Marandu grass management and supplementation on performance and methane mitigation of Nellore bulls

Pós-graduação em Zootecnia - FCAV

Exercise and oxidative stress: p,otential effects of antioxidant dietary strategies in sports

Free radicals are produced during aerobic cellular metabolism and have key roles as regulatory mediators in signaling processes. Oxidative stress reflects an imbalance between production of reactive oxygen species and an adequate antioxidant defense. This adverse condition may lead to cellular and tissue damage of components, and is involved in different physiopathological states, including aging, exercise, inflammatory, cardiovascular and neurodegenerative diseases, and cancer. In particular, the relationship between exercise and oxidative stress is extremely complex, depending on the mode, intensity, and duration of exercise. Regular moderate training appears beneficial for oxidative stress and health. Conversely, acute exercise leads to increased oxidative stress, although this same stimulus is necessary to allow an up-regulation in endogenous antioxidant defenses (hormesis). Supporting endogenous defenses with additional oral antioxidant supplementation may represent a suitable noninvasive tool for preventing or reducing oxidative stress during training. However, excess of exogenous antioxidants may have detrimental effects on health and performance. Whole foods, rather than capsules, contain antioxidants in natural ratios and proportions, which may act in synergy to optimize the antioxidant effect. Thus, an adequate intake of vitamins and minerals through a varied and balanced diet remains the best approach to maintain an optimal antioxidant status. Antioxidant supplementation may be warranted in particular conditions, when athletes are exposed to high oxidative stress or fail to meet dietary antioxidant requirements. Aim of this review is to discuss the evidence on the relationship between exercise and oxidative stress, and the potential effects of dietary strategies in athletes. The differences between diet and exogenous supplementation as well as available tools to estimate effectiveness of antioxidant intake are also reported. Finally, we advocate the need to adopt an individualized diet for each athlete performing a specific sport or in a specific period of training, clinically supervised with inclusion of blood analysis and physiological tests, in a comprehensive nutritional assessment. (C) 2015 Elsevier Inc. All rights reserved.

In vitro evaluation, in vivo quantification, and microbial diversity studies of nutritional strategies for reducing enteric methane production

The main objective of the present work was to study nutritive strategies for lessening the CH4 formation associated to ruminant tropical diets. In vitro gas production technique was used for evaluating the effect of tannin-rich plants, essential oils, and biodiesel co-products on CH4 formation in three individual studies and a small chamber system to measure CH4 released by sheep for in vivo studies was developed. Microbial rumen population diversity from in vitro assays was studied using qPCR. In vitro studies with tanniniferous plants, herbal plant essential oils derived from thyme, fennel, ginger, black seed, and Eucalyptus oil (EuO) added to the basal diet and cakes of oleaginous plants (cotton, palm, castor plant, turnip, and lupine), which were included in the basal diet to replace soybean meal, presented significant differences regarding fermentation gas production and CH4 formation. In vivo assays were performed according to the results of the in vitro assays. , when supplemented to a basal diet (Tifton-85 hay sp, corn grain, soybean meal, cotton seed meal, and mineral mixture) fed to adult Santa Ines sheep reduced enteric CH4 emission but the supplementation of the basal diet with EuO did not affect ( > 0.05) methane released. Regarding the microbial studies of rumen population diversity using qPCR with DNA samples collected from the in vitro trials, the results showed shifts in microbial communities of the tannin-rich plants in relation to control plant. This research demonstrated that tannin-rich , essential oil from eucalyptus, and biodiesel co-products either in vitro or in vivo assays showed potential to mitigate CH4 emission in ruminants. The microbial community study suggested that the reduction in CH4 production may be attributed to a decrease in fermentable substrate rather than to a direct effect on methanogenesis.

Nutritional strategies to control mycotoxin damages in swine

Mycotoxins are contaminants of agricultural products both in the field and during storage and can enter the food chain through contaminated cereals and foods (milk, meat, and eggs) obtained from animals fed mycotoxin contaminated feeds. Mycotoxins are genotoxic carcinogens that cause health and economic problems. Ochratoxin A and fumonisin B1 have been classified by the International Agency for Research on Cancer in 1993, as “possibly carcinogenic to humans” (class 2B). To control mycotoxins induced damages, different strategies have been developed to reduce the growth of mycotoxigenic fungi as well as to decontaminate and/or detoxify mycotoxin contaminated foods and animal feeds. Critical points, target for these strategies, are: prevention of mycotoxin contamination, detoxification of mycotoxins already present in food and feed, inhibition of mycotoxin absorption in the gastrointestinal tract, reduce mycotoxin induced damages when absorption occurs. Decontamination processes, as indicate by FAO, needs the following requisites to reduce toxic and economic impact of mycotoxins: it must destroy, inactivate, or remove mycotoxins; it must not produce or leave toxic and/or carcinogenic/mutagenic residues in the final products or in food products obtained from animals fed decontaminated feed; it must be capable of destroying fungal spores and mycelium in order to avoiding mycotoxin formation under favorable conditions; it should not adversely affect desirable physical and sensory properties of the feedstuff; it has to be technically and economically feasible. One important approach to the prevention of mycotoxicosis in livestock is the addition in the diets of the non-nutritionally adsorbents that bind mycotoxins preventing the absorption in the gastrointestinal tract. Activated carbons, hydrated sodium calcium aluminosilicate (HSCAS), zeolites, bentonites, and certain clays, are the most studied adsorbent and they possess a high affinity for mycotoxins. In recent years, there has been increasing interest on the hypothesis that the absorption in consumed food can be inhibited by microorganisms in the gastrointestinal tract. Numerous investigators showed that some dairy strains of LAB and bifidobacteria were able to bind aflatoxins effectively. There is a strong need for prevention of the mycotoxin-induced damages once the toxin is ingested. Nutritional approaches, such as supplementation of nutrients, food components, or additives with protective effects against mycotoxin toxicity are assuming increasing interest. Since mycotoxins have been known to produce damages by increasing oxidative stress, the protective properties of antioxidant substances have been extensively investigated. Purpose of the present study was to investigate in vitro and in vivo, strategies to counteract mycotoxin threat particularly in swine husbandry. The Ussing chambers technique was applied in the present study that for the first time to investigate in vitro the permeability of OTA and FB1 through rat intestinal mucosa. Results showed that OTA and FB1 were not absorbed from rat small intestine mucosa. Since in vivo absorption of both mycotoxins normally occurs, it is evident that in these experimental conditions Ussing diffusion chambers were not able to assess the intestinal permeability of OTA and FB1. A large number of LAB strains isolated from feces and different gastrointestinal tract regions of pigs and poultry were screened for their ability to remove OTA, FB1, and DON from bacterial medium. Results of this in vitro study showed low efficacy of isolated LAB strains to reduce OTA, FB1, and DON from bacterial medium. An in vivo trial in rats was performed to evaluate the effects of in-feed supplementation of a LAB strain, Pediococcus pentosaceus FBB61, to counteract the toxic effects induced by exposure to OTA contaminated diets. The study allows to conclude that feed supplementation with P. pentosaceus FBB61 ameliorates the oxidative status in liver, and lowers OTA induced oxidative damage in liver and kidney if diet was contaminated by OTA. This P. pentosaceus FBB61 feature joined to its bactericidal activity against Gram positive bacteria and its ability to modulate gut microflora balance in pigs, encourage additional in vivo experiments in order to better understand the potential role of P. pentosaceus FBB61 as probiotic for farm animals and humans. In the present study, in vivo trial on weaned piglets fed FB1 allow to conclude that feeding of 7.32 ppm of FB1 for 6 weeks did not impair growth performance. Deoxynivalenol contamination of feeds was evaluated in an in vivo trial on weaned piglets. The comparison between growth parameters of piglets fed DON contaminated diet and contaminated diet supplemented with the commercial product did not reach the significance level but piglet growth performances were numerically improved when the commercial product was added to DON contaminated diet. Further studies are needed to improve knowledge on mycotoxins intestinal absorption, mechanism for their detoxification in feeds and foods, and nutritional strategies to reduce mycotoxins induced damages in animals and humans. The multifactorial approach acting on each of the various steps could be a promising strategy to counteract mycotoxins damages.

Dietary strategies to minimize the detrimental impact of weaning on gut morphology, physiology and microbiota of piglets

Weaning is a crucial period in the management of piglets. In modern piggeries economic interest make weaning age decrease more and more and the detrimental consequences of weaning have as much importance as earlier the weaning occurs. The risk of development of post-weaning diarrhea (PWD) in piglets is high and PWD is the cause of serious economic losses in pig herds. In the past the supplementation of the feed given after weaning with growth promoters antibiotics, in order to keep PWD under control, used to be a common practice, but their usage has been banned in EU since 2006. This measure led to the investigation of alternative suitable feed supplements that would be reasonably efficient in protecting and sustaining animal health and performance. Aim of this thesis was to evaluate the effect of some different alternatives to growth-promoters antibiotics on weaning piglets and to assess if some of them could be considered as valuables options to replace auxinic in animal feeding. The study is composed by four experimental trials. The first one aims to identify mechanisms involved in the auxinic effects of antibiotics in the diets; the following three evaluate the addition butyric acid, tryptophan, and nitrate as alternative to in-feed antimicrobials. Although some results are controversial, it appears from the data presented that the alternatives to in-feed antibiotics considered may exert positive effects on some zootechnical and health parameters on piglet in the post-weaning period. Anyway, the mechanism of action and the interaction with microbiota of such additives should be investigated inside out because many effects remains poorly understood.

Therapeutic strategies for modulation of the vaginal microbiota

The vaginal microbiota of healthy women consists of a wide variety of anaerobic and aerobic bacteria, dominated by the genus Lactobacillus. The activity of lactobacilli is essential to protect women from genital infections and to maintain the natural healthy balance of the vaginal ecosystem. This role is particularly important during pregnancy because vaginal infection is one of the most important mechanisms for preterm birth. The most common vaginal disorder is bacterial vaginosis (BV). BV is a polymicrobial disorder, characterized by a depletion of lactobacilli and an increase in the concentration of other bacteria, including Gardnerella vaginalis, anaerobic Gram-negative rods, anaerobic Gram-positive cocci, Mycoplasma hominis, and Mobiluncus spp. An integrated molecular approach based on real-time PCR and PCR-DGGE was used to investigate the effects of two different therapeutic approaches on the vaginal microbiota composition. (i) The impact of a dietary supplementation with the probiotic VSL#3, a mixture of Lactobacillus, Bifidobacterium and Streptococcus strains, on the vaginal microbial ecology and immunological profiles of healthy women during late pregnancy was investigated. The intake was associated to a slight modulation of the vaginal microbiota and cytokine secretion, with potential implications in preventing preterm birth. (ii) The efficacy of different doses of the antibiotic rifaximin (100 mg/day for 5 days, 25 mg/day for 5 days, 100 mg/day for 2 days) on the vaginal microbiota of patients with BV enrolled in a multicentre, double-blind, randomised, placebo-controlled study was also evaluated. The molecular analyses demonstrated the ability of rifaximin 25 mg/day for 5 days to induce an increase of lactobacilli and a decrease of the BV-associated bacteria after antibiotic treatment, and a reduction of the complexity of the vaginal microbial communities. Thus, confirming clinical results, it represents the most effective treatment to be used in future pivotal studies for the treatment of BV.

Effects of different nutritional strategies on intestinal inflammation in pigs

Intestinal health is essential for the health of the body since the gastro-intestinal mucosa is the main site of interaction with the external environment, as well as the major area colonized by the microbiota. Intestinal health relies on proper barrier function, epithelial integrity and related mechanisms of protection (mucous layer, tight junctions, immune and inflammatory system). In pigs, during the weaning transition, intestinal inflammation and barrier integrity play a crucial role in regulating intestinal health and, consequently, pig’s health, growth and productivity. The aim of the project was to assess the impact of different nutritional strategies on the intestinal health of weaning piglets with reference to the inflammatory status and epithelial integrity. Therefore, in vivo trials were conducted to test the in-feed supplementation with zinc, tributyrin, or organic acids and nature-identical compounds (NIC) to weaning piglets. All the dietary interventions positively impacted the intestinal inflammatory status and, as a consequence, improved epithelial integrity by modulating tight junctions proteins (zinc or tributyrin) or by enhancing barrier properties measured with Ussing chambers (organic acids and NIC). These findings highlight that intestinal inflammation and barrier function are strictly linked, and that the control of inflammation is essential for adequate barrier function. In addition, in zinc trial and organic acids and NIC trial, better intestinal health could successfully result in better growth performance, as aimed for pig production improvement. To conclude, this work shows that dietary supplementation with bio-active substances such as zinc, tributyrin or organic acids and NIC may improve intestinal health of weaning piglets modulating intestinal inflammatory stress and barrier integrity and allowing better piglet’s health, growth and productivity.

The potential effect of population development, smoking and antioxidant supplementation on the future epidemiology of age-related macular degeneration in Switzerland

BACKGROUND: Due to the predicted age shift of the population an increase in the number of patients with late AMD is expected. At present smoking represents the only modifiable risk factor. Supplementation of antioxidants in patients at risk is the sole effective pharmacological prevention. The aim of this study is to estimate the future epidemiological development of late AMD in Switzerland and to quantify the potential effects of smoking and antioxidants supplementation. METHODS: The modelling of the future development of late AMD cases in Switzerland was based on a meta-analysis of the published data on AMD-prevalence and on published Swiss population development scenarios until 2050. Three different scenarios were compared: low, mean and high. The late AMD cases caused by smoking were calculated using the "population attributable fraction" formula and data on the current smoking habits of the Swiss population. The number of potentially preventable cases was estimated using the data of the Age-Related Eye Disease Study (AREDS). RESULTS: According to the mean population development scenario, late AMD cases in Switzerland will rise from 37 200 cases in 2005 to 52 500 cases in 2020 and to 93 200 cases in 2050. Using the "low" and the "high" scenarios the late AMD cases may range from 49 500 to 56 000 in 2020 and from 73 700 to 118 400 in 2050, respectively. Smoking is responsible for approximately 7 % of all late AMD cases, i. e., 2600 cases in 2005, 3800 cases in 2020, 6600 cases in 2050 ("mean scenario"). With future antioxidant supplementation to all patients at risk another 3100 cases would be preventable until 2020 and possibly 23 500 cases until 2050. CONCLUSION: Due to age shift in the population a 2.5-fold increase in late AMD cases until 2050 is expected, representing a socioeconomic challenge. Cessation of smoking and supplementation of antioxidants to all patients at risk has the potential to reduce this number. Unfortunately, public awareness is low. These data may support health-care providers and public opinion leaders when developing public education and prevention strategies.

The influence of antioxidant supplementation on markers of inflammation and the relationship to oxidative stress after exercise

Interest in the relationship between inflammation and oxidative stress has increased dramatically in recent years, not only within the clinical setting but also in the fields of exercise biochemistry and immunology. Inflammation and oxidative stress share a common role in the etiology of a variety Of Chronic diseases. During exercise, inflammation and oxidative stress are linked via muscle metabolism and muscle damage. Because oxidative stress and inflammation have traditionally been associated with fatigue and impaired recovery from exercise, research has focused on nutritional strategies aimed at reducing these effects. In this review, we have evaluated the findings of studies involving antioxidant supplementation on alterations in markers of inflammation (e.g., cytokines, C-reactive protein and cortisol). This review focuses predominantly on the role of reactive oxygen and nitrogen species generated from muscle metabolism and muscle damage during exercise and on the modulatory effects of antioxidant supplements. Furthermore, we have analyzed the influence of factors such as the dose, timing, supplementation period and bioavailability of antioxidant nutrients. (C) 2007 Elsevier Inc. All rights reserved.

A randomised controlled trial investigating the effect of nutritional supplementation on visual function in normal, and age-related macular disease affected eyes:design and methodology [ISRCTN78467674]

Background: Age-related macular disease is the leading cause of blind registration in the developed world. One aetiological hypothesis involves oxidation, and the intrinsic vulnerability of the retina to damage via this process. This has prompted interest in the role of antioxidants, particularly the carotenoids lutein and zeaxanthin, in the prevention and treatment of this eye disease. Methods: The aim of this randomised controlled trial is to determine the effect of a nutritional supplement containing lutein, vitamins A, C and E, zinc, and copper on measures of visual function in people with and without age-related macular disease. Outcome measures are distance and near visual acuity, contrast sensitivity, colour vision, macular visual field, glare recovery, and fundus photography. Randomisation is achieved via a random number generator, and masking achieved by third party coding of the active and placebo containers. Data collection will take place at nine and 18 months, and statistical analysis will employ Student's t test. Discussion: A paucity of treatment modalities for age-related macular disease has prompted research into the development of prevention strategies. A positive effect on normals may be indicative of a role of nutritional supplementation in preventing or delaying onset of the condition. An observed benefit in the age-related macular disease group may indicate a potential role of supplementation in prevention of progression, or even a degree reversal of the visual effects caused by this condition.