饲粮锌水平对鹅再生羽绒品质、血清指标及毛囊发育相关基因表达的影响

Effects of Dietary Zinc Level on Regenerative Down Quality,Serum Indices and Expression of Genes Related to Follicle Development of Geese

本试验旨在探明饲粮锌水平对鹅再生羽绒品质、血清指标及毛囊发育相关基因表达的影响。试验选取在相同条件下饲养的5月龄健康霍尔多巴吉鹅128只,采绒后随机分成4组,每组4个重复,每个重复8只,公母各占1/2。4组试验鹅分别饲喂在基础饲粮(锌水平为31.68 mg/kg)中添加0、60、120和180 mg/kg一水合硫酸锌(ZnSO4·H2 O,折合成锌的添加量分别为0、21.79、43.57和65.36 mg/kg)的饲粮。预试期7 d,正试期42 d。结果显示:1)饲粮中添加不同水平的锌均可增加再生羽绒的千朵绒重以及背部、腹部、胸部绒朵长度,但差异均未达到显著水平(P>0.05)。再生羽绒的羽枝细度随着饲粮中锌添加量的增加而降低,且锌添加量为43.57和65.36 mg/kg时显著低于锌添加量为0和21.79 mg/kg时(P<0.05)。2)当饲粮中锌添加量为65.36 mg/kg时,血清中碱性磷酸酶(AKP)活性最高,显著高于锌添加量为0和21.79 mg/kg时(P<0.05);当饲粮中锌添加量为43.57 mg/kg时,血清中甘油三酯(TG)含量达到最高,显著高于锌添加量为0、21.79和65.36 mg/kg时(P<0.05)。饲粮中添加不同水平的锌对血清中总蛋白(TP)、白蛋白(ALB)和球蛋白(GLOB)含量未产生显著影响(P>0.05)。3)饲粮中添加不同水平的锌对血清中生长激素(GH)和泌乳素(PRL)浓度产生了影响显著(P<0.05),对类胰岛素生长因子-1(IGF-1)浓度未产生显著影响(P>0.05)。饲粮中锌添加量为21.79 mg/kg时,血清中GH和IGF-1浓度均最高,血清中PRL浓度则在锌添加量为43.57 mg/kg时最高。4)血清中锌含量随着饲粮中锌添加量的增加表现为先升高后降低,在锌添加量为43.57 mg/kg时达到最高。血清中钙和铁含量则随着饲粮中锌添加量的增加分别呈现上升和下降趋势。5)毛囊中表皮生长因子(EGF)基因的mRNA相对表达量随着饲粮中锌添加量的增加先升高后降低,在锌添加量为43.57 mg/kg时最高,显著高于锌添加量为65.36 mg/kg时(P<0.05)。毛囊中IGF-1基因的mRNA相对表达量也随着饲粮中锌添加量的增加先升高后降低,但各添加量之间差异不显著(P>0.05)。由此得出,在锌水平为31.68 mg/kg的基础饲粮中添加21.79~43.57 mg/kg锌(使饲粮锌水平达到53.47~75.25 mg/kg)可提高鹅血清中AKP活性以及GH、PRL和IGF-1浓度,影响血清钙和铁含量,提高再生羽绒的千朵绒重与绒朵长度,降低羽枝细度,还可以调节毛囊发育相关基因EGF和IGF-1的表达,从而促进羽绒再生。

This experiment was conducted to study the effects of dietary zinc level on regenerative down quality,serum indices and expression of genes related to follicle development of goose.A total of 128 healthy Hortobagy geese under the same feeding condition were selected and randomly divided into 4 groups after epilation,with 4 replicates in each group and 8 geese in each replicate,half male and half female.The geese in the four groups were fed diets in which ZnSO4·H2O was added in a basal diet with the additive amount of 0,60,120 and 180 mg/kg,which equaled zinc additive amount was 0,21.79,43.57 and 65.36 mg/kg,respectively.The pre-test lasted for 7 days and the formal test period lasted for 42 days.The results showed as follows:1)dietary added different levels of zinc could increase the kilo-down weight,the down length of chest,abdomen and back of regenerative down,but the differences were not significant(P>0.05).The pinnule diameter of regenerative down was decreased with the dietary zinc additive amount increasing,and when zinc additive amounts reached to 43.57 and 65.36 mg/kg,the pinnule diameter was significantly decreased compared with when zinc additive amounts were 0 and 21.79 mg/kg(P<0.05).2)The activity of serum alkaline phosphatase(AKP)reached the highest level when zinc additive amount was 65.36 mg/kg,which was significantly higher than that when zinc additive amounts were 0 and 21.79 mg/kg(P<0.05).When zinc additive amount was 43.57 mg/kg,the content of serum triglyceride(TG)reached the highest level,which was significantly higher than that when zinc additive amounts were 0,21.79 and 65.36 mg/kg(P<0.05).Dietary added different levels of zinc had no significant effects on the contents of total protein(TP),albumin(ALB)and globulin(GLOB)in serum(P>0.05).3)Dietary added different levels of zinc had significant effects on the concentrations of serum growth hormone(GH)and prolactin(PRL)(P<0.05),but had no significant effect on the concentration of serum insulin-like growth factor-1(IGF-1)(P>0.05).Serum GH and IGF-1 concentrations were the highest when zinc additive amount reached 21.79 mg/kg,and serum PRL concentration was the highest when zinc additive amount reached 43.57 mg/kg.4)With the dietary zinc additive amount increasing,the serum zinc content increased firstly and then decreased,and the highest value was found when the zinc additive amount reached 43.57 mg/kg.Serum calcium and iron content showed an upward and downward trend respectively with the dietary zinc additive amount increasing.5)The mRNA relative expression level of epidermal growth factor(EGF)gene in follicle increased firstly and then decreased with the dietary zinc additive amount increasing,when zinc additive amount reached 43.57 mg/kg,it showed the highest value and significantly higher than that when zinc additive amount was 65.36 mg/kg(P<0.05).The mRNA relative expression level of IGF-1 gene also increased firstly and then decreased with the dietary zinc additive amount increasing,but there was no significant difference among the different additive amounts(P>0.05).In conclusion,the additive amount of 21.79 to 43.57 mg/kg zinc in the basal diet with the zinc level is 31.68 mg/kg to make the dietary zinc level reaches 53.47 to 75.25 mg/kg,can increase the activity of AKP and the concentrations of GH,PRL and IGF-1 in serum,affect serum calcium and iron content,enhance the kilo-down weight and down length of regenerative down,decrease the pinnule diameter of geese.Furthermore,it can regulate the expression of EGF and IGF-1 genes related to follicle development,which can effectively promote down regeneration.