Nitrogen partitioning and microbial protein synthesis in lactating dairy cows with different phenotypic residual feed intake

Background: Residual feed intake(RFI) is an inheritable measure of feed efficiency that is independent on level of production. However, physiological and metabolic mechanisms underlying divergent RFI are not fully elucidated.This study was conducted to investigate dietary nitrogen(N) partitioning and microbial protein synthesis in lactating dairy cows divergent in phenotypic RFI.Results: Thirty Holstein dairy cows(milk yield = 35.3 ± 4.71 kg/d;milk protein yield = 1.18 ± 0.13 kg/d;mean ± standard deviation) were selected for the experiment to derive RFI. After the RFI measurement period of 50 d, the 10 lowest RFI cows and 8 highest RFI cows were selected. The low RFI cows had lower dry matter intake(DMI, P < 0.05) than the high RFI cows, but they produced similar energy-corrected milk. The ratios of milk to DMI(1.41 vs. 1.24, P < 0.01) and energy-corrected milk to DMI(1.48 vs. 1.36, P < 0.01) were greater in low RFI cows than those in the high RFI cows. The low RFI cows had lower milk urea nitrogen than that in the high RFI cows(P = 0.05). Apparent digestibility of nutrients did not differ between two groups(P > 0.10). Compared with high RFI animals, the low RFI cows had a lower retention of N(5.72 vs. 51.4 g/d, P < 0.05) and a higher partition of feed N to milk N(29.7% vs. 26.5%, P < 0.05).Conclusions: The results suggest that differences in N partition, synthesis of microbial protein, and utilization of metabolizable protein could be part of the mechanisms associated with variance in the RFI.

Correlation between the Insertion/Deletion Mutations of Prion Protein Gene and BSE Susceptibility and Milk Performance in Dairy Cows

Objective To investigate the 23 bp and 12 bp insertion/deletion(indel)mutations within the bovine prion protein(PRNP)gene in Chinese dairy cows,and to detect the associations of two indel mutations with BSE susceptibility and milk performance.Methods Based on bovine PRNP gene sequence,two pairs of primers for testing the 23 bp and 12 bp indel mutations were designed.The PCR amplification and agarose electrophoresis were carried out to distinguish the different genotypes within the mutations.Moreover,based on previous data from other cattle breeds and present genotypic and allelic frequencies of two indels mutations in this study,the corrections between the two indel mutations and BSE susceptibility were tested,as well as the relationships between the mutations and milk performance traits were analyzed in this study based on the statistical analyses.Results In the analyzed Chinese Holstein population,the frequencies of two"del"alleles in 23 bp and 12 bp indel muations were more frequent.The frequency of haplotype of 23del-12del was higher than those of 23del-12ins and 23ins-12del.From the estimated r2and D’values,two indel polymorphisms were linked strongly in the Holstein population(D’=57.5%,r2=0.257).Compared with the BSE-affected cattle populations from the reported data,the significant differences of genotypic and allelic frequencies were found among present Holstein and some BSE-affected populations(P<0.05 or P<0.01).Similarly,there were significant frequency distribution differences of genotypes and alleles among Chinese Holstein and several previous reported healthy dairy cattle(P<0.05 or P<0.01).Moreover,association of genotype and combined genotypes of two indel polymorphisms with milk performance and resistant mastitis traits were analyzed in Holstein population,but no significant differences were found(P>0.05).Conclusions These observations revealed that the influence of two indel mutations within the bovine PRNP gene on BSE depended on the breed and they did not affect the milk production traits,which layed the foundation for future selection of resistant animals,and for improving health conditions for dairy breeding against BSE in China.

Preparation of Polyclonal Antisera of Dairy Cow S100A12 Protein

[Objective] This study aimed to prepare dairy cow anti-S100A12 antisem and develop a highly effective and sensitive immunological detection reagent for further investigation of the functions of dairy cow S100A12. [Method] Purified S100A12 protein was respectively emulsified with Freund＇s complete adjuvant and Freund＇s incomplete adjuvant as the antigen for immunizing New Zealand white rabbits to prepare the polyclonal antisera. The titer was detected using agar double diffusion assay and indirect enzyme-linked immunoserbent assay （ELISA） and the specificity was determined with Western Blot. [ Result ] The titer of anti- S100A12 antisera was 1： 8 as determined by agar double diffusion assay and over 1：409 600 by ELISA. Western Blot result showed that the polyclonal antisera could be specifically combined with S100A12 protein. [ Conclusion] The results indicated that anti-S100A12 polyclonal antibody with high fiter and high specificity was successfully obtained, which provided a novel tool for further investigation of the functions of S100A12 gene.

Interaction between Live Yeast and Dietary Rumen Degradable Protein Level: Effects on Diet Utilization in Early-Lactating Dairy Cows

Four early lactating Holstein cows were used to study the effect of live yeast (LY, Actisaf&reg;CNCM I-4407, Lesaffre Feed Additives, Marcq en Baroeul, France) supplementation on diet digestive utilization of dairy cows receiving concentrated corn silage-based diets with two rumen-degradable protein (RDP) levels. For a 33 d period, cows were fed a total mixed ration (TMR) containing an adequate level (AL) of RDP or a low level (LL, 30% below AL) by using soybean meal or tanned soybean meal, respectively: for 21 d with no LY addition followed by 12 d during which LY was added to the diet. The pH and redox potential (Eh) were recorded and ruminal fluid samples were collected over 3 consecutive days. Feces were collected individually over 48 h and individual dry matter intake (DMI) was measured for determining apparent nutrient digestibility. The effective degradability of individual feed ingredients composing both diets was evaluated with nylon bags technique. Structure of the ruminal bacterial community was studied and diversity index was calculated. Digestibility of organic matter (OM) and crude protein (CP) were lower for LL than those for AL. With LY, digestibility of OM and CP was increased: +2.4 and +0.8 points, for AL, and +3.7 and +5.9 points for LL, respectively. Live yeast reduced dietary N ruminal degradation with both AL and LL. Ruminal pH and Eh were lower with AL compared to LL: 5.95 and –167 mV vs. 6.13 and –144 mV. Live yeast increased ruminal total volatile fatty acids (VFA) (+8.6%), C2 (+10%), and C4 (+35%) contents for LL and decreased that of C3 (?9.8%) for AL. Neither the structure of bacterial populations of the rumen nor the diversity index (Shannon) was altered by treatments. Those results suggested a specific interest in using LY in RDP deficient diets for early lactating cows.

Influence of early weaning beef cows on the performance of male progeny and the need for winter protein supplementation

One hundred and three Hereford × Angus crossbred, spring-calving cows were used to determine the influence of early weaning performance of their male progeny and the need for cowherd winter supplementation. Treatments were early weaned (EW;115-d of age) and normal weaned calves (NW;220-d of age). Both intact and castrated male progeny were randomly allotted to early and normal weaning calf management treatments. Following summer grazing and weaning protocols, cows within each weaning group were randomly assigned to receive winter supplementation treatments of LOW (1.26 kg/hd/d) or HIGH (1.81 kg/hd/d) amounts of a protein supplement containing 450 g/kg CP (DM basis). Cows whose calves were weaned early gained more BW and BCS (P P P P = 0.04) BCS but similar (P = 0.74) BW when compared with cows with normally weaned calves that received 100% of their supplement (NWHIGH). Early weaning has the potential to reduce the amount of supplement required during the winter grazing period.

Feeding Protected Lysine and Methionine Modifies Milk Protein Profile in Grazing Dairy Cows

The experiment was designed to determine the effect of protected lysine (Lys) and methionine (Met) supply on milk protein profile in grazing dairy cows specifically in the caseins (CNs) and α-lactalbumin fractions. Twelve multiparous mid lactation Holstein cows producing 24 (±4.76) kg of milk were assigned to one of two treatments (six cows per treatment) during an experimental period of 21 days. In the control (C) group, cows grazed a Pennisetum clandestinum pasture and were supplemented with a commercial concentrate according to milk production. In the Met-Lys treatment, cows received the same ration supplemented with protected Lys and Met. Milk yield and composition and milk protein profile were measured at the start and the end (21st day) of the experimental period. The Tricine-SDS-PAGE and the Gel-Quant Express Analysis (Invitrogen) software were used to determine milk protein composition. Statistical analysis was performed using the SAS’s PROC MIXED procedure through a mixed model that included the animal as a random effect and the treatments as a fixed effect adjusted by covariables. Milk production averaged 23.7 (±2.0) kg cow-1 day-1 without differences between treatments (P P -1 day-1) compared to C (24.2 kg cow-1 day-1). Milk protein content (g/kg) did not differ (C = 30.4;Met-Lys = 31.1) and lactose content tended (P P β-CN also increased (P < 0.05) after protected aminoacid supply (C = 9.58;Met-Lys = 10.35). It can be concluded that milk protein composition was improved by protected Lys-Met supply without altering other compositional parameters of milk composition. Milk nutritional quality and its potential yield for cheese-making were positively enhanced.

Bacillus subtilis Co-transfected with a Lysine-rich and a Methionine-rich Protein Gene and Its Effect on Cow Milk Production

The probiotic Bacillus subtilis （B. subtilis） was widely applied in animal production as feed additive. Lysine （Lys） and methionine （Met） were the two most important limiting amino acids in livestock animal feed. Raising Lys and Met contents in B. subtilis would provide better effects for animal production and save Lys and Met supplements. We still didn＇t know whether Lys- rich and Met-rich protein genes from plants could be transfected into B. subtilis and expressed at a high level so as to improve animal production, such as milk production as an additional diet. The Lys-rich protein gene （Cflr） and Met-rich 10 ku-δ Zein were cloned from pepper anther and maize endosperm, respectively. Then they were constructed into plasmids individually and successfully cotransfected into B. subtilis. Upon IPTG induction, mRNAs and protein expressions could be observed. Lys and Met contents in the fermentation broth were raised by 65.92% and 46.39%, respectively. After feeding 200 g and 400 g· cow^-1· d^-1, transgenic B. subtilis fermentation broth, the milk yield, milk protein and milk fat contents all significantly increased. The Lys-rich protein gene （Cflr） and Met-rich 10 ku-δ Zein were successfully transfected into B. subtilis. Contents of Lys and Met in the transgenic B. subalis obviously raised and the fermentation broth of the transgenic bacteria could effectively improve milk yield and quality.

孕期因素与婴儿牛奶蛋白过敏的关系

目的:初步探讨孕期因素与婴儿牛奶蛋白过敏的关系。方法:数据来自一项“中国儿童对牛奶蛋白过敏的遗传易感性研究”的子队列,包括2020年3月1日至12月31日在北京大学人民医院出生的婴儿,根据随访至1岁时有无牛奶蛋白过敏(cow’s milk protein allergy,CMPA),分为病例组(CMPA组)和对照组。回顾性收集婴儿及其母亲孕前和孕期的临床资料,分析孕期多因素与婴儿牛奶蛋白过敏的相关性。结果:共纳入278例婴儿,CMPA患儿52例,对照组226例;男性婴儿143例,女性婴儿135例,其中男性婴儿在CMPA组比例(69.2%)高于对照组(47.3%),差异有统计学意义(P=0.004);CMPA患儿和对照组在出生体质量、出生胎龄、低出生体重儿、早产、脐带绕颈、新生儿窒息分布上差异无统计学意义(P>0.05)。母亲孕期合并免疫性疾病、贫血者以及孕期存在抗生素暴露者在CMPA组比例均高于对照组,两组之间差异有统计学意义(P<0.05);其他妊娠期合并症,如子痫/子痫前期、慢性高血压/妊娠期高血压、糖尿病/妊娠期糖尿病、甲状腺疾病等在两组分布差异无统计学意义(P>0.05)。CMPA组与对照组孕期多项血常规指标总体分布差异无统计学意义(P>0.05)。多因素Logistic回归分析发现男性婴儿、母亲妊娠合并免疫性疾病、妊娠合并贫血以及孕期抗生素暴露是CMPA发生的独立危险因素。结论:男性婴儿、母亲妊娠合并免疫性疾病、妊娠合并贫血以及孕期抗生素暴露是CMPA发生的独立危险因素。

个体化营养干预在牛奶蛋白过敏患儿中的应用

目的探讨个体化营养干预对牛奶蛋白过敏(cow milk protein allergy,CMPA)患儿营养状况及生长发育的影响。方法选取2022年2月—2023年2月惠州市中心人民医院儿科收治的60例CMPA患儿作为研究对象。其中30例作为对照组给予游离氨基酸奶粉进行喂养,另外30例作为研究组给予个体化营养干预(包括游离氨基酸奶粉喂养、辅食回避、微量元素及维生素的合理补充)。干预6个月后,对比2组患儿生长发育指标(身高、体质量、头围)、营养指标(血红蛋白、白蛋白、转铁蛋白)、血清维生素D、钙、锌水平及干预疗效。结果干预后,研究组患儿的生长发育指标优于对照组,营养状况优于对照组,血清维生素D、钙、锌水平高于对照组(P<0.05)。研究组患儿的总有效率为100%,高于对照组的83.33%,差异有统计学意义(P<0.05)。结论对CMPA患儿给予个体化营养干预可以有效促进患儿生长发育,提升患儿营养状况,临床效果显著。

氨基酸配方替代喂养对重度牛奶蛋白过敏婴儿肠道菌群特征的影响

目的探讨氨基酸配方(AAF)替代喂养对重度牛奶蛋白过敏(CMPA)婴儿肠道菌群特征的影响。方法纳入23例确诊为重度CMPA且人工喂养的≤3月龄婴儿,采用同一品牌AAF进行喂养干预。干预前及干预3个月后,收集所有婴儿的粪便样本,通过16S rRNA高通量测序及生物信息学分析评估肠道菌群的特征变化。结果干预前后,重度CMPA婴儿肠道菌群Chao1指数、Shannon指数、observed species指数、Simpson指数差异具有统计学意义(P<0.05),Beta多样性具有差异,且组间差异大于组内差异。门水平的相对丰度分析及LEfSe分析结果均显示,AAF干预后重度CMPA婴儿肠道中厚壁菌门、拟杆菌门显著富集。属水平的相对丰度分析结果显示,AAF干预后重度CMPA婴儿肠道中拟杆菌属、粪杆菌属、双歧杆菌属的相对丰度较干预前明显升高,弓形菌属、克雷伯菌属、梭菌属的相对丰度较干预前降低,LEfSe分析结果显示拟杆菌属、粪杆菌属、弓形菌属、克雷伯菌属为在丰度上有显著差异的标志物种。在种水平上相对丰度排名前10的菌群中,产气荚膜梭菌、产酸拟杆菌、丁酸梭菌、格氏乳杆菌、罗伊氏乳杆菌的相对丰度显著升高。结论AAF替代喂养可使得重度CMPA患儿肠道菌群多样性增加,拟杆菌、厚壁菌等的丰度增加。

醒脾养儿颗粒与孟鲁司特钠联合治疗小儿牛奶蛋白过敏的效果分析

目的分析醒脾养儿颗粒与孟鲁司特钠联合治疗小儿牛奶蛋白过敏的效果。方法94例牛奶蛋白过敏患儿,使用随机数字表法分为对照组与研究组,每组47例。对照组采用孟鲁司特钠咀嚼片治疗,研究组在对照组的基础上应用醒脾养儿颗粒治疗。比较两组患儿的临床疗效以及炎症因子[白细胞介素-6(IL-6)、肿瘤坏死因子-α(TNF-α)]、免疫因子(CD8^(+)、CD4^(+))水平。结果在总有效率比较中,研究组95.74%高于对照组的80.85%(P<0.05)。治疗后,研究组IL-6、TNF-α水平分别为(7.65±2.03)、(6.28±1.50)pg/ml,较对照组的(15.20±3.05)、(13.23±2.45)pg/ml低(P<0.05)。治疗后,研^(+)^(+)究组CD4水平(48.68±5.50)%较对照组的(44.50±4.86)%高,CD8水平(25.05±2.02)%较对照组的(28.64±3.05)%低(P<0.05)。结论醒脾养儿颗粒与孟鲁司特钠联合治疗小儿牛奶蛋白过敏效果确切,可以有效抑制患儿的炎症反应,提高其免疫功能,适于临床应用。

婴儿牛奶蛋白过敏的危险因素:一项多中心前瞻性巢式病例对照研究

目的探讨婴儿牛奶蛋白过敏(cow'smilkproteinallergy,CMPA)发生的危险因素。方法该研究为多中心前瞻性巢式病例对照研究。选取北京市7家医学中心0~12月龄婴儿为研究对象。共纳入CMPA婴儿200例,未发生CMPA的婴儿(对照组)799例。采用单因素和多因素logistic回归分析探讨CMPA发生的危险因素。结果单因素logistic回归分析显示,早产儿、低出生体重儿、第一胎、第一产、春季出生、夏季出生、混合/人工喂养、父母患过敏性疾病与婴儿CMPA患病风险增加有关(P<0.05)。多因素logistic回归分析显示,第一产(OR=1.89,95%CI:1.14~3.13)、春季出生(OR=3.42,95%CI:1.70~6.58)、夏季出生(OR=2.29,95%CI:1.22~4.27)、混合/人工喂养(OR=1.57,95%CI:1.10~2.26)、父亲或母亲有过敏史(OR=2.13,95%CI:1.51~3.02)、双亲有过敏史(OR=3.15,95%CI:1.78~5.56)是婴儿CMPA发生的危险因素(P<0.05)。结论第一产出生、春季出生、夏季出生、混合/人工喂养或有过敏家族史的婴儿CMPA的患病风险增加。

水解乳清蛋白改善牛乳蛋白过敏的功效及机制

目的:研究部分水解乳清蛋白(pHWP)联合不同剂量低聚果糖(FOS)和动物双歧杆菌Bb-12(Bb-12)对小鼠牛乳蛋白过敏(CMPA)的改善效果及免疫耐受调节机制。方法:4周龄雌性BALB/c小鼠随机被分成正常对照组、致敏对照组、p HWP和pHWP+FOS+Bb-12干预组。试验期间,干预组小鼠每天用含pHWP(15 mg/mL)或pHWP(15 mg/mL)+FOS(0.4/4.0mg/mL)+Bb-12(1×10^(5)/10^(6)CFU/mL)的水溶液替代常规饮用水进行饲喂干预;试验第7,14,21,28,35天,致敏对照组和干预组小鼠采用CMP(20 mg/只)+霍乱毒素(10μg/只)灌胃致敏,正常对照组小鼠灌胃无菌生理盐水;试验第42天,对所有小鼠进行CMP(50 mg/只)灌胃激发,并于激发后1 h内完成过敏症状评分,同时检测血清抗体和组胺含量、脾细胞增殖反应及上清液Th1、Th2和Treg相关细胞因子(INF-γ、IL-4和TGF-β)水平。结果:pHWP+FOS+Bb-12干预组小鼠过敏症状评分(0~1)、血清总IgE(169.4~272.7 ng/mL)、CMP特异性IgE(sIgE)(0.038~0.414 OD)和sIgG1(0.252~0.379 OD)、组胺(19.56~27.35 ng/mL)、脾细胞增殖刺激指数(1.48~1.58)及上清液IL-4(18.48~29.60 pg/mL)均显著低于致敏对照组(P<0.05),而TGF-β(143.1~177.2 pg/mL)、INF-γ(189.5~230.2 pg/mL)和INF-γ/IL-4(6.46~12.71)均显著高于致敏对照组(P<0.05)。相较于p HWP,pHWP+FOS+Bb-12对CMPA的缓解效果更强,且以使用高剂量Bb-12(1×10^(6)CFU/mL)时最为显著,部分指标包括血清总IgE、CMP-sIgE、脾细胞上清液IL-4和INF-γ/IL-4与正常对照组均无显著差异。结论:pHWP联合FOS和Bb-12可通过提高CMP免疫耐受有效改善小鼠CMPA症状,其作用可能与阻断IgE、CMP-sIgE、sIgG1和组胺分泌,抑制脾细胞增殖及上调TGF-β和INF-γ/IL-4相关。

激活转录因子4与哺乳动物雷帕霉素靶蛋白复合物1互作调控奶牛乳蛋白合成的研究进展

随着国家“双碳”战略的实施,泌乳奶牛的饲粮氮转化效率偏低及由此造成的饲料资源浪费和氮排放增加对我国奶业发展的制约作用日益突出。实际生产中,低蛋白质饲粮基础上补饲特定氨基酸(AA)是提高奶牛饲粮氮转化效率的一项重要举措,但指导其应用的理论基础尚不清晰。已有研究表明,AA补充可通过哺乳动物雷帕霉素靶蛋白复合物1(mTORC1)通路促进乳蛋白的合成,而AA缺乏则通过激活转录因子4(ATF4)抑制mTORC1的活性,且mTORC1又可作用于ATF4影响AA的转运、代谢和乳蛋白的合成。因此,ATF4与mTORC1之间的相互作用为研究限制性AA在低蛋白质饲粮条件下调控乳蛋白合成的机制提供了重要切入点。本文就ATF4与mTORC1互作在平衡AA供应与乳蛋白合成方面的研究进展进行综述,以期为限制性AA调控乳蛋白合成的途径及奶牛低蛋白质饲粮配制提供一定参考。

牛奶蛋白过敏婴儿肠道菌群特异性变化及短链脂肪酸水平分析

目的探索牛奶蛋白过敏(cow's milk protein allergy,CMPA)患儿肠道菌群及短链脂肪酸水平的变化,明确其在CMPA中的作用。方法纳入2019年8月—2020年8月在郑州大学附属儿童医院就诊的25例CMPA婴儿作为CMPA组,同时选取25例正常婴儿作为对照组。收集两组婴儿粪便200mg,采用16SrDNA高通量检测技术和液相色谱质谱联用技术分别检测肠道微生物组成及其代谢产物的变化,并将微生物多样性与代谢产物进行联合分析。结果与对照组相比,CMPA组患儿肠道菌群结构发生变化,且α-多样性显著增加(P<0.001)。与对照组相比,CMPA组患儿肠道内厚壁菌门、梭状芽孢杆菌目、拟杆菌丰度显著降低,而梭菌科、支原体科、鞘脂单胞菌科丰度显著增加(P<0.001)。代谢组学检测发现,与对照组相比,CMPA组菌群代谢产物乙酸、丁酸和异戊酸水平显著下降,并与短链脂肪酸产生菌粪杆菌属、罗氏菌属等丰度呈正相关(P<0.05)。结论CMPA患儿肠道内菌群结构发生改变,微生物多样性增加,短链脂肪酸水平降低,可能导致肠道炎症反应增加。

东弗里生绵羊奶与牛奶和山羊奶生乳品质的比较

本文综述了东弗里生绵羊所产羊奶中固形物、蛋白质等基本物质和不饱和脂肪酸等功能性物质的含量,比较了其与牛奶、山羊奶的营养成分差异,并对东弗里生绵羊奶的前景进行了展望和建议。

徐州地区0~3岁婴幼儿牛奶蛋白过敏的临床特征及影响因素分析

目的了解徐州地区0~3岁婴幼儿牛奶蛋白过敏(CMPA)的临床特征及影响因素分析,为临床诊断和治疗提供参考。方法选取2019年10月至2022年10月徐州地区0~3岁婴幼儿为研究对象,采用问卷调查的形式收集所有对象的临床特征,评估其营养水平并开展实验室检查。根据皮肤点刺试验和牛奶回避/激发试验结果确诊CMPA患儿。评估病情严重程度并分析CMPA患儿的临床特征及影响因素。根据皮肤点刺试验和IgE检查结果将患儿分为免疫球蛋白E(IgE)介导型和非IgE介导型,比较不同类型患儿临床症状和实验室检查结果。结果共纳入4983例0~3岁婴幼儿进行研究。4983例婴幼儿中共检出CMPA患儿124例,发病率为2.49%。不同年龄婴幼儿,CMPA发病率比较,差异有统计学意义(χ^(2)=10.065,P=0.002),且1~2岁和>2岁婴幼儿的CMPA发病率均高于<1岁的婴幼儿(χ^(2)=5.258,P=0.022;χ^(2)=8.055,P=0.005)。早产儿及父母有过敏史的婴幼儿CMPA发病率显著高于非早产儿及父母无过敏史者,差异均有统计学意义(χ^(2)=6.881,P=0.009;χ^(2)=9.753,P=0.002)。124例CMPA患儿中IgE介导型26例(20.97%),非IgE介导型98例(79.03%)。IgE介导型发生呕吐/胃食管反流的发生率显著低于非IgE介导型(χ^(2)=11.668,P=50.001),而发生湿疹/风团/红斑、流涕/咳嗽/喘息、口周红肿和累及2个及以上系统的发生率显著高于非IgE介导型(χ^(2)=32.975,P<0.001;χ^(2)=10.000,P=0.002;χ^(2)=17.293,P<0.001;χ^(2)=4.908,P=0.027)。IgE介导型患儿总IgE阳性比例和牛奶蛋白sIgE阳性比例均显著高于非IgE介导型(χ^(2)=19.855,P<0.001;χ^(2)=50.077,P<0.001)。多因素Logistic回归分析结果显示,年龄<1岁(OR=4.674,95%CI:2.890~7.560)、早产(OR=3.077,95%CI:1.669~5.674)、父母有过敏史(OR=3.908,95%CI:2.236~6.830)是婴幼儿发生CMPA的危险因素(P<0.05)。结论徐州地区0~3岁婴幼儿CMPA发病率随年龄升高而降低,早产儿和父母有过敏史可导致发病率升高,且不同类型CMPA患儿的临床症状差异较大。

ILC2细胞、肠道微生态与牛奶蛋白过敏关系的研究进展

2型固有淋巴细胞(ILC2)是一种免疫细胞,可分泌辅助性T细胞2,参与呼吸道过敏、蠕虫感染等疾病的发生发展。牛奶蛋白过敏(CMPA)是一种口服耐受建立失败而引起的多器官甚至全身过敏状态。受饮食方式和环境变化的影响,肠道微生态失衡导致儿童中CMPA的发生率逐年攀升。近年来对免疫相关细胞群体的研究表明,ILC2在肠道局部免疫中起重要作用。ILC2的激活和功能表达离不开肠道菌群产生的细胞因子和代谢物,未来对过敏肠道内ILC2的代谢组学研究,或将成为治疗CMPA的靶细胞。

规模奶牛场提高奶牛乳蛋白含量的营养调控技术综述

优质生鲜乳是人体获取优质蛋白的重要来源,评价生鲜乳质量优良的关键指标是其中乳蛋白含量的高低。为满足大众对生鲜乳的需求,规模化奶牛养殖场逐渐增多,但问题也随之而来。由于奶牛养殖数量较多,若不进行科学的养殖饲喂管理,极易导致乳蛋白含量低下,质量降低,不利于奶及奶制品后期加工及售卖。因此,提高生鲜乳中乳蛋白含量至关重要。本文综合概述影响生鲜乳乳蛋白含量的因素,介绍提高乳蛋白含量的措施,以提升规模化奶牛养殖场中奶牛的乳蛋白含量,促进养殖业健康发展。

低蛋白日粮对奶牛泌乳性能和养分利用的影响研究进展

近年来,随着我国畜牧业集约化和规模化养殖模式的不断发展和养殖从业者对高蛋白饲料的过度追求,豆粕等优质蛋白质饲料的需求日益增长,国际社会的贸易摩擦也导致进口豆粕的价格居高不下。同时,“碳达峰和碳中和”理念也为畜牧行业指明了新的前进方向,即减少粪污排放,走可持续发展之路。因此,在提高动物生产性能的基础上,兼顾降低日粮成本和减少粪尿氮排放的要求使得低蛋白日粮技术逐渐兴起和发展。目前,低蛋白日粮技术在单胃动物上的应用已取得显著成效,然而,由于反刍动物独特的消化结构和复杂的微生物区系使得该技术在反刍动物领域的发展相对滞后,低蛋白日粮对奶牛泌乳性能和养分利用的影响也不尽一致。本文综述了低蛋白日粮对奶牛泌乳性能和养分利用的影响,以期为牧场制定更经济合理的配方以及畜牧业的可持续发展提供理论依据。