digestibility marker in all diets. Compared with DESBM-1 and DESBM-2, apparent ileal digestibility of DM in SBM was greater (P < 0.05). Apparent and true ileal digestibilities of AA in SBM were greater (P < 0.05) compared with DESBM-2. In the poultry assay, 4 dietary treatments were each assigned to adult cecectomized roosters in a completely randomized design. Treatment 1 was a nonnitrogenous diet (NND; 90% sucrose and 10% vegetable oil) used to estimate endogenous N and AA losses. Treatments 2, 3, and 4 contained SBM, DESBM-1, and DESBM-2 as the only source of protein. Each of these diets was fed in 25-g quantities formulated to provide 5 g of CP from the respective soybean meal source. The SBM had greater (P < or = 0.05) true digestibility for isoleucine, leucine, cysteine, proline, serine, and tyrosine compared with DESBM-1. The results indicate that, relative to regular, solvent-extracted soybean meal, AA digestibilities of different batches of dry extruded-expelled soybean meal varied in pigs and poultry.

Prevalence of class 1 integrons and antimicrobial resistance gene cassettes among enteric bacteria found in multisite group-level cohorts of humans and swine.

The prevalence of antimicrobial resistance genotypic characteristics (class 1 integrons and antimicrobial resistance gene cassettes) among commensal Escherichia coli isolated from humans and swine in a semiclosed, integrated farrow-to-fork population was evaluated in a cross-sectional study. The objective of this study was to establish baseline antimicrobial resistance patterns of enteric bacteria from animals and humans within the study population; specifically, genotypic traits both unique and common to commensal E. coli derived from the different sources were evaluated. There were significant differences between host species; swine isolates were more likely to harbor integrons (odds ratio = 2.33, P = 0.0487). No significant differences were found for facility location, facility type, human housing cohort, or time of day (P > 0.05). There were significant differences (P = 0.006) among swine production groups (fecal samples from boars, dry sows, finishers, growers, intake boars, lactating sows, the lagoon, nursery piglets, influent, and piglets); the grower group was less likely than the nursery group to harbor a class 1 integron (nursery as referent: odds ratio = 0.22, P = 0.04). Among all isolates with an integron present, human isolates were more likely to harbor an antimicrobial resistance gene cassette (odds ratio = 6.36, P = 0.003). When isolates that possessed gene cassettes coding for resistance to specific antimicrobials were compared, no significant differences between host species (P > 0.05) were observed.

Vancomycin-resistant Enterococcus faecium strains isolated from community wastewater from a semiclosed agri-food system in Texas.

Vancomycin-resistant Enterococcus faecium strains (VRE) were isolated from human wastewater but not swine fecal waste from a semiclosed agri-food system in Texas. Forty-nine VRE isolates possessed vanA, and one possessed vanB. Twenty-one pulsed-field gel electrophoresis types were identified and segregated into three groups. There was evidence of clonal dissemination among geographically separated sites.

Patterns of antimicrobial resistance among commensal Escherichia coli isolated from integrated multi-site housing and worker cohorts of humans and swine.

We examined antimicrobial resistance (AR) phenotypes among commensal Escherichia coli isolated from fecal matter of humans and swine housed in a semi-closed and uniquely integrated multi-site farrow-to-plate operation. Aggregate cohorts of humans consisted of (1) "control" groups of consumers, (2) groups of swine workers, and (3) groups of slaughter-plant workers. Analyses of cross-sectional AR data from 472 human and 376 swine isolates are presented. AR phenotypes among these isolates were compared by (1) host species, (2) facility location, (3) facility type, (4) housing (human) or production (swine) cohort, and (5) sample collection period and time of day. There were significant (p < 0.05) differences in isolates among host-species with swine uniformly at greater risk for (1) AR to four specific antimicrobials (kanamycin, streptomycin, sulfamethoxazole, tetracycline), and (2) multiple resistance phenotypes (p < 0.0001). Facility type and unit location were more often associated with AR differences among swine isolates than among human isolates. Swine production group was significantly associated with AR prevalence (p < 0.05) for nine antimicrobials; in general, purchased boars, suckling piglets, weaned piglets, and lactating sows were at higher risk of AR. There was no significant (p > 0.05) association of human occupational/consumer cohort with AR prevalence. Several unique AR phenotypes were detected in each of the human- and swine-intake groups. These data establish baseline characteristics for an on-going 3-year longitudinal study designed to further characterize AR phenotype and genotype in this population. Host-, facility-, and cohort-specific data demonstrate that sufficient prevalence differences exist to permit the future quantification of AR transmission, should it occur. Based on these cross-sectional data, occupational exposure to either swine-rearing or swine-slaughter facilities does not appear to be associated with the prevalence of phenotypic resistance among the commensal fecal E. coli isolated from this integrated system.

Degradation of cell wall polysaccharides by combinations of carbohydrase enzymes and their effect on nutrient utilization and broiler chicken performance.

In vitro incubation studies were carried out to determine if various carbohydrase preparations contained appropriate activities to target nonstarch polysaccharides (NSP) of wheat, soybean meal (SBM), canola meal, and peas. Triplicate samples (0.1 g) were incubated with a number of carbohydrase preparations (i.e., cellulase, pectinase, xylanase, glucanase, galactanase, and mannanase) or their combinations at 45 degrees C and pH 5.2. A more pronounced degradation of NSP was achieved when the enzyme preparations were used in concert. When compared with the control (nonenzyme treatment), the highest degree of NSP degradation reached was 37% for wheat, and 36, 26, and 28% for canola meal, SBM, and peas, respectively. Four enzyme combinations were studied further in a 2-wk (5 to 18 d of age) growth performance and nutrient digestibility trial with broiler chickens. All enzyme combinations were effective in improving (P < 0.05) weight gain, feed-to-gain ratio, AMEn, apparent ileal digestibilities of starch and protein, and apparent total tract digestibility of NSP in birds fed a wheat, wheat screening, SBM, canola meal, and peas-based diet. The most complex enzyme combination was found to be superior (P < 0.05) to others in improving ileal protein digestibility and feed-to-gain ratio. The effectiveness of this combination in elimination of the nutrient-encapsulating effect of cell walls was further evaluated in a balance study with adult roosters fed a conventionally ground full-fat canola seed. Enzyme addition increased (P < 0.05) NSP digestibility from 11.1 to 30.1%, which, in turn, resulted in a marked increase (P < 0.05) in TMEn value (4.176 vs 4.744 Mcal/kg) of the seed. It is evident from the present studies that the addition of an appropriate combination of carbohydrase enzymes to target cell wall polysaccharide structures could further improve enzyme efficacy in practical wheat, SBM, canola meal, and peas-based broiler diets.

Exogenous interleukin-12 (IL-12) exacerbates Cryptosporidium parvum infection in gamma interferon knockout mice.

Experimental infection of BALB/c- or C57BL/6-gamma-interferon-knockout (GKO) mice with Cryptosporidium parvum results in infection in both strains with different outcomes of disease. The BALB/c-GKO mice recover from infection, whereas the C57BL/6-GKO mice succumb to infection in less than 2 weeks. Differences in cytokine mRNA expression suggested that recovery may involve other cytokines. To determine whether the addition of either a Th1 or Th2 cytokine could alter the outcome of infection, we treated GKO mice with either recombinant (r)IL-4 or rIL-12 1 day before infection (DBI) or daily. No effect on the oocyst shedding patterns in either strain nor an increase in survival of the C57BL/6-GKO mice was observed in the rIL-4-treated mice. Whereas one dose of 0.5 microg rIL-12 given 1 DBI had no effect on oocyst shedding, we found that daily doses of rIL-12 administered intraperitoneally exacerbated C. parvum infection in both animal models. Administration of rIL-12 shortened the survival time in the C57BL/6-GKO mice and prevented BALB/c-GKO mice from recovering from infection. Specific proliferation of T cells to cryptosporidial antigen and Th1 and Th2 mRNA cytokine expression was markedly decreased in rIL-12-treated mice. Nitric oxide (NO) may have played a minor role in the decreased proliferation observed since levels of NO present in the splenocyte cultures from rIL-12-treated mice in response to parasite antigen stimulation were higher than those observed in controls. Thus, we propose that resistance to and recovery from C. parvum infections involves a fine balance in the amount and timing of Th1 and Th2 cytokines.

Melatonin receptor RNA expression in Xenopus retina.

Melatonin is an indolamine hormone presumably synthesized by retinal photoreceptors, and may act as a paracrine signal of darkness within the retina. Previous studies have suggested that melatonin, acting through specific receptors, may be involved in cyclic retinal functions such as photoreceptor outer segment disc shedding and phagocytosis, and modulation of neurotransmitter release in the inner retina. The goal of this study was to determine if melatonin receptor mRNA is expressed in the neural retina and retinal pigment epithelium (RPE) of Xenopus laevis. Sheets of RPE, devoid of contaminating cells, were obtained from Xenopus eyes, and epithelial cultures were subsequently established on microporous membrane filters in a defined medium. Total RNA was isolated from whole brain, neural retina, fresh RPE sheets, and cultured RPE cells. RNA expression of the three known Xenopus melatonin receptor subtypes (MEL1A, 1B, and 1C) was determined by reverse-transcription/polymerase chain reaction (RT/PCR) amplification, followed by Southern hybridization with RNA probes. PCR-amplified cDNA encoding melatonin receptor subtypes 1B and 1C, but not 1A, were detected in reverse-transcribed RNA obtained from brain, neural retina and RPE. RPE cells grown in culture for two weeks also demonstrated 1B and 1C receptor RNA expression. This study suggests that RNA encoding the 1B and 1C melatonin receptor subtypes is expressed in the neural retina and RPE of Xenopus retina, and the expression persists in RPE cells when grown in culture. The expression of melatonin receptor RNA in the RPE may reflect a regulatory role for melatonin in some diurnal events that occur in this tissue, such as phagocytosis of photoreceptor outer segment membranes, and intracellular migration of pigment granules.

Oligosaccharides in canola meal and their effect on nonstarch polysaccharide digestibility and true metabolizable energy in poultry.

Balance studies utilizing laying hens and adult cockerels were conducted to determine the influence of oligosaccharides (raffinose and stachyose) present in canola meal (CM) on the digestibility of nonstarch polysaccharides (NSP) and on the TMEn of the meal. Ethanol extraction was used to produce oligosaccharide-free meal, and exogenous dietary enzymes (alpha-galactosidase and invertase) were employed to bring about oligosaccharide hydrolysis in the intestinal tract of the birds. In each of two balance trials, six hens individually housed were randomly allotted to each of the experimental diets in completely randomized design. Experiment 1 consisted of a factorial arrangement of treatments (two sources of proteins with or without enzyme supplementation), whereas Experiment 2 consisted of five diets: semipurified CM control, semipurified ethanol-extracted CM; semipurified ethanol-extracted CM plus raffinose; conventional CM; and conventional ethanol-extracted CM. Elimination of oligosaccharides by the use of exogenous dietary enzymes had no effect on NSP digestion. Removal of oligosaccharides by ethanol extraction increased NSP digestibility from 4 to 8%. A more pronounced effect (17% NSP digestion) was noted in hens fed a wheat-based diet containing 30% oligosaccharide-free CM. This latter effect may have been due to the relatively high content of water-soluble polysaccharides contributed by the wheat portion of the diet. The TMEn content of ethanol-extracted CM was 2,302 kcal/kg as compared with 2,426 kcal/kg for untreated CM. The data indicate no advantage of oligosaccharide removal with regard to the nutritive worth of canola meal.

Estimation of nitrogen-corrected true metabolizable energy of two different barley samples with and without enzyme supplementation over different excreta collection times.

The TMEn values of two barley samples and a corn sample with and without enzyme addition were determined in an experiment conducted over two consecutive weekly periods. Adult roosters were not influenced by the high beta-glucan content of Scout barley, which had a higher energy value (3.70 kcal/g DM) than the Bedford barley (3.44 kcal/g DM). Overall the energy value of the grain increased 3% due to enzyme supplementation. The 48-h excreta collection time was considered to be adequate for TMEn determination.

A rapid high-performance liquid chromatographic method for the quantitation or uric acid in excreta and tissue samples.

A high-performance liquid chromatographic assay for uric acid in excreta and tissue samples has been developed. The method uses a reversed-phase system with a C18-bonded column, it is sensitive, reliable, and rapid, and it yields quantitative recovery of uric acid.

Effect of the addition of varied salt levels on the performance of growing chickens fed rye diets.

A series of feeding trials were conducted with Single Comb White Leghorn cockerels and broiler chickens to determine if salt per se was a contributing factor in the growth-depressing properties of rye. When added salt level increased from .3 to .6% in rye-based diets growth rate and feed conversion efficiency in young chickens improved significantly (P less than or equal to .05) but not to that of corn-fed birds. The relative growth rate of chickens fed rye diets containing .3% added salt was 78 to 86% of that of birds fed rye diets with .6% added salt.

Utilisation of rye by chickens: effect of microbial status, diet gamma irradiation and sodium taurocholate supplementation.

Several experiments were conducted to determine the influence of intestinal microflora when rye diets are fed to young chicks. In a conventional environment dietary rye severely depressed growth, amino acid and fat retention, and metatarsal bone ash. These conditions could be effectively alleviated by gamma irradiation of the diet and maintenance in a germ-free environment. In gnotobiotic chicks associated with streptococci dietary rye caused effects similar to those seen in a conventional environment, however the responses were less severe. Since addition of sodium taurocholate improved fat retention from a rye diet to a greater extent than from a wheat diet, a deficiency of conjugated bile salts might contribute to the steatorrhea observed in rye-fed chicks.

Improvement of the nutritive value of rye for broiler chickens by gamma irradiation-induced viscosity reduction.

A study was undertaken with chickens to determine the effect of irradiation treatment on the viscosity-inducing properties of polysaccharide components of rye. Three-week body weight, food utilisation, fat retention, and bone ash of chicks were substantially improved by irradiating rye (0 to 10 Mrad) and were maximal at 6 Mrad. Irradiation of the entire diet resulted in no further improvement over irradiating the rye fraction alone. The improved performance coincided with radiation-induced damage to rye polysaccharides, as indicated by reduced viscosity and increased concentrations of reducing sugars.

Influence of rye and dietary salt level on water and sodium metabolism in intact and colostomized roosters.

A study of water and Na metabolism was conducted with 24 roosters fed diets based on either corn or rye with two levels (.4 and 1.0%) of added salt. A diet containing water-extracted rye and a diet based on corn with a freeze-dried water extract of rye added at a level of 12% were also used in the study. Measurements were made on intact and colostomized roosters. In intact roosters dry matter metabolizability was depressed when rye diets were compared with corn diets. Measurements in feces from colostromized roosters fed rye as compared to those fed corn indicated that moisture, viscosity, and water holding capacity were increased and that bulk density was decreased. Diet salt level did not influence the responses regarding these parameters, but water extraction of rye completely alleviated the effects of rye on dry matter metabolizability and viscosity and partially reduced the influence of rye on fecal moisture while not altering the responses regarding water holding capacity or bulk density of feces. With the exception of feces moisture, the water extract of rye had no influence regarding these parameters. Roosters fed rye in comparison to those fed corn showed increases in water intake and excreta moisture content and decreases in urine sodium concentrations and plasma clearance of sodium. The response to rye regarding these latter parameters was dependent on diet salt level. The data indicated a reduced availability of sodium at the cellular level in rye-fed birds, which was manifest in a difference in route of excretion of sodium such that urine was the major route in corn-fed birds and feces was the major route for birds fed rye. The dietary fiber content of rye appeared to be a major factor in rye influencing sodium availability.

Tolerance of young turkey poults to various combinations of dietary furazolidone and salt.

Three feeding trials were conducted to study the tolerance of young turkey poults to furazolidone and to various combinations of salt and furazolidone in the diet. Poults of mixed sexes tolerated up to 0.03% dietary furazolidone from hatch to six weeks of age without harmful effects as judged from the data on mortality rate, feed intake, body weight and plasma composition. High mortality with cardiac dilation and ascites occurred in poults fed the same basal diet containing 0.05 or 0.07% furazolidone. Mortality was positively related to levels of dietary furazolidone, and occurred mainly between two and four weeks of age. The cumulative feed intake and body weight of these poults were significantly lower than those of the control poults at six weeks of age. There was indication of decreased renal function in poults on high furazolidone intake and the mechanism of furazolidone-induced cardiac dilation is discussed. Mortality rate, incidence of cardiac dilation with ascites and heart, liver and body weights and feed efficiency were similar in poults fed diets containing 0.022% furazolidone and varying levels of salts (0.5, 1.0 or 1.5%) compared with the control fed the same basal diet containing 0.5% salt from hatch to eight weeks of age. It is concluded that a starter diet containing 0.022% furazolidone and up to 1.5% salt does not affect the performance of poults from hatch to eight weeks of age.