Table of Content

21 February 2023, Volume 48 Issue 1

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Effects of Crude crude fat Level on Growth，Body Composition，Serum enzyme activity and Antioxidant Capacity of Procypris merus

XIE Yutong1，2 ，MO Wenyan1 ，CHEN Bing1 ，CAO Junming1，2 ，LI Shiyang1 ，WANG Guoxia1*

2023, 48(1):  1-7.  DOI: 10.19978/j.cnki.xmsy.2023.01.01

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A 63?day feeding trial was conducted to investigate the effects of different crude lipid levels on growth performance，body composition and serum biochemical indices of Procypris Merus，and to explore the optimal protein requirements. A total of 525 juvenile carp with an average body weight of（4.41±0.01）g were randomly divided into 5 groups with 3 replicates per group and 35 fish per replicate. Five isonitrogenous diets were formulated with 6%、8%、 10%、12% and 14% crude lipid levels. The results showed that with dietary crude lipid level increasing，the feed conversion ratio in 10%，12% and 14% groups was significantly lower than that in 6% group（P<0.05）；Protein efficiency ratio in 10%，12% and 14% groups was significantly higher than that in 6% groups（P<0.05）；weight gain rate and specific growth rate had no significant effects（P>0.05）. The condition factor of 14% was significantly higher than that of other groups（P<0.05）；the Viscerosomatic index and Hepatosomatic index had no significant change（P> 0.05）. As dietary crude lipid level increasing，whole body crude lipid content showed an increasing trend（P<0.05）， and that of 12% and 14% was significantly higher than that of other groups；the water content of 14% was significantly lower than that of other groups（P<0.05），the contents of crude protein and ash in whole fish had no significant change （P>0.05）. With the increase of crude lipid level，serum glutamic oxalacetic transaminase was decreased（P<0.05）， 6% was significantly higher than that of other groups，albumin/globulin was firstly increased and then decreased（P< 0.05），and 12% was significantly higher than that of 14% group. There were no significant differences in the contents of amylase，protease and trypsin among different levels of fat groups（P>0.05）. There were no significant differences in total antioxidant capacity，superoxide dismutase activity and alkaline phosphatase in serum and liver among all groups （P>0.05）. There were no significant differences in blood glucose，triglyceride，cholesterol，albumin，globulin and total protein among different levels（P>0.05）. In conclusion，the appropriate dietary fat level can improve feed utilization rate，increase fish body fat content，improve liver function，without affecting digestive enzyme activity and fish body health.Combined with economic benefits，the recommended dietary crude lipid level is 10%.

Performance comparative analysis of reciprocal cross progenies between dwarf yellow chickens and three normal type yellow chickens

ZENG Xianjun ，ZHANG Xiquan ，ZOU Yanni ，CHEN Jie ，HE Shizi

2023, 48(1):  8-14.  DOI: 10.19978/j.cnki.xmsy.2023.01.02

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The study on effects of Callicarpa Nudiflora Hook Granules on Blood Physiological and Biochemical Indexes of Target Animal Dogs

JI Yikuan，ZOU Daofu，LI Meidi

2023, 48(1):  15-18.  DOI: 10.19978/j.cnki.xmsy.2023.01.03

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This study aimed to evaluate the effect of Callicarpa Nudiflora Hook. et Am. granules on the blood physiological and biochemical indexes of target animal dogs. A total of 20 Chinese pastoral dogs were divided into 4 groups，with 5 dogs in each group. Dogs in the control group were fed a basal diet，and others in experiment groups were fed basal diet supplemented 0.1 g/kg BW and 0.3 g/kg BW Callicarpa Nudiflora Hook. et Am. Granules， respectively. The experiment lasted for 10 days. The clinical signs，body weight，and blood physiology and biochemistry of dogs were evaluated. The results showed that the clinical signs of the experimental dogs were normal after oral administration of different doses of Callicarpa Nudiflora Hook. et Am. Granules，and there was no obvious effect. There was no significant difference in the main blood physiological and biochemical indexes between the test group and the blank control group（P>0.05）. The results showed that Callicarpa Nudiflora Hook. granules had no significant effect on the clinical signs，body weight，and blood physiological and biochemical indexes of the experimental dogs.

Effect of fermented soybean meal on the growth performance of California perch

GUO Weigan ，YUAN Minggui ，XIANG Rong ，SUN Kaihui ，WANG Xiaoshan ，TANG Xinggang

2023, 48(1):  19-23.  DOI: 10.19978/j.cnki.xmsy.2023.01.04

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This study aimed to investigated the effects of dietary supplementation with fermented soybean meal Tejiao 001（fermented soybean meal）on the growth performance of California perch. California perch fry with the body weight of about 14 g were taken as the research object and fed with circulating water. The experiment was divided into 6 groups. The diets were supplemented with 0%，5%，7.5%，10%，12.5%，and 15% fermented soybean meal， respectively，this study lasted for 6 weeks. The results showed that dietary supplementation with 5% fermentedsoybean meal significantly increased the weight gain rate（WGR）and specific growth rate（SGR）of California perch （P＜0.05），and feed conversion ratio （FCR） of 5% fermented soybean meal group and control group were significantly better than those of 12.5% and 15% fermented soybean meal groups（P＜0.05）. The feed conversion ratio in 7.5% fermented soybean meal group was significantly better than that in 15% fermented soybean meal group（P＜ 0.05），while there was no significant difference in fecal breakdown among all groups（P>0.05）. The results showed that the basal diet supplemented with 5% or 7.5% fermented soybean meal could improve the growth performance and feed efficiency of California perch，but with the increase of fermented soybean meal，the growth performance indexes and feed efficiency of California perch decreased.

Development of a TaqMan Real􀆼time RT􀆼PCR Assay for detection of Enzootic Nasal Tumor Virus in Goats

LI Jiaming ，ZHENG Shuodong ，LUO Shicheng ，ZHANG Haoquan ，YAN Guangzhi ，CHEN Shengnan ， LIU Mingjie ，HUANG Liangzong

2023, 48(1):  24-28.  DOI: 10.19978/j.cnki.xmsy.2023.01.05

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In order to establish a rapid detection method for Enzootic nasal tumor virus of goats（ENTV ? 2）， primers and TaqMan probes were designed according to the conserved region of ENTV?2 env gene. By optimizing the reaction conditions，the ENTV ?2 TaqMan fluorescence quantitative RT ?PCR detection method was established，and its specificity，sensitivity，repeatability and clinical detection effect were verified. The results showed that the standard curve established by this method had a correlation coefficient（R2 ）of 0.998 when the concentration of recombinant plasmid was 1.019×109 —1.019×102 copies/μL，and the Ct value had a good linear relationship with the concentration of recombinant plasmid. This approach was specific for ENTV ? 2，and there was no cross ? reaction observed against other five kinds of pathogens related to goats. The minimum detection limit was 10.19 copies/μL，andthe coefficient of variation intra ?assays and inter ?assays was within 0.46% and 1.5%. It was more sensitive than the conventional RT?PCR and gave higher ENTV?2 positive detection rate（60%，12/20）than the conventional RT?PCR （30% ，6/20）from clinical samples，the total coincidence rate of the two methods was 70%（14/20）.These data indicated that the TaqMan ? based realtime RT ? PCR assay established here was an effective method with high sensitivity，specificity and reproducibility for faster and more accurate detection and quantification of ENTV?2.

Inhibition of Reuterin on Clostridium perfringens in vitro

LI Jinyan ，MA Xinyan ，XIANG Rong ，LIAO Shenquan ，LV Xiaohui ，YANG Qiao ， ZHANG Xiaoling ，YANG Xi

2023, 48(1):  29-34.  DOI: 10.19978/j.cnki.xmsy.2023.01.06

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Clostridium perfringens（Cp）is the leading pathogen of necrotizing enteritis——an acute zoonotic disease. Reuterin is a product of few probiotics in glycerol substrate，which exhibited broad spectrum antibacterial activity. The objective of this study was to observe the growth inhibition feature of Reuterin in vitro on different types of C. perfringens and to explore the stability of Reuterin under different storage temperatures. Lactobacillus reuteri was induced to synthesize Reuterin from glycerol，its concentration was determined by Acrolein ?Tryptophan method. The minimum inhibitory concentration（MIC）of C. perfringens types A，B，C，D and E were determined by 96?well plate OD600 measurement and plate titration. The antibacterial properties of Reuterin against C.perfringens was compared after 24 hours storage at - 20 ℃ ，room temperature（25 ℃）and 37 ℃ . The results exhibited that the Reuterin production concentration was 26.13 μmol/mL. Type A and D C. perfringens were the most sensitive to the Reuterin， with MIC values of 0.78 μmol/mL and 0.52 μmol/mL，respectively. Type B，C and E strains were also sensitive，MIC values were 1.57 μmol/mL，1.57 μmol/mL and 1.83 μmol/mL. In the plate titration method，all five serotype bacteria were inhibited under 0.26 μmol/mL Reuterin treatment. The bacteriostatic effect of Reuterin were measured after different storage temperatures. For C.perfringens type A and C，the growth inhibition capacity did not change，and the MICs were 0.78 μmol/mL and 1.57 μmol/mL. This study proved that Reuterin has the grow inhibitory ability on C. perfringens in vitro as one of the probiotic metabolits，and its antibacterial ability is not affected by storage temperature.

Diagnosis and treatment of porcine proliferative enteritis

XU Minsheng ，KE Haiyi ，YANG Dongxia ，SONG Shuai ，GOU Hongchao ，ZHANG Kunli ， JIANG Zhiyong ，LI Yan ，CHU Pinpin ，ZHAI Shaolun ，JIAN Yunhua ，LI Chunling

2023, 48(1):  35-38.  DOI: 10.19978/j.cnki.xmsy.2023.01.07

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Diarrhea and bloody stool occurred on a pig farm in Guangdong Province. Necropsy reveled the swelling and bleeding in the intestinal tissues. The feces of dead pigs has the black coal tar appearance. The feces were collected for laboratory test. With the pathogenesis symptoms and PCR results，porcine proliferative enteritis caused by intracellular Lawsonella was diagnosed. Tiamulin combined with other adjuvant therapy was given，which solve the case in this herd.

Comparative study on the detection of African Swine Fever virus between the commercial kit for viral DNA extraction

YANG Yunlong，FENG Yongzhi，GAO Qi，WU Xiaoyi，GONG Lang，ZHANG Guihong

2023, 48(1):  39-43.  DOI: 10.19978/j.cnki.xmsy.2023.01.08

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In order to establish a rapid and accurate detection method for African swine fever（ASF），a standarddetection of ASFV，it was found that the primers and probes provided by CADC were more sensitive to the detection of ASFV，and the DNA extraction kit of Axygen brand was more cost?effective for the detection of ASFV. plasmid and a standard curve were constructed for the late translation protein p72 gene of ASFV. The sensitivity of primers and probes provided by OIE and CADC was compared by fluorescence quantitative PCR technology，and the detection efficiency of ASFV DNA extracted by various DNA extraction kits was evaluated，providing data reference for the efficient detection of ASFV. The results showed that p72 standard plasmid had better detection efficiency and sensitivity among the standard plasmid and standard curve of p72 gene of ASFV constructed. Through the use of primers， probes and various DNA extraction kits provided by OIE and CADC for fluorescence quantitative PCR

Research progress on common factors and their interaction associated with reproductive performance and gut microbes of livestock and poultry

DONG Menglin ，CHEN Peng ，YAN Xia ，DONG Shangzhi ，LUO Xuehui ，GUO Zhaowen ，LUO Chenglong*

2023, 48(1):  44-50.  DOI: 10.19978/j.cnki.xmsy.2023.01.09

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Many factors can affect the composition of gut microbes and reproductive performance of livestock andthe compositions of gut microbes were different between genders and reproductive stages. This paper mainly elaborates on these two points from the perspective of differences in the hormone，intestinal microorganism，and reproductive performance：the differences in gut microbes richness and diversity of livestock and poultry under different reproductive performances；the differences in reproductive performance caused by intestinal microbial changes. It also provides a reference for further study on the interactive mechanism between intestinal microbial and reproductive performance. poultry. At the same time，there is an interaction between the composition of gut microbes and reproductive performance. Gut microbes can affect reproductive performance and sex hormone levels of livestock and poultry，while

Research progress on GEM􀆼PA surface display system

LU Ruiqing，JIAO Cuicui，ZHANG Mengyao，WANG Hualei，ZHANG Haili*

2023, 48(1):  51-56.  DOI: 10.19978/j.cnki.xmsy.2023.01.10

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The GEM?PA surface display system is composed of gram?positive enhancer matrix（GEM）and protein anchor（PA）. It uses GEM particles as its display core，and heterologous proteins are expressed by fusion with PA to achieve their display on the surface of GEM particles. GEM particles have many advantages such as high biosafety， ability to bind heterologous proteins，and autologous adjuvant effect. The GEM ?PA surface display system has been developed rapidly in recent years and becomes one of the new research hotspots of surface display system. At present， this system has been used in several fields including immobilizing enzymes，protein and virus purification，and development of novel vaccines. In this paper，the composition and applications of this system will be reviewed.

Recombination analysis of PRRSV epidemic strains and vaccine strains over the years in Guangdong

KANG Pu ，CHEN Qiang 2 ，LIN Mu ，WANG Xiaohu ，WANG Gang ，LU ZongJi ，CHEN Jing

2023, 48(1):  57-62.  DOI: 10.19978/j.cnki.xmsy.2023.01.11

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The complete genome sequences of 42 PRRSV strains derived from Guangdong and completerecombination events occurred in the parental strain of JXA1?R?CN?2009 from 2010 to 2018. Vaccine strains Ingelvac ATP?US?2006 and CH?1R?CN?2008 appeared as secondary parental strains in event 10，the recombinant strain of this event was Guangdong strain isolated from 2018. Recombination between vaccine strains can be seen in events 18，25， but the software also shows that this event may have evolved naturally rather than recombined. This paper has certain significance for the scientific and standardized use of modified live vaccines in Guangdong pig farms. sequences of 6 PRRSV vaccine strains were selected from all 424 PRRSV complete sequences available on GenBank database to carry out recombination analysis using RDP4(Recombination detecting program 4，RDP4) software. Recombination events between Guangdong strains were found to be concentrated in 2010，2011 and 2015. 12

Molecular epidemiological investigation of transmissible viral proventriculitis in poultry farms located in western Guangdong

PAN Xiaoting, LI Xiu, QI Nanshan, LIAO Shenquan, LI Juan, LV Minna, LIN Xuhui, CAI Haiming, HU Junjing, ZHONG Yaoguang, ZHUO Fuqiu, ZHANG Jianfei, SUN Mingfei, LI Guoqing

2023, 48(1):  63-70.  DOI: 10.19978/j.cnki.xmsy.2023.01.12

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In order to investigate the prevalence and main causes of transmissible viral proventriculitis（TVP）in chickens in western Guangdong，we collected a total of 910 glandular gastric samples（every 10 mixed into 1 pool sample，a total of 91 pool samples）from some chicken farms in western Guangdong province，and detected 8 kinds of TVP ? related viruses using real ?time PCR method. The results indicated that 42 out of the 91 samples were positive， with a positive rate of 46.2%，and a total of 6 kinds of TVP ? related viruses were detected，and double or multiple infection were found. There is no breed specificity for infected chickens in this area，but infection rate among different age groups varies significantly. It suggests that TVP infection is widespread in chicken farms in western Guangdong province，and our data will provide basic information for the epidemic characteristics as well as prevention and control of TVP in Western Guangdong.