Treatment of tropical forages with exogenous fibrolytic enzymes: effects on chemical composition and in vitro rumen fermentation

The effects of three treatments of fibrolytic enzymes (cellulase from Trichoderma longibrachiatum (CEL), xylanase from rumen micro‐organisms (XYL) and a 1:1 mixture of CEL and XYL (MIX) on the in vitro fermentation of two samples of Pennisetum clandestinum (P1 and P2), two samples of Dichanthium aristatum (D1 and D2) and one sample of each Acacia decurrens and Acacia mangium (A1 and A2) were investigated. The first experiment compared the effects of two methods of applying the enzymes to forages, either at the time of incubation or 24 h before, on the in vitro gas production. In general, the 24 h pre‐treatment resulted in higher values of gas production rate, and this application method was chosen for a second study investigating the effects of enzymes on chemical composition and in vitro fermentation of forages. The pre‐treatment with CEL for 24 h reduced (p < 0.05) the content of neutral detergent fibre (NDF) of P1, P2, D1 and D2, and that of MIX reduced the NDF content of P1 and D1, but XYL had no effect on any forage. The CEL treatment increased (p < 0.05) total volatile fatty acid (VFA) production for all forages (ranging from 8.6% to 22.7%), but in general, no effects of MIX and XYL were observed. For both P. clandestinum samples, CEL treatment reduced (p < 0.05) the molar proportion of acetate and increased (p < 0.05) that of butyrate, but only subtle changes in VFA profile were observed for the rest of forages. Under the conditions of the present experiment, the treatment of tropical forages with CEL stimulated their in vitro ruminal fermentation, but XYL did not produce any positive effect. These results showed clearly that effectiveness of enzymes varied with the incubated forage and further study is warranted to investigate specific, optimal enzyme‐substrate combinations.     

耕作方式对豫西旱地麦-豆轮作田土壤理化特性和酶活性的影响

为探明耕作方式对豫西旱地麦-豆轮作田不同土层土壤理化特性和土壤酶活性的影响,设置免耕(NT)、旋耕(RT)和翻耕(PT)3种耕作方式,分析了定位试验9 a(2009—2019年)后小麦收获期的土壤容重、孔隙度和有机质、全氮、有效磷和速效钾含量,以及土壤脲酶、蛋白酶、转化酶和碱性磷酸酶活性,并运用相关分析和通径分析研究了土壤理化性质与土壤酶活性的关系。结果表明：不同耕作方式对土壤理化特性和酶活性具有显著的调控作用,其调控效应与其作业深度相关。RT较PT有利于降低0～15 cm土层但增加15～35 cm土层容重,NT较RT和PT显著降低了0～5、15～35、35～60 cm土层的土壤容重,土壤孔隙度变化规律与容重相反。各处理间土壤有机质、全氮、有效磷含量以及土壤脲酶、蛋白酶、转化酶和碱性磷酸酶活性在0～5 cm土层和15～35 cm土层规律一致,0～5 cm土层均以NT最优,分别较最低值处理(PT)显著提高16.7%、53.2%、15.9%、23.6%、18.0%、34.7%和29.0%;15～35 cm土层均以PT最优,分别较最低值处理(NT)显著提高18.3%、23.4%、53.4%、...     

覆盖方式对旱地小麦花后旗叶抗氧化生理及粒重形成的影响

于2017—2018年和2018—2019年,在西北中部旱作雨养农业区以冬小麦‘康庄974’为试验材料,设秸秆带状覆盖(SM)、地膜覆盖(PM)和无覆盖对照(CK)共3个栽培处理,分析不同覆盖方式对小麦灌浆期土壤水分和温度及抗氧化能力的影响,探讨花后干物质积累量和粒重形成的关系。结果表明,随生育期推进,花后旗叶相对含水量(RWC)逐渐降低,丙二醛(MDA)含量逐渐升高,且PM较SM降、升幅度明显。与CK相比,覆盖显著提高花后旗叶抗氧化酶活性,增加渗透调节物质含量;开花时间越长,SM抗氧化酶活性升高的幅度越大,而PM主要提高花后7 d旗叶抗氧化能力。SM和PM的粒重分别较CK增加14.3%和19.1%(P<0.05)。相关分析表明,土壤水分(SW)是影响旗叶生理活性的关键因子,提高SW,有利于增加RWC(r=0.84^**),从而提高旗叶抗氧化能力,其中RWC和抗坏血酸酶(ASA)活性呈极显著正相关关系(r=0.82^**);ASA活性和脯氨酸(Pro)含量呈极显著正相关关系(r=0.94^**),和MDA含量呈极显著负相...     

陈玉米饲粮中添加茶多酚、维生素E和二丁基羟基甲苯对肉鸭生长性能和抗氧化功能的影响

本试验旨在研究陈玉米饲粮中添加茶多酚(TP)、维生素E和二丁基羟基甲苯(BHT)对肉鸭生长性能和抗氧化功能的影响。选取1日龄雄性北京鸭192只,随机分为4组,每组6个重复,每个重复8只。以储存3年玉米作为能量原料,Ⅰ组(对照组)饲喂基础饲粮(不添加饲料抗氧化剂),Ⅱ、Ⅲ、Ⅳ组分别饲喂在基础饲粮中添加120 mg/kg TP、维生素E和BHT的试验饲粮。试验期42 d。结果表明:1)与对照组相比,TP能显著提高22~42日龄肉鸭平均日增重(P0.05),维生素E能显著提高1~21日龄和22~42日龄肉鸭平均日增重(P0.05),BHT对肉鸭生长性能无显著影响(P0.05)。2)与对照组相比,TP能显著提高21和42日龄血清总抗氧化能力(T-AOC)以及42日龄血清过氧化氢酶(CAT)活性(P0.05),维生素E能显著提高42日龄血清CAT活性(P0.05);BHT能显著提高21日龄血清T-AOC以及21和42日龄血清CAT活性(P0.05)。由此可见,陈玉米饲粮中添加TP和维生素E对肉鸭生长性能以及抗氧化功能均有不同程度的改善,而BHT只改善了肉鸭的抗氧化功能。陈玉米饲粮中添加TP效果最好。     

马尾藻多糖对鸡脾脏淋巴细胞GSH和GSSG水平的影响

为观察马尾藻多糖(SP)对鸡脾脏淋巴细胞内氧化还原状态的影响,无菌分离鸡脾脏淋巴细胞,采用终浓度为12.5、25、50、100、200μg/mL的马尾藻多糖分别刺激培养鸡脾脏淋巴细胞4、8、12、24h,测定细胞内还原型谷胱甘肽(GSH)和氧化型谷胱甘肽(GSSG)水平。结果表明,各浓度SP与鸡脾脏淋巴细胞共同培养4、8、12h均能不同程度地升高细胞内GSH水平,降低鸡脾脏淋巴细胞内GSSG水平,升高鸡脾脏淋巴细胞内GSH/GSSG比值,与空白对照组相比差异显著或极显著(P0.05或P0.01)。说明SP可以通过调节鸡脾脏淋巴细胞内GSH和GSSG的水平来调节细胞内的氧化还原状态,从而发挥其抗氧化作用。     

抗褐化剂对荻外植体褐化和愈伤组织生长的影响

以荻(Miscanthus sacchariflorus)幼穗和诱导出的愈伤组织为材料探讨抗褐化剂聚乙烯吡咯烷酮(PVP)、抗坏血酸(Vc)、柠檬酸(CA)对外植体和愈伤组织抗褐化作用,以及愈伤诱导率及愈伤生长速度的影响。结果表明,3种抗褐化剂都能抑制外植体和愈伤组织褐化,并提高愈伤组织诱导率。添加0.2g/L PVP时荻外植体的褐变程度最低,0.2g/L CA时愈伤组织诱导率最高,为91.1%,向愈伤组织继代培养基中添加0.2g/L的Vc愈伤组织重量增加倍数最高,为21.38倍,且愈伤组织褐化率低为25.8%。     

Effect of Mediterranean saltbush (Atriplex halimus) ensilaging with two developed enzyme cocktails on feed intake,nutrient digestibility and ruminal fermentation in sheep

The aim of this study was to assess the effects of feeding Atriplex halimus (AH) silage treated with two developed enzyme cocktails to sheep on feed intake, nutrient digestibility and ruminal fermentation. The AH silage was treated without or with 2 L of ZAD1^® or ZAD2^®/1000 kg with 5% molasses and ensiled for 30 days. Barley grain (300 g/head/day) was fed as an energy supplement once daily at 10.00 hours and AH silage with or without enzyme treatment was offered ad libitum to animals twice daily at 09.00 and 16.00 hours. Sheep were fed on four experimental forage diets comprised of AH silage and barley (D1), AH silage treated with ZAD1^® and barley (D2), AH silage treated with ZAD2^® and barley (D3) and AH silage treated with a combination of ZAD1^® and ZAD2^® (1:1) and barley (D4). Ensiling AH with enzymes reduced its contents of neutral detergent fiber and acid detergent fiber. The dry matter intake of AH of D2, D3 and D4 decreased (P < 0.001) as compared to D1. However, enzyme‐treated diets had greater total digestible nutrients intake (P < 0.001) as compared to D1. The nutrients digestibility for D2, D3 and D4 were higher than those for D1 (P < 0.001), and were higher for D3 as compared to both D2 and D4. Sheep fed on D3 had highest (P < 0.001) ruminal total volatile fatty acids concentration, ammonia nitrogen concentration and microbial protein yield. It could be concluded that AH silage treated with ZAD1^® or ZAD2^® improved digestibility and rumen fermentation in sheep.     

The effect of Curcuma longa extracted (curcumin) on the quality of cryopreserved boar semen

The aim of this study was to determine the optimal concentration of curcumin needed for cryopreservation of boar semen. Semen samples (n = 9) were collected from nine Duroc boars which having proven fertility were used for routine artificial insemination. Semen samples were collected and divided into six groups (groups A‐F) according to various concentrations of curcumin in freezing extender (i.e. 0, 0.125, 0.25, 0.50, 0.75 and 1.0 mmol/L, respectively). The semen was frozen by traditional liquid nitrogen vapor method and stored at ?196°C in the liquid nitrogen tank. After storage, frozen semen samples were thawed at 50°C for 12 s and evaluated for progressive motility, viability and acrosome integrity. The present results indicated that the addition of curcumin at 0.25 (group C) or 0.50 mmol/L curcumin (group D) yielded the higher percentage of progressive motility (33.3 and 36.1%, respectively) (P < 0.001). A significantly higher percentage of acrosome integrity was found in groups B (29.7%), C (31.1%) and D (30.2%) than in the other groups (P < 0.01). However, there was no significant difference in percentage of viability among groups. In conclusion, addition to the freezing extender of curcumin during cryopreservation at a concentration of 0.25 or 0.50 mmol/L is the optimal concentration of curcumin for improving the quality (i.e. increased progressive motility and acrosome integrity) of cryopreserved boar semen.