Table of Content

23 April 2023, Volume 48 Issue 2

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Development trends and suggestion for swine nutrition and feed science in 2023

WANG Li, XIAO Hao, HU Shenglan, MA Xinyan, JIANG Zongyong

2023, 48(2):  1-4.  DOI: 10.19978/j.cnki.xmsy.2023.02.01

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In 2022，pig production capacity was stably increased，coupled with the continuous rise in feed raw material prices and emission reduction and carbon reduction in animal husbandry，that had brought enormous pressure to pig breeding entities. Pig industry faced severe pressure，however，new energy has been injected into healthy pig farming by the research and development of various technologies in the front ??end，mid??range，and back??end of pig farming. This paper proposed the direction for the development of the pig industry in 2023，such as accelerating the promotion of intelligent breeding technology，improving the precision level of feed preparation，strengthening precision feeding technology，increasing the development of non ?? grain feed raw materials，researching new anti ?? microbial products，adopting low??protein feed source emission reduction and so on，which aimed to provide direction reference for the healthy development of the pig industry.

Iodine Requirement for Yellow􀆼Feathered Chickens from 1 to 21 Days of Age

TAN Shujun, JIANG Zongyong, LI Long, JIANG Shouqun

2023, 48(2):  5-10.  DOI: 10.19978/j.cnki.xmsy.2023.02.02

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The purpose of this experiment was to investigate the effects of different dietary iodine levels on growth performance，immune organ index，blood T3，T4 content and T3/T4 ratio of yellow ? feathered broilers，in order to explore the appropriate level of iodine for yellow?feathered broilers during 1 to 21 days old. A total of 1440 1?day?old healthy and well?developed fast?growing Lingnan yellow?feathered male broilers were randomly divided into 6 groups with 6 replicates per group and 40 chickens in each replicate. The basal diet was supplemented with different doses of Ca（IO3）2，and the dietary iodine supplemental levels were 0.00，0.20，0.40，0.60，0.80 and 1.00 mg/kg， respectively. The results showed that the level of dietary iodine had no significant effect on daily gain，daily feed intake and ratio of feed to gain of chickens（P>0.05）. Using one?slope broken?line analysis，taking the average daily gain asthe evaluation index，the suitable dietary iodine level of chick was determined to be 0.80 mg/kg. Different dietary iodine levels had no significant effect on immune organ index，blood T3，T4 content and T3/T4 ratio of birds. To sum up，the appropriate iodine level of corn?soybean meal diet for 1?21?day?old yellow?feathered male broilers was 0.80 mg/ kg，that is，the optimum level of dietary iodine was 0.91 mg/kg.

Study of Energy Requirement of Sows during Pregnancy and Lactation and Its Application in Animal Husbandry

AN Xiaokai, GAO Kaiguo, WANG Wence, XIAO Hao

2023, 48(2):  11-17.  DOI: 10.19978/j.cnki.xmsy.2023.02.03

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Energy is the most important nutrient in the gestation stage of sows，providing fuel for sow maintenance growth，reproduction and lactation processes as well as physical activity. Accurate determination of the energy utilization of feed ingredients in sows at different growth stages can better meet the energy needs of pigs at different growth stages. This paper reviews the energy requirements of sows during gestation and lactation from four databases e.g. the Nutrient Requirements of Swine（NRC，2012），and effects of different energy substance additions on reproduction performance and physiological function of sows at different stages，to provide a theoretical reference for future research on the dynamic energy requirements of sows during reproduction.

Research progress of Newcastle disease virus vector vaccines

ZHANG Guoli，XU Shaozhu，KUANG Zhenjie，PAN Chengzhi，XIAO Jie，QI Dongmei*

2023, 48(2):  18-23.  DOI: 10.19978/j.cnki.xmsy.2023.02.04

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Newcastle Disease Virus（NDV）has been successfully used as a vaccine carrier in a variety of human and animal diseases to develop vaccines. Studies have shown that recombinant Newcastle disease virus (rNDV) vector vaccines have better performance in humoral immunity，mucosal immunity，and challenge protection compared with traditional vaccines. NDV vector has become a ideal tool for the development of safe，efficient，low toxicity，and better immunogenicity vector vaccines. The advances of novel vaccines for poultry，mammals，and humans using NDV as a vaccine vector are reviewed，to provide new ideas for the development of more epidemic vaccines using NDV vector.

Advance in Pharmacokinetics/Pharmacodynamics Models of Veterinary Antimicrobial Drugs

WEI Haitao, FANG Qiuhua, YANG Weicong, ZHANG Bingshun, LIU Shuojia

2023, 48(2):  24-29.  DOI: 10.19978/j.cnki.xmsy.2023.02.05

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The remarkable progress of veterinary antimicrobial drugs （AMDs） pharmacokinetics/ pharmacodynamics（PK/PD）models has been made in recent years. Understanding the basic concept of PK/PD model and optimizing the dosage regimen can improve the antibacterial effect of AMDs and reduce the occurrence of drug resistance. This paper introduces the research methods and progress of PK/PD model，as well as the challenges and application prospects of PK/PD model in veterinary AMDs and its future development trend，and provide a theoretical basis for the research of PK/PD model for veterinary AMDs.

Progress in the Diagnosis and Treatment of Arterial Thromboembolism Secondary to Feline Hypertrophic Cardiomyopathy

ZHOU Shuilian1，2，QU Yanyan1，BAI Yuman2，HUANG Jianjia3，XIE Wenting3，YU Yibo2，GONG Xiaopei2，QIU Wenyue2，PANG Xiaoyue2，ZHANG Xinting2，ZHANG Xin1*，SU Rongsheng2

2023, 48(2):  30-35.  DOI: 10.19978/j.cnki.xmsy.2023.02.06

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Hypertrophic cardiomyopathy（HCM）is the most common heart disease in cats. HCM in cats is characterized by centripetal thickening of ventricular walls and papillary muscle hypertrophy. The incidence of HCM followed by thromboembolism（ATE）in cats is increasing year by year. The overall survival rate of HCM was as low as 35%. This article reviewed the diagnosis and treatment of HCM and ATE in cats focusing on the main therapeutic drugs and their efficacy. It is suggested to file the predisposed breeds as soon as possible，conduct regular physical examination and screening，provide timely treatment，perform breed selection，improve the techniques of surgical treatment and integrated traditional Chinese and western medicine，use drugs prudently for treating thrombosis，try to use new antithrombolytic drugs，and so on.

Analysis of Serum Steroid Hormone Metabolism in Broiler Breeders in Different Laying Weeks

LIU Jiaxin, XIN Wentao, JIANG Xiaolong, YANG Baohe, YUAN Mingfeng, TIAN Yunbo

2023, 48(2):  36-40.  DOI: 10.19978/j.cnki.xmsy.2023.02.07

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The purpose of this experiment was aimed to compare the follicular development and serum steroid metabolism in broiler breeders of different laying weeks. Six broiler breeders were randomly selected at the beginning of preinitiation（24 weeks of age），at the peak of laying（28 weeks of age），and at the late stage of laying（47 weeks of age）. Liquid chromatogram?tandem mass spectrometry（LC?MS/MS）was used to detect serum steroid hormone levels in broiler breeders at different laying weeks of age. The results showed that the number of small yellow follicles was significantly higher at the late stage than those detected at thepeak stage（P<0.01）. The progesterone concentration in the perinatal period was highest，and significantly higher than that in the peak of egg production（P<0.01）. The levelsof 11?deoxycortisol and testosterone were the highest at the peak of egg laying.Meanwhile，the content in the opening perinatal period was the second，and the content in the late laying period was the lowest. Progesterone and estradiol levels were the lowest in the peak laying period but increased in the late laying period. In the late laying period，the content of estradiol was significantly higher than that in the peak laying period（P<0.01），and the level of progesterone was significantly higher than that in the peak laying period（P<0.05）；The level of estradiol in late laying period was significantly higher than that in the opening period（P<0.05）. The content of 17 ? hydroxypregnenolone increased gradually with the increase of laying week age，but there was no significant difference between different weeks of age. Overall，our results indicated that the low reproductive performance of broiler breeders may be related to the retardation of the development of small yellow follicles recruited into the preovulatory hierarchy and the significant increase of estradiol and progesterone in serum.

Effects of deoxynivalenol on chickens infected with Mycoplasma gallitatis and avain pathogenic Escherichia coli

LIU Jiaxu, HAN Qian, GUO Sitao, QI Zhenxiong, WANG Yongqiang, （.

2023, 48(2):  41-45.  DOI: 10.19978/j.cnki.xmsy.2023.02.08

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Mycoplasma gallitatis（MG）which often co?infect with Avian pathogenic Escherichia coli.（APEC）is an important pathogen for avian air saccultitis and put poultry industry in serious risks. In the meantime，mycotoxins as secondary metabolites produced by fungi or molds bring serious challenges to poultry health. In order to understand the correlation between mycotoxin and MG infection，7?day?old chickens were inoculated with MG S6 strain at 1×1010 CCU/mL for 3 days. Chickens were inoculated with avain pathogenic Escherichia coli（APEC）O78 strain at 1×107 CFU/mL 6 days later to induce the symptoms of diseases. During the experiment，8 mg/kg deoxynivalenol（DON）was fed through daily diet. The results showed that，at the condition of DON exposure，chickens did not show clinical symptoms of respiratory disease by MG and APEC infection，but the exposure of DON could significantly reduce the antibody level of MG and increase the detection rate of the MG in chicken blood. This study evaluated theimmunosuppressive ability of DON and confirmed that other pathogenic factors may be needed for the occurrence of multi etiological air saccultitis in chicks.

Comparative Study on Four Hydrodynamic Determination Methods of Systems in Pork

LI Hao1，3，ZHENG Enqin3，WANG Sutian1，2，XIN Haiyun1，2，YAO Zekai1，3，LI Baohong1，2，WANG Ying4， HU Bin1，2，CHENG Leiyan1，2，LI Jianhao1，2，MENG Fanming1，2*

2023, 48(2):  46-51.  DOI: 10.19978/j.cnki.xmsy.2023.02.09

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This study aimed to using 4 methods to determine the hydraulic power of pork，and combined with the actual operation to improve and evaluate the hydraulic power of pork，and then provide a theoretical basis for the identification of pork hydraulic power and meat quality. Using the 4 methods mentioned in the Ministry of Agriculture standard NY/T 1333-2007 to determine the hydraulic power，the pressure method，centrifugation method，drip loss， and cooking loss were used for parallel determination of more than 100 fresh pork samples. Moisture content（direct drying）was used as the fifth index to evaluate the water ??holding power. The water ??holding power measured by different methods of each sample was calculated by formula，and the differences of different methods were compared and analyzed. Compared with other methods，the drip loss method had the smallest error，and the average loss rate was 1.984%；the average value of the pressure method was 68.377%，and the calculation formula of the centrifugal method and the pressure method were the same，and the average value was 65.098%. However，the coefficient of variation of the centrifugation method is the largest among several methods，reaching 10.633%，the average value of the cooking method was 66.888%，and the average value of the moisture content was 68.022%，which is similar to the average value of the pressure method. The results show that drip loss was the least affected by human factors，but it was suitable for the determination of meat quality difference；the moisture content in meat can replace pressure method and centrifugation method in production，but it takes a long time；in the market Preliminary identification of meat quality could be carried out by using the cooking method，which was quicker and convenient for consumers to taste and feel the meat quality more intuitively.

Effects of Eight Plant Extracts on Antioxidant Capacity of MODE⁃K Cells

LIANG Mei，SUN Xinyi，GUO Mengru，WU Huining，ZHANG Jin，ZHAO Linlu，LIU Xiaoxi*

2023, 48(2):  52-58.  DOI: 10.19978/j.cnki.xmsy.2023.02.10

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The aim of this study was to evaluate the antioxidant capacity of eight plant extracts based on the oxidative stress model of MODE?K cells induced by lipopolysaccharide（LPS）. CCK8 method was used to detect cell viability and screen modeling conditions. The levels of IL?6，reactive oxygen species（ROS），lactate dehydrogenase （LDH），superoxide dismutase（SOD），malondialdehyde（MDA）and reduced coenzyme I（NADH）were detected by ELISA. The expression of HO?1 mRNA was detected by QPCR. The results showed that compared with the control group，the cell viability（P<0.01）was significantly reduced after 1 h of LPS treatment with 40 μg/mL. The expression of IL?6，ROS，LDH and MDA（P<0.05）was significantly increased，the expression of HO?1 mRNA（P<0.01）was significantly increased，and SOD（P<0.01）and NADH activity（P<0.05）were significantly reduced. Compared with the model group，the expression of MDA（P<0.05）and the expression of NADH and HO?1 mRNA were significantly increased（P<0.05）in the perilla seed and knotweed extract groups，while the remaining six extracts did not show significant differences. In summary，among the eight plant extracts，perilla seed and knotweed extract（20 μg/mL） improved the antioxidant effect of MODE?K cells, and the effect of perilla seed was better than that of knotweed.

Protective Effect of Chitosan ⁃ Gentamycin Conjugate on DSS ⁃ induced Ulcerative Colitis in Mice

WANG Xinchen1，2，HU Canyin1，2，YONG Yanhong1，2，LI Chengpeng3，JU Xianghong1，2*

2023, 48(2):  59-64.  DOI: 10.19978/j.cnki.xmsy.2023.02.11

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To observe the protective effect of Chitosan ? Gentamicin conjugate（CS ? GT）on Dextran Sulfate Sodium（DSS）? induced colitis in mice. Thirty healthy SPF male C57BL / 6J mice were randomly divided into 5 groups：Control group，DSS group and low，medium and high dose CS?GT group. Taking daily clinical observation and recording of mice activity，diet，body weight and fecal occult blood. All animal were euthanized and blood，colon tissues were collected on the 14th day. The changes of intestinal mucosal，the concentration of serum biochemical indexes and inflammatory factors were determined by optical microscope，biochemical analyzer，and ELISA，respectively. The results showed that compared to the control group，the body weight，and colon length were decreased in DSS?treated mice（P<0.01）. Meanwhile，we observed serious bloody stool and intestinal villus dropped in this animal. The concentration of serum ALB and TP significantly decreased（P<0.01），as well as the decrease of anti? inflammatory factors IL?4 and IL?13. But the concentration of pro?inflammatory factor IL?6 was significantly increased （P<0.01）. Compared with DSS group，the body weight and colon length of mice in medium and high dose CS?GT groups were significantly increased（P<0.05），the bleeding was improved，and the level of serum ALB and TP increased significantly（P<0.05）. The expression level of pro?inflammatory factor IL?6 decreased significantly（P< 0.05），and the anti?inflammatory factors IL?4 and IL?13 trend to increase trendy. Our results suggested that CS?GT has a significant protective effect on DSS?induced colitis in mice and is valuable to development as a functional feed additive for animal intestinal protection.

Epidemiological Investigation of Lawsonia Intracellularis in Large scale Pig Farm under the Scenarios of Antibiotic⁃Free Feed Policy

ZHI Kangfa1#，LI Fukun1，2，ZHONG Menglong1，WANG Hongcai1，LI Bo1，OU Lanxin1，HUNAG Fuqiang1， YU Xingang1，QI Dongmei2，ZHANG Haoji1*

2023, 48(2):  65-69.  DOI: 10.19978/j.cnki.xmsy.2023.02.12

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In order to provide evidence for precise prevention and control of Porcine proliferative enteropathy， the prevalence of Lawson Intracellularis in large?scale pig farms under the background of antibiotic?free feed and restricting the use of antibiotics in pig breeding industry was investigated. In this study，nested PCR and indirectELISA were used to detect fecal and serum samples from different pig farms. Under the background of antibiotic?free feed，nested PCR detection was conducted on 695 fecal samples collected from different pig farms. the overall infection rate was 23.88%. The infection rates of nursery pigs，finishing pigs and boars were 16.56%，29.58% and 24.63%，respectively. The results of the follow?up survey of the pig herds with antibiotic?free feed and under the background of restricting the use of antibiotics in pig breeding industry were as follows：the infection rate of nursery pigs at 30，44，58 and 72 days of age was 16.67%，20.00%，50.00% and 70.00%，respectively. The infection rate of gilts ranged from 44.44% to 66.67%. As for the ELISA test results，the positive rate of lawsonia intracellularis was 42.6% in 338 serum samples and the positive rate of Lawsonia Intracellularis range from 10% to 75.90% in pig farms from different provinces. The aboved results showed that the prevalence of Lawsonia Intracellulare in large?scale pig farms in China were at a high level at present. The highest infection rates of nursery pigs and gilts were 70% and 66.67% respectively. The infection rate of nursery pigs increased significantly with the increase of age. Therefore，it is necessary to pay more attention to the prevention and control of porcine proliferative enteropathy in large?scale pig farms under the background of antibiotic?free feed.

Consistency Analysis of Three ELISA Methods to Fluorescent Antibody Virus Neutralization for Detection of Rabies Antibodies

HONG Weibin，MO Zuanlan，YIN Sanhong，YE Yifei，LI Min，XU ZhenNa，HUANG ShiPin

2023, 48(2):  70-73.  DOI: 10.19978/j.cnki.xmsy.2023.02.13

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In order to select suitable kits for the detection of rabies antibodies，the FAVN method was used as the reference and compared with three ELISA kits for consistency analysis. The results showed that kit A had the best consistency and coincidence rate（86%）with Fluorescent Antibody Virus Neutralization（FAVN），its kappa value was 0.605；the Kappa value of kit B was 0.485，which was moderate consistent，the coincidence rate was 80%；the Kappa value of kit C was 0.310，indicating poor consistency between the results of the two reagents. The sensitivity and specificity of the three kits were calculated. Kit A had the highest sensitivity（92.1%）and Kit B had the highest specificity（72.7%）. This study provides a scientific basis for screening kits in clinical practice.

Comparison of Detection Sensitivity for Mycoplasma Hyorhinis Between Liquid Culture and qPCR

XUE Shaohua1，2，LÜ Zixin1，2，ZHANG Xinjie1，2，DAI Ailing1，2，YANG Xiaoyan1，2，YU Guohua1，2*

2023, 48(2):  74-80.  DOI: 10.19978/j.cnki.xmsy.2023.02.14

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To Compare the detection sensitivity between liquid culture and real ??time qPCR for the samples collected at different growth phases of Mycoplasma hyorhinis（included in the Chinese Pharmacopoeia but very time?? consuming）（not included in the Chinese Pharmacopoeia but rapid），samples were collected at three different growth phases of Mycoplasma hyorhinis ：log phase（48 h），stationary phase（96 h）and dead phase（144 h）. Then the samples were diluted 10 times serially，and the detection sensitivity was tested by liquid culture and qPCR. The results showed that the detection sensitivity of liquid culture was about 100 times higher than that of the qPCR method in the log phase and stationary phase with a high proportion of viable mycoplasma. In the dead phase when theproportion of dead mycoplasma increased significantly，the detection sensitivity of qPCR was about 1000 times higher than that of liquid culture. When the log phase sample was concentrated（about 100 times）by centrifugation，they were detected again by qPCR. Compared with the sample before concentration，the detection sensitivity of the sample was increased by 100 times. In conclusion，the main factors affecting the relative detection sensitivity of liquid culture and qPCR are the sample addition volumes in their respective systems and the proportion of viable and dead mycoplasma cells in the samples. The difference in sensitivity between the two methods caused by the former factor can be reduced by high??speed centrifugal concentration，so that the sensitivity of the two methods is the same.

Diagnosis and Treatment on a Case of Feline Sublingual Mass Removed by Ultrasonic Scalpel

DAI Jinghong1，HUANG Ruiwu2，QIU Wenyue3，SU Rongsheng3*

2023, 48(2):  81-84.  DOI: 10.19978/j.cnki.xmsy.2023.02.15

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In order to better promote the application of ultrasonic scalpel in the clinical diagnosis and treatment of pets，this paper reviewed the diagnosis and treatment process of a feline sublingual tumor treated with ultrasonic scalpel，analyzed its clinical symptoms，diagnosis，treatment，postoperative care and recovery，and discussed the difference between ultrasonic scalpel sublingual tumor resection and traditional surgery. The results showed that the sublingual mass was diagnosed as collagen fiber hyperplasia by histopathology；Compared with traditional sublingual tumor resection，ultrasonic scalpel resection has the advantages of less damage，less bleeding，accurate cutting and better prognosis. It is recommended that ultrasonic scalpel should be promoted in veterinary surgery.