摘要
本试验旨在研究妊娠后期饲粮蛋白质水平对母驴初乳与常乳中蛋白质、脂肪和氨基酸含量的影响,为母驴饲粮蛋白质的适量供给和驴乳的优化生产提供理论依据。采用二因素完全随机试验设计,因素一为妊娠后期饲粮蛋白质水平,因素二为产后时间。选择24头年龄[(7.15±1.69)岁]、体重[(270.11±63.24)kg]、胎次[(1.63±0.48)胎]及预产天数[(58.66±4.28)d]相近的德州三粉母驴,随机分为3组,每组8头,妊娠后期分别饲喂高(12.48%,HP组)、中(11.52%,MP组)和低(10.54%,LP组)3个蛋白质水平的饲粮,产后14 d内统一饲喂相同的泌乳饲粮,并分别在产后2、6、12、24、48 h和3、5、7和14 d采集乳样。结果表明:乳中干物质、天冬氨酸(Asp)、丙氨酸(Ala)、酪氨酸(Tyr)、精氨酸(Arg)、苯丙氨酸(Phe)、缬氨酸(Val)、异亮氨酸(Ile)、亮氨酸(Leu)、组氨酸(His)及必需氨基酸(EAA)、非必需氨基酸(NEAA)、呈味氨基酸(DAA)、支链氨基酸(BCAA)的含量在HP和MP组显著高于LP组(P<0.05);乳中丝氨酸(Ser)、甘氨酸(Gly)、苏氨酸(Thr)的含量在HP、MP和LP组中依次显著降低(P<0.05);HP组乳中蛋白质、总氨基酸(TAA)的含量与EAA/TAA、EAA/NEAA最高,显著高于MP和LP组(P<0.05),乳中脂肪含量正好相反。产后2 h的初乳中,干物质、蛋白质、脂肪以及17种单一氨基酸、EAA、NEAA、DAA、BCAA的含量最高,产后6~12 h快速降低,从产后24 h开始降低趋于平缓,蛋白质及各种氨基酸含量于产后14 d降至最低,脂肪含量在产后5 d降到稳定水平。EAA/NEAA、EAA/TAA以产后2 h、6 h、72 h和14 d较低,其他时间点较高,尤以产后24 h最高。综上可知,与低蛋白质水平饲粮相比,母驴妊娠后期饲喂中、高蛋白质水平饲粮可以提高初乳中的干物质、蛋白质和多数单一氨基酸的含量,改善乳蛋白质品质;随产后时间的延长,驴乳中的脂肪、蛋白质和多数AA含量逐渐降低,以产后2 h最高,从产后24 h开始降低的趋势逐渐平缓,产后14 d降至最低。
The purpose of this experiment was to investigate the effects of dietary protein level of female donkeys during late gestation on protein,fat and amino acid contents in colostrum and regular milk,and to provide a theoretical basis for the proper supply of dietary protein and the optimal production of donkey milk.Two-factor completely random experiment design were used in this experiment,factor 1 was dietary protein level during late gestation,and factor 2 was postpartum time.Twenty-four pregnant female donkeys with similar age[(7.15±1.69)years],body weight[(270.11±63.24)kg],parity[(1.63±0.48)parities]and pre-production days[(58.66±4.28)d]were selected and randomly divided into 3 groups with 8 donkeys per group.Donkeys in the 3 groups were fed diets with high(12.48%,HP group),medium(11.52%,MP group)and low(10.54%,LP group)protein levels during late gestation,respectively,and fed the same diet after postpartum 14 days.Milk samples were collected at 2,6,12,24,48 h and 3,5,7 and 14 d after postpartum.The results showed that the contents of dry matter,aspartic acid(Asp),alanine(Ala),tyrosine(Tyr),arginine(Arg),phenylalanine(Phe),valine(Val),isoleucine(Ile),leucine(Leu),histidine(His),essential amino acids(EAA),non-essential amino acids(NEAA),delicious amino acids(DAA)and branched chain amino acids(BCAA)in milk in the HP and MP groups were significantly higher than those in the LP group(P<0.05).The contents of serine(Ser),glycine(Gly)and threonine(Thr)in the HP,MP and LP groups decreased significantly in turn(P<0.05).The contents of protein and total amino acids(TAA),EAA/TAA and EAA/NEAA in milk in the HP group were the highest,which were significantly higher than those in the MP and LP groups(P<0.05),and the changes of milk fat content among three groups was just the opposite.In colostrum at 2 h after postpartum,the contents of dry matter,protein,fat,17 kinds of single amino acids,EAA,NEAA,DAA and BCAA were the highest,which were rapidly reduced from 6 to 12 h after postpartum and leveled off after 24 h,protein and various AA contents were reduced to the lowest at 14 d after postpartum,and fat content was reduced to a stable level at 5 d after postpartum.EAA/NEAA and EAA/TAA were lower at 2,6,72 h and 14 d after postpartum,and higher at other time points,especially the highest at 24 h after postpartum.In conclusion,compared with the low protein level diet,feeing medium and high protein level diets in later gestation period of female donkeys can increase the contents of dry matter,protein and most single amino acid in colostrum of donkeys,and improve the quality of milk protein.With the prolongation of postpartum time,the contents of fat,protein and most amino acids in donkey milk gradually decrease,reach the highest level at 2 h after postpartum,then level off after 24 h after postpartum,and reach the lowest level at 14 d.
作者
梁晓帅
沈亚军
齐敬宇
郝颖
李胤豪
赵艳丽
郭晓宇
史彬林
闫素梅
LIANG Xiaoshuai;SHEN Yajun;QI Jingyu;HAO Ying;LI Yinghao;ZHAO Yanli;GUO Xiaoyu;SHI Binlin;YAN Sumei(Inner Mongolia Key Laboratory of Animal Nutrition and Feed Science,College of Animal Sciences,Inner Mongolia Agricultural University,Hohhot 010018,China;Inner Mongolia Grassland Yulu Science and Technology Animal Husbandry Co.,Ltd.,Horinger 011500,China)
出处
《动物营养学报》
CAS
CSCD
北大核心
2021年第5期2815-2826,共12页
CHINESE JOURNAL OF ANIMAL NUTRITION
基金
内蒙古自治区科技重大专项(zdzx2018001)。
关键词
蛋白质
妊娠后期
母驴
初乳
常乳
乳成分
protein
late gestation
female donkeys
colostrum
regular milk
milk composition
