Studies were conducted to investigate the interactive effects of exogenous enzymes andorganic acids on in vitro and in vivo nutrient digestion and growth performance of broiler chicks.In Study 1, five exogenous enzyme products including ??-glucanase, xylanase, amylase, ??-galactosidase and protease, were assayed in triplicate at their optimum pH levels and at pH levelsof 3.0, 6.0, 6.5, 7.0 and 7.5, which were used to simulate pH levels found in the gizzard, the diet,the crop, and the proximal and distal parts of small intestine, respectively. The pH gradient wasobtained by dissolving the enzymes in different buffers. Results suggested that the pH levelscommonly found in the avian digestive tract were either too high or too low for maximumactivity of the exogenous enzymes, such as ??-galactosidase and protease.In Study 2, broiler chicks were fed corn basal, barley basal or wheat basal diets withdifferent levels or different sources of organic acids. Dietary inclusion of graded levels oforganic acids linearly reduced the pH of the diet and crop content, but not the pH of the digestasampled in the gizzard and small intestine. The inclusion of 2% organic acids (citric acid orfumaric acid) in broiler diets had either no effect or negative effects on chick growthperformance.In Study 3, an in vitro model was used to simulate the chicken's digestive process in thecrop, the gizzard and the small intestine. Soybean meal and raw whole soybeanwere used as substrates. Graded levels of either ??-galactosidase (0 to 13,792 units/kg) or protease(0 to 888 units/kg) and 0 or 2% citric acid were added to the substrates in a factorialarrangement. Reducing sugars, ??-amino nitrogen and trypsin inhibitor content were measured.The data indicated that increasing levels of ??-galactosidase linearly increased the release of thereducing sugars from the soybean meal. Addition of citric acid further increased the activity of ??-galactosidase, resulting in more reducing sugars were released. Increasing the supplementarylevels of protease linearly increased the ??-amino nitrogen release from the soybean meal and rawwhole soybean. Trypsin inhibitor content in the raw whole soybean was not influenced by theapplication of the protease.In Study 4, broilers were fed low energy or normal energy basal diets with ??-galactosidase,amylase and acidification of diet and water. Growth performance, AMEn and digestibility ofDM, CP and NDF were observed. Alpha-galactosidase improved the AMEn of the diets andincreased the weight gain and feed intake of broiler chicks. Citric acid decreased the crop pH andenhanced the activity of ??-galactosidase in the crop. Citric acid decreased the AMEn of the dietsand chick growth performance. These effects were corrected by supplementing ??-galactosidase.The activity of ??-galactosidase was enhanced by simultaneously using organic acid. Thenegative effects on chick growth performance by dietary inclusion of organic acids werecorrected by simultaneously using ??-galactosidase.

This experiment was conducted to determine if changing the amount of ideal aminoacids (meaning the amount of amino acids necessary to supply all the animal's needswithout excesses or deficiencies of any single amino acid), in relation to caloric intakewill change nitrogen metabolism and weight loss in obese mature dogs. Informationprovided by this experiment can be used to formulate canine diets emphasizing weightloss in older animals.Six moderately obese mature female crossbred hounds were fed diets varying in theirratio of lysine:calories (Lysine % : Mcal ME/g) (2.2, 3.0, and 3.8) in a 3 x 3 replicatedLatin square design. Increasing the lysine:calorie of the diets linearly increased theamount of nitrogen absorbed. It did not, however, significantly affect blood chemistryvalues. Protein turnover exhibited a positive linear trend with increasing ratio and proteindegradation showed a strong quadratic change with the lowest point of degradationoccurring with the diet containing a 3.0 lysine:calorie ratio. Plasma urea and creatinineexcretion demonstrated quadratic tendencies with the two highest values occurring withthe diets containing lysine:calorie of 2.2 and 3.8, reflecting changes in muscle proteinbreakdown while nitrogen was retained in the body. Caloric restriction did not result inloss of lean mass as much as a loss of fat mass. By increasing the quality of protein fedas a percentage of caloric intake, lean muscle mass was conserved during periods ofcaloric restriction.

The initial study herein assessed mineral digestibility in situations when reducedamounts of inorganic and organic (proteinates) trace minerals (TM) were fed in finishingpigs, and their long-term effects on body mineral status. The second study was aslaughter-investigation that tested the impact of lean growth potential on phosphorusbody accretion from 30 to 110 kg.Organic TM exhibited neither improvement in digestibility nor in total retention;fecal excretion responded quantitatively to mineral intake independently of the source.Contents of copper in kidney and zinc in liver were higher for pigs fed the organic form.Phosphorus content was linearly related to live weight, empty body weight, andnitrogen content. Phosphorus accretion was very similar for both genetic backgrounds,with gilts retaining more mineral (Pandlt;0.05) than barrows. A N/P deposition ratio of 5.14was determined for pigs of both genders and genetic backgrounds to further predictphosphorus requirements based on protein accretion.Reduction of TM waste from growing-finishing pigs may be best addressed bylimiting their dietary inclusion rather than by using organic forms. Data from the secondstudy may be useful for an accurate estimation of phosphorus requirements, whichaccounts for variations in lean accretion rate.

Two experiments were conducted to determine the effect of feeding diets with a 2009 and 2010 naturally-contaminated corn to weaning pigs. For both experiments three diets were blended to contain 100% 2010 naturally-contaminated corn (control), 50-50% blend of the 2009 naturally-contaminated corn and 2010 corn (Diet 2), and 100% 2009 naturally-contaminated corn (Diet 3). In Exp. 1, 24 crossbred pigs with an average body weight of 7.64 ± 0.70 kg were allotted to 4 replicates of 3 treatments with 2 pigs per pen, on the basis of gender, litter mate, and BW in a randomized complete block design. Fecal and urine samples were collected and dry matter, energy, and nitrogen apparent digestibility were determined. Dry matter, energy, and nitrogen digestibility were not affected by either Diet 3 or Diet 2 compared to the control diet. In Exp. 2, 30 crossbred pigs with an average body weight of 7.98 ± 1.15 kg were allotted to 3 replicates of 2 comparisons with 5 pigs per pen. Comparisons consisted of: 1) Control vs Diet 3, and 2) Control vs Diet 2. Two feeders were located in each pen containing one of the two diets. Feed preference and growth performance were determined. A preference for the feed containing 2010 corn feed was observed; pigs showed the ability to discriminate mycotoxin-contaminated feed (95.34 vs. 4.66%; P< 0.01). Nutrient digestibility was not affected by these diets, but a clear decrease in feed intake was observed in the pigs.

Determining digestibility of feed ingredients is a challenge. While forage type feeds may be fed as the sole dietary component, concentrates cannot. To determine the apparent digestibility of these ingredients a by difference method can be utilized. The study was conducted to investigate the nutritional value of corn germ dehydrated (AAFCO 48.32) for horses in comparison to two processed corns commonly fed to horses. The second objective was to compare total tract digestibility of the treatments to determine differences in digestibility of the various fiber fractions due to added concentrate and to use the difference method to determine nutrient digestibility of the three corn treatments. In addition, glycemic responses and fecal pH changes were used to assess and quantify the presence of associative effects in fiber digestibility and differences in site of digestion. A 4x4 Latin square digestibility trial was conducted using a starch intake level of 6 g/kg BW/day, offered in three equal meals. The control diet consisted of hay cubes, alfalfa pellets, corn bran and corn oil. The treatment diets contained the control diet plus one of the three processed corn treatments, cracked, steam flaked or corn germ dehydrated. Cracked corn was selected as a negative control and steam flaked corn as a positive control based on previous research showing differences in pre-cecal starch digestibility coefficients. The four diets were formulated to have equal starch, NDF and ADF components. Each experimental period was 21 days made up of 5 days adaptation, 11 days on feed and a 5 day total fecal collection. Indirect methods for estimating small intestinal starch digestion (glycemic response) and changes in the hindgut environment (fecal pH and acid concentrations) were used due to the use of non-surgically modified experimental animals. Mean total tract starch digestibility for all diets was high, control 92.2±4.9, cracked corn 96.6±1.0, steam flaked corn 99.2±0.4 and corn germ dehydrated 98.8±0.4 % (P>0.05). The process of steam flaking compared to cracking or dry corn milling resulted in a greater area under the blood glucose time curve in response to 1kg of corn treatment meal, suggesting increased pre-cecal starch availability. No statistical differences were observed on an equal starch basis between the three corn products (P>0.05). Cracked corn significantly lowered fecal pH compared to the control and corn germ dehydrated diets (P0.05) when comparing the control diet and the combined diets (control diet plus processed corn) and the three individual corn ingredients by the difference method. Even though mean digestibility of fiber fractions were not affected by diet, individual horse data suggests that negative impacts on fiber fraction digestion occurred. Surprisingly, the steam flaked diet did not appear to act as a positive control in limiting changes in fermentation kinetics when fed at this intake level. The process of steam flaking improves small intestinal starch availability but the reduction in particle size may increase the rate of microbial fermentation prompting the development of acidosis. The study findings suggest the corn germ dehydrated product to be a good feedstuff for horses requiring additional calories and high feed intakes. The DE value is comparable to steam flaked corn, without the negative impacts observed on fecal fermentation end products.

There is growing demand for functional foods and ingredients as a result of their health-promoting properties. In this work, the potential of common buckwheat flour (Supreme) and bran (Farinetta) in improving upon the phenolic and antioxidant properties of durum spaghetti was investigated. The effects of processing and cooking on these properties were also studied in addition to the cooking quality and carbohydrate digestibility of spaghetti products. Among uncooked spaghetti samples, there were huge increments of between 114 and 522% for TPC, 50 and 242% for TFC, 359 and 1000% for DPPH antioxidant activity, and 101 and 197% for ORAC values of the experimental spaghetti samples over the control. Farinetta contributed more phenolic and antioxidant compounds than Supreme flour. Processing resulted in losses ranging from 1.2 to 33.7% in TFC and 42.0 to 55.3% in DPPH antioxidant activity. Cooking also resulted in significant losses (p < 0.05) of up to 39% in TPC, 40% in DPPH antioxidant activity, 22% in rutin content, and 55% in TFC in experimental samples. Cooking losses of up to 8.82% were recorded for the experimental samples and were higher in Farinetta-substituted products. These were generally higher than that of the control (6.33%). The introduction of buckwheat increased carbohydrate digestibility of products, but at the same time resulted in an overall lower release of reducing sugars after of 120 min of in vitro hydrolysis. Results show that the phenolic and antioxidant properties of durum spaghetti fortified with buckwheat milling fractions can compare favourably with those of 100% whole buckwheat pasta, and at the same time, maintain a higher cooking quality due to the presence of semolina.

The aim of this study was to determine growth responses and apparent total tract nutrient digestibility in growing pigs fed diets containing graded levels of distillers dried grains with solubles (DDGS) and to determine the effect of a multicarbohydrase enzyme (MC) supplementation on visceral organ mass and fasting whole-body oxygen consumption (FWBOC). In Experiment 1, 48 pigs (25.5 ± 0.14 kg BW) were assigned on the basis of sex and BW (2 pigs per pen) to 4 diets (6 pens per diet) based on corn-barley-soybean meal with 0, 10, 20 and 30% DDGS in a 42-d trial. Apparent total tract digestibilities (ATTD) of energy and other nutrients were determined using acid insoluble ash (AIA) as the indigestible marker. Inclusion of DDGS in the diets decreased (linear, P < 0.05) average daily gain (ADG) and tended to decrease gain to feed ratio (G:F) (linear, P = 0.067) but not average daily feed intake (ADFI) (P > 0.10); however, pigs fed the 20% DDGS diet had similar ADG as pigs fed the 0% DDGS diet. Increasing DDGS content in the diet linearly decreased (P < 0.01) the ATTD of DM, energy and CP (cubic, P < 0.05) but not (P > 0.10) P and Ca; however, ATTD of neutral detergent fiber (NDF) increased (linear, P < 0.01) when DDGS was included in the diet. In Experiment 2, 24 pigs (19.9 ± 0.46 kg BW) were randomly assigned to 3 corn-soybean meal-basal diets (8 pigs per diet): Control (C, 0% DDGS); basal diet with 30% DDGS (C+30% DDGS) or C+30% DDGS supplemented with MC (C+30% DDGS+MC). On d 15, WBOC during the 24- to 30-h postprandial period was determined using an open-circuit indirect calorimeter on 4 pigs per diet. On d 28, pigs were killed to determine visceral organ mass and intestinal morphology. There was no diet effect (P > 0.10) on final BW, FWBOC, and liver, spleen, pancreas, heart, stomach and caecum weights relative to empty BW. However, pigs fed the C and C+30% DDGS+MC had heavier (P = 0.05) empty BW compared with those fed unsupplemented 30% DDGS-containing diet. Small intestine, colon plus rectum and the portal-drained viscera (PDV) were heavier (P < 0.05) in DDGS-fed pigs compared with C; supplementing with MC substantially decreased the effect of DDGS on the weight of these visceral organs. Feeding pigs DDGS tended to decrease (P < 0.10) villous height (VH) and VH:CD in the ileum. Results show that including DDGS in grower pig diets up to 20% has no effect on performance although ATTD of energy, DM, and N may be reduced. Inclusion of DDGS at 30% increased PDV mass and reduced dressing percentage but these effects were overcome by a multicarbohydrase enzyme supplementation.

The objective of this research was to determine the effect of stage of maturity at the time of harvest for barley and oat whole-crop forage on feed intake, ruminal fermentation and digestibility, and the impact forage allocation has on intake and ruminal fermentation. In the first 2 studies, whole-crop barley (Study 1; c.v. CDC Cowboy) and oat (Study 2; c.v. CDC Weaver) forage were harvested at the late milk (LM), hard dough (HD) and ripe (RP) stages and offered ad libitum to ruminally cannulated heifers. Diets were supplemented in an attempt to balance crude protein (CP) among treatments. Heifer performance, dry matter intake (DMI), ruminal fermentation parameters, ruminal digestibility, and total tract digestibility were evaluated. In Study 3, whole-crop oat (c.v. CDC Weaver) forage harvested at HD and RP was offered ad libitum to ruminally cannulated heifers in either daily (1-D) or 3 d (3-D) allocations. Dry matter intake and ruminal fermentation parameters were measured. In Study 1, harvest maturity of barley did not affect DMI (P = 0.70; average 5.4 kg/d) or average daily gain (ADG; P = 0.64). Total tract digestibility was decreased for barley harvested at HD (P = 0.003), but harvest maturity did not affect daily digestible energy (DE) intake (P = 0.52). Minimum ruminal pH for heifers fed the barley forage was lowest for LM (6.09), intermediate for RP (6.13), and greatest for HD (6.25; P = 0.016). Total short chain fatty acid (SCFA) concentrations were not affected by harvest maturity (P = 0.36). In Study 2, harvest maturity of whole-crop oat did not affect DMI (P = 0.26; average 8.1 kg/d) or ADG (P = 0.52). There were no effects of harvest maturity of oat forage on total tract digestibility (P = 0.78) or daily DE intake (P = 0.68). The minimum ruminal pH from heifers fed oat forage was lowest for HD (5.84; P = 0.012), intermediate for RP (5.94) and greatest for LM (5.99). There was no effect of harvest maturity of oat forage on total SCFA concentrations (P = 0.21). The quantity of forage allocation (Study 3) had no effect on total or forage DMI over a 3-d duration (P ≥ 0.47). Throughout the 3-d feeding period, 3-D allocated heifers had a reduction in the area pH was under 5.8 (214.4, 79.5 and 10.9 pH × min/d, for d 1, 2 and 3, respectively; P = 0.003). Total SCFA concentrations were not affected by forage allocation or harvest maturity (P ≥ 0.14), however there was an interaction of forage allocation and day in the feeding cycle (P = 0.046). Heifers allocated 1-D had no change iii in total SCFA concentration over the 3-d feeding period (averaged 122 mM), but 3-D allocation had elevated concentrations on d 1 (138 mM) intermediate on d 2 (135 mM) and decreased on d 3 (117 mM). These data suggest that harvesting barley and oat at the HD stage improves DM yield without negatively affecting cattle DMI and ADG. These data also suggest that providing 3-d allocations of forage does not affect DMI, but can increase daily fluctuations of ruminal pH and ruminal SCFA concentrations.

The objectives of this study were to characterize residual feed intake (RFI) in growing bulls and heifers and in mid-gestation females to examine relationships with performance, body composition, feeding behavior, digestibility (DMD) and heart rate (HR) and evaluate the impact of RFI on bull fertility and cow forage utilization. Additionally, use of the n-alkane method to predict individual animal variations in intake was investigated. To accomplish these objectives, multiple RFI studies were conducted. In all studies RFI was computed as the difference between actual and expected DMI from linear regression of DMI on mid-test metabolic BW and ADG. To evaluate phenotypic relationships between feed efficiency, scrotal circumference (SC) and semen-quality an experiment was conducted with yearling bulls (N=204). Residual feed intake was not correlated with BW and ADG, but was positively associated with 12th-rib back fat (BF) such that the more efficient bulls were leaner. Bulls with low RFI had similar SC and progressive motility of sperm compared to high-RFI bulls. However percent normal sperm were weakly associated with RFI in a negative manner. To examine phenotypic relationships between heifer postweaning RFI, and performance, efficiency, HR, and DMD of mid-gestation cows, RFI was measured in growing Bonsmara heifers (N=175). Forty-eight heifers with divergent RFI were retained for breeding. Subsequently, intake, performance and feeding behavior was measured on mid-gestation females. Pregnant females classified as having low postweaning RFI continued to consume 22% less feed, spent 25% less time eating, and had 7% lower HR while maintaining similar BW, ADG and body composition compared to high RFI females. A moderate association between RFI in growing heifers and subsequent efficiency of forage utilization in pregnant cows was found. Growing heifers identified as efficient had greater DMD, however DMD in mature cows was similar between RFI groups. The n-alkane method of predicting intake detected differences in intake between divergent RFI groups in mid-gestation females. Results from this study indicate that inclusion of RFI as a component of a multi-trait selection program will improve feed efficiency of growing animals and mid-gestation females with minimal impacts on growth, body composition, and fertility traits.

Diss. (sammanfattning). Uppsala : Sveriges lantbruksuniv., 2003. / Härtill 4 uppsatser.