Denovo synthesized fatty acids as regulators of milk fat synthesis

The objectives of the dissertation research were to determine the role of denovo synthesized fatty acids (DNFA) in the regulation of milk fat synthesis. Milk fat responses to increasing amounts of short- and medium-chain fatty acids (SMCFA), added in the proportion as synthesized denovo, were studied in lactating dairy cows. The results showed a significant linear increase in milk fat concentration with SMCFA supplementation. However, milk fat yield was similar for all treatments. A subsequent study was aimed at increasing the availability of SMCFA during trans-10, cis-12 CLA-induced milk fat depression (MFD) in lactating dairy cows to determine whether SMCFA can rescue part of CLA-induced MFD. Post-ruminal infusion of butterfat (BF) was used as a source of SMCFA. The BF treatment was compared to a mixture of fats containing only the long-chain FA (LCFA) with or without trans-10, cis-12 CLA infusion. Milk fat content and yield were significantly reduced with trans-10, cis-12 CLA. However, increased availability of SMCFA with BF infusion had no effects on milk fat yield and concentration. Trans-10, cis-12 CLA significantly reduced the mRNA expression of transcription factor SREBP-1c along with its downstream targets including ACC,FASN, LPL, SCD and AGPAT. The increased availability of SMCFA had no effect on either lipogenic gene or protein expression suggesting that nutritional manipulation was not sufficient to rescue trans-10, cis-12 CLA-induced MFD. Finally, the effects of combination of a Rosiglitazone (ROSI), a PPAR-γ agonist, and trans-10, cis-12 CLA were examined on mammary and hepatic lipogenesis in lactating mice. Mammary lipogenesis was significantly reduced with trans-10, cis-12 CLA, reducing the milk fat content and mRNA expression of lipogenic transcription factors SREBP1-c and PPAR- γ. Trans-10, cis-12 CLA significantly increased hepatic lipid accumulation, while the mRNA expression of SREBP1-c and PPAR- γ were not altered. On the contrary, ROSI had no effects on mammary lipogenesis. However, ROSI significantly rescued trans-10, cis-12 CLA-induced hepatic steatosis

Dietary Conjugated Linoleic Acid and Hepatic Steatosis: Species-Specific Effects on Liver and Adipose Lipid Metabolism and Gene Expression

Objective. To summarize the recent studies on effect of conjugated linoleic acid (CLA) on hepatic steatosis and hepatic and adipose lipid metabolism highlighting the potential regulatory mechanisms. Methods. Sixty-four published experiments were summarized in which trans-10, cis-12 CLA was fed either alone or in combination with other CLA isomers to mice, rats, hamsters, and humans were compared. Summary and Conclusions. Dietary trans-10, cis-12 CLA induces a severe hepatic steatosis in mice with a more muted response in other species. Regardless of species, when hepatic steatosis was present, a concurrent decrease in body adiposity was observed, suggesting that hepatic lipid accumulation is a result of uptake of mobilized fatty acids (FA) from adipose tissue and the liver's inability to sufficiently increase FA oxidation and export of synthesized triglycerides. The potential role of liver FA composition, insulin secretion and sensitivity, adipokine, and inflammatory responses are discussed as potential mechanisms behind CLA-induced hepatic steatosis

Biomarker of Aflatoxin Ingestion: ¹H NMR-Based Plasma Metabolomics of Dairy Cows Fed Aflatoxin B₁ with or without Sequestering Agents

The study applied 1H NMR-based plasma metabolomics to identify candidate biomarkers of aflatoxin B1 (AFB1) ingestion in dairy cows fed no sequestering agents and evaluate the effect of supplementing clay and/or a Saccharomyces cerevisiae fermentation product (SCFP) on such biomarkers. Eight lactating cows were randomly assigned to 1 of 4 treatments in a balanced 4 × 4 Latin square design with 2 squares. Treatments were: control, toxin (T; 1725 µg AFB1/head/day), T with clay (CL; 200 g/head/day), and CL with SCFP (CL + SCFP; 35 g of SCFP/head/day). Cows in T, CL, and CL + SCFP were dosed with AFB1 from d 26 to 30. The sequestering agents were top-dressed from d 1 to 33. On d 30 of each period, 15 mL of blood was taken from the coccygeal vessels and plasma samples were prepared by centrifugation. Compared to the control, T decreased plasma concentrations of alanine, acetic acid, leucine, arginine and valine. In contrast, T increased plasma ethanol concentration 3.56-fold compared to control. Treatment with CL tended to reduce sarcosine concentration, whereas treatment with CL + SCFP increased concentrations of mannose and 12 amino acids. Based on size of the area under the curve (AUC) of receiver operating characteristic and fold change (FC) analyses, ethanol was the most significantly altered metabolite in T (AUC = 0.88; FC = 3.56); hence, it was chosen as the candidate biomarker of aflatoxin ingestion in dairy cows fed no sequestering agent

National Survey of United Kingdom Paediatric Allergy Services.

BACKGROUND: Comprehensive national assessments of paediatric allergy services are rarely undertaken, and have never been undertaken in the United Kingdom. A 2006 survey estimated national capacity at 30,000 adult or paediatric new allergy appointments per year and identified 58 hospital clinics offering a paediatric allergy service. OBJECTIVE: The UK Paediatric Allergy Services Survey was the first comprehensive assessment of UK paediatric allergy service provision. METHODS: All 450 UK hospitals responded to a survey. Paediatric allergy services are provided in 154 lead hospitals with 75 further linked hospitals. All 154 lead paediatric allergy services completed a detailed questionnaire between February 2019 and May 2020. RESULTS: The 154 paediatric allergy services self-define as secondary (126/154, 82%) or tertiary (28/154, 18%) level services. The annual capacity is 85,600 new and 111,400 follow-up appointments. Fifty-eight percent (85/146) of services offer ≤10 new appointments per week (no data provided from 8 services-2 no response, 6 unknown) and 50% (70/139) of the services undertaking challenges undertake ≤2 food or drug challenges per week (no data from 3 challenge services). Intramuscular adrenaline is rarely used during challenges-median annual frequency 0 in secondary services and 2 in tertiary services. Allergen-specific immunotherapy is offered in 39% (60/154) of services, with 71% (41/58) of these centres treating ≤10 patients per annum (no data from 2 immunotherapy services). The 12 largest services see 31% of all new paediatric allergy appointments, undertake 51% of new immunotherapy patient provision and 33% of food or drug challenges. Seventy percent (97/126) of secondary and all tertiary services are part of a regional paediatric allergy network. Only nine services offer immunotherapy for any food (3 for peanut), 10 drug desensitization and 18 insect venom immunotherapy. CONCLUSIONS: There has been a fourfold increase in paediatric allergy clinics and an approximately sevenfold increase in new patient appointment numbers in the United Kingdom over the past 15 years. Most services are small, with significant regional variation in availability of specific services such as allergen immunotherapy. Our findings emphasize the need for national standards, local networks and simulation training to ensure consistent and safe service provision

Copper sulfate and sodium selenite lipid-microencapsulation modifies ruminal microbial fermentation in a dual-flow continuous-culture system

La Universidad de Costa Rica proporcionó una beca para el programa de doctorado de José Alberto Arce Cordero.Undesirable interactions between trace mineral ele ments and ruminal contents may occur during digestion when mineral salts are supplemented. Antimicrobial effects of copper sulfate (CuSO4) may affect ruminal digestibility of nutrients when fed as a source of copper (Cu), while sodium selenite (Na2SeO3) may be reduced in the rumen to less available forms of selenium (Se). Our objective was to evaluate if protection of CuSO4 and Na2SeO3 by lipid-microencapsulation would induce changes on ruminal microbial fermentation. We used 8 fermentors in a dual-flow continuous-culture system in a 4 × 4 duplicated Latin square with a 2 × 2 factorial arrangement of treatments. Factors were CuSO4 pro tection (unprotected and protected by lipid-microen capsulation) and Na2SeO3 protection (unprotected and protected by lipid-microencapsulation). Treatments consisted of supplementation with 15 mg/kg of Cu and 0.3 mg/kg of Se from either unprotected or protected (lipid-microencapsulated) sources, as follows: (1) Con trol (unprotected CuSO4 + unprotected Na2SeO3); (2) Cu-P (protected CuSO4 + unprotected Na2SeO3); (3) Se-P (unprotected CuSO4 + protected Na2SeO3); (4) (Cu+Se)-P (protected CuSO4 + protected Na2SeO3). All diets had the same nutrient composition and fer mentors were fed 106 g of dry matter/d. Each experi mental period was 10 d (7 d of adaptation and 3 d for sample collections). Daily pooled samples of effluents were analyzed for pH, NH3-N, nutrient digestibility, and flows (g/d) of total N, NH3-N, nonammonia N (NAN), bacterial N, dietary N, and bacterial efficiency. Kinetics of volatile fatty acids was analyzed in samples collected daily at 0, 1, 2, 4, 6, and 8 h after feeding. Main effects of Cu protection, Se protection, and their interaction were tested for all response variables. Kinetics data were analyzed as repeated measures. Protection of Cu decreased acetate molar proportion, increased butyrate proportion, and tended to decrease acetate:propionate ratio in samples of kinetics, but did not modify nutrient digestibility. Protection of Se tended to decrease NH3-N concentration, NH3-N flow, and CP digestibility; and to increase flows of nonammonia N and dietary N. Our results indicate that protection of CuSO4 may increase butyrate concentration at expenses of acetate, while protection of Na2SeO3 tended to reduce ruminal deg radation of N. Further research is needed to determine the effects of lipid-microencapsulation on intestinal ab sorption, tissue distribution of Cu and Se, and animal performance.UCR::Vicerrectoría de Docencia::Ciencias Agroalimentarias::Facultad de Ciencias Agroalimentarias::Escuela de Zootecni

An expansin-like protein expands forage cell walls and synergistically increases hydrolysis, digestibility and fermentation of livestock feeds by fibrolytic enzymes.

Bacterial expansin-like proteins have synergistically increased cellulose hydrolysis by cellulolytic enzymes during the initial stages of biofuel production, but they have not been tested on livestock feeds. The objectives of this study were to: isolate and express an expansin-like protein (BsEXLX1), to verify its disruptive activity (expansion) on cotton fibers by immunodetection (Experiment 1), and to determine the effect of dose, pH and temperature for BsEXLX1 and cellulase to synergistically hydrolyze filter paper (FP) and carboxymethyl cellulose (CMC) under laboratory (Experiment 2) and simulated ruminal (Experiment 3) conditions. In addition, we determined the ability of BsEXLX1 to synergistically increase hydrolysis of corn and bermudagrass silages by an exogenous fibrolytic enzyme (EFE) (Experiment 4) and how different doses of BsEXLX1 and EFE affect the gas production (GP), in vitro digestibility and fermentation of a diet for dairy cows (Experiment 5). In Experiment 1, immunofluorescence-based examination of cotton microfiber treated without or with recombinant expansin-like protein expressed from Bacillus subtilis (BsEXLX1) increased the surface area by > 100% compared to the untreated control. In Experiment 2, adding BsEXLX1 (100 μg/g FP) to cellulase (0.0148 FPU) increased release of reducing sugars compared to cellulase alone by more than 40% (P < 0.01) at optimal pH (4.0) and temperature (50°C) after 24 h. In Experiment 3 and 4, adding BsEXLX1 to cellulase or EFE, synergistically increased release of reducing sugars from FP, corn and bermudagrass silages under simulated ruminal conditions (pH 6.0, 39°C). In Experiment 5, increasing the concentration of BsEXLX1 linearly increased (P < 0.01) GP from fermentation of a diet for dairy cows by up to 17.8%. Synergistic effects between BsEXLX1 and EFE increased in vitro NDF digestibility of the diet by 23.3% compared to the control. In vitro digestibility of hemicellulose and butyrate concentration were linearly increased by BsEXLX1 compared to the control. This study demonstrated that BsEXLX1 can improve the efficacy of cellulase and EFE at hydrolyzing pure substrates and dairy cow feeds, respectively

Effects of partially replacing dietary corn with molasses, condensed whey permeate, or treated condensed whey permeate on ruminal microbial fermentation

Corn is a feedstuff commonly fed to dairy cows as a source of energy. The objective of this study was to evaluate whether partially replacing dietary corn with molasses or condensed whey permeate, in lactating dairy cow diets in a dual-flow continuous culture system, can maintain nutrient digestibility by ruminal microorganisms. Furthermore, this study evaluated whether treating condensed whey permeate before feeding could aid the fermentation of the condensed whey permeate in the rumen. Eight fermentors were used in a 4 × 4 replicated Latin square with 4 periods of 10 d each. The control diet (CON) was formulated with corn grain, and the other diets were formulated by replacing corn grain with either sugarcane molasses (MOL), condensed whey permeate (CWP), or treated condensed whey permeate (TCWP). Diets were formulated by replacing 4% of the diet dry matter (DM) in the form of starch from corn with sugars from the byproducts. Sugars were defined as water-soluble carbohydrates (WSC) in the rations. The fermentors were fed 52 g of DM twice daily of diets containing 17% crude protein, 28% neutral detergent fiber, and 45% nonfiber carbohydrates. Liquid treatments were pipetted into each fermentor. After 7 d of adaptation, samples were collected for analyses of volatile fatty acids (VFA), lactate, and ammonia, and fermentors’ pH were measured at time points after the morning feeding for 3 d. Pooled samples from effluent containers were collected for similar analyses, nutrient flow, and N metabolism. Data were statistically analyzed using Proc MIXED of SAS version 9.4 (SAS Institute Inc.); fixed effects included treatment and time, and random effects included fermentor, period, and square. The interaction of treatment and time was included for the kinetics samples. The TCWP and MOL treatments maintained greater fermentor pH compared with CWP. Total VFA concentration was increased in CWP compared with MOL. The acetate:propionate ratio was increased in TCWP compared with CON, due to tendencies of increased acetate molar proportion and decreased propionate molar proportion in TCWP. Lactate concentration was increased in MOL. Digestibility of WSC was increased in the diets that replaced corn with byproducts. The partial replacement of 4% of DM from corn starch with the sugars in byproducts had minimal effects on ruminal microbial fermentation and increased pH. Treated CWP had similar effects to molasses.UCR::Vicerrectoría de Docencia::Ciencias Agroalimentarias::Facultad de Ciencias Agroalimentarias::Escuela de Zootecni

The Effects of Incremental Doses of Aflatoxin B1 on In Vitro Ruminal Nutrient Digestibility and Fermentation Profile of a Lactating Dairy Cow Diet in a Dual-Flow Continuous Culture System

Aflatoxin B1 (AFB1 ) is a mycotoxin known to impair human and animal health. It is also believed to have a deleterious effect on ruminal nutrient digestibility under in vitro batch culture systems. The objective of this study was to evaluate the effects of increasing the dose of AFB1 on ruminal dry matter and nutrient digestibility, fermentation profile, and N flows using a dual-flow continuous culture system fed a diet formulated for lactating dairy cows. Eight fermenter vessels were used in a replicated 4 × 4 Latin square design with 10 d periods (7 d adaptation and 3 d sample collection). Treatments were randomly applied to fermenters on diet DM basis: (1) 0 µg of AFB1/kg of DM (Control); (2) 50 µg of AFB1/kg of DM (AF50); (3) 100 µg of AFB1/kg of DM (AF100); and (4) 150 µg of AFB1/kg of DM (AF150). Treatments did not affect nutrient digestibility, fermentation, and N flows. Aflatoxin B1 concentration in ruminal fluid increased with dose but decreased to undetectable levels after 4 h post-dosing. In conclusion, adding incremental doses of AFB1 did not affect ruminal fermentation, digestibility of nutrients, and N flows in a dual-flow continuous culture system fed diets formulated for lactating dairy cows.UCR::Vicerrectoría de Docencia::Ciencias Agroalimentarias::Facultad de Ciencias Agroalimentarias::Escuela de Zootecni