Effects of Cu2+-exchanged montmorillonite on intestinal microflora, digestibility and digestive enzyme activities of Nile tilapia

A total of 360 Nile tilapia at an average initial body weight of 3.9 g were randomly allocated to four treatments, each of which had three replicates of 30 fish per tank and used to investigate the effects of Cu²⁺‐exchanged montmorillonite (Cu‐MMT) on intestinal microflora, digestibility and digestive enzyme activities. The dietary treatments were: (i) basal diet, (ii) basal diet + 1.5 g kg^?1 MMT; (iii) basal diet + 30 mg kg^?1 copper as CuSO₄ (equivalent to the copper in the Cu‐MMT treatment group), or (iv) basal diet + 1.5 g kg^?1 Cu‐MMT. The results showed that supplementation with Cu‐MMT significantly improved growth performance as compared with the control and fish fed with Cu‐MMT had higher growth performance than those fed with MMT or CuSO₄. Supplementation with Cu‐MMT reduced (P < 0.05) the total intestinal aerobic bacterial counts and affected the composition of intestinal microflora with Aeromonas, Vibrio, Pseudomonas, Flavobacterium, Acinetobacter, Alcaligence, Enterobacteriaceae decreasing as compared with the control. Addition of MMT improved (P < 0.05) the apparent digestibility of dry matter and crude protein, and the activities of intestinal amylase, lipase, and alkaline phosphatase as compared with the control. Addition of Cu‐MMT improved (P < 0.05) the apparent digestibilities of dry matter, crude protein, ether extract, and crude ash, and the activities of total protease, amylase, lipase, and alkaline phosphatase as compared with the control. While supplementation with CuSO₄ had no (P > 0.05) effect on intestinal microflora, digestibility, and digestive enzyme activities the results showed that Cu‐MMT exhibited antibacterial activity in vivo resulting in a positive effect on digestive enzyme activities, and then promoted the digestion and absorption of dietary nutrition.     

牙鲆5个养殖群体的遗传多样性分析

利用16对微卫星分子标记对牙鲆（Paralichthys olivaceus）的5个养殖群体进行遗传多样性分析。结果表明，等位基因数为2-9个，平均等位基因数为6．0625；有效等位基因数1．2596-5．5161，平均有效等位基因数3．692；各位点的杂合度观测值（Ho）0．2200-0．8000；杂合度期望值（He）0．2061-0．8187。各群体之间无偏倚杂合度期望值从小到大依次为丹东、北戴河、威海、青岛、荣成。Kruskal-Wallis检验结果（H=0．672，df=4，P=0．955）则说明，5个群体遗传多样性差异不显著。群体间基因分化系数（Gs，）为0．0991，各群体之间存在中度遗传分化。采用UPGMA法对5个群体进行聚类，可分3类：丹东和北戴河各为一类，威海、荣成、青岛为一类，其中威海与荣成群体的分化最小。结合Hardy-Weinberg平衡，拟合度检验和遗传偏离指数（动的分析结果表明，各群体的遗传平衡状况存在很大差别。遗传变异的分析结果说明5群体遗传多样性比较丰富。     

Cloning, characterization and expression of cDNA containing major histocompatibility complex class I, IIα and IIβ genes of Japanese flounder Paralichthys olivaceus

ABSTRACT:   The nucleotide sequences of Japanese flounder Paralichthys olivaceus , major histocompatibility complex (MHC) cDNA, classical MHC class Iα, non-classical MHC class Iβ, MHC class IIα and IIβ, were determined. The domain structures and antigen binding motifs of vertebrate MHC are conserved in the Japanese flounder MHC. A phylogenetic analysis supports the classification of these genes into class I and class II MHC. Classical MHC class Iα was ubiquitously expressed, whereas the non-classical MHC class Iβ was expressed mainly in lymphoid organs, gills, intestine and stomach. The MHC classes IIα and IIβ were also ubiquitously expressed.     

日本海棠不同品种促成栽培技术

对日本海棠促成栽培进行了3 a 研究.结果表明:选5 a 生以上植株,在花盆中培养1a以上,才能满足其需冷量,打破花芽休眠,提高促成栽培质量.在促成栽培过程中温度是关键因素,只有满足一定量的有效积温,才能催花成功.     

日本樱花褐斑穿孔病的发生和防治

日本樱花褐斑穿孔病主要危害樱花叶片，致使叶片大量提早脱落，严重影响树势。发病期在4～9月，7、8月发病率增加，9月病叶大量脱落。65％代森锌、75％百菌清（科能）、75％百菌清（达科宁）、50％多菌灵4种农药防治樱花褐斑穿孔病，4月底开始喷药，10d左右1次，共喷4次，防治效果分别达95．1％、91．0％、86．3％、76．1％，可以在生产中推广应用。     

Supplemental iron and phosphorus increase dietary inclusion of cottonseed and soybean meal in olive flounder (Paralichthys olivaceus)

A long‐term feeding experiment was conducted to investigate the use of cottonseed and soybean meal (CS) with iron and phosphorus supplements in diets for olive flounder (Paralichthys olivaceus). Olive flounder with an initial average size of 28.5 ± 0.35 g (mean ± SD) were divided into 15 groups (three tanks per dietary treatment) and fed 480 g kg^?1 crude protein diets in which each of five isonitrogenous diets was formulated to contain different levels of cottonseed/soybean meal (1 : 1) to replace fish meal (FM) with iron and phosphorus supplementations. The five experimental diets were as follows: diet 1 (control), 0%CS; diet 2, 20%CS; diet 3, 30%CS; diet 4, 30%CS + Fe&P; and diet 5, 40%CS + Fe&P. After 26 weeks of feeding trial, no significant differences were observed in weight gain, feed utilization and survival among all the treatments. The total gossypol accumulation in liver of fish fed diets supplemented with iron was significantly lower than that of fish fed diets without supplementation of iron. The results indicate that the addition of iron in diets could prevent the absorption of free gossypol. The findings in this study suggest that dietary supplements of iron and phosphorus could increase the inclusion of cottonseed and soybean meal for FM replacement in diets for marine fish species.     

Performance of using opposing homozygotes for paternity testing in Japanese Black cattle

Genome-wide single nucleotide polymorphism (SNP) markers in Japanese Black cattle enable genomic prediction and verifying parent–offspring relationships. We assessed the performance of opposing homozygotes (OH) for paternity testing in Japanese Black cattle, using SNP genotype information of 50 sires and 3,420 fattened animals, 1,945 of which were fathered by the 50 genotyped sires. The number of OH was counted for each sire–progeny pair in 28,764 SNPs with minor allele frequencies of ≥0.05 in this population. Across all pairs of animals, the number of OH tended to increase as the pedigree-based coefficient of relationship decreased. With a threshold of 288 (1% of SNPs) for paternity testing, most sire–progeny pairs were detected as true relationships. The frequency of Mendelian inconsistencies was 2.4%, reflecting the high accuracy of pedigree information in Japanese Black cattle population. The results indicate the utility of OH for paternity testing in Japanese Black cattle.     

丁酸梭菌对肉鸡肠道短链脂肪酸含量和菌群多样性的影响

【目的】 探究丁酸梭菌在肉鸡消化道内的定植能力以及丁酸梭菌对肉鸡肠道短链脂肪酸含量和菌群多样性的影响。【方法】 选择90只健康状况良好的1日龄爱拔益加肉鸡,随机均分为空白组和丁酸梭菌组,每组3个重复,每个重复15只鸡。空白组灌喂生理盐水,丁酸梭菌组灌服荧光标记的丁酸梭菌,3 h及16日龄进行解剖并采集回肠上皮细胞观察荧光情况。随后另外选择30只健康状况良好的1日龄雏鸡,随机分为对照组和试验组,试验组1~6 d饲喂含丁酸梭菌的饲粮,之后饲喂基础饲粮,对照组全程饲喂基础饲粮,试验期21 d。在16和21日龄时,分别采集回肠和盲肠中段内容物,测定乙酸、丙酸、异丁酸、丁酸、异戊酸、戊酸、己酸和总短链脂肪酸含量,并进行微生物种类、物种丰度比例、菌属以及蛋白功能丰度等差异分析。【结果】 3 h及16日龄丁酸梭菌组回肠上皮细胞周围均呈现出荧光现象,表明丁酸梭菌能够定植于消化道上皮细胞。短链脂肪酸含量测定结果显示,与对照组相比,在肉鸡回肠内容物中,试验组16日龄乙酸、丙酸、异丁酸、异戊酸和戊酸含量均极显著增加（P<0.01）;21日龄丙酸、异戊酸和戊酸含量均极显著增加（P<0.01）,乙酸、异丁酸和总短链脂肪酸含量均显著增加（P<0.05）;在盲肠内容物中,试验组16日龄肉鸡丁酸和戊酸含量均极显著增加（P<0.01）,异戊酸和己酸含量显著增加（P<0.05）;21日龄丁酸和异戊酸均极显著增加（P<0.01）,乙酸、异丁酸、己酸和总短链脂肪酸均显著增加（P<0.05）。门水平上微生物种类分析发现,16日龄样本中厚壁菌门为优势菌群,丰度最高;21日龄样本中微生物种类增多,其中变形菌门、厚壁菌门和拟杆菌门为优势菌群,丰度较高,16和21日龄试验组的优势菌群均高于对照组。物种丰度比例分析结果显示,与对照组相比,16日龄试验组厌氧菌属的物种丰度比例显著增加（P<0.05）,而去氟球菌属、丛毛单胞菌属、肠杆菌属等7种菌属的物种丰度比例显著降低（P<0.05）;21日龄试验组铁杆菌属、毛球菌属等6种菌属的物种丰度比例显著增加（P<0.05）,变形菌属、浮霉菌属、装甲菌门GP5的物种丰度属显著降低（P<0.05）。菌属差异分析结果显示,16日龄试验组起重要作用的微生物是布劳特氏菌属,对照组起重要作用的微生物是梭状芽孢杆菌属和未分类毛螺旋菌属;21日龄试验组起重要作用的微生物是未分类拟杆菌、毛球菌属、乳酸杆菌目、乳球菌属等,对照组起重要作用的微生物是诺兰克酸杆菌GP4、丛毛单胞菌科等。菌群蛋白功能丰度分析结果显示,16日龄试验组甲基受体趋化性蛋白、谷胱甘肽S-转移酶、氨基酸转移酶亚基A的丰度均高于对照组,21日龄试验组ECF亚家族RNA聚合酶δ-70因子、丙氨酸的丰度均高于对照组。【结论】 丁酸梭菌可以在肉鸡回肠上皮细胞中定植;丁酸梭菌可增加肠道内容物中短链脂肪酸含量、微生物种类及有益菌属,提高物种丰度及功能蛋白丰度,从而促进肠道功能发挥。     

日本落叶松人工林生长预测的全林分模型研究

以长岭岗林场日本落叶松人工林中的固定样地以及临时样地调查数据为基础，从模型间的相容性出发，建立了包含立地指数SI、林分密度SDI、林分断面积生长模型、树高曲线动态模型和林分收获模型的全林分模型系统，着重探讨了用Korf方程构造林分断面积生长模型时有关参数与SI和SDI的关系。