Natural vitamin C intake and the risk of head and neck cancer : a pooled analysis in the International Head and Neck Cancer Epidemiology Consortium

Evidence of associations between single nutrients and head and neck cancer (HNC) is still more limited and less consistent than that for fruit and vegetables. However, clarification of the protective mechanisms of fruit and vegetables is important to our understanding of HNC etiology. We investigated the association between vitamin C intake from natural sources and cancer of the oral cavity/pharynx and larynx using individual-level pooled data from ten case-control studies (5,959 cases and 12,248 controls) participating in the International Head and Neck Cancer Epidemiology (INHANCE) consortium. After harmonization of study-specific exposure information via the residual method, adjusted odds ratios (ORs) and corresponding 95% confidence intervals (CIs) were estimated using unconditional multiple logistic regression models on quintile categories of 'non-alcohol energy-adjusted' vitamin C intake. In the presence of heterogeneity of the estimated ORs among studies, we derived those estimates from generalized linear mixed models. Higher intakes of vitamin C were inversely related to oral and pharyngeal (OR = 0.54, 95% CI: 0.45-0.65, for the fifth quintile category versus the first one, p for trend<0.001) and laryngeal cancers (OR = 0.52, 95% CI: 0.40-0.68, p for trend = 0.006), although in the presence of heterogeneity among studies for both sites. Inverse associations were consistently observed for the anatomical subsites of oral and pharyngeal cancer, and across strata of age, sex, education, body mass index, tobacco, and alcohol, for both cancer sites. The inverse association of vitamin C intake from foods with HNC may reflect a protective effect on these cancers; however, we cannot rule out other explanations.

On-line determination of residual collector concentration in flotation process

Valuable minerals can be recovered by using froth flotation. This is a widely used separation technique in mineral processing. In a flotation cell hydrophobic particles attach on air bubbles dispersed in the slurry and rise on the top of the cell. Valuable particles are made hydrophobic by adding collector chemicals in the slurry. With the help of a frother reagent a stable froth forms on the top of the cell and the froth with valuable minerals, i.e. the concentrate, can be removed for further processing. Normally the collector is dosed on the basis of the feed rate of the flotation circuit and the head grade of the valuable metal. However, also the mineral composition of the ore affects the consumption of the collector, i.e. how much is adsorbed on the mineral surfaces. Therefore it is worth monitoring the residual collector concentration in the flotation tailings. Excess usage of collector causes unnecessary costs and may even disturb the process. In the literature part of the Master’s thesis the basics of flotation process and collector chemicals are introduced. Capillary electrophoresis (CE), an analytical technique suitable for detecting collector chemicals, is also reviewed. In the experimental part of the thesis the development of an on-line CE method for monitoring the concentration of collector chemicals in a flotation process and the results of a measurement campaign are presented. It was possible to determine the quality and quantity of collector chemicals in nickel flotation tailings at a concentrator plant with the developed on-line CE method. Sodium ethyl xanthate and sodium isopropyl xanthate residuals were found in the tailings and slight correlation between the measured concentrations and the dosage amounts could be seen.

Near infrared reflectance spectroscopy (NIRS) to predict biological parameters of maize silage: effects of particle comminution, oven drying temperature and the presence of residual moisture

Maize silage nutritive quality is routinely determined by near infrared reflectance spectroscopy (NIRS). However, little is known about the impact of sample preparation on the accuracy of the calibration to predict biological traits. A sample population of 48 maize silages representing a wide range of physiological maturities was used in a study to determine the impact of different sample preparation procedures (i.e., drying regimes; the presence or absence of residual moisture; the degree of particle comminution) on resultant NIR prediction statistics. All silages were scanned using a total of 12 combinations of sample pre-treatments. Each sample preparation combination was subjected to three multivariate regression techniques to give a total of 36 predictions per biological trait. Increased sample preparations procedure, relative to scanning the unprocessed whole plant (WP) material, always resulted in a numerical minimisation of model statistics. However, the ability of each of the treatments to significantly minimise the model statistics differed. Particle comminution was the most important factor, oven-drying regime was intermediate, and residual moisture presence was the least important. Models to predict various biological parameters of maize silage will be improved if material is subjected to a high degree of particle comminution (i.e., having been passed through a 1 mm screen) and developed on plant material previously dried at 60 degrees C. The extra effort in terms of time and cost required to remove sample residual moisture cannot be justified. (c) 2005 Elsevier B.V. All rights reserved.

Evaluation of NRC, UC Davis and ADAS approaches to estimate the metabolizable energy values of feeds at maintenance energy intake from equations utilizing chemical assays and in vitro determinations

Feed samples received by commercial analytical laboratories are often undefined or mixed varieties of forages, originate from various agronomic or geographical areas of the world, are mixtures (e.g., total mixed rations) and are often described incompletely or not at all. Six unified single equation approaches to predict the metabolizable energy (ME) value of feeds determined in sheep fed at maintenance ME intake were evaluated utilizing 78 individual feeds representing 17 different forages, grains, protein meals and by-product feedstuffs. The predictive approaches evaluated were two each from National Research Council [National Research Council (NRC), Nutrient Requirements of Dairy Cattle, seventh revised ed. National Academy Press, Washington, DC, USA, 2001], University of California at Davis (UC Davis) and ADAS (Stratford, UK). Slopes and intercepts for the two ADAS approaches that utilized in vitro digestibility of organic matter and either measured gross energy (GE), or a prediction of GE from component assays, and one UC Davis approach, based upon in vitro gas production and some component assays, differed from both unity and zero, respectively, while this was not the case for the two NRC and one UC Davis approach. However, within these latter three approaches, the goodness of fit (r(2)) increased from the NRC approach utilizing lignin (0.61) to the NRC approach utilizing 48 h in vitro digestion of neutral detergent fibre (NDF:0.72) and to the UC Davis approach utilizing a 30 h in vitro digestion of NDF (0.84). The reason for the difference between the precision of the NRC procedures was the failure of assayed lignin values to accurately predict 48 h in vitro digestion of NDF. However, differences among the six predictive approaches in the number of supporting assays, and their costs, as well as that the NRC approach is actually three related equations requiring categorical description of feeds (making them unsuitable for mixed feeds) while the ADAS and UC Davis approaches are single equations, suggests that the procedure of choice will vary dependent Upon local conditions, specific objectives and the feedstuffs to be evaluated. In contrast to the evaluation of the procedures among feedstuffs, no procedure was able to consistently discriminate the ME values of individual feeds within feedstuffs determined in vivo, suggesting that the quest for an accurate and precise ME predictive approach among and within feeds, may remain to be identified. (C) 2004 Elsevier B.V. All rights reserved.

The effect of wilting and soaking Eupatorium adenophorum on its digestibility in vitro and voluntary intake by goats

An experiment was conducted to determine what effect simple treatments might have on the voluntary intake by goats in Nepal of Eupatorium adenophorum, an invasive weed that is usually only consumed by goats to a very limited extent. Samples of E. adenophorum were collected and either untreated, soaked for 2 h or wilted for 2 h before being oven dried (60 degrees C) and ground. Soaking and wilting had little effect on the chemical composition of E. adenophorum, but did increase (P=0.036) its in vitro organic matter degradability, by approximately 8%. The short-term intake rate (STIR) of treated and untreated E. adenophorum was then estimated with eight goats. Soaking time (from 2 to 24 h) was not related to STIR (r = -0.111, P=0.198), but the time E. adenophorum was left to wilt (from 2 to 48h), was positively related to STIR (r=0.521, P<0.001), with values of STIR (g dry matter/min kg goat liveweight(0.75)) being 0.405, 0.649,1.058, S.E.M. 0.088 for E. adenophorum, that had been wilted for 0, 24 and 48 h respectively (P<0.001). Liveweight change of goats and voluntary intake of E. adenophorum by goats was then estimated with 24 goats. E. adenophorum was fed either unwilted, or wilted for 24 or 48 h. It was fed as the sole forage or as a 3:1 mixture (dry matter basis) with Ficus cunia. There was a linear (P<0.001) and quadratic (P<0.01) increase in the intake of total forage and E. adenophorum with wilting time of E. adenophorum. Offering Ficus cunia increased total forage intake, but decreased E. adenophorum intake (P<0.05). After four weeks, there was virtually no change in goat liveweight and no significant difference between treatments. The results suggest that wilting E adenophorum for 24 h could increase its intake by goats, and thereby increase its usefulness, as a potential source of forage in the dry season of Nepal, when forage scarcity is a common constraint to livestock production. (C) 2007 Elsevier B.V. All rights reserved.

Dichrostachys cinerea and Acacia nilotica fruits as dry season feed supplements for goats in a semi-arid environment: Summary of a DFID funded project in Zimbabwe

Indehiscent fruits of six tree species, common in Matabeleland were examined in in vitro and in vivo trials. The results for two of them, Acacia nilotica and Dichrostachys cinerea are presented here. Acacia nilotica-contained more total phenolics than D. cinerea, but less nitrogen (N) and fibre (ADF and NDF). After 48 h incubation, in vitro OMD of both species was increased by PEG and NaOH or wood ash treatment, except when NaOH or wood ash were used in combination with PEG with D. cinerea fruits. DM intake, DMD were lowest and N-retention negative in goats fed A. nilotica as supplement. However when fed a supplement of D. cinerea, untreated or treated with PEG or NaOH, digestibility and N-retention were highest, and similar to a commercial goat meal, with the untreated fruit. In a trial in which milking does were supplemented with D. cinerea fruits, for 65 before and 65 days after kidding, kid birthweight and weaning weight were increased by supplementation. Deaths of twin-born kids were lowest in the supplemented but unmilked group. Supplementation with D. cinerea fruit resulted in improved goat performance. The only treatment applied of practical significance, wood ash, is currently being tested in an in vivo study. More research is required on detoxification of tannins, especially with A. nilotica. (c) 2005 Elsevier B.V. All rights reserved.

Limit-feeding a high-energy diet to meet energy requirements in the dry period alters plasma metabolite concentrations but does not affect intake or milk production in early lactation

Limit-feeding dry cows a high-energy diet may enable adequate energy intake to be sustained as parturition approaches, thus reducing the extent of negative energy balance after parturition. Our objective was to evaluate the effect of dry period feeding strategy on plasma concentrations of hormones and metabolites that reflect energy status. Multiparous Holstein cows (n = 18) were dried off 45 d before expected parturition, paired by expected calving date, parity, and previous lactation milk yield, and randomly assigned to 1 of 2 dry-period diets formulated to meet nutrient requirements at ad libitum or limited intakes. All cows were fed the same diet for ad libitum intake after parturition. Prepartum dry matter intake (DMI) for limit-fed cows was 9.4 kg/d vs. 13.7 kg/d for cows fed ad libitum. During the dry period, limit-fed cows consumed enough feed to meet calculated energy requirements, and ad libitum-fed cows were in positive calculated net energy for lactation (NEL) balance (0.02 vs. 6.37 Mcal/d, respectively). After parturition, milk yield, milk protein concentration, DMI, body condition score, and body weight were not affected by the prepartum treatments. Cows limit fed during the dry period had a less-negative calculated energy balance during wk 1 postpartum. Milk fat concentration and yield were greater for the ad libitum treatment during wk 1 but were lower in wk 2 and 3 postpartum. Plasma insulin and glucose concentrations decreased after calving. Plasma insulin concentration was greater in ad libitum-fed cows on d -2 relative to calving, but did not differ by dietary treatment at other times. Plasma glucose concentrations were lower before and after parturition for cows limit-fed during the dry period. Plasma nonesterified fatty acid concentrations peaked after parturition on d 1 and 4 for the limit-fed and ad libitum treatments, respectively, and were greater for limit-fed cows on d -18, -9, -5, and -2. Plasma tumor necrosis factor-alpha concentrations did not differ by treatment in either the pre- or postpartum period, but tended to decrease after parturition. Apart from a reduction in body energy loss in the first week after calving, limit feeding a higher NEL diet during the dry period had little effect on intake and milk production during the first month of lactation.

Effect of feed restriction and supplemental dietary fat on gut peptide and hypothalamic neuropeptide mRNA concentrations in growing wethers

The objectives of the present study were 1) to evaluate the effects of supplemental fat and ME intake on plasma concentrations of glucagon-like peptide-1 (GLP-1), cholecystokinin (CCK), glucose-dependent insulinotropic polypeptide, ghrelin, and oxyntomodulin; and 2) to determine the association of these peptides with DMI and the hypothalamic concentration of mRNA for the following neuropeptides: neuropeptide Y (NPY), agouti-related peptide (AgRP), and proopiomelanocortin (POMC). In a completely randomized block design with a 2 x 2 factorial arrangement of treatments, 32 pens with 2 wethers each were restricted-fed (2.45 Mcal/lamb per day) or offered diets ad libitum (n = 16) with or without 6% supplemental fat (n = 16) for a period of 30 d. Dry matter intake was measured daily. On d 8, 15, 22, and 29, BW was measured before feeding, and 6 h after feeding, blood samples were collected for plasma measurement of insulin, GLP-1, CCK, ghrelin, glucose-dependent insulinotropic polypeptide, oxyntomodulin, glucose, and NEFA concentrations. On d 29, blood was collected 30 min before feeding for the same hormone and metabolite analyses. At the end of the experiment, wethers were slaughtered and the hypothalami were collected to measure concentrations of NPY, AgRP, and POMC mRNA. Offering feed ad libitum (resulting in greater ME intake) increased plasma insulin and NEFA concentrations (P = 0.02 and 0.02, respectively) and decreased hypothalamic mRNA expression of NPY and AgRP (P = 0.07 and 0.02, respectively) compared with the restricted-fed wethers. There was a trend for the addition of dietary fat to decrease DMI (P = 0.12). Addition of dietary fat decreased insulin and glucose concentrations (P < 0.05 and 0.01, respectively) and tended to increase hypothalamic mRNA concentrations for NPY and AgRP (P = 0.07 and 0.11, respectively). Plasma GLP-1 and CCK concentrations increased in wethers offered feed ad libitum compared with restricted-fed wethers, but the response was greater when wethers were offered feed ad libitum and had supplemental fat in the diet (fat x intake interaction, P = 0.04). The prefeeding plasma ghrelin concentration was greater in restricted-fed wethers compared with those offered feed ad libitum, but the concentrations were similar 6 h after feeding (intake x time interaction, P < 0.01). Supplemental dietary fat did not affect (P = 0.22) plasma ghrelin concentration. We conclude that insulin, ghrelin, CCK, and GLP-1 may regulate DMI in sheep by regulating the hypothalamic gene expression of NPY, AgRP, and POMC.

Methane emissions from cattle: estimates from short-term measurements using a Green Feed system compared with measurements obtained using respiration chambers or sulphur hexafluoride tracer

The Green Feed (GF) system (C-Lock Inc., Rapid City, USA) is used to estimate total daily methane emissions of individual cattle using short-term measurements obtained over several days. Our objective was to compare measurements of methane emission by growing cattle obtained using the GF system with measurements using respiration chambers (RC)or sulphur hexafluoride tracer (SF6). It was hypothesised that estimates of methane emission for individual animals and treatments would be similar for GF compared to RC or SF6 techniques. In experiment 1, maize or grass silage-based diets were fed to four growing Holstein heifers, whilst for experiment 2, four different heifers were fed four haylage treatments. Both experiments were a 4 × 4 Latin square design with 33 day periods. Green Feed measurements of methane emission were obtained over 7 days (days 22–28) and com-pared to subsequent RC measurements over 4 days (days 29–33). For experiment 3, 12growing heifers rotationally grazed three swards for 26 days, with simultaneous GF and SF6 measurements over two 4 day measurement periods (days 15–19 and days 22–26).Overall methane emissions (g/day and g/kg dry matter intake [DMI]) measured using GF in experiments 1 (198 and 26.6, respectively) and 2 (208 and 27.8, respectively) were similar to averages obtained using RC (218 and 28.3, respectively for experiment 1; and 209 and 27.7, respectively, for experiment 2); but there was poor concordance between the two methods (0.1043 for experiments 1 and 2 combined). Overall, methane emissions measured using SF6 were higher (P<0.001) than GF during grazing (186 vs. 164 g/day), but there was significant (P<0.01) concordance between the two methods (0.6017). There were fewer methane measurements by GF under grazing conditions in experiment 3 (1.60/day) com-pared to indoor measurements in experiments 1 (2.11/day) and 2 (2.34/day). Significant treatment effects on methane emission measured using RC and SF6 were not evident for GF measurements, and the ranking for treatments and individual animals differed using the GF system. We conclude that under our conditions of use the GF system was unable to detectsignificant treatment and individual animal differences in methane emissions that were identified using both RC and SF6techniques, in part due to limited numbers and timing ofmeasurements obtained. Our data suggest that successful use of the GF system is reliant on the number and timing of measurements obtained relative to diurnal patterns of methane emission.

Toxicidade residual de alguns agrotóxicos recomendado na agricultura sobre Neoseiulus californicus (McGregor) (Acari: Phytoseiidae)

O objetivo do trabalho foi avaliar a toxicidade residual de alguns agrotóxicos utilizados em citros sobre Neoseiulus californicus (McGregor) em condições de laboratório. O método de bioensaio adotado foi o de contato residual. Folhas de citros da variedade Pêra, acondicionadas em arenas, foram pulverizadas em torre de Potter. A toxicidade residual dos produtos foi avaliada duas horas e 1; 3; 5; 7; 10; 14 e 21 dias após a aplicação. em cada arena, foram transferidas dez fêmeas adultas de N. californicus, juntamente com uma quantidade suficiente de Tetranychus urticae, como fonte de alimento. As avaliações de mortalidade foram realizadas 72 horas após a transferência dos ácaros para as arenas. Os agrotóxicos acrinathrin, deltamethrin, dinocap, enxofre, fenpropathrin, óxido de fenbutatin e propargite não causaram mortalidades significativas em adultos de N. californicus. Foram registradas mortalidades de 29,8; 24,0 e 34,1% para ácaros N. californicus expostos a resíduos de duas horas de idade de abamectim, azocyclotin e cyhexatin, respectivamente. Dicofol, pyridaben e chlorfenapyr causaram 100% de mortalidade aos ácaros predadores expostos aos resíduos tóxicos dos acaricidas, com duas horas de idade. Abamectin provocou mortalidade significativa por um período inferior a um dia. Resíduos dos acaricidas azocyclotin, cyhexatin, dicofol, pyridaben e chlorfenapyr provocaram mortalidades significativas por períodos de 1; 1; 10; 10 e 21dias, respectivamente. Os resultados obtidos no presente experimento servem de subsídio para a escolha adequada dos agrotóxicos a serem utilizados em pomares de citros nos quais N. californicus esteja presente ou naqueles em que o predador venha a ser liberado. Esses resultados também servem para a escolha do momento mais favorável para a liberação dos ácaros predadores dessa espécie no campo, após a aplicação de agrotóxicos nos pomares. Estudos conduzidos em condições de campo ainda são necessários para se compreender melhor o efeito desses agrotóxicos sobre o ácaro predador.

Influence of chlorine added to drinking water during the preslaughter feed withdrawal on microbiology and morphology of the broiler gastrointestinal tract

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Sodium levels for Japanese quail at initial phases

The aim of this research was to determine the nutritional requirements of sodium for Japanese quail (Coturnix coturnix Japonica) during the periods of 1 to 21 d and 22 to 40 d of age, as well as to evaluate the residual effect on egg production and densitometry bone traits from 41 to 63 d. Two experiments were developed. Experiment 1: 360 Japanese quail were used, from 1 to 21 d of age. Treatments consisted of 5 sodium levels (0.06, 0.12, 0.18, 0.24, and 0.30%). Experiment 2: 240 Japanese quail were used, from 22 to 40 d. Treatments consisted of 5 sodium levels (0.04, 0.12, 0.20, 0.28, and 0.36%). In both experiments, weight gain, final weight, and feed conversion presented a quadratic trend, whereas water intake presented a linear trend. Treatments did not affect the densitometry of bone traits, although they presented a quadratic influence on tibia ash, calcium, and calcium: phosphorus ratio. Therefore, the nutritional requirement of sodium for Japanese quail from 1 to 21 d and from 22 to 40 d is 0.222% and 0.253%, respectively.

Intake and performance of confined crossbred heifers fed different lipid sources

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Performance, carcass characteristics and gain cost of feedlot cattle fed a high level of concentrate and different feed additives

The objective of this study was to evaluate the effects of feeding cattle with isoprotein and isoenergetic diets, with and without the addition of polyclonal antibody preparation (PAP), yeasts (YST) or monensin sodium (MON) on performance, carcass characteristics and gain cost in feedlot. Ninety-five 20-month old bullocks (323.3±21.8 kg) were distributed in 25 pens. The completely randomized experimental design had a 2 × 2 + 1 factorial arrangement and the treatments were replicated 5 times. There was no effect of MON for DMI throughout the feedlot period; however, MON reduced the dry matter intake (DMI) in g/kg of BW in the first 28 days when compared with the other treatments. The gain cost decreased with MON addition in relation to the other treatments. Inclusion of YST decreased average daily gain (ADG), final body weight, hot carcass weight, carcass weight, gain to feed ratio and DMI in g/kg body weight, worsening feed conversion and increasing the gain cost in the feeding periods. Inclusion of PAP increased ADG and decreased the gain cost, besides improving feed conversion. For MON and PAP, a difference was found for kidney-pelvic fat and kidney-pelvic fat per 100 kg of hot carcass weight. For MON and YST, there was a difference in ADG, feed conversion, gain cost and carcass yield and kidney-pelvic fat per 100 kg of hot carcass. Treatment YST worsened performance in relation to the non-supplemented treatments. Feeding PAP to animals did not influence performance and carcass characteristics of bullocks in feedlot negatively. Thus, PAP shows potential to substitute MON in cattle feeding using isoprotein and isoenergetic diets.

Use of high moisture corn silage replacing dry corn on intake, apparent digestibility, production and composition of milk of dairy goats

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)