in vitro models to evaluate the capacity of different sequestering agents to adsorb aflatoxins

Eight potential aflatoxin-sequestering agents (SAs) were tested for their ability to adsorb aflatoxin B1 (AfB1) and aflatoxin G1 (AfG1) in vitro. They belong to main SA classes: silicate minerals (calcium, magnesium and sodium bentonites, kaolinite, zeolite and clinoptinolite), activated carbon and yeast cell wall-derived. The AfB1 and AfG1 used in present work were extracted from a contaminated corn meal (82.21 mg/kg of AfB1 and 97.20 mg/kg of AfG11). Three single-concentration adsorption tests, consisting of a simply-water (W), a gastrointestinal simulating monogastric model (MM) and a ruminant model (RM), were used. The methods differed for dilution media, incubation steps and pH condition in which they were conducted. In particular, one step (2h at 39°C) at pH 7 for W; two steps (4h at 39°C) at pH 2 and 7 for MM; and a pre-incubation in rumen fluid (pH 7 for 2h at 39°C) + two steps (4h at 39°C) at pH 2 and 7 for RM, characterized each method. The AfB1:SA ratio (g/g) and dilution factor (ng of incubated AfB1:mL of volume) were chosen (1:500,000 and 4.1, respectively) to reflect field conditions. The AfB1 and AfG1 recovered in controls were 92.3% and 104.9% in W and 89.5% and 101.5% in MM; while in RM were 65.2% and 81.9%; respectively. This supported the idea of intrinsic rumen fluid factors could be involved in sequestering of aflatoxins. In the present study, three SAs (activated carbon, Mg bentonite and Na bentonite) were very efficient to sequester the available AfB1, with a sequestering activity of over 99.0% with each method. The Ca bentonite and clinoptinolite were able to bind available AfB1 in MM and RM methods, while they appeared inefficient (available AfB1 sequestered less than 80%) when W was used. The adsorption ability of zeolite was confirmed only with the W method. Ineffective or limited sequestering activity were obtained with kaolinite and yeast cell wall-derived products with each method. The AfB1 and AfG1 sequestering efficiencies observed in the present work resulted very similar showing strong and positive correlation (P<0.001) within methods (r=0.79, r=0.96 and r=0.99, respectively for W, MM and RM methods). The two simulated gastrointestinal methods (MM and RM, respectively) gave similar results and could be considered useful for in vitro pre-screening of potential sequestering agents. However, the major practical and analytical implications related to rumen fluid method suggested that MM method should be used

A comparison of methods to quantify prolamin contents in cereals

Hydrophobic prolamins are endosperm storage proteins accounting for about 40% of the total protein in most cereals seeds. Despite the absence of a reference method, several procedures have been periodically published to quantify prolamins in cereals. The aim of this study was to compare a conventional fractionation assay (LND) vs three other methods: one based on sequential extractions (HAM) and two rapid turbidimetric procedures (L&H and DRO). Prolamins were extracted in duplicate on barley, corn and wheat samples. For the turbidimetric prolamin evaluation in barley and wheat, a universally available purified gliadin, as alternative to purified zein, was also tested as standard reference material (SRM). The extraction prolamin values were different among grain types (P0.05). LND agreed sufficiently well both with HAM and with L&H methods (R2=0.664 and R2=0.703, respectively, P0.05), whereas a higher prolamin quantification was obtained using HAM (P<0.05). Overall, DRO did not provide similar comparison and performance parameters with respect to other method comparisons. The effect of changing purified zein with purified gliadin was noteworthy only for L&H, both for wheat and barley samples (P<0.01). Considering the increasing attention of animal nutritionists on prolamins, our results could get useful information for routine laboratories analysis

Technical note: Evaluation of a novel enzymatic method to predict in situ undigested neutral detergent fiber of forages and nonforage fibrous feeds.

ABSTRACT The purpose of this study was to optimize the conditions of a previously proposed enzymatic method used to estimate in situ undigested neutral detergent fiber (uNDF). We used a multi-step enzymatic approach, in which samples were first solubilized in NaOH solutions as a preincubation (PreInc) phase. After rinsing, samples were incubated (24 h at 39°C) in a buffered solution (pH 6) containing hemicellulase, cellulase, and Viscozyme L enzymes (Sigma-Aldrich s.r.l., Milan, Italy), followed by incubation (24 h at 39°C) in a buffered solution (pH 5) containing xylanase. Two sets of experiments were performed: a calibration trial (that tested different PreInc conditions on 9 selected forages) and a validation trial (that verified the results by testing multiple samples of 6 different forage types and a group of fibrous by-products). In the calibration trial, samples (300 mg in Ankom F57 filter bags; Ankom Technology Corp., Fairport, NY) were preincubated at 39°C in a 0.1 M NaOH solution for 90, 180, or 240 min, or in 0.2, 0.5, 1.0, or 2.0 M NaOH solution for 90 min. The results indicated that the best PreInc method, in terms of intra-laboratory repeatability and estimation of reference in situ values, was 90 min in a 0.2 M NaOH solution. Thus, we used this PreInc condition to determine enzymatic uNDF of 257 samples in the validation trial. Although the selected method generally had good accuracy in predicting in situ uNDF, inconsistencies were noted for certain forage types. Overall, when enzymatic uNDF was used to predict the in situ uNDF of all samples, the regression was satisfactory (intercept = 7.098, slope = 0.920, R2 = 0.73). The regression models developed for alfalfa hays, corn silages, and small grain silages had also acceptable regression performances and mean square error of prediction (MSEP) values, and the main sources of MSEP variation were error due to incomplete (co)variation and random error. Even when R2 values were >0.70, the MSEP value of the regression model for grass hays was 149.55, and that for nonforage fibrous feeds was 155.16. Although enzymatic uNDF partially overestimated the in situ uNDF, particularly in grass silages, the proposed procedure seems to be promising for accurately predicting in situ uNDF, because it generally had good repeatability and provided satisfactory estimates of in situ uNDF

Effect of extrusion, espansion and toasting on the nutritional value of peas, faba beans and lupins

An assessment was made of the effect that different treatments (toasting, expansion, extrusion) have on the nutritionalvalue of protein plants (pea, faba bean, lupin). In a randomized block design, feeds were screened for enzymaticdigestibility of starch and protein, N solubility and in vitro protein degradability. Expansion and extrusion cause increasedstarch enzymatic degradability while toasting produced virtually no effects. In peas this value increased from 11.80% inmeal to 39.70% in the extruded product; 85.37% is the percentage for the expanded product, while 10.90% is the starchdigestibility value for toasted peas. In faba beans the extrusion process increased starch digestibility from 11.39% to85.05%, while in extruded lupins a complete starch hydrolysis was obtained, while in the meal the polysaccharide digestionwas 54.48%.The expansion and extrusion processes significantly decreased rumen degradability during the first 8 hours of incubation.Toasted peas had lower degradability if compared with controls but not with the other treatments. The onlypotentially alternative source to soybean is the extruded faba bean. In spite of its lower protein content, this feed ischaracterized by a considerably lower in vitro protein degradability than soybean. This implies that the digestible foodprotein content is comparable (124.90 g/kg DM) to that of soybean (109.78 g/kg DM) and definitely higher than thatof all other protein plants

Spatially-smooth regionalization of flow duration curves in non-pristine basins

The flow duration curve (FDC) is a fundamental signature of the hydrological cycle to support water management strategies. Despite many studies on this topic, its estimation in ungauged basins is still a relevant issue as the FDC is controlled by different types of processes at different time-space scales, thus resulting quite sensitive to the specific case study. In this work, a regional spatially-smooth procedure to evaluate the annual FDC in ungauged basins is proposed, based on the estimation of the L-moments (mean, L-CV and L-skewness) through regression models valid for the whole case study area. In this approach, homogeneous regions are no longer required and the L-moments are allowed to continuously vary along the river network, thus providing a final FDC smoothly evolving for different locations on the river. Regressions are based on a set of topographic, climatic, land use and vegetation descriptors at the basin scale. Moreover, the model ensures that the mean annual runoff is preserved at the river confluences, i.e. the sum of annual flows of the upstream reaches is equal to the predicted annual downstream flow. The proposed model is adapted to incorporate different “sub-models” to account for local information within the regional framework, where man-induced alterations are known, as common in non-pristine catchments. In particular, we propose a module to consider the impact of existing/designed water withdrawals on the L-moments of the FDC. The procedure has been applied to a dataset of daily observation of about 120 gauged basins on the upper Po river basin in North-Western Italy

Short communication: In vitro rumen gas production and starch degradation of starch-based feeds depend on mean particle size

Our objective was to model the effect of mean particle size (mPS) on in vitro rumen starch degradation (IVSD) and the kinetics of gas production for different starch-based feeds. For each feed, 2 batches of the same grains were separately processed through 2 different mills (cutter or rotor speed mills), with or without different screens to achieve a wide range of mPS (0.32 to 3.31 mm for corn meals; 0.19 to 2.81 mm for barley meals; 0.16 to 2.13 mm for wheat meals; 0.28 to 2.32 mm for oat meals; 0.21 to 2.36 mm for rye meals; 0.40 to 1.79 for sorghum meals; 0.26 to 4.71 mm for pea meals; and 0.25 to 4.53 mm for faba meals). The IVSD data and gas production kinetics, obtained by fitting to a single-pool exponential model, were analyzed using a completely randomized design, in which the main tested effect was mPS (n = 6 for all tested meals, except n = 7 for corn meals and n = 5 for sorghum meals). Rumen inocula were collected from 2 fistulated Holstein dairy cows that were fed a total mixed ration consisting of 16.2% crude protein, 28.5% starch, and 35.0% neutral detergent fiber on a dry matter basis. The IVSD, evaluated after 7 h of rumen incubation, decreased linearly with increasing mPS for corn, barley, wheat, rye, pea, and faba meals, and decreased quadratically with increasing mPS for the other meals. The y-axis intercept for 7-h IVSD was below 90% starch for corn, barley, and rye feeds and greater than 90% for the other tested feeds. The mPS adjustment factors for the rate of rumen starch degradation varied widely among the different tested feeds. We found a linear decrease in starch degradation with increasing mPS for barley, wheat, rye, and pea meals, whereas we noted a quadratic decrease in starch degradation for the other tested meals. Further, we observed a linear decrease in the rate of gas production with increasing mPS in each tested feed, except for pea meal, which had a quadratic relationship. For each 1 mm increase in mPS, the gas production was adjusted by -0.009 h-1 for corn, -0.011 h-1 for barley, -0.008 h-1 for wheat, and -0.006 h-1 for faba, whereas numerically greater adjustments were needed for oat (-0.022 h-1), rye (-0.017 h-1), and sorghum (-0.014 h-1). These mPS adjustment factors could be used to modify the starch-based feed energy values as a function of mean particle size, although in vivo validation is required

repeatability and reproducibility of the cornell net carbohydrate and protein system analytical determinations

The increasing use in Italy of the Cornell Net Carbohydrate and Protein System (CNCPS) led researchers of five Italianuniversities to carry out a collaborative study to evaluate the precision of the CNCPS chemical analysis and derivate fractions.Each laboratory conducted in duplicate the chemical analyses according to the Weende (dry matter; crude protein;ether extract; crude fibre; ash), Van Soest (neutral and acid detergent fibre, NDF and ADF; acid detergent lignin; ADL)and CNCPS (soluble proteins, SP; non-protein nitrogen, NPN; neutral and acid detergent insoluble protein, NDIP andADIP; starch, ST) schemes on the same five feeds (barley meal, wheat straw, maize silage, dried lucerne and fieldbeans). Anomalous analytical data were identified and corrected by the “box-plot” graphic tool before the calculation ofthe CNCPS protein (B1, B2 and B3) and carbohydrate (A, B2 and C) fractions. Finally, repeatability (chemical analysis) andreproducibility (chemical analysis and fractions) were calculated and expressed as relative values (repeatability andreproducibility standard deviation as percentage of the corresponding mean, RSDr and RSDR, respectively). Chemicalanalyses of the Weende scheme, together with NDF, ADF and ST analyses, have satisfactory repeatability (0.3-6.2%) andreproducibility (0.3-11.2%) values. On the contrary the ADL, NPN, NDIP and ADIP analyses showed high variability, bothwithin and between laboratories (RSDr and RSDR between 20 and 45%). The SP analysis had an intermediate value ofprecision (RSDr=10.6%; RSDR=16.4%).Finally, since different combinations of several chemical analyses with scarce (ADL, NPN, NDIP, ADIP, SP) or average precision(e.g. NDF and starch) are used to calculate CNCPS fractions (excluding B2 protein fraction), also the reproducibilitiesof these fractions are poor and range from 10 to 20%

Short communication: The effect of an exogenous enzyme with amylolytic activity on gas production and in vitro rumen starch degradability of small and large particles of corn or barley meals

The objective of this study was to evaluate the effect of exogenous amylase supplementation on gas production and on in vitro rumen starch degradability (IVSD) of different sized particles of corn and barley meals (Cm and Bm, respectively). An aqueous liquid amylase formulation from Bacillus licheniformis was tested at 3 enzyme doses (EnzD; 0, 300 and 1,500 kilo novo units/kg of dry matter) on small (<750 µm) and large (≥750 µm) particle size (PS) of Cm and Bm. Data were analyzed according to a randomized complete block design with a factorial arrangement of treatments; the main tested effects were PS, EnzD, and their interaction. Fermentation run entered in the model as random effect. The mixed rumen fluid was collected from 2 rumen-fistulated Holstein dry dairy cows fed at maintenance (forage:concentrate ratio of 80:20; 12% crude protein; 55% amylase-treated neutral detergent fiber). Small particles of both Cm and Bm had a greater rate of fermentation and shorter lag time than large particles. The rate of starch degradation was greater for small than for large particles of Bm, being 0.187 and 0.125 1/h, respectively. Conversely, the rate of starch degradation of Cm averaged 0.063 1/h and was similar among treatments. Enzyme supplementation tended to reduce lag time and to increase rate of fermentation for both PS of Cm and Bm, with a more pronounced effect for small PS. A limited EnzD effect was measured for IVSD data and rate of starch degradation; PS influenced fermentation parameters and the magnitude of starch degradation more than EnzD. Supplementation with exogenous amylase influenced the rumen fermentation pattern of small and large PS of Cm and Bm, even if the effect of the enzyme supplementation differed according to the PS of cereal meals

Pea (Pisum sativum) and faba bean (Vicia faba L.) seeds as protein sources in growing-finishing heavy pig diets: effect on growth performance, carcass characteristics and on fresh and seasoned Parma ham quality

The effect of pea and faba bean inclusion in growing-finishing heavy pig diets was evaluated. The following iso-lysinic and iso-energetic diets offered to the pigs in three phases (40-80; 80-120; 120-160 kg) were compared: CTR, control diet with soybean meal (SBM) as protein source; RP, CTR diet where pea replaced SBM; RF, CTR diet where faba bean replaced SBM. 126 animals were randomly distributed in 3 homogeneous groups with 42 animals each (7 pens with 6 animals each per treatment). The RP and RF diets did not negatively affect the carcass characteristics both of the pigs slaughtered at the conventional weight (127.5 kg) and heavy pigs (158.5 kg). The pigs fed the RP and RF diets ate similarly to the pigs fed the CTR overall the trial but RF pigs grew better than CTR animals. The subcutaneous fat of the fresh hams destined for Parma ham production and obtained from pigs fed RP diet had a higher omega 3 fatty acid percentage. Moreover, the RP and RF diets resulted in fat with better omega 3/omega 6 ratio compared with CTR. All the fat samples had iodine numbers within the limit value (70) reported by the Production Disciplinary of Parma ham. No treatment effect was found on the analytical and sensorial characteristics of the Parma hams, except for the aged taste which was more intense in the hams obtained from pigs fed the RF diet. These results indicate that pea and faba bean may be used as an alternative to imported SBM

A survey of dairy cattle management, crop planning, and forages cost of production in Northern Italy

A survey regarding crop enterprise management, forages cost of production, dairy cattle management including reproductive management, housing, heat abatement, body condition scoring, nutrition, grouping strategies, and income over feed cost performance, was carried out from December 2016 to January 2018 on 50 dairy farms by the Department of Animal Science, Food and Nutrition of Università Cattolica del Sacro Cuore (Piacenza, Italy). A total of 41 herds (82%) completed the survey. Average herd size was 327 ± 162 lactating cows with the average land size of 160 ± 94 ha per farm. Herds were located in the provinces of Cremona (17), Brescia (8), Mantova (7), Piacenza (5), Cuneo (4), Bergamo (3), Lodi (3), Torino (2), and Venezia (1). These farms sold 32.8 ± 2.01 kg of milk/day per cow, had an annual culling rate of 34.0 ± 4.00%, a calving interval of 14.16 ± 0.58 months., and a 21-days pregnancy rate of 17.05 ± 2.58%. Implementing effective management strategies to contrast the damage caused by Ostrinia nubilalis, Diabrotica spp. and Myocastor coypus were identified as the main crop enterprise challenges. Main forages cultivated were alfalfa and corn silage second seeding with a total cost of production of (€/ha) 1968 ± 362 and 2,581 ± 221, with an average yield of 9.61 ± 1.24 and 17.22 ± 2.46 ton of DM per hectare, respectively. Results of this study can provide useful benchmark or reference for dairy management practices, crops and dairy performances, forages production costs on very well-managed North Italian dairy farms at the present time.Highlights benchmarks for dairy farms management practices, economic and reproductive performance cost of production of forages in northern Ital