Effects of alfalfa, wheat bran or beet pulp, with or without sunflower oil, on caecal fermentation and on digestibility in the rabbit

Performance and nutrigenomics modulations in response to the inclusion of biologically treated date-palm mulch and enzyme mixture in the diets of growing rabbits

This study was conducted to evaluate the effects of Allzyme addition on biologically-treated date-palm mulch (DPM) based diets for growing rabbits. DPM was treated by Trichoderma viride, Trichoderma reesi 230, Plorotus oysterous, and Phanaerochyte chrysosporium. Eighty rabbits were assigned to four groups: a control group, tDPM (10% tDPM inclusion of total diet), Allzyme (Allzyme supplementation), and tDPM + Allzyme (tDPM and Allzyme supplementation). The biological treatment resulted in a significant increase in crude protein and reductions in crude fiber. There was an interaction between tDPM and Allzyme at 9- and 10-week BW. The negative effects of tDPM on BW started at 8-week of age. The tDPM had unfavorable effects on slaughter and meat quality traits. The tDPM-by-Allzyme interaction affected total protein and globulin concentrations. However, blood glucose concentration was influenced by both tDPM and Allzyme. A significant tDPM effect was detected on the expression of INSR, GHSR, and IGF1 genes. However, the Allzyme effect was significant for PPARg and FASN genes. In conclusion, feeding tDPM negatively impacted rabbit's performance, however, Allzyme supplementation alleviated some of those effects. Accordingly, tDPM is recommended to be included in the diets of growing rabbits along with Allzyme supplementation.

Effect of Diet Supplementation with Oat Hay and Whole Carrot on Rabbit Growth and Productive Efficiency

Is it possible to reduce feeding costs in rabbit meat production without compromising rabbit health and productive yield? The study tested four feeding strategies: Control group (CC) fed exclusively with concentrate feed; group CT supplemented with whole carrot; group OH supplemented with oat hay; and Group CO supplemented with oat hay and whole carrot. Each feeding strategy was tested in 20 rabbits, randomly allocated in five cages with four rabbits each. The average daily weight gain (ADG), feed conversion ratio (FCR), and the amount of concentrated feed consumed daily were estimated in all experimental groups. Group CC displayed the best ADG (37.1 g/rabbit/day), carrot had no significant influence on ADG (34.2 g/rabbit/day), but oat hay had a negative impact (p < 0.05), either used alone or in combination with carrot (33.0 and 32.6 g/rabbit/day, respectively). Supplementation with carrot, oat hay, or both increased the FCR (p < 0.001). Nevertheless, there were no significant differences in final live weight or carcass weight between the rabbits in the different experimental groups. In conclusion, supplementation with oat hay, carrot, or both can be a valid approach to reducing production costs by decreasing concentrate feed without affecting rabbit's health and meat yield. The combined supplementation with oat hay and carrot proved to be the best option in reducing the amount of concentrate feed ingested by rabbits (less than 1107 g/animal), but at current market values, supplementation exclusively with oat hay was the less expensive feeding strategy (less 14% than fed exclusively with concentrate feeding).

Effect of Dietary Level of Beet Pulp, with or without Molasses, on Health Status, Growth Performance, and Carcass and Digestive Tract Traits of Rabbits

To evaluate the effect of dietary level of beet pulp, with or without molasses, on growth performance, a total of 470 28-day-old rabbits were used (614 ± 6 g). Animals were randomly allocated into five dietary treatment groups: Control, without beet pulp; BP20, and BP40 with 20 and 40% of beet pulp without molasses, respectively; and BPM20 and BPM40, with 20 and 40% of beet pulp with molasses, respectively. Daily feed intake (DFI) and average daily gain (ADG) were controlled at 28, 49, and 59 days of age. Carcass and digestive tract traits were also determined at 59 days of age. Mortality and morbidity were controlled daily. Mortality during the growing period was higher in BPM than in BP groups (+9.2%; p < 0.05). The higher the inclusion of beet pulp, the lower the DFI and ADG of animals (5.5 and 4.6% for every 20% inclusion, respectively; p < 0.001), as well as the dressing out percentage, the liver proportion, and the dissectible fat percentage of their carcasses. However, the best feed efficiency during the last 10 days was obtained with the BPM40 group. The higher the inclusion of beet pulp, the higher the weight of the empty gastrointestinal tract and cecum (+2.4 and +3.0 percentage points for every 20% inclusion, respectively; p < 0.001). In fact, a higher inclusion of beet pulp decreased the pH and dry matter and decreased the total volatile fatty acids content of cecum richer in acetic acid but poorer in propionic, isobutiric, isovaleric, and valeric acids. Stomach weight was lower, and the capric acid content in the cecum was higher in the BPM than in the BP group. The inclusion of beet pulp in the feed reduced the growth performance and carcass yield of growing rabbits, and an even higher incidence of digestive disorders was observed when beet pulp included molasses.

Production of Preserved Forage for Horses under Water Scarcity Conditions: A Case Study

The Mediterranean region is one of the areas most affected by climate change, which influences the production of forages. This has led producers to change from one to several forage cuttings, aiming to maintain crop productivity in increasingly water-scarce conditions. This study aimed to evaluate the nutrient content and productivity of forage produced for horses when subjected to variable water availability conditions at a Lusitano stud farm located in the central region of Portugal. The soil water content was evaluated throughout the growing season, using the gravimetric method, with soil samples collected every 15 days. Forage samples were collected from three grass cuttings (two for haylage and one for hay production), harvested from the same sward during the 2018/2019 growing season. The nutrient content of the forage samples was determined by chemical analysis. The global productivity throughout the crop-growing season was 8.3 t DM·ha−1, with the second harvest presenting the highest productivity (3.42 t DM·ha−1), corresponding to an adequate water supply, whereas the last cut, produced under water deficit conditions, presented the lowest productivity (2.1 t DM·ha−1). The estimated nutritive value by chemical composition analysis for both haylage and hay fell within the range reported in the literature for preserved forages for horses.

Effect of Type and Dietary Fat Content on Rabbit Growing Performance and Nutrient Retention from 34 to 63 Days Old

The study was carried out on individually and collectively housed growing rabbits from 34 to 63 days of age. Two experiments were conducted using three fat sources: Soybean oil (SBO), Soya Lecithin Oil (SLO), and Lard (L; Exp. 1), and SBO, Fish Oil (FO), and Palm kernel Oil (PKO; Exp. 2), added at two inclusion levels (1.5 and 4.0%). In both trials, 180 rabbits were housed in individual cages and additional 600 rabbits in collective cages from day 34 to 63. Animals fed with 4% dietary fat showed lower Daily Feed Intake (DFI) and Feed Conversion Ratio (FCR) than those fed with 1.5%, except in the individually housed animals in Exp. 1. In the collective housed group in Exp. 1, DFI was a 4.8% higher in animals fed with diets containing lard than those fed with SBO (p = 0.036). Lard inclusion also tended to reduce mortality (p = 0.067) by 60% and 25% compared with SBO and SLO diets, respectively. Mortality was the highest with the higher level of soya lecithin (14% vs. 1%, p < 0.01). A similar mortality rate was observed in the lowest level of SBO. In the grouped-housed animals in Exp. 2, a decrease of DFI (-12.4%), Bodyweight (BW) at 63 d (-4.8%), and Daily Weight Gain (DWG) (-7.8%) were observed with the inclusion of fish oil (p < 0.01) compared to other fat sources. Fish oil also tended to increase (p = 0.078) mortality (13.2%) compared with palm kernel oil (6.45%); similar results were found when animals were individually housed. The overall efficiency of N retention (NRE) increased with the highest level of fat in Exp. 1 (34.9 vs. 37.8%; p < 0.0001). It can be concluded that lard and palm kernel oil are alternative sources of fat due to the reduction of mortality. The inclusion of fish oil impaired animal productivity and increased mortality. An increment of the dietary fat level improved FCR and overall protein retention efficiency.

Dietary Lipids Influence Bioaccessibility of Polyphenols from Black Carrots and Affect Microbial Diversity under Simulated Gastrointestinal Digestion

The bioaccessibility and activity of polyphenols is dependent on their structure and entrapment in the food matrix. While dietary lipids are known to transit into the colon, the impact of different lipids on the microbiome, and their interactions with dietary polyphenols are largely unknown. Here, we investigated the effect of dietary lipids on the bioaccessibility of polyphenols from purple/black carrots and adaptation of the gut microbiome in a simulated in vitro digestion-fermentation. Coconut oil, sunflower oil, and beef tallow were selected to represent common dietary sources of medium-chain fatty acids (MCFAs), long-chain polyunsaturated fatty acids (PUFAs), and long-chain polysaturated fatty acids (SFAs), respectively. All lipids promoted the bioaccessibility of both anthocyanins and phenolic acids during intestinal digestion with coconut oil exhibiting the greatest protection of anthocyanins. Similar trends were shown in antioxidant assays (2,2-Diphenyl-1-pricrylhydrazyl (DPPH), ferric reducing ability (FRAP), and total phenolic content (TPC)) with higher phytochemical bioactivities observed with the addition of dietary lipids. Most bioactive polyphenols were decomposed during colonic fermentation. Black carrot modulated diversity and composition of a simulated gut microbiome. Dramatic shifts in gut microbiome were caused by coconut oil. Inclusion of sunflower oil improved the production of butyrate, potentially due to the presence of PUFAs. The results show that the impact of polyphenols in the digestive tract should be considered in the context of other components of the diet, particularly lipids.

Influence of inoculum type (ileal, caecal and faecal) on the in vitro fermentation of different sources of carbohydrates in rabbits

<p>Two <em>in vitro</em> experiments were performed to analyse the fermentative potential of ileal content, caecal content, soft faeces and hard faeces from adult rabbits. Experiment 1 evaluated 3 doses (0.5, 1.0 and 2.0 g fresh digesta/g substrate dry matter [DM]) of ileal and caecal digesta as inoculum in 28 h-incubations. Two ileal and 2 caecal inocula were obtained, each by pooling the ileal or caecal digesta of 2 adult rabbits. Pectin from sugar beet pulp (SBP) and the insoluble residue obtained after a 2-step <em>in vitro</em> pre-digestion of SBP and wheat straw were used as substrates. The 0.5 dose produced the lowest (<em>P</em>&lt;0.05) amount of gas at 28 h, with no differences (<em>P</em>&gt;0.05) between the 1.0 and 2.0 doses (44.9, 51.6 and 53.8 mL/g substrate DM, respectively; values averaged across inocula and substrates). Experiment 2 evaluated two doses of ileal inoculum (1 and 1.5 g fresh digesta/g substrate DM) and compared ileal digesta, caecal digesta, soft faeces and hard faeces as inoculum for determining <em>in vitro</em> gas production (144-h incubations) of the 3 substrates used in Experiment 1 and wheat starch. Three inocula of each type were obtained, each by pooling either digesta or faeces from 3 rabbits. There were no differences (<em>P</em>&gt;0.05) between the 2 ileal doses tested in gas production parameters, and therefore the 1.0 dose was selected for further ileal fermentations. Starch and pectin showed similar (<em>P</em>&gt;0.05) values of gas production rate and maximal gas production rate when they were fermented with caecal digesta (0.038 vs. 0.043%/h, and 13.7 vs. 15.2 mL/h, respectively), soft (0.022 vs. 0.031%/h, and 9.97 vs. 9.33 mL/h) and hard faeces (0.031 vs. 0.038%/h, and 13.6 vs. 10.8 mL/h), and values were higher than those for SBP and wheat straw; in contrast, values for starch and pectin differed with the ileal inoculum (0.046 vs. 0.024%/h, and 18.4 vs. 6.60 mL/h). Both ileal and caecal gas production parameters were well correlated with those for hard and soft faeces inocula, respectively (r≥0.77; <em>P</em>≤0.040). The ileal inoculum showed a relevant fermentative potential, but lower than that of caecal digesta and soft and hard faeces for all substrates except wheat starch.</p>

Effect of level of soluble fiber and n-6/n-3 fatty acid ratio on performance of rabbit does and their litters

The aim of this work was to study whether the dietary supplementation with soluble fiber (SF) and the reduction of the n-6/n-3 fatty acid ratio or the combination of both influences the survival, body and milk composition, and reproductive performance of rabbit does during the first four parturitions. Four diets in a 2 × 2 factorial arrangement were used with two levels of SF (7.8 vs. 13.0, on dry matter [DM] basis; high soluble fiber [HSF] and low soluble fiber [LSF]) and two different n-6/n-3 fatty acid ratios (13.4/1 vs. 3.5/1). Nulliparous does (24/diet) were inseminated 11 d after parturition. Body chemical composition and energy content of rabbit does and their performance, litter growth, and milk production were measured between birth and weaning (25 d) along four parturitions, and milk composition and fecal digestibility were also recorded. The proportion of total removed does decreased in HSF respect to LSF groups (22.9 vs. 50.0%; P = 0.005), and it tended to decrease in LSF groups when the n-6/n-3 ratio increased and in HSF groups when the n-6/n-3 ratio decreased (P = 0.059). The increase of the level of SF reduced the digestible crude protein (CP)/digestible energy ratio (by 4%; P < 0.001) and improved the digestibility of all fibrous fractions (P < 0.001). The reduction of the n-6/n-3 ratio reduced the total dietary fiber digestibility in rabbit does fed LSF diets, but it had no effect in those fed HSF diets (P = 0.043). Treatments had no effect on average daily feed intake among parturitions (P = 0.16), but the digestible CP intake among parturitions was lower in HSF than in LSF groups (P = 0.003). Treatments had no effect on the total number of kits born, litter or average kit weight at birth, or litter size at weaning, fertility, feed efficiency, total milk production, and body chemical composition and energy content of rabbit does (P ≥ 0.29). The average weight of kits at weaning of LSF_Hn-6/n-3 and HSF_Ln-6/n-3 groups decreased by 6% compared with those from the other two groups (P = 0.030). The reduction of the dietary n-6/n-3 ratio increased the milk fat content by 12% with no effect on protein and DM content (P = 0.031). The proportion of milk odd fatty acids and saturated fatty acid increased in rabbit does fed the HSF diets compared with those fed LSF diets (P ≤ 0.037) with no effect of the n-6/n-3 fatty acid ratio. In conclusion, SF reduced the replacement rate of rabbit does with no effect of the n-6/n-3 ratio, while both dietary factors modified milk composition and fatty acid profile with minor influence on litter productivity.

Diet simplification selects for high gut microbial diversity and strong fermenting ability in high-altitude pikas

The gut microbiota in mammals plays a key role in host metabolism and adaptation. However, relatively little is known regarding to how the animals adapts to extreme environments through regulating gut microbial diversity and function. Here, we investigated the diet, gut microbiota, short-chain fatty acid (SCFA) profiles, and cellulolytic activity from two common pika (Ochotona spp.) species in China, including Plateau pika (Ochotona curzoniae) from the Qinghai-Tibet Plateau and Daurian pika (Ochotona daurica) from the Inner Mongolia Grassland. Despite a partial diet overlap, Plateau pikas harbored lower diet diversity than Daurian pikas. Some bacteria (e.g., Prevotella and Ruminococcus) associated with fiber degradation were enriched in Plateau pikas. They harbored higher gut microbial diversity, total SCFA concentration, and cellulolytic activity than Daurian pikas. Interestingly, cellulolytic activity was positively correlated with the gut microbial diversity and SCFAs. Gut microbial communities and SCFA profiles were segregated structurally between host species. PICRUSt metagenome predictions demonstrated that microbial genes involved in carbohydrate metabolism and energy metabolism were overrepresented in the gut microbiota of Plateau pikas. Our results demonstrate that Plateau pikas harbor a stronger fermenting ability for the plant-based diet than Daurian pikas via gut microbial fermentation. The enhanced ability for utilization of plant-based diets in Plateau pikas may be partly a kind of microbiota adaptation for more energy requirements in cold and hypoxic high-altitude environments.

In vitro caecal fermentation of carbohydrate-rich feedstuffs in rabbits as affected by substrate pre-digestion and donors' diet

The influence of substrate pre-digestion and donors’ diet on <em>in vitro</em> caecal fermentation of different substrates in rabbits was investigated. Eight crossbreed rabbits were fed 2 experimental diets containing either low (LSF; 84.0 g/kg dry matter [DM]) or high soluble fibre (HSF; 130 g/kg DM) levels. <em>In vitro</em> incubations were conducted using batch cultures with soft faeces as inoculum and four fibrous or fibre-derived, low-starch and low-protein substrates: D-cellobiose (CEL), sugar beet pectin (PEC), sugar beet pulp (SBP) and wheat straw (WS). Substrates in half of the cultures were subjected to a 2-step pepsin/pancreatin in vitro digestion without filtration, and the whole residue (soluble, insoluble and added enzymes) was incubated at 39°C. Gas production was measured until 144 h, and volatile fatty acid (VFA) production at 24 h incubation was determined. Cultures without substrate (blanks) were included to correct gas production values for gas released from endogenous substrates and added enzymes. Pre-digestion had no influence on <em>in vitro</em> gas production kinetic of WS, and only reduced the time before gas production begins (lag time; by 31%; P=0.042) for SBP, but for both substrates the pre-digestion decreased the molar proportion of acetate (by 9%; P≤0.003) and increased those of propionate and butyrate (P≤0.014). For CEL, the pre-digestion increased the gas and total VFA production (by 30 and 114%), shortened the lag time (by 32%), and only when it was combined with LSF inoculum 38 percentage units of acetate were replaced by butyrate (P≤0.039). Treatments had a minor influence on in vitro fermentation traits of SBP pectin. The results showed that the pre-digestion process influenced the in vitro caecal fermentation in rabbits, but the effects were influenced by donors’ diet and the incubated substrate. Pre-digestion of substrate is recommended before conducting <em>in vitro</em> caecal fermentations. The level of soluble fibre in the donors’ diet also influenced the <em>in vitro</em> caecal fermentation, but its effect depended on the type of substrate.

Effect of substituting guinea grass with soybean hulls on production performance and digestion traits in fattening rabbits

The objective of this study was to evaluate the use of soybean hulls (SH) to substitute guinea grass (GG), traditionally used as fibre source in the diets of fattening rabbits on performance, coefficients of total tract apparent digestibility (CTTAD) of nutrients, gastrointestinal tract development and caecum fermentation. A total of 160 mixed sex Hyla commercial meat rabbits were allocated to 4 experimental groups (40 per treatment) differing in the SH level inclusion in the diet offered to rabbits from 40 to 90 d of age: 0, 50, 100 and 200 g/kg as-fed basis: SH0, SH50, SH100 and SH200 groups, respectively. Growth performance was recorded from 40 to 90 d of age, CTTAD of nutrients from 86 to 90 d of age, and gastrointestinal tract development, caecum fermentation and carcass traits were determined at 90 d of age. Average daily feed intake and the feed/gain ratio were lower in SH100 and SH200 groups than in SH0 group (P0.05). In conclusion, our results suggest that SH can substitute GG in the diets of fattening rabbits up to 200 g/kg in diet with no adverse effects on the growth performance, feed efficiency, carcass traits and meat quality.

In vitro study and comparison of caecal methanogenesis and fermentation pattern in the brown hare (Lepus europaeus) and domestic rabbit (Oryctolagus cuniculus)

The brown hare and the domestic rabbit are mid-sized herbivorous mammals and hindgut fermenters, though their digestive physiologies differ in some traits. The objective of this study was to estimate and compare the caecal microbial activity in hares and rabbits via an analysis of the following end-products of in vitro caecal fermentation: methane, total gas production, short chain fatty acids and ammonia concentration. Hare caecal methanogenesis occurred at a much lower level (0.25 mmol/kg for samples incubated without substrate and 0.22 mmol/kg for samples incubated with substrate) than that of the rabbit (15.49 and 11.73 mmol/kg, respectively) (P<0.001). The impact of the substrate’s presence on caecal methanogenesis was not significant, though its presence increased the total gas production during fermentation (P<0.001). Hare caecal microflora produced a lower short chain fatty acids concentration than did rabbit microorganisms (P<0.05). In unincubated hare samples, the short chain fatty acids concentration was 28.4 mmol/kg, whereas in unincubated rabbit samples, the short chain fatty acids concentration was 51.8 mmol/kg. The caecal fermentation pattern of the hare was characterised by higher propionate and isobutyrate molar proportions compared with those observed in rabbit caecum (P<0.01). No significant changes in the ammonia concentration in either rabbit or hare caecum were found. The results obtained indicate some differences in the activity of the microbial populations colonising the hare and rabbit caecum, particularly in regards to methanogenic Archaea.

Early modulation of the cecal microbial activity in the young rabbit with rapidly fermentable fiber: impact on health and growth

This study aimed at comparing various diets predicted to induce different stimulations of the cecal microbial activity of the young rabbit fed ad libitum from 16 to 70 d of age: i) a diet enriched with rapidly fermentable fiber expected to stimulate the cecal microbial activity (RFF group); ii) a control diet with a standard composition (C group); iii) and the same control diet with tiamulin and apramycin antibiotics, expected to inhibit the microbial activity (C+AB group). A total of 398 rabbits were used from 42 litters and weaned at 28 d of age. An in vivo digestibility trial was performed on 36 rabbits of 42 to 46 d of age housed in individual metabolic cages. The feed intake and growth rates were lower in the RFF group compared with the C+AB group (-15% in ADFI and -11% in ADG, P<0.001), with a lower weight of -183 g at 70 d (P<0.001). No significant difference was found on ADG and final BW between the RFF and the C groups, but the RFF diet allowed a better G:F ratio at postweaning (P<0.01). The digestion of soluble fiber (total dietary fiber minus NDF) was greater for the RFF group. The C+AB diet had a positive effect on the postweaning morbidity rate (P<0.05) but did not affect the mortality rate and the health risk index (morbidity and mortality). Conversely, the RFF diet appeared to reduce the mortality rate compared with the C+AB diet, especially before 41 d of age. Concerning the cecal microbial activity, a supply of RFF in the diet increased the cecal VFA concentrations (+28% vs. C+AB and +22% vs. C, P<0.001) and lowered the pH. The VFA pattern was affected at 45 and 60 d, with a dominance of acetate in the RFF group (+4% vs. C+AB and C groups, P<0.001) instead of butyrate in the C+AB and C groups (-3.6% and -5% vs. C+AB and C, respectively, P<0.001). Antibiotics addition (C+AB group) reduced the VFA concentration, but only after weaning (-25% at 45 d of age) without changing the fermentation pattern. In conclusion, early intake of RFF in young rabbits stimulated the cecal microbial activity, and reduced the voluntary feed intake, leading to a reduced G:F ratio.

Effect of dietary soybean oil addition on the odd-numbered and branched-chain fatty acids in rabbit meat

The effect of dietary soybean oil (SO) inclusion (20g/kg) on the odd-numbered (ONFA) and branched-chain (BCFA) fatty acids (FA) of two muscles, differing in fatness (Longissimus lumborum and Biceps femoris), was studied in 24 New ZealandxCalifornian rabbits. The increased muscle fatness in Biceps femoris (P<0.001) was related to higher saturated (P<0.01) and monounsaturated (P<0.01) fatty acids. Intramuscular ONFA and BCFA contents were not affected, but their proportions were reduced (P<0.01 and P<0.001) by SO addition, suggesting a dilution effect of the dietary polyunsaturates accumulated in both muscles, except for 17:0i which decreased only in Longissimus lumborum due to significant (P<0.05) soybean oilxmuscle interaction. The higher (P<0.05) BCFA contents and the FA profile in Biceps femoris were not affected by fatness, indicating an association with other muscle properties. The present study supplies new information on ONFA and BCFA in rabbit meat.

Diet digestibility in growing rabbits: effect of origin and oxidation level of dietary fat and vitamin e supplementation

The effects of the dietary inclusion of fats with different origin (lard or vegetal oil), fatty acid profile (linseed or sunflower), oxidation level (fresh, peroxidised: 11 d at 55ºC or oxidised: 31 h at 140ºC) and vitamin E supplementation (0 or 100 ppm) on the rabbit diet apparent digestibility were studied. Digestibility coefficients of dry matter, organic matter, crude protein, ether extract and gross energy were determined in eight diets using 58 rabbits aged 49 d. Contrast analysis between groups of diets showed that lard, characterised by a greater saturated fatty acid content, compared with vegetal oils, rich in unsaturated fatty acid, reduced the apparent digestibility of ether extract (62.3 vs. 68.4%; P=0.0329). However, there were no significant differences in the nutrient digestibility when linseed or sunflower oils (rich in ω-3 or in ω-6 polyunsaturated fatty acids, respectively) were compared. The oxidation degree of the sunflower oil and the supplementation with 100 ppm of vitamin E to the diets did not modify the apparent digestibility values of any dietary fraction. <br />Key Words: rabbit, fat, ω-3/ω-6 fatty acids, oxidation level, tocopherol, digestibility.

New hypotheses for the health-protective mechanisms of whole-grain cereals: what is beyond fibre?

Epidemiological studies have clearly shown that whole-grain cereals can protect against obesity, diabetes, CVD and cancers. The specific effects of food structure (increased satiety, reduced transit time and glycaemic response), fibre (improved faecal bulking and satiety, viscosity and SCFA production, and/or reduced glycaemic response) and Mg (better glycaemic homeostasis through increased insulin secretion), together with the antioxidant and anti-carcinogenic properties of numerous bioactive compounds, especially those in the bran and germ (minerals, trace elements, vitamins, carotenoids, polyphenols and alkylresorcinols), are today well-recognised mechanisms in this protection. Recent findings, the exhaustive listing of bioactive compounds found in whole-grain wheat, their content in whole-grain, bran and germ fractions and their estimated bioavailability, have led to new hypotheses. The involvement of polyphenols in cell signalling and gene regulation, and of sulfur compounds, lignin and phytic acid should be considered in antioxidant protection. Whole-grain wheat is also a rich source of methyl donors and lipotropes (methionine, betaine, choline, inositol and folates) that may be involved in cardiovascular and/or hepatic protection, lipid metabolism and DNA methylation. Potential protective effects of bound phenolic acids within the colon, of the B-complex vitamins on the nervous system and mental health, of oligosaccharides as prebiotics, of compounds associated with skeleton health, and of other compounds such as alpha-linolenic acid, policosanol, melatonin, phytosterols and para-aminobenzoic acid also deserve to be studied in more depth. Finally, benefits of nutrigenomics to study complex physiological effects of the 'whole-grain package', and the most promising ways for improving the nutritional quality of cereal products are discussed.

Foodborne Salmonella ecology in the avian gastrointestinal tract

Foodborne Salmonella continues to be a major cause of salmonellosis with Salmonella Enteritidis and S. Typhimurium considered to be responsible for most of the infections. Investigation of outbreaks and sporadic cases has indicated that food vehicles such as poultry and poultry by-products including raw and uncooked eggs are among the most common sources of Salmonella infections. The dissemination and infection of the avian intestinal tract remain somewhat unclear. In vitro incubation of Salmonella with mammalian tissue culture cells has shown that invasion into epithelial cells is complex and involves several genetic loci and host factors. Several genes are required for the intestinal phase of Salmonella invasion and are located on Salmonella pathogenicity island 1 (SPI 1). Salmonella pathogenesis in the gastrointestinal (GI) tract and the effects of environmental stimuli on gene expression influence bacterial colonization and invasion. Furthermore, significant parameters of Salmonella including growth physiology, nutrient availability, pH, and energy status are considered contributing factors in the GI tract ecology. Approaches for limiting Salmonella colonization have been primarily based on the microbial ecology of the intestinal tract. In vitro studies have shown that the toxic effects of short chain fatty acids (SCFA) to some Enterobacteriaceae, including Salmonella, have resulted in a reduction in population. In addition, it has been established that native intestinal microorganisms such as Lactobacilli provide protective mechanisms against Salmonella in the ceca. A clear understanding of the key factors involved in Salmonella colonization in the avian GI tract has the potential to lead to better approach for more effective control of this foodborne pathogen.