可改良棉粕蛋白的菌株选育及其发酵

棉粕蛋白质含量高达38％~50％,然而作为饲料其蛋白质品质较差,饲料利用率较低。为提高其蛋白质利用率,从自然界筛选出了能够高效降解棉粕大分子蛋白质的优良菌株4株,经生化与分子生物学试验鉴定为Bacillus subtilis(2株,编号为H1和H7),Bacillus cereus (1株,编号为H9)和Aspergillus niger (1株,编号为P1)。通过单菌及组合发酵实验比较发现:最适宜菌种组合为B. subtilis(H1)和A. niger (P1)。两菌株组合发酵后,棉粕TCA-NSI(三氯乙酸氮溶指数)提高了25.34%,小分子多肽含量提高了11%,游离必需氨基酸提高了24%,蛋白质的体外消化率由44.56%提高到了78.61%,明显高于其他菌种组合,研究结果表明其组合发酵可有效改良棉粕蛋白品质,显著提高棉粕蛋白的饲用价值。     

Influence of urea calcium mixture supplementation on ruminal fermentation characteristics of beef cattle fed on concentrates containing high levels of cassava chips and rice straw

The purpose of this study was to evaluate the effects of various N sources in concentrates containing high levels of cassava chips, with rice straw as the basal forage, on rumen ecology, rumen microbial counts, microbial crude (CP) protein synthesis, and digestibility of nutrients. Four ruminally fistulated crossbred (Brahman × native) beef steers with initial body weight (BW) of 400 ± 40.2 kg were randomly assigned according to a 4 × 4 Latin square design. The dietary treatments were different sources of N in the concentrates and were: T1 = urea (control; urea); T2 = soybean meal (SBM); T3 = urea CaCl₂ mixture (U-Cal); T4 = urea CaSO₄ mixture (U-Cas). All steers were kept in individual pens and supplemented with concentrate at 5 g/kg of BW daily. The experiment was 4 periods, and each lasted 21 d. During the first 14 d, all steers were fed their respective diets ad libitum and for during the last 7 d, they were moved to metabolism crates for total urine and fecal collection. Dry matter intake ranged from 9.8 to 10.5 kg daily and was not altered by diet, while digestibility of NDF differed among treatments and was highest with U-Cas supplementation (P<0.05). Ruminal NH₃ N and plasma urea N with U-Cal, U-Cas, and SBM diets were lower compared with the urea supplemented group (P<0.05). Ruminal volatile fatty acid concentrations were not altered by treatments. Total viable, and cellulolytic bacteria, differed among treatments and were highest with U-Cas (9.1 × 10¹¹, and 4.0 × 10⁹ cfu/mL, respectively). In addition, efficiency of rumen microbial CP synthesis based on organic matter (OM) truly digested in the rumen was increased by SBM or U-Cal supplementation, and was highest with U-Cas supplementation (18.2 g of N/kg of OM truly digested in the rumen). Supplementation of U-Cas to a concentrate containing a high level of cassava chips improved rumen ecology and microbial CP synthesis in beef cattle, suggesting that urea calcium mixtures can replace soybean meal or urea in beef cattle diets without adverse affects on rumen fermentation and other rumen parameters.     

Feeding soybean meal increases the blood level of isoflavones and reduces the steroidogenic capacity in bovine corpora lutea,without affecting peripheral progesterone concentrations

Thirty-three Holstein-Friesian cows were followed from 14 days pre partum until the fourth ovulation post partum. Housing conditions and basic ration were identical for all animals. Concentrates were individually supplemented according to the daily milk production level, using two different types of protein rich concentrates: soybean meal and rapeseed meal. Soybean and rapeseed meal are known to be respectively high and low in isoflavones. Cows were randomly divided into three groups and blocked for parity. Group I (n = 11) was supplemented with soybean meal and acted as control group. Groups II (n = 11) and III (n = 11) were respectively supplemented with soybean and rapeseed meal and were subjected to a biopsy sampling of the corpus luteum at day 9 of the first three postpartal estrous cycles.Soybean meal supplementation to lactating dairy cows (1.72 kg on average) induced an increase in the blood concentration of equol, dihydrodaidzein, o-desmethylangolensin in both soy groups and resulted in a reduced area occupied by steroidogenic (P = 0.012) and endothelial cells (P = 0.0007) in the luteal biopsies. Blood concentrations of equol and glycitein were negatively correlated with the areas occupied by steroidogenic (r = −0.410 with P = 0.0002, respectively r = −0.351 with P = 0.008) and endothelial cells (r = −0.337 with P = 0.01, respectively r = −0.233 with P = 0.085) in the 3 first estrous cycles. The latter however did not affect the diestrous peripheral blood progesterone concentration.     

饲料中棉粕替代鱼粉蛋白对草鱼的生长、血液生理指标和鱼体组成的影响简

以初始体重(100.0±0.29)g的草鱼为研究对象,通过8周的生长实验,研究饲料中棉粕替代鱼粉蛋白对草鱼的生长、饲料利用,血液生理指标和鱼体生化组成的影响。实验设置7种等氮等能饲料,对照组(C)以鱼粉为唯一蛋白源,其余6组分别以棉粕替代饲料中鱼粉蛋白的20%(R20)、40%(R40)、60%(R60)、80%(R80)、90%(R90)、100%(R100)。研究结果表明:随着饲料中棉粕含量的升高,草鱼特定生长率呈下降的趋势,当替代比例达到60%,显著低于对照组(P0.05);饲料效率、蛋白质贮积率和能量贮积率随着饲料中棉粕含量升高而显著降低(P0.05)。通过折线法分析,在实验条件下,棉粕可以替代鱼粉蛋白的43.3%而不影响草鱼的生长。各组草鱼之间血清谷丙转氨酶、谷草转氨酶和甘油三酯含量无显著差异(P0.05);总胆固醇、高密脂蛋白胆固醇和低密胆固醇呈现下降趋势,当替代水平达到40%显著低于对照组(P0.05)。棉粕替代鱼粉蛋白显著影响鱼体的水分含量(P0.05),当替代比例达到80%,鱼体的水分含量显著高于对照组(P0.05);各组之间鱼体的蛋白质和灰分含量无显著性差异(P0.05)。R20组的鱼体脂肪和能量含量显著高于对照组(P0.05),R100组的鱼体脂肪和能量含量显著低于对照组(P0.05),其他各组之间和对照组无显著性差异(P0.05)。     

Synergistic effects of heat and diatomaceous earth treatment for the control of Plodia interpunctella (Lepidoptera: Pyralidae)

Plodia interpunctella is a major economic pest that commonly infests most stored and processed agricultural products. Currently, heating at 50–60°C for at least 48 h is applied in facilities for disinfestation. However, this condition requires a great deal of time and expense. To improve the control efficiency of this system, we conducted combined treatments with heating and diatomaceous earth (DE), which is known to be toxic to pest insects. The DE effect was compared to heating at 25°C or 40°C to wandering fifth instar larvae, which is the stage most tolerant to heat. When larvae were brushed with DE powder, mortality was only 15.0–18.3% at 25°C for 10 days, but rapidly increased to 100% at 40°C within 4 h post‐treatment. In addition, when larvae were kept in a plastic cage with DE [4 mg/L (w/v)], their mortality was 100% in 24 h at 40°C post‐treatment; otherwise mortality was only 8.8% without DE. Thus, the control efficiency of heating significantly improved with the combination of DE. These effects increased further at higher temperatures and with longer exposure. Our results clearly showed that DE treatment showed synergistic effects with heating systems for the control of P. interpunctella.     

蛋白酶产生菌LN01水解玉米黄粉蛋白的研究

玉米黄粉中含有约质量分数60%的蛋白质,但很难直接应用,必须进行预处理.本文以玉米黄粉为原料,利用蛋白酶产生菌LN01进行液体发酵,分别研究了液体接种量、初始pH、培养温度和培养时间等因素对LN01菌株水解玉米黄粉蛋白的影响.实验结果表明,LN01菌株水解玉米黄粉蛋白的最佳发酵条件为:初始pH值为6.0,液体种子接种量...     

Fish models in prion biology: Underwater issues

Transmissible spongiform encephalopathies (TSEs), otherwise known as prion disorders, are fatal diseases causing neurodegeneration in a wide range of mammalian hosts, including humans. The causative agents - prions - are thought to be composed of a rogue isoform of the endogenous prion protein (PrP). Beyond these and other basic concepts, fundamental questions in prion biology remain unanswered, such as the physiological function of PrP, the molecular mechanisms underlying prion pathogenesis, and the origin of prions. To date, the occurrence of TSEs in lower vertebrates like fish and birds has received only limited attention, despite the fact that these animals possess bona fide PrPs. Recent findings, however, have brought fish before the footlights of prion research. Fish models are beginning to provide useful insights into the roles of PrP in health and disease, as well as the potential risk of prion transmission between fish and mammals. Although still in its infancy, the use of fish models in TSE research could significantly improve our basic understanding of prion diseases, and also help anticipate risks to public health. This article is part of a Special Issue entitled Zebrafish Models of Neurological Diseases.     

Opportunities for avoidance of land‐use change through substitution of soya bean meal and cereals in European livestock diets with bioethanol coproducts

An analysis is presented which quantifies the potential for distillers dried grains with solubles (DDGS, a coproduct of wheat bioethanol production) to replace soya bean meal (SBM) and cereals in livestock rations. A major proportion of the SBM imported into Europe as a protein‐rich feedstuff for livestock comes from South America, where land‐use change (LUC) is associated with high carbon emissions. Production of DDGS can therefore reduce LUC in South America by substitution of SBM in animal feed. The analysis indicates that a single bioethanol distillery processing 1 million tonnes of wheat, and producing ca. 330 000 tonnes of DDGS per annum, would substitute at least 136 493 tonnes of whole soya beans grown on 47 725 ha of land, and save greenhouse gas emissions equivalent to 0.63 million tonnes CO₂ per annum. By growing sugar beet and wheat in an average ratio of 0.06 : 0.94 on 1 ha of land in Europe, the net area of agricultural land required to produce feed ingredients equivalent to 6.08 t of sugar beet pulp (SBP) and 1.72 t of DDGS associated with 2363 L of bioethanol, is reduced to 0.40 ha. This accounts for 0.42 ha of soya that is not required when DDGS displaces SBM, and 0.18 ha of wheat that is not required when DDGS and SBP displace wheat in livestock rations.     

Ecdysteroid-stimulated synthesis and secretion of an N-acetyl-D-glucosamine-rich glycopeptide in a lepidopteran cell line derived from imaginal discs.

Hormone-regulated processing of N-acetyl-D-glucosamine was studied in an insect cell line derived from imaginal wing discs of the Indian meal moth, Plodia interpunctella (Hübner). The cell line, IAL-PID2, responded to treatment with 20-hydroxyecdysone with increased incorporation of GlcNAc into glycoproteins. Cycloheximide and tunicamycin counteracted the action of the hormone. In particular, treatment with 20-hydroxyecdysone resulted in the secretion of a 5,000 dalton N-acetyl-D-glucosamine-rich glycopeptide by the IAL-PID2 cells. Accumulation of this peptide was prevented by the use of teflubenzuron, a potent chitin synthesis inhibitor. A glycopeptide of similar molecular weight was observed in imaginal discs of P. interpunctella treated with 20-hydroxyecdysone in vitro, under conditions that induce chitin synthesis. Although the function of the 5,000 dalton glycopeptide is not known, we believe that the PID2 cell line is a promising model for molecular analysis of ecdysteroid-regulated processing of aminosugars by epidermal cells during insect development.     

Downregulated Lipid Metabolism in Differentiated Murine Adipocytes by Procyanidins from Defatted Grape Seed Meal

Recent reports have proposed possible anti-obesity mechanisms for antioxidants involving increased energy expenditure, pre-adipocyte differentiation and proliferation, decreased lipogenesis and increased lipolysis, and fat oxidation. The aim of this study was to examine and to confirm the anti-obesity effect of the oligomeric and polymeric procyanidin fractions from defatted grape seeds. The lipid metabolism-related mRNA level in the mouse preadipocytes, 3T3-L1 cells, was determined to evaluate the anti-obesity effect of the phenolic fractions from a grape seed meal. Lipid accumulation was reduced by 19% of the control level by the procyanidin fraction originating from the grape seed meal. Emerging from the effect of the treatment on HSL and LPL mRNA expression, lipolytic enzyme activity was not involved in the anti-obesity effects of CPE and FPP from the defatted grape seed meal. We tested and confirmed in this study the effect of the biological activities of oligomeric and polymeric procyanidins from the defatted grape seed meal. It is suggested from the results of this brief study that further studies would be desirable to focus on the anti-obesity effect of the purified extracts of a defatted grape seed meal.