Effects of dietary 60 g kg−1 dried distiller's grains in least‐cost practical diets on production and gut allochthonous bacterial composition of cage‐cultured fish: comparison among fish species with different natural food habits

Dried distiller's grain (DDG) is considered as an alternative ingredient of dietary feed due to its high contents of protein, fibre and fat. In this study, 60 g kg^‐1 of DDG was used to feed grass carp (Ctenopharyngodon idella), bluntnose black bream (Megalobrama amblycephala), gibel carp (Carassius gibelio) and black carp (Mylopharyngodon piceus) for 8 weeks, and its effect on fish production and gut allochthonous microbiota was investigated for the development of a suitable fish feed high in nutrients and low in cost for polyculture freshwater fish. DDG supplementation resulted in the less weight gain and higher feed conversion ratio of black carp (P < 0.05), but had no significant effects on other fish or parameters. PCR–denaturing gradient gel electrophoresis (DGGE) analysis indicated that all four fish species had some common and unique bacteria in their digestive tracts, and the gut microbiota of bluntnose black and gibel carp fed the control diet and DDG diets were very similar (Cs > 91%); of them, the total counts of intestinal bacteria studied by qPCR increased in grass carp (P < 0.05) and depressed in black carp (P < 0.05) when fed dietary DDG. Thus, we assumed that dietary DDG modulated production and gut microbiota of fish in a host‐specific way.     

开菲尔粒中产球菌样细菌素乳酸菌的分离与鉴定

利用MRS选择培养基筛选开菲尔粒中具有抑菌作用的乳酸菌。采用牛津杯琼脂扩散法,结合对理化抗性特征的鉴定、抗菌谱测定、菌落形态与特征和生理生化实验鉴定,结合伯杰氏手册对分离到的菌株进行鉴定。生理生化反应为乳酸菌,菌落形态与特征为球菌,对多数的革兰氏阴性菌有抑制作用,该菌株为乳酸乳球菌二乙酰乳酸亚种。鉴定分离为产球菌样细菌...     

Glass transition behavior of corn distillers dried grains with solubles (DDGS)

Distillers dried grains with solubles (DDGS), a major co-product from the corn ethanol industry, has high feed value for its chemical composition. The ratio of wet distillers grains (WDG) and condensed distillers solubles (CDS) added during the production process determines the chemical composition of DDGS. Effect of changing this ratio and the influence of moisture content on glass transition behavior of DDGS was studied. Five prediction models were evaluated to explain the glass transition of DDGS. The mixed trends in the result indicated the complex behavior of DDGS particles and revealed that both moisture content and chemical composition impact the glass transition behavior of DDGS. Onset glass transition temperature ranged from 20 to 30 °C depending on the chemical composition. Kwei equation predictions were better than the predictions by Gordon-Taylor equation. The glass transition temperature of DDGS can be mathematically explained by combining the moisture content and chemical components protein, fiber, glycerol, and sugar percent. The artificial neural network (ANN) model gave a better prediction of onset and midpoint glass transition temperature of DDGS and this might be due to the accurate mapping of the interaction between chemical components.     

Factors that modify early and late reproductive phases in oilseed rape (Brassica napus L.): Its impact on seed yield and oil content

Oilseed rape yield potential could be improved lengthening the duration of the late reproductive phase by increasing the number of grains per unit area. Photoperiod sensitivity could be used as a tool to manipulate the reproductive phase and thereby the number of grains. The aim of this study was to assess (i) the effects of different combinations of photoperiod on the duration of different phases and (ii) analyze how the changes in that duration affect yield (and its components) as well as oil seed content in oilseed rape. Field experiments were conducted in a factorial combination of three cultivars and three photoperiod regimes: natural photoperiod (NP) which represents the control and extended photoperiod of 6 h over NP (NP + 6) during emergence (E)-flower buds visible (FBV) and FBV-maturity (M) arranged in a randomized complete block design with three replicates, during two years representing three environments. Results showed that oilseed rape evidenced photoperiod responses during vegetative and early reproductive phases. Due to the lack of correlation between the duration of the vegetative and reproductive phases, it is possible to speculate the vegetative period may be altered independently of the modification of the rest of the phases. The positive relationship between grain number per m² and the duration of the late reproductive phase suggests that yield could be increased by lengthening the duration of that phase. Thus, regardless of the effect on the previous phase, the photoperiod sensitivity found in the early reproductive phase opens the possibility to manipulate the relative durations of vegetative and reproductive phases. Therefore, the length of the reproductive phase will be increased at the expense of a reduction in the duration of the vegetative phase, but without changing the whole duration of the crop cycle. This strategy could increase yield in oilseed rape in the future. Variations in yield were mostly explained by changes in the grain number per unit area without significant correlation with grain weight. However, a negative relationship between grain weight and grain number was found, showing a slight counterbalance in yield, by decreasing the grain weight. Since oil concentration appeared to be a more conservative attribute, increases in crop yield through a higher grain number per unit area would be a suitable strategy for improving oil yield as no reductions in oil concentration can be expected.     

Effects of gamma irradiation on mycotoxin disappearance and amino acid contents of corn,wheat, and soybeans with different moisture contents

The effects of gamma irradiation on degradation of aflatoxin B₁ in wheat, corn, and soybeans and of T-2 toxin in wheat, deoxynivalenol (DON) in soybeans, and zearalenone in corn at 9, 13, and 17% moisture were studied. Radiation doses of 5, 7.5, 10 or 20 kGy were applied to spiked grain samples, and the residual toxins were measured using an enzyme linked immunosorbent assay (ELISA). Irradiation doses of up to 20 kGy did not significantly affect aflatoxin B₁ in any of the three grains, but significant reductions occurred in T-2 toxin, DON, and zearalenone concentration at doses of 10 or 20 kGy and in T-2 toxin at the 7.5 kGy dose. Two-way analysis of variance with Tukey's Multiple Range Test showed no significant interaction between radiation dose and grain moisture level. Irradiation of the ground grains at doses higher than 5 kGy resulted in small, but significant, losses of lysine in corn (only at 7.5 kGy), wheat, and soybeans, and methionine was reduced in wheat and corn samples. In some cases, phenylalanine decreased in corn and wheat, and histidine levels in wheat were reduced in samples receiving 7.5 kGy of irradiation. Other essential amino acids were not affected significantly by irradiation.Contribution No. 94-114-J of the Kansas Agricultural Experiment Station.     

基于定量PCR方法初步分析西藏开菲尔粒中细菌与酵母菌数量变化

运用实时荧光定量PCR方法分析西藏开菲尔粒中细菌与酵母菌的数量变化规律,需要有效提取其微生物总基因组DNA。本文通过同时添加溶菌酶与溶壁酶优化实验方案,成功获得西藏开菲尔粒中微生物的总基因组DNA。荧光定量PCR分析提取自培养1、4、8和12周的西藏开菲尔粒的微生物总基因组DNA,结果显示:4个时间点细菌16S rRNA与酵母菌26S rRNA基因拷贝数均分别约为每微升107拷贝与105拷贝,表明细菌与酵母菌的数量相对稳定。该结果为进一步研究西藏开菲尔粒中细菌与酵母菌间的共生关系奠定了一定的基础。     

鲜啤酒糟饲喂西门塔尔种母牛试验研究

[目的]为了探讨鲜啤酒糟对西门塔尔种母牛产奶量的影响.[方法]选择健康泌乳正常的西门塔尔母牛30头,依据胎次、产奶量、产奶天数分为3组,每组10头.试验A组在基础日粮中加喂鲜啤酒糟10 kg/头·日;试验B组在基础日粮中增加配合精料1.5 kg/头·日;对照组饲喂基础日粮.[结果]表明,试验A、B组头日均增奶3.11 ...     

不同栽培措施对超级稻强、弱势粒品质的影响

[目的]探究不同栽培措施对超级稻强、弱势粒品质及淀粉特性的影响,以期为改善稻米品质即水稻强、弱势粒品质的协同提高提供理论指导和实践依据.[方法]以超级稻甬优2640和武运粳24为供试材料,大田种植条件下,设置氮空白区(ON)、当地农民习惯(LFP)、优化栽培管理1(T1)和优化栽培管理2(T2)4个处理,每个处理设置3...