水产养殖

<正>农业部印发《养殖水域滩涂规划编制工作规范》2016年12月22日,农业部印发《养殖水域滩涂规划编制工作规范》和《养殖水域滩涂规划编制大纲》,要求合理布局水产养殖生产,划定禁养区、限养区和养殖区,2018年底前全面完成《养殖水域滩涂规划》编制工作。《工作规范》规定,饮用水水源地一级保护区、自然保护区核心区和缓冲区等重点生态功能区,港口、航道等安全保护区等公共设施安全区域,有毒有害物质超过规定标准的水体为禁养区,不得开展水产养殖。限制在饮用水水源二级保护区、自然保护区实验区和外围保护地带等生态功能区开展     

农业农村部:全面推进渔业高质量发展

近期,农业农村部等七部委联合发布《国家质量兴农战略规划(2018-2022年)》。《规划》明确提岀要“依法制定岀台养殖水域滩涂规划,合理划定水产养殖区、布局限养区、明确禁养区,集成推广稻渔综合种养技术模式,到2022年建成2500个水产健康养殖示范场。压减内陆和近海捕捞强度,科学划定江河湖海限捕禁捕区域,建设海洋牧场和渔港经济区,打造海外渔业综合服务基地”等。《规划》发布为推进渔业高质量发展,建设现代渔业强国指明了方向。     

永靖县水产品质量安全管理现状、问题与对策

随着永靖县水产养殖业的快速发展,养殖规模不断扩大,水产品销售市场由当地向省内外扩张,水产品质量安全问题显得尤为重要。本文通过调查永靖县水产品质量安全管理现状,分析出管理中存在的问题,即快速发展的旅游业带来渔业水域环境污染、水产苗种和水产品检疫滞后、从业者水产品质量安全意识淡薄、渔业行政监管不到位;提出了加强水产品质量安全管理的对策,即加强苗种准入和生产管理、开展标准化生态养殖示范区建设、开展标准化生态养殖示范区建设、加强渔业水质和鱼类病害检测、加强渔药和渔用饲料等投入品使用管理强化宣传,积极引导加强渔政执法,完善管理体制。     

全国水产养殖“三区”划定基本完成

正目前,全国水产养殖的养殖区、限制养殖区和禁止养殖区"三区"划定已基本完成,水产养殖功能区划得到各级地方人民政府依法确定。据悉,经过5年多的努力,各级地方人民政府陆续完成本轮《养殖水域滩涂规划》的编制起草、协调论证和颁布施行工作。根据各省级人民政府已颁布的《养殖水域滩涂规划》有关数据统计,规划至2030年,全国共划定水产养殖的养殖区约3.5亿亩、限制养殖区约6.2亿亩和禁止养殖区约7.8亿亩,已实现养殖水域滩涂规划全覆盖。     

永靖县发展休闲渔业对策探讨

论文对甘肃省永靖县休闲渔业的发展优势与现状进行了系统调查,指出了休闲渔业在永靖县传统渔业向现代渔业转型发展过程中的重要作用。分析了休闲渔业存在的问题:休闲渔业布局不合理,缺乏规划;宣传不到位,基础设施较薄弱;从业人员素质不高,创新意识不强。并在此基础上提出了发展对策:一是确立休闲渔业的主导产业地位,提高群众和从业者素质;二是必须坚持生态发展休闲渔业理念;三是建设两大休闲渔业基地;四是实施休闲渔业场所的监管和评级制度。     

从事渔业生产须循新法

为了确保执法的权威性,公平性和公正性,新的《渔业法》在总则中增加规定:渔业行政主管部门和其所属的渔政监督管理机构及其工作人员不得参与和从事渔业生产经营活动。对可能出现的以权谋私行为加以规避。 新《渔业法》规定:单位和个人使用国家规划确定用于养殖业的全民所有的水域、滩涂的,使用者应当向县级以上地方人民政府渔业行政主管部门     

渔业养殖水域沉积物指标的分析技术

随着我国经济的持续发展,我国工业化进程不断加快,也进一步促进了渔业养殖的发展,使其水平日益提高,但是养殖污染问题随之而来,从整体上看,污染情况十分严重,如果想要从源头遏制养殖水域污染问题,就必须对沉积物进行改善。本文论述了渔业养殖水域沉积物指标的分析技术,并提出相关对策,以促进我国渔业养殖水平不断提高。     

加强渔业科技服务 提升产业发展水平

正在过去的一年间酒泉市渔业局紧紧依托资源优势,科学规划布局,加强品种引进、科技服务和现代营销,努力转变渔业发展方式,为渔业增效、渔民增收搞好服务。截止2015年底,全市养殖水面32 600亩,水产品产量1 890吨,培育水产龙头企业4家,规范和扶持渔业专业合作社15家,建成休闲渔业场所182家;发展设施渔业11家,建成疏勒河特有鱼类国家级水产种质资源保护区1个,实施渔业增殖放流苗种投放1 500多万尾。     

大力发展贵州生态渔业 推进农村产业革命

贵州省处于长江、珠江两大水系上游,总体水质较优,因地形地貌等因素缺乏池塘、湖泊等传统养殖水域资源,养殖水域资源大多为山区河道型水库.基于环保要求,贵州省于2018年全面取缔了网箱养殖.网箱取缔后,一方面省内水产品供给进一步减少,愈发依赖于省外的输入;另一方面,大范围的优质水资源“闲置”.如何合理利用“闲置”的水资源,在改善水环境和提供优质水产品等方面实现产业健康快速发展成为需要研讨的问题.笔者认为,发挥贵州省水体水质总体较优的优势,积极抓住当下省委、省政府领衔推进产业专班的机遇,大力发展贵州生态渔业是推进农村产业革命的必由之路.1贵州发展生态渔业的必要性和可行性生态渔业是利用渔业生物与渔业生态系统内的生产者、消费者和分解者之间的共生互补原理,通过系统内的能量转化和物质循环,使渔业生物和特定的渔业水域环境相适应,并佐以相应的人工控制和管理措施,以实现生态平衡、提高养殖效益的1种渔业生产模式.发展贵州生态渔业符合农业农村部等10部委联合印发的《关于加快推进水产养殖业绿色发展的意见》中“生态优先、科学利用、创新机制、融合发展”原则.     

桐梓河圆满贯水库渔业的发展规划

目前圆满贯电站已正式蓄水发电,库区水域已经形成。在原有水系环境中,渔业生产有一定基础,主要是小规模散养家鱼品种为主,养殖方式主要是小山塘小水库和稻田养鱼。近年来在当地政府引导下,名、特、优、新鱼养殖发展比较迅速。现将桐梓河圆满贯水库渔业发展规划介绍如下。     

刘家峡网箱鲟鱼鱼苗主要病原菌的分离鉴定

为查明夏季甘肃省永靖县刘家峡水库西伯利亚鲟鱼鱼苗爆发性疾病病原菌,以无菌方法从甘肃省永靖县刘家峡不同鲟鱼网箱养殖场共采集了30份濒死期及死亡鲟鱼的组织样品,采用常规细菌分离、分子生物学鉴定方法对病原菌进行了分离鉴定,并进行了人工感染实验和药敏实验。结果表明:从采集到的鲟鱼组织样品中分离到57株细菌,分别为铜绿假单胞菌、异常嗜糖气单胞菌、弗氏柠檬酸杆菌、河生莱略特氏菌、枯草芽胞杆菌、嗜水气单胞菌、鲁氏耶尔森菌、迟钝爱德华氏菌和海豚链球菌9种,除枯草芽胞杆菌及迟钝爱德华氏菌外,其余7种细菌对健康鲟鱼均具有不同程度的致病性;药敏实验分离到的7种病原菌均对诺氟沙星、氧氟沙星、环丙沙星、哌拉西林、庆大霉素、氯霉素等抗生素高度敏感,对青霉素、万古霉素、克林霉素、苯唑西林等不敏感,甚至完全耐药。该研究初步查明了甘肃省永靖县刘家峡西伯利亚鲟鱼鱼苗夏季爆发性疾病的病原菌种类,为该地区鲟鱼疾病的预防和合理用药提供了理论依据。     

持续风沙流胁迫对黑果枸杞叶片生理特性的影响

以民勤和永靖种源3龄黑果枸杞（Lycium ruthenicum）盆栽实生苗为试验材料，采用风洞模拟试验，在9 m·s^-1风速下每天1 h，持续4 d进行风沙流胁迫，记录胁迫过程中叶片形态变化，测定第4 d和第11 d叶片生理指标，以期探究民勤、永靖黑果枸杞对持续风沙流胁迫的生理响应机制。结果表明：持续风沙流胁迫后黑果枸杞叶片受损，出现褐色斑块，萎蔫，第11 d膜透性增大；与对照相比，胁迫后民勤叶片过氧化氢酶（Catalase，CAT）、超氧化物歧化酶（Superoxide dismutase，SOD）活性及脯氨酸（Proline，Pro）含量增加，丙二醛（Malonaldehyde，MDA）含量在第11 d显著下降；永靖叶片CAT、过氧化物酶（Peroxidase，POD）活性，MDA含量增加，PSⅡ最大光化学效率（F_v/F_m）在第4 d显著下降。二者其余荧光参数变化不一。研究结果可为风沙地区黑果枸杞种植选育提供一定的理论依据。     

Effects of Bacillus subtilis C‐3102 on production,hatching performance,egg quality,serum antioxidant capacity and immune response of laying breeders

To investigate the supplemental effects of Bacillus subtilis C‐3102 on the production, hatching performance, egg quality, serum antioxidant capacity and immune response of laying breeders, a total of 480 Xuefeng black‐bone (25‐week‐old) hens were randomly assigned into four treatment groups: Hens fed the basal diets with 0 (CON), 3.0 × 10⁵ (BS‐1), 6.0 × 10⁵ cfu/g (BS‐2) and 9.0 × 10⁵ (BS‐3) cfu/g of B. subtilis C‐3102. As the B. subtilis C‐3102 level increased, egg weight (linear, p < 0.01; quadratic, p = 0.003), fertility (linear, p = 0.021; quadratic, p = 0.059), hatchability (linear, p = 0.038; quadratic, p = 0.119) and yolk colour (linear, p = 0.006; quadratic, p = 0.021) increased in a linear or quadratic manner. Yolk index increased quadratically (linear, p = 0.054; quadratic, p = 0.017), and eggshell thickness (linear, p = 0.036; quadratic, p = 0.128), the activity of GSH‐Px (linear, p = 0.024; quadratic, p = 0.078), the concentration of IgM (linear, p = 0.016; quadratic, p = 0.056) and the level of AIV‐Ab (linear, p = 0.034; quadratic, p = 0.103) in the serum increased linearly as dietary supplementation of B. subtilis C‐3102 increased. The results showed that dietary treatments did not affect egg production, feed conversion ratio, egg mass, hatchability of fertile eggs, eggshell‐breaking strength, egg‐shape index, yolk percentage, Haugh unit, T‐SOD, T‐AOC, MDA, IgA and IgG concentrations and the level of NDV‐Ab in the serum. In conclusion, dietary supplementation of 9.0 × 10⁵ cfu/g B. subtilis C‐3102 in laying breeders diets may be a feasible means of effectively increasing egg weight, fertility and hatchability, and improving egg quality such as eggshell thickness, yolk index and yolk colour. Besides, B. subtilis C‐3102 can enhance the activity of GSH‐Px, the concentration of IgM and the level of AIV‐Ab in the serum.     

Dose-related antinociceptive effects of intravenous buprenorphine in cats

The dose-related antinociceptive effects of intravenous (IV) buprenorphine were evaluated in cats. Thermal (TT) and mechanical threshold (MT) devices were used for nociceptive stimulation. After baseline threshold recordings, buprenorphine was administered IV (0.01, 0.02 or 0.04 mg/kg; B1, B2 and B4, respectively) in a randomised, blinded and cross-over study. Data were analysed by ANOVA (P < 0.05) using 95% confidence intervals (CI). TT increased 15, 30, 45 min and 1 (5.2 ± 2.7 °C), 2, 3 and 4 h after B1; 15, 30, 45 min and 1 (5.1 ± 3.9 °C) and 2 h after B2, and 15, 30, 45 min and 1 (5.4 ± 3.3 °C), 2, 3, 6 and 8 h after B4. MT increased 15 and 45 min after B2 (260 ± 171 mmHg), and 30 (209 ± 116 mmHg) and 45 min and 1 and 2 h after B4. At 45 min, MT values were significantly higher after B2 compared to B1 (P < 0.05). With MT, B2 and B4 produced more antinociception and longer duration of action than B1, respectively. No dose response to thermal stimulation was detected.     

Effect of storage duration on egg quality,embryo mortality and hatchability in FUNAAB-ɑ chickens

Effect of extended storage on egg quality, embryo mortality and hatchability in FUNAAB-ɑ chickens was determined. Hatchable eggs (n = 288; weighing 53.2 ± 4.67 g) collected from a flock of FUNAAB-ɑ layer breeder hens aged 32 weeks were stored in egg tray with broad end up under 16 ± 1.5°C for either 0, 4, 8, 12, 16 or 20 d. Before incubation, eight eggs from each group were evaluated for internal and external quality traits. Remaining eggs were set in an incubator and transferred into hatcher on embryonic day 18. Data collected were subjected to one-way analysis of variance. Egg weight loss (EWL; p < .001), surface area (p < .001), yolk diameter (p < .001), inner and outer blastoderm diameters (p < .05) and dead in germ (DIG; p < .001) increased with storage duration while yolk height (p < .001), yolk index (p < .001), albumen weight (p < .05), albumen height (p < .05), albumen index (p < .01), Haugh's unit (HU; p < .05), fertility (p < .001), hatchability of set (HATCHS; p < .001) and fertile eggs (p < .05) decreased. Weight losses of 0, 1.2, 2.2, 3.4, 4.6 and 6.1% were recorded in egg stored for 0, 4, 8, 12, 16 and 20 days respectively. Eggs stored beyond 8 days exhibited higher DIG and lower HATCHS. Shell percentage in 4 days storage (11.4%) was lower (p < .05) than in 16 days storage (13.4%). Shell thickness was similar in eggs stored for 0 to 12 days, but 8 days storage (0.60 mm) had thinner (p < .01) shell than day 16 (0.71 mm) and day 20 (0.73 mm) storage. Internal quality unit (IQU) was higher (p < .05) in fresh eggs (180.4) than in 12 days (167.8) and 20 days (167.8) stored eggs. Extended storage of FUNAAB-ɑ eggs caused EWL, surface area shrinkage, lowered HU and IQU, loss of yolk and albumen quality, increased blastoderm diameters and DIG, and decreased egg fertility and HATCHS from day 8 forward. Storing FUNAAB-ɑ eggs beyond 8 days reduced quality parameters; therefore, other mitigating factors are recommended when storing beyond 8 days.     

Low‐density lipoproteins and milk serum proteins improve the quality of stallion sperm after vitrification in straws

Lipids and proteins can be used for sperm vitrification to preserve the integrity of sperm membranes or to increase the viscosity of the medium. This study evaluated the effect of low‐density lipoproteins (LDL) and milk serum proteins (Pronexcell) for stallion sperm vitrification. Hippex extender (Barex Biochemical Products, The Netherlands), plus 1% of bovine serum albumin and 100 mM of trehalose, was used as control for sperm vitrification. In experiment 1, different concentrations of LDL (L1 = 0.25, L2 = 0.5, L3 = 1%) and in experiment 2 of Pronexcell (P1 = 1, P2 = 5, P3 = 10%) were added to control extender. Vitrification was performed in 0.25‐ml straws directly plunged into liquid nitrogen. Total motility (TM, %) and progressive motility (PM, %) were analysed by CASA, and plasma membrane (IMS, %) and acrosome membrane integrity (AIS, %) were assessed under epifluorescence microscopy. Post‐warmed sperm parameters were compared between treatments by ANOVA. Results were expressed as mean ± SEM. In both experiments, the minimum concentration of LDL and Pronexcell obtained significantly higher values (p < 0.01) than the control extender for TM (L1 = 52.95 ± 4.4; P1 = 58.99 ± 4.6; C = 30.88 ± 3.0), PM (L1 = 36.79 ± 5.5; P1 = 47.25 ± 4.3; C = 19.20 ± 2.4), IMS (L1 = 68.88 ± 3.6; P1 = 47.25 ± 4.3; C = 52.81 ± 2.6) and AIS (L1 = 45.88 ± 3.6; P1 = 47.25 ± 4.3; C = 26.00 ± 2.1). No differences in sperm parameters were found among different concentrations of LDL or Pronexcell. In conclusion, the addition of 0.25% LDL and 1% Pronexcell to the vitrification extender is recommended to improve the quality of stallion sperm after vitrification.     

Comparison of the sedative effects of intranasal or intramuscular dexmedetomidine at low doses in healthy dogs: a randomized clinical trial

ObjectiveTo compare the sedative effects of dexmedetomidine administered either intranasally or intramuscularly to healthy dogs.Study designProspective, randomized, blinded, clinical trial.AnimalsA group of 16 client-owned healthy dogs.MethodsDogs were randomly allocated to one of two groups that were administered dexmedetomidine 5 μg kg^–1 via either the intranasal route (IN_Dex), through a mucosal atomization device in one nostril, or the intramuscular route (IM_Dex), into the epaxial muscles. Ease of intranasal administration, sedation score, onset of sedation, cardiopulmonary variables, mechanical nociceptive thresholds (MNTs) and response to venous catheterization were recorded at 0 (baseline), 5, 10, 15, 20, 25, 30, 35, 40 and 45 minutes, following drug administration. Data were compared with the one-way anova, Mann-Whitney U test, and chi-square test, where appropriate.ResultsGroups were not different for age, sex, weight, body condition score or temperament. Sedation scores, MNTs and response to intravenous catheter placement were not different when dexmedetomidine was administered by either route (p = 0.691; p = 0.630 and p = 0.435, respectively). Onset of sedation was not different between groups IN_Dex and IM_Dex reaching a score of 4.2 ± 0.9 and 5.5 ± 1.2 at 9 ± 5 and 8 ± 4 minutes, respectively (p = 0.467). The highest sedation score was achieved at 30 and 35 minutes and sedation scores were 9.7 ± 2.0 and 9.5 ± 2.3 in groups IN_Dex and IM_Dex, respectively (p = 0.799). Respiratory rate was higher in group IN_Dex (p = 0.014), while there were no differences between routes in heart rate (p = 0.275), systolic (p = 0.957), diastolic (p = 0.837) or mean arterial pressure (p = 0.921).Conclusions and clinical relevanceIntranasal administration of dexmedetomidine at 5 μg kg^–1 provides effective sedation in healthy dogs.     

Betaine improves growth performance,liver health,antioxidant status,breast meat yield,and quality in broilers fed a mold-contaminated corn-based diet

Betaine has been demonstrated to improve growth performance and antioxidant status of animals under various stress conditions. However, there is no literature on the effects of betaine in animals exposed to mycotoxins, which are among the most prevalent contaminants in feed. Therefore, this study was conducted to evaluate the influence of dietary betaine on broilers fed a diet based on mold-contaminated corn (MCC). A total of 192 Ross 308 male broiler chicks at 1 d of age were randomly divided into 4 groups with 6 replicates and fed an MCC-based diet supplemented with 0, 250, 500, and 1,000 mg/kg betaine, respectively. Betaine increased average daily gain (linear, P = 0.030) and decreased feed conversion ratio (linear, P = 0.027) of broilers during d 1 – 21, and decreased feed conversion ratio during d 22 – 42 (linear, P = 0.012; quadratic, P < 0.001) and d 1 – 42 (linear, P = 0.003; quadratic, P = 0.004), whereas feed intake was not affected. Total cholesterol (linear, P = 0.024), alanine aminotransferase (quadratic, P < 0.001) and alkaline phosphatase (linear, P = 0.007; quadratic, P = 0.025) activities in serum were decreased by betaine. Betaine linearly increased breast muscle yield (P = 0.003) and pH_24 h (P = 0.008), and decreased drip loss (P = 0.022). Betaine increased (linear, P = 0.025; quadratic, P = 0.016) total superoxide dismutase activity in breast muscle and reduced malondialdehyde content in serum (linear, P = 0.006), liver (quadratic, P = 0.006) and breast muscle (linear, P = 0.003). Moreover, the zearalenone concentrations in breast muscle were linearly decreased by betaine (P = 0.006). It was concluded that betaine could improve growth performance, liver health, antioxidant status, and breast meat yield and quality, and reduce zearalenone residue in broilers fed the MCC-based diet, especially at 500 or 1,000 mg/kg.     

A meta-analysis on effects of supplementing low-quality roughages with foliages from browses and tree fodders on intake and growth in sheep

A meta-analysis of data obtained from previous studies was conducted to understand the responses of foliage supplementation on intakes of basal DM (BDMI) and total DM (TDMI), and daily gain (ADG). Thirty-four published studies containing 223 treatments and 1127 sheep met criteria for inclusion in the meta-analysis. Major predictive variables considered were percentages of foliages in diet (SD), CP in foliages (PS), NDF in foliages (FS), NDF in forages (FB), CP in basal roughages (PB), CP in diet (PD) and foliage CP intake (SPI). TDMI (g/d) increased quadratically (P < 0.001) with increasing PS, FS, SPI (R² = 0.66), PB, SD (R² = 0.58) and PD (R² = 0.73). The maximal response of TDMI were 778 g/d at 42% of SD, 894 g/d at 19.8% PD, 893 g/d at 148 g/d SPI and 749 g/d at 26.4% PS (P < 0.001; R² = 0.58, 0.73, 0.66, and 0.37, respectively). BDMI increased quadratically with increasing SD, PD and PB, but decreased quadratically (P < 0.001) with increasing PS (P < 0.001; R² = 0.07). The breakpoint of BDMI was 570 g/d at 6.58% of PD in the diet (P < 0.001, R² = 0.28). Overall, BDMI responded at very low level of SD in the diet, peaking at 7.6% SD with BDMI of 572 g/d (P < 0.001, R² = 0.72). However, when PB was less than 3%, the maximal BDMI was 489 g/d at foliage levels of 25.7%. When PB was between 3 and 6%, maximal BDMI was at 13% of foliage in the diet and the basal forage intake of 597 g/d; whereas, BDMI decreased linearly with SD when PB was greater than 6%. BDMI (g/d) decreased quadratically when foliage CP percentages were lesser than 10%, but increased quadratically with PS when foliage CP percentages were greater than 10%. ADG responded positively and quadratically to PS, SPI, SD, PD and TDMI (g/d) and the relationships were moderate to high. However, ADG (g/d) decreased linearly with increasing FS (P < 0.001, R² = 0.35). The maximal ADG was 42 g/d at 43% of SD, 41 g/d at 9.4% PD, 42 g/d at 53 g/d SPI, 35 g/d at 25% PS and 46 g/d at TDMI of 889 g/d (P < 0.001; R² = 0.74, 0.84, 0.74, 0.29 and 0.74, respectively). It is concluded that the interactions of quality and quantity of foliage supplements and quality of basal forages affect intakes of basal and total DM, and growth in sheep.     

Influence of dietary lysine level on whole-body protein turnover, plasma IGF-I, GH and insulin concentration in growing pigs

Four growing pigs (initial liveweight 25.9 ± 0.54 kg, final liveweight 43.0 ± 1.06 kg) were used to study the effect of dietary lysine level on nutrient digestibility, whole-body protein turnover, plasma insulin-like growth factor-I (IGF-I), growth hormone (GH), insulin, glucose, and urea nitrogen (PUN). Four diets, containing 7.0 g (L1), 9.5 g (L2), 12.0 g (L3) and 14.5 g (L4) lysine per kg diet respectively, were formulated as experimental treatments. The animals and diets were allocated in a 4 × 4 Latin square design. Nitrogen (N) metabolism and whole-body protein turnover were measured by classical method and single-dose ¹⁵N end-product method, respectively. The blood samples were taken at the end of each experimental period. Results showed that N retention (NR) and N biological value (NBV) were significantly increased from L1 to L4 (P < 0.05). However, differences in NR and NBV between L2, L3 and L4 were not significant (P > 0.05). There was no significant difference on dry matter (DM) digestibility, organic matter (OM) digestibility and N digestibility between different treatments (P > 0.05). Whole-body protein synthesis, protein degradation and protein accretion increased markedly from L1 to L2 (P < 0.05), but did not increase further from L2 to L4. Whole-body protein accretion (y, g/kg W^0.75/d) increased with dietary lysine (x, g/kg) in a quadratic manner: y = − 0.09x² + 2.12x − 5.14 (r² = 0.96, n = 4, P < 0.05).The results also showed that differences in plasma IGF-I, GH, glucose and PUN concentration between different treatments were not significant (P > 0.05). Plasma insulin concentration (y, μIU/ml) was increased with dietary lysine (x, g/kg) in a quadratic manner: y = 0.23x² − 4.10x + 32.25 (r² = 0.99, n = 4, P < 0.05), but it was not found that plasma insulin concentration was related to NR. A significant correlation was found between NR (y, g/d) and plasma IGF-I (x, ng/ml): y = − 3.1 × 10^− 3x² + 1.31x − 122.28 (r² = 0.99, n = 4, P < 0.05).It was concluded that dietary lysine level had a significant influence on NR and whole-body protein turnover but not on plasma IGF-I and GH concentration. Plasma IGF-I may be an important factor controlling N metabolism of growing pigs. Further research was needed to study the mechanism.