Effects of length of ensiling and maturity group on chemical composition and in vitro ruminal degradability of whole‐crop maize

Nine hybrids (three maturity groups, dry matter 343 ± 5.6 g/kg) of whole‐crop maize were ensiled in eight replicates in laboratory‐scale silos. Each hybrid was sampled at harvest and after 30, 60, 90 and 120 days (d) of ensiling. Samples were analysed for chemical composition (proximate constituents, fermentation products and pH), starch, non‐protein N (NPN) and NH₃‐N. Each sample and its neutral detergent fibre (NDF) fraction were incubated in the Hohenheim gas test system. In vitro gas production was measured after 0, 2, 4, 8, 12, 16, 24, 36, 48, 72 and 96 hr of incubation. Gas production of the neutral detergent soluble (NDS) fraction (mainly starch) was calculated using a curve subtraction method. Gas production dynamics over time were estimated using a nonlinear regression equation; afterwards, a two‐factorial analysis of variance (storage length, maturity group and their interaction) using the general linear models procedure was conducted. After 30 d, all silages were well fermented. Most fermentation products and proximate constituents only changed until 30 or maximum 60 d of ensiling. Only few changes in in vitro nutrient degradability were detected after the first 30 d or as influenced by maturity group. Ensiling per se increased the ruminal degradability of the NDS, but there was no further increase caused by a prolonged duration of storage. However, extensive changes in crude protein fractions occurred with a linear increase in NPN and NH₃‐N compounds from 0 to 120 d of storage, indicating continual protein and amino acid degradation.     

The present and future of withdrawal period calculations for milk in the European Union: dealing with data below the limit of quantification

The assessment of withdrawal periods for milk is affected by the occurrence of data below the lower analytical quantification limit (BLQ data) and the resulting uncertainty. The current regulatory approach for dealing with BLQ residues is simple and easy: BLQ data (and missing data) are arbitrarily reassigned a value of one‐half the LOQ before any calculation on the data with one of the three currently applicable methods. Here, we reconsider the determination of the withdrawal period of milk with data below the limit of quantification. Theoretical background on analytical limits and pharmacometric considerations will be established. Then, we analyze the uncertainty problems caused by the current approach and propose a calculation solution (maximum‐likelihood estimation handling left‐censored data) included in nonlinear mixed‐effects modeling. Finally, we illustrate this issue using a case example.     

Intestinal microbiota of broilers submitted to feeding restriction and its relationship to hepatic metabolism and fat mass: Fast‐growing strain

The present study was conducted to verify how feed restriction affects gut microbiota and gene hepatic expression in broiler chickens and how these variables are related to body weight gain. For the experiment, 21‐d‐old Cobb500^TM birds were distributed in a completely randomized experimental design with three treatments: T1. Control (ad libitum—3.176 Mcal/kg ME—metabolizable energy—and 19% CP—crude protein); T2. Energetic restriction (2.224 Mcal/kg ME and 19% CP) from 22 to 42 days with consumption equivalent to control; T3. Quantitative restriction (70% restriction, i.e., restricted broilers ingested only 30% of the quantity consumed by the control group—3.176 Mcal/kg ME and 19% CP) for 7 days, followed by refeeding ad libitum from 28 to 42 days. Ileum and caecum microbiota collections were made at 21, 28 and 42 days of age. Hepatic tissue was collected at 28 and 42 days old for relative gene expression analyses. At 43‐d‐old, body composition was quantified by DXA (Dual‐energy X‐ray Absorptiometry). Both feed restriction programmes decreased Lactobacillus and increased Enterococcus and Enterobacteriaceae counts. No differences were found in the refeeding period. Energetic restriction induced the expression of CPT1‐A (Carnitine palmitoyltransferase 1A) gene, and decreased body fat mass. Quantitative feed restriction increased lipogenic and decreased lipolytic gene expression. In the refeeding period, CPT1‐A gene expression was induced, without changing the broilers body composition. Positive associations were found between BWG (Body Weight Gain) and Lactobacillus and Clostridium cluster IV groups, and negatively associations with Enterobacteriaceae and Enterococcus bacterial groups. In conclusion, differences found in microbiota were similar between the two feed restriction programmes, however, hepatic gene expression differences were only found in quantitative restriction. Higher counts of Lactobacillus and Clostridium cluster IV groups in ileum are likely to be related to better broiler performance and low expression of lipogenic genes.     

Effects of Annealing and Concentration of Calcium Salts on Thermal and Rheological Properties of Maize Starch During an Ecological Nixtamalization Process

The objective of the present work was to study the effect of annealing and concentration of Ca(OH)₂ (lime) and calcium salts on the thermal and rheological properties of maize starch during an ecological nixtamalization process. Thermal and rheological properties of maize starch changed during the ecological nixtamalization process because of three main causes: the annealing phenomenon, type of calcium salt, and calcium salt concentration. In all treatments thermal properties (T_o, T_p, and T_f) of nixtamal starch increased owing to the annealing process, whereas the type of salt or lime increased thermal properties and decreased pasting properties in this order: CaCl₂ > CaSO₄ > Ca(OH)₂ ≈ CaCO₃. This behavior was because of the dissociation of each salt or lime in water. Anions (OH⁻) can penetrate much more easily into the starch granule and start the gelatinization process by rupturing hydrogen bonds. Additionally, amylose‐lipid complexes were formed during the nixtamalization processes, as indicated by an increasing peak at 4.5 Å in X‐ray diffraction patterns.     

Staling of Bread: Role of Amylose and Amylopectin and Influence of Starch‐Degrading Enzymes

The present investigation aims at understanding the mechanism of bread firming during staling. Changes in the starch fraction due to the addition of amylases and their influence on the texture of bread crumb were studied during aging and after rebaking of stale bread. Pan bread was prepared by a conventional baking procedure. The influence of three different starch‐degrading enzymes, a conventional α‐amylase, a maltogenic α‐amylase, and a β‐amylase were investigated. The mechanical properties of bread were followed by uniaxial compression measurements. The microstructure was investigated by light microscopy, and starch transformations were assessed by differential scanning calorimetry (DSC) and wide‐angle X‐ray powder diffraction. Firming of bread crumb and crystallization of starch are not necessarily in agreement in systems with added amylases. Reorganization of both starch fractions, amylopectin and amylose, and the increase of starch network rigidity due to increase of polymer order are important during aging. Starch‐degrading enzymes act by decreasing the structural strength of the starch phase; for instance, by preventing the recrystallization of amylopectin or by reducing the connectivity between crystalline starch phases. On the other hand, starch‐degrading enzymes may also promote the formation of a partly crystalline amylose network and, by this, contribute to a kinetic stabilization of the starch network. Based on the results, a model for bread staling is proposed, taking into account the biphasic nature of starch and the changes in both the amylose and amylopectin fraction.     

Rice Milling Quality,Grain Dimensions,and Starch Branching as Affected by High Night Temperatures

Important rice grain quality characteristics such as percentage of chalky rice kernels are affected by both high and low night temperatures and by different day and day/night temperature combinations. High nighttime temperatures have also been suspected of reducing rice milling quality including head rice yields. Experiments to confirm or refute this have not been reported. A controlled climate experiment was conducted. Conditions in the chambers were identical except between 2400 and 0500 hours (midnight and 5 am). For those times, two temperature treatments were imposed: 1) 18°C (low temperature treatment) and 2) 24°C (high temperature treatment). Two cultivars were tested: LaGrue and Cypress. The high temperature treatment reduced head rice yields compared with the low temperature treatment. Grain widths were reduced for the high temperature treatment compared with the low temperature treatment. There was no effect of temperature on grain length or thickness. Amylopectin chain lengths 13–24 were increased by the high temperature treatment by ≈1%. Future research will focus on determining whether genetic variability exists among cultivars in their head rice yield response to high temperatures. After identifying a source of resistance to high temperature effects, this characteristic can be incorporated into rice cultivars. In addition, ways to reduce this effect, including biotechnological remedies, have the potential for increasing rice yield and quality.     

Impact of effective microorganisms and other biofertilizers on soil microbial characteristics,organic‐matter decomposition,and plant growth

Incubation and pot experiments were conducted to investigate the impact of commercially distributed biofertilizers (effective microorganisms [EM], BIOSTIMULATOR, BACTOFIL‐A, and BACTOFIL‐B) on soil microbial‐biomass content and activity, net N mineralization in soil, and growth of Lolium perenne. According to the manufacturers, the products tested are based on microbial inoculants or organic growth stimulants, and are supposed to influence soil microbial properties and improve soil conditions, organic‐matter decomposition, and plant growth. In the incubation experiment (40 d, 20.6°C, 50% maximum water‐holding capacity), EM was repeatedly applied to soil together with different organic amendments (nonamended, chopped straw, and lupine seed meal). Under the experimental conditions of this study, no or only marginal effects of EM on organic C, total N, and mineral N in soil could be observed. In soil treatments without any organic amendment, EM suspension slightly enhanced microbial activity measured as soil CO₂ evolution. In soil with easily degradable plant residues (lupine seed meal), EM suspension had a suppressive effect on microbial biomass. However, comparisons with sterilized EM and molasses as the main additive in EM suspension showed that any effect of EM could be explained as a pure substrate effect without the influence of added living organisms. In the pot experiment with Lolium perenne (air‐conditioned greenhouse cabin, 87 d, 16.8°C, 130 klxh d^–1 light quantity), the products EM, BIOSTIMULATOR, BACTOFIL‐A, and BACTOFIL‐B were tested in soil with growing plants. The products were repeatedly applied for a period of 42 d. Within this study, no effects of the different biofertilizers on mineral N in soil were detectable. There were clear suppressive effects of all tested biofertilizers on microbial‐biomass content and activity. Comparisons with sterilized suspensions showed that the effects were not due to living microorganisms in the suspensions, but could be traced back to substrate‐induced processes.