中国杨梅资源及利用研究评述

杨梅属植物有60多个种,我国有6个种。综合有关文献归纳了我国6种杨梅种质资源的现状及地理分布,重点介绍了杨梅种的种质资源情况。全国现有杨梅栽培品种305个,单系120个,其中18个栽培品种通过了省级审定用于商业生产。由于杨梅具有重要的食用、药用、生态和观赏价值,经济效益、生态效益和社会效益兼备,开发潜力巨大。就杨梅果品开发、药用价值、工业原料、生态林果几方面探讨了杨梅资源的开发利用现状,重点介绍了杨梅的药用价值及活性成分。针对杨梅资源开发利用中存在的问题,提出加快杨梅医药产品的研制开发,充分利用杨梅生态效益,用于环境治理和生态重建的建议。     

葡萄品种浆果成熟期多样性及归类标准评价

对郑州葡萄圃内260个鲜食和153个酿酒品种的浆果成熟期进行了鉴定评价。在郑州地区,最早熟的葡萄种质材料早莎巴珍珠6月29日生理成熟,果实发育期48d;最晚熟的种质材料大宝10月12日成熟,果实发育期144d,在其间的103d时间里不断有成熟的葡萄品种,表现了丰富的多样性。酿酒葡萄的果实成熟期相对集中,大多数酿酒葡萄品种在8月中旬成熟,7月份和9月份成熟的葡萄品种所占的比例极少。果实发育期≤60d、61～80d、81～100d、101～120d、≥121d的品种次数呈正态分布,果实发育期81～100d的品种占收集品种的53.03%;果实发育期少于60d的极早熟品种和果实发育期多于120d的极晚熟品种所占比例较少。早、中、晚熟品种按照浆果发育期进行归类较为简便。     

母牛一胎双犊技术的研究

选择9头母牛先行人工授精、7天后再移植冷冻胚胎以生产双犊。试验结果表明,母牛产双犊达44.44%(P<0.01)。提示:采用A(I人工授精)+ET(胚胎移植)是提高母牛双犊率的有效技术措施之一。     

The IMPDH inhibitors,ribavirin and mycophenolic acid,inhibit peste des petits ruminants virus infection

Peste des petits ruminants virus (PPRV) causes highly contagious diseases in domestic and particular wild small ruminants, leading to substantial economic loss. The development of effective and cheap antiviral medications shall help to circumvent this emerging burden. In this study, we found that ribavirin, a competitive inosine-5’-monophosphate dehydrogenase (IMPDH) inhibitor, significantly inhibits the replication of PPRV. As IMPDH is a key enzyme in purine nucleotide synthesis, supplementation of exogenous guanosine attenuate the anti-PPRV effect of ribavirin. Interestingly, an uncompetitive IMPDH inhibitor, mycophenolic acid (MPA), exerted more potent antiviral effect again PPRV. Similarly, this effect was largely restored upon supplementation of guanosine. Thus, we have demonstrated that the IMPDH inhibitors ribavirin and MPA combat PPRV infection through purine nucleotide depletion. Because both regimens have been widely used in the clinic for treating viral infection or organ rejection in transplantation patients for decades, respectively, repurposing these existing safe and cheap medications may provide a new avenue for combating PPRV infection.     

Identification and characterisation of microRNAs and Piwi-interacting RNAs in cockerels’ spermatozoa by Solexa sequencing

1. There has been substantial research focused on the roles of microRNAs (miRNAs) and Piwi-interacting RNAs (piRNAs) derived from mammalian spermatozoa; however, comparatively little is known about the role of spermatozoa-derived miRNAs and piRNAs within breeding cockerels’ spermatozoa.

2. A small RNA library of cockerels’ spermatozoa was constructed using Illumina high-throughput sequencing technology. Unique sequences with lengths of 18–26 nucleotides were mapped to miRBase 21.0 and unique sequences with lengths of 25–37 nucleotides were mapped to a piRNA database. A total of 1311 miRNAs and 2448 potential piRNAs were identified. Based on stem-loop qRT-PCR, 8 miRNAs were validated.

3. Potential target genes of the abundant miRNAs were predicted, and further Kyoto Encyclopedia of Genes and Genomes database (KEGG) and Gene Ontology (GO) analyses were performed, which revealed that some candidate miRNAs were involved in the spermatogenesis process, spermatozoa epigenetic programming and further embryonic development.

5. GO and KEGG analyses based on mapping genes of expressed piRNAs were performed, which revealed that spermatozoal piRNAs could play important regulatory roles in embryonic development of offspring.

6. The search for endogenous spermatozoa miRNAs and piRNAs will contribute to a preliminary database for functional and molecular mechanistic studies in embryonic development and spermatozoa epigenetic programming.     

Branched‐chain amino acid ratios in low‐protein diets regulate the free amino acid profile and the expression of hepatic fatty acid metabolism‐related genes in growing pigs

Liver metabolism is affected by nutrients. The aim of this study was to explore the effects of low‐protein diets (17% crude protein, CP) supplemented with branched‐chain amino acids (BCAAs), including leucine (Leu), isoleucine (Ile) and valine (Val), on hepatic amino acid profile and lipid metabolism in growing pigs. The ratio of Leu : Ile : Val in all groups was 1 : 0.51 : 0.63 (20% crude protein, CP), 1 : 1 : 1 (17% CP), 1 : 0.75 : 0.75 (17% CP), 1 : 0.51 : 0.63 (17% CP) and 1 : 0.25 : 0.25 (17% CP) respectively. Results revealed that compared to the positive control group (1 : 0.51 : 0.63, 20% CP), the low‐protein diets significantly augmented the concentrations of most essential amino acids and non‐essential amino acids (p < .05), with the greatest values observed in the 1 : 0.25 : 0.25 group. Moreover, relative to the control, the low‐protein diets with the Leu : Ile : Val ratio ranging from 1 : 0.75 : 0.75 to 1 : 0.25 : 0.25 markedly downregulated the mRNA abundance of acetyl‐CoA carboxylase (ACC), lipoprotein lipase (LPL) and fatty acid‐binding protein 4 (FABP‐4) (p < .05), and upregulated the mRNA expression of hormone‐sensitive lipase (HSL), peroxisome proliferator‐activated receptor‐g coactivator‐1α (PGC‐1α), uncoupling protein 3 (UCP3) and liver carnitine palmitoyltransferase 1 (L‐CPT‐1) (p < .05). Therefore, our data suggest that protein‐restricted diets supplemented with optimal BCAA ratio, that is, 1 : 0.75 : 0.75–1 : 0.25 : 0.25, induce a shift from fatty acid synthesis to fatty acid oxidation in the liver of growing pigs. These effects may be associated with increased mitochondrial biogenesis.     

Effects of concentrate‐to‐forage ratios and 2‐methylbutyrate supplementation on ruminal fermentation,bacteria abundance and urinary excretion of purine derivatives in Chinese Simmental steers

This study evaluated the effects of dietary concentrate levels and 2‐methylbutyrate (2MB ) supplementation on performance, ruminal fermentation, bacteria abundance, microbial enzyme activity and urinary excretion of purine derivatives (PD ) in steers. Eight ruminally cannulated Simmental steers (12 months of age; 389 ± 3.7 kg of body weight) were used in a replicated 4 × 4 Latin square design with a 2 × 2 factorial arrangement. Moderate‐concentrate (400 g/kg diet [MC ]) or high‐concentrate (600 g/kg diet [HC ]) diets were fed with or without 2MB (0 g/day [2MB ?] or 15.0 g/day [2MB +]). Dry matter intake and average daily gain increased, but feed conversion ratio decreased with the HC diet or 2MB supplementation. Ruminal pH decreased, but total volatile fatty acid increased with the HC diet or 2MB supplementation. Molar proportion of acetate and acetate‐to‐propionate ratio decreased with the HC diet, but increased with 2MB supplementation. Propionate molar proportion and ruminal NH ₃‐N content increased with the HC diet, but decreased with 2MB supplementation. Neutral detergent fibre degradability decreased with the HC diet, but increased with 2MB supplementation. Crude protein degradability increased with the HC diet or 2MB supplementation. Abundance of Ruminococcus albus , Ruminococcus flavefaciens , Fibrobacter succinogenes and Bufyrivibrio fibrisolvens as well as activities of carboxymethyl cellulase, cellobiase, xylanase and pectinase decreased with the HC diet, but increased with 2MB supplementation. However, abundance of Prevotella ruminicola and Ruminobacter amylophilus as well as activities of α‐amylase and protease increased with the HC diet or 2MB supplementation. Total PD excretion also increased with the HC diet or 2MB supplementation. The results suggested that growth performance, ruminal fermentation, CP degradability and total PD excretion increased with increasing dietary concentrate level from 40% to 60% or 2MB supplementation. The observed diet × 2MB interaction indicated that supplementation of 2MB was more efficacious for improving growth performance, ruminal fermentation and total PD excretion with promoted ruminal bacteria abundance and enzyme activity in the MC diet than in the HC diet.     

β‐hydroxy‐β‐methyl butyrate promotes leucine metabolism and improves muscle fibre composition in growing pigs

The aim of this study was to investigate the effects of excess leucine (Leu) vs. its metabolites α‐ketoisocaproate (KIC) and β‐hydroxy‐β‐methyl butyrate (HMB) on Leu metabolism, muscle fibre composition and muscle growth in growing pigs. Thirty‐two pigs with a similar initial weight (9.55 ± 0.19 kg) were fed 1 of 4 diets for 45 days: basal diet, basal diet + 1.25% L‐Leu, basal diet + 1.25% KIC‐Ca, basal diet + 0.62% HMB‐Ca. Results indicated that relative to the basal diet and HMB groups, Leu and KIC groups exhibited increased Leu concentrations and decreased concentrations of isoleucine, valine and EAAs in selected muscle (p < 0.05) and had lower mRNA levels of MyHC I and higher expression of MyHC IIx/IIb (p < 0.05), and there was no significant difference between the basal and HMB‐supplemented groups. Moreover, the mRNA expression levels of AMPKα and UCP3 were higher but the myostatin mRNA levels were lower in the soleus muscle of the HMB group than those from other groups (p < 0.05). These findings demonstrated that doubling dietary Leu content exerted growth‐depressing effects in growing pigs; dietary KIC supplementation induced muscular branched‐chain amino acid imbalance and promoted muscle toward a more glycolytic phenotype; while dietary HMB supplementation promoted the generation of more oxidative muscle types and increased muscle growth specially in oxidative skeletal muscle, and these effects of HMB might be associated with the AMPKα‐Sirt1‐PGC‐1α axis and mitochondrial biogenesis.