Nutrient requirements of dairy cattle , Nutrient requirements of dairy cattle , مرکز فناوری اطلاعات و اطلاع رسانی کشاورزی

Nutrient requirements of dairy cattle

The aflatoxin producing fungi, Aspergillus spp., are widely spread in nature and have severely contaminated food supplies of humans and animals, resulting in health hazards and even death. Therefore, there is great demand for aflatoxins research to develop suitable methods for their quantification, precise detection and control to ensure the safety of consumers’ health. Here, the chemistry and biosynthesis of the mycotoxins is discussed their occurrence and the health hazards to humans and livestock. This review focuses on resources, production, detection and control measures of aflatoxins to ensure food and feed safety. The results presented herein will facilitate health-conscious consumers and for experts, while providing knowledge on new and innovative approaches to ensure food safety and meet the future demands of the increasing population by decreasing the incidence of outbreaks by aflatoxins.

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Aflatoxins: A Global Concern for Food Safety, Human Health and Their Management

Plant roots nurture a tremendous diversity of microbes via exudation of photosynthetically fixed carbon sources. In turn, probiotic members of the root microbiome promote plant growth and protect the host plant against pathogens and pests. In the Arabidopsis thaliana-Pseudomonas simiae WCS417 model system the root-specific transcription factor MYB72 and the MYB72-controlled β-glucosidase BGLU42 emerged as important regulators of beneficial rhizobacteria-induced systemic resistance (ISR) and iron-uptake responses. MYB72 regulates the biosynthesis of iron-mobilizing fluorescent phenolic compounds, after which BGLU42 activity is required for their excretion into the rhizosphere. Metabolite fingerprinting revealed the antimicrobial coumarin scopoletin as a dominant metabolite that is produced in the roots and excreted into the rhizosphere in a MYB72- and BGLU42-dependent manner. Shotgun-metagenome sequencing of root-associated microbiota of Col-0, myb72, and the scopoletin biosynthesis mutant f6'h1 showed that scopoletin selectively impacts the assembly of the microbial community in the rhizosphere. We show that scopoletin selectively inhibits the soil-borne fungal pathogens Fusarium oxysporum and Verticillium dahliae, while the growth-promoting and ISR-inducing rhizobacteria P. simiae WCS417 and Pseudomonas capeferrum WCS358 are highly tolerant of the antimicrobial effect of scopoletin. Collectively, our results demonstrate a role for coumarins in microbiome assembly and point to a scenario in which plants and probiotic rhizobacteria join forces to trigger MYB72/BGLU42-dependent scopolin production and scopoletin excretion, resulting in improved niche establishment for the microbial partner and growth and immunity benefits for the host plant.

https://www.pnas.org/content/pnas/115/22/E5213.full.pdf

MYB72-dependent coumarin exudation shapes root microbiome assembly to promote plant health

Since ochratoxin A (OTA) was discovered, it has been ubiquitous as a natural contaminant of moldy food and feed. The multiple toxic effects of OTA are a real threat for human beings and animal health. For example, OTA can cause porcine nephropathy but can also damage poultries. Humans exposed to OTA can develop (notably by inhalation in the development of acute renal failure within 24 h) a range of chronic disorders such as upper urothelial carcinoma. OTA plays the main role in the pathogenesis of some renal diseases including Balkan endemic nephropathy, kidney tumors occurring in certain endemic regions of the Balkan Peninsula, and chronic interstitial nephropathy occurring in Northern African countries and likely in other parts of the world. OTA leads to DNA adduct formation, which is known for its genotoxicity and carcinogenicity. The present article discusses how renal carcinogenicity and nephrotoxicity cause both oxidative stress and direct genotoxicity. Careful analyses of the data show that OTA carcinogenic effects are due to combined direct and indirect mechanisms (e.g., genotoxicity, oxidative stress, epigenetic factors). Altogether this provides strong evidence that OTA carcinogenicity can also occur in humans.

https://www.mdpi.com/2072-6651/8/7/191/pdf

Ochratoxin A: 50 Years of Research

Heat as a stressor of poultry has been studied extensively for many decades; it affects poultry production on a worldwide basis and has significant impact on well-being and production. More recently, the involvement of heat stress in inducing oxidative stress has received much interest. Oxidative stress is defined as the presence of reactive species in excess of the available antioxidant capacity of animal cells. Reactive species can modify several biologically cellular macromolecules and can interfere with cell signaling pathways. Furthermore, during the last decade, there has been an ever-increasing interest in the use of a wide array of natural feed-delivered phytochemicals that have potential antioxidant properties for poultry. In light of this, the current review aims to (1) summarize the mechanisms through which heat stress triggers excessive superoxide radical production in the mitochondrion and progresses into oxidative stress, (2) illustrate that this pathophysiology is dependent on the intensity and duration of heat stress, (3) present different nutritional strategies for mitigation of mitochondrial dysfunction, with particular focus on antioxidant phytochemicals. Oxidative stress that occurs with heat exposure can be manifest in all parts of the body; however, mitochondrial dysfunction underlies oxidative stress. In the initial phase of acute heat stress, mitochondrial substrate oxidation and electron transport chain activity are increased resulting in excessive superoxide production. During the later stage of acute heat stress, down-regulation of avian uncoupling protein worsens the oxidative stress situation causing mitochondrial dysfunction and tissue damage. Typically, antioxidant enzyme activities are upregulated. Chronic heat stress, however, leads to downsizing of mitochondrial metabolic oxidative capacity, up-regulation of avian uncoupling protein, a clear alteration in the pattern of antioxidant enzyme activities, and depletion of antioxidant reserves. Some phytochemicals, such as various types of flavonoids and related compounds, were shown to be beneficial in chronic heat-stressed poultry, but were less or not effective in non-heat-stressed counterparts. This supports the contention that antioxidant phytochemicals have potential under challenging conditions. Though substantial progress has been made in our understanding of the association between heat stress and oxidative stress, the means by which phytochemicals can alleviate oxidative stress have been sparsely explored.

https://biblio.ugent.be/publication/8518014/file/8519404.pdf

Association between heat stress and oxidative stress in poultry; mitochondrial dysfunction and dietary interventions with phytochemicals.

Aflatoxin B1 (AFB1) is one of the most harmful mycotoxins in animal production and food industry. A safe, effective and environmentally sound detoxification method is needed for controlling this toxin. In this study, 65 samples were screened from various sources with vast microbial populations using a newly developed medium containing coumarin as the sole carbon source. Twenty five single-colony bacterial isolates showing AFB1 reduction activity in a liquid culture medium were selected from the screen. Isolate 35-3, obtained from tapir feces and identified to be Stenotrophomonas maltophilia, reduced AFB1 by 82.5% after incubation in the liquid medium at 37 °C for 72 h. The culture supernatant of isolate 35-3 was able to degrade AFB1 effectively, whereas the viable cells and cell extracts were far less effective. Factors influencing AFB1 degradation by the culture supernatant were investigated. Activity was reduced to 60.8% and 63.5% at 20 °C and 30 °C, respectively, from 78.7% at 37 °C. The highest degradation rate was 84.8% at pH 8 and the lowest was only 14.3% at pH 4.0. Ions Mg2+ and Cu2+ were activators for AFB1 degradation, however，ion Zn2+ was a strong inhibitor. Treatments with proteinase K, proteinase K plus SDS and heating significantly reduced or eradicated the degradation activity of the culture supernatant. The results indicated that the degradation of AFB1 by S. maltophilia 35-3 was enzymatic and could have a great potential in industrial applications.

https://www.mdpi.com/1422-0067/9/8/1489/pdf

Aflatoxin B1 Degradation by Stenotrophomonas Maltophilia and Other Microbes Selected Using Coumarin Medium

Bacillus subtilis ANSB060 isolated from fish gut is very effective in detoxifying aflatoxins in feed and feed ingredients. The purpose of this research was to investigate the effects of B. subtilis ANSB060 on growth performance, body antioxidant functions, and aflatoxin residues in ducks fed moldy maize naturally contaminated with aflatoxins. A total of 1500 18-d-old male Cherry Valley ducks with similar body weight were randomly assigned to five treatments with six replicates of 50 ducks per repeat. The experiment design consisted of five dietary treatments labeled as C0 (basal diet containing 60% normal maize), M0 (basal diet containing 60% moldy maize contaminated with aflatoxins substituted for normal maize), M500, M1000, and M2000 (M0 +500, 1000 or 2000 g/t aflatoxin biodegradation preparation mainly consisted of B. subtilis ANSB060). The results showed that ducks fed 22.44 ± 2.46 μg/kg of AFB1 (M0) exhibited a decreasing tendency in average daily gain (ADG) and total superoxide dismutase (T-SOD) activity in serum, and T-SOD and glutathione peroxidase (GSH-Px) activities in the liver significantly decreased along with the appearance of AFB1 and AFM1 compared with those in Group C0. The supplementation of B. subtilis ANSB060 into aflatoxin-contaminated diets increased the ADG of ducks (p > 0.05), significantly improved antioxidant enzyme activities, and reduced aflatoxin accumulation in duck liver. In conclusion, Bacillus subtilis ANSB060 in diets showed an ameliorating effect to duck aflatoxicosis and may be a promising feed additive.

Ameliorating Effects of Bacillus subtilis ANSB060 on Growth Performance, Antioxidant Functions, and Aflatoxin Residues in Ducks Fed Diets Contaminated with Aflatoxins

Aims: To prepare, purify and characterize an extracellular enzyme from Myxococcus fulvus ANSM068, designated as myxobacteria aflatoxin degradation enzyme (MADE), which possesses degradation activity against aflatoxin B1 (AFB1), G1 (AFG1) and M1 (AFM1) in solution.

Methods and Results:  The culture supernatant of strain M. fulvus demonstrated high degradation ability against AFB1 (71·89%), AFG1 (68·13%) and AFM1 (63·82%) after 48 h of incubation. An enzyme was purified from the supernatant of M. fulvus using ethanol precipitation and chromatography on DEAE-Sepharose and Superdex 75. An overall 166-fold purification of the enzyme with a recovery of 57% and a final specific activity of 569·44 × 103 U mg−1 was obtained using the present purification protocol. The apparent molecular mass of MADE was estimated to be 32 kDa by SDS-PAGE. AFG1 and AFM1 were significantly degraded, by 96·96 and 95·80%, respectively, when treated with pure MADE (100 U ml−1) produced by strain ANSM068. MADE exhibited the largest amount of activity at 35°C and pH 6·0, with Mg2+ ions greatly promoting and Zn2+ strongly inhibiting MADE activity.

Conclusions:  An aflatoxin degradation enzyme from bacterial isolates can effectively remove aflatoxin B1, G1 and M1 in solution.

Significance and Impact of the Study:  The high activity and wide temperature and pH range of MADE for the degradation of aflatoxin have promising applications in control of mycotoxins during food and feed processing.

https://onlinelibrary.wiley.com/doi/pdf/10.1111/j.1365-2672.2010.04867.x

Preparation, purification and characteristics of an aflatoxin degradation enzyme from Myxococcus fulvus ANSM068

Aflatoxins are commonly found in cereals worldwide and bring significant threats to the food industry and animal production. The aim of this research was to search for Bacillus subtilis from animals’ guts and soil capable of transforming aflatoxin B1, M1, and G1 simultaneously. In addition, the selected B. subtilis can inhibit the growth of pathogen and resist to unfavorable conditions within simulated gut environments. High-performance liquid chromatography was used to determine the reduction in aflatoxin concentrations. B. subtilis ANSB060 from fish gut had the strongest ability to detoxify toxins, and percentages of aflatoxin B1, M1, and G1 degradation were 81.5%, 60%, and 80.7%, respectively. Moreover, the results implied that the activity of aflatoxins degradation was mainly in the culture supernatant of ANSB060 rather than its cells or cell extracts. And ANSB060 showed antimicrobial activities against Escherichia coli, Salmonella typhimurium, Staphylococcus aureus and resistance to the simulated gut environments. This research indicated that the degradation of aflatoxins by ANSB060 could have a great potential in industrial applications.

Qiugang Ma

Papers

Aflatoxin B1 Degradation by Stenotrophomonas Maltophilia and Other Microbes Selected Using Coumarin Medium

Ameliorating Effects of Bacillus subtilis ANSB060 on Growth Performance, Antioxidant Functions, and Aflatoxin Residues in Ducks Fed Diets Contaminated with Aflatoxins

Preparation, purification and characteristics of an aflatoxin degradation enzyme from Myxococcus fulvus ANSM068

Isolation of Bacillus subtilis: screening for aflatoxins B1, M1, and G1 detoxification

Development of breast muscle and meat quality in Arbor Acres broilers, Jingxing 100 crossbred chickens and Beijing fatty chickens.