Thèses sur le sujet « Monogastric animals »

There is a wide interest in developing management and feeding strategies to stimulate gut development and health in monogastric animals. The ultimate aim of these strategies is to improve productivity, while minimizing the use of antibiotics and rather expensive feed ingredients: indeed, under practical conditions, animals don’t achieve the maximum of their growth performance potential. Large amounts of research have been conducted evaluating the impact of a wide range of feed ingredients and feed additives on various aspects of gut health and development in monogastric animals. The main objective of this thesis was to improve our knowledge on the properties of new additives as feeding strategy, in order to increase general health in piglets around weaning and poultry, with the aim to substitute antibiotics growth promoters. Three different trials were designed to study different strategies. In the first study proposed, the effects of plant extract administered through drinking water on post-weaning gut health of piglets were investigated. Phytogenic feed additives are plant-derived products used in animal feeding to improve the performance of agricultural livestock. The objective of the present work was to evaluate the effects of a novel plant extract derived from common food plants on performance and health of weaned piglets fed mixed diet. At weaning (24 d), a total of 144 piglets were allocated in two post-weaning rooms, using a 2x2 factorial arrangement; treatments were Plant Extracts, 0 (Control group) or 8 μl daily/piglet (PE group) and Feeding Regimen, Ad Libitum or Restricted (piglets fed from 8 AM to 8 PM). Plant Extracts were a liquid mixture administered through drinking water. Piglets were housed in pens of three; each pen represented one treatment replicate, with six pens per treatment per room. On day 9 of the trial, after an adaptation period, each piglet of room 2 was orally injected with 4 ml of a solution containing 109 cfu of the virulent E. coli 0149: F4(K88)-positive strain. Animals were weighed and growth performance were recorded weekly; fecal score was evaluated at the same time as the weighing. At 0, 14 and 35 days, fecal samples were collected for microbiological analysis, while at day 0, 6, 19 and 35, blood samples were obtained from one pig per pen. At the end of the trial (35 d), 24 animals (12 from Control groups and 12 from Plant Extract groups) among Restricted feeding piglets were selected according to their body weight and slaughtered; immediately after slaughtering, the gastro-intestinal tract was removed from each animal: the distal ileum was collected and examined to assess the ileum micro-anatomical structure, perform histometry and immunohistochemistry and determine intestinal inflammatory parameters. PE supplementation enhanced ADG during the last week of the trial (P=0.007) and reduced FCR during the second (P=0.009) and the last weeks (P=0.04), and considering the overall period (P=0.01); a lower fecal score was observed in PE piglets (P<0.01). On day 35, lower fecal E.Coli (P=0.02) and Entrobacteriaceae (P=0.009) concentrations were determined in PE animals compared to control ones. Ileum crypts from PE piglets were deeper in challenged animals in comparison with not-challenged ones (P<0.05); number of mucosal macrophages was higher in Control challenged animals (P<0.05): in particular, number of mucosal macrophages in PE challenged piglets was similar to that one identified in not challenged Controls. PE supplementation also increased GSH-Px plasma concentration at d 6 (P=0.02) and tended to lower value of MDA at day 6 (P=0.07) and to increase value of T-AOC at the end of the trial (P=0.07). Hence, our results confirmed the possible protective functional role of the plant extracts mixture after the bacterial challenge: we can postulate that the use of plant extracts may be useful in the prevention of post-weaning diarrhea with an associated improvement in performance. The aim of the second trial was to evaluate the effect of the administration of mannanooligosaccharides (MOS) on growth performance, microbial population in feces and cecum and potential alteration of intestinal histomorphometric and gene expression of some intestinal inflammatory parameters of piglets fed a low digestible diet. Forty-eight weaned piglets (6.72 ± 0.32 kg of BW, 24 d of age) were used in a 35-d experiment and randomly allotted to 2 dietary treatments: basal diet (Control) and basal diet + 0.2 % MOS. Growth performance were recorded weekly, fecal samples were collected at 0, 14 and 35 d. At the end of trial, 10 piglets from each group were slaughtered and intestinal samples were collected. Data were analysed by a General Linear Model (GLM) procedure of SAS. BW, ADG, ADFI were not influenced by MOS supplementation; FCR was lower in treated animals in the last 2 weeks (P<0.05). Mean fecal score was improved in MOS piglets (P<0.01). At the end of trial treated piglets had higher Lactobacilli fecal count (P<0.05). No difference was detected among groups for Coliforms, while lower Clostridia occurred on day 14 in MOS piglets (P<0.05). Intestinal villi height in the duodenum was higher in MOS than Control (P<0.05). MOS supplementation also led to significant increase of NO production in ileal mucosa (P<0.05); finally, MOS suppressed mRNA relative expression of pro-inflammatory genes for IL-1α, IL-1β, IL-6 and TLR2 (P<0.05), for TLR4 (P<0.01) and for TNF (P<0.001), while there was no effect on IL-10 and PPARγ expression. Results indicate that MOS supplementation improved feed efficiency and intestinal morphometry of piglets fed low digestible diet. The third study was carried out to determine the effects of a probiotic mixture containing two strains of Lactobacillus on growth performance, carcass composition, blood lipids, digestive enzyme activity and intestinal microbiota in broiler chickens. Two dietary treatments, consisting of basal diet (control) and basal diet supplemented with combination of L. farciminis and L. rhamnosus were fed to 392 one day-old Ross 708 broiler chicks for 7 weeks. Each treatment had 28 replicates of 7 broilers. The results showed that body weight gain was improved in broilers fed probiotics diet compared to controls during 0-42 d (P<0.001) but not 43-49 d of age. Probiotic fed chicks had transitorily higher serum total cholesterol (P=0.02) and high-density lipoprotein cholesterol (P<0.008) at 28 d of age. Serum total protein was higher at 28 d of age (P=0.02) and lower at 49 d of age (P=0.001) in probiotics fed chicks compared to controls. Probiotics tended to increase abdominal fat percentage at 49 d of age (P<0.10). No difference in enzyme activity of small intestine digesta was observed. Dietary probiotics markedly increased Lactobacilli (P=0.01) and total Anaerobes (P≤0.01) counts and decreased Coliform (P=0.01) and total Aerobe counts (P≤0.01) in small intestine and caecum. The overall results demonstrated that dietary inclusion of a mixture of L. farciminis and L. rhamnosus could promote the growth and positively modulate intestinal microbiota in broiler chickens.

Optimal gastrointestinal functionality and health is essential for sustainable animal production, especially considering that nowadays, the challenge in livestock sector is to maintain a high productivity and food security in a sustainable way, reducing the use of antimicrobials. Nutritional strategies that aim to improve animals’ performance preserving their intestinal health, are essential for achieving these goals. Therefore, in the present thesis, various nutritional interventions were evaluated, using short and medium chain fatty acids in particular, on the growth and intestinal well-being of pigs. The purpose of this thesis was to: 1) evaluate the effects of an innovative form of a medium chain fatty acid, lauric acid saponified with calcium, supplemented in post-weaning piglet diet on their growth and gut health and as a possible alternative to reduce the use of antibiotics; 2) asses the effectiveness of the combination of a short chain fatty acid (tributyrin) and a medium chain fatty acid (monolaurin) in post-weaning piglet diet on their growth performance and some gut health parameters; 3) evaluate the effects of lauric acid saponified with calcium administered to sows diet starting from the last 3 weeks of gestation, on sows productivity and on the growth performance and health of their offspring; 4) to assess the effect of fatty acids and different milk fractions on porcine IPEC-J2 cell line proliferation and viability. The results presented in this thesis highlight how short and medium chain fatty acids are effective candidates for improving animal health, reducing the use of antibiotics. This may contribute to the development of a more sustainable livestock production system based on the respect of animal health and the reduction of antimicrobials, as recommended by the “One Health” approach. However, further investigations are necessary to better understand the mechanisms of action, the dosage and the best forms of administration of short and medium chain fatty acids (alone or synergistically) integrated in pigs’ diets, in particular during weaning, to further improve their growth performance and gut health.

The global demand for food from animal agriculture is anticipated to nearly double by 2050. The growth in white meat (pork and poultry) production in developing countries between 1989 and 1999 has been remarkable - more than double the growth of red meat (cattle, sheep and goats). Increased production can be achieved by a combination of expansion in animal numbers and increased productivity. Higher productivity is a compound of higher offtake rates (shorter production cycles by, for example, faster fattening), and higher carcass weight or milk or egg yields. The projections show that the increase in livestock numbers will remain significant, but less so than in the past. Higher carcass weights will play a more important role in beef production, while higher offtake rates (shorter production cycles) will be more important in pig and poultry meat production. In order to increase health and feed efficiency in monogastric animals, four trials were carried out to evaluate the role of some additives used to increase health in post-weaning piglets and in poultry meat production. The aim of first study was to evaluate the effects of nucleotides administration to post-weaning piglets on ileal proinflammatory interleukin gene expression. Thirty-six weanling piglets (28 d of age, 7.85 ± 0.25 kg L.W.) were used in 28 days study. Piglets were allotted to 2 homogeneous groups (C, T) and fed the basal diet supplemented with oral nucleotides (UMP 88.05%, GMP 5.51%, AMP 3.82%, CMP 1.94% and IMP 0.68%; 0.8 g/piglet/day in 2.1 ml water solution) or saline. On day 14 both experimental groups were challenged with 1x109 CFU/g E. coli 0149:F4(K88). Growth performance and faecal score were evaluated weekly, while blood samples for immunological serum parameters, Fe and Vitamin B12 serum content were collected on days 0, 13, 18 and 26. Proinflammatory IL1a, IL1b, IL6, IL10, and TNF, TLR2 and TLR4 gene expression in ileal Peyer patches were evaluated at slaughtering after individual tissue sample collection by RT-PCR and β-actin as housekeeping gene. Growth performances were not affected by dietary treatment, while faecal score was ameliorated in T piglets after one week on trial (P< 0.05). Haptoglobin serum content was decreased in treated pigs (P<0.01). Dietary treatment did not affect serum Fe content, while vitamin B12 level was higher in nucleotide-fed animals (P< 0.05). At slaughtering IL6, IL10, TNF, TLR2 and TLR4 gene expression were decreased in nucleotide-fed pigs (P< 0.01). By these findings, dietary nucleotides supplementation in post-weaning piglets can positively affect gut health status, ameliorating inflammatory response and digestibility of nutrients in microbial stress conditions. Second study was carried out with the aim to investigate the antimicrobial potential of a polyphenol-rich olive extract in vitro and its effects on growth performance, caecum microbial population, slaughtering performance and meat quality. In vitro antimicrobial trials were performed on test cultures (E. coli ATCC 25922, L. monocytogenes ATCC 7644, S. Enteritidis ATCC 12592 and S. aureus ATCC 6833); the growth was assessed every 12 h for 48 h as optical density of broth cultures added with different concentrations of the product (0.1/0.5/1/5%) incubated at 20°C; an evident inhibition was observed with the increasing of the product concentration and a total inhibition was observed with the highest one. Considering these results, an in vivo trial was performed. A total of 720 female ROSS308 broiler chicks with day-old were allocated into 4 treatments with different dietary treatments (basal diet supplemented without (CTR) or with vitamin E (T1, 200 I.U. /kg for each dietary phase) or with Polyphenols olive extract (T2, 1g/kg and T3, 5 g/kg respectively in each dietary phase). Each group consisted of 9 pens with 20 birds per pen. Growth performances were determined at days 0, 10, 20 and 35. At day 35, two birds of each pen were chosen on average pen weight basis and slaughtered: from one was collected the cecum for microbial analyses and for the determination of the dressing and breast muscle percentages and the other one was collected for the measurements of pH, TBARS content and color at day 0 and after 9 days, mimicking the commercial preservation after slaughter. Supplementation with polyphenols olive extract showed only a tendency in Feed Conversion Ratio, in particular in the three phase of administration and in overall performance period (0-35 d) of animals (respectively P=0.09 and P=0.07) and T2 result lower compared to control group. No other evidence was observed in growth performances measured included carcass measures on dressing and breast muscle percentage. In addition, no differences were observed in cecum microbial population and gut health indexes. TBARS showed a statistical tendency (P=0.075), T1 resulted with lower oxidation if compared to all other groups (P<0.05); pH value and color of breast, skin and thigh, expressed with L*, a* and b*, did not explain any statistically difference. In conclusion in addition to promising in vitro data obtained, it would be interesting to evaluate the potential of the administration of this type of polyphenols in animals subjected to the stress of intensive livestock production, where more interesting results due to potential expressed with antimicrobial and antioxidant activity could be obtained. Third and fourth trials were carried out to evaluate different effects of a novel synthetic emulsifier. First step, the third trial, consist in two experiments conducted to evaluate the effects of a novel synthetic emulsifier product (AVI-MUL TOP) on the growth performance of chickens for fattening and weaned piglets. The emulsifier product consists of 50% vegetal bi-distillated oleic acid emulsified with 50% glyceryl polyethyleneglycol ricinoleate. In Exp. 1, four hundred and eighty 1-d-old female Cobb500 chickens for fattening were assigned to two treatments: 1) a control diet (CTR); and 2) the control diet + the emulsifier (AMT, 1 g/kg from day 0 to day 10, 0.75 g/kg from day 10 to day 20 and 0.5 g/kg from day 20 to day 34). AMT supplementation increased body weight on days 20 and 34 (P < 0.01). Dietary AMT increased the average daily gain (ADG) and average daily feed intake (ADFI) from day 10 to day 20, from day 20 to day 34 and from day 0 to 34 (P < 0.01). A reduced feed conversion ratio was observed in the AMT group from day 10 to day 20 (P < 0.01). In Exp. 2, ninety-six Stambo HBI × Dalland piglets were weaned at 24 days and assigned to 2 treatments (the basal diet without the product (CTR) or with 2 g/kg emulsifier from day 0 to day 14 and 1.5 g/kg from day 14 to day 42 (AMT)). There was an increase in the ADFI associated with AMT supplementation from day 14 to day 42 (P = 0.04). These results indicated that supplementation with the synthetic emulsifier may significantly improve the growth performance of chickens for fattening and numerically improve that of weaned piglets. Second step consist in to investigate the influence of a novel synthetic emulsifier product (AVI-MUL TOP) on growth performance, plasma lipid profile and hepatic expression of related genes in female and male broiler chicks. A total of 1200 ROSS308 broiler chicks with day-old were allocated into 4 treatments with a 2 × 2 factorial design comparing sex (female or male) and different dietary treatments (basal diet supplemented without (CTR) or with the emulsifier (AMT, 1 g/kg from d 0 to 12, 0.75 g/kg from d 12 to 22 and 0.5 g/kg from d 22 to 44, respectively)). Each group consisted of 15 pens, 20 birds per pen. Growth performance was determined at days 0, 12, 22 and 44 (37 for females). At day 44 (37 for females), one bird of each pen was chosen and slaughtered to collect blood and livers samples and determine the dressing and breast muscle percentages. Males had higher BW than female chicks on days 0 (P = 0.014), 12 (P < 0.01) and 22 (P < 0.01). Compared to females, male chicks had higher ADG and ADFI from day 0 to 12 and from day 12 to 22 (P < 0.01), and lower FCR from day 12 to 22 (P < 0.01). AMT supplementation increased the BW compared to the CTR group on days 12 (P = 0.02), and AMT chicks had higher ADG compared to the CTR birds from day 0 to 12 (P = 0.02). AMT male chicks had lower FCR compared to the CTR males from day 22 to 44 and day 0 to 44 (P = 0.047 and 0.02). However, there was no diet effect on growth performance of female chicks during the trial. AMT supplementation increased dressing percentage compared to the CTR group (P = 0.02). In addition, dietary AMT increased cholesterol, HDL and LDL contents compared to the CTR group (P < 0.01; P = 0.02; P < 0.01). In conclusion, supplementation of AMT may have beneficial effect on growth performance and plasma lipid profile of broiler chicks.

Three experiments were conducted to study the sensitivity of the pH-stat (in vitro) method in the prediction of true digestibility (TD), as measured by amount of base added, of plant proteins, either alone or in the presence of specific additives (nitrogen-free mixture, vitamin mixture and/or mineral mixture) as part of a complete diet of plant proteins that had been subjected to various levels and forms of heating. The in vitro TD values were then compared with TD values obtained in. vivo (Wistar rats). In experiment 1, the effect of temperature (dry-heating at 80, 100, 120, 150, 180 and 240° C or autoclaving at 121° C) and time (30, 60, 120 and 240 minutes) of heat application on in vitro base consumption (BC) was measured in 3 grains (wheat, barley and sorghum) and whole defatted soybeans. The largest increase in BC measured by the pH-stat method was that of soybeans in response to 30 minutes of autoclaving. Dry heating had various effects on the BC by soybeans, depending upon temperature and time of application, but none of the treatments was as beneficial as autoclaving. Mild, dry-heating of grains at 80-120° C improved BC slightly. The improvement was most marked for wheat. Both dry-heating of grain at temperatures above 120° C and autoclaving reduced the BC significantly for all durations. In experiment 2, the effect of inclusion of non-protein dietary components (minerals, vitamins and a nitrogen-free mixture, singly and in combination) on in. vitro BC measured by the pH-stat method of wheat and fat-extracted soybeans (both proteins in the raw and autoclaved forms) was monitored. For the wheat treatments, the inclusion of a mineral mixture significantly (p<0.001>) increased digestibility. This effect was greatest with autoclaved wheat. It was concluded that, in general, the presence of minerals increased the rate of hydrolysis. With raw soybeans, the distinction between treatments was less well-defined. The treatments containing vitamin or nitrogen-free and mineral combination mixtures were digested to a significantly greater extent than the raw soybeans alone. With autoclaved soybeans, additives had no effect. This lack of response to additives may have been due to the rather large amount of base required by the autoclaved soybean protein alone. In experiment 3, a series of rat-feeding trials were conducted in conjunction with in. vitro digestions. Diets were fed to groups of Wistar rats to determine TD, Biological Value (BV), and Net Protein Utilization (NPU) in vivo. Although BV was measured it was not relevant for this work. Concurrently, the same diets were tested for in. vitro TD by the pH-stat method. Specific regression equations were developed for each protein-type tested, after it was determined that a much lower correlation coefficient was obtained when one general equation was utilized. The newly-developed equations followed the format y = a + bx, where y = TD (as a part of one), a = the y-intercept, b = slope of the function and x = ml 0.10N NaOH added during the 10-minute digestion. Regression equations, correlation coefficients (r) and standard errors for each regression (s) between in. vitro and in vivo true digestibility of proteins were as follows; Soybean, soybean (autoclaved), soybean/wheat combinations (n = 6) r = 0.93 TD = 0.7868 + 0.2175x s = 0.018 Sorghum (raw, autoclaved, 90° C, 120° C, 180° C dry-heated, steamed) (n = 6) r = 0.92 TD = 0.4575 + 1.8841x a = 0.058 Alfalfa pellets/hay in combination with either wheat or barley (n = 13) r = 0.91 TD = 0.3446 + 1.0356x s = 0.046Alfalfa hay and barley combinations (n = 5) r = 0.96 TD = 0.2360 + 1.3194x s = 0.048 Grains (19 barleys, 10 triticales, 6 sorghums, and 2 wheats) (n = 37) r = 0.74 TD = 0.7419 + 0.4759x s = 0.044 In general, it can be stated that the pH-stat method is a useful method for screening proteins for the effect of various treatments on digestibility. Damage due to abnormally severe processing conditions (i.e. heating) is readily detected by the pH-stat technique as indicated by a decrease in the amount of base consumed during enzymatic hydrolysis.
Land and Food Systems, Faculty of
Graduate

Rats, mice, pigs, quails, chickens, steers and even some insects are unable to grow properly and in some cases die when fed on diets containing raw kidney bean (Phaseolus vulgaris). Although this problem has been extensively studied the precise mechanism of the interference of dietary antinutritional factors with the growth and health of these animals or insects is still not completely understood. In the present work, the toxic effects of the purified kidney bean globulin lectins upon the general metabolism of the rats were studied. The results of the experiments indicated that both qualitatively and quantitatively most of the deleterious effects of raw kidney bean feeding to rats could be accounted for by the inclusion of the pure lectin into nutritionally adequate semi-synthetic diets based on high-quality proteins such as egg albumin. These effects included: (a) a drastic depletion of storage lipid and glycogen and loss of body protein. (The rate of the catabolism of lipids was considerably higher than that of any other body constituent.); (b) a large loss of skeletal muscle (indicated by the change of muscle mass and atrophy of gastrocnemius and plantaris muscles); (c) enlargement of the small intestine, liver and pancreas and involution of the thymus; (d) increased excretion of faecal and urinary nitrogen with a consequently poor nitrogen retention; (e) increased 3-hydroxybutyrate output, and (f) changes in blood concentrations of pancreatic hormones. The magnitude of most of these effects was dependent upon the dietary concentrations of kidney bean globulin lectins (PHA). Thus the extent of the depletion of body lipid and glycogen, loss of muscle, enlargement of the small intestine, liver and pancreas, the extent of the thymus atrophy as well as the increased faecal and urinary nitrogen and increased urinary 3-hydroxybutyrate outputs were shown to be directly correlated with the dietary PHA concentration. In contrast to the deleterious effects of fully active, native PHA, the aggregated lectin preparation (UPHA) did not cause any significant antinutritional effects. The overall results indicated that raw kidney bean is toxic mainly because of its lectin constituent and that local (gut) and systemic adverse reactions caused by PHA account for most of the deleterious effects of this potentially important source of dietary protein for animals and humans.

The use of lupin seed, although a rich source of proteins, has been limited by the presence of toxic alkaloids. Recently a sweet, non toxic variety (it Lupinus angustifolius L.) has been developed in Western Australia, and reported to be safe for human consumption. However growth depression and low net protein utilisation (NPU) values in weanling rats fed raw L. angustifolius seeds have been reported in the literature. Thus seeds were analysed, and experiments were carried out with rats to evaluate NPU values and growth. Results indicated that L. angustifolius contains a far less reactive lectin than kidney bean, but that food intake and growth were depressed, due in part to essential amino acids (EAA) deficiencies. Supplementation with EAA improved growth, nitrogen retention and protein utilisation. However, when compared with that of the net protein utilisation values from rats fed on lactalbumin, the raw lupin seed meal was still found to be inferior, even when supplemented with EAA. Seed meal was fractionated into six components by sequential extraction with cold water, McIlvaine's buffer at pH 7.0, and dialysis of the supernatant. Analyses were carried out on lupin seed meal and fractions for carbohydrates, amino acids, oligosaccharides, minerals, phytates and run on SDS/PAGE to ensure consistency in fractions pooled for nitrogen balance experiments. It was revealed that a protein fraction resembling the gamma-conglutin, the simplest of the three globulins from the seeds of L.angustifolius, was extracted in almost pure form. A series of experiments was carried out to study the biological effects of all six fractions in growing rats. Results showed that seed meal and its fractions are unique in causing deleterious effects on liver, kidneys, spleen, thymus, heart, adrenal, stomach, caecum and colon but had no effects on pancreas.

Native Glycoprotein II (Phaseolin, G-II), the major 7S storage protein from Phaseolus vulgaris seeds, var. 'Processor' is known to be resistant to in vitro proteolysis by most endopeptidases. On sequential treatments with pepsin and a mixture of trypsin and chymotrypsin, the sub-unit polypeptides of G-II were split midchain. The fragments produced however, retained reactivity with the antibody raised against native G-II quantitatively. When measured by rocket immunoelectrophoresis, the extent of in vitro degradation of G-II by these endopeptidases was negligible. This procedure was used for monitoring the in vivo or in vitro degradation of G-II by gut enzymes other than trypsin or chymotrypsin. Diets containing 10% of a highly purified G-II preparation, did not support growth of rats adequately. Faecal N outputs were elevated and the true N digestibility based on Kjeldhal estimation was only 37%. In contrast, the true GII-N digestibility, based on immunological estimations, was high. It is suggested that G-II and/or its limited breakdown fragments (by trypsin or chymotrypsin) are stimulants of endogenous N secretion in the small intestine. The higher extent of the degradation of G-II in the small intestine of rats in vivo than that obtained by pure endopeptidases in vitro suggested the presence in this tissue of other enzymes capable to act upon and modify the structure of G-II, prior to the action of trypsin and chymotrypsin. These other modifying proteolytic enzymes render the G-II molecule more negatively charged and more susceptible to the subsequent action of trypsin and chymotrypsin. It is suggested that protease content and the ratio of the concentration of the GII-modifying protease(s) to that of trypsin and chymotrypsin may vary appreciably along the small intestine. Accordingly, the dependence of the degradation of G-II in vivo on the competition between all the enzymes capable of attacking it during its passage through the gut may explain the variability of GII breakdown in vivo.

Retrograded starches are commonly found in foods due to the production and/or processing conditions they have received prior to consumption. These resistant starches escape digestion in the small intestine and are fermented in the colon by the microflora present, to produce gases and SCFA in varying amounts. These are utilised by the host animal as an energy source, with a low gut pH being maintained by the production of SCFA. The fermentation of carbohydrates within the colon is beneficial to the health of the gut, as the beneficial bacterial species such as Lactobacillus and Bifidobacterium spp. are maintained, and a low pH reduces the activity of potentially harmful species such as the coliforms. The production of toxic metabolites from the breakdown of proteins will be reduced if these resistant starches persist further along the colon as a carbohydrate source. This is particularly important in the distal region of the colon, where the carbohydrate source usually becomes limited. The fermentation of both native and retrograded starches from various botanical sources containing varying amounts of the major components amylose and amylopectin, was examined. In particular, the effects on bacterial fermentation of variations in the ratios of amylose and amylopectin in starch, and of treatments such as retrogradation and/or pancreatin digestion was examined.

Orientador: Luciano Hauschild
Resumo: Dois estudos foram conduzidos com objetivo de comparar a biodisponibilidade relativa de L-Met e DL-Met com base em ensaio de balanço de N e os efeitos promovidos por ambas as fontes na morfologia intestinal e no sistema antioxidante de suínos em fase inicial e final de creche. Em cada experimento foram utilizados 42 suínos machos castrados (Agroceres PIC, Rio Claro, SP, Brazil: CamboroughTM x AGPIC 337TM) com peso inicial de 10,7 ± 1,09 kg e 20,5 ± 1,55 kg, respectivamente para o experimento 1 e o experimento 2. Cada experimento foi dividido em dois períodos experimentais com 21 suínos. Cada período experimental correspondeu a um bloco. Três suínos foram distribuídos aleatoriamente em 7 dietas experimentais dentro de cada bloco, resultando em um total de 6 repetições por tratamento. As dietas basais (DB) foram formuladas com deficiência de 68% em metionina, porém adequadas para os demais aminoácidos. Três níveis graduados de DL-Met e L-Met (0,03, 0,06 e 0,09%) foram suplementados à dieta basal para criar as dietas 2-7 em ambos os estudos. No experimento 1, ambas as fontes de metionina reduziram linearmente o N excretado pela urina e aumentaram linearmente a retenção de N (% de absorvido) (P ≤ 0,03). A biodisponibilidade relativa estimada para L-Met em comparação a DL-Met foi de 106% (intervalo de confiança – IC de 95%: 39 a 173%) para retenção de N (% de absorvido) em uma base equi-molar. No experimento 2, a suplementação com ambas as fontes de Met diminuiu linearmente a excr... (Resumo completo, clicar acesso eletrônico abaixo)
Abstract: Two studies were conducted to compare the relative bioavailability of L-Met and DL-Met based on N balance assay and the effects promoted by both sources on intestinal morphology and antioxidant system of weaned and growing pigs. In each experiment were used 42 barrows (Agroceres PIC, Rio Claro, SP, Brazil: CamboroughTM x AGPIC 337TM) with initial body weight of 10.7 ± 1.09 kg and 20.5 ± 1.55 kg, respectively for Experiment 1 and Experiment 2. Each experiment was divided into two batches with 21 pigs. Each batch corresponded to a block. Three pigs were randomly assigned to 7 experimental diets within each block, resulting in a total of 6 replicates per treatment. Basal diets (BD) were formulated with 68% methionine deficiency, but adequate for the other amino acids. Three graded levels of DL-Met and L-Met (0.03, 0.06 and 0.09%) were supplemented to the basal diet to create diets 2-7 in both studies. In experiment 1, both sources of methionine linearly reduced N excreted in the urine and linearly increased N retention (% absorbed) (P ≤ 0.03). The estimated relative bioavailability for L-Met compared to DL-Met was 106% (95% CI - confidence interval: 39 to 173%) for N retention (% absorbed) on an equi-molar basis. In experiment 2, supplementation with both Met sources linearly decreased urinary N excretion and linearly increased total N retention, N retention (% ingested and% absorbed) (P ≤ 0.04). The estimated bioavailability of L-Met compared to DL-Met was 95% (95% CI: 13 to 17... (Complete abstract click electronic access below)
Mestre

Lo scopo del presente lavoro è stato quello di esaminare il potenziale di idrolisi e degradabilità dell’amido dei cereali e co-prodotti e di valutare gli aspetti collegati. L’approccio utilizzato comprende sia test in vitro che in vivo. In particolare: - Una serie d’indagini in vitro ha fornito dati sul potenziale di degradabilità enzimatica dell’amido dei cereali e co-prodotti considerando sia l’influenza della struttura dell’amido, del tipo di cereale, del rapporto amilosio:amilopectina, del processo termico, dell’insilamento, dello stadio di maturazione e delle pratiche agronomiche. - Una valutazione funzionale basata sul calcolo del potenziale di degradabilità enzimatica dell’amido tramite la stima dell’indice glicemico in vitro, combinata con un approccio matematico di modellizzazione dei dati ottenuti, è stata proposta per fornire un metodo efficace di screening dei materiali amidacei utilizzati comunamente nella formulazione per diete destinate ai suini. - Un esperimento in vitro è stato condotto per investigare la risposta glicemica post-prandiale in suini alimentati con diete che differivano nel potenziale di idrolisi enzimatica. Infine, considerando la crescente attenzione dei nutrizionisti sulla matrice proteica dei cereali (con particolare importanza data alle prolammine), i metodi comunemente utilizzati per le tecniche di estrazione delle prolammine sono stati confrontati e ri-investigati.
In the present work, it has been attempted to examine the variability in starch hydrolysis and digestion from cereal grains and co-products and to study aspects related, in order to give a better understand of the science behind the differences in grains/feeds starch digestion potential. The general approach was to use a combination of in vitro and in vivo techniques. In particular: - A series of in vitro investigations has provided data on the degradation potential of starch from cereal grains and co-products considering the influence of starch structure, cereal type, amylose-amylopectin ratio, heat processing, ensiling, stage of maturity and of agricultural practices. - A laboratory-based functional evaluation of starch value of cereal grains based on a predicted glycemic index approach, combined with a mathematical first-order exponential model, has been proposed in order to allow an efficient screening of starchy-materials entering in the pig diet formulation. - An in vivo experiment has been undertaken to investigate the postprandial plasma glucose response in pigs fed diets containing starch with a wide range in in vitro digestion patterns. Lastly, taking into account the increasing attention of swine nutritionists on prolamin proteins, the most commonly used prolamin extraction procedures were compared and reinvestigated, in order to get useful information for routine lab analysis.

Lo scopo del presente lavoro è stato quello di esaminare il potenziale di idrolisi e degradabilità dell’amido dei cereali e co-prodotti e di valutare gli aspetti collegati. L’approccio utilizzato comprende sia test in vitro che in vivo. In particolare: - Una serie d’indagini in vitro ha fornito dati sul potenziale di degradabilità enzimatica dell’amido dei cereali e co-prodotti considerando sia l’influenza della struttura dell’amido, del tipo di cereale, del rapporto amilosio:amilopectina, del processo termico, dell’insilamento, dello stadio di maturazione e delle pratiche agronomiche. - Una valutazione funzionale basata sul calcolo del potenziale di degradabilità enzimatica dell’amido tramite la stima dell’indice glicemico in vitro, combinata con un approccio matematico di modellizzazione dei dati ottenuti, è stata proposta per fornire un metodo efficace di screening dei materiali amidacei utilizzati comunamente nella formulazione per diete destinate ai suini. - Un esperimento in vitro è stato condotto per investigare la risposta glicemica post-prandiale in suini alimentati con diete che differivano nel potenziale di idrolisi enzimatica. Infine, considerando la crescente attenzione dei nutrizionisti sulla matrice proteica dei cereali (con particolare importanza data alle prolammine), i metodi comunemente utilizzati per le tecniche di estrazione delle prolammine sono stati confrontati e ri-investigati.
In the present work, it has been attempted to examine the variability in starch hydrolysis and digestion from cereal grains and co-products and to study aspects related, in order to give a better understand of the science behind the differences in grains/feeds starch digestion potential. The general approach was to use a combination of in vitro and in vivo techniques. In particular: - A series of in vitro investigations has provided data on the degradation potential of starch from cereal grains and co-products considering the influence of starch structure, cereal type, amylose-amylopectin ratio, heat processing, ensiling, stage of maturity and of agricultural practices. - A laboratory-based functional evaluation of starch value of cereal grains based on a predicted glycemic index approach, combined with a mathematical first-order exponential model, has been proposed in order to allow an efficient screening of starchy-materials entering in the pig diet formulation. - An in vivo experiment has been undertaken to investigate the postprandial plasma glucose response in pigs fed diets containing starch with a wide range in in vitro digestion patterns. Lastly, taking into account the increasing attention of swine nutritionists on prolamin proteins, the most commonly used prolamin extraction procedures were compared and reinvestigated, in order to get useful information for routine lab analysis.

The objective of the experiments conducted for this dissertation was to determine the standardized ileal digestibility (SID) of amino acids (AA) in a variety of feed ingredients for broiler chickens and pigs. The effects of casein in experimental diets on the SID of AA in corn distillers’ dried grains with solubles (DDGS) fed to pigs were evaluated. The SID of AA in feed ingredients, which include full-fat soybean (FFSB), two soybean meals (SBM), peanut flour (PNF), full-fat canola seeds (FFCS), canola meal (CM), canola expellers (CE), hydrolyzed feather meal (HFM), flash dried poultry protein (FDPP), poultry meal (PM), and meat and bone meal (MBM), were compared in broiler chickens and pigs. One of the studies determined the ileal digestibility of AA in casein by regression analysis and investigated the effects of 60 g/kg casein in experimental diets on the SID of AA in DDGS. The ileal digestibility of AA in casein were close to 100%, ranging from 95.5% (SE = 9.10) for Cys to 103.1% (SE = 4.40) for Arg. In addition, the SID of Lys and Phe in DDGS determined by pigs fed the diet containing DDGS and casein were greater (P < 0.05) than the values determined by pigs fed the diet containing DDGS without casein. Based on the results of this experiment, two additional experiments were conducted to determine the effects of graded concentrations of casein from 55 to 165 g/kg in experimental diets on the SID of AA in DDGS and to determine the effects of dietary DDGS concentrations (i.e., 155.6 or 466.8 g/kg) and addition of casein in experimental diets on the SID of AA in DDGS. The SID of indispensable AA, except for Arg and Lys, linearly decreased (P < 0.05) as the concentration of casein in experimental diets increased. Moreover, pigs fed the diets containing 155.6 g/kg DDGS had less (P < 0.05) SID of indispensable AA, except for Trp, in DDGS than those fed the diets containing 466.8 g/kg DDGS regardless of the addition of casein in experimental diets. Therefore, it may be concluded that the addition of casein improves the SID of AA in DDGS, but reduced DDGS concentration in experimental diets decreases the SID of AA in DDGS. In one pair of experiments conducted to compare the SID of AA in FFSB, SBM containing 430 g/kg crude protein, SBM containing 470 g/kg crude protein, and PNF between broiler chickens and pigs, the SID of AA, except for Trp, Ala, and Glu, in test ingredients for pigs were greater (P < 0.05) than the values for broiler chickens. In addition, in both broiler chickens and pigs, the SID of Ile, Leu, and Val in FFSB were less (P < 0.05) than in the other test ingredients. In another pair of experiments conducted to compare the SID of AA in FFCS, CM, and CE between broiler chickens and pigs, interactions (P < 0.05) between experimental diets and species were observed in the SID of AA, except for Lys, Gly, Pro, and Ser. The SID of AA in FFCS for broiler chickens were greater (P < 0.05) than pigs; however, there was no difference in the SID of AA in CM or CE between broiler chickens and pigs. The objective of a third pair of experiments was to compare the SID of AA in HFM, FDPP, PM, and MBM fed to broiler chickens and pigs. There were interactions (P < 0.05) between experimental diets and species in the SID of His, Thr, Trp, and Val. In broiler chickens, the SID of His, Thr, and Trp in FDPP and PM were greater (P < 0.05) than in HFM but were less (P < 0.05) than MBM; however, difference in SID of His, Thr, and Trp among FDPP, PM, and MBM was not observed in pigs. Based on the results of three pairs of studies, it was revealed that differences in SID of AA in common feed ingredients for both broiler chickens and pigs were affected by species. Therefore, it may be concluded that the effects of feed ingredient-specific factors on the SID of AA are different between broiler chickens and pigs.

The purpose of this reseach was to explore the potential for improved utilization of canola meal by monogastric animals. In study one, 26 yellow-seeded and 7 brown-seeded Brassica genotypes were evaluated for differences in chemical composition and dietary fibre profiles. On average, in comparison to brown-seeded, yellow-seeded genotypes contained more sucrose (8.7% vs 7.5%) and protein (44.5% vs 42.7%) and less dietary fibre (28% vs 33%). Dietary fibre was negatively correlated (r=-0.71) with protein content and its reduction in yellow-seeded samples was attributed to lower contents of lignin and polyphenols, cell wall protein and minerals associated with the fibre fraction. In a second study, selected Brassica genotypes were analyzed for digestible protein, soluble fibre, content of soluble phenolics and extract viscosity. Despite only minor differences in soluble fibre, soluble phenolics and extract viscosity, B. rapa and B. napus species had relatively high digestible protein content in comparison to B. juncea and B. carinata species. The measurements of digestible protein and dietary fibre as well as soluble phenolics and extract viscosity were poorly correlated. Based on chemical composition and digestible protein content, four Brassica cultivars were selected for use in a third study and the seeds were processed under optimal moist heat treatment conditions (108 + 1oC for 20 min). The samples included yellow-seeded B. rapa (cv. Parkland), B. rupus (cv. Y1016) and B. juncea (J4316) and brown-seeded B. rapus (cv. Excel). With the exception of B. rapa, all samples had higher than commercial meals protein content with the yellow-seeded B. napus canola showing the highest true metabolizable energy value. The overall performance of broiler chickens fed the Brassica seed meals was similar to that of the commercial meal from yellow-seeded canola (control) except for B. juncea which had a relatively high content of undesirable aliphatic glucosinolates. Of the diets with comparable growth performance, birds fed the yellow-seeded B. napus canola showed the highest feed efficiency value. In a forth study an attempt was made to improve the utilization of canola meal by supplementation of broiler chicken diets with exogenous enzymes. A positive and synergistic effect was noted when a combination of protease, carbohydrase and phytase enzymes were supplemented to canola meal-based diets deficient in available phosphorus.

In the pig and poultry production industries, energy forms the largest and the greatest cost pressure when a diet is formulated. In Australia, cereal grains such as barley, sorghum, and wheat are the main dietary energy sources, comprising more than 60 % of the diet in many cases. Traditionally, during diet formulation, the energy value of a grain has been represented by a single figure for that particular grain type. However, several studies have indicated that the energy availability from different grains fed to pigs and poultry varies significantly even within one grain cultivar. Given these findings, the use of a single value to represent the energy of each grain type during diet formulation, can lead to inefficient utilisation of dietary resources by animals, and thus decreased animal performance and consequently, a decrease in profit for the pig and poultry production industries. Thus, there is an opportunity to develop a rapid and reproducible in vitro assay to accurately assess the available energy values and nutritional quality of each grain type. In order to develop such an assay, further understanding of factors that affect the available energy values of grains need to be explored. Starch, which is hydrolysed into glucose by animals, is the most abundant energy component in cereal grains, and there is evidence suggesting that variations in digestible or metabolisable energy values may be related to the extent of starch digestibility. For example in poultry, variations in the in vitro digestibility of starch between several wheat cultivars have been shown to correlate with their in vivo available metabolisable energy values. However, it is not known to what extent starch digestibility varies between cultivars of other grain types such as barley and sorghum. There is an increasing body of evidence suggesting that differences in the physical and chemical properties of cereal grains may play an important role in influencing starch digestibility and, consequently, animal performance. Thus, the general hypothesis of this study was that starch digestibility varies between barley, sorghum and wheat, and between cultivars within grain types and this is related to specific chemical and physical characteristics of the grains. To examine this, the following issues were investigated using 18 barley, 15 sorghum and 10 wheat cultivars : 1 ) an in vitro glucose release index ( GRI ) assay was developed to assess starch digestibility within and between the cereal grain types and, 2 ) the GRI was correlated to both starch - related ( e.g., starch content, starch granule size, the amylose to amylopectin ratio, starch gelatinisation properties ) and non - starch - related ( e.g., non - starch polysaccharide composition, kernel hardness, the presence of protein matrix and milling quality ) physical / chemical characteristics within and between the cereal grains. Results revealed significant variations in the GRI both between grains and within a given grain type. The GRI values ranged between 27 - 45 %, 25 - 54 % and 32 - 53 % in barley, sorghum and wheat respectively. Correlation analysis revealed that the GRI in barley, sorghum and wheat was influenced by the physical and chemical characteristics of starch - and non - starch - related grain properties, although the type of characteristic influencing GRI was specific to the grain type. In barley, the ratio of amylose to amylopectin, starch gelatinisation and kernel hardness influenced the GRI. In sorghum, the GRI was influenced by the ratio of amylose to amylopectin, the presence of a protein matrix surrounding starch granules and kernel hardness. Finally in wheat, the presence of protein matrix and milling quality influenced the GRI. It was also shown that the extract viscosity of grains within barley and wheat, but not sorghum, varied significantly. In conclusion, the results from this study indicate that ; 1 ) the GRI assay may be used to identify some factors that affect in vivo starch digestibility within and between barley, sorghum and wheat, 2 ) starch digestibility ( as assessed by the GRI ) may be influenced by some physical and chemical characteristics of cereal grains, and that these characteristics are specific to the type of grain The physical and chemical characteristics that may influence starch digestion will be discussed in relation to their potential physiological effects on energy digestion, and utilisation in animals. The information generated will provide a basis for future studies that will ultimately assist in the design of in vitro assays to predict energy availability from barley, sorghum and wheat grains fed to pigs and poultry, and contribute to the more efficient use of grains in monogastric production systems.
Thesis (Ph.D.)--Department of Animal Science, 2002.

In the pig and poultry production industries, energy forms the largest and the greatest cost pressure when a diet is formulated. In Australia, cereal grains such as barley, sorghum, and wheat are the main dietary energy sources, comprising more than 60 % of the diet in many cases. Traditionally, during diet formulation, the energy value of a grain has been represented by a single figure for that particular grain type. However, several studies have indicated that the energy availability from different grains fed to pigs and poultry varies significantly even within one grain cultivar. Given these findings, the use of a single value to represent the energy of each grain type during diet formulation, can lead to inefficient utilisation of dietary resources by animals, and thus decreased animal performance and consequently, a decrease in profit for the pig and poultry production industries. Thus, there is an opportunity to develop a rapid and reproducible in vitro assay to accurately assess the available energy values and nutritional quality of each grain type. In order to develop such an assay, further understanding of factors that affect the available energy values of grains need to be explored. Starch, which is hydrolysed into glucose by animals, is the most abundant energy component in cereal grains, and there is evidence suggesting that variations in digestible or metabolisable energy values may be related to the extent of starch digestibility. For example in poultry, variations in the in vitro digestibility of starch between several wheat cultivars have been shown to correlate with their in vivo available metabolisable energy values. However, it is not known to what extent starch digestibility varies between cultivars of other grain types such as barley and sorghum. There is an increasing body of evidence suggesting that differences in the physical and chemical properties of cereal grains may play an important role in influencing starch digestibility and, consequently, animal performance. Thus, the general hypothesis of this study was that starch digestibility varies between barley, sorghum and wheat, and between cultivars within grain types and this is related to specific chemical and physical characteristics of the grains. To examine this, the following issues were investigated using 18 barley, 15 sorghum and 10 wheat cultivars : 1 ) an in vitro glucose release index ( GRI ) assay was developed to assess starch digestibility within and between the cereal grain types and, 2 ) the GRI was correlated to both starch - related ( e.g., starch content, starch granule size, the amylose to amylopectin ratio, starch gelatinisation properties ) and non - starch - related ( e.g., non - starch polysaccharide composition, kernel hardness, the presence of protein matrix and milling quality ) physical / chemical characteristics within and between the cereal grains. Results revealed significant variations in the GRI both between grains and within a given grain type. The GRI values ranged between 27 - 45 %, 25 - 54 % and 32 - 53 % in barley, sorghum and wheat respectively. Correlation analysis revealed that the GRI in barley, sorghum and wheat was influenced by the physical and chemical characteristics of starch - and non - starch - related grain properties, although the type of characteristic influencing GRI was specific to the grain type. In barley, the ratio of amylose to amylopectin, starch gelatinisation and kernel hardness influenced the GRI. In sorghum, the GRI was influenced by the ratio of amylose to amylopectin, the presence of a protein matrix surrounding starch granules and kernel hardness. Finally in wheat, the presence of protein matrix and milling quality influenced the GRI. It was also shown that the extract viscosity of grains within barley and wheat, but not sorghum, varied significantly. In conclusion, the results from this study indicate that ; 1 ) the GRI assay may be used to identify some factors that affect in vivo starch digestibility within and between barley, sorghum and wheat, 2 ) starch digestibility ( as assessed by the GRI ) may be influenced by some physical and chemical characteristics of cereal grains, and that these characteristics are specific to the type of grain The physical and chemical characteristics that may influence starch digestion will be discussed in relation to their potential physiological effects on energy digestion, and utilisation in animals. The information generated will provide a basis for future studies that will ultimately assist in the design of in vitro assays to predict energy availability from barley, sorghum and wheat grains fed to pigs and poultry, and contribute to the more efficient use of grains in monogastric production systems.
Thesis (Ph.D.)--Department of Animal Science, 2002.