Particle size distribution of diet, feces, and change from diet to feces, as well as apparent digestibility (aDig, %) of selected nutrients, and novel fecal microbiome identification of mature female leopard tortoises (Stigmochelys pardalis, n = 16) fed exclusively one of three, nutritionally complete, pelleted diets were evaluated in a blind, complete randomized design study. Two diets included insoluble fiber (powdered cellulose) consisting of either 2.0 mm or 0.2 mm length. Insoluble fiber provides nutritional and physical benefits to both the animal host and the microorganisms that inhabit the gastrointestinal tract. Insoluble fiber length was used as a means of evaluating a physically effective fiber (peNDF) definition for hindgut-fermenting vertebrates. Numerical trends of each diet particle size distribution indicated a greater amount of particle recovery on the 2.0 mm sieve for the 2.0 mm diet, and a greater particle recovery on the 0.125 mm sieve for the 0.2 mm diet, both as expected based on the added fiber lengths. Fecal particle size distributions were not different between diets, however, distributions of the change in particle size from diet to feces were different between diets. Similar fecal particle size distributions across diets suggests both cellulose lengths are below the peNDF threshold of the leopard tortoise. Apparent digestibility (aDig, %) of dry matter (DM) and organic matter (OM) was not different based on diet, method, or a diet and method interaction; aDig (%) of neutral detergent fiber (aNDF) and sequential acid detergent fiber (sADF) was different based only on diet. These results suggest that while aDig (%) of OM did not change, the source of OM digestibility shifted, as both aNDF and sADF digestibility increased with the cellulose-added diets compared to the control diet. An increase in insoluble fiber digestibility suggests an "effectiveness" of the cellulose lengths. At both bacterial phyla and genera levels, fecal microbiomes were more similar between tortoises fed the cellulose-added diets versus the control diet, suggesting that the hindgut microbial communities adjusted in the hindgut of the tortoises fed the cellulose-added diets by shifting proportions of microbes, based on their role in the hindgut (i.e., cellulose digestion), to accommodate for the addition of cellulose in the two treatment diets. This may explain the similarity among fecal particle size distributions, and suggests that adaptability of the hindgut microbial communities should be considered when defining peNDF for hindgut-fermenting vertebrates.

No description available.

<p> Protein digestibility, a function of the source of amino acids consumed, can differentially affect postprandial protein anabolism at rest. We investigated the effect of ingesting whey and casein proteins, in isolation and in combination, after an acute bout of unilateral resistance exercise on muscle protein synthesis in eight healthy resistance trained men (24.4 ± 4.8 yr; 177.4 ± 4.2 cm; 85.5 ± 14.8 kg; means± SD). On three occasions, participants performed a unilateral bout of resistance exercise following which they consumed a drink containing whey, whey and casein (1:1), or casein protein. Each drink provided 10 g of essential amino acids. Mixed muscle protein fractional synthetic rate (FSR) was determined by pulse-tracer injections of L-[ring-2H5]phenylalanine and L-[15N]phenylalanine 120-180 min after protein ingestion. The pattern of amino acid appearance in the blood after consuming the protein drinks was not different. Consequently, while consumption of the protein drinks stimulated a larger increase in FSR in the exercised leg compared to the rested leg (p < 0.05), there were no differences between the drinks. Thus, while the source of amino acids may affect protein turnover at rest, this effect is not apparent after resistance exercise. Therefore, we conclude that the ingestion of whey and casein proteins, in isolation or combination, stimulates mixed muscle protein synthesis to similar degrees after an acute bout of resistance exercise.</p> / Thesis / Master of Science (MSc)

For years, bear hunters have provided an unknown amount of food to black bears <i>(Ursus americanus)</i> in Virginia, supplementing their natural food supply. Possible effects of feeding bears can be negative, such as food conditioning and habituation to people, or positive, such as enhanced or sustained reproductive rates, especially in years of mast crop failure. In July 1999, the Virginia Department of Game and Inland Fisheries (VDGIF) adopted a regulation recommendation that prohibited the feeding of wildlife on national forest and department-owned lands. We mailed a survey to all members of the Virginia Bear Hunters Association (VBHA, n = 459) to determine the amount of food provided to bears by bear hunters in Virginia between 1 July 1998 and 30 June 1999. Survey response rate was 52%. One hundred thirteen of 238 (47.5%) survey respondents spent over $18,000 on supplemental food in one year, averaging $163/person. One hundred twenty-eight respondents reported cumulatively providing nearly 3 million kilograms of food to bears between 1 July 1998 and 30 June 1999. Whole-shelled corn, pastries, and grease accounted for 58% of the total food by weight; however, whole-shelled corn, pastries, and bread were the 3 most common foods offered. Feeding occurred in 25 counties in Virginia, primarily during July, August, and September. Rockingham County had the highest proportion of feeders (47%), followed by Giles (15%), Augusta (14%), Craig (9%) and Montgomery (9%) Counties. Accordingly, Rockingham County received the highest proportion of food (42%), followed by Craig (8%), Giles (7%), Montgomery (6%), and Tazewell (6%) Counties. The low survey response rate, coupled with the fact that 48% of sampled nonrespondents fed bears, suggests that the total amount of annual feeding in Virginia may exceed the total determined during this study. However, the possibility of an avidity bias, in which a higher response by the more avid feeders would erroneously inflate a total estimate extrapolated to include feeding by nonrespondents, cannot be eliminated. Little work has been done pertaining to digestibilities of black bear foods, particularly those in the eastern United States. We determined digestibilities for several important eastern black bear foods, including northern red oak <i>(Quercus rubra)</i>, white oak <i>(Q. alba)</i>, and chestnut oak acorns <i>(Q. prinus)</i>, squawroot <i>(Conopholis americana)</i>, high-protein dogfood, shelled corn, and doughnuts. All diets were evaluated for nutrient content as well as percent dry matter digestibility of crude protein, ether extract (a measure of fat), and gross energy. Diets we suspected were high in fiber were additionally evaluated for neutral detergent fiber or acid detergent fiber content and digestibility. Feeding trials were conducted with 1 male and 4 female captive bears during fall 1998, and 5 female captive bears during fall 1999, at the Center for Ursid Research, Blacksburg, Virginia. Acorns and squawroot were high in fiber (45-62%) and moderate to low in protein (5-7%). Fat content was high in doughnuts (24.7) and northern red oak acorns (12%), moderate in dogfood (8.2%) and white oak acorns (4.7%), and relatively low in shelled corn, chestnut oak acorns, and squawroot (1.3-3.5%). Crude protein was high in dogfood (29%) and moderate in all other diets (4.7-8.8%). Neutral detergent fiber content was high in squawroot and all acorn types (45-62.4%). Acid detergent fiber was high in squawroot (47%) and moderate in dogfood (9%). In 1998, crude protein digestibility was high in doughnuts (86%), moderate in shelled corn and white oak acorns (50-64%), and negligible in northern red oak acorns (-39%). Ether extract digestibility was high in doughnuts, red oak acorns, and white oak acorns (80-97%), and moderate in shelled corn (67%). Fiber digestibility was tested only on northern red oak and white oak acorns, and was moderate (62% and 68%, respectively). In 1999, crude protein digestibility was high in dogfood, dogfood mixed with squawroot, and doughnuts (75-85%); moderate in shelled corn, squawroot, and white oak acorns (43-58%); and low to negligible in chestnut oak and northern red oak acorns (-13-6%). Ether extract digestibility was moderate in shelled corn (64%) and squawroot (60%), and high in all other diets (79-97%). Neutral detergent fiber digestibility was moderately high in all acorn types (54-71%). Acid detergent fiber digestibility was moderate for dogfood (66%), and associative effects occurred between the fiber in squawroot and dogfood, resulting in negative fiber digestibility in squawroot determined by difference (-19%). A luxury not always realized in wildlife management is the ability to investigate possible effects of management or policy changes prior to their employment. The amount of food provided to bears by bear hunters in Virginia may have been more substantial than previously believed, and likely provided bears with a high energy, stable food source that supplemented their natural food supply. We did not have the opportunity to study the effects of removing that food source on public lands prior to the regulation change; however, the opportunistic feeding strategy of bears, coupled with sufficient mast production at the time of the regulation change, likely softened any negative effects that may have occurred as a result of the removal of supplemental food as a regular food source for some bears. / Master of Science

Insect herbivory on forest canopies strongly affects ecosystem nutrient cycling and availability in a variety of ways, e.g. by changing the quantity, quality and timing of nutrient input to forest soils. A qualitative method for measurements of ingestion, egestion and exuviation rates of the insect Chrysomela tremulae on leaves of the hybrid Populus tremula x tremuloides were tested in this study with the aim to detect differences in relative nutrient cycling efficiencies. The assimilation efficiency (AD), efficiency of conversion of digested food (ECD) and efficiency of conversion of ingested food (ECI) increased from 1st, through 2nd and 3rd instar larvae with generally higher efficiencies for nitrogen than carbon. Effects on nutrient limitations for the insect were also tested by increasing the C:N ratio of insect diet. A carbohydrate solution was painted onto leaves which resulted in a significant increase in C:N (p&lt;0.0001). This lead to a trend of lengthened developmental time for each ontogenetic stage, as well as higher ingestion rate and lower egestion- and exuviation rates. However, a different method of increasing the C:N ratio is recommended in future experiments since the leaves never truly absorbed the solution.

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / The objective of this research was to evaluate of three grazing systems (GS) with Elephant grass (EG) + Italian ryegrass (IR) + spontaneous growing species (SGS); EG + IR + SGS + Forage peanut (FP); and EG + IR + SGS + Red clover (RC), in order to use the area in rotational grazing during all agricultural year. EG was planted in rows with a distance of 4 m each one of them. In the cool-season, IR was sowed between rows of EG; RC was sowed and the FP who has found established since 2006 was preserved on respectively GS. Experimental design was completely randomized with three treatments (GS), two replicates (paddocks) and independent evaluations (grazing cycles). For evaluation, were used lactating Holstein cows receiving 1% of BW day-1 feed supplement concentrate. The pre and post forage mass parameters, botanical and structural composition, forage production and stocking rate were evaluated. Samples were collected by the handplucking method to analyze the organic matter, mineral matter, crude protein (CP), neutral detergent fiber (NDF), in situ organic matter digestibility (ISOMD), in situ dry matter digestibility (ISDMD) of forage. Eight grazing cycle were performed during the experimental period (357 days). The values of forage production and stocking rate were 15.03, 16.33, 17.03 t ha-1 and 3.57, 3.52 and 3.65 animal unit ha-1, respectively grazing systems. Grazing systems involving grasses and forage legumes in different cycles provide use of the area during the agricultural year in rotational grazing with dairy cattle. SGS increased significantly (P≤0.05) over in GS without forage legume. Higher value of CP, ISOMD and lower of NDF for GS mixed with forage legumes. Considering the herbage mass, stocking rate and nutritive value, the pastures mixed to forage legumes showed better performance. / O objetivo desta pesquisa foi avaliar três sistemas forrageiros (SF) com capim elefante (CE) + azevém (AZ) + espécies de crescimento espontâneo (ECE); CE + AZ + ECE + amendoim forrageiro (AM); e CE + AZ + ECE + trevo vermelho (TV), com o intuito de utilização da área em pastejo rotativo durante todo o ano agrícola. O CE foi estabelecido em linhas afastadas a cada 4 m. No período hibernal fez-se o estabelecimento do AZ entre as linhas do CE; o TV foi semeado e o AM que já se encontrava estabelecido desde 2006, foi preservado, considerando os respectivos tratamentos. O delineamento experimental foi o inteiramente casualizado, com três tratamentos (SF), duas repetições (piquetes) e avaliações independentes (ciclos de pastejo). Para avaliação foram utilizadas vacas da raça Holandesa em lactação, que receberam suplementação alimentar com concentrado à razão de 1% do peso corporal dia-1. Foram avaliados parâmetros de massa de forragem pré e pós pastejo, composições botânica e estrutural, produção de forragem e taxa de lotação. Para analisar a matéria orgânica, matéria mineral, a fibra em detergente neutro (FDN), a proteína bruta (PB), a digestibilidade in situ da matéria seca (DISMS) e a digestibilidade in situ da matéria orgânica (DISMO) da forragem, foram coletadas amostras de pastejo simulado. Durante o período experimental (357 dias) foram efetuados oito ciclos de pastejo. Os valores de produção de forragem e de taxa de lotação foram de 15,03; 16,33; 17,03 t ha-1 e 3,57; 3,52 e 3,65 UA ha-1, respectivamente para os sistemas forrageiros. Sistemas forrageiros, envolvendo gramíneas e leguminosas de diferentes ciclos, proporcionam a utilização da área durante todo o ano agrícola em pastejo rotativo com bovinos leiteiros. Houve aumento significativo (P≤0,05) para ECE na pastagem sem leguminosa. Foram observados maiores valores de PB, DISMO e menores de FDN para os SF consorciados com leguminosas. Considerando a massa de forragem, a taxa de lotação e o valor nutritivo, as pastagens consorciadas com leguminosas forrageiras apresentaram melhor desempenho.

Cette étude a été menée dans le but d’explorer les nouvelles sources de protéines à valeur nutraceutique. Les graines de Ricinodendron heudelotii (Bail. Pierre ex Pax) et de Tetracarpidium conophorum (Müll. Arg) ont d’abord été cuites dans de l’eau bouillante pendant 90 et 30 min qui sont respectivement leurs temps optimums de cuisson. Après délipidation et tamisage des tourteaux, la fraction 400 - 500 µm s’est révélée la plus représentative avec plus de 70 % et riche en azote protéique (6–7% MS). Les concentrats et les isolats protéiques ont été préparés à partir des tourteaux respectivement dans l’eau distillée à pH 4,5 et dans une solution de NaOH à 0,2 % (R. heudelotii), une solution de NaCl 0,6 M (T. conophorum) à pH 11. Ces concentrats (65 – 75 % MS de protéines) et ces isolats protéiques (81 – 92 % MS de protéines) ont une composition physico-chimique différente (P < 0,05) de celle des tourteaux. Pour les deux Euphorbiacées, les capacités de rétention d’eau (367 – 467 g / 100 g d’échantillon), de rétention d’huile (256 – 410 g / 100 g d’échantillon) et moussante (68 – 71 %) sont maximales dans les isolats protéiques tandis que les capacités gélifiante (6 – 14 %) et émulsifiante (63 – 87 %) le sont dans les concentrats protéiques. Les teneurs en acides aminés essentiels des tourteaux de R. heudelotii et de T. conophorum sont comparables à celle de la protéine de référence. L’étude de la digestibilité enzymatique in vitro a montré que l’azote libéré après 6 h est supérieur à 90 % dans les concentrats et les isolats protéiques. La digestibilité protéique in vivo indique que le gain de poids des rats mâles âgés de 21 ± 3 jours durant 15 jours d’expérimentation ainsi que les paramètres de rétention azotée sont plus importants avec les régimes à base de l’aliment de référence (caséine) et du tourteau de T. conophorum. Les valeurs corrigées des paramètres de digestibilité par l’indice chimique des acides aminés laissent apparaître que le tourteau de T. conophorum renferme les protéines de très bonne qualité nutritionnelle, autant que la caséine / This study was conducted in order to look for alternative sources of proteins having nutraceutic value. The grains of Ricinodendron heudelotii (Bail.) and Tetracarpidium conophorum (Müll. Arg) were first cooked in boiled water at their optimal cooking time for 90 and 30 min respectively. After defating, sieving of the defatted cakes showed that samples with a granulometry of 400 - 500 µm were most representative (more than 70%), containing more proteic nitrogen (6–7 %). Protein concentrates and protein isolates were prepared from defatted cakes respectively in distilled water at pH 4.5 and in NaOH 0.2% (R. heudelotii) and NaCl 0.6M (T. conophorum) at pH 11. Physico-chemical properties of protein concentrates (65 – 75 % of proteins) and protein isolates (81–92 % of proteins) were different from those of the defatted cakes. Water holding (367 – 467 g / 100 g of sample), oil holding (256 – 410 g / 100 g of sample) and foaming capacities (68 – 71 %) were highest with protein isolates whereas gelling (6 – 14 %) and emulsion capacities (63 – 87 %) were highest with concentrates. The amounts of essential amino acids in both defatted flours were comparable to the value in FAO / WHO (2007) scoring pattern. Nitrogen liberated after 6 h of enzymatic digestibility was more than 90 % both in the proteins concentrates and isolates. In vivo studies carried out on 21 ± 3 days old Sprague Dawley male rats for 15 days showed that gain of weight and nitrogen retention parameters were higher for rats that consumed casein and T. conophorum defatted cake. Corrected values of nitrogen digestibility of the analysed samples showed that T. conophorum defatted cake contains protein source with good nutritional quality

Thesis (MScAgric (Animal Sciences))--University of Stellenbosch, 2010. / ENGLISH ABSTRACT: The purpose of this study was to investigate the variation that exists between maize samples regarding particle size separation, in vitro fermentation kinetics and in vitro dry matter (DM) disappearance. A second objective was to quantify possible relationships between the Roff Milling Index (RMI) of maize and any of the measured in vitro parameters. Three trials were conducted: a particle size distribution trial, a gas production trial and an in vitro DM degradability and starch disappearance trial. Overall, nine maize samples, which differed in terms of cultivar and endosperm type, were collected from different origins for the study. The samples were selected in terms of their Milling Index (MI). Three of the nine samples had a high MI that ranged between 109 and 118, three had a low MI that ranged between 67 and 71 and the other three samples had a medium MI that ranged between 85 and 92. Although the MI is not a direct indication of the hardness or softness of the endosperm, it was believed to be indirectly associated with vitreousness. In the first trial, the different maize samples were milled through a 1 mm screen and sieved through a series of three sieves 150, 125 and 106 μm, respectively. It was found that RMI was not a reliable indicator to predict particle size distribution, especially in terms of the coarse (>150 μm) and very fine (<106 μm) particles. In the gas production trial, the nine different maize samples were subjected to a gas production system for a duration of 48 hours. Here gas production and rate of gas production of the different maize types in buffered rumen liquor were measured during incubation. After fitting the gas volume data to the respective models, the non-linear parameters b, c and L were subjected to a main effects ANOVA with the aid of Statistica, version 9 (2009). Main effects were treatment and repetition. Means were separated by means of a Scheffé test and significance was declared at P < 0.05. The results were compared to the RMI of the different maize types and it was concluded that RMI was not a reliable predictor of gas production or rate of gas production of different maize types. In the third trial, in vitro DM degradability and starch disappearance of the different maize types were measured. In vitro DM degradability was conducted in the Ankom DAISYII incubator apparatus and the incubation times were 0, 2, 4, 8, 12 and 24 hours. Starch disappearance was measured on residues of the samples incubated for 0, 2 and 4 hours. After fitting the DM disappearance data to the respective models, the non-linear parameters a, b, c and L were subjected to a main effects ANOVA with the aid of Statistica, version 9 (2009). Main effects were treatment and repetition. Means were separated by means of a Scheffé test and significance was declared at P<0.05. The results indicated variation between maize samples, especially in terms of the a-, b- and L-values. The RMI did not appear to be a reliable predictor of digestibility parameters. / AFRIKAANSE OPSOMMING: Die doel van hierdie studie was om die variasie tussen mieliemonsters te ondersoek ten opsigte van die skeiding van partikelgroottes, in vitro-fermentasiekinetika en in vitro-droëmateriaalverdwyning. ‘n Tweede doel was om te bepaal of daar moontlike verwantskappe tussen die Roff Milling Index (RMI) van mielies en enige van die ander in vitro-parameters bestaan. Drie proewe is gedoen: verspreiding van partikelgrootte, ‘n gasproduksieproef en ‘n droëmateriaal degradeerbaarheid- en stysel verdwyningsproef. Nege mieliemonsters, wat van mekaar verskil ten opsigte van kultivar en endospermtipe, is van verskillende lokaliteite versamel. Die monsters is gekies in terme van hul maal-indeks (MI). Drie van die nege monsters het ‘n hoë MI gehad wat gewissel het tussen 109 en 118, drie het ‘n lae MI gehad wat gewissel het tussen 67 en 71 en die ander drie monsters het ‘n medium MI gehad wat gewissel het tussen 85 en 92. Alhoewel die MI waardes nie ‘n direkte indikasie van ‘n endosperm se hardheid- of sagtheidsgraad is nie, is dit aanvaar dat daar ‘n indirekte verwantskap tussen MI en glasagtigheid van die mielie bestaan. In die eerste proef is die nege verskillende mieliemonsters deur ‘n 1 mm sif gemaal en daarna deur ‘n reeks van drie siwwe met groottes van onderskeidelik 150, 125 en 106 μm gesif. Daar is bevind dat die RMI nie ‘n betroubare voorspeller is om partikelgrootte-verspreiding aan te dui nie, veral nie ten opsigte van growwe (> 150 μm) en baie fyn (< 106 μm) patikels nie. Tydens die gasproduksieproef is die nege mieliemonsters vir 48 ure blootgestel aan ‘n gasproduksiesisteem, waar gasdruk outomaties aangeteken is. Gasproduksie en tempo van gasproduksie van die verskillende mieliemonsters is gemeet en aangeteken gedurende inkubasie met ‘n gebufferde rumenvloeistofmedium. Nadat die gasvolumedata met behulp van relevante modelle gepas is, is die nie-linêre parameters b, c en L onderwerp aan ‘n hoof-effek ANOVA met die gebruik van Statistica weergawe 9 (2009). Hoof-effekte was behandeling en herhaling. Gemiddeldes is deur ‘n Scheffé-toets geskei en betekenisvolheid is verklaar by P<0.05. Die resultate verkry is vergelyk met die RMI van die verskillende mielietipes. Die gevolgtrekking is gemaak dat Roff MI nie ‘n betroubare voorspeller van totale gasproduksie of gasproduksietempo is nie. Tydens die derde proef is droëmateriaaldegradeerbaarheid en styselverdwyning van die verskillende mielietipes bepaal. In vitro droëmateriaal (DM) degradeerbaarheid is gedoen in die Ankom DAISYII inkubator met inkubasietye van 0, 2, 4, 8, 12 en 24 ure. Styselverdwyning is bepaal deur styselanalises op die residue van die monsters wat geïnkubeer is vir 0, 2 en 4 ure. Nadat die DM-degradeerbaarheid met behulp van relevante modelle gepas is, is die nie-lineêre parameters a, b, c en L onderwerp aan ‘n hoof-effek ANOVA met die gebruik van Statistica weergawe 9 (2009). Hoof-effekte was behandeling en herhaling. Gemiddeldes is deur ‘n Scheffé toets geskei en die betekenisvolheid is verklaar by P<0.05. Die resultate het aangedui dat daar groot variasie tussen mielies bestaan, veral ten opsigte van die a-, b- en L-waardes. Dit het verder geblyk dat die RMI van die verskillende mielietipes nie ‘n betroubare voorspeller van DM-degradeerbaarheid was nie.

Thesis (PhD(Agric))--Stellenbosch University, 2011. / ENGLISH ABSTRACT: Exogenous fibrolytic enzymes (EFE) as additives in ruminant feeds are being researched worldwide. Promising effects on dry matter intake (DMI), digestibility and production in especially dairy cows, but also feedlot steers and even sheep have been observed. However, lack of or negative effects are also reported and the need arises for clarity on the mode-of-action of EFE. Forages are characterised as being highly heterogenic and contain varying concentrations of fibre. The fibre, in turn, varies greatly in digestibility, due to the chemical as well as anatomical build-up of this complex carbohydrate. Fibre, however, presents a major source of potential energy for ruminant animals and EFE is a viable option to increase the digestibility of forages. Therefore, a study with the aim of establishing whether EFE can affect the digestibility of forages, how it affects the digestibility and the clarification of the mode-of-action was drafted. From the literature, the first objective was readily attained and clear indications exist that EFE can indeed improve animal performance when their diets are treated with such enzymes. From the current study, it was shown that EFE can alter the rate and extent of gas production of certain forages (lucerne, kikuyu and weeping love grass) and also improve the in vitro digestibility thereof (P < 0.05). This is in agreement with other research findings and it was concluded that these effects were likely exerted during the early stages of digestion. A complete feed for sheep, when treated with the EFE, showed positive effects on the in sacco digestibility, as well as on the digestion kinetics of the feed (P < 0.05). The in vitro digestibility of the complete feed was also improved due to EFE treatment (P < 0.05). The observations on in vitro digestibility were less marked when a purified xylanase, obtained from the partial purification of the EFE cocktail, was used as the sole fibrolytic enzyme treatment. It is apparent, therefore, that enzyme specificity plays a major role in obtaining positive effects on digestibility of forages and feeds. In agreement with the literature, it is proposed that the approach to improve the digestibility of forages should be to use EFE cocktails containing various enzymes, matching the complexity of the substrate. The major aim of the study was, however, an in depth investigation of the mode-of-action of EFE. This aim was approached by observing changes in plant tissue material at the histological level upon treatment with EFE and incubation in buffered rumen fluid. Results showed that EFE had subtle, yet significant effects on cell wall material for the various tissues studied (P < 0.05). The major effect observed here was that EFE had a thinning effect on the cell wall thickness (P < 0.05). It was deduced that as EFE affected the cell wall of the plant material, earlier access by microorganisms could be achieved. Also, nutrients caught in the cell wall matrix could then be released for digestion. Therefore, observations that EFE increases the rate of digestion, as well as the extent of digestion of not only fibre, but also protein, were explained by the enzyme’s action on cell wall material. It was concluded that there is definite merit in the use of EFE to improve the digestibility of ruminant feeds and that this is partly related to effects on the cell walls of the forages. The effects can be expected to occur during the early stages of digestion, thereby potentially increasing the passage rate of digesta from the rumen. Additionally, the effect of the EFE is not limited to fibre and increased digestibility of all nutrients can be expected, thereby increasing the overall digestibility of the feed. Future research should further elucidate the mode-of-action of EFE using advanced technologies routinely employed in the plant sciences. Additionally, the main potential advantage of EFE treatment lies in improving the digestibility of poor quality roughages. Unfortunately, this is an area where limited positive effects are observed and in depth investigations should be undertaken to classify the specificity and optimum conditions of EFE to better match the complexity of the substrate being treated. / AFRIKAANSE OPSOMMING: Eksogene fibrolitiese ensieme (EFE) word tans wêreldwyd ondersoek vir die gebruik daarvan as voerbymiddels vir herkouers. Belowende effekte op DMI, verteerbaarheid en produksie van vernaam melkbeeste, maar ook voerkraalbeeste en selfs skape is al gerapporteer. Swak en selfs negatiewe effekte word egter ook waargeneem en daarom is ʼn deeglike ondersoek na die metode van werking van EFE van belang. Ruvoere word gekenmerk deurdat dit heterogeen van aard is en bevat variërende vlakke van vesel. Vesel maak op sy beurt ʼn wesenlike deel uit van die ruvoer, maar varieer baie in verteerbaarheid weens die chemiese sowel as anatomiese samestelling van hierdie komplekse koolhidraat. Ruvoer verteenwoordig egter ʼn goeie bron van potensiële energie vir herkouers en EFE word voorgestel as ʼn haalbare behandeling om die verteerbaarheid daarvan te verhoog. Dus is ʼn studie beplan met die doelwit om die effekte van EFE te definieer, hoe dit verteerbaarheid beïnvloed en die metode van werking daarvan te ondersoek. Vanuit die literatuur is dit duidelik dat daar wel baie positiewe effekte is waar ruvoere met EFE behandel is en dat diereproduksie wel bevoordeel word daardeur. Vanuit die studie is dit getoon dat die tempo en hoeveelheid gasproduksie van sekere ruvoere (lusern, kikuyu en oulandsgras) verbeter word deur EFE behandeling (P < 0.05). Hierdie bevinding was ondersteun deur verbeterde in vitro verteerbaarheid van die ruvoere (P < 0.05). Dit is in ooreenstemming met literatuur en die gevolgtrekking is gemaak dat hierdie effekte tydens die vroeëre stadia van vertering verwag kan word. ʼn Volledige skaapvoer wat met EFE behandel is, het positiewe effekte op in sacco verteerbaarheid en verterings kinetika data gehad (P < 0.05). Weereens is die in vitro verteerbaarheid van die voer verbeter (P < 0.05). Waarnemings op in vitro verteerbaarheid was veel minder opvallend wanneer ʼn gesuiwerde xylanase as enigste fibrolitiese ensiem behandeling gebruik is. Dit is dus duidelik dat ensiem spesifisiteit ʼn belangrike rol speel in die verkryging van positiewe resultate in die verteerbaarheid van ruvoere en veevoere. In ooreenstemming met literatuur word dit voorgestel dat ensiemmengsels wat verskeie ensieme bevat as EFE gebruik behoort te word ten einde aan die kompleksiteit van die substraat te voldoen. Die hoof doelwit van die studie was egter ʼn indiepte ondersoek na die metode van werking van EFE. Hierdie doelwit is benader deur die effekte van EFE op selwand strukture van plantmateriaal op ʼn histologiese vlak te ondersoek. Die ruvoere was vooraf met EFE behandel en in vitro geïnkubeer in rumen vloeistof. Die resultate het getoon dat EFE ʼn matige, dog betekenisvolle effek op die selwand materiaal van die onderskeie weefsels gehad het (P < 0.05). Die belangrikste waargeneemde effek was dat EFE ʼn verdunningseffek op die selwande gehad het. Dit is afgelei dat as EFE die selwand kan beïnvloed, mikro-organismes vroeër toegang tot die inhoud kan kry. Verder, nutriënte vasgevang in die selwand matriks raak ook beskikbaar vir vertering. Hierdie afleiding en die effek van EFE op selwande verklaar waarnemings dat EFE die tempo van vertering sowel as die vlak van vertering van nie net vesel, maar ook proteïen kan bevoordeel. Die gevolgtrekking is gemaak dat daar definitiewe meriete is in die gebruik van EFE om die verteerbaarheid van herkouervoere te verbeter en dat dit verband hou met die ensiem se werking op selwande van die ruvoere. Die effekte kan verwag word tydens die vroeë stadia van vertering om dus deurvloeitempo van digesta te verbeter. Die effek van die EFE is verder nie beperk tot vesel nie, maar positiewe effekte op ander nutriënte kan verwag word en vervolgens ʼn algehele verhoging in die verteerbaarheid van die voer. Navorsing behoort in die toekoms verder die metode van werking van EFE te ondersoek deur gebruik te maak van gevorderde tegnologie wat alledaags gebruik word in die Plantwetenskappe. Die belowendste aanwending van EFE lê in die verbetering in vertering van swak kwaliteit ruvoere. Dit is ongelukkig juis hier waar min positiewe resultate gerapporteer word en indiepte navorsing moet onderneem word om ensiem spesifisiteit en optimum kondisies te definieer sodat EFE beter opgewasse is teen die kompleksiteit van die substraat.

The effects of oxidation by sodium hypochlorite (0, 0.8, 2, and 5%, NaOCl), the presence of endogenous proteins, and amylose content on waxy and common rice flours (WF, CF) and starches (WS, CS) were investigated in terms of in vitro starch digestibility, morphology and surface properties, and thermal and rheological characteristics. The concentration of NaOCl had an effect on all the samples including WF, CF, WS, and CS. The carbonyl and carboxyl group contents increased up to 25 and 10 folds (P < 0.05) of oxidized starches (WS, CS), respectively. Only mild oxidation (P < 0.05) occurred in flours (WF, WS). In addition, endogenous proteins were oxidized according to amino acid analysis and SDS–PAGE results. Glu+Gln, Gly, His, Arg, Tyr, and Lys were more sensitive to NaOCl oxidation. Disulfide bonds, hydrophobic force, and hydrogen bonds were involved in protein polymerization after NaOCl oxidative modification. In granular state, the in vitro starch digestibility of WF, WS, and CS decreased by 5% NaOCl oxidation. After gelatinization, only 2 and 5% oxidized WS had lower digestibility. Scanning electron microscopy and confocal laser scanning microscopy further demonstrated that protein existed on the surface of starch granules and had aggregation by oxidation. X-ray diffraction patterns showed the crystallinity of 5% oxidized flours and starches was reduced compared with all their non-oxidized samples. Thermal and rheological properties were analyzed by differential scanning calorimetry and rheometer, respectively. Starch gelatinization peak temperature of flours (WF, RF) was increased by 3 °C, but starches (WS, CS) had a significantly decrease by 8 °C. Viscoelastic patterns were dramatically changed by oxidation. Oxidized WF and CF had increased in both viscosity and elasticity by oxidation, whereas both WS and CS had significantly lower viscoelasticity after oxidative modification.