Effects of Dietary Sodium Acetate on Lactation Performance and Rumen Microbiota of Dairy Goats北大核心CSCD

This experiment was conducted to investigate the effects of dietary sodium acetate on lactation performance and rumen microbiota of dairy goats. Fifteen healthy Xinong Saanen dairy goat ewes with similar body weight of (53.54±3.07) kg, the same parity (2 parities) and in mid-lactation [(60±5) d] were randomly divided into 3 groups with 5 replicates in each group. Dairy goats in the control group were fed a basal diet, and those in the experimental groups were fed the basal diet supplemented with 30 (experimental group I) and 60 g/ (d.head) (experimental group II) sodium acetate, respectively. The pre-trial period lasted for 7 days and the experimental period lasted for 21 days. The milk yield of dairy goats was recorded during the experiment. At the end of the experiment, milk samples were collected to analyze the changes in milk composition, and rumen contents of dairy goats were collected from two groups (control group and experimental group II) with significant differences in milk fat percentage. Gas chromatography and 16S rDNA sequencing technology were used to analyze the rumen fermentation parameters and rumen microbial composition and structure of dairy goats. The results showed as follows: 1) compared with the control group, dietary sodium acetate extremely significantly increased the daily milk yield of dairy goats (P<0.01), and the daily milk yield in experimental groups I and II was increased by 0.29 and 0.22 kg, respectively (P<0.01); in experimental group II, the milk fat percentage was significantly increased by 1.30 percentage points (P<0.01), and the non-fat solid content in milk was increased by 3.10% (P>0.05). 2) Compared with the control group, the rumen butyric acid content of dairy goats in experimental group II was significantly decreased (P<0.01), and there was no significant difference in rumen pH, the other volatile fatty acid content and acetic acid to propionic acid ratio (P>0.05). 3) Compared with the control group, the Sobs index, Chao1 index and Ace index of rumen microbiota in experimental group II were significantly increased (P<0.05); the results of similarity analysis (ANOSIM) also showed that there were significant differences in the structure of rumen microbiota between the two groups (P<0.05). 16S rDNA sequencing results showed that at the phylum level, Bacteroidetes and Firmicutes were the dominant phyla in the rumen of the two groups of dairy goats; at the genus level, Prevotella_1 was the dominant genus in the rumen. Compared with the control group, the relative abundances of Ruminococcus_1, Ruminococcaceae_UCG-005, Prevotellaceae_UCG-004 and Lachnoclostridium_12 in rumen of dairy goats in experimental group II were significantly increased (P<0.05), while the relative abundances of Succiniclasticum and Methanobrevibacter in rumen was significantly decreased (P<0.05). 4) The results of correlation analysis showed that rumen microbiota was correlated with daily milk yield, milk fat percentage, milk protein percentage and non-fat solid content of dairy goats. In conclusion, dietary 60 g/ (d.head) sodium acetate can significantly increase the daily milk yield and milk fat percentage, significantly reduce rumen butyrate content, and improve the lactation performance of dairy goats by improving rumen microbial composition and structure. © 2023 Authors. All rights reserved.     

化肥减量配施有机肥和菌剂对辣椒产量、品质和养分累积的影响

以"羊角红1号"辣椒为试材,采用田间小区试验,探究肥料的减肥增效潜力,在保证产量以及品质的前提下实现科学施肥,以期为连作区的安全高效施肥提供参考依据.结果 表明:1)与农民常规施肥方式相比,减施氮、磷、钾养分55.9％、75.8％、56.8％,并未造成辣椒产量下降,其中牛粪部分替代化肥并配施菌剂(T6)处理产量最高,增幅为12.1％,该处理的病果率降低13.03个百分点;2)推荐施肥提高了肥料偏生产力,其中T6处理增幅最大;3)推荐施肥处理显著提高了辣椒的品质,包括辣椒素以及果实维生素C含量;4)农民常规施肥辣椒根、茎、叶和果实中氮磷钾均处于较高水平,但与其它处理间差异不显著;化肥减量配施有机肥与菌剂对土壤的理化性质影响不显著.综合考虑产量、病果率、肥料偏生产力、辣椒品质,在辣椒连作种植区,适宜的安全高效施肥模式是在化肥减量的基础上,采用牛粪部分替代化肥并配施微生物菌剂.     

猪场猪瘟抗体的测定与免疫程序调整

为评价和改进某猪场实施1年以上的猪瘟免疫程序,采用间接血凝试验检测哺乳母猪、哺乳仔猪、保育猪、后备猪、肥育猪、种公猪等各阶段猪群猪瘟免疫抗体。结果发现除其他阶段抗体合格率高于70%外,3周龄哺乳仔猪和8周龄保育猪抗体合格率均低于30%。为调整起见,原免疫程序中妊娠母猪分娩前6星期增加1次猪瘟免疫,取消产后3星期的猪瘟接种。同时,将原程序断奶仔猪二免从出生后8星期提前到6星期,其他阶段猪群,包括断奶后到配种前母猪,均按原程序每年3月和9月各防疫1次。1年后,同法测得各阶段猪瘟抗体合格率均超过88%,证明新免疫程序合理可行。     

木兰科植物形态学耐涝性评价体系的建立及应用研究

木兰科植物兼具观赏、药用、材用、生态和科研价值，文化内涵深远，适应范围广，几乎涵盖整个中国，可作为建设低碳生态园林城市的重要植物材料，但相对较差的抗逆性成为制约其园林应用推广的最大瓶颈。为发掘耐涝性种质资源，研究人员根据淹水胁迫过程中木兰科植物的表型变化，选定叶色变化、植株萎蔫情况、茎基部变化和成活率变化4个指标，将其定量分级，制定等级得分标准及评价方案，然后以各指标得分的总和对耐涝性进行综合评价，建立了木兰科植物耐涝性评价体系。研究已对31木兰科种类的2～3年生种播苗进行了耐涝性鉴定，初步筛选出3个耐涝性强的木兰科优异种质。     

饲料蛋白质水平对大鳞鲃氨基酸沉积率及甲状腺激素的影响

【目的】蛋白质是水生动物重要的营养来源，为鱼体提供生长发育所必需的氨基酸。当饲料达到氨基酸平衡时，鱼体对饲料中的氨基酸充分利用，能够提高鱼体的氨基酸沉积和节约蛋白质资源。试验旨在探究饲料蛋白水平（30.24%～48.12%）对大鳞鲃（Barbus capito）幼鱼（初重（11.07±2.42）g）氨基酸组成、沉积率及甲状腺激素的影响。【方法】试验设定7个处理组，每处理设置3个重复，每重复30尾鱼，各组分别投喂蛋白水平为30.24%(G1),33.22%(G2),36.23%(G3),39.33%(G4),42.15%(G5),45.33%(G6),48.12%(G7)的饲料，养殖周期为56 d。【结果】随着饲料蛋白水平的升高，鱼体的增重量、干物质含量和饲料效率均呈先上升后下降的变化趋势，在42.15%时达到最大值。血清中三碘甲状腺原氨酸（T3）、四碘甲状腺原氨酸（T4）的含量也呈先上升后下降的变化趋势，饲料蛋白质水平为45.33%时含量最高。各处理组之间鱼体氨基酸总量及必需氨基酸总量均有显著性差异（P<0.05）,G2组达到最高值。G2组全鱼的10种必需氨基酸沉积率和氨基酸总量...