High-grain diets supplemented with phytogenic compounds or autolyzed yeast modulate ruminal bacterial community and fermentation in dry cows

The feeding of concentrate-rich diets may lead to microbial imbalances and dysfermentation in the rumen. The main objective of this study was to determine the effects of supplementing phytogenic compounds (PHY) or autolyzed yeast (AY) on rumen fermentation and microbial abundance in cows intermittently fed concentrate-rich diets. The experiment was carried out as an incomplete 3 × 4 Latin square design, with 8 nonlactating rumen-fistulated Holstein-Friesian cows. The cows were randomly assigned to a concentrate diet that was either not supplemented (CON), or supplemented with PHY or AY. Each of the 4 consecutive experimental periods was composed of a 1-wk roughage-only diet (RD), 6-d gradual concentrate increase, followed by 1 wk of 65% concentrate (dry matter basis; Conc I), and 1 wk of RD and a final 2-wk 65% concentrate (dry matter basis; Conc II) phase. Digesta samples were collected from the rumen mat for bacterial 16S rRNA gene Illumina MiSeq (Illumina, Balgach, Switzerland) sequencing, and samples of particle-associated rumen liquid were obtained for measuring short-chain fatty acids, lactate, ammonia, and pH during RD (d 6), Conc I (d 19), and Conc II (d 39). The concentrate feeding caused a decrease of overall bacterial diversity indices, especially during Conc I. The genera Ruminococcus, Butyrivibrio, and Coprococcus were decreased, whereas Prevotella, Megasphaera, Lachnospira, and Bacteroides were increased in abundance. Supplementation of both feed additives increased the abundance of gram-positive and decreased that of gram-negative bacteria. Supplementation of AY enhanced cellulolytic bacteria such as Ruminococcus spp., whereas PHY decreased starch and sugar fermenters including Bacteroides spp., Shuttleworthia spp., and Syntrophococcus spp. Moreover, PHY supplementation increased butyrate percentage in the rumen in both concentrate phases. In conclusion, intermittent high-concentrate feeding altered the digesta-associated rumen bacterial community and rumen fermentation with more significant alterations found in Conc I than in Conc II. The data also showed that both feed additives had the most significant modulatory effects on the bacterial community, and their subsequent fermentation, during periods of low pH.     

Estimates of genetic parameters for feeding behavior traits and their associations with feed efficiency in Holstein cows

Residual feed intake (RFI) is commonly used to measure feed efficiency but individual intake recording systems are needed. Feeding behavior may be used as an indicator trait for feed efficiency using less expensive precision livestock farming technologies. Our goal was to estimate genetic parameters for feeding behavior and the genetic correlations with feed efficiency in Holstein cows. Data consisted of 75,877 daily feeding behavior records of 1,328 mid-lactation Holstein cows in 31 experiments conducted from 2009 to 2020 with an automated intake recording system. Feeding behavior traits included number of feeder visits per day, number of meals per day, duration of each feeder visit, duration of each meal, total duration of feeder visits, intake per visit, intake per meal [kg of dry matter (DM)], feeding rate per visit, and feeding rate per meal (kg of DM per min). The meal criterion was estimated as 26.4 min, which means that any pair of feeder visits separated by less than 26.4 min were considered part of the same meal. The statistical model included lactation and days in milk as fixed effects, and experiment-treatment, animal, and permanent environment as random effects. Genetic parameters for feeding behavior traits were estimated using daily records and weekly averages. Estimates of heritability for daily feeding behavior traits ranged from 0.09 ± 0.02 (number of meals; mean ± standard error) to 0.23 ± 0.03 (feeding rate per meal), with repeatability estimates ranging from 0.23 ± 0.01 (number of meals) to 0.52 ± 0.02 (number of feeder visits). Estimates of heritability for weekly averages of feeding behavior traits ranged from 0.19 ± 0.04 (number of meals) to 0.32 ± 0.04 (feeding rate per visit), with repeatability estimates ranging from 0.46 ± 0.02 (duration of each meal) to 0.62 ± 0.02 (feeding rate per visit and per meal). Most of the feeding behavior measures were strongly genetically correlated, showing that with more visits or meals per day, cows spend less time in each feeder visit or meal with lower intake per visit or meal. Weekly averages for feeding behavior traits were analyzed jointly with RFI and its components. Number of meals was genetically correlated with milk energy (0.48), metabolic body weight (?0.27), and RFI (0.19). Duration of each feeder visit and meal were genetically correlated with milk energy (0.43 and 0.44, respectively). Total duration of feeder visits per day was genetically correlated with DM intake (0.29), milk energy (0.62), metabolic body weight (?0.37), and RFI (0.20). Intake per visit and meal were genetically correlated with DM intake (0.63 and 0.87), milk energy (0.47 and 0.69), metabolic body weight (0.47 and 0.68), and RFI (0.31 and 0.65). Feeding rate was genetically correlated with DM intake (0.69), metabolic body weight (0.67), RFI (0.47), and milk energy (0.21). We conclude that measures of feeding behavior could be useful indicators of dairy cow feed efficiency, and individual cows that eat at a slower rate may be more feed efficient.     

Views of Western Canadian dairy producers on calf rearing: An interview-based study

Calf rearing practices differ among farms, including feeding and weaning methods. These differences may relate to how dairy producers view these practices and evaluate their own success. The aim of this study was to investigate perspectives of dairy producers on calf rearing, focusing on calf weaning and how they characterized weaning success. We interviewed dairy producers from 16 farms in Western Canada in the following provinces: British Columbia (n = 12), Manitoba (n = 2), and Alberta (n = 2). Participants were asked to describe their heifer calf weaning and rearing practices, and what they viewed as successes and challenges in weaning and rearing calves. Interviews were recorded, transcribed, and subjected to qualitative analysis from which we identified the following 4 major themes: (1) reliance on calf-based measures (e.g., health, growth, and behavior), (2) management factors and personal experiences (e.g., ease, consistency, and habit), (3) environmental factors (e.g., facilities and equipment), and (4) external support (e.g., advice and educational opportunities). These results provided insight into how dairy producers view calf weaning and rearing, and may help inform the design of future research and knowledge transfer projects aimed at improving management practices on dairy farms.     

Prevalence of disorders in preweaned dairy calves from 731 dairies in Germany: A cross-sectional study

The objective of this cross-sectional study was to determine the prevalence of disorders in preweaned calves in 3 regions in Germany, exemplary for structural diversity in dairy farming. A farm visit was performed on a single occasion on 731 dairy farms in the northern, eastern, and southern regions of Germany between December 2016 and July 2019. Farms differed in herd size, geographical location, and management. In the northern region, the farms had a median of 90 milking cows and were often run as full-time family businesses, partly with external workers. The eastern region tended to have larger farms (a median of 251 milking cows), which were often large-scale agricultural enterprises with employees. In the southern region, the farms had a median of 39 milking cows and were often traditional family businesses, some of these being part-time businesses. Clinical examinations were performed on 14,164 preweaned dairy calves (median 12 calves per farm) by trained veterinarians. A complete data set was available for 13,656 calves. Almost half (42.0%) of the evaluated calves were classified as being affected by at least 1 of the common calf disorders. Omphalitis (O, 20.9%; n = 2,876) and diarrhea (D, 18.5%; n = 2,670) were the most frequently recorded diagnoses, whereas respiratory diseases (RD) were observed to a lesser extent (8.7%; n = 1,100). A striking feature was the fact that 7.1% (n = 987) of the calves were affected by more than 1 disorder at the same time (multimorbidity, M). The following combinations of disorders were frequently observed: O and D (n = 596), O and RD (n = 164), and D and RD (n = 140). Disorders such as O and D, as well as M, were predominantly observed in calves aged 2 wk. A gradual increase in the frequency of RD was observed with age. For all disorders except RD, male calves were more often affected than females. Omphalitis was predominantly diagnosed in the summer months, whereas RD, D, and M were more common in the fall. We detected several statistically significant differences in the prevalence of clinical signs and disorders in preweaned dairy calves between the 3 exemplary regions. The prevalence of RD was higher in the south (10.8%) than in the north (8.2%) and east (7.4%). In the north (33.2%), O was observed more frequently than in the other regions (east: 18.9%; south: 10.5%), whereas D was found less frequently in the north (13.8%) than in the east (21.6%) and south (20.0%).     

The effectiveness of a nurse-managed perinatal smoking cessation program implemented in a rural county.

The present study (a) examined the effectiveness of a nurse-managed smoking cessation program, that was totally integrated into routine perinatal care, on the cessation rates of pregnant smokers in a rural community, and (b) assessed the subject characteristics associated with smoking cessation success. Data were collected from a convenience sample of 194 pregnant women who stated that they were smokers at the onset of their pregnancies. The study compared the effects of usual care (n = 93) versus the Smoke Free Baby & Me program (n = 101), which included the American Cancer Society's Make Yours a Fresh Start Family program. Smoking status was measured by self-report and urinary cotinine at four points during pregnancy and postpartum. At the postpartum visit, more women in the experimental group reported that they were not smoking compared with those in the control group (37.3% vs. 16.7%), Pearson's chi2 (n = 87) = 4.37, p = .037, and they had higher validated (urinary cotinine <200 ng/ml) smoking cessation rates (n = 80, t = 2.449, p = .017) if they had quit smoking by the first prenatal visit. Smoking cessation was positively associated with level of education and negatively associated with gravidity, parity, the number of smokers in the household, and the number of cigarettes smoked per day at the first prenatal visit. Significant discordance was found between self-report and urinary cotinine assays at all prevalence points, regardless of group. In conclusion, this nurse-delivered program integrated into perinatal care influenced the smoking behaviors of "recent quitters" but had no effect on those who reported smoking at the first prenatal visit. Implications for clinical practice are discussed.     

RESPIRATORY DEFICIENT MUTANTS OF BOTTOM BREWER'S YEAST. I. FREQUENCIES AND TYPES OF MUTANT IN VARIOUS STRAINS

Four strains of bottom brewer's yeast used in Czech breweries did not differ substantially from one another in their frequencies of spontaneous respiratory-deficient (RD) mutants as tested by the triphenyl tetrazolium chloride (TTC) overlay technique. These frequencies amounted to 1.1–1.4% of the total viable cell number after cultivation in bottom layers of wort. The strain which had the highest rate of aerobic growth gave a spontaneous mutation frequency of 0.5% in shaken cultures. In comparison with the TTC overlay technique, WL-Difco-agar with brom cresol green gave lower estimations of the frequency of production of spontaneous RD mutants. The RD mutants isolated can be divided into II groups on the basis of their cytochrome content (particularly cytochromes b and c) after aerobic growth. Of the 34 RD isolates tested, only 3 produced considerable numbers of revertants to respiratory sufficiency. These 3 mutants were derived from the same original strain, had the same cytochrome type, and had very slow growth rates. All RD mutants isolated had slower growth rates under aerobic conditions and reduced fermentation rates in static cultures in comparison with the parent types.     

Automated measurement of changes in feeding behavior of milk-fed calves associated with illness

There is a need for improved methods of detecting illness among group-housed milk-fed calves. In 4 separate experiments, we examined whether illness in group-housed dairy calves fed with an automated milk feeder changed their feeding behavior, and whether these changes were affected by low (n = 26) or high (n = 38) milk rations. All calves were subjected to regular health checks that included general condition, rectal temperature, lung auscultation, and fecal scoring. We match paired calves that succumbed to illness with healthy calves on the same feeding allowance. In the days following clinically identified illness (gastroenteric or respiratory affections), sick calves fed high allowances of milk or milk replacer decreased milk intake (−2.59 ± 0.7 L/d) and frequency of visits to the milk feeder (−2.43 ± 0.3 visits/d), and increased the duration of each visit to the milk feeder (1.66 ± 0.5 min/visit) compared with healthy calves fed at the same allowance. However, sick calves fed a low allowance of milk or milk replacer only decreased the duration of each visit to the milk feeder (−1.35 ± 0.2 min/visit) compared with healthy calves. Feed allowance affected feeding behavior associated with illness of milk fed calves.     

The biologically relevant unit for the analysis of short-term feeding behavior of dairy cows

To determine whether visits or meals are the most biologically relevant unit of short-term feeding behavior, we analyzed 209,025 records of visits to feeders by 37 cows. Two feeds were used that differed in protein content. Cows were divided into control groups for the low and high protein feeds and a choice group that had access to both. Daily number of visits and intake per visit were very variable. Cows fed low protein feed had lowest daily intakes, but single-visit characteristics were poorly correlated with daily intake. The probability of cows ending a visit did not change greatly with visit length. Log-normal models were used to estimate individual meal criteria (44.7+/-2.1 min), and visits were grouped into meals. Meal duration (36.9+/-1.3 min) and daily number of meals (6.1+/-0.1) were not affected by treatment. Feeding rate and intake per meal were lowest for cows fed low protein feed. Meal size decreased systematically during the day. The probability of cows ending and starting a meal increased with meal length and interval between meals, as predicted by the satiety concept. Meals are, therefore, a biologically relevant unit of short-term feeding behavior and visits are not.     

Within-day feeding behavior of lactating dairy cows measured using a real-time control system

The suitability of a statistical model for describing within-day feeding behavior, and potential relationships between model parameters and commonly measured experimental variables were examined. Forty multiparous, midlactation Holstein cows were fed using a real-time control system to record the date of each visit to a feeder, entrance time, exit time, and feed consumed over a 6-wk period. Daily feed consumption, number of visits, meal duration, and within-visit rate of food intake were then calculated. Two peaks in within-day rates of feed intake were indicated, suggesting that feeding activity was randomly distributed around each peak, that is, binormal. Parameters describing the distributions (means, standard deviations, and the percentage of total feeding activity associated with each peak) were estimated. An adjusted average of 91% of the variation in within-day feeding activity was explained by the binormal model. Relationships between model parameters and commonly measured experimental variables were also identified; behavioral traits were correlated with total feed intake. Feeding activity patterns in literature data were also amenable to reanalysis by the binormal model. Lactating cows consistently exhibited a distinct diurnal pattern in feeding activity; they were most active near sunrise and again near sunset (crepuscular). Effects of various management operations (e.g., feeding and milking times and frequencies, and lighting) on within-day feeding patterns remain to be established, although a statistical model for evaluating them is now available. The patterns may have important implications for scheduling management activities to maximize feed intake and production.     

Coupling of soil regeneration,food security,and nutrition outcomes in Andean subsistence agroecosystems

To sustain the livelihoods of smallholder farmers globally, improved human nutrition must not sacrifice future agroecosystem productivity. We gathered environmental, agricultural management, food security (FS), and normalized child height for age (HAZ; children age < 2y) data from 297 farming households to test whether enhanced FS and nutrition goals can be aligned with agroecosystem maintenance in Andean farming systems that rely heavily on the local environment. Our results demonstrate many expected relationships between environment, agriculture, and nutrition in these communities’ households, for example between ecosystem biomass production and manuring rates, between total household crop production and FS, and between HAZ and child diet diversity. However, increased FS status evaluated by households was unrelated to HAZ as an indicator of nutrition status. By contrast, better child nutrition and feeding practices in some households were associated not with total production but with farming practices that sustain soils and secure higher per-hectare crop yields: longer fallows, greater crop diversity, and smaller cropped areas. These results may be explained by the tendency for agricultural practices correlated with household food insecurity (e.g. reduced manure inputs, greater cropped area) to increase labor and impede appropriate feeding and child nutrition while they accelerate environmental degradation. Crop production imperatives for food supply can thus degrade soils without delivering improved nutrition. Meanwhile, more sustainable practices in households with better child nutrition (e.g. smaller, better-manured crop areas) may address time barriers to effective care and feeding. We discuss challenges and opportunities based on these results for meeting both nutrition and environmental goals.     

Comparison of DNA Extraction and PCR Setup Methods for Use in High-Throughput DNA Barcoding of Fish Species

DNA barcoding is a sequencing-based method that can be used for the identification of fish species in a regulatory setting. The objective of this study was to compare modified versions of three DNA extraction kits (i.e., Qiagen DNeasy Blood and Tissue Kit, Sigma-Aldrich Extract-N-Amp Kit; and Life Technologies MagMax-96 DNA Multi-Sample Kit) and two polymerase chain reaction (PCR) setup methods (manual vs. automated) for use in DNA barcoding, with a focus on minimizing time, costs, and labor. DNA was extracted from 83 fish products using each of the three kits and the results were compared based on sequencing success and sequencing quality parameters. A subset of 14 fish products was also tested in triplicate to compare PCR setup methods. Initially, reduced sequencing success was observed with the MagMax Kit (88 %) compared to the other two kits (95–96 %); however, after PCR and sequencing were repeated for DNA samples that initially failed, all three methods showed very high sequencing success (98–99 %). Overall, the modified Extract-N-Amp Kit offered the greatest reduction in time and costs, while the DNeasy Blood and Tissue Kit produced sequences with the highest quality and highest initial success rates. Automation of the PCR setup process resulted in slightly greater success (100 %) compared to manual PCR setup (98 %), and reduced the potential for human error that may result from manual pipetting. The results of this study demonstrate the advantages of incorporating rapid and/or automated methods into the DNA barcoding workflow, especially with regard to high-throughput operations.     

Gabapentin for smoking cessation: a preliminary investigation of efficacy.

Gabapentin affects the glutamate and gamma amino butyric acid (GABA) neurotransmitters through which it may facilitate smoking abstinence. To obtain preliminary estimates of efficacy of gabapentin for smoking cessation, we conducted a single-arm, open-label study of gabapentin, 1,800-mg/day administered in three equal divided doses for 8 weeks. A total of 50 adult smokers were enrolled. All participants received a brief behavioral intervention at each medication visit. A total of 37 participants completed all follow-up assessments. At end-of-treatment the biochemically confirmed point-prevalence and prolonged smoking abstinence rates were 28% (95% CI=16%-42%) and 24% (95% CI=13%-38%), respectively. At 6 months, the biochemically confirmed point-prevalence and prolonged smoking abstinence rates were 20% (95% CI=10%-34%) and 16% (95% CI=7%-29%), respectively. Among subjects who continued to smoke and completed the follow-up assessments, the reported number of cigarettes smoked per day (mean+/-standard deviation) was significantly less than at baseline: -10.0+/-8.2 (p<.001). Adverse effects were minor and well tolerated. Our results suggest that gabapentin may increase smoking abstinence. An adequately powered randomized clinical trial assessing different doses of this drug against a placebo would be the reasonable next step.     

Sorption and desorption behavior of organotin compounds in sediment-pore water systems

Sediments contaminated with organotin compounds (OTs), in particular triorganotins (TOTs), are abundant in areas with high shipping activities. To assess the possible remobilization of these highly toxic compounds from such sediments, a profound understanding of their sorption/desorption behavior is necessary. In this work the extent and reversibility of sorption of OTs to sediments has been investigated using contaminated freshwater harbor sediments and two certified OT containing marine sediments. Experiments conducted with perdeuterated OTs showed that sorption of OTs to sediments is a fast and reversible process involving primarily particulate organic matter (POM) constituents as sorbents. The organic carbon-normalized sediment-water distribution ratios (DOC, expressed in L/kgOC) determined in the laboratory were consistent with in-situ DOCs obtained from OT concentrations measured in sediment and pore water samples from two dated sediment cores. For both butyl- and phenyltin compounds the log DOC values were in the range of 4.7-6.1, and the following sequence was observed: DOC (tri-OT) > or = DOC (di-OT) > or = DOC (mono-OT). However, the differences were much less pronounced than would have been expected for hydrophobic partitioning of the corresponding compounds into POM. These results support our hypothesis from earlier work with dissolved humic acids that OT sorption to sediments occurs primarily by reversible formation of (innerspere) complexes between the tin atom and carboxylate and phenolate ligands present in POM. Because of the high DOC values (i.e. log DOC > or = 4) the diffusion of OTs from deeper sediments to the surface will be rather slow, and thus a major release from undisturbed sediments is not expected. However, because OTs readily desorb, any resuspension of contaminated sediments (e.g., by the tide, storms or dredging activities) will lead to enhanced OT concentrations in the overlaying water column. Furthermore, in contrastto polycyclic aromatic hydrocarbons (PAH) where large fractions may be tightly bound (in)to soot or other carbonaceous materials, OTs will be more readily bioavailable due to the fast and reversible sorption/desorption behavior.     

Use of Front-Face Fluorescence Spectroscopy to Differentiate Sheep Milks from Different Genotypes and Feeding Systems

The objective of the present study was to assess the potential of front-face fluorescence spectroscopy coupled with chemometric tools for the evaluation of the quality of milk samples according to the feeding system and genotype. Fifty (n = 50) ewe's milk samples were scanned after excitation set at 250, 290, 322, and 380 nm and emission set at 410 nm. Thirty out of the 50 samples composed the first trial and were obtained from two different genotypes (i.e., Comisana versus Sicilo-Sarde); the second trial was composed of 20 samples obtained from the Sicilo-Sarde genotype with two different feeding systems in pen (soybean versus scotch bean). Milk samples were divided into four groups named Sicilo-Sarde with pasture feeding (Spas), Comisana with pasture feeding (Cpas), Sicilo-Sarde feeding on scotch bean (Ssco), and Sicilo-Sarde feeding on soybean (Ssoy). The factorial discriminant analysis was applied to the: (i) four groups (i.e., Spas, Ssco, Ssoy, and Cpas) and (ii) three groups composed only of Sicilo-Sarde genotype (i.e., Spas, Ssco, and Ssoy). Considering the four groups, the best result was obtained with the excitation vitamin A spectra since correct classification amounting to 76% was observed. When the factorial discriminant analysis was performed with the three groups belonging to the Sicilo-Sarde genotype, the best result was obtained again with vitamin A spectra (i.e., emission and excitation spectra) since 88.6% of correct classification was observed. Concatenation technique applied to the five fluorescence spectra improved the rate of classification between the four groups since 44 out of 50 samples were correctly classified. No misclassification was observed between milk samples collected from ewes with pasture feeding from the pen feeding. It was concluded from the obtained results that fluorescence spectroscopy could be considered as a powerful tool for differentiating between raw milks according to both genotype and feeding system.     

Inhibition of oxytocin release and milk let-down in postpartum primiparous cows is not abolished by naloxone

About 10% of primiparous cows have no milk ejection during the first milkings after delivery. Therefore, 17 Brown Swiss dairy cows in their first lactation were used to evaluate the extent of disturbed milk let-down and the corresponding oxytocin (OT) plasma values in the 1st 5 days after delivery. The first milking was 9-22 h after parturition and served for classification of the cows to groups with inhibited (INH), bimodal (BIMO), or normal (NOR) milk let-down. The OT plasma levels before the start of manual teat stimulation and machine milking were comparably high during the first milking especially in NOR and BIMO cows. Ten minutes before the second milking (M2), 300 mg of the opioid antagonist naloxone was injected to test whether the disturbance was affected by the action of endogenous opioids on the neurohypophysis. The milk yield was not influenced by the naloxone treatment, and the INH cows had milk ejection only after a vaginal stimulation. Afterwards, the cows were milked twice every day, until the milk let-down and the OT release were unaffected (equal to control milking). Then, at the next milking, the cows were injected with 300 mg morphine 10 min before milking. The central OT release in response to manual teat stimulation and machine milking was completely blocked in all cows, but a vaginal stimulation was able to abolish this block, at least partially, in 16 cows. Thus, morphine produced a milk let-down characteristic as in the INH cows during the first three milkings. For the following milking, the cows were pre-treated with 300 mg naloxone (-15 min) plus 300 mg morphine (-10 min) before milking. The OT release and the milk yields were unaffected when compared with the control milking. This experiment demonstrates that exogenous opioids can affect the central release of OT in a naloxone-reversible manner even very soon after parturition. However, endogenous opioids are probably not the main mediators of disturbed central OT release and alveolar milk ejection in post-partum primiparous cows.     

应用渗透膜高密度培养富硒螺旋藻

应用透析袋(OT法)组装光生物反应器,与鼓泡式生物反应器(AB法)和摇瓶(SB法)进行对比实验,探讨利用渗透膜建立高密度培养富硒螺旋藻(Se-SP)方法的可行性。称质量法监测并推算藻细胞生长率和最大生物量,荧光光度法测定Se-SP及其培养液中硒含量和形态变化,分光光度法检测Se-SP中总蛋白(TP)、藻蓝蛋白(PC)、叶绿素a(Chla)、总胡萝卜素(Caro)、水溶性多糖(SPS)及巯基(-SH)含量等主要营养构成,培养液中无机碳(IC)和有机溶解碳(DOC)的含量采用自动分析仪测定。结果发现：OT法培养Se-SP的最大生物量可达9.6g/L,是AB和SB方法培养的3～5倍,其中有机硒转化率及TP、PC、Chla、SPS和-SH等主要营养成分的含量均有明显提高。相应地,培养基中 IC剩余减少, DOC无明显累积。结果提示,OT法可实现Se-SP高密度培养,并有望获得优质Se-SP产品,其优势体现在高细胞增殖速率、高有机硒转化率、高无机营养源消耗率和低有机碳的积累,便于培养液的再生利用,减少废液污染。     

大豆蛋白-聚乙烯醇-层状硅酸盐粘土复合薄膜的性能研究

通过溶液流延法制备了大豆蛋白/聚乙烯醇/层状硅酸盐黏土(Laponite RD)共混物薄膜,研究了纳米黏土的添加量对薄膜的热性能、机械性能以及水蒸气阻隔性能的影响。随着Laponite RD的添加,薄膜熔融峰首先向低温方向偏移(0%~10%Laponite RD),然后随着Lapontite RD含量的继续增加,熔融峰又向高温方向偏移。Laponite RD的添加增强了薄膜的水蒸汽阻隔性能,对比不同相对湿度(RH)下的水蒸气透过性(WVP),75%RH下的WVP要高于50%RH下的WVP。随着Laponite RD添加量的增加,拉伸强度和断裂伸长率同样呈现先升后降的趋势。在较高的相对湿度下(75%RH),由于水分子的塑化作用,薄膜的拉伸强度和断裂伸长率相对50%RH下更低。     

Effects of rice dreg protein and its hydrolysate on growth performance and small intestine morphology of early-weaned rats

BACKGROUND: Protein hydrolysate has more efficient peptide absorption and less hypertonic protein absorption. This study aims to investigate the influences of rice dreg (RD) protein and its hydrolysate on growth and somatropic axis in early‐weaned Sprague‐Dawley rats in comparison with soybean (SB) protein. RESULTS: Compared with a SB diet control, a rice dregs protein hydrolysate (RD‐H) diet decreased average daily feed intake and feed/gain in weeks 1 (P < 0.01) and 2 (P < 0.05), while an RD diet decreased average daily feed intake and feed/gain in week 1 (P < 0.01). Average daily body gain exhibited no significant differences between either treatment during the 28‐day period. After 28 d, villus height and lamina propria depth of jejunum and duodenum were greater in the RD‐H treatment than in RD and control treatments (P < 0.01), while serum urea nitrogen concentration was lower in RD and RD‐H treatments than in the control (P < 0.05). There were no differences in serum growth hormone concentration, hepatic and muscle insulin‐like growth factor‐1 expression, and muscle growth hormone receptor expression at 7 and 28 d (P > 0.05), but hepatic growth hormone receptor expression was higher in RD‐H treatment than in RD and control treatments after 7 d (P < 0.05). CONCLUSION: Results showed that RD and RD‐H diets improved feed utilisation efficiency in the first 2 weeks post‐weaning and small intestine morphology at 28 d post‐weaning for an early‐weaned mammal compared with a SB diet. Copyright © 2010 Society of Chemical Industry     

Profile of pediatric aphakics over 10 years in a tertiary eye care – A retrospective study

AimTo investigate the outcome of contact lens (CL) fitting in aphakic children following lensectomy for congenital cataract.MethodRetrospective data of 205 aphakic children who visited for CL fitting following lensectomy from 2008 to 2018 were collected. Data includes the demographic details, CL parameters in first and last visit, hours of CL wear, reason for discontinuation of CL, surgical procedures underwent and years of follow up.Results205 (148 unilateral and 57 bilateral) aphakic children comprised of age group, < 1 month (n = 48), 1–3 months (n = 37), 3–6 months (n = 68), 6–12 months (n = 10), >12 months (n = 42). 173/205(84.39%) children were fitted with rigid gas permeable (RGP) and 32/205(15.6%) were fitted with soft CL at their first visit. 10 children had shifted to soft CL in their follow-up visits due to intolerance to RGP. 97/205(47.32%) children continued CL (55RGP, 42SCL) till the last follow-up for 2.17 ± 2.36 years and wore lens for 3.7 ± 3.65 h per day. Number of lenses replaced was 2 lenses (median) and maximum of 9 lenses over a period of 1–8 visits. The maximum visual acuity achieved was up to 0.2 log Mar units at the youngest age of 4 years on successful CL wear. 60/205(29.26%) children discontinued lenses at different follow-up visits due to IOL implantation(n = 28),using spectacles due to handling difficulty, child uncooperative to lens wear and lens fitting issues(n = 32). 48/205(23.41%) were lost to follow-up after the first visit. The average K (7.46 ± 0.43 mm) showed significant correlation to lens base curve in first visit (7.48 ± 0.41 mm) whereas flat K (7.71 ± 0.38 mm) showed significant correlation in the last visit (7.46 ± 0.39 mm) (p < 0.005). This was well described by a significant diameter change of 8.68 ± 0.31 mm to 9.42 ± 1.77 mm (p < 0.005) at the first and last visit respectively. The refractive error showed a significant difference between first (27.96 ± 5.33D) and last visit (21.97 ± 6.85D) (p < 0.005).ConclusionThis study witnessed successful contact lens wear in only half of the children. The visual rehabilitation following lensectomy depends on right CL choice and close follow-up.